diff --git a/.github/workflows/plugins.yml b/.github/workflows/plugins.yml
index b0f22ec3e..cfef25a97 100644
--- a/.github/workflows/plugins.yml
+++ b/.github/workflows/plugins.yml
@@ -1,16 +1,21 @@
-name: Plugin Backwards Compatibility Tests
+---
+name: Plugin
+
+# To debug locally:
+#   npm install -g act
+#   cd /Users/broz/src/solargraph/ && act pull_request -j run_solargraph_rails_specs # e.g.
 
 on:
   push:
-    branches: [ master ]
+    branches: [master]
   pull_request:
-    branches: [ master ]
+    branches: [master]
 
 permissions:
   contents: read
 
 jobs:
-  test:
+  regression:
     runs-on: ubuntu-latest
 
     steps:
@@ -19,7 +24,7 @@ jobs:
       uses: ruby/setup-ruby@v1
       with:
         ruby-version: '3.0'
-        bundler-cache: false
+        bundler-cache: true
     - uses: awalsh128/cache-apt-pkgs-action@latest
       with:
         packages: yq
@@ -29,14 +34,154 @@ jobs:
         echo 'gem "solargraph-rails"' > .Gemfile
         echo 'gem "solargraph-rspec"' >> .Gemfile
         bundle install
+        bundle update rbs
+    - name: Configure to use plugins
+      run: |
+        bundle exec solargraph config
+        yq -yi '.plugins += ["solargraph-rails"]' .solargraph.yml
+        yq -yi '.plugins += ["solargraph-rspec"]' .solargraph.yml
+    - name: Install gem types
+      run: bundle exec rbs collection update
+    - name: Ensure typechecking still works
+      run: bundle exec solargraph typecheck --level typed
+    - name: Ensure specs still run
+      run: bundle exec rake spec
+  rails:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: '3.0'
+        bundler-cache: false
+    - uses: awalsh128/cache-apt-pkgs-action@latest
+      with:
+        packages: yq
+        version: 1.0
+    - name: Install gems
+      run: |
+        echo 'gem "solargraph-rails"' > .Gemfile
+        bundle install
+        bundle update rbs
     - name: Configure to use plugins
       run: |
         bundle exec solargraph config
         yq -yi '.plugins += ["solargraph-rails"]' .solargraph.yml
+    - name: Install gem types
+      run: bundle exec rbs collection update
+    - name: Ensure typechecking still works
+      run: bundle exec solargraph typecheck --level typed
+    - name: Ensure specs still run
+      run: bundle exec rake spec
+  rspec:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: '3.0'
+        bundler-cache: false
+    - uses: awalsh128/cache-apt-pkgs-action@latest
+      with:
+        packages: yq
+        version: 1.0
+    - name: Install gems
+      run: |
+        echo 'gem "solargraph-rspec"' >> .Gemfile
+        bundle install
+        bundle update rbs
+    - name: Configure to use plugins
+      run: |
+        bundle exec solargraph config
         yq -yi '.plugins += ["solargraph-rspec"]' .solargraph.yml
     - name: Install gem types
-      run: bundle exec rbs collection install
+      run: bundle exec rbs collection update
     - name: Ensure typechecking still works
       run: bundle exec solargraph typecheck --level typed
     - name: Ensure specs still run
       run: bundle exec rake spec
+
+  # run_solargraph_rspec_specs:
+  #   # check out solargraph-rspec as well as this project, and point the former to use the latter as a local gem
+  #   runs-on: ubuntu-latest
+  #   steps:
+  #   - uses: actions/checkout@v3
+  #   - name: clone https://github.com/lekemula/solargraph-rspec/
+  #     run: |
+  #      cd ..
+  #      git clone https://github.com/lekemula/solargraph-rspec.git
+  #      cd solargraph-rspec
+  #   - name: Set up Ruby
+  #     uses: ruby/setup-ruby@v1
+  #     with:
+  #       ruby-version: '3.0'
+  #       bundler-cache: false
+  #   - name: Install gems
+  #     run: |
+  #      cd ../solargraph-rspec
+  #      echo "gem 'solargraph', path: '../solargraph'" >> Gemfile
+  #      bundle install
+  #   - name: Run specs
+  #     run: |
+  #       cd ../solargraph-rspec
+  #       bundle exec rake spec
+
+  run_solargraph_rails_specs:
+    # check out solargraph-rails as well as this project, and point the former to use the latter as a local gem
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - name: clone solargraph-rails
+      run: |
+       cd ..
+       git clone https://github.com/iftheshoefritz/solargraph-rails.git
+       cd solargraph-rails
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        # solargraph-rails supports Ruby 3.0+
+        ruby-version: '3.0'
+        bundler-cache: false
+        bundler: latest
+      env:
+        MATRIX_SOLARGRAPH_VERSION: '>=0.56.0.pre1'
+        MATRIX_RAILS_VERSION: "7.0"
+    - name: Install gems
+      run: |
+       set -x
+       BUNDLE_PATH="${GITHUB_WORKSPACE:?}/vendor/bundle"
+       export BUNDLE_PATH
+       cd ../solargraph-rails
+       echo "gem 'solargraph', path: '${GITHUB_WORKSPACE:?}'" >> Gemfile
+       bundle install
+       bundle update rbs
+       RAILS_DIR="$(pwd)/spec/rails7"
+       export RAILS_DIR
+       cd ${RAILS_DIR}
+       bundle install
+       bundle exec --gemfile ../../Gemfile rbs --version
+       bundle exec --gemfile ../../Gemfile rbs collection install
+       cd ../../
+       # bundle exec rbs collection init
+       # bundle exec rbs collection install
+      env:
+        MATRIX_SOLARGRAPH_VERSION: '>=0.56.0.pre1'
+        MATRIX_RAILS_VERSION: "7.0"
+        MATRIX_RAILS_MAJOR_VERSION: '7'
+    - name: Run specs
+      run: |
+        BUNDLE_PATH="${GITHUB_WORKSPACE:?}/vendor/bundle"
+        export BUNDLE_PATH
+        cd ../solargraph-rails
+        bundle exec solargraph --version
+        bundle info solargraph
+        bundle info rbs
+        bundle info yard
+        bundle exec rake spec
+      env:
+        MATRIX_SOLARGRAPH_VERSION: '>=0.56.0.pre1'
+        MATRIX_RAILS_VERSION: "7.0"
diff --git a/.github/workflows/rspec.yml b/.github/workflows/rspec.yml
index 35f7a1d13..175d8684e 100644
--- a/.github/workflows/rspec.yml
+++ b/.github/workflows/rspec.yml
@@ -21,14 +21,29 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: ['3.0', '3.1', '3.2', '3.3', '3.4', 'head']
+        ruby-version:
+          - '3.0'
+          - '3.1'
+          - '3.2'
+          - '3.3'
+          - '3.4'
+          # - 'head' - see https://github.com/castwide/solargraph/issues/1022
         rbs-version: ['3.6.1', '3.9.4', '4.0.0.dev.4']
         # Ruby 3.0 doesn't work with RBS 3.9.4 or 4.0.0.dev.4
         exclude:
+          # Ruby 3.0 doesn't work with RBS 3.9.4 or 4.0.0.dev.4
           - ruby-version: '3.0'
             rbs-version: '3.9.4'
           - ruby-version: '3.0'
             rbs-version: '4.0.0.dev.4'
+          # Missing require in 'rbs collection update' - hopefully
+          # fixed in next RBS release
+          - ruby-version: 'head'
+            rbs-version: '4.0.0.dev.4'
+          - ruby-version: 'head'
+            rbs-version: '3.9.4'
+          - ruby-version: 'head'
+            rbs-version: '3.6.1'
     steps:
     - uses: actions/checkout@v3
     - name: Set up Ruby
@@ -47,7 +62,8 @@ jobs:
     - name: Install gems
       run: |
         bundle install
-        bundle update rbs # use latest available for this Ruby version
+    - name: Install types
+      run: bundle exec rbs collection update
     - name: Run tests
       run: bundle exec rake spec
   undercover:
@@ -64,7 +80,11 @@ jobs:
         ruby-version: '3.4'
         bundler-cache: false
     - name: Install gems
-      run: bundle install
+      run: |
+        bundle install
+        bundle update rbs # use latest available for this Ruby version
+    - name: Install types
+      run: bundle exec rbs collection update
     - name: Run tests
       run: bundle exec rake spec
     - name: Check PR coverage
diff --git a/.github/workflows/typecheck.yml b/.github/workflows/typecheck.yml
index 0ae8a3d8a..2a7068116 100644
--- a/.github/workflows/typecheck.yml
+++ b/.github/workflows/typecheck.yml
@@ -36,4 +36,4 @@ jobs:
     - name: Install gem types
       run: bundle exec rbs collection install
     - name: Typecheck self
-      run: SOLARGRAPH_ASSERTS=on bundle exec solargraph typecheck --level typed
+      run: SOLARGRAPH_ASSERTS=on bundle exec solargraph typecheck --level strong
diff --git a/.rubocop.yml b/.rubocop.yml
index a73324db2..6ec069a5b 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -34,6 +34,10 @@ Metrics/ParameterLists:
   Max: 7
   CountKeywordArgs: false
 
+# we don't use the spec/solargraph directory, instead keeping things
+# directly under spec.
+RSpec/SpecFilePathFormat:
+  Enabled: false
 
 # we tend to use @@ and the risk doesn't seem high
 Style/ClassVars:
diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index d8283c5c6..245cec1bb 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -1,51 +1,44 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config --no-exclude-limit --no-offense-counts --no-auto-gen-timestamp`
-# using RuboCop version 1.79.2.
+# using RuboCop version 1.80.0.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
 # This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: Include.
-# Include: **/*.gemspec
 Gemspec/AddRuntimeDependency:
   Exclude:
     - 'solargraph.gemspec'
 
 # This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: Severity, Include.
-# Include: **/*.gemspec
+# Configuration parameters: Severity.
 Gemspec/DeprecatedAttributeAssignment:
   Exclude:
     - 'solargraph.gemspec'
     - 'spec/fixtures/rdoc-lib/rdoc-lib.gemspec'
 
-# Configuration parameters: EnforcedStyle, AllowedGems, Include.
+# Configuration parameters: EnforcedStyle, AllowedGems.
 # SupportedStyles: Gemfile, gems.rb, gemspec
-# Include: **/*.gemspec, **/Gemfile, **/gems.rb
 Gemspec/DevelopmentDependencies:
   Exclude:
     - 'solargraph.gemspec'
 
 # This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: TreatCommentsAsGroupSeparators, ConsiderPunctuation, Include.
-# Include: **/*.gemspec
+# Configuration parameters: TreatCommentsAsGroupSeparators, ConsiderPunctuation.
 Gemspec/OrderedDependencies:
   Exclude:
     - 'solargraph.gemspec'
 
 # This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: Severity, Include.
-# Include: **/*.gemspec
+# Configuration parameters: Severity.
 Gemspec/RequireMFA:
   Exclude:
     - 'solargraph.gemspec'
     - 'spec/fixtures/rdoc-lib/rdoc-lib.gemspec'
     - 'spec/fixtures/rubocop-custom-version/specifications/rubocop-0.0.0.gemspec'
 
-# Configuration parameters: Severity, Include.
-# Include: **/*.gemspec
+# Configuration parameters: Severity.
 Gemspec/RequiredRubyVersion:
   Exclude:
     - 'spec/fixtures/rdoc-lib/rdoc-lib.gemspec'
@@ -71,7 +64,6 @@ Layout/BlockAlignment:
 Layout/ClosingHeredocIndentation:
   Exclude:
     - 'spec/diagnostics/rubocop_spec.rb'
-    - 'spec/rbs_map/conversions_spec.rb'
 
 # This cop supports safe autocorrection (--autocorrect).
 # Configuration parameters: AllowForAlignment.
@@ -99,7 +91,6 @@ Layout/ElseAlignment:
     - 'lib/solargraph/source/chain/call.rb'
     - 'lib/solargraph/source_map/clip.rb'
     - 'lib/solargraph/source_map/mapper.rb'
-    - 'lib/solargraph/type_checker.rb'
     - 'lib/solargraph/type_checker/rules.rb'
     - 'lib/solargraph/yard_map/mapper.rb'
 
@@ -107,7 +98,6 @@ Layout/ElseAlignment:
 # Configuration parameters: EmptyLineBetweenMethodDefs, EmptyLineBetweenClassDefs, EmptyLineBetweenModuleDefs, DefLikeMacros, AllowAdjacentOneLineDefs, NumberOfEmptyLines.
 Layout/EmptyLineBetweenDefs:
   Exclude:
-    - 'lib/solargraph/doc_map.rb'
     - 'lib/solargraph/language_server/message/initialize.rb'
     - 'lib/solargraph/pin/delegated_method.rb'
 
@@ -116,7 +106,6 @@ Layout/EmptyLines:
   Exclude:
     - 'lib/solargraph/bench.rb'
     - 'lib/solargraph/complex_type/unique_type.rb'
-    - 'lib/solargraph/doc_map.rb'
     - 'lib/solargraph/language_server/message/extended/check_gem_version.rb'
     - 'lib/solargraph/language_server/message/initialize.rb'
     - 'lib/solargraph/pin/delegated_method.rb'
@@ -126,13 +115,6 @@ Layout/EmptyLines:
     - 'spec/pin/symbol_spec.rb'
     - 'spec/type_checker/levels/strict_spec.rb'
 
-# This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: EnforcedStyle.
-# SupportedStyles: empty_lines, empty_lines_except_namespace, empty_lines_special, no_empty_lines, beginning_only, ending_only
-Layout/EmptyLinesAroundClassBody:
-  Exclude:
-    - 'lib/solargraph/rbs_map/core_map.rb'
-
 # This cop supports safe autocorrection (--autocorrect).
 # Configuration parameters: EnforcedStyle.
 # SupportedStyles: empty_lines, empty_lines_except_namespace, empty_lines_special, no_empty_lines
@@ -159,7 +141,6 @@ Layout/EndAlignment:
     - 'lib/solargraph/source/chain/call.rb'
     - 'lib/solargraph/source_map/clip.rb'
     - 'lib/solargraph/source_map/mapper.rb'
-    - 'lib/solargraph/type_checker.rb'
     - 'lib/solargraph/type_checker/rules.rb'
     - 'lib/solargraph/yard_map/mapper.rb'
 
@@ -178,7 +159,6 @@ Layout/ExtraSpacing:
   Exclude:
     - 'lib/solargraph/parser/parser_gem/node_processors/opasgn_node.rb'
     - 'lib/solargraph/pin/closure.rb'
-    - 'lib/solargraph/pin/local_variable.rb'
     - 'lib/solargraph/rbs_map/conversions.rb'
     - 'lib/solargraph/type_checker.rb'
     - 'spec/spec_helper.rb'
@@ -236,7 +216,6 @@ Layout/HashAlignment:
 Layout/HeredocIndentation:
   Exclude:
     - 'spec/diagnostics/rubocop_spec.rb'
-    - 'spec/rbs_map/conversions_spec.rb'
     - 'spec/yard_map/mapper/to_method_spec.rb'
 
 # This cop supports safe autocorrection (--autocorrect).
@@ -252,7 +231,6 @@ Layout/IndentationWidth:
     - 'lib/solargraph/parser/parser_gem/node_processors/block_node.rb'
     - 'lib/solargraph/pin/method.rb'
     - 'lib/solargraph/pin/namespace.rb'
-    - 'lib/solargraph/rbs_map.rb'
     - 'lib/solargraph/shell.rb'
     - 'lib/solargraph/source/chain/call.rb'
     - 'lib/solargraph/source_map/clip.rb'
@@ -306,7 +284,6 @@ Layout/MultilineMethodCallIndentation:
 # SupportedStyles: aligned, indented
 Layout/MultilineOperationIndentation:
   Exclude:
-    - 'lib/solargraph/api_map.rb'
     - 'lib/solargraph/language_server/host/dispatch.rb'
     - 'lib/solargraph/source.rb'
 
@@ -340,7 +317,6 @@ Layout/SpaceAroundOperators:
   Exclude:
     - 'lib/solargraph/library.rb'
     - 'lib/solargraph/parser/parser_gem/node_methods.rb'
-    - 'lib/solargraph/pin/local_variable.rb'
     - 'lib/solargraph/source.rb'
     - 'lib/solargraph/source/change.rb'
     - 'lib/solargraph/source/cursor.rb'
@@ -348,7 +324,6 @@ Layout/SpaceAroundOperators:
     - 'lib/solargraph/source_map/clip.rb'
     - 'lib/solargraph/workspace/config.rb'
     - 'spec/library_spec.rb'
-    - 'spec/yard_map/mapper_spec.rb'
 
 # This cop supports safe autocorrection (--autocorrect).
 # Configuration parameters: EnforcedStyle, EnforcedStyleForEmptyBraces.
@@ -399,7 +374,6 @@ Layout/SpaceBeforeComma:
 # SupportedStylesForEmptyBraces: space, no_space
 Layout/SpaceInsideBlockBraces:
   Exclude:
-    - 'lib/solargraph/api_map.rb'
     - 'lib/solargraph/api_map/store.rb'
     - 'lib/solargraph/diagnostics/update_errors.rb'
     - 'lib/solargraph/language_server/host.rb'
@@ -491,10 +465,6 @@ Lint/AssignmentInCondition:
   Exclude:
     - 'lib/solargraph/library.rb'
 
-Lint/BinaryOperatorWithIdenticalOperands:
-  Exclude:
-    - 'lib/solargraph/api_map/source_to_yard.rb'
-
 # This cop supports unsafe autocorrection (--autocorrect-all).
 Lint/BooleanSymbol:
   Exclude:
@@ -523,7 +493,6 @@ Lint/DuplicateMethods:
     - 'lib/solargraph/pin/base.rb'
     - 'lib/solargraph/pin/signature.rb'
     - 'lib/solargraph/rbs_map.rb'
-    - 'lib/solargraph/rbs_map/core_map.rb'
     - 'lib/solargraph/source/chain/link.rb'
 
 # Configuration parameters: AllowComments, AllowEmptyLambdas.
@@ -571,7 +540,6 @@ Lint/NonAtomicFileOperation:
 # This cop supports safe autocorrection (--autocorrect).
 Lint/ParenthesesAsGroupedExpression:
   Exclude:
-    - 'lib/solargraph.rb'
     - 'lib/solargraph/parser/parser_gem/node_chainer.rb'
     - 'spec/language_server/host_spec.rb'
     - 'spec/source_map/clip_spec.rb'
@@ -627,7 +595,7 @@ Lint/UnmodifiedReduceAccumulator:
     - 'lib/solargraph/pin/method.rb'
 
 # This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: AutoCorrect, IgnoreEmptyBlocks, AllowUnusedKeywordArguments.
+# Configuration parameters: IgnoreEmptyBlocks, AllowUnusedKeywordArguments.
 Lint/UnusedBlockArgument:
   Exclude:
     - 'lib/solargraph/language_server/message/workspace/did_change_workspace_folders.rb'
@@ -635,16 +603,14 @@ Lint/UnusedBlockArgument:
     - 'spec/language_server/transport/data_reader_spec.rb'
 
 # This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: AutoCorrect, AllowUnusedKeywordArguments, IgnoreEmptyMethods, IgnoreNotImplementedMethods, NotImplementedExceptions.
+# Configuration parameters: AllowUnusedKeywordArguments, IgnoreEmptyMethods, IgnoreNotImplementedMethods, NotImplementedExceptions.
 # NotImplementedExceptions: NotImplementedError
 Lint/UnusedMethodArgument:
   Exclude:
-    - 'lib/solargraph.rb'
     - 'lib/solargraph/complex_type/type_methods.rb'
     - 'lib/solargraph/convention/base.rb'
     - 'lib/solargraph/diagnostics/base.rb'
     - 'lib/solargraph/diagnostics/update_errors.rb'
-    - 'lib/solargraph/doc_map.rb'
     - 'lib/solargraph/pin/namespace.rb'
     - 'lib/solargraph/rbs_map/conversions.rb'
     - 'lib/solargraph/source.rb'
@@ -665,16 +631,8 @@ Lint/UnusedMethodArgument:
     - 'spec/doc_map_spec.rb'
 
 # This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: AutoCorrect, ContextCreatingMethods, MethodCreatingMethods.
-Lint/UselessAccessModifier:
-  Exclude:
-    - 'lib/solargraph/api_map.rb'
-
-# This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: AutoCorrect.
 Lint/UselessAssignment:
   Exclude:
-    - 'lib/solargraph/api_map.rb'
     - 'lib/solargraph/doc_map.rb'
     - 'lib/solargraph/language_server/message/extended/check_gem_version.rb'
     - 'lib/solargraph/language_server/message/extended/document_gems.rb'
@@ -703,7 +661,6 @@ Lint/UselessConstantScoping:
     - 'lib/solargraph/rbs_map/conversions.rb'
 
 # This cop supports unsafe autocorrection (--autocorrect-all).
-# Configuration parameters: AutoCorrect.
 Lint/UselessMethodDefinition:
   Exclude:
     - 'lib/solargraph/pin/signature.rb'
@@ -714,7 +671,6 @@ Metrics/AbcSize:
     - 'lib/solargraph/api_map.rb'
     - 'lib/solargraph/api_map/source_to_yard.rb'
     - 'lib/solargraph/complex_type.rb'
-    - 'lib/solargraph/doc_map.rb'
     - 'lib/solargraph/language_server/host.rb'
     - 'lib/solargraph/language_server/message/initialize.rb'
     - 'lib/solargraph/library.rb'
@@ -759,6 +715,7 @@ Metrics/ClassLength:
 # Configuration parameters: AllowedMethods, AllowedPatterns, Max.
 Metrics/CyclomaticComplexity:
   Exclude:
+    - 'lib/solargraph/api_map.rb'
     - 'lib/solargraph/api_map/source_to_yard.rb'
     - 'lib/solargraph/complex_type.rb'
     - 'lib/solargraph/parser/parser_gem/node_chainer.rb'
@@ -778,14 +735,12 @@ Metrics/MethodLength:
     - 'lib/solargraph/parser/parser_gem/node_chainer.rb'
     - 'lib/solargraph/source/chain/call.rb'
     - 'lib/solargraph/source_map/mapper.rb'
-    - 'lib/solargraph/type_checker.rb'
 
 # Configuration parameters: CountComments, Max, CountAsOne.
 Metrics/ModuleLength:
   Exclude:
     - 'lib/solargraph/complex_type/type_methods.rb'
     - 'lib/solargraph/parser/parser_gem/node_methods.rb'
-    - 'lib/solargraph/pin_cache.rb'
 
 # Configuration parameters: Max, CountKeywordArgs, MaxOptionalParameters.
 Metrics/ParameterLists:
@@ -832,7 +787,6 @@ Naming/MemoizedInstanceVariableName:
     - 'lib/solargraph/convention/gemfile.rb'
     - 'lib/solargraph/convention/gemspec.rb'
     - 'lib/solargraph/convention/rakefile.rb'
-    - 'lib/solargraph/doc_map.rb'
     - 'lib/solargraph/rbs_map.rb'
     - 'lib/solargraph/workspace.rb'
 
@@ -886,7 +840,6 @@ Naming/VariableName:
 RSpec/Be:
   Exclude:
     - 'spec/rbs_map/stdlib_map_spec.rb'
-    - 'spec/rbs_map_spec.rb'
     - 'spec/source/source_chainer_spec.rb'
 
 # This cop supports unsafe autocorrection (--autocorrect-all).
@@ -909,7 +862,6 @@ RSpec/BeforeAfterAll:
     - '**/spec/rails_helper.rb'
     - '**/spec/support/**/*.rb'
     - 'spec/api_map_spec.rb'
-    - 'spec/doc_map_spec.rb'
     - 'spec/language_server/host/dispatch_spec.rb'
     - 'spec/language_server/protocol_spec.rb'
 
@@ -922,10 +874,6 @@ RSpec/ContextWording:
     - 'spec/pin/method_spec.rb'
     - 'spec/pin/parameter_spec.rb'
     - 'spec/pin/symbol_spec.rb'
-    - 'spec/type_checker/levels/normal_spec.rb'
-    - 'spec/type_checker/levels/strict_spec.rb'
-    - 'spec/type_checker/levels/strong_spec.rb'
-    - 'spec/type_checker/levels/typed_spec.rb'
 
 # Configuration parameters: IgnoredMetadata.
 RSpec/DescribeClass:
@@ -946,7 +894,6 @@ RSpec/DescribedClass:
     - 'spec/api_map/cache_spec.rb'
     - 'spec/api_map/source_to_yard_spec.rb'
     - 'spec/api_map/store_spec.rb'
-    - 'spec/api_map_spec.rb'
     - 'spec/diagnostics/base_spec.rb'
     - 'spec/diagnostics/require_not_found_spec.rb'
     - 'spec/diagnostics/rubocop_helpers_spec.rb'
@@ -955,7 +902,6 @@ RSpec/DescribedClass:
     - 'spec/diagnostics/update_errors_spec.rb'
     - 'spec/diagnostics_spec.rb'
     - 'spec/doc_map_spec.rb'
-    - 'spec/gem_pins_spec.rb'
     - 'spec/language_server/host/diagnoser_spec.rb'
     - 'spec/language_server/host/dispatch_spec.rb'
     - 'spec/language_server/host/message_worker_spec.rb'
@@ -1004,7 +950,6 @@ RSpec/DescribedClass:
     - 'spec/source_map/mapper_spec.rb'
     - 'spec/source_map_spec.rb'
     - 'spec/source_spec.rb'
-    - 'spec/type_checker/checks_spec.rb'
     - 'spec/type_checker/levels/normal_spec.rb'
     - 'spec/type_checker/levels/strict_spec.rb'
     - 'spec/type_checker/rules_spec.rb'
@@ -1015,7 +960,6 @@ RSpec/DescribedClass:
     - 'spec/yard_map/mapper_spec.rb'
 
 # This cop supports unsafe autocorrection (--autocorrect-all).
-# Configuration parameters: AutoCorrect.
 RSpec/EmptyExampleGroup:
   Exclude:
     - 'spec/convention_spec.rb'
@@ -1060,7 +1004,6 @@ RSpec/ExampleLength:
 # DisallowedExamples: works
 RSpec/ExampleWording:
   Exclude:
-    - 'spec/convention/struct_definition_spec.rb'
     - 'spec/pin/base_spec.rb'
     - 'spec/pin/method_spec.rb'
 
@@ -1101,7 +1044,6 @@ RSpec/ImplicitExpect:
 RSpec/InstanceVariable:
   Exclude:
     - 'spec/api_map/config_spec.rb'
-    - 'spec/api_map_spec.rb'
     - 'spec/diagnostics/require_not_found_spec.rb'
     - 'spec/language_server/host/dispatch_spec.rb'
     - 'spec/language_server/host_spec.rb'
@@ -1117,16 +1059,10 @@ RSpec/LeakyConstantDeclaration:
     - 'spec/complex_type_spec.rb'
 
 # This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: AutoCorrect.
 RSpec/LetBeforeExamples:
   Exclude:
     - 'spec/complex_type_spec.rb'
 
-# Configuration parameters: .
-# SupportedStyles: have_received, receive
-RSpec/MessageSpies:
-  EnforcedStyle: receive
-
 RSpec/MissingExampleGroupArgument:
   Exclude:
     - 'spec/diagnostics/rubocop_helpers_spec.rb'
@@ -1145,8 +1081,6 @@ RSpec/MultipleExpectations:
     - 'spec/diagnostics/type_check_spec.rb'
     - 'spec/diagnostics/update_errors_spec.rb'
     - 'spec/diagnostics_spec.rb'
-    - 'spec/doc_map_spec.rb'
-    - 'spec/gem_pins_spec.rb'
     - 'spec/language_server/host/message_worker_spec.rb'
     - 'spec/language_server/host_spec.rb'
     - 'spec/language_server/message/completion_item/resolve_spec.rb'
@@ -1173,7 +1107,6 @@ RSpec/MultipleExpectations:
     - 'spec/rbs_map/core_map_spec.rb'
     - 'spec/rbs_map/stdlib_map_spec.rb'
     - 'spec/rbs_map_spec.rb'
-    - 'spec/shell_spec.rb'
     - 'spec/source/chain/call_spec.rb'
     - 'spec/source/chain/class_variable_spec.rb'
     - 'spec/source/chain/global_variable_spec.rb'
@@ -1187,7 +1120,6 @@ RSpec/MultipleExpectations:
     - 'spec/source_map/node_processor_spec.rb'
     - 'spec/source_map_spec.rb'
     - 'spec/source_spec.rb'
-    - 'spec/type_checker/checks_spec.rb'
     - 'spec/type_checker/levels/normal_spec.rb'
     - 'spec/type_checker/levels/strict_spec.rb'
     - 'spec/type_checker/levels/strong_spec.rb'
@@ -1198,6 +1130,11 @@ RSpec/MultipleExpectations:
     - 'spec/yard_map/mapper/to_method_spec.rb'
     - 'spec/yard_map/mapper_spec.rb'
 
+# Configuration parameters: AllowSubject, Max.
+RSpec/MultipleMemoizedHelpers:
+  Exclude:
+    - 'spec/shell_spec.rb'
+
 # Configuration parameters: Max, AllowedGroups.
 RSpec/NestedGroups:
   Exclude:
@@ -1212,7 +1149,6 @@ RSpec/NoExpectationExample:
     - 'spec/pin/block_spec.rb'
     - 'spec/pin/method_spec.rb'
     - 'spec/source/chain/call_spec.rb'
-    - 'spec/type_checker/checks_spec.rb'
     - 'spec/type_checker/levels/typed_spec.rb'
 
 # This cop supports safe autocorrection (--autocorrect).
@@ -1220,7 +1156,6 @@ RSpec/NoExpectationExample:
 # SupportedStyles: not_to, to_not
 RSpec/NotToNot:
   Exclude:
-    - 'spec/api_map_spec.rb'
     - 'spec/rbs_map/core_map_spec.rb'
 
 RSpec/PendingWithoutReason:
@@ -1256,7 +1191,6 @@ RSpec/RemoveConst:
 
 RSpec/RepeatedDescription:
   Exclude:
-    - 'spec/api_map_spec.rb'
     - 'spec/language_server/protocol_spec.rb'
     - 'spec/parser/node_methods_spec.rb'
     - 'spec/source/chain/call_spec.rb'
@@ -1275,112 +1209,10 @@ RSpec/RepeatedExample:
     - 'spec/type_checker/levels/strict_spec.rb'
 
 # This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: AutoCorrect.
 RSpec/ScatteredLet:
   Exclude:
     - 'spec/complex_type_spec.rb'
 
-# Configuration parameters: Include, CustomTransform, IgnoreMethods, IgnoreMetadata.
-# Include: **/*_spec.rb
-RSpec/SpecFilePathFormat:
-  Exclude:
-    - '**/spec/routing/**/*'
-    - 'spec/api_map/cache_spec.rb'
-    - 'spec/api_map/config_spec.rb'
-    - 'spec/api_map/source_to_yard_spec.rb'
-    - 'spec/api_map/store_spec.rb'
-    - 'spec/api_map_spec.rb'
-    - 'spec/convention/activesupport_concern_spec.rb'
-    - 'spec/convention/struct_definition_spec.rb'
-    - 'spec/convention_spec.rb'
-    - 'spec/diagnostics/base_spec.rb'
-    - 'spec/diagnostics/require_not_found_spec.rb'
-    - 'spec/diagnostics/rubocop_helpers_spec.rb'
-    - 'spec/diagnostics/rubocop_spec.rb'
-    - 'spec/diagnostics/type_check_spec.rb'
-    - 'spec/diagnostics/update_errors_spec.rb'
-    - 'spec/diagnostics_spec.rb'
-    - 'spec/doc_map_spec.rb'
-    - 'spec/gem_pins_spec.rb'
-    - 'spec/language_server/host/diagnoser_spec.rb'
-    - 'spec/language_server/host/dispatch_spec.rb'
-    - 'spec/language_server/host/message_worker_spec.rb'
-    - 'spec/language_server/host_spec.rb'
-    - 'spec/language_server/message/completion_item/resolve_spec.rb'
-    - 'spec/language_server/message/extended/check_gem_version_spec.rb'
-    - 'spec/language_server/message/initialize_spec.rb'
-    - 'spec/language_server/message/text_document/definition_spec.rb'
-    - 'spec/language_server/message/text_document/formatting_spec.rb'
-    - 'spec/language_server/message/text_document/hover_spec.rb'
-    - 'spec/language_server/message/text_document/rename_spec.rb'
-    - 'spec/language_server/message/text_document/type_definition_spec.rb'
-    - 'spec/language_server/message/workspace/did_change_configuration_spec.rb'
-    - 'spec/language_server/message/workspace/did_change_watched_files_spec.rb'
-    - 'spec/language_server/message_spec.rb'
-    - 'spec/language_server/transport/adapter_spec.rb'
-    - 'spec/language_server/transport/data_reader_spec.rb'
-    - 'spec/language_server/uri_helpers_spec.rb'
-    - 'spec/library_spec.rb'
-    - 'spec/logging_spec.rb'
-    - 'spec/parser/flow_sensitive_typing_spec.rb'
-    - 'spec/parser/node_methods_spec.rb'
-    - 'spec/parser/node_processor_spec.rb'
-    - 'spec/parser_spec.rb'
-    - 'spec/pin/base_spec.rb'
-    - 'spec/pin/base_variable_spec.rb'
-    - 'spec/pin/block_spec.rb'
-    - 'spec/pin/constant_spec.rb'
-    - 'spec/pin/delegated_method_spec.rb'
-    - 'spec/pin/documenting_spec.rb'
-    - 'spec/pin/instance_variable_spec.rb'
-    - 'spec/pin/keyword_spec.rb'
-    - 'spec/pin/local_variable_spec.rb'
-    - 'spec/pin/method_spec.rb'
-    - 'spec/pin/namespace_spec.rb'
-    - 'spec/pin/parameter_spec.rb'
-    - 'spec/pin/search_spec.rb'
-    - 'spec/pin/symbol_spec.rb'
-    - 'spec/position_spec.rb'
-    - 'spec/rbs_map/conversions_spec.rb'
-    - 'spec/rbs_map/core_map_spec.rb'
-    - 'spec/rbs_map/stdlib_map_spec.rb'
-    - 'spec/rbs_map_spec.rb'
-    - 'spec/shell_spec.rb'
-    - 'spec/source/chain/array_spec.rb'
-    - 'spec/source/chain/call_spec.rb'
-    - 'spec/source/chain/class_variable_spec.rb'
-    - 'spec/source/chain/constant_spec.rb'
-    - 'spec/source/chain/global_variable_spec.rb'
-    - 'spec/source/chain/head_spec.rb'
-    - 'spec/source/chain/instance_variable_spec.rb'
-    - 'spec/source/chain/link_spec.rb'
-    - 'spec/source/chain/literal_spec.rb'
-    - 'spec/source/chain/z_super_spec.rb'
-    - 'spec/source/chain_spec.rb'
-    - 'spec/source/change_spec.rb'
-    - 'spec/source/cursor_spec.rb'
-    - 'spec/source/source_chainer_spec.rb'
-    - 'spec/source/updater_spec.rb'
-    - 'spec/source_map/clip_spec.rb'
-    - 'spec/source_map/mapper_spec.rb'
-    - 'spec/source_map_spec.rb'
-    - 'spec/source_spec.rb'
-    - 'spec/type_checker/checks_spec.rb'
-    - 'spec/type_checker/levels/normal_spec.rb'
-    - 'spec/type_checker/levels/strict_spec.rb'
-    - 'spec/type_checker/levels/strong_spec.rb'
-    - 'spec/type_checker/levels/typed_spec.rb'
-    - 'spec/type_checker/rules_spec.rb'
-    - 'spec/type_checker_spec.rb'
-    - 'spec/workspace/config_spec.rb'
-    - 'spec/workspace_spec.rb'
-    - 'spec/yard_map/mapper/to_method_spec.rb'
-    - 'spec/yard_map/mapper_spec.rb'
-
-RSpec/StubbedMock:
-  Exclude:
-    - 'spec/language_server/host/message_worker_spec.rb'
-
 # Configuration parameters: IgnoreNameless, IgnoreSymbolicNames.
 RSpec/VerifiedDoubles:
   Exclude:
@@ -1436,7 +1268,6 @@ Style/AccessorGrouping:
 # SupportedStyles: always, conditionals
 Style/AndOr:
   Exclude:
-    - 'lib/solargraph/api_map/source_to_yard.rb'
     - 'lib/solargraph/complex_type/unique_type.rb'
     - 'lib/solargraph/language_server/message/base.rb'
     - 'lib/solargraph/page.rb'
@@ -1625,7 +1456,6 @@ Style/Documentation:
     - 'lib/solargraph/parser.rb'
     - 'lib/solargraph/parser/comment_ripper.rb'
     - 'lib/solargraph/parser/flow_sensitive_typing.rb'
-    - 'lib/solargraph/parser/node_methods.rb'
     - 'lib/solargraph/parser/node_processor/base.rb'
     - 'lib/solargraph/parser/parser_gem.rb'
     - 'lib/solargraph/parser/parser_gem/class_methods.rb'
@@ -1711,7 +1541,7 @@ Style/EmptyLambdaParameter:
     - 'spec/rbs_map/core_map_spec.rb'
 
 # This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: AutoCorrect, EnforcedStyle.
+# Configuration parameters: EnforcedStyle.
 # SupportedStyles: compact, expanded
 Style/EmptyMethod:
   Exclude:
@@ -1766,7 +1596,6 @@ Style/FrozenStringLiteralComment:
     - 'lib/solargraph/parser.rb'
     - 'lib/solargraph/parser/comment_ripper.rb'
     - 'lib/solargraph/parser/flow_sensitive_typing.rb'
-    - 'lib/solargraph/parser/node_methods.rb'
     - 'lib/solargraph/parser/parser_gem.rb'
     - 'lib/solargraph/parser/snippet.rb'
     - 'lib/solargraph/pin/breakable.rb'
@@ -1779,7 +1608,6 @@ Style/FrozenStringLiteralComment:
     - 'spec/api_map/cache_spec.rb'
     - 'spec/api_map/config_spec.rb'
     - 'spec/api_map/source_to_yard_spec.rb'
-    - 'spec/api_map_spec.rb'
     - 'spec/complex_type_spec.rb'
     - 'spec/convention/struct_definition_spec.rb'
     - 'spec/convention_spec.rb'
@@ -1851,7 +1679,6 @@ Style/FrozenStringLiteralComment:
     - 'spec/rbs_map/core_map_spec.rb'
     - 'spec/rbs_map/stdlib_map_spec.rb'
     - 'spec/rbs_map_spec.rb'
-    - 'spec/shell_spec.rb'
     - 'spec/source/chain/array_spec.rb'
     - 'spec/source/chain/call_spec.rb'
     - 'spec/source/chain/class_variable_spec.rb'
@@ -1873,7 +1700,6 @@ Style/FrozenStringLiteralComment:
     - 'spec/source_map_spec.rb'
     - 'spec/source_spec.rb'
     - 'spec/spec_helper.rb'
-    - 'spec/type_checker/checks_spec.rb'
     - 'spec/type_checker/levels/normal_spec.rb'
     - 'spec/type_checker/levels/strict_spec.rb'
     - 'spec/type_checker/levels/strong_spec.rb'
@@ -1900,7 +1726,6 @@ Style/GuardClause:
     - 'lib/solargraph/api_map.rb'
     - 'lib/solargraph/library.rb'
     - 'lib/solargraph/parser/parser_gem/node_processors/send_node.rb'
-    - 'lib/solargraph/pin_cache.rb'
     - 'lib/solargraph/range.rb'
     - 'lib/solargraph/rbs_map/conversions.rb'
     - 'lib/solargraph/source.rb'
@@ -1950,23 +1775,17 @@ Style/IfInsideElse:
 # This cop supports safe autocorrection (--autocorrect).
 Style/IfUnlessModifier:
   Exclude:
-    - 'lib/solargraph/api_map.rb'
-    - 'lib/solargraph/api_map/index.rb'
     - 'lib/solargraph/complex_type.rb'
     - 'lib/solargraph/complex_type/unique_type.rb'
-    - 'lib/solargraph/doc_map.rb'
     - 'lib/solargraph/language_server/message/completion_item/resolve.rb'
     - 'lib/solargraph/language_server/message/initialize.rb'
     - 'lib/solargraph/language_server/message/text_document/completion.rb'
     - 'lib/solargraph/language_server/message/text_document/hover.rb'
-    - 'lib/solargraph/library.rb'
-    - 'lib/solargraph/parser/parser_gem/class_methods.rb'
     - 'lib/solargraph/parser/parser_gem/node_chainer.rb'
     - 'lib/solargraph/parser/parser_gem/node_methods.rb'
     - 'lib/solargraph/parser/parser_gem/node_processors/sclass_node.rb'
     - 'lib/solargraph/pin/base.rb'
     - 'lib/solargraph/pin/callable.rb'
-    - 'lib/solargraph/pin/common.rb'
     - 'lib/solargraph/pin/constant.rb'
     - 'lib/solargraph/pin/method.rb'
     - 'lib/solargraph/pin/parameter.rb'
@@ -1981,7 +1800,6 @@ Style/IfUnlessModifier:
     - 'lib/solargraph/source_map/clip.rb'
     - 'lib/solargraph/source_map/mapper.rb'
     - 'lib/solargraph/type_checker.rb'
-    - 'lib/solargraph/workspace.rb'
     - 'lib/solargraph/workspace/config.rb'
     - 'lib/solargraph/yard_map/helpers.rb'
     - 'lib/solargraph/yard_map/mapper/to_method.rb'
@@ -1998,7 +1816,6 @@ Style/MapIntoArray:
   Exclude:
     - 'lib/solargraph/diagnostics/update_errors.rb'
     - 'lib/solargraph/parser/parser_gem/node_chainer.rb'
-    - 'lib/solargraph/type_checker/param_def.rb'
 
 # This cop supports unsafe autocorrection (--autocorrect-all).
 Style/MapToHash:
@@ -2031,7 +1848,6 @@ Style/MethodDefParentheses:
     - 'lib/solargraph/convention/struct_definition/struct_assignment_node.rb'
     - 'lib/solargraph/convention/struct_definition/struct_definition_node.rb'
     - 'lib/solargraph/diagnostics/rubocop_helpers.rb'
-    - 'lib/solargraph/doc_map.rb'
     - 'lib/solargraph/equality.rb'
     - 'lib/solargraph/gem_pins.rb'
     - 'lib/solargraph/language_server/host/message_worker.rb'
@@ -2040,7 +1856,6 @@ Style/MethodDefParentheses:
     - 'lib/solargraph/location.rb'
     - 'lib/solargraph/parser/comment_ripper.rb'
     - 'lib/solargraph/parser/flow_sensitive_typing.rb'
-    - 'lib/solargraph/parser/node_methods.rb'
     - 'lib/solargraph/parser/node_processor/base.rb'
     - 'lib/solargraph/parser/parser_gem/flawed_builder.rb'
     - 'lib/solargraph/parser/parser_gem/node_chainer.rb'
@@ -2066,9 +1881,7 @@ Style/MethodDefParentheses:
     - 'lib/solargraph/source_map.rb'
     - 'lib/solargraph/source_map/mapper.rb'
     - 'lib/solargraph/type_checker.rb'
-    - 'lib/solargraph/type_checker/checks.rb'
     - 'lib/solargraph/yard_map/helpers.rb'
-    - 'lib/solargraph/yardoc.rb'
     - 'spec/doc_map_spec.rb'
     - 'spec/fixtures/rdoc-lib/lib/example.rb'
     - 'spec/source_map_spec.rb'
@@ -2076,7 +1889,6 @@ Style/MethodDefParentheses:
     - 'spec/type_checker/levels/normal_spec.rb'
     - 'spec/type_checker/levels/strict_spec.rb'
     - 'spec/type_checker/levels/strong_spec.rb'
-    - 'spec/type_checker/levels/typed_spec.rb'
 
 Style/MultilineBlockChain:
   Exclude:
@@ -2135,13 +1947,6 @@ Style/NegatedIfElseCondition:
     - 'lib/solargraph/shell.rb'
     - 'lib/solargraph/type_checker.rb'
 
-# This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: AllowedMethods.
-# AllowedMethods: be, be_a, be_an, be_between, be_falsey, be_kind_of, be_instance_of, be_truthy, be_within, eq, eql, end_with, include, match, raise_error, respond_to, start_with
-Style/NestedParenthesizedCalls:
-  Exclude:
-    - 'lib/solargraph/type_checker.rb'
-
 # This cop supports safe autocorrection (--autocorrect).
 Style/NestedTernaryOperator:
   Exclude:
@@ -2156,7 +1961,6 @@ Style/Next:
     - 'lib/solargraph/parser/parser_gem/node_processors/send_node.rb'
     - 'lib/solargraph/pin/signature.rb'
     - 'lib/solargraph/source_map/clip.rb'
-    - 'lib/solargraph/type_checker/checks.rb'
 
 # This cop supports safe autocorrection (--autocorrect).
 # Configuration parameters: MinDigits, Strict, AllowedNumbers, AllowedPatterns.
@@ -2237,7 +2041,7 @@ Style/RedundantBegin:
     - 'lib/solargraph/shell.rb'
     - 'lib/solargraph/source/cursor.rb'
     - 'lib/solargraph/source/encoding_fixes.rb'
-    - 'lib/solargraph/type_checker.rb'
+    - 'lib/solargraph/source_map/mapper.rb'
     - 'lib/solargraph/workspace.rb'
 
 # This cop supports safe autocorrection (--autocorrect).
@@ -2251,16 +2055,9 @@ Style/RedundantFreeze:
     - 'lib/solargraph/complex_type.rb'
     - 'lib/solargraph/source_map/mapper.rb'
 
-# This cop supports unsafe autocorrection (--autocorrect-all).
-# Configuration parameters: AutoCorrect, AllowComments.
-Style/RedundantInitialize:
-  Exclude:
-    - 'lib/solargraph/rbs_map/core_map.rb'
-
 # This cop supports unsafe autocorrection (--autocorrect-all).
 Style/RedundantInterpolation:
   Exclude:
-    - 'lib/solargraph/api_map/store.rb'
     - 'lib/solargraph/parser/parser_gem/node_chainer.rb'
     - 'lib/solargraph/source_map/mapper.rb'
 
@@ -2284,13 +2081,24 @@ Style/RedundantRegexpArgument:
     - 'spec/diagnostics/rubocop_spec.rb'
     - 'spec/language_server/host_spec.rb'
 
+# This cop supports safe autocorrection (--autocorrect).
+Style/RedundantRegexpCharacterClass:
+  Exclude:
+    - 'lib/solargraph/source/cursor.rb'
+    - 'lib/solargraph/source/source_chainer.rb'
+
 # This cop supports safe autocorrection (--autocorrect).
 Style/RedundantRegexpEscape:
   Exclude:
     - 'lib/solargraph/complex_type.rb'
     - 'lib/solargraph/diagnostics/rubocop.rb'
     - 'lib/solargraph/language_server/uri_helpers.rb'
+    - 'lib/solargraph/parser/parser_gem/node_methods.rb'
+    - 'lib/solargraph/pin/method.rb'
+    - 'lib/solargraph/pin/parameter.rb'
     - 'lib/solargraph/shell.rb'
+    - 'lib/solargraph/source/change.rb'
+    - 'lib/solargraph/source/cursor.rb'
     - 'lib/solargraph/source_map/clip.rb'
     - 'lib/solargraph/source_map/mapper.rb'
 
@@ -2300,7 +2108,6 @@ Style/RedundantReturn:
   Exclude:
     - 'lib/solargraph/api_map.rb'
     - 'lib/solargraph/complex_type/type_methods.rb'
-    - 'lib/solargraph/doc_map.rb'
     - 'lib/solargraph/parser/parser_gem/node_methods.rb'
     - 'lib/solargraph/source/chain/z_super.rb'
 
@@ -2337,7 +2144,6 @@ Style/RescueStandardError:
 Style/SafeNavigation:
   Exclude:
     - 'lib/solargraph/api_map/index.rb'
-    - 'lib/solargraph/doc_map.rb'
     - 'lib/solargraph/language_server/message/completion_item/resolve.rb'
     - 'lib/solargraph/language_server/request.rb'
     - 'lib/solargraph/language_server/transport/data_reader.rb'
@@ -2345,15 +2151,9 @@ Style/SafeNavigation:
     - 'lib/solargraph/pin/base.rb'
     - 'lib/solargraph/pin/conversions.rb'
     - 'lib/solargraph/pin/method.rb'
-    - 'lib/solargraph/pin_cache.rb'
     - 'lib/solargraph/range.rb'
     - 'lib/solargraph/type_checker.rb'
 
-# Configuration parameters: Max.
-Style/SafeNavigationChainLength:
-  Exclude:
-    - 'lib/solargraph/doc_map.rb'
-
 # This cop supports unsafe autocorrection (--autocorrect-all).
 Style/SlicingWithRange:
   Exclude:
@@ -2374,7 +2174,6 @@ Style/SlicingWithRange:
     - 'lib/solargraph/source/cursor.rb'
     - 'lib/solargraph/source/source_chainer.rb'
     - 'lib/solargraph/source_map/mapper.rb'
-    - 'lib/solargraph/type_checker/checks.rb'
 
 # This cop supports safe autocorrection (--autocorrect).
 # Configuration parameters: AllowModifier.
@@ -2418,7 +2217,6 @@ Style/StringLiterals:
     - 'lib/solargraph/complex_type.rb'
     - 'lib/solargraph/complex_type/unique_type.rb'
     - 'lib/solargraph/convention/struct_definition.rb'
-    - 'lib/solargraph/doc_map.rb'
     - 'lib/solargraph/language_server/host.rb'
     - 'lib/solargraph/language_server/message/extended/document_gems.rb'
     - 'lib/solargraph/language_server/message/extended/download_core.rb'
@@ -2619,7 +2417,6 @@ Style/WordArray:
     - 'spec/pin/method_spec.rb'
     - 'spec/source/cursor_spec.rb'
     - 'spec/source/source_chainer_spec.rb'
-    - 'spec/source_map/clip_spec.rb'
     - 'spec/source_map/mapper_spec.rb'
     - 'spec/source_map_spec.rb'
     - 'spec/source_spec.rb'
@@ -2653,7 +2450,6 @@ YARD/MismatchName:
   Exclude:
     - 'lib/solargraph/complex_type.rb'
     - 'lib/solargraph/complex_type/unique_type.rb'
-    - 'lib/solargraph/gem_pins.rb'
     - 'lib/solargraph/language_server/host.rb'
     - 'lib/solargraph/language_server/host/dispatch.rb'
     - 'lib/solargraph/language_server/request.rb'
@@ -2674,7 +2470,6 @@ YARD/MismatchName:
     - 'lib/solargraph/pin/until.rb'
     - 'lib/solargraph/pin/while.rb'
     - 'lib/solargraph/pin_cache.rb'
-    - 'lib/solargraph/source/chain.rb'
     - 'lib/solargraph/source/chain/call.rb'
     - 'lib/solargraph/source/chain/z_super.rb'
     - 'lib/solargraph/type_checker.rb'
@@ -2696,7 +2491,6 @@ Layout/LineLength:
     - 'lib/solargraph/complex_type.rb'
     - 'lib/solargraph/complex_type/unique_type.rb'
     - 'lib/solargraph/convention/data_definition.rb'
-    - 'lib/solargraph/doc_map.rb'
     - 'lib/solargraph/gem_pins.rb'
     - 'lib/solargraph/language_server/host.rb'
     - 'lib/solargraph/language_server/message/extended/check_gem_version.rb'
@@ -2721,7 +2515,6 @@ Layout/LineLength:
     - 'lib/solargraph/parser/parser_gem/node_processors/send_node.rb'
     - 'lib/solargraph/pin/base.rb'
     - 'lib/solargraph/pin/callable.rb'
-    - 'lib/solargraph/pin/common.rb'
     - 'lib/solargraph/pin/documenting.rb'
     - 'lib/solargraph/pin/method.rb'
     - 'lib/solargraph/pin/parameter.rb'
@@ -2741,10 +2534,8 @@ Layout/LineLength:
     - 'lib/solargraph/source_map/clip.rb'
     - 'lib/solargraph/source_map/mapper.rb'
     - 'lib/solargraph/type_checker.rb'
-    - 'lib/solargraph/workspace.rb'
     - 'lib/solargraph/workspace/config.rb'
     - 'lib/solargraph/yard_map/mapper/to_method.rb'
-    - 'spec/api_map_spec.rb'
     - 'spec/complex_type_spec.rb'
     - 'spec/language_server/message/completion_item/resolve_spec.rb'
     - 'spec/language_server/message/extended/check_gem_version_spec.rb'
@@ -2754,4 +2545,3 @@ Layout/LineLength:
     - 'spec/source/chain_spec.rb'
     - 'spec/source_map/clip_spec.rb'
     - 'spec/source_map_spec.rb'
-    - 'spec/workspace_spec.rb'
diff --git a/Gemfile b/Gemfile
index 3a5ae2b84..2da498052 100755
--- a/Gemfile
+++ b/Gemfile
@@ -2,6 +2,9 @@ source 'https://rubygems.org'
 
 gemspec name: 'solargraph'
 
+# allow rubocop-yard to understand literal symbols in type annotations
+gem 'yard', github: 'apiology/yard', branch: 'literal_symbols', require: false
+
 # Local gemfile for development tools, etc.
 local_gemfile = File.expand_path(".Gemfile", __dir__)
 instance_eval File.read local_gemfile if File.exist? local_gemfile
diff --git a/README.md b/README.md
index 3e94a60b9..f1b704bed 100755
--- a/README.md
+++ b/README.md
@@ -51,6 +51,8 @@ Plug-ins and extensions are available for the following editors:
 
 Solargraph's behavior can be controlled via optional [configuration](https://solargraph.org/guides/configuration) files. The highest priority file is a `.solargraph.yml` file at the root of the project. If not present, any global configuration at `~/.config/solargraph/config.yml` will apply. The path to the global configuration can be overridden with the `SOLARGRAPH_GLOBAL_CONFIG` environment variable.
 
+Use `bundle exec solargraph init` to create a configuration file.
+
 ### Plugins
 
 Solargraph supports [plugins](https://solargraph.org/guides/plugins) that implement their own Solargraph features, such as diagnostics reporters and conventions to provide LSP features and type-checking, e.g. for frameworks which use metaprogramming and/or DSLs.
diff --git a/Rakefile b/Rakefile
index d731fc786..2e3f2bed0 100755
--- a/Rakefile
+++ b/Rakefile
@@ -9,7 +9,8 @@ task :console do
 end
 
 desc "Run the type checker"
-task typecheck: [:typecheck_typed]
+
+task typecheck: [:typecheck_strong]
 
 desc "Run the type checker at typed level - return code issues provable without annotations being correct"
 task :typecheck_typed do
@@ -133,5 +134,5 @@ end
 desc "Show quality checks on this development branch so far, including any staged files"
 task :overcommit do
   # OVERCOMMIT_DEBUG=1 will show more detail
-  sh 'SOLARGRAPH_ASSERTS=on bundle exec overcommit --run --diff origin/master'
+  sh 'SOLARGRAPH_ASSERTS=on bundle exec overcommit --run --diff origin/2025-07-02'
 end
diff --git a/lib/solargraph.rb b/lib/solargraph.rb
index 038e7bccf..5aa391422 100755
--- a/lib/solargraph.rb
+++ b/lib/solargraph.rb
@@ -55,8 +55,7 @@ class InvalidRubocopVersionError < RuntimeError;  end
 
   CHDIR_MUTEX = Mutex.new
 
-  # @param type [Symbol] Type of assert.
-  def self.asserts_on?(type)
+  def self.asserts_on?
     if ENV['SOLARGRAPH_ASSERTS'].nil? || ENV['SOLARGRAPH_ASSERTS'].empty?
       false
     elsif ENV['SOLARGRAPH_ASSERTS'] == 'on'
@@ -72,7 +71,26 @@ def self.asserts_on?(type)
   # @param block [Proc] A block that returns a message to log
   # @return [void]
   def self.assert_or_log(type, msg = nil, &block)
-    raise (msg || block.call) if asserts_on?(type) && ![:combine_with_visibility].include?(type)
+    if asserts_on?
+      # @type [String, nil]
+      msg ||= block.call
+
+      raise "No message given for #{type.inspect}" if msg.nil?
+
+      # @todo :combine_with_visibility is not ready for prime time -
+      #  lots of disagreements found in practice that heuristics need
+      #  to be created for and/or debugging needs to resolve in pin
+      #  generation.
+      # @todo :api_map_namespace_pin_stack triggers in a badly handled
+      #   self type case - 'keeps track of self type in method
+      #   parameters in subclass' in call_spec.rb
+      return if %i[api_map_namespace_pin_stack combine_with_visibility].include?(type)
+
+      # conditional aliases to handle compatibility corner cases
+      return if type == :alias_target_missing && msg.include?('highline/compatibility.rb')
+      return if type == :alias_target_missing && msg.include?('lib/json/add/date.rb')
+      raise msg
+    end
     logger.info msg, &block
   end
 
diff --git a/lib/solargraph/api_map.rb b/lib/solargraph/api_map.rb
index eed02b4ef..4cd1cd121 100755
--- a/lib/solargraph/api_map.rb
+++ b/lib/solargraph/api_map.rb
@@ -22,6 +22,9 @@ class ApiMap
     # @return [Array<String>]
     attr_reader :missing_docs
 
+    # @return [Solargraph::Workspace::Gemspecs]
+    attr_reader :gemspecs
+
     # @param pins [Array<Solargraph::Pin::Base>]
     def initialize pins: []
       @source_map_hash = {}
@@ -30,6 +33,12 @@ def initialize pins: []
       index pins
     end
 
+    # @param out [IO, nil] output stream for logging
+    # @return [void]
+    def self.reset_core out: nil
+      @@core_map = RbsMap::CoreMap.new
+    end
+
     #
     # This is a mutable object, which is cached in the Chain class -
     # if you add any fields which change the results of calls (not
@@ -37,16 +46,17 @@ def initialize pins: []
     #
 
     # @param other [Object]
-    def eql?(other)
+    def eql? other
       self.class == other.class &&
         equality_fields == other.equality_fields
     end
 
     # @param other [Object]
-    def ==(other)
+    def == other
       self.eql?(other)
     end
 
+    # @return [Integer]
     def hash
       equality_fields.hash
     end
@@ -96,11 +106,12 @@ def catalog bench
       end
       unresolved_requires = (bench.external_requires + implicit.requires + bench.workspace.config.required).to_a.compact.uniq
       recreate_docmap = @unresolved_requires != unresolved_requires ||
-                     @doc_map&.uncached_yard_gemspecs&.any? ||
-                     @doc_map&.uncached_rbs_collection_gemspecs&.any? ||
-                     @doc_map&.rbs_collection_path != bench.workspace.rbs_collection_path
+                        workspace.rbs_collection_path != bench.workspace.rbs_collection_path ||
+                        @doc_map.any_uncached?
+
       if recreate_docmap
-        @doc_map = DocMap.new(unresolved_requires, [], bench.workspace) # @todo Implement gem preferences
+        @doc_map = DocMap.new(unresolved_requires, bench.workspace, out: nil) # @todo Implement gem preferences
+        @gemspecs = @doc_map.workspace.gemspecs
         @unresolved_requires = @doc_map.unresolved_requires
       end
       @cache.clear if store.update(@@core_map.pins, @doc_map.pins, implicit.pins, iced_pins, live_pins)
@@ -115,26 +126,14 @@ def catalog bench
       [self.class, @source_map_hash, implicit, @doc_map, @unresolved_requires]
     end
 
-    # @return [DocMap]
-    def doc_map
-      @doc_map ||= DocMap.new([], [])
-    end
+    # @return [DocMap, nil]
+    attr_reader :doc_map
 
     # @return [::Array<Gem::Specification>]
     def uncached_gemspecs
       @doc_map&.uncached_gemspecs || []
     end
 
-    # @return [::Array<Gem::Specification>]
-    def uncached_rbs_collection_gemspecs
-      @doc_map.uncached_rbs_collection_gemspecs
-    end
-
-    # @return [::Array<Gem::Specification>]
-    def uncached_yard_gemspecs
-      @doc_map.uncached_yard_gemspecs
-    end
-
     # @return [Array<Pin::Base>]
     def core_pins
       @@core_map.pins
@@ -178,6 +177,7 @@ def clip_at filename, position
     # Create an ApiMap with a workspace in the specified directory.
     #
     # @param directory [String]
+    #
     # @return [ApiMap]
     def self.load directory
       api_map = new
@@ -191,8 +191,8 @@ def self.load directory
 
     # @param out [IO, nil]
     # @return [void]
-    def cache_all!(out)
-      @doc_map.cache_all!(out)
+    def cache_all_for_doc_map! out
+      @doc_map.cache_doc_map_gems!(out)
     end
 
     # @param gemspec [Gem::Specification]
@@ -211,17 +211,17 @@ class << self
     # any missing gems.
     #
     #
-    # @param directory [String]
+    # @param directory [String] workspace directory
     # @param out [IO] The output stream for messages
     # @return [ApiMap]
-    def self.load_with_cache directory, out
+    def self.load_with_cache directory, out = $stderr
       api_map = load(directory)
       if api_map.uncached_gemspecs.empty?
         logger.info { "All gems cached for #{directory}" }
         return api_map
       end
 
-      api_map.cache_all!(out)
+      api_map.cache_all_for_doc_map!(out)
       load(directory)
     end
 
@@ -237,13 +237,6 @@ def keyword_pins
       store.pins_by_class(Pin::Keyword)
     end
 
-    # An array of namespace names defined in the ApiMap.
-    #
-    # @return [Set<String>]
-    def namespaces
-      store.namespaces
-    end
-
     # True if the namespace exists.
     #
     # @param name [String] The namespace to match
@@ -308,12 +301,11 @@ def qualify tag, context_tag = ''
       return unless type
       return tag if type.literal?
 
-      context_type = ComplexType.try_parse(context_tag)
-      return unless context_type
-
       fqns = qualify_namespace(type.rooted_namespace, context_type.rooted_namespace)
       return unless fqns
 
+      return fqns if %w[Class Module].include? type.name
+
       fqns + type.substring
     end
 
@@ -327,7 +319,7 @@ def qualify tag, context_tag = ''
     # @param context_namespace [String] The context namespace in which the
     #   tag was referenced; start from here to resolve the name
     # @return [String, nil] fully qualified namespace
-    def qualify_namespace(namespace, context_namespace = '')
+    def qualify_namespace namespace, context_namespace = ''
       cached = cache.get_qualified_namespace(namespace, context_namespace)
       return cached.clone unless cached.nil?
       result = if namespace.start_with?('::')
@@ -341,13 +333,13 @@ def qualify_namespace(namespace, context_namespace = '')
 
     # @param fqns [String]
     # @return [Array<String>]
-    def get_extends(fqns)
+    def get_extends fqns
       store.get_extends(fqns)
     end
 
     # @param fqns [String]
     # @return [Array<String>]
-    def get_includes(fqns)
+    def get_includes fqns
       store.get_includes(fqns)
     end
 
@@ -357,7 +349,7 @@ def get_includes(fqns)
     # @param namespace [String] A fully qualified namespace
     # @param scope [Symbol] :instance or :class
     # @return [Array<Solargraph::Pin::InstanceVariable>]
-    def get_instance_variable_pins(namespace, scope = :instance)
+    def get_instance_variable_pins namespace, scope = :instance
       result = []
       used = [namespace]
       result.concat store.get_instance_variables(namespace, scope)
@@ -371,6 +363,9 @@ def get_instance_variable_pins(namespace, scope = :instance)
     end
 
     # @see Solargraph::Parser::FlowSensitiveTyping#visible_pins
+    # @param (see Solargraph::Parser::FlowSensitiveTyping#visible_pins)
+    # @return (see Solargraph::Parser::FlowSensitiveTyping#visible_pins)
+    # @sg-ignore Missing @return tag for Solargraph::ApiMap#visible_pins
     def visible_pins(*args, **kwargs, &blk)
       Solargraph::Parser::FlowSensitiveTyping.visible_pins(*args, **kwargs, &blk)
     end
@@ -379,7 +374,7 @@ def visible_pins(*args, **kwargs, &blk)
     #
     # @param namespace [String] A fully qualified namespace
     # @return [Enumerable<Solargraph::Pin::ClassVariable>]
-    def get_class_variable_pins(namespace)
+    def get_class_variable_pins namespace
       prefer_non_nil_variables(store.get_class_variables(namespace))
     end
 
@@ -406,16 +401,18 @@ def get_block_pins
     # @param deep [Boolean] True to include superclasses, mixins, etc.
     # @return [Array<Solargraph::Pin::Method>]
     def get_methods rooted_tag, scope: :instance, visibility: [:public], deep: true
+      rooted_tag = qualify(rooted_tag, '')
+      return [] unless rooted_tag
       if rooted_tag.start_with? 'Array('
         # Array() are really tuples - use our fill, as the RBS repo
         # does not give us definitions for it
         rooted_tag = "Solargraph::Fills::Tuple(#{rooted_tag[6..-2]})"
       end
-      rooted_type = ComplexType.try_parse(rooted_tag)
-      fqns = rooted_type.namespace
-      namespace_pin = store.get_path_pins(fqns).select { |p| p.is_a?(Pin::Namespace) }.first
       cached = cache.get_methods(rooted_tag, scope, visibility, deep)
       return cached.clone unless cached.nil?
+      rooted_type = ComplexType.try_parse(rooted_tag)
+      fqns = rooted_type.namespace
+      namespace_pin = get_namespace_pin(fqns)
       # @type [Array<Solargraph::Pin::Method>]
       result = []
       skip = Set.new
@@ -533,12 +530,23 @@ def get_complex_type_methods complex_type, context = '', internal = false
     # @param name [String] Method name to look up
     # @param scope [Symbol] :instance or :class
     # @param visibility [Array<Symbol>] :public, :protected, and/or :private
-    # @param preserve_generics [Boolean]
+    # @param preserve_generics [Boolean] True to preserve any
+    #   unresolved generic parameters, false to erase them
     # @return [Array<Solargraph::Pin::Method>]
-    def get_method_stack rooted_tag, name, scope: :instance, visibility: [:private, :protected, :public], preserve_generics: false
-      rooted_type = ComplexType.parse(rooted_tag)
+    def get_method_stack rooted_tag, name, scope: :instance, visibility: [:private, :protected, :public],
+                         preserve_generics: false
+      rooted_tag = qualify(rooted_tag, '')
+      return [] unless rooted_tag
+      rooted_type = ComplexType.try_parse(rooted_tag)
+      return [] if rooted_type.nil?
       fqns = rooted_type.namespace
-      namespace_pin = store.get_path_pins(fqns).select { |p| p.is_a?(Pin::Namespace) }.first
+      namespace_pin = get_namespace_pin(fqns)
+      if namespace_pin.nil?
+        # :nocov:
+        Solargraph.assert_or_log(:api_map_namespace_pin_stack, "Could not find namespace pin for #{fqns} while looking for method #{name}")
+        return []
+        # :nocov:
+      end
       methods = get_methods(rooted_tag, scope: scope, visibility: visibility).select { |p| p.name == name }
       methods = erase_generics(namespace_pin, rooted_type, methods) unless preserve_generics
       methods
@@ -549,7 +557,7 @@ def get_method_stack rooted_tag, name, scope: :instance, visibility: [:private,
     # @deprecated Use #get_path_pins instead.
     #
     # @param path [String] The path to find
-    # @return [Enumerable<Solargraph::Pin::Base>]
+    # @return [Array<Solargraph::Pin::Base>]
     def get_path_suggestions path
       return [] if path.nil?
       resolve_method_aliases store.get_path_pins(path)
@@ -558,7 +566,7 @@ def get_path_suggestions path
     # Get an array of pins that match the specified path.
     #
     # @param path [String]
-    # @return [Enumerable<Pin::Base>]
+    # @return [Array<Pin::Base>]
     def get_path_pins path
       get_path_suggestions(path)
     end
@@ -648,7 +656,7 @@ def bundled? filename
     # @param sup [String] The superclass
     # @param sub [String] The subclass
     # @return [Boolean]
-    def super_and_sub?(sup, sub)
+    def super_and_sub? sup, sub
       fqsup = qualify(sup)
       cls = qualify(sub)
       tested = []
@@ -667,7 +675,7 @@ def super_and_sub?(sup, sub)
     # @param module_ns [String] The module namespace (no type parameters)
     #
     # @return [Boolean]
-    def type_include?(host_ns, module_ns)
+    def type_include? host_ns, module_ns
       store.get_includes(host_ns).map { |inc_tag| ComplexType.parse(inc_tag).name }.include?(module_ns)
     end
 
@@ -677,10 +685,15 @@ def type_include?(host_ns, module_ns)
     def resolve_method_aliases pins, visibility = [:public, :private, :protected]
       with_resolved_aliases = pins.map do |pin|
         resolved = resolve_method_alias(pin)
-        next nil if resolved.respond_to?(:visibility) && !visibility.include?(resolved.visibility)
+        if resolved.respond_to?(:visibility) && !visibility.include?(resolved.visibility)
+          Solargraph.assert_or_log(:alias_visibility) { "Rejecting alias - visibility of target is #{resolved.visibility}, looking for visibility #{visibility}" }
+          next nil
+        end
         resolved
       end.compact
-      logger.debug { "ApiMap#resolve_method_aliases(pins=#{pins.map(&:name)}, visibility=#{visibility}) => #{with_resolved_aliases.map(&:name)}" }
+      logger.debug do
+        "ApiMap#resolve_method_aliases(pins=#{pins.map(&:name)}, visibility=#{visibility}) => #{with_resolved_aliases.map(&:name)}"
+      end
       GemPins.combine_method_pins_by_path(with_resolved_aliases)
     end
 
@@ -695,7 +708,7 @@ def resolve_method_aliases pins, visibility = [:public, :private, :protected]
     # @param skip [Set<String>]
     # @param no_core [Boolean] Skip core classes if true
     # @return [Array<Pin::Base>]
-    def inner_get_methods_from_reference(fq_reference_tag, namespace_pin, type, scope, visibility, deep, skip, no_core)
+    def inner_get_methods_from_reference fq_reference_tag, namespace_pin, type, scope, visibility, deep, skip, no_core
       logger.debug { "ApiMap#add_methods_from_reference(type=#{type}) starting" }
 
       # Ensure the types returned by the methods in the referenced
@@ -709,7 +722,7 @@ def inner_get_methods_from_reference(fq_reference_tag, namespace_pin, type, scop
       # @todo Can inner_get_methods be cached?  Lots of lookups of base types going on.
       methods = inner_get_methods(resolved_reference_type.tag, scope, visibility, deep, skip, no_core)
       if namespace_pin && !resolved_reference_type.all_params.empty?
-        reference_pin = store.get_path_pins(resolved_reference_type.name).select { |p| p.is_a?(Pin::Namespace) }.first
+        reference_pin = get_namespace_pin(resolved_reference_type.namespace)
         # logger.debug { "ApiMap#add_methods_from_reference(type=#{type}) - resolving generics with #{reference_pin.generics}, #{resolved_reference_type.rooted_tags}" }
         methods = methods.map do |method_pin|
           method_pin.resolve_generics(reference_pin, resolved_reference_type)
@@ -719,6 +732,11 @@ def inner_get_methods_from_reference(fq_reference_tag, namespace_pin, type, scop
       methods
     end
 
+    # @return [Workspace, nil]
+    def workspace
+      @doc_map&.workspace
+    end
+
     private
 
     # A hash of source maps with filename keys.
@@ -734,6 +752,13 @@ def store
     # @return [Solargraph::ApiMap::Cache]
     attr_reader :cache
 
+    # @param fqns [String]
+    # @return [Pin::Namespace, nil]
+    def get_namespace_pin fqns
+      # fqns = ComplexType.parse(fqns).namespace
+      store.get_path_pins(fqns).select { |p| p.is_a?(Pin::Namespace) }.first
+    end
+
     # @param rooted_tag [String] A fully qualified namespace, with
     #   generic parameter values if applicable
     # @param scope [Symbol] :class or :instance
@@ -743,17 +768,32 @@ def store
     # @param no_core [Boolean] Skip core classes if true
     # @return [Array<Pin::Base>]
     def inner_get_methods rooted_tag, scope, visibility, deep, skip, no_core = false
+      rooted_tag = qualify(rooted_tag, '')
+      return [] if rooted_tag.nil?
+      return [] unless rooted_tag
       rooted_type = ComplexType.parse(rooted_tag).force_rooted
       fqns = rooted_type.namespace
-      fqns_generic_params = rooted_type.all_params
-      namespace_pin = store.get_path_pins(fqns).select { |p| p.is_a?(Pin::Namespace) }.first
+      namespace_pin = get_namespace_pin(fqns)
+      if namespace_pin.nil?
+        # :nocov:
+        Solargraph.assert_or_log(:api_map_namespace_pin_inner, "Could not find namespace pin for #{fqns}")
+        return []
+        # :nocov:
+      end
       return [] if no_core && fqns =~ /^(Object|BasicObject|Class|Module)$/
+      # @todo should this by by rooted_tag_?
       reqstr = "#{fqns}|#{scope}|#{visibility.sort}|#{deep}"
       return [] if skip.include?(reqstr)
       skip.add reqstr
       result = []
+
       environ = Convention.for_object(self, rooted_tag, scope, visibility, deep, skip, no_core)
-      result.concat environ.pins
+      # ensure we start out with any immediate methods in this
+      # namespace so we roughly match the same ordering of get_methods
+      # and obey the 'deep' instruction
+      direct_convention_methods, convention_methods_by_reference = environ.pins.partition { |p| p.namespace == rooted_tag }
+      result.concat direct_convention_methods
+
       if deep && scope == :instance
         store.get_prepends(fqns).reverse.each do |im|
           fqim = qualify(im, fqns)
@@ -767,14 +807,20 @@ def inner_get_methods rooted_tag, scope, visibility, deep, skip, no_core = false
       logger.info { "ApiMap#inner_get_methods(rooted_tag=#{rooted_tag.inspect}, scope=#{scope.inspect}, visibility=#{visibility.inspect}, deep=#{deep.inspect}, skip=#{skip.inspect}, fqns=#{fqns}) - added from store: #{methods}" }
       result.concat methods
       if deep
+        result.concat convention_methods_by_reference
+
         if scope == :instance
           store.get_includes(fqns).reverse.each do |include_tag|
             rooted_include_tag = qualify(include_tag, rooted_tag)
-            result.concat inner_get_methods_from_reference(rooted_include_tag, namespace_pin, rooted_type, scope, visibility, deep, skip, true)
+            if rooted_include_tag
+              result.concat inner_get_methods_from_reference(rooted_include_tag, namespace_pin, rooted_type, scope,
+                                                             visibility, deep, skip, true)
+            end
           end
           rooted_sc_tag = qualify_superclass(rooted_tag)
           unless rooted_sc_tag.nil?
-            result.concat inner_get_methods_from_reference(rooted_sc_tag, namespace_pin, rooted_type, scope, visibility, true, skip, no_core)
+            result.concat inner_get_methods_from_reference(rooted_sc_tag, namespace_pin, rooted_type, scope,
+                                                           visibility, true, skip, no_core)
           end
         else
           logger.info { "ApiMap#inner_get_methods(#{fqns}, #{scope}, #{visibility}, #{deep}, #{skip}) - looking for get_extends() from #{fqns}" }
@@ -784,7 +830,8 @@ def inner_get_methods rooted_tag, scope, visibility, deep, skip, no_core = false
           end
           rooted_sc_tag = qualify_superclass(rooted_tag)
           unless rooted_sc_tag.nil?
-            result.concat inner_get_methods_from_reference(rooted_sc_tag, namespace_pin, rooted_type, scope, visibility, true, skip, true)
+            result.concat inner_get_methods_from_reference(rooted_sc_tag, namespace_pin, rooted_type, scope,
+                                                           visibility, true, skip, true)
           end
           unless no_core || fqns.empty?
             type = get_namespace_type(fqns)
@@ -817,9 +864,7 @@ def inner_get_constants fqns, visibility, skip
         result.concat inner_get_constants(qualify(is, fqns), [:public], skip)
       end
       fqsc = qualify_superclass(fqns)
-      unless %w[Object BasicObject].include?(fqsc)
-        result.concat inner_get_constants(fqsc, [:public], skip)
-      end
+      result.concat inner_get_constants(fqsc, [:public], skip) unless %w[Object BasicObject].include?(fqsc)
       result
     end
 
@@ -864,16 +909,21 @@ def inner_qualify name, root, skip
         if root == ''
           return ''
         else
+          root = root[2..-1] if root&.start_with?('::')
           return inner_qualify(root, '', skip)
         end
       else
-        return name if root == '' && store.namespace_exists?(name)
         roots = root.to_s.split('::')
         while roots.length > 0
-          fqns = roots.join('::') + '::' + name
-          return fqns if store.namespace_exists?(fqns)
-          incs = store.get_includes(roots.join('::'))
+          potential_root = roots.join('::')
+          potential_root = potential_root[2..-1] if potential_root.start_with?('::')
+          potential_fqns = potential_root + '::' + name
+          potential_fqns = potential_fqns[2..-1] if potential_fqns.start_with?('::')
+          fqns = resolve_fqns(potential_fqns)
+          return fqns if fqns
+          incs = store.get_includes(potential_root)
           incs.each do |inc|
+            next if potential_root == root && inc == name
             foundinc = inner_qualify(name, inc, skip)
             possibles.push foundinc unless foundinc.nil?
           end
@@ -886,11 +936,51 @@ def inner_qualify name, root, skip
             possibles.push foundinc unless foundinc.nil?
           end
         end
-        return name if store.namespace_exists?(name)
+        resolved_fqns = resolve_fqns(name)
+        return resolved_fqns if resolved_fqns
+
         return possibles.last
       end
     end
 
+    # @param fqns [String]
+    # @return [String, nil]
+    def resolve_fqns fqns
+      return fqns if store.namespace_exists?(fqns)
+
+      constant_namespace = nil
+      constant = store.constant_pins.find do |c|
+        constant_fqns = if c.namespace.empty?
+                          c.name
+                        else
+                          c.namespace + '::' + c.name
+                        end
+        constant_namespace = c.namespace
+        constant_fqns == fqns
+      end
+      return nil unless constant
+
+      return constant.return_type.namespace if constant.return_type.defined?
+
+      target_ns = resolve_trivial_constant(constant.assignment)
+      return nil unless target_ns
+      qualify_namespace target_ns, constant_namespace
+    end
+
+    # @param node [AST::Node]
+    # @return [String, nil]
+    def resolve_trivial_constant node
+      return nil unless node.is_a?(::Parser::AST::Node)
+      return nil unless node.type == :const
+      return nil if node.children.empty?
+      prefix_node = node.children[0]
+      prefix = ''
+      prefix = resolve_trivial_constant(prefix_node) + '::' unless prefix_node.nil? || prefix_node.children.empty?
+      const_name = node.children[1].to_s
+      return nil if const_name.empty?
+      return prefix + const_name
+    end
+
     # Get the namespace's type (Class or Module).
     #
     # @param fqns [String] A fully qualified namespace
@@ -898,7 +988,7 @@ def inner_qualify name, root, skip
     def get_namespace_type fqns
       return nil if fqns.nil?
       # @type [Pin::Namespace, nil]
-      pin = store.get_path_pins(fqns).select{|p| p.is_a?(Pin::Namespace)}.first
+      pin = get_namespace_pin(fqns)
       return nil if pin.nil?
       pin.type
     end
@@ -928,7 +1018,10 @@ def resolve_method_alias pin
       @method_alias_stack.push pin.path
       origin = get_method_stack(pin.full_context.tag, pin.original, scope: pin.scope, preserve_generics: true).first
       @method_alias_stack.pop
-      return nil if origin.nil?
+      if origin.nil?
+        Solargraph.assert_or_log(:alias_target_missing) { "Rejecting alias - target is missing while looking for #{pin.full_context.tag} #{pin.original}() in #{pin.scope} scope = #{pin.inspect}" }
+        return nil
+      end
       args = {
         location: pin.location,
         type_location: origin.type_location,
@@ -962,13 +1055,11 @@ def resolve_method_alias pin
 
     include Logging
 
-    private
-
     # @param namespace_pin [Pin::Namespace]
     # @param rooted_type [ComplexType]
     # @param pins [Enumerable<Pin::Base>]
     # @return [Array<Pin::Base>]
-    def erase_generics(namespace_pin, rooted_type, pins)
+    def erase_generics namespace_pin, rooted_type, pins
       return pins unless should_erase_generics_when_done?(namespace_pin, rooted_type)
 
       logger.debug("Erasing generics on namespace_pin=#{namespace_pin} / rooted_type=#{rooted_type}")
@@ -979,18 +1070,18 @@ def erase_generics(namespace_pin, rooted_type, pins)
 
     # @param namespace_pin [Pin::Namespace]
     # @param rooted_type [ComplexType]
-    def should_erase_generics_when_done?(namespace_pin, rooted_type)
+    def should_erase_generics_when_done? namespace_pin, rooted_type
       has_generics?(namespace_pin) && !can_resolve_generics?(namespace_pin, rooted_type)
     end
 
     # @param namespace_pin [Pin::Namespace]
-    def has_generics?(namespace_pin)
+    def has_generics? namespace_pin
       namespace_pin && !namespace_pin.generics.empty?
     end
 
     # @param namespace_pin [Pin::Namespace]
     # @param rooted_type [ComplexType]
-    def can_resolve_generics?(namespace_pin, rooted_type)
+    def can_resolve_generics? namespace_pin, rooted_type
       has_generics?(namespace_pin) && !rooted_type.all_params.empty?
     end
   end
diff --git a/lib/solargraph/api_map/cache.rb b/lib/solargraph/api_map/cache.rb
index 329a1e5e1..0052d91ea 100644
--- a/lib/solargraph/api_map/cache.rb
+++ b/lib/solargraph/api_map/cache.rb
@@ -4,9 +4,9 @@ module Solargraph
   class ApiMap
     class Cache
       def initialize
-        # @type [Hash{Array => Array<Pin::Method>}]
+        # @type [Hash{String => Array<Pin::Method>}]
         @methods = {}
-        # @type [Hash{(String, Array<String>) => Array<Pin::Base>}]
+        # @type [Hash{String, Array<String> => Array<Pin::Base>}]
         @constants = {}
         # @type [Hash{String => String}]
         @qualified_namespaces = {}
@@ -101,6 +101,7 @@ def empty?
 
       private
 
+      # @return [Array<Object>]
       def all_caches
         [@methods, @constants, @qualified_namespaces, @receiver_definitions, @clips]
       end
diff --git a/lib/solargraph/api_map/index.rb b/lib/solargraph/api_map/index.rb
index ea358297e..7f0e37153 100644
--- a/lib/solargraph/api_map/index.rb
+++ b/lib/solargraph/api_map/index.rb
@@ -37,27 +37,28 @@ def path_pin_hash
       # @param klass [Class<generic<T>>]
       # @return [Set<generic<T>>]
       def pins_by_class klass
-        # @type [Set<Solargraph::Pin::Base>]
+        # @type [Set<generic<T>>]
         s = Set.new
+        # @sg-ignore Need to handle block parameter destructuring
         @pin_select_cache[klass] ||= pin_class_hash.each_with_object(s) { |(key, o), n| n.merge(o) if key <= klass }
       end
 
-      # @return [Hash{String => Array<Pin::Reference::Include>}]
+      # @return [Hash{String => Array<String>}]
       def include_references
         @include_references ||= Hash.new { |h, k| h[k] = [] }
       end
 
-      # @return [Hash{String => Array<Pin::Reference::Extend>}]
+      # @return [Hash{String => Array<String>}]
       def extend_references
         @extend_references ||= Hash.new { |h, k| h[k] = [] }
       end
 
-      # @return [Hash{String => Array<Pin::Reference::Prepend>}]
+      # @return [Hash{String => Array<String>}]
       def prepend_references
         @prepend_references ||= Hash.new { |h, k| h[k] = [] }
       end
 
-      # @return [Hash{String => Array<Pin::Reference::Superclass>}]
+      # @return [Hash{String => Array<String>}]
       def superclass_references
         @superclass_references ||= Hash.new { |h, k| h[k] = [] }
       end
@@ -73,7 +74,7 @@ def merge pins
       attr_writer :pins, :pin_select_cache, :namespace_hash, :pin_class_hash, :path_pin_hash, :include_references,
                   :extend_references, :prepend_references, :superclass_references
 
-      # @return [self]
+      # @return [Solargraph::ApiMap::Index]
       def deep_clone
         Index.allocate.tap do |copy|
           copy.pin_select_cache = {}
@@ -89,8 +90,10 @@ def deep_clone
       end
 
       # @param new_pins [Array<Pin::Base>]
+      #
       # @return [self]
       def catalog new_pins
+        # @type [Hash{Class<generic<T>> => Set<generic<T>>}]
         @pin_select_cache = {}
         pins.concat new_pins
         set = new_pins.to_set
@@ -110,7 +113,7 @@ def catalog new_pins
       end
 
       # @param klass [Class<Pin::Reference>]
-      # @param hash [Hash{String => Array<Pin::Reference>}]
+      # @param hash [Hash{String => Array<String>}]
       # @return [void]
       def map_references klass, hash
         pins_by_class(klass).each do |pin|
@@ -120,7 +123,7 @@ def map_references klass, hash
 
       # Add references to a map
       #
-      # @param hash [Hash{String => Array<Pin::Reference>}]
+      # @param hash [Hash{String => Array<String>}]
       # @param reference_pin [Pin::Reference]
       #
       # @return [void]
@@ -144,9 +147,7 @@ def map_overrides
           pins = path_pin_hash[ovr.name]
           logger.debug { "ApiMap::Index#map_overrides: pins for path=#{ovr.name}: #{pins}" }
           pins.each do |pin|
-            new_pin = if pin.path.end_with?('#initialize')
-                        path_pin_hash[pin.path.sub(/#initialize/, '.new')].first
-                      end
+            new_pin = (path_pin_hash[pin.path.sub(/#initialize/, '.new')].first if pin.path.end_with?('#initialize'))
             (ovr.tags.map(&:tag_name) + ovr.delete).uniq.each do |tag|
               pin.docstring.delete_tags tag
               new_pin.docstring.delete_tags tag if new_pin
@@ -154,10 +155,13 @@ def map_overrides
             ovr.tags.each do |tag|
               pin.docstring.add_tag(tag)
               redefine_return_type pin, tag
-              if new_pin
-                new_pin.docstring.add_tag(tag)
-                redefine_return_type new_pin, tag
-              end
+              pin.reset_generated!
+
+              next unless new_pin
+
+              new_pin.docstring.add_tag(tag)
+              redefine_return_type new_pin, tag
+              new_pin.reset_generated!
             end
           end
         end
@@ -174,7 +178,6 @@ def redefine_return_type pin, tag
         pin.signatures.each do |sig|
           sig.instance_variable_set(:@return_type, ComplexType.try_parse(tag.type))
         end
-        pin.reset_generated!
       end
     end
   end
diff --git a/lib/solargraph/api_map/source_to_yard.rb b/lib/solargraph/api_map/source_to_yard.rb
index b44ebbf1a..7774a0d0b 100644
--- a/lib/solargraph/api_map/source_to_yard.rb
+++ b/lib/solargraph/api_map/source_to_yard.rb
@@ -45,7 +45,8 @@ def rake_yard store
           code_object_map[pin.path].docstring = pin.docstring
           store.get_includes(pin.path).each do |ref|
             include_object = code_object_at(pin.path, YARD::CodeObjects::ClassObject)
-            include_object.instance_mixins.push code_object_map[ref] unless include_object.nil? or include_object.nil?
+            code_object = code_object_map[ref]
+            include_object.instance_mixins.push code_object_map[ref] if include_object && code_object
           end
           store.get_extends(pin.path).each do |ref|
             extend_object = code_object_at(pin.path, YARD::CodeObjects::ClassObject)
diff --git a/lib/solargraph/api_map/store.rb b/lib/solargraph/api_map/store.rb
index d41a2a0ae..a0735a273 100644
--- a/lib/solargraph/api_map/store.rb
+++ b/lib/solargraph/api_map/store.rb
@@ -17,7 +17,7 @@ def pins
         index.pins
       end
 
-      # @param pinsets [Array<Enumerable<Pin::Base>>]
+      # @param pinsets [Array<Array<Pin::Base>>]
       # @return [Boolean] True if the index was updated
       def update *pinsets
         return catalog(pinsets) if pinsets.length != @pinsets.length
@@ -50,7 +50,7 @@ def inspect
 
       # @param fqns [String]
       # @param visibility [Array<Symbol>]
-      # @return [Enumerable<Solargraph::Pin::Base>]
+      # @return [Enumerable<Solargraph::Pin::Namespace, Solargraph::Pin::Constant>]
       def get_constants fqns, visibility = [:public]
         namespace_children(fqns).select { |pin|
           !pin.name.empty? && (pin.is_a?(Pin::Namespace) || pin.is_a?(Pin::Constant)) && visibility.include?(pin.visibility)
@@ -73,13 +73,13 @@ def get_methods fqns, scope: :instance, visibility: [:public]
       def get_superclass fq_tag
         raise "Do not prefix fully qualified tags with '::' - #{fq_tag.inspect}" if fq_tag.start_with?('::')
         sub = ComplexType.parse(fq_tag)
+        return sub.simplify_literals.name if sub.literal?
+        return 'Boolean' if %w[TrueClass FalseClass].include?(fq_tag)
         fqns = sub.namespace
         return superclass_references[fq_tag].first if superclass_references.key?(fq_tag)
         return superclass_references[fqns].first if superclass_references.key?(fqns)
         return 'Object' if fqns != 'BasicObject' && namespace_exists?(fqns)
         return 'Object' if fqns == 'Boolean'
-        simplified_literal_name = ComplexType.parse("#{fqns}").simplify_literals.name
-        return simplified_literal_name if simplified_literal_name != fqns
         nil
       end
 
@@ -117,7 +117,7 @@ def get_instance_variables(fqns, scope = :instance)
       end
 
       # @param fqns [String]
-      # @return [Enumerable<Solargraph::Pin::Base>]
+      # @return [Enumerable<Solargraph::Pin::ClassVariable>]
       def get_class_variables(fqns)
         namespace_children(fqns).select { |pin| pin.is_a?(Pin::ClassVariable)}
       end
@@ -133,16 +133,16 @@ def namespace_exists?(fqns)
         fqns_pins(fqns).any?
       end
 
-      # @return [Set<String>]
-      def namespaces
-        index.namespaces
-      end
-
       # @return [Enumerable<Solargraph::Pin::Namespace>]
       def namespace_pins
         pins_by_class(Solargraph::Pin::Namespace)
       end
 
+      # @return [Enumerable<Solargraph::Pin::Constant>]
+      def constant_pins
+        pins_by_class(Solargraph::Pin::Constant)
+      end
+
       # @return [Enumerable<Solargraph::Pin::Method>]
       def method_pins
         pins_by_class(Solargraph::Pin::Method)
@@ -206,10 +206,12 @@ def index
         @indexes.last
       end
 
-      # @param pinsets [Array<Enumerable<Pin::Base>>]
-      # @return [Boolean]
+      # @param pinsets [Array<Array<Pin::Base>>]
+      #
+      # @return [void]
       def catalog pinsets
         @pinsets = pinsets
+        # @type [Array<Index>]
         @indexes = []
         pinsets.each do |pins|
           if @indexes.last && pins.empty?
diff --git a/lib/solargraph/bench.rb b/lib/solargraph/bench.rb
index 3cb19a64b..e6180c933 100644
--- a/lib/solargraph/bench.rb
+++ b/lib/solargraph/bench.rb
@@ -37,6 +37,7 @@ def source_map_hash
                                       .to_h
     end
 
+    # @return [Set<SourceMap>]
     def icebox
       @icebox ||= (source_maps - [live_map])
     end
diff --git a/lib/solargraph/complex_type.rb b/lib/solargraph/complex_type.rb
index ac9599329..4e7bc4395 100644
--- a/lib/solargraph/complex_type.rb
+++ b/lib/solargraph/complex_type.rb
@@ -9,6 +9,7 @@ class ComplexType
     #   include TypeMethods
     include Equality
 
+    autoload :Conformance, 'solargraph/complex_type/conformance'
     autoload :TypeMethods, 'solargraph/complex_type/type_methods'
     autoload :UniqueType,  'solargraph/complex_type/unique_type'
 
@@ -17,15 +18,17 @@ def initialize types = [UniqueType::UNDEFINED]
       # @todo @items here should not need an annotation
       # @type [Array<UniqueType>]
       items = types.flat_map(&:items).uniq(&:to_s)
+
+      # Canonicalize 'true, false' to the non-runtime-type 'Boolean'
       if items.any? { |i| i.name == 'false' } && items.any? { |i| i.name == 'true' }
         items.delete_if { |i| i.name == 'false' || i.name == 'true' }
-        items.unshift(ComplexType::BOOLEAN)
+        items.unshift(UniqueType::BOOLEAN)
       end
+
       items = [UniqueType::UNDEFINED] if items.any?(&:undefined?)
       @items = items
     end
 
-    # @sg-ignore Fix "Not enough arguments to Module#protected"
     protected def equality_fields
       [self.class, items]
     end
@@ -76,9 +79,13 @@ def self_to_type dst
     end
 
     # @yieldparam [UniqueType]
+    # @yieldreturn [UniqueType]
     # @return [Array<UniqueType>]
-    def map &block
-      @items.map &block
+    # @sg-ignore Declared return type
+    #   ::Array<::Solargraph::ComplexType::UniqueType> does not match
+    #   inferred type ::Array<::Proc> for Solargraph::ComplexType#map
+    def map(&block)
+      @items.map(&block)
     end
 
     # @yieldparam [UniqueType]
@@ -99,12 +106,6 @@ def each_unique_type &block
       end
     end
 
-    # @param atype [ComplexType] type which may be assigned to this type
-    # @param api_map [ApiMap] The ApiMap that performs qualification
-    def can_assign?(api_map, atype)
-      any? { |ut| ut.can_assign?(api_map, atype) }
-    end
-
     # @return [Integer]
     def length
       @items.length
@@ -155,10 +156,12 @@ def to_s
       map(&:tag).join(', ')
     end
 
+    # @return [String]
     def tags
       map(&:tag).join(', ')
     end
 
+    # @return [String]
     def simple_tags
       simplify_literals.tags
     end
@@ -172,10 +175,65 @@ def downcast_to_literal_if_possible
       ComplexType.new(items.map(&:downcast_to_literal_if_possible))
     end
 
+    # @return [String]
     def desc
       rooted_tags
     end
 
+    # @param api_map [ApiMap]
+    # @param expected [ComplexType, ComplexType::UniqueType]
+    # @param situation [:method_call, :return_type, :assignment]
+    # @param allow_subtype_skew [Boolean] if false, check if any
+    #   subtypes of the expected type match the inferred type
+    # @param allow_reverse_match [Boolean] if true, check if any subtypes
+    #   of the expected type match the inferred type
+    # @param allow_empty_params [Boolean] if true, allow a general
+    #   inferred type without parameters to conform to a more specific
+    #   expected type
+    # @param allow_any_match [Boolean] if true, any unique type
+    #   matched in the inferred qualifies as a match
+    # @param allow_undefined [Boolean] if true, treat undefined as a
+    #   wildcard that matches anything
+    # @param rules [Array<:allow_subtype_skew, :allow_empty_params, :allow_reverse_match, :allow_any_match, :allow_undefined, :allow_unresolved_generic, :allow_unmatched_interface>]
+    # @param variance [:invariant, :covariant, :contravariant]
+    # @return [Boolean]
+    def conforms_to?(api_map, expected,
+                     situation,
+                     rules = [],
+                     variance: erased_variance(situation))
+      expected = expected.downcast_to_literal_if_possible
+      inferred = downcast_to_literal_if_possible
+
+      return duck_types_match?(api_map, expected, inferred) if expected.duck_type?
+
+      if rules.include? :allow_any_match
+        inferred.any? do |inf|
+          inf.conforms_to?(api_map, expected, situation, rules,
+                           variance: variance)
+        end
+      else
+        inferred.all? do |inf|
+          inf.conforms_to?(api_map, expected, situation, rules,
+                           variance: variance)
+        end
+      end
+    end
+
+    # @param api_map [ApiMap]
+    # @param expected [ComplexType]
+    # @param inferred [ComplexType]
+    # @return [Boolean]
+    def duck_types_match? api_map, expected, inferred
+      raise ArgumentError, 'Expected type must be duck type' unless expected.duck_type?
+      expected.each do |exp|
+        next unless exp.duck_type?
+        quack = exp.to_s[1..]
+        return false if api_map.get_method_stack(inferred.namespace, quack, scope: inferred.scope).empty?
+      end
+      true
+    end
+
+    # @return [String]
     def rooted_tags
       map(&:rooted_tag).join(', ')
     end
@@ -200,6 +258,7 @@ def generic?
       any?(&:generic?)
     end
 
+    # @return [ComplexType]
     def simplify_literals
       ComplexType.new(map(&:simplify_literals))
     end
@@ -253,6 +312,13 @@ def all_rooted?
       all?(&:all_rooted?)
     end
 
+    # @param other [ComplexType, UniqueType]
+    def erased_version_of?(other)
+      return false if items.length != 1 || other.items.length != 1
+
+      @items.first.erased_version_of?(other.items.first)
+    end
+
     # every top-level type has resolved to be fully qualified; see
     # #all_rooted? to check their subtypes as well
     def rooted?
diff --git a/lib/solargraph/complex_type/conformance.rb b/lib/solargraph/complex_type/conformance.rb
new file mode 100644
index 000000000..fdb962916
--- /dev/null
+++ b/lib/solargraph/complex_type/conformance.rb
@@ -0,0 +1,182 @@
+# frozen_string_literal: true
+
+module Solargraph
+  class ComplexType
+    # Checks whether a type can be used in a given situation
+    class Conformance
+      # @param api_map [ApiMap]
+      # @param inferred [ComplexType::UniqueType]
+      # @param expected [ComplexType::UniqueType]
+      # @param situation [:method_call, :return_type]
+      # @param rules [Array<:allow_subtype_skew, :allow_empty_params, :allow_reverse_match,
+      #   :allow_any_match, :allow_undefined, :allow_unresolved_generic,
+      #   :allow_unmatched_interface>]
+      # @param variance [:invariant, :covariant, :contravariant]
+      def initialize api_map, inferred, expected,
+                     situation = :method_call, rules = [],
+                     variance: inferred.erased_variance(situation)
+        @api_map = api_map
+        @inferred = inferred
+        @expected = expected
+        @situation = situation
+        @rules = rules
+        @variance = variance
+        # :nocov:
+        unless expected.is_a?(UniqueType)
+          raise "Expected type must be a UniqueType, got #{expected.class} in #{expected.inspect}"
+        end
+        # :nocov:
+        return if inferred.is_a?(UniqueType)
+        # :nocov:
+        raise "Inferred type must be a UniqueType, got #{inferred.class} in #{inferred.inspect}"
+        # :nocov:
+      end
+
+      def conforms_to_unique_type?
+        unless expected.is_a?(UniqueType)
+          # :nocov:
+          raise "Expected type must be a UniqueType, got #{expected.class} in #{expected}"
+          # :nocov:
+        end
+
+        downcast_inferred = inferred.downcast_to_literal_if_possible
+        # First see if we need to turn e.g. NilClass into nil to match expectations
+        if expected.literal? && (downcast_inferred.name != inferred.name)
+          return with_new_types(downcast_inferred, expected).conforms_to_unique_type?
+        elsif use_simplified_inferred_type?
+          # ...if not, see if we need to do the reverse, or turn a
+          # more specific literal type (1, 2, 3) into a more general
+          # one (Integer)
+          return with_new_types(inferred.simplify_literals, expected).conforms_to_unique_type?
+        end
+        return true if ignore_interface?
+        return true if conforms_via_reverse_match?
+
+        if rules.include?(:allow_subtype_skew) && !expected.all_params.empty?
+          # parameters are not considered in this case
+          return with_new_types(inferred, expected.erase_parameters).conforms_to_unique_type?
+        end
+
+        return with_new_types(inferred.erase_parameters, expected).conforms_to_unique_type? if only_inferred_parameters?
+
+        return conforms_via_stripped_expected_parameters? if can_strip_expected_parameters?
+
+        return true if inferred == expected
+
+        return false unless erased_type_conforms?
+
+        return true if inferred.all_params.empty? && rules.include?(:allow_empty_params)
+
+        # at this point we know the erased type is fine - time to look at parameters
+
+        # there's an implicit 'any' on the expectation parameters
+        # if there are none specified
+        return true if expected.all_params.empty?
+
+        return false unless key_types_conform?
+
+        subtypes_conform?
+      end
+
+      private
+
+      def use_simplified_inferred_type?
+        inferred.literal? && !expected.literal?
+      end
+
+      def only_inferred_parameters?
+        !expected.parameters? && inferred.parameters?
+      end
+
+      def conforms_via_stripped_expected_parameters?
+        with_new_types(inferred, expected.erase_parameters).conforms_to_unique_type?
+      end
+
+      def ignore_interface?
+        (expected.any?(&:interface?) && rules.include?(:allow_unmatched_interface)) ||
+          (inferred.interface? && rules.include?(:allow_unmatched_interface))
+      end
+
+      def can_strip_expected_parameters?
+        expected.parameters? && !inferred.parameters? && rules.include?(:allow_empty_params)
+      end
+
+      def conforms_via_reverse_match?
+        return false unless rules.include? :allow_reverse_match
+
+        expected.conforms_to?(api_map, inferred, situation,
+                              rules - [:allow_reverse_match],
+                              variance: variance)
+      end
+
+      def erased_type_conforms?
+        case variance
+        when :invariant
+          return false unless inferred.name == expected.name
+        when :covariant
+          # covariant: we can pass in a more specific type
+          # we contain the expected mix-in, or we have a more specific type
+          return false unless api_map.type_include?(inferred.name, expected.name) ||
+                              api_map.super_and_sub?(expected.name, inferred.name) ||
+                              inferred.name == expected.name
+        when :contravariant
+          # contravariant: we can pass in a more general type
+          # we contain the expected mix-in, or we have a more general type
+          return false unless api_map.type_include?(inferred.name, expected.name) ||
+                              api_map.super_and_sub?(inferred.name, expected.name) ||
+                              inferred.name == expected.name
+        else
+          # :nocov:
+          raise "Unknown variance: #{variance.inspect}"
+          # :nocov:
+        end
+        true
+      end
+
+      def key_types_conform?
+        return true if expected.key_types.empty?
+
+        return false if inferred.key_types.empty?
+
+        unless ComplexType.new(inferred.key_types).conforms_to?(api_map,
+                                                                ComplexType.new(expected.key_types),
+                                                                situation,
+                                                                rules,
+                                                                variance: inferred.parameter_variance(situation))
+          return false
+        end
+
+        true
+      end
+
+      def subtypes_conform?
+        return true if expected.subtypes.empty?
+
+        return true if expected.subtypes.any?(&:undefined?) && rules.include?(:allow_undefined)
+
+        return true if inferred.subtypes.any?(&:undefined?) && rules.include?(:allow_undefined)
+
+        return true if inferred.subtypes.all?(&:generic?) && rules.include?(:allow_unresolved_generic)
+
+        return true if expected.subtypes.all?(&:generic?) && rules.include?(:allow_unresolved_generic)
+
+        return false if inferred.subtypes.empty?
+
+        ComplexType.new(inferred.subtypes).conforms_to?(api_map,
+                                                        ComplexType.new(expected.subtypes),
+                                                        situation,
+                                                        rules,
+                                                        variance: inferred.parameter_variance(situation))
+      end
+
+      # @return [self]
+      # @param inferred [ComplexType::UniqueType]
+      # @param expected [ComplexType::UniqueType]
+      def with_new_types inferred, expected
+        self.class.new(api_map, inferred, expected, situation, rules, variance: variance)
+      end
+
+      attr_reader :api_map, :inferred, :expected, :situation, :rules, :variance
+    end
+  end
+end
diff --git a/lib/solargraph/complex_type/type_methods.rb b/lib/solargraph/complex_type/type_methods.rb
index e6d596244..8b5cfea6b 100644
--- a/lib/solargraph/complex_type/type_methods.rb
+++ b/lib/solargraph/complex_type/type_methods.rb
@@ -10,11 +10,7 @@ class ComplexType
     #     @name: String
     #     @subtypes: Array<ComplexType>
     #     @rooted: boolish
-    #   methods:
-    #     transform()
-    #     all_params()
-    #     rooted?()
-    #     can_root_name?()
+    #   methods: (see @!method declarations below)
     module TypeMethods
       # @!method transform(new_name = nil, &transform_type)
       #   @param new_name [String, nil]
@@ -24,6 +20,9 @@ module TypeMethods
       # @!method all_params
       #   @return [Array<ComplexType>]
       # @!method rooted?
+      # @!method literal?
+      # @!method simplify_literals
+      #   @return [ComplexType::UniqueType, ComplexType]
       # @!method can_root_name?(name_to_check = nil)
       #   @param name_to_check [String, nil]
 
@@ -69,6 +68,18 @@ def undefined?
         name == 'undefined'
       end
 
+      # Variance of the type ignoring any type parameters
+      # @return [Symbol]
+      # @param situation [Symbol] The situation in which the variance is being considered.
+      def erased_variance situation = :method_call
+        # :nocov:
+        unless %i[method_call return_type assignment].include?(situation)
+          raise "Unknown situation: #{situation.inspect}"
+        end
+        # :nocov:
+        :covariant
+      end
+
       # @param generics_to_erase [Enumerable<String>]
       # @return [self]
       def erase_generics(generics_to_erase)
@@ -124,12 +135,14 @@ def key_types
       def namespace
         # if priority higher than ||=, old implements cause unnecessary check
         @namespace ||= lambda do
-          return 'Object' if duck_type?
+          return simplify_literals.namespace if literal?
+          return 'Object' if duck_type? || name == 'Boolean'
           return 'NilClass' if nil_type?
           return (name == 'Class' || name == 'Module') && !subtypes.empty? ? subtypes.first.name : name
         end.call
       end
 
+      # @return [ComplexType, UniqueType]
       def namespace_type
         return ComplexType.parse('::Object') if duck_type?
         return ComplexType.parse('::NilClass') if nil_type?
diff --git a/lib/solargraph/complex_type/unique_type.rb b/lib/solargraph/complex_type/unique_type.rb
index 63a6ae15b..a074a3547 100644
--- a/lib/solargraph/complex_type/unique_type.rb
+++ b/lib/solargraph/complex_type/unique_type.rb
@@ -11,7 +11,6 @@ class UniqueType
 
       attr_reader :all_params, :subtypes, :key_types
 
-      # @sg-ignore Fix "Not enough arguments to Module#protected"
       protected def equality_fields
         [@name, @all_params, @subtypes, @key_types]
       end
@@ -74,6 +73,8 @@ def initialize(name, key_types = [], subtypes = [], rooted:, parameters_type: ni
         if parameters_type.nil?
           raise "You must supply parameters_type if you provide parameters" unless key_types.empty? && subtypes.empty?
         end
+
+        raise "name must be a String" unless name.is_a?(String)
         raise "Please remove leading :: and set rooted instead - #{name.inspect}" if name.start_with?('::')
         @name = name
         @parameters_type = parameters_type
@@ -101,6 +102,7 @@ def to_s
         tag
       end
 
+      # @return [self]
       def simplify_literals
         transform do |t|
           next t unless t.literal?
@@ -112,10 +114,12 @@ def literal?
         non_literal_name != name
       end
 
+      # @return [String]
       def non_literal_name
         @non_literal_name ||= determine_non_literal_name
       end
 
+      # @return [String]
       def determine_non_literal_name
         # https://github.com/ruby/rbs/blob/master/docs/syntax.md
         #
@@ -126,7 +130,8 @@ def determine_non_literal_name
         #    | `false`
         return name if name.empty?
         return 'NilClass' if name == 'nil'
-        return 'Boolean' if ['true', 'false'].include?(name)
+        return 'TrueClass' if name == 'true'
+        return 'FalseClass' if name == 'false'
         return 'Symbol' if name[0] == ':'
         return 'String' if ['"', "'"].include?(name[0])
         return 'Integer' if name.match?(/^-?\d+$/)
@@ -147,10 +152,86 @@ def ==(other)
         eql?(other)
       end
 
+      # https://www.playfulpython.com/type-hinting-covariance-contra-variance/
+
+      # "[Expected] type variables that are COVARIANT can be substituted with
+      #  a more specific [inferred] type without causing errors"
+      #
+      # "[Expected] type variables that are CONTRAVARIANT can be substituted
+      #   with a more general [inferred] type without causing errors"
+      #
+      # "[Expected] types where neither is possible are INVARIANT"
+      #
+      # @param _situation [:method_call]
+      # @param default [Symbol] The default variance to return if the type is not one of the special cases
+      #
+      # @return [:invariant, :covariant, :contravariant]
+      def parameter_variance _situation, default = :covariant
+        # @todo RBS can specify variance - maybe we can use that info
+        #   and also let folks specify?
+        #
+        # Array/Set: ideally invariant, since we don't know if user is
+        #   going to add new stuff into it or read it.  But we don't
+        #   have a way to specify, so we use covariant
+        # Enumerable: covariant:  can't be changed, so we can pass
+        #   in more specific subtypes
+        # Hash: read-only would be covariant, read-write would be
+        #   invariant if we could distinguish that - should default to
+        #   covariant
+        # contravariant?: Proc - can be changed, so we can pass
+        #   in less specific super types
+        if ['Hash', 'Tuple', 'Array', 'Set', 'Enumerable'].include?(name) && fixed_parameters?
+          :covariant
+        else
+          default
+        end
+      end
+
+      # Whether this is an RBS interface like _ToAry or _Each.
+      def interface?
+        name.start_with?('_')
+      end
+
+      # @param other [UniqueType]
+      def erased_version_of?(other)
+        name == other.name && (all_params.empty? || all_params.all?(&:undefined?))
+      end
+
+      # @param api_map [ApiMap]
+      # @param expected [ComplexType::UniqueType, ComplexType]
+      # @param situation [:method_call, :assignment, :return]
+      # @param rules [Array<:allow_subtype_skew, :allow_empty_params, :allow_reverse_match, :allow_any_match, :allow_undefined, :allow_unresolved_generic>]
+      # @param variance [:invariant, :covariant, :contravariant]
+      def conforms_to?(api_map, expected, situation, rules = [],
+                       variance: erased_variance(situation))
+        return true if undefined? && rules.include?(:allow_undefined)
+
+        # @todo teach this to validate duck types as inferred type
+        return true if duck_type?
+
+        # complex types as expectations are unions - we only need to
+        # match one of their unique types
+        expected.any? do |expected_unique_type|
+          # :nocov:
+          unless expected_unique_type.instance_of?(UniqueType)
+            raise "Expected type must be a UniqueType, got #{expected_unique_type.class} in #{expected.inspect}"
+          end
+          # :nocov:
+          conformance = Conformance.new(api_map, self, expected_unique_type, situation,
+                                        rules, variance: variance)
+          conformance.conforms_to_unique_type?
+        end
+      end
+
       def hash
         [self.class, @name, @key_types, @sub_types, @rooted, @all_params, @parameters_type].hash
       end
 
+      # @return [self]
+      def erase_parameters
+        UniqueType.new(name, rooted: rooted?, parameters_type: parameters_type)
+      end
+
       # @return [Array<UniqueType>]
       def items
         [self]
@@ -167,6 +248,7 @@ def rbs_name
         end
       end
 
+      # @return [String]
       def desc
         rooted_tags
       end
@@ -180,7 +262,7 @@ def to_rbs
         elsif name.downcase == 'nil'
           'nil'
         elsif name == GENERIC_TAG_NAME
-          all_params.first.name
+          all_params.first&.name
         elsif ['Class', 'Module'].include?(name)
           rbs_name
         elsif ['Tuple', 'Array'].include?(name) && fixed_parameters?
@@ -232,18 +314,6 @@ def generic?
         name == GENERIC_TAG_NAME || all_params.any?(&:generic?)
       end
 
-      # @param api_map [ApiMap] The ApiMap that performs qualification
-      # @param atype [ComplexType] type which may be assigned to this type
-      def can_assign?(api_map, atype)
-        logger.debug { "UniqueType#can_assign?(self=#{rooted_tags.inspect}, atype=#{atype.rooted_tags.inspect})" }
-        downcasted_atype = atype.downcast_to_literal_if_possible
-        out = downcasted_atype.all? do |autype|
-          autype.name == name || api_map.super_and_sub?(name, autype.name)
-        end
-        logger.debug { "UniqueType#can_assign?(self=#{rooted_tags.inspect}, atype=#{atype.rooted_tags.inspect}) => #{out}" }
-        out
-      end
-
       # @return [UniqueType]
       def downcast_to_literal_if_possible
         SINGLE_SUBTYPE.fetch(rooted_tag, self)
@@ -251,7 +321,7 @@ def downcast_to_literal_if_possible
 
       # @param generics_to_resolve [Enumerable<String>]
       # @param context_type [UniqueType, nil]
-      # @param resolved_generic_values [Hash{String => ComplexType}] Added to as types are encountered or resolved
+      # @param resolved_generic_values [Hash{String => ComplexType, UniqueType}] Added to as types are encountered or resolved
       # @return [UniqueType, ComplexType]
       def resolve_generics_from_context generics_to_resolve, context_type, resolved_generic_values: {}
         if name == ComplexType::GENERIC_TAG_NAME
@@ -349,9 +419,9 @@ def to_a
 
       # @param new_name [String, nil]
       # @param make_rooted [Boolean, nil]
-      # @param new_key_types [Array<UniqueType>, nil]
+      # @param new_key_types [Array<ComplexType>, nil]
       # @param rooted [Boolean, nil]
-      # @param new_subtypes [Array<UniqueType>, nil]
+      # @param new_subtypes [Array<ComplexType>, nil]
       # @return [self]
       def recreate(new_name: nil, make_rooted: nil, new_key_types: nil, new_subtypes: nil)
         raise "Please remove leading :: and set rooted instead - #{new_name}" if new_name&.start_with?('::')
@@ -433,6 +503,11 @@ def self_to_type dst
         end
       end
 
+      # @yieldreturn [Boolean]
+      def any? &block
+        block.yield self
+      end
+
       def all_rooted?
         return true if name == GENERIC_TAG_NAME
         rooted? && all_params.all?(&:rooted?)
diff --git a/lib/solargraph/convention/data_definition/data_assignment_node.rb b/lib/solargraph/convention/data_definition/data_assignment_node.rb
index 7aadcf190..0ecfb88eb 100644
--- a/lib/solargraph/convention/data_definition/data_assignment_node.rb
+++ b/lib/solargraph/convention/data_definition/data_assignment_node.rb
@@ -22,6 +22,7 @@ class << self
           #     s(:def, :foo,
           #       s(:args),
           #       s(:send, nil, :bar))))
+          # @param node [Parser::AST::Node]
           def match?(node)
             return false unless node&.type == :casgn
             return false if node.children[2].nil?
diff --git a/lib/solargraph/convention/data_definition/data_definition_node.rb b/lib/solargraph/convention/data_definition/data_definition_node.rb
index dd5929822..5ee79b73d 100644
--- a/lib/solargraph/convention/data_definition/data_definition_node.rb
+++ b/lib/solargraph/convention/data_definition/data_definition_node.rb
@@ -25,6 +25,7 @@ class << self
           #     s(:def, :foo,
           #       s(:args),
           #       s(:send, nil, :bar)))
+          # @param node [Parser::AST::Node]
           def match?(node)
             return false unless node&.type == :class
 
@@ -46,7 +47,7 @@ def data_definition_node?(data_node)
           end
         end
 
-        # @return [Parser::AST::Node]
+        # @param node [Parser::AST::Node]
         def initialize(node)
           @node = node
         end
diff --git a/lib/solargraph/convention/struct_definition.rb b/lib/solargraph/convention/struct_definition.rb
index 058e2de30..b34ae5494 100644
--- a/lib/solargraph/convention/struct_definition.rb
+++ b/lib/solargraph/convention/struct_definition.rb
@@ -102,7 +102,7 @@ def process
 
           private
 
-          # @return [StructDefintionNode, nil]
+          # @return [StructDefintionNode, StructAssignmentNode, nil]
           def struct_definition_node
             @struct_definition_node ||= if StructDefintionNode.match?(node)
                                           StructDefintionNode.new(node)
diff --git a/lib/solargraph/convention/struct_definition/struct_assignment_node.rb b/lib/solargraph/convention/struct_definition/struct_assignment_node.rb
index 04f96d40e..2816de6ed 100644
--- a/lib/solargraph/convention/struct_definition/struct_assignment_node.rb
+++ b/lib/solargraph/convention/struct_definition/struct_assignment_node.rb
@@ -22,6 +22,8 @@ class << self
           #     s(:def, :foo,
           #       s(:args),
           #       s(:send, nil, :bar))))
+          #
+          # @param node [Parser::AST::Node]
           def match?(node)
             return false unless node&.type == :casgn
             return false if node.children[2].nil?
diff --git a/lib/solargraph/convention/struct_definition/struct_definition_node.rb b/lib/solargraph/convention/struct_definition/struct_definition_node.rb
index 540320c37..7c3d722d0 100644
--- a/lib/solargraph/convention/struct_definition/struct_definition_node.rb
+++ b/lib/solargraph/convention/struct_definition/struct_definition_node.rb
@@ -25,6 +25,7 @@ class << self
           #     s(:def, :foo,
           #       s(:args),
           #       s(:send, nil, :bar)))
+          # @param node [Parser::AST::Node]
           def match?(node)
             return false unless node&.type == :class
 
@@ -46,7 +47,7 @@ def struct_definition_node?(struct_node)
           end
         end
 
-        # @return [Parser::AST::Node]
+        # @param node [Parser::AST::Node]
         def initialize(node)
           @node = node
         end
diff --git a/lib/solargraph/diagnostics/rubocop_helpers.rb b/lib/solargraph/diagnostics/rubocop_helpers.rb
index 4eb2c711d..f6f4c82c8 100644
--- a/lib/solargraph/diagnostics/rubocop_helpers.rb
+++ b/lib/solargraph/diagnostics/rubocop_helpers.rb
@@ -19,8 +19,6 @@ def require_rubocop(version = nil)
           gem_path = Gem::Specification.find_by_name('rubocop', version).full_gem_path
           gem_lib_path = File.join(gem_path, 'lib')
           $LOAD_PATH.unshift(gem_lib_path) unless $LOAD_PATH.include?(gem_lib_path)
-        # @todo Gem::MissingSpecVersionError is undocumented for some reason
-        # @sg-ignore
         rescue Gem::MissingSpecVersionError => e
           raise InvalidRubocopVersionError,
                 "could not find '#{e.name}' (#{e.requirement}) - "\
diff --git a/lib/solargraph/doc_map.rb b/lib/solargraph/doc_map.rb
index 43c8768b0..b94bc558e 100644
--- a/lib/solargraph/doc_map.rb
+++ b/lib/solargraph/doc_map.rb
@@ -5,122 +5,81 @@
 require 'open3'
 
 module Solargraph
-  # A collection of pins generated from required gems.
+  # A collection of pins generated from specific 'require' statements
+  # in code.  Multiple can be created per workspace, to represent the
+  # pins available in different files based on their particular
+  # 'require' lines.
   #
   class DocMap
     include Logging
 
-    # @return [Array<String>]
-    attr_reader :requires
-    alias required requires
+    # @return [Workspace]
+    attr_reader :workspace
 
-    # @return [Array<Gem::Specification>]
-    attr_reader :preferences
+    # @param requires [Array<String>]
+    # @param workspace [Workspace]
+    # @param out [IO, nil] output stream for logging
+    def initialize requires, workspace, out: $stderr
+      @provided_requires = requires.compact
+      @workspace = workspace
+      @out = out
+    end
 
-    # @return [Array<Pin::Base>]
-    attr_reader :pins
+    # @return [Array<String>]
+    def requires
+      @requires ||= @provided_requires + (workspace.global_environ&.requires || [])
+    end
+    alias required requires
 
     # @return [Array<Gem::Specification>]
     def uncached_gemspecs
-      uncached_yard_gemspecs.concat(uncached_rbs_collection_gemspecs)
-                            .sort
-                            .uniq { |gemspec| "#{gemspec.name}:#{gemspec.version}" }
+      if @uncached_gemspecs.nil?
+        @uncached_gemspecs = []
+        pins # force lazy-loaded pin lookup
+      end
+      @uncached_gemspecs
     end
 
-    # @return [Array<Gem::Specification>]
-    attr_reader :uncached_yard_gemspecs
-
-    # @return [Array<Gem::Specification>]
-    attr_reader :uncached_rbs_collection_gemspecs
-
-    # @return [String, nil]
-    attr_reader :rbs_collection_path
-
-    # @return [String, nil]
-    attr_reader :rbs_collection_config_path
-
-    # @return [Workspace, nil]
-    attr_reader :workspace
-
-    # @return [Environ]
-    attr_reader :environ
-
-    # @param requires [Array<String>]
-    # @param preferences [Array<Gem::Specification>]
-    # @param workspace [Workspace, nil]
-    def initialize(requires, preferences, workspace = nil)
-      @requires = requires.compact
-      @preferences = preferences.compact
-      @workspace = workspace
-      @rbs_collection_path = workspace&.rbs_collection_path
-      @rbs_collection_config_path = workspace&.rbs_collection_config_path
-      @environ = Convention.for_global(self)
-      @requires.concat @environ.requires if @environ
-      load_serialized_gem_pins
-      pins.concat @environ.pins
+    # @return [Array<Pin::Base>]
+    def pins
+      @pins ||= load_serialized_gem_pins + (workspace.global_environ&.pins || [])
     end
 
-    # @param out [IO]
     # @return [void]
-    def cache_all!(out)
-      # if we log at debug level:
-      if logger.info?
-        gem_desc = uncached_gemspecs.map { |gemspec| "#{gemspec.name}:#{gemspec.version}" }.join(', ')
-        logger.info "Caching pins for gems: #{gem_desc}" unless uncached_gemspecs.empty?
-      end
-      logger.debug { "Caching for YARD: #{uncached_yard_gemspecs.map(&:name)}" }
-      logger.debug { "Caching for RBS collection: #{uncached_rbs_collection_gemspecs.map(&:name)}" }
-      load_serialized_gem_pins
-      uncached_gemspecs.each do |gemspec|
-        cache(gemspec, out: out)
-      end
-      load_serialized_gem_pins
-      @uncached_rbs_collection_gemspecs = []
-      @uncached_yard_gemspecs = []
+    def reset_pins!
+      @uncached_gemspecs = nil
+      @pins = nil
     end
 
-    # @param gemspec [Gem::Specification]
-    # @param out [IO]
-    # @return [void]
-    def cache_yard_pins(gemspec, out)
-      pins = GemPins.build_yard_pins(yard_plugins, gemspec)
-      PinCache.serialize_yard_gem(gemspec, pins)
-      logger.info { "Cached #{pins.length} YARD pins for gem #{gemspec.name}:#{gemspec.version}" } unless pins.empty?
+    # @return [Solargraph::PinCache]
+    def pin_cache
+      @pin_cache ||= workspace.fresh_pincache
     end
 
-    # @param gemspec [Gem::Specification]
-    # @param out [IO]
-    # @return [void]
-    def cache_rbs_collection_pins(gemspec, out)
-      rbs_map = RbsMap.from_gemspec(gemspec, rbs_collection_path, rbs_collection_config_path)
-      pins = rbs_map.pins
-      rbs_version_cache_key = rbs_map.cache_key
-      # cache pins even if result is zero, so we don't retry building pins
-      pins ||= []
-      PinCache.serialize_rbs_collection_gem(gemspec, rbs_version_cache_key, pins)
-      logger.info { "Cached #{pins.length} RBS collection pins for gem #{gemspec.name} #{gemspec.version} with cache_key #{rbs_version_cache_key.inspect}" unless pins.empty? }
+    def any_uncached?
+      uncached_gemspecs.any?
     end
 
-    # @param gemspec [Gem::Specification]
-    # @param rebuild [Boolean] whether to rebuild the pins even if they are cached
+    # Cache all pins needed for the sources in this doc_map
     # @param out [IO, nil] output stream for logging
     # @return [void]
-    def cache(gemspec, rebuild: false, out: nil)
-      build_yard = uncached_yard_gemspecs.include?(gemspec) || rebuild
-      build_rbs_collection = uncached_rbs_collection_gemspecs.include?(gemspec) || rebuild
-      if build_yard || build_rbs_collection
-        type = []
-        type << 'YARD' if build_yard
-        type << 'RBS collection' if build_rbs_collection
-        out.puts("Caching #{type.join(' and ')} pins for gem #{gemspec.name}:#{gemspec.version}") if out
+    def cache_doc_map_gems! out
+      unless uncached_gemspecs.empty?
+        logger.info do
+          gem_desc = uncached_gemspecs.map { |gemspec| "#{gemspec.name}:#{gemspec.version}" }.join(', ')
+          "Caching pins for gems: #{gem_desc}"
+        end
       end
-      cache_yard_pins(gemspec, out) if build_yard
-      cache_rbs_collection_pins(gemspec, out) if build_rbs_collection
-    end
-
-    # @return [Array<Gem::Specification>]
-    def gemspecs
-      @gemspecs ||= required_gems_map.values.compact.flatten
+      time = Benchmark.measure do
+        uncached_gemspecs.each do |gemspec|
+          cache(gemspec, out: out)
+        end
+      end
+      milliseconds = (time.real * 1000).round
+      if (milliseconds > 500) && uncached_gemspecs.any? && out && uncached_gemspecs.any?
+        out.puts "Built #{uncached_gemspecs.length} gems in #{milliseconds} ms"
+      end
+      reset_pins!
     end
 
     # @return [Array<String>]
@@ -128,305 +87,90 @@ def unresolved_requires
       @unresolved_requires ||= required_gems_map.select { |_, gemspecs| gemspecs.nil? }.keys
     end
 
-    # @return [Hash{Array(String, String) => Array<Gem::Specification>}] Indexed by gemspec name and version
-    def self.all_yard_gems_in_memory
-      @yard_gems_in_memory ||= {}
-    end
-
-    # @return [Hash{String => Array<Pin::Base>}] stored by RBS collection path
-    def self.all_rbs_collection_gems_in_memory
-      @rbs_collection_gems_in_memory ||= {}
-    end
-
-    # @return [Hash{Array(String, String) => Array<Pin::Base>}] Indexed by gemspec name and version
-    def yard_pins_in_memory
-      self.class.all_yard_gems_in_memory
-    end
-
-    # @return [Hash{Array(String, String) => Array<Pin::Base>}] Indexed by gemspec name and version
-    def rbs_collection_pins_in_memory
-      self.class.all_rbs_collection_gems_in_memory[rbs_collection_path] ||= {}
-    end
-
-    # @return [Hash{Array(String, String) => Array<Pin::Base>}] Indexed by gemspec name and version
-    def self.all_combined_pins_in_memory
-      @combined_pins_in_memory ||= {}
+    # @param out [IO, nil] output stream for logging
+    # @return [Set<Gem::Specification>]
+    # @param out [IO]
+    def dependencies out: $stderr
+      @dependencies ||=
+        begin
+          all_deps = gemspecs.flat_map { |spec| workspace.fetch_dependencies(spec, out: out) }
+          existing_gems = gemspecs.map(&:name)
+          all_deps.reject { |gemspec| existing_gems.include? gemspec.name }.to_set
+        end
     end
 
-    # @todo this should also include an index by the hash of the RBS collection
-    # @return [Hash{Array(String, String) => Array<Pin::Base>}] Indexed by gemspec name and version
-    def combined_pins_in_memory
-      self.class.all_combined_pins_in_memory
+    # Cache gem documentation if needed for this doc_map
+    #
+    # @param gemspec [Gem::Specification]
+    # @param rebuild [Boolean] whether to rebuild the pins even if they are cached
+    # @param out [IO, nil] output stream for logging
+    #
+    # @return [void]
+    def cache gemspec, rebuild: false, out: nil
+      pin_cache.cache_gem(gemspec: gemspec,
+                          rebuild: rebuild,
+                          out: out)
     end
 
-    # @return [Array<String>]
-    def yard_plugins
-      @environ.yard_plugins
-    end
+    private
 
-    # @return [Set<Gem::Specification>]
-    def dependencies
-      @dependencies ||= (gemspecs.flat_map { |spec| fetch_dependencies(spec) } - gemspecs).to_set
+    # @return [Array<Gem::Specification>]
+    def gemspecs
+      @gemspecs ||= required_gems_map.values.compact.flatten
     end
 
-    private
-
-    # @return [void]
-    def load_serialized_gem_pins
-      @pins = []
-      @uncached_yard_gemspecs = []
-      @uncached_rbs_collection_gemspecs = []
+    # @param out [IO, nil]
+    # @return [Array<Pin::Base>]
+    def load_serialized_gem_pins out: @out
+      serialized_pins = []
       with_gemspecs, without_gemspecs = required_gems_map.partition { |_, v| v }
+      # @sg-ignore Need Hash[] support
       # @type [Array<String>]
-      paths = Hash[without_gemspecs].keys
+      missing_paths = Hash[without_gemspecs].keys
       # @type [Array<Gem::Specification>]
-      gemspecs = Hash[with_gemspecs].values.flatten.compact + dependencies.to_a
-
-      paths.each do |path|
-        rbs_pins = deserialize_stdlib_rbs_map path
+      gemspecs = Hash[with_gemspecs].values.flatten.compact + dependencies(out: out).to_a
+
+      missing_paths.each do |path|
+        # this will load from disk if needed; no need to manage
+        # uncached_gemspecs to trigger that later
+        stdlib_name_guess = path.split('/').first
+
+        # try to resolve the stdlib name
+        deps = workspace.stdlib_dependencies(stdlib_name_guess) || []
+        [stdlib_name_guess, *deps].compact.each do |potential_stdlib_name|
+          rbs_pins = pin_cache.cache_stdlib_rbs_map potential_stdlib_name
+          serialized_pins.concat rbs_pins if rbs_pins
+        end
       end
 
-      logger.debug { "DocMap#load_serialized_gem_pins: Combining pins..." }
+      existing_pin_count = serialized_pins.length
       time = Benchmark.measure do
         gemspecs.each do |gemspec|
-          pins = deserialize_combined_pin_cache gemspec
-          @pins.concat pins if pins
+          # only deserializes already-cached gems
+          gemspec_pins = pin_cache.deserialize_combined_pin_cache gemspec
+          if gemspec_pins
+            serialized_pins.concat gemspec_pins
+          else
+            uncached_gemspecs << gemspec
+          end
         end
       end
-      logger.info { "DocMap#load_serialized_gem_pins: Loaded and processed serialized pins together in #{time.real} seconds" }
-      @uncached_yard_gemspecs.uniq!
-      @uncached_rbs_collection_gemspecs.uniq!
-      nil
+      pins_processed = serialized_pins.length - existing_pin_count
+      milliseconds = (time.real * 1000).round
+      if (milliseconds > 500) && out && gemspecs.any?
+        out.puts "Deserialized #{serialized_pins.length} gem pins from #{PinCache.base_dir} in #{milliseconds} ms"
+      end
+      uncached_gemspecs.uniq! { |gemspec| "#{gemspec.name}:#{gemspec.version}" }
+      serialized_pins
     end
 
     # @return [Hash{String => Array<Gem::Specification>}]
     def required_gems_map
-      @required_gems_map ||= requires.to_h { |path| [path, resolve_path_to_gemspecs(path)] }
-    end
-
-    # @return [Hash{String => Gem::Specification}]
-    def preference_map
-      @preference_map ||= preferences.to_h { |gemspec| [gemspec.name, gemspec] }
-    end
-
-    # @param gemspec [Gem::Specification]
-    # @return [Array<Pin::Base>]
-    def deserialize_yard_pin_cache gemspec
-      if yard_pins_in_memory.key?([gemspec.name, gemspec.version])
-        return yard_pins_in_memory[[gemspec.name, gemspec.version]]
-      end
-
-      cached = PinCache.deserialize_yard_gem(gemspec)
-      if cached
-        logger.info { "Loaded #{cached.length} cached YARD pins from #{gemspec.name}:#{gemspec.version}" }
-        yard_pins_in_memory[[gemspec.name, gemspec.version]] = cached
-        cached
-      else
-        logger.debug "No YARD pin cache for #{gemspec.name}:#{gemspec.version}"
-        @uncached_yard_gemspecs.push gemspec
-        nil
-      end
-    end
-
-    # @param gemspec [Gem::Specification]
-    # @return [void]
-    def deserialize_combined_pin_cache(gemspec)
-      unless combined_pins_in_memory[[gemspec.name, gemspec.version]].nil?
-        return combined_pins_in_memory[[gemspec.name, gemspec.version]]
-      end
-
-      rbs_map = RbsMap.from_gemspec(gemspec, rbs_collection_path, rbs_collection_config_path)
-      rbs_version_cache_key = rbs_map.cache_key
-
-      cached = PinCache.deserialize_combined_gem(gemspec, rbs_version_cache_key)
-      if cached
-        logger.info { "Loaded #{cached.length} cached YARD pins from #{gemspec.name}:#{gemspec.version}" }
-        combined_pins_in_memory[[gemspec.name, gemspec.version]] = cached
-        return combined_pins_in_memory[[gemspec.name, gemspec.version]]
-      end
-
-      rbs_collection_pins = deserialize_rbs_collection_cache gemspec, rbs_version_cache_key
-
-      yard_pins = deserialize_yard_pin_cache gemspec
-
-      if !rbs_collection_pins.nil? && !yard_pins.nil?
-        logger.debug { "Combining pins for #{gemspec.name}:#{gemspec.version}" }
-        combined_pins = GemPins.combine(yard_pins, rbs_collection_pins)
-        PinCache.serialize_combined_gem(gemspec, rbs_version_cache_key, combined_pins)
-        combined_pins_in_memory[[gemspec.name, gemspec.version]] = combined_pins
-        logger.info { "Generated #{combined_pins_in_memory[[gemspec.name, gemspec.version]].length} combined pins for #{gemspec.name} #{gemspec.version}" }
-        return combined_pins
-      end
-
-      if !yard_pins.nil?
-        logger.debug { "Using only YARD pins for #{gemspec.name}:#{gemspec.version}" }
-        combined_pins_in_memory[[gemspec.name, gemspec.version]] = yard_pins
-        return combined_pins_in_memory[[gemspec.name, gemspec.version]]
-      elsif !rbs_collection_pins.nil?
-        logger.debug { "Using only RBS collection pins for #{gemspec.name}:#{gemspec.version}" }
-        combined_pins_in_memory[[gemspec.name, gemspec.version]] = rbs_collection_pins
-        return combined_pins_in_memory[[gemspec.name, gemspec.version]]
-      else
-        logger.debug { "Pins not yet cached for #{gemspec.name}:#{gemspec.version}" }
-        return nil
-      end
-    end
-
-    # @param path [String] require path that might be in the RBS stdlib collection
-    # @return [void]
-    def deserialize_stdlib_rbs_map path
-      map = RbsMap::StdlibMap.load(path)
-      if map.resolved?
-        logger.debug { "Loading stdlib pins for #{path}" }
-        @pins.concat map.pins
-        logger.debug { "Loaded #{map.pins.length} stdlib pins for #{path}" }
-        map.pins
-      else
-        # @todo Temporarily ignoring unresolved `require 'set'`
-        logger.debug { "Require path #{path} could not be resolved in RBS" } unless path == 'set'
-        nil
-      end
-    end
-
-    # @param gemspec [Gem::Specification]
-    # @param rbs_version_cache_key [String]
-    # @return [Array<Pin::Base>, nil]
-    def deserialize_rbs_collection_cache gemspec, rbs_version_cache_key
-      return if rbs_collection_pins_in_memory.key?([gemspec, rbs_version_cache_key])
-      cached = PinCache.deserialize_rbs_collection_gem(gemspec, rbs_version_cache_key)
-      if cached
-        logger.info { "Loaded #{cached.length} pins from RBS collection cache for #{gemspec.name}:#{gemspec.version}" } unless cached.empty?
-        rbs_collection_pins_in_memory[[gemspec, rbs_version_cache_key]] = cached
-        cached
-      else
-        logger.debug "No RBS collection pin cache for #{gemspec.name} #{gemspec.version}"
-        @uncached_rbs_collection_gemspecs.push gemspec
-        nil
-      end
-    end
-
-    # @param path [String]
-    # @return [::Array<Gem::Specification>, nil]
-    def resolve_path_to_gemspecs path
-      return nil if path.empty?
-      return gemspecs_required_from_bundler if path == 'bundler/require'
-
-      # @type [Gem::Specification, nil]
-      gemspec = Gem::Specification.find_by_path(path)
-      if gemspec.nil?
-        gem_name_guess = path.split('/').first
-        begin
-          # this can happen when the gem is included via a local path in
-          # a Gemfile; Gem doesn't try to index the paths in that case.
-          #
-          # See if we can make a good guess:
-          potential_gemspec = Gem::Specification.find_by_name(gem_name_guess)
-          file = "lib/#{path}.rb"
-          gemspec = potential_gemspec if potential_gemspec.files.any? { |gemspec_file| file == gemspec_file }
-        rescue Gem::MissingSpecError
-          logger.debug { "Require path #{path} could not be resolved to a gem via find_by_path or guess of #{gem_name_guess}" }
-          []
-        end
-      end
-      return nil if gemspec.nil?
-      [gemspec_or_preference(gemspec)]
+      @required_gems_map ||= requires.to_h { |require| [require, workspace.resolve_require(require)] }
     end
 
-    # @param gemspec [Gem::Specification]
-    # @return [Gem::Specification]
-    def gemspec_or_preference gemspec
-      return gemspec unless preference_map.key?(gemspec.name)
-      return gemspec if gemspec.version == preference_map[gemspec.name].version
-
-      change_gemspec_version gemspec, preference_map[by_path.name].version
-    end
-
-    # @param gemspec [Gem::Specification]
-    # @param version [Gem::Version]
-    # @return [Gem::Specification]
-    def change_gemspec_version gemspec, version
-      Gem::Specification.find_by_name(gemspec.name, "= #{version}")
-    rescue Gem::MissingSpecError
-      Solargraph.logger.info "Gem #{gemspec.name} version #{version} not found. Using #{gemspec.version} instead"
-      gemspec
-    end
-
-    # @param gemspec [Gem::Specification]
-    # @return [Array<Gem::Specification>]
-    def fetch_dependencies gemspec
-      # @param spec [Gem::Dependency]
-      only_runtime_dependencies(gemspec).each_with_object(Set.new) do |spec, deps|
-        Solargraph.logger.info "Adding #{spec.name} dependency for #{gemspec.name}"
-        dep = Gem.loaded_specs[spec.name]
-        # @todo is next line necessary?
-        dep ||= Gem::Specification.find_by_name(spec.name, spec.requirement)
-        deps.merge fetch_dependencies(dep) if deps.add?(dep)
-      rescue Gem::MissingSpecError
-        Solargraph.logger.warn "Gem dependency #{spec.name} #{spec.requirement} for #{gemspec.name} not found in RubyGems."
-      end.to_a
-    end
-
-    # @param gemspec [Gem::Specification]
-    # @return [Array<Gem::Dependency>]
-    def only_runtime_dependencies gemspec
-      gemspec.dependencies - gemspec.development_dependencies
-    end
-
-
     def inspect
       self.class.inspect
     end
-
-    # @return [Array<Gem::Specification>]
-    def gemspecs_required_from_bundler
-      # @todo Handle projects with custom Bundler/Gemfile setups
-      return unless workspace.gemfile?
-
-      if workspace.gemfile? && Bundler.definition&.lockfile&.to_s&.start_with?(workspace.directory)
-        # Find only the gems bundler is now using
-        Bundler.definition.locked_gems.specs.flat_map do |lazy_spec|
-          logger.info "Handling #{lazy_spec.name}:#{lazy_spec.version}"
-          [Gem::Specification.find_by_name(lazy_spec.name, lazy_spec.version)]
-        rescue Gem::MissingSpecError => e
-          logger.info("Could not find #{lazy_spec.name}:#{lazy_spec.version} with find_by_name, falling back to guess")
-          # can happen in local filesystem references
-          specs = resolve_path_to_gemspecs lazy_spec.name
-          logger.warn "Gem #{lazy_spec.name} #{lazy_spec.version} from bundle not found: #{e}" if specs.nil?
-          next specs
-        end.compact
-      else
-        logger.info 'Fetching gemspecs required from Bundler (bundler/require)'
-        gemspecs_required_from_external_bundle
-      end
-    end
-
-    # @return [Array<Gem::Specification>]
-    def gemspecs_required_from_external_bundle
-      logger.info 'Fetching gemspecs required from external bundle'
-      return [] unless workspace&.directory
-
-      Solargraph.with_clean_env do
-        cmd = [
-          'ruby', '-e',
-          "require 'bundler'; require 'json'; Dir.chdir('#{workspace&.directory}') { puts Bundler.definition.locked_gems.specs.map { |spec| [spec.name, spec.version] }.to_h.to_json }"
-        ]
-        o, e, s = Open3.capture3(*cmd)
-        if s.success?
-          Solargraph.logger.debug "External bundle: #{o}"
-          hash = o && !o.empty? ? JSON.parse(o.split("\n").last) : {}
-          hash.flat_map do |name, version|
-            Gem::Specification.find_by_name(name, version)
-          rescue Gem::MissingSpecError => e
-            logger.info("Could not find #{name}:#{version} with find_by_name, falling back to guess")
-            # can happen in local filesystem references
-            specs = resolve_path_to_gemspecs name
-            logger.warn "Gem #{name} #{version} from bundle not found: #{e}" if specs.nil?
-            next specs
-          end.compact
-        else
-          Solargraph.logger.warn "Failed to load gems from bundle at #{workspace&.directory}: #{e}"
-        end
-      end
-    end
   end
 end
diff --git a/lib/solargraph/environ.rb b/lib/solargraph/environ.rb
index 3d24127c6..639442a04 100644
--- a/lib/solargraph/environ.rb
+++ b/lib/solargraph/environ.rb
@@ -22,7 +22,7 @@ class Environ
     # @param requires [Array<String>]
     # @param domains [Array<String>]
     # @param pins [Array<Pin::Base>]
-    # @param yard_plugins[Array<String>]
+    # @param yard_plugins [Array<String>]
     def initialize requires: [], domains: [], pins: [], yard_plugins: []
       @requires = requires
       @domains = domains
diff --git a/lib/solargraph/gem_pins.rb b/lib/solargraph/gem_pins.rb
index 43422505b..52714b373 100644
--- a/lib/solargraph/gem_pins.rb
+++ b/lib/solargraph/gem_pins.rb
@@ -12,20 +12,22 @@ class << self
     end
 
     # @param pins [Array<Pin::Base>]
-    # @return [Array<Pin::Base>]
+    # @return [Array<Pin::Method>]
     def self.combine_method_pins_by_path(pins)
       method_pins, alias_pins = pins.partition { |pin| pin.class == Pin::Method }
       by_path = method_pins.group_by(&:path)
-      by_path.transform_values! do |pins|
+      combined_by_path = by_path.transform_values do |pins|
         GemPins.combine_method_pins(*pins)
       end
-      by_path.values + alias_pins
+      combined_by_path.values + alias_pins
     end
 
-    # @param pins [Pin::Base]
-    # @return [Pin::Base, nil]
+    # @param pins [Array<Pin::Method>]
+    # @return [Pin::Method, nil]
     def self.combine_method_pins(*pins)
-      out = pins.reduce(nil) do |memo, pin|
+      # @type [Pin::Method, nil]
+      combined_pin = nil
+      out = pins.reduce(combined_pin) do |memo, pin|
         next pin if memo.nil?
         if memo == pin && memo.source != :combined
           # @todo we should track down situations where we are handled
@@ -39,33 +41,35 @@ def self.combine_method_pins(*pins)
       out
     end
 
-    # @param yard_plugins [Array<String>] The names of YARD plugins to use.
-    # @param gemspec [Gem::Specification]
-    # @return [Array<Pin::Base>]
-    def self.build_yard_pins(yard_plugins, gemspec)
-      Yardoc.cache(yard_plugins, gemspec) unless Yardoc.cached?(gemspec)
-      yardoc = Yardoc.load!(gemspec)
-      YardMap::Mapper.new(yardoc, gemspec).map
-    end
-
     # @param yard_pins [Array<Pin::Base>]
-    # @param rbs_map [RbsMap]
+    # @param rbs_pins [Array<Pin::Base>]
     # @return [Array<Pin::Base>]
     def self.combine(yard_pins, rbs_pins)
       in_yard = Set.new
-      rbs_api_map = Solargraph::ApiMap.new(pins: rbs_pins)
+      rbs_store = Solargraph::ApiMap::Store.new(rbs_pins)
       combined = yard_pins.map do |yard_pin|
+        rbs_pin = rbs_store.get_path_pins(yard_pin.path).filter { |pin| pin.is_a? Pin::Method }.first
+
+        next yard_pin unless rbs_pin && yard_pin.is_a?(Pin::Method)
+
         in_yard.add yard_pin.path
-        rbs_pin = rbs_api_map.get_path_pins(yard_pin.path).filter { |pin| pin.is_a? Pin::Method }.first
-        next yard_pin unless rbs_pin && yard_pin.class == Pin::Method
 
         unless rbs_pin
           logger.debug { "GemPins.combine: No rbs pin for #{yard_pin.path} - using YARD's '#{yard_pin.inspect} (return_type=#{yard_pin.return_type}; signatures=#{yard_pin.signatures})" }
           next yard_pin
         end
 
+        # at this point both yard_pins and rbs_pins are methods or
+        # method aliases.  if not plain methods, prefer the YARD one
+        next yard_pin if rbs_pin.class != Pin::Method
+
+        next rbs_pin if yard_pin.class != Pin::Method
+
+        # both are method pins
         out = combine_method_pins(rbs_pin, yard_pin)
-        logger.debug { "GemPins.combine: Combining yard.path=#{yard_pin.path} - rbs=#{rbs_pin.inspect} with yard=#{yard_pin.inspect} into #{out}" }
+        logger.debug do
+          "GemPins.combine: Combining yard.path=#{yard_pin.path} - rbs=#{rbs_pin.inspect} with yard=#{yard_pin.inspect} into #{out}"
+        end
         out
       end
       in_rbs_only = rbs_pins.select do |pin|
diff --git a/lib/solargraph/language_server/host.rb b/lib/solargraph/language_server/host.rb
index 1c5831bda..e85fc813a 100644
--- a/lib/solargraph/language_server/host.rb
+++ b/lib/solargraph/language_server/host.rb
@@ -299,6 +299,7 @@ def prepare directory, name = nil
         end
       end
 
+      # @return [String]
       def command_path
         options['commandPath'] || 'solargraph'
       end
@@ -716,7 +717,7 @@ def diagnoser
       # A hash of client requests by ID. The host uses this to keep track of
       # pending responses.
       #
-      # @return [Hash{Integer => Solargraph::LanguageServer::Host}]
+      # @return [Hash{Integer => Request}]
       def requests
         @requests ||= {}
       end
diff --git a/lib/solargraph/language_server/host/dispatch.rb b/lib/solargraph/language_server/host/dispatch.rb
index 1480e20a2..1ff1227b8 100644
--- a/lib/solargraph/language_server/host/dispatch.rb
+++ b/lib/solargraph/language_server/host/dispatch.rb
@@ -95,6 +95,7 @@ def implicit_library_for uri
           nil
         end
 
+        # @return [Hash{String => undefined}]
         def options
           @options ||= {}.freeze
         end
@@ -118,6 +119,7 @@ def generic_library
         end
 
         # @param library [Solargraph::Library]
+        # @param progress [Solargraph::LanguageServer::Progress, nil]
         # @return [void]
         def update progress
           progress&.send(self)
diff --git a/lib/solargraph/language_server/host/message_worker.rb b/lib/solargraph/language_server/host/message_worker.rb
index 482a40e56..ec426b99f 100644
--- a/lib/solargraph/language_server/host/message_worker.rb
+++ b/lib/solargraph/language_server/host/message_worker.rb
@@ -72,10 +72,12 @@ def tick
 
         private
 
+        # @return [Hash, nil]
         def next_message
           cancel_message || next_priority
         end
 
+        # @return [Hash, nil]
         def cancel_message
           # Handle cancellations first
           idx = messages.find_index { |msg| msg['method'] == '$/cancelRequest' }
@@ -86,6 +88,7 @@ def cancel_message
           msg
         end
 
+        # @return [Hash, nil]
         def next_priority
           # Prioritize updates and version-dependent messages for performance
           idx = messages.find_index do |msg|
diff --git a/lib/solargraph/language_server/message/base.rb b/lib/solargraph/language_server/message/base.rb
index fbc55ccbd..cc72d99b5 100644
--- a/lib/solargraph/language_server/message/base.rb
+++ b/lib/solargraph/language_server/message/base.rb
@@ -16,7 +16,7 @@ class Base
         # @return [String]
         attr_reader :method
 
-        # @return [Hash{String => Array<undefined>, Hash{String => undefined}, String, Integer}]
+        # @return [Hash{String => undefined}]
         attr_reader :params
 
         # @return [Hash, Array, nil]
@@ -79,6 +79,7 @@ def send_response
 
         private
 
+        # @return [void]
         def accept_or_cancel
           if host.cancel?(id)
             # https://microsoft.github.io/language-server-protocol/specifications/specification-current/#cancelRequest
diff --git a/lib/solargraph/language_server/message/extended/check_gem_version.rb b/lib/solargraph/language_server/message/extended/check_gem_version.rb
index 2e80f40c6..06892ed19 100644
--- a/lib/solargraph/language_server/message/extended/check_gem_version.rb
+++ b/lib/solargraph/language_server/message/extended/check_gem_version.rb
@@ -1,12 +1,6 @@
 # frozen_string_literal: true
 
 
-# @todo PR the RBS gem to add this
-# @!parse
-#   module ::Gem
-#    class SpecFetcher; end
-#   end
-
 module Solargraph
   module LanguageServer
     module Message
diff --git a/lib/solargraph/language_server/message/text_document/definition.rb b/lib/solargraph/language_server/message/text_document/definition.rb
index 47bf7a60d..5f143cc82 100644
--- a/lib/solargraph/language_server/message/text_document/definition.rb
+++ b/lib/solargraph/language_server/message/text_document/definition.rb
@@ -10,6 +10,7 @@ def process
 
     private
 
+    # @return [Array<Hash>]
     def code_location
       suggestions = host.definitions_at(params['textDocument']['uri'], @line, @column)
       return nil if suggestions.empty?
@@ -21,6 +22,7 @@ def code_location
       end
     end
 
+    # @return [Array<Hash>]
     def require_location
       # @todo Terrible hack
       lib = host.library_for(params['textDocument']['uri'])
diff --git a/lib/solargraph/language_server/message/text_document/type_definition.rb b/lib/solargraph/language_server/message/text_document/type_definition.rb
index 8143d7710..8c95c231e 100644
--- a/lib/solargraph/language_server/message/text_document/type_definition.rb
+++ b/lib/solargraph/language_server/message/text_document/type_definition.rb
@@ -10,6 +10,7 @@ def process
 
     private
 
+    # @return [Array<Hash>]
     def code_location
       suggestions = host.type_definitions_at(params['textDocument']['uri'], @line, @column)
       return nil if suggestions.empty?
diff --git a/lib/solargraph/language_server/message/workspace/did_change_workspace_folders.rb b/lib/solargraph/language_server/message/workspace/did_change_workspace_folders.rb
index 2e7b4130c..e1e83fc1e 100644
--- a/lib/solargraph/language_server/message/workspace/did_change_workspace_folders.rb
+++ b/lib/solargraph/language_server/message/workspace/did_change_workspace_folders.rb
@@ -9,11 +9,13 @@ def process
 
     private
 
+    # @return [void]
     def add_folders
       return unless params['event'] && params['event']['added']
       host.prepare_folders params['event']['added']
     end
 
+    # @return [void]
     def remove_folders
       return unless params['event'] && params['event']['removed']
       params['event']['removed'].each do |folder|
diff --git a/lib/solargraph/language_server/progress.rb b/lib/solargraph/language_server/progress.rb
index 0b2aac5fe..10900a37e 100644
--- a/lib/solargraph/language_server/progress.rb
+++ b/lib/solargraph/language_server/progress.rb
@@ -39,6 +39,7 @@ def initialize title
 
       # @param message [String]
       # @param percentage [Integer]
+      # @return [void]
       def begin message, percentage
         @kind = 'begin'
         @message = message
@@ -47,6 +48,7 @@ def begin message, percentage
 
       # @param message [String]
       # @param percentage [Integer]
+      # @return [void]
       def report message, percentage
         @kind = 'report'
         @message = message
@@ -54,6 +56,7 @@ def report message, percentage
       end
 
       # @param message [String]
+      # @return [void]
       def finish message
         @kind = 'end'
         @message = message
@@ -62,6 +65,7 @@ def finish message
       end
 
       # @param host [Solargraph::LanguageServer::Host]
+      # @return [void]
       def send host
         return unless host.client_supports_progress? && !finished?
 
@@ -91,6 +95,7 @@ def create host
         @status = CREATED
       end
 
+      # @return [Hash]
       def build
         {
           token: uuid,
@@ -101,6 +106,7 @@ def build
         }
       end
 
+      # @return [Hash]
       def build_value
         case kind
         when 'begin'
@@ -115,6 +121,7 @@ def build_value
       end
 
       # @param host [Host]
+      # @return [void]
       def keep_alive host
         mutex.synchronize { @last = Time.now }
         @keep_alive ||= Thread.new do
@@ -127,6 +134,7 @@ def keep_alive host
         end
       end
 
+      # @return [Mutex]
       def mutex
         @mutex ||= Mutex.new
       end
diff --git a/lib/solargraph/language_server/request.rb b/lib/solargraph/language_server/request.rb
index e9aea65eb..dcad7084d 100644
--- a/lib/solargraph/language_server/request.rb
+++ b/lib/solargraph/language_server/request.rb
@@ -16,6 +16,7 @@ def process result
         @block.call(result) unless @block.nil?
       end
 
+      # @return [void]
       def send_response
         # noop
       end
diff --git a/lib/solargraph/library.rb b/lib/solargraph/library.rb
index 72224f672..3e4849537 100644
--- a/lib/solargraph/library.rb
+++ b/lib/solargraph/library.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+require 'rubygems'
 require 'pathname'
 require 'observer'
 require 'open3'
@@ -259,11 +260,11 @@ def references_from filename, line, column, strip: false, only: false
           referenced&.path == pin.path
         end
         if pin.path == 'Class#new'
-          caller = cursor.chain.base.infer(api_map, clip.send(:block), clip.locals).first
+          caller = cursor.chain.base.infer(api_map, clip.send(:closure), clip.locals).first
           if caller.defined?
             found.select! do |loc|
               clip = api_map.clip_at(loc.filename, loc.range.start)
-              other = clip.send(:cursor).chain.base.infer(api_map, clip.send(:block), clip.locals).first
+              other = clip.send(:cursor).chain.base.infer(api_map, clip.send(:closure), clip.locals).first
               caller == other
             end
           else
@@ -273,12 +274,12 @@ def references_from filename, line, column, strip: false, only: false
         # HACK: for language clients that exclude special characters from the start of variable names
         if strip && match = cursor.word.match(/^[^a-z0-9_]+/i)
           found.map! do |loc|
-            Solargraph::Location.new(loc.filename, Solargraph::Range.from_to(loc.range.start.line, loc.range.start.column + match[0].length, loc.range.ending.line, loc.range.ending.column))
+            Solargraph::Location.new(loc.filename,
+                                     Solargraph::Range.from_to(loc.range.start.line, loc.range.start.column + match[0].length, loc.range.ending.line,
+                                                               loc.range.ending.column))
           end
         end
-        result.concat(found.sort do |a, b|
-          a.range.start.line <=> b.range.start.line
-        end)
+        result.concat(found.sort { |a, b| a.range.start.line <=> b.range.start.line })
       end
       result.uniq
     end
@@ -303,9 +304,7 @@ def locate_ref location
       return nil if pin.nil?
       # @param full [String]
       return_if_match = proc do |full|
-        if source_map_hash.key?(full)
-          return Location.new(full, Solargraph::Range.from_to(0, 0, 0, 0))
-        end
+        return Location.new(full, Solargraph::Range.from_to(0, 0, 0, 0)) if source_map_hash.key?(full)
       end
       workspace.require_paths.each do |path|
         full = File.join path, pin.name
@@ -402,8 +401,8 @@ def diagnose filename
       repargs = {}
       workspace.config.reporters.each do |line|
         if line == 'all!'
-          Diagnostics.reporters.each do |reporter|
-            repargs[reporter] ||= []
+          Diagnostics.reporters.each do |reporter_name|
+            repargs[Diagnostics.reporter(reporter_name)] ||= []
           end
         else
           args = line.split(':').map(&:strip)
@@ -500,7 +499,12 @@ def external_requires
 
     private
 
-    # @return [Hash{String => Set<String>}]
+    # @return [PinCache]
+    def pin_cache
+      workspace.pin_cache
+    end
+
+    # @return [Hash{String => Array<String>}]
     def source_map_external_require_hash
       @source_map_external_require_hash ||= {}
     end
@@ -508,6 +512,7 @@ def source_map_external_require_hash
     # @param source_map [SourceMap]
     # @return [void]
     def find_external_requires source_map
+      # @type [Set<String>]
       new_set = source_map.requires.map(&:name).to_set
       # return if new_set == source_map_external_require_hash[source_map.filename]
       _filenames = nil
@@ -579,12 +584,13 @@ def cache_errors
     def cache_next_gemspec
       return if @cache_progress
 
+      # @type [Gem::Specification]
       spec = cacheable_specs.first
       return end_cache_progress unless spec
 
       pending = api_map.uncached_gemspecs.length - cache_errors.length - 1
 
-      if Yardoc.processing?(spec)
+      if pin_cache.yardoc_processing?(spec)
         logger.info "Enqueuing cache of #{spec.name} #{spec.version} (already being processed)"
         queued_gemspec_cache.push(spec)
         return if pending - queued_gemspec_cache.length < 1
@@ -595,7 +601,10 @@ def cache_next_gemspec
         logger.info "Caching #{spec.name} #{spec.version}"
         Thread.new do
           report_cache_progress spec.name, pending
-          _o, e, s = Open3.capture3(workspace.command_path, 'cache', spec.name, spec.version.to_s)
+          kwargs = {}
+          kwargs[:chdir] = workspace.directory.to_s if workspace.directory && !workspace.directory.empty?
+          _o, e, s = Open3.capture3(workspace.command_path, 'cache', spec.name, spec.version.to_s,
+                                    **kwargs)
           if s.success?
             logger.info "Cached #{spec.name} #{spec.version}"
           else
@@ -612,8 +621,7 @@ def cache_next_gemspec
 
     # @return [Array<Gem::Specification>]
     def cacheable_specs
-      cacheable = api_map.uncached_yard_gemspecs +
-                  api_map.uncached_rbs_collection_gemspecs -
+      cacheable = api_map.uncached_gemspecs +
                   queued_gemspec_cache -
                   cache_errors.to_a
       return cacheable unless cacheable.empty?
@@ -672,8 +680,7 @@ def sync_catalog
         source_map_hash.values.each { |map| find_external_requires(map) }
         api_map.catalog bench
         logger.info "Catalog complete (#{api_map.source_maps.length} files, #{api_map.pins.length} pins)"
-        logger.info "#{api_map.uncached_yard_gemspecs.length} uncached YARD gemspecs"
-        logger.info "#{api_map.uncached_rbs_collection_gemspecs.length} uncached RBS collection gemspecs"
+        logger.info "#{api_map.uncached_gemspecs.length} uncached gemspecs"
         cache_next_gemspec
         @sync_count = 0
       end
diff --git a/lib/solargraph/location.rb b/lib/solargraph/location.rb
index 74d1318df..444fc0659 100644
--- a/lib/solargraph/location.rb
+++ b/lib/solargraph/location.rb
@@ -7,29 +7,31 @@ module Solargraph
   class Location
     include Equality
 
-    # @return [String]
+    # @return [String, nil]
     attr_reader :filename
 
     # @return [Solargraph::Range]
     attr_reader :range
 
-    # @param filename [String]
+    # @param filename [String, nil]
     # @param range [Solargraph::Range]
     def initialize filename, range
       @filename = filename
       @range = range
     end
 
-    # @sg-ignore Fix "Not enough arguments to Module#protected"
     protected def equality_fields
       [filename, range]
     end
 
+    # @param other [self]
     def <=>(other)
       return nil unless other.is_a?(Location)
       if filename == other.filename
         range <=> other.range
       else
+        return -1 if filename.nil?
+        return 1 if other.filename.nil?
         filename <=> other.filename
       end
     end
@@ -60,6 +62,7 @@ def to_hash
     end
 
     # @param node [Parser::AST::Node, nil]
+    # @return [self, nil]
     def self.from_node(node)
       return nil if node.nil? || node.loc.nil?
       range = Range.from_node(node)
diff --git a/lib/solargraph/logging.rb b/lib/solargraph/logging.rb
index a8bc3b3ee..f26867db3 100644
--- a/lib/solargraph/logging.rb
+++ b/lib/solargraph/logging.rb
@@ -30,9 +30,26 @@ module Logging
 
     module_function
 
+    # override this in your class to temporarily set a custom
+    # filtering log level for the class (e.g., suppress any debug
+    # message by setting it to :info even if it is set elsewhere, or
+    # show existing debug messages by setting to :debug).
+    #
+    # @return [Symbol]
+    def log_level
+      :warn
+    end
+
     # @return [Logger]
     def logger
-      @@logger
+      if LOG_LEVELS[log_level.to_s] == DEFAULT_LOG_LEVEL
+        @@logger
+      else
+        new_log_level = LOG_LEVELS[log_level.to_s]
+        logger = Logger.new(STDERR, level: new_log_level)
+        logger.formatter = @@logger.formatter
+        logger
+      end
     end
   end
 end
diff --git a/lib/solargraph/parser/comment_ripper.rb b/lib/solargraph/parser/comment_ripper.rb
index e74fcb259..92373df20 100644
--- a/lib/solargraph/parser/comment_ripper.rb
+++ b/lib/solargraph/parser/comment_ripper.rb
@@ -3,6 +3,13 @@
 module Solargraph
   module Parser
     class CommentRipper < Ripper::SexpBuilderPP
+      # @!override Ripper::SexpBuilder#on_embdoc_beg
+      #   @return [Array(Symbol, String, Array)]
+      # @!override Ripper::SexpBuilder#on_embdoc
+      #   @return [Array(Symbol, String, Array)]
+      # @!override Ripper::SexpBuilder#on_embdoc_end
+      #   @return [Array(Symbol, String, Array)]
+
       # @param src [String]
       # @param filename [String]
       # @param lineno [Integer]
diff --git a/lib/solargraph/parser/flow_sensitive_typing.rb b/lib/solargraph/parser/flow_sensitive_typing.rb
index 308db214b..4c80d3dea 100644
--- a/lib/solargraph/parser/flow_sensitive_typing.rb
+++ b/lib/solargraph/parser/flow_sensitive_typing.rb
@@ -15,7 +15,9 @@ def initialize(locals, enclosing_breakable_pin = nil)
       #
       # @return [void]
       def process_and(and_node, true_ranges = [])
+        # @type [Parser::AST::Node]
         lhs = and_node.children[0]
+        # @type [Parser::AST::Node]
         rhs = and_node.children[1]
 
         before_rhs_loc = rhs.location.expression.adjust(begin_pos: -1)
@@ -42,7 +44,9 @@ def process_if(if_node)
         #   s(:send, nil, :bar))
         # [4] pry(main)>
         conditional_node = if_node.children[0]
+        # @type [Parser::AST::Node]
         then_clause = if_node.children[1]
+        # @type [Parser::AST::Node]
         else_clause = if_node.children[2]
 
         true_ranges = []
@@ -156,6 +160,7 @@ def process_facts(facts_by_pin, presences)
 
       # @param conditional_node [Parser::AST::Node]
       # @param true_ranges [Array<Range>]
+      # @return [void]
       def process_conditional(conditional_node, true_ranges)
         if conditional_node.type == :send
           process_isa(conditional_node, true_ranges)
diff --git a/lib/solargraph/parser/node_methods.rb b/lib/solargraph/parser/node_methods.rb
deleted file mode 100644
index 5d3d1079a..000000000
--- a/lib/solargraph/parser/node_methods.rb
+++ /dev/null
@@ -1,97 +0,0 @@
-module Solargraph
-  module Parser
-    module NodeMethods
-      module_function
-
-      # @abstract
-      # @param node [Parser::AST::Node]
-      # @return [String]
-      def unpack_name node
-        raise NotImplementedError
-      end
-
-      # @abstract
-      # @todo Temporarily here for testing. Move to Solargraph::Parser.
-      # @param node [Parser::AST::Node]
-      # @return [Array<Parser::AST::Node>]
-      def call_nodes_from node
-        raise NotImplementedError
-      end
-
-      # Find all the nodes within the provided node that potentially return a
-      # value.
-      #
-      # The node parameter typically represents a method's logic, e.g., the
-      # second child (after the :args node) of a :def node. A simple one-line
-      # method would typically return itself, while a node with conditions
-      # would return the resulting node from each conditional branch. Nodes
-      # that follow a :return node are assumed to be unreachable. Nil values
-      # are converted to nil node types.
-      #
-      # @abstract
-      # @param node [Parser::AST::Node]
-      # @return [Array<Parser::AST::Node>]
-      def returns_from_method_body node
-        raise NotImplementedError
-      end
-
-      # @abstract
-      # @param node [Parser::AST::Node]
-      #
-      # @return [Array<Parser::AST::Node>]
-      def const_nodes_from node
-        raise NotImplementedError
-      end
-
-      # @abstract
-      # @param cursor [Solargraph::Source::Cursor]
-      # @return [Parser::AST::Node, nil]
-      def find_recipient_node cursor
-        raise NotImplementedError
-      end
-
-      # @abstract
-      # @param node [Parser::AST::Node]
-      # @return [Array<AST::Node>] low-level value nodes in
-      #   value position.  Does not include explicit return
-      #   statements
-      def value_position_nodes_only(node)
-        raise NotImplementedError
-      end
-
-      # @abstract
-      # @param nodes [Enumerable<Parser::AST::Node>]
-      def any_splatted_call?(nodes)
-        raise NotImplementedError
-      end
-
-      # @abstract
-      # @param node [Parser::AST::Node]
-      # @return [void]
-      def process node
-        raise NotImplementedError
-      end
-
-      # @abstract
-      # @param node [Parser::AST::Node]
-      # @return [Hash{Parser::AST::Node => Source::Chain}]
-      def convert_hash node
-        raise NotImplementedError
-      end
-
-      # @abstract
-      # @param node [Parser::AST::Node]
-      # @return [Position]
-      def get_node_start_position(node)
-        raise NotImplementedError
-      end
-
-      # @abstract
-      # @param node [Parser::AST::Node]
-      # @return [Position]
-      def get_node_end_position(node)
-        raise NotImplementedError
-      end
-    end
-  end
-end
diff --git a/lib/solargraph/parser/node_processor.rb b/lib/solargraph/parser/node_processor.rb
index a55b7120b..347240309 100644
--- a/lib/solargraph/parser/node_processor.rb
+++ b/lib/solargraph/parser/node_processor.rb
@@ -9,7 +9,7 @@ module NodeProcessor
       autoload :Base, 'solargraph/parser/node_processor/base'
 
       class << self
-        # @type [Hash<Symbol, Array<Class<NodeProcessor::Base>>>]
+        # @type [Hash{Symbol => Array<Class<NodeProcessor::Base>>}]
         @@processors ||= {}
 
         # Register a processor for a node type. You can register multiple processors for the same type.
@@ -17,12 +17,15 @@ class << self
         #
         # @param type [Symbol]
         # @param cls [Class<NodeProcessor::Base>]
-        # @return [Class<NodeProcessor::Base>]
+        # @return [Array<Class<NodeProcessor::Base>>]
         def register type, cls
           @@processors[type] ||= []
           @@processors[type] << cls
         end
 
+        # @param type [Symbol]
+        # @param cls [Class<NodeProcessor::Base>]
+        # @return [void]
         def deregister type, cls
           @@processors[type].delete(cls)
         end
@@ -31,7 +34,7 @@ def deregister type, cls
       # @param node [Parser::AST::Node]
       # @param region [Region]
       # @param pins [Array<Pin::Base>]
-      # @param locals [Array<Pin::BaseVariable>]
+      # @param locals [Array<Pin::LocalVariable>]
       # @return [Array(Array<Pin::Base>, Array<Pin::Base>)]
       def self.process node, region = Region.new, pins = [], locals = []
         if pins.empty?
diff --git a/lib/solargraph/parser/node_processor/base.rb b/lib/solargraph/parser/node_processor/base.rb
index d87268a91..fad31e95b 100644
--- a/lib/solargraph/parser/node_processor/base.rb
+++ b/lib/solargraph/parser/node_processor/base.rb
@@ -13,7 +13,7 @@ class Base
         # @return [Array<Pin::Base>]
         attr_reader :pins
 
-        # @return [Array<Pin::BaseVariable>]
+        # @return [Array<Pin::LocalVariable>]
         attr_reader :locals
 
         # @param node [Parser::AST::Node]
diff --git a/lib/solargraph/parser/parser_gem/class_methods.rb b/lib/solargraph/parser/parser_gem/class_methods.rb
index ddc742bd8..de1110ac9 100644
--- a/lib/solargraph/parser/parser_gem/class_methods.rb
+++ b/lib/solargraph/parser/parser_gem/class_methods.rb
@@ -1,15 +1,8 @@
 # frozen_string_literal: true
 
 require 'prism'
-
-# Awaiting ability to use a version containing https://github.com/whitequark/parser/pull/1076
-#
-# @!parse
-#   class ::Parser::Base < ::Parser::Builder
-#     # @return [Integer]
-#     def version; end
-#   end
-#   class ::Parser::CurrentRuby < ::Parser::Base; end
+require 'ast'
+require 'parser'
 
 module Solargraph
   module Parser
@@ -81,9 +74,10 @@ def references source, name
         end
 
         # @param name [String]
-        # @param top [AST::Node]
-        # @return [Array<AST::Node>]
+        # @param top [Parser::AST::Node]
+        # @return [Array<Parser::AST::Node>]
         def inner_node_references name, top
+          # @type [Array<Parser::AST::Node>]
           result = []
           if top.is_a?(AST::Node) && top.to_s.include?(":#{name}")
             result.push top if top.children.any? { |c| c.to_s == name }
@@ -118,7 +112,7 @@ def version
           parser.version
         end
 
-        # @param node [BasicObject]
+        # @param node [Object]
         # @return [Boolean]
         def is_ast_node? node
           node.is_a?(::Parser::AST::Node)
@@ -137,9 +131,7 @@ def node_range node
         def string_ranges node
           return [] unless is_ast_node?(node)
           result = []
-          if node.type == :str
-            result.push Range.from_node(node)
-          end
+          result.push Range.from_node(node) if node.type == :str
           node.children.each do |child|
             result.concat string_ranges(child)
           end
diff --git a/lib/solargraph/parser/parser_gem/flawed_builder.rb b/lib/solargraph/parser/parser_gem/flawed_builder.rb
index b5750413d..acf665e16 100644
--- a/lib/solargraph/parser/parser_gem/flawed_builder.rb
+++ b/lib/solargraph/parser/parser_gem/flawed_builder.rb
@@ -9,6 +9,7 @@ module ParserGem
       class FlawedBuilder < ::Parser::Builders::Default
         # @param token [::Parser::AST::Node]
         # @return [String]
+        # @sg-ignore
         def string_value(token)
           value(token)
         end
diff --git a/lib/solargraph/parser/parser_gem/node_chainer.rb b/lib/solargraph/parser/parser_gem/node_chainer.rb
index 646e753d5..d8d46319b 100644
--- a/lib/solargraph/parser/parser_gem/node_chainer.rb
+++ b/lib/solargraph/parser/parser_gem/node_chainer.rb
@@ -99,7 +99,8 @@ def generate_links n
           elsif [:gvar, :gvasgn].include?(n.type)
             result.push Chain::GlobalVariable.new(n.children[0].to_s)
           elsif n.type == :or_asgn
-            result.concat generate_links n.children[1]
+            new_node = n.updated(n.children[0].type, n.children[0].children + [n.children[1]])
+            result.concat generate_links new_node
           elsif [:class, :module, :def, :defs].include?(n.type)
             # @todo Undefined or what?
             result.push Chain::UNDEFINED_CALL
diff --git a/lib/solargraph/parser/parser_gem/node_methods.rb b/lib/solargraph/parser/parser_gem/node_methods.rb
index b716b352d..45eb038e2 100644
--- a/lib/solargraph/parser/parser_gem/node_methods.rb
+++ b/lib/solargraph/parser/parser_gem/node_methods.rb
@@ -3,20 +3,6 @@
 require 'parser'
 require 'ast'
 
-# Teach AST::Node#children about its generic type
-#
-# @todo contribute back to https://github.com/ruby/gem_rbs_collection/blob/main/gems/ast/2.4/ast.rbs
-#
-# @!parse
-#   module ::AST
-#     class Node
-#       # New children
-#
-#       # @return [Array<self, Integer, String, Symbol, nil>]
-#       attr_reader :children
-#     end
-#   end
-
 # https://github.com/whitequark/parser
 module Solargraph
   module Parser
@@ -120,7 +106,7 @@ def drill_signature node, signature
         end
 
         # @param node [Parser::AST::Node]
-        # @return [Hash{Parser::AST::Node => Chain}]
+        # @return [Hash{Parser::AST::Node, Symbol => Source::Chain}]
         def convert_hash node
           return {} unless Parser.is_ast_node?(node)
           return convert_hash(node.children[0]) if node.type == :kwsplat
@@ -179,6 +165,7 @@ def call_nodes_from node
             node.children[1..-1].each { |child| result.concat call_nodes_from(child) }
           elsif node.type == :send
             result.push node
+            result.concat call_nodes_from(node.children.first)
             node.children[2..-1].each { |child| result.concat call_nodes_from(child) }
           elsif [:super, :zsuper].include?(node.type)
             result.push node
@@ -232,6 +219,7 @@ def find_recipient_node cursor
           else
             source.tree_at(position.line, position.column - 1)
           end
+          # @type [AST::Node, nil]
           prev = nil
           tree.each do |node|
             if node.type == :send
@@ -345,7 +333,7 @@ def value_position_nodes_only(node)
             # Look at known control statements and use them to find
             # more specific return nodes.
             #
-            # @param node [Parser::AST::Node] Statement which is in
+            # @param node [AST::Node] Statement which is in
             #    value position for a method body
             # @param include_explicit_returns [Boolean] If true,
             #    include the value nodes of the parameter of the
diff --git a/lib/solargraph/parser/parser_gem/node_processors/block_node.rb b/lib/solargraph/parser/parser_gem/node_processors/block_node.rb
index 70a2d9e68..d773e8e50 100644
--- a/lib/solargraph/parser/parser_gem/node_processors/block_node.rb
+++ b/lib/solargraph/parser/parser_gem/node_processors/block_node.rb
@@ -19,7 +19,7 @@ def process
             else
               region.closure
             end
-            pins.push Solargraph::Pin::Block.new(
+            block_pin = Solargraph::Pin::Block.new(
               location: location,
               closure: parent,
               node: node,
@@ -28,7 +28,8 @@ def process
               scope: region.scope || region.closure.context.scope,
               source: :parser
             )
-            process_children region.update(closure: pins.last)
+            pins.push block_pin
+            process_children region.update(closure: block_pin)
           end
 
           private
diff --git a/lib/solargraph/parser/parser_gem/node_processors/if_node.rb b/lib/solargraph/parser/parser_gem/node_processors/if_node.rb
index 5784afcbe..2452b9cc5 100644
--- a/lib/solargraph/parser/parser_gem/node_processors/if_node.rb
+++ b/lib/solargraph/parser/parser_gem/node_processors/if_node.rb
@@ -11,6 +11,8 @@ def process
             process_children
 
             position = get_node_start_position(node)
+            # @sg-ignore
+            # @type [Solargraph::Pin::Breakable, nil]
             enclosing_breakable_pin = pins.select{|pin| pin.is_a?(Pin::Breakable) && pin.location.range.contain?(position)}.last
             FlowSensitiveTyping.new(locals, enclosing_breakable_pin).process_if(node)
           end
diff --git a/lib/solargraph/parser/parser_gem/node_processors/send_node.rb b/lib/solargraph/parser/parser_gem/node_processors/send_node.rb
index 8a70a0b3f..8490fd9b0 100644
--- a/lib/solargraph/parser/parser_gem/node_processors/send_node.rb
+++ b/lib/solargraph/parser/parser_gem/node_processors/send_node.rb
@@ -8,32 +8,41 @@ class SendNode < Parser::NodeProcessor::Base
           include ParserGem::NodeMethods
 
           def process
+            # @sg-ignore
+            # @type [Symbol]
+            method_name = node.children[1]
+            # :nocov:
+            unless method_name.instance_of?(Symbol)
+              Solargraph.assert_or_log(:parser_method_name, "Expected method name to be a Symbol, got #{method_name.class} for node #{node.inspect}")
+              return process_children
+            end
+            # :nocov:
             if node.children[0].nil?
-              if [:private, :public, :protected].include?(node.children[1])
+              if [:private, :public, :protected].include?(method_name)
                 process_visibility
-              elsif node.children[1] == :module_function
+              elsif method_name == :module_function
                 process_module_function
-              elsif [:attr_reader, :attr_writer, :attr_accessor].include?(node.children[1])
+              elsif [:attr_reader, :attr_writer, :attr_accessor].include?(method_name)
                 process_attribute
-              elsif node.children[1] == :include
+              elsif method_name == :include
                 process_include
-              elsif node.children[1] == :extend
+              elsif method_name == :extend
                 process_extend
-              elsif node.children[1] == :prepend
+              elsif method_name == :prepend
                 process_prepend
-              elsif node.children[1] == :require
+              elsif method_name == :require
                 process_require
-              elsif node.children[1] == :autoload
+              elsif method_name == :autoload
                 process_autoload
-              elsif node.children[1] == :private_constant
+              elsif method_name == :private_constant
                 process_private_constant
-              elsif node.children[1] == :alias_method && node.children[2] && node.children[2] && node.children[2].type == :sym && node.children[3] && node.children[3].type == :sym
+              elsif method_name == :alias_method && node.children[2] && node.children[2] && node.children[2].type == :sym && node.children[3] && node.children[3].type == :sym
                 process_alias_method
-              elsif node.children[1] == :private_class_method && node.children[2].is_a?(AST::Node)
+              elsif method_name == :private_class_method && node.children[2].is_a?(AST::Node)
                 # Processing a private class can potentially handle children on its own
                 return if process_private_class_method
               end
-            elsif node.children[1] == :require && node.children[0].to_s == '(const nil :Bundler)'
+            elsif method_name == :require && node.children[0].to_s == '(const nil :Bundler)'
               pins.push Pin::Reference::Require.new(Solargraph::Location.new(region.filename, Solargraph::Range.from_to(0, 0, 0, 0)), 'bundler/require', source: :parser)
             end
             process_children
@@ -45,15 +54,24 @@ def process
           def process_visibility
             if (node.children.length > 2)
               node.children[2..-1].each do |child|
+                # @sg-ignore
+                # @type [Symbol]
+                visibility = node.children[1]
+                # :nocov:
+                unless visibility.instance_of?(Symbol)
+                  Solargraph.assert_or_log(:parser_visibility, "Expected visibility name to be a Symbol, got #{visibility.class} for node #{node.inspect}")
+                  return process_children
+                end
+                # :nocov:
                 if child.is_a?(AST::Node) && (child.type == :sym || child.type == :str)
                   name = child.children[0].to_s
                   matches = pins.select{ |pin| pin.is_a?(Pin::Method) && pin.name == name && pin.namespace == region.closure.full_context.namespace && pin.context.scope == (region.scope || :instance)}
                   matches.each do |pin|
                     # @todo Smelly instance variable access
-                    pin.instance_variable_set(:@visibility, node.children[1])
+                    pin.instance_variable_set(:@visibility, visibility)
                   end
                 else
-                  process_children region.update(visibility: node.children[1])
+                  process_children region.update(visibility: visibility)
                 end
               end
             else
diff --git a/lib/solargraph/parser/region.rb b/lib/solargraph/parser/region.rb
index 8280c99b6..a6559bc8a 100644
--- a/lib/solargraph/parser/region.rb
+++ b/lib/solargraph/parser/region.rb
@@ -23,8 +23,10 @@ class Region
 
       # @param source [Source]
       # @param namespace [String]
+      # @param closure [Pin::Closure, nil]
       # @param scope [Symbol, nil]
       # @param visibility [Symbol]
+      # @param lvars [Array<Symbol>]
       def initialize source: Solargraph::Source.load_string(''), closure: nil,
                      scope: nil, visibility: :public, lvars: []
         @source = source
@@ -45,6 +47,7 @@ def filename
       # @param closure [Pin::Closure, nil]
       # @param scope [Symbol, nil]
       # @param visibility [Symbol, nil]
+      # @param lvars [Array<Symbol>, nil]
       # @return [Region]
       def update closure: nil, scope: nil, visibility: nil, lvars: nil
         Region.new(
diff --git a/lib/solargraph/parser/snippet.rb b/lib/solargraph/parser/snippet.rb
index d28c57c8c..1ea6bd6d9 100644
--- a/lib/solargraph/parser/snippet.rb
+++ b/lib/solargraph/parser/snippet.rb
@@ -1,11 +1,13 @@
 module Solargraph
   module Parser
     class Snippet
-      # @return [Range]
+      # @return [Solargraph::Range]
       attr_reader :range
       # @return [String]
       attr_reader :text
 
+      # @param range [Solargraph::Range]
+      # @param text [String]
       def initialize range, text
         @range = range
         @text = text
diff --git a/lib/solargraph/pin/base.rb b/lib/solargraph/pin/base.rb
index fb3274dab..0ce9902f5 100644
--- a/lib/solargraph/pin/base.rb
+++ b/lib/solargraph/pin/base.rb
@@ -69,8 +69,15 @@ def assert_location_provided
         Solargraph.assert_or_log(:best_location, "Neither location nor type_location provided - #{path} #{source} #{self.class}")
       end
 
+      # @return [Pin::Closure, nil]
+      def closure
+        Solargraph.assert_or_log(:closure, "Closure not set on #{self.class} #{name.inspect} from #{source.inspect}") unless @closure
+        # @type [Pin::Closure, nil]
+        @closure
+      end
+
       # @param other [self]
-      # @param attrs [Hash{Symbol => Object}]
+      # @param attrs [Hash{::Symbol => Object}]
       #
       # @return [self]
       def combine_with(other, attrs={})
@@ -182,15 +189,19 @@ def combine_return_type(other)
           other.return_type
         elsif other.return_type.undefined?
           return_type
+        elsif return_type.erased_version_of?(other.return_type)
+          other.return_type
+        elsif other.return_type.erased_version_of?(return_type)
+          return_type
         elsif dodgy_return_type_source? && !other.dodgy_return_type_source?
           other.return_type
         elsif other.dodgy_return_type_source? && !dodgy_return_type_source?
           return_type
         else
           all_items = return_type.items + other.return_type.items
-          if all_items.any? { |item| item.selfy? } && all_items.any? { |item| item.rooted_tag == context.rooted_tag }
+          if all_items.any? { |item| item.selfy? } && all_items.any? { |item| item.rooted_namespace == context.rooted_namespace }
             # assume this was a declaration that should have said 'self'
-            all_items.delete_if { |item| item.rooted_tag == context.rooted_tag }
+            all_items.delete_if { |item| item.rooted_namespace == context.rooted_namespace }
           end
           ComplexType.new(all_items)
         end
@@ -218,7 +229,7 @@ def choose(other, attr)
       end
 
       # @param other [self]
-      # @param attr [Symbol]
+      # @param attr [::Symbol]
       # @sg-ignore
       # @return [undefined]
       def choose_node(other, attr)
@@ -298,9 +309,15 @@ def assert_same_count(other, attr)
       # @param other [self]
       # @param attr [::Symbol]
       #
-      # @return [Object, nil]
+      # @sg-ignore
+      # @return [undefined]
       def assert_same(other, attr)
-        return false if other.nil?
+        # :nocov:
+        if other.nil?
+          Solargraph.assert_or_log("combine_with_#{attr}".to_sym, "Sent nil for comparison")
+          return send(attr)
+        end
+        # :nocov:
         val1 = send(attr)
         val2 = other.send(attr)
         return val1 if val1 == val2
@@ -329,6 +346,8 @@ def choose_pin_attr_with_same_name(other, attr)
 
       # @param other [self]
       # @param attr [::Symbol]
+      #
+      # @sg-ignore Missing @return tag for Solargraph::Pin::Base#choose_pin_attr
       # @return [undefined]
       def choose_pin_attr(other, attr)
         # @type [Pin::Base, nil]
@@ -336,11 +355,14 @@ def choose_pin_attr(other, attr)
         # @type [Pin::Base, nil]
         val2 = other.send(attr)
         if val1.class != val2.class
+          # :nocov:
           Solargraph.assert_or_log("combine_with_#{attr}_class".to_sym,
                                    "Inconsistent #{attr.inspect} class values between \nself =#{inspect} and \nother=#{other.inspect}:\n\n self.#{attr} = #{val1.inspect}\nother.#{attr} = #{val2.inspect}")
           return val1
+          # :nocov:
         end
         # arbitrary way of choosing a pin
+        # @sg-ignore Need _1 support
         [val1, val2].compact.min_by { _1.best_location.to_s }
       end
 
diff --git a/lib/solargraph/pin/callable.rb b/lib/solargraph/pin/callable.rb
index 20d2301eb..4b0f45fdf 100644
--- a/lib/solargraph/pin/callable.rb
+++ b/lib/solargraph/pin/callable.rb
@@ -21,10 +21,13 @@ def initialize block: nil, return_type: nil, parameters: [], **splat
         @parameters = parameters
       end
 
+      # @return [String]
       def method_namespace
         closure.namespace
       end
 
+      # @param other [self]
+      # @return [Solargraph::Pin::Signature, nil]
       def combine_blocks(other)
         if block.nil?
           other.block
@@ -57,6 +60,8 @@ def generics
         []
       end
 
+      # @param other [self]
+      # @return [::Array<Parameter>]
       def choose_parameters(other)
         raise "Trying to combine two pins with different arities - \nself =#{inspect}, \nother=#{other.inspect}, \n\n self.arity=#{self.arity}, \nother.arity=#{other.arity}" if other.arity != arity
         parameters.zip(other.parameters).map do |param, other_param|
@@ -70,6 +75,7 @@ def choose_parameters(other)
         end
       end
 
+      # @return [Array<Pin::Parameter>]
       def blockless_parameters
         if parameters.last&.block?
           parameters[0..-2]
@@ -78,6 +84,7 @@ def blockless_parameters
         end
       end
 
+      # @return [Array]
       def arity
         [generics, blockless_parameters.map(&:arity_decl), block&.arity]
       end
@@ -125,6 +132,7 @@ def typify api_map
         end
       end
 
+      # @return [String]
       def method_name
         raise "closure was nil in #{self.inspect}" if closure.nil?
         @method_name ||= closure.name
@@ -197,6 +205,12 @@ def arity_matches? arguments, with_block
         true
       end
 
+      def reset_generated!
+        super
+        @parameters.each(&:reset_generated!)
+      end
+
+      # @return [Integer]
       def mandatory_positional_param_count
         parameters.count(&:arg?)
       end
diff --git a/lib/solargraph/pin/closure.rb b/lib/solargraph/pin/closure.rb
index 551ba5522..2d87bad07 100644
--- a/lib/solargraph/pin/closure.rb
+++ b/lib/solargraph/pin/closure.rb
@@ -8,6 +8,7 @@ class Closure < Base
 
       # @param scope [::Symbol] :class or :instance
       # @param generics [::Array<Pin::Parameter>, nil]
+      # @param generic_defaults [Hash{String => ComplexType}]
       def initialize scope: :class, generics: nil, generic_defaults: {},  **splat
         super(**splat)
         @scope = scope
@@ -15,6 +16,7 @@ def initialize scope: :class, generics: nil, generic_defaults: {},  **splat
         @generic_defaults = generic_defaults
       end
 
+      # @return [Hash{String => ComplexType}]
       def generic_defaults
         @generic_defaults ||= {}
       end
@@ -46,6 +48,10 @@ def binder
         @binder || context
       end
 
+      # @param api_map [Solargraph::ApiMap]
+      # @return [void]
+      def rebind api_map; end
+
       # @return [::Array<String>]
       def gates
         # @todo This check might not be necessary. There should always be a
diff --git a/lib/solargraph/pin/common.rb b/lib/solargraph/pin/common.rb
index 829dbe496..f7fbf4573 100644
--- a/lib/solargraph/pin/common.rb
+++ b/lib/solargraph/pin/common.rb
@@ -3,12 +3,22 @@
 module Solargraph
   module Pin
     module Common
+      # @!method closure
+      #   @abstract
+      #   @return [Pin::Closure, nil]
+      # @!method source
+      #   @abstract
+      #   @return [String, nil]
+
       # @return [Location]
       attr_reader :location
 
+      # @sg-ignore Solargraph::Pin::Common#closure return type could not be inferred
       # @return [Pin::Closure, nil]
       def closure
-        Solargraph.assert_or_log(:closure, "Closure not set on #{self.class} #{name.inspect} from #{source.inspect}") unless @closure
+        unless @closure
+          Solargraph.assert_or_log(:closure, "Closure not set on #{self.class} #{name.inspect} from #{source.inspect}")
+        end
         @closure
       end
 
diff --git a/lib/solargraph/pin/local_variable.rb b/lib/solargraph/pin/local_variable.rb
index c680bebd0..36b75773c 100644
--- a/lib/solargraph/pin/local_variable.rb
+++ b/lib/solargraph/pin/local_variable.rb
@@ -26,7 +26,7 @@ def combine_with(other, attrs={})
           assignment: assert_same(other, :assignment),
           presence_certain: assert_same(other, :presence_certain?),
         }.merge(attrs)
-        new_attrs[:presence] =  assert_same(other, :presence) unless attrs.key?(:presence)
+        new_attrs[:presence] = assert_same(other, :presence) unless attrs.key?(:presence)
 
         super(other, new_attrs)
       end
diff --git a/lib/solargraph/pin/method.rb b/lib/solargraph/pin/method.rb
index 6309cb55a..0a81d0c93 100644
--- a/lib/solargraph/pin/method.rb
+++ b/lib/solargraph/pin/method.rb
@@ -51,7 +51,7 @@ def combine_all_signature_pins(*signature_pins)
       end
 
       # @param other [Pin::Method]
-      # @return [Symbol]
+      # @return [::Symbol]
       def combine_visibility(other)
         if dodgy_visibility_source? && !other.dodgy_visibility_source?
           other.visibility
@@ -388,7 +388,7 @@ def probe api_map
         attribute? ? infer_from_iv(api_map) : infer_from_return_nodes(api_map)
       end
 
-      # @return [::Array<Pin::Method>]
+      # @return [::Array<Pin::Signature>]
       def overloads
         # Ignore overload tags with nil parameters. If it's not an array, the
         # tag's source is likely malformed.
diff --git a/lib/solargraph/pin/method_alias.rb b/lib/solargraph/pin/method_alias.rb
index 28be6d8b1..feb6baccc 100644
--- a/lib/solargraph/pin/method_alias.rb
+++ b/lib/solargraph/pin/method_alias.rb
@@ -26,6 +26,14 @@ def visibility
         :public
       end
 
+      def to_rbs
+        if scope == :class
+          "alias self.#{name} self.#{original}"
+        else
+          "alias #{name} #{original}"
+        end
+      end
+
       def path
         @path ||= namespace + (scope == :instance ? '#' : '.') + name
       end
diff --git a/lib/solargraph/pin/parameter.rb b/lib/solargraph/pin/parameter.rb
index e298ba20a..b4405de40 100644
--- a/lib/solargraph/pin/parameter.rb
+++ b/lib/solargraph/pin/parameter.rb
@@ -135,6 +135,11 @@ def full
                     end
       end
 
+      def reset_generated!
+        super
+        @return_type = nil if @return_type&.undefined?
+      end
+
       # @return [ComplexType]
       def return_type
         if @return_type.nil?
@@ -176,7 +181,13 @@ def compatible_arg?(atype, api_map)
         # make sure we get types from up the method
         # inheritance chain if we don't have them on this pin
         ptype = typify api_map
-        ptype.undefined? || ptype.can_assign?(api_map, atype) || ptype.generic?
+        return true if ptype.undefined?
+
+        return true if atype.conforms_to?(api_map,
+                                          ptype,
+                                          :method_call,
+                                          [:allow_empty_params, :allow_undefined])
+        ptype.generic?
       end
 
       def documentation
diff --git a/lib/solargraph/pin/proxy_type.rb b/lib/solargraph/pin/proxy_type.rb
index 819c97481..2323489a7 100644
--- a/lib/solargraph/pin/proxy_type.rb
+++ b/lib/solargraph/pin/proxy_type.rb
@@ -4,6 +4,7 @@ module Solargraph
   module Pin
     class ProxyType < Base
       # @param return_type [ComplexType]
+      # @param binder [ComplexType, ComplexType::UniqueType, nil]
       def initialize return_type: ComplexType::UNDEFINED, binder: nil, **splat
         super(**splat)
         @return_type = return_type
diff --git a/lib/solargraph/pin/reference/override.rb b/lib/solargraph/pin/reference/override.rb
index d547e3caf..878c309db 100644
--- a/lib/solargraph/pin/reference/override.rb
+++ b/lib/solargraph/pin/reference/override.rb
@@ -14,16 +14,30 @@ def closure
           nil
         end
 
+        # @param location [Location, nil]
+        # @param name [String]
+        # @param tags [::Array<YARD::Tags::Tag>]
+        # @param delete [::Array<Symbol>]
+        # @param splat [Hash]
         def initialize location, name, tags, delete = [], **splat
           super(location: location, name: name, **splat)
           @tags = tags
           @delete = delete
         end
 
+        # @param name [String]
+        # @param tags [::Array<String>]
+        # @param delete [::Array<Symbol>]
+        # @param splat [Hash]
+        # @return [Solargraph::Pin::Reference::Override]
         def self.method_return name, *tags, delete: [], **splat
-          new(nil, name, [YARD::Tags::Tag.new('return', nil, tags)], delete, **splat)
+          new(nil, name, [YARD::Tags::Tag.new('return', '', tags)], delete, **splat)
         end
 
+        # @param name [String]
+        # @param comment [String]
+        # @param splat [Hash]
+        # @return [Solargraph::Pin::Reference::Override]
         def self.from_comment name, comment, **splat
           new(nil, name, Solargraph::Source.parse_docstring(comment).to_docstring.tags, **splat)
         end
diff --git a/lib/solargraph/pin/search.rb b/lib/solargraph/pin/search.rb
index fc0f000cd..33f02e027 100644
--- a/lib/solargraph/pin/search.rb
+++ b/lib/solargraph/pin/search.rb
@@ -12,6 +12,8 @@ class Result
         # @return [Pin::Base]
         attr_reader :pin
 
+        # @param match [Float] The match score for the pin
+        # @param pin [Pin::Base]
         def initialize match, pin
           @match = match
           @pin = pin
diff --git a/lib/solargraph/pin/signature.rb b/lib/solargraph/pin/signature.rb
index 818d66411..4c25e028b 100644
--- a/lib/solargraph/pin/signature.rb
+++ b/lib/solargraph/pin/signature.rb
@@ -39,6 +39,8 @@ def typify api_map
         end
         return ComplexType::UNDEFINED if closure.nil?
         return ComplexType::UNDEFINED unless closure.is_a?(Pin::Method)
+        # @sg-ignore need is_a? support
+        # @type [Array<Pin::Method>]
         method_stack = closure.rest_of_stack api_map
         logger.debug { "Signature#typify(self=#{self}) - method_stack: #{method_stack}" }
         method_stack.each do |pin|
diff --git a/lib/solargraph/pin/symbol.rb b/lib/solargraph/pin/symbol.rb
index 9e11c3d7d..294363f5f 100644
--- a/lib/solargraph/pin/symbol.rb
+++ b/lib/solargraph/pin/symbol.rb
@@ -20,6 +20,10 @@ def path
         ''
       end
 
+      def closure
+        @closure ||= Pin::ROOT_PIN
+      end
+
       def completion_item_kind
         Solargraph::LanguageServer::CompletionItemKinds::KEYWORD
       end
@@ -36,6 +40,7 @@ def directives
         []
       end
 
+      # @return [::Symbol]
       def visibility
         :public
       end
diff --git a/lib/solargraph/pin_cache.rb b/lib/solargraph/pin_cache.rb
index 2a0ec4639..7e769b03b 100644
--- a/lib/solargraph/pin_cache.rb
+++ b/lib/solargraph/pin_cache.rb
@@ -1,12 +1,429 @@
-require 'yard-activesupport-concern'
 require 'fileutils'
 require 'rbs'
+require 'rubygems'
 
 module Solargraph
-  module PinCache
+  class PinCache
+    include Logging
+
+    attr_reader :directory, :rbs_collection_path, :rbs_collection_config_path, :yard_plugins
+
+    # @param rbs_collection_path [String, nil]
+    # @param rbs_collection_config_path [String, nil]
+    # @param directory [String, nil]
+    # @param yard_plugins [Array<String>]
+    def initialize rbs_collection_path:, rbs_collection_config_path:,
+                   directory:,
+                   yard_plugins:
+      @rbs_collection_path = rbs_collection_path
+      @rbs_collection_config_path = rbs_collection_config_path
+      @directory = directory
+      @yard_plugins = yard_plugins
+    end
+
+    # @param gemspec [Gem::Specification, Bundler::LazySpecification]
+    def cached? gemspec
+      rbs_version_cache_key = lookup_rbs_version_cache_key(gemspec)
+      combined_gem?(gemspec, rbs_version_cache_key)
+    end
+
+    # @param gemspec [Gem::Specification, Bundler::LazySpecification]
+    # @param rebuild [Boolean] whether to rebuild the cache regardless of whether it already exists
+    # @param out [IO, nil] output stream for logging
+    # @return [void]
+    def cache_gem gemspec:, rebuild: false, out: nil
+      rbs_version_cache_key = lookup_rbs_version_cache_key(gemspec)
+
+      build_yard, build_rbs_collection, build_combined =
+        calculate_build_needs(gemspec,
+                              rebuild: rebuild,
+                              rbs_version_cache_key: rbs_version_cache_key)
+
+      return unless build_yard || build_rbs_collection || build_combined
+
+      build_combine_and_cache(gemspec,
+                              rbs_version_cache_key,
+                              build_yard: build_yard,
+                              build_rbs_collection: build_rbs_collection,
+                              build_combined: build_combined,
+                              out: out)
+    end
+
+    # @param gemspec [Gem::Specification, Bundler::LazySpecification]
+    # @param rbs_version_cache_key [String]
+    def suppress_yard_cache? gemspec, rbs_version_cache_key
+      if gemspec.name == 'parser' && rbs_version_cache_key != RbsMap::CACHE_KEY_UNRESOLVED
+        # parser takes forever to build YARD pins, but has excellent RBS collection pins
+        return true
+      end
+      false
+    end
+
+    # @param out [IO, nil] output stream for logging
+    #
+    # @return [void]
+    def cache_all_stdlibs out: $stderr
+      possible_stdlibs.each do |stdlib|
+        RbsMap::StdlibMap.new(stdlib, out: out)
+      end
+    end
+
+    # @param path [String] require path that might be in the RBS stdlib collection
+    # @return [void]
+    def cache_stdlib_rbs_map path
+      # these are held in memory in RbsMap::StdlibMap
+      map = RbsMap::StdlibMap.load(path)
+      if map.resolved?
+        logger.debug { "Loading stdlib pins for #{path}" }
+        pins = map.pins
+        logger.debug { "Loaded #{pins.length} stdlib pins for #{path}" }
+        pins
+      else
+        # @todo Temporarily ignoring unresolved `require 'set'`
+        logger.debug { "Require path #{path} could not be resolved in RBS" } unless path == 'set'
+        nil
+      end
+    end
+
+    # @param gemspec [Gem::Specification, Bundler::LazySpecification]
+    #
+    # @return [String]
+    def lookup_rbs_version_cache_key gemspec
+      rbs_map = RbsMap.from_gemspec(gemspec, rbs_collection_path, rbs_collection_config_path)
+      rbs_map.cache_key
+    end
+
+    # @param gemspec [Gem::Specification]
+    # @param rbs_version_cache_key [String]
+    # @param yard_pins [Array<Pin::Base>]
+    # @param rbs_collection_pins [Array<Pin::Base>]
+    # @return [void]
+    def cache_combined_pins gemspec, rbs_version_cache_key, yard_pins, rbs_collection_pins
+      combined_pins = GemPins.combine(yard_pins, rbs_collection_pins)
+      serialize_combined_gem(gemspec, rbs_version_cache_key, combined_pins)
+    end
+
+    # @param gemspec [Gem::Specification]
+    # @return [Array<Pin::Base>]
+    def deserialize_combined_pin_cache gemspec
+      rbs_version_cache_key = lookup_rbs_version_cache_key(gemspec)
+
+      load_combined_gem(gemspec, rbs_version_cache_key)
+    end
+
+    # @param gemspec [Gem::Specification]
+    # @param out [IO, nil]
+    # @return [void]
+    def uncache_gem gemspec, out: nil
+      PinCache.uncache(yardoc_path(gemspec), out: out)
+      PinCache.uncache(yard_gem_path(gemspec), out: out)
+      uncache_by_prefix(rbs_collection_pins_path_prefix(gemspec), out: out)
+      uncache_by_prefix(combined_path_prefix(gemspec), out: out)
+      combined_pins_in_memory.delete([gemspec.name, gemspec.version])
+    end
+
+    # @param gemspec [Gem::Specification, Bundler::LazySpecification]
+    def yardoc_processing? gemspec
+      Yardoc.processing?(yardoc_path(gemspec))
+    end
+
+    # @return [Array<String>] a list of possible standard library names
+    def possible_stdlibs
+      # all dirs and .rb files in Gem::RUBYGEMS_DIR
+      Dir.glob(File.join(Gem::RUBYGEMS_DIR, '*')).map do |file_or_dir|
+        basename = File.basename(file_or_dir)
+        # remove .rb
+        basename = basename[0..-4] if basename.end_with?('.rb')
+        basename
+      end.sort.uniq
+    rescue StandardError => e
+      logger.info { "Failed to get possible stdlibs: #{e.message}" }
+      logger.debug { e.backtrace.join("\n") }
+      []
+    end
+
+    private
+
+    # @param gemspec [Gem::Specification, Bundler::LazySpecification]
+    # @param rebuild [Boolean] whether to rebuild the cache regardless of whether it already exists
+    # @param rbs_version_cache_key [String, nil] the cache key for the gem in the RBS collection
+    #
+    # @return [Array(Boolean, Boolean, Boolean)] whether to build YARD
+    #   pins, RBS collection pins, and combined pins
+    def calculate_build_needs gemspec, rebuild:, rbs_version_cache_key:
+      if rebuild
+        build_yard = true
+        build_rbs_collection = true
+        build_combined = true
+      else
+        build_yard = !yard_gem?(gemspec)
+        build_rbs_collection = !rbs_collection_pins?(gemspec, rbs_version_cache_key)
+        build_combined = !combined_gem?(gemspec, rbs_version_cache_key) || build_yard || build_rbs_collection
+      end
+
+      build_yard = false if suppress_yard_cache?(gemspec, rbs_version_cache_key)
+
+      [build_yard, build_rbs_collection, build_combined]
+    end
+
+    # @param gemspec [Gem::Specification, Bundler::LazySpecification]
+    # @param rbs_version_cache_key [String, nil]
+    # @param build_yard [Boolean]
+    # @param build_rbs_collection [Boolean]
+    # @param build_combined [Boolean]
+    # @param out [IO, nil]
+    #
+    # @return [void]
+    def build_combine_and_cache gemspec,
+                                rbs_version_cache_key,
+                                build_yard:,
+                                build_rbs_collection:,
+                                build_combined:,
+                                out:
+      log_cache_info(gemspec, rbs_version_cache_key,
+                     build_yard: build_yard,
+                     build_rbs_collection: build_rbs_collection,
+                     build_combined: build_combined,
+                     out: out)
+      cache_yard_pins(gemspec, out) if build_yard
+      # this can be nil even if we aren't told to build it - see suppress_yard_cache?
+      yard_pins = deserialize_yard_pin_cache(gemspec) || []
+      cache_rbs_collection_pins(gemspec, out) if build_rbs_collection
+      rbs_collection_pins = deserialize_rbs_collection_cache(gemspec, rbs_version_cache_key) || []
+      cache_combined_pins(gemspec, rbs_version_cache_key, yard_pins, rbs_collection_pins) if build_combined
+    end
+
+    # @param gemspec [Gem::Specification, Bundler::LazySpecification]
+    # @param rbs_version_cache_key [String, nil]
+    # @param build_yard [Boolean]
+    # @param build_rbs_collection [Boolean]
+    # @param build_combined [Boolean]
+    # @param out [IO, nil]
+    #
+    # @return [void]
+    def log_cache_info gemspec,
+                       rbs_version_cache_key,
+                       build_yard:,
+                       build_rbs_collection:,
+                       build_combined:,
+                       out:
+      type = []
+      type << 'YARD' if build_yard
+      rbs_source_desc = RbsMap.rbs_source_desc(rbs_version_cache_key)
+      type << rbs_source_desc if build_rbs_collection && !rbs_source_desc.nil?
+      # we'll build it anyway, but it won't take long to build with
+      # only a single source
+
+      # 'combining' is awkward terminology in this case
+      just_yard = build_yard && rbs_source_desc.nil?
+
+      type << 'combined' if build_combined && !just_yard
+      out&.puts("Caching #{type.join(' and ')} pins for gem #{gemspec.name}:#{gemspec.version}")
+    end
+
+    # @param gemspec [Gem::Specification, Bundler::LazySpecification]
+    # @param out [IO, nil]
+    # @return [Array<Pin::Base>]
+    def cache_yard_pins gemspec, out
+      gem_yardoc_path = yardoc_path(gemspec)
+      Yardoc.build_docs(gem_yardoc_path, yard_plugins, gemspec) unless Yardoc.docs_built?(gem_yardoc_path)
+      pins = Yardoc.build_pins(gem_yardoc_path, gemspec, out: out)
+      serialize_yard_gem(gemspec, pins)
+      logger.info { "Cached #{pins.length} YARD pins for gem #{gemspec.name}:#{gemspec.version}" } unless pins.empty?
+      pins
+    end
+
+    # @return [Hash{Array(String, String, String) => Array<Pin::Base>}]
+    def combined_pins_in_memory
+      PinCache.all_combined_pins_in_memory[yard_plugins] ||= {}
+    end
+
+    # @param gemspec [Gem::Specification]
+    # @param _out [IO, nil]
+    # @return [Array<Pin::Base>]
+    def cache_rbs_collection_pins gemspec, _out
+      rbs_map = RbsMap.from_gemspec(gemspec, rbs_collection_path, rbs_collection_config_path)
+      pins = rbs_map.pins
+      rbs_version_cache_key = rbs_map.cache_key
+      # cache pins even if result is zero, so we don't retry building pins
+      pins ||= []
+      serialize_rbs_collection_pins(gemspec, rbs_version_cache_key, pins)
+      logger.info do
+        unless pins.empty?
+          "Cached #{pins.length} RBS collection pins for gem #{gemspec.name} #{gemspec.version} with " \
+            "cache_key #{rbs_version_cache_key.inspect}"
+        end
+      end
+      pins
+    end
+
+    # @param gemspec [Gem::Specification]
+    # @return [Array<Pin::Base>]
+    def deserialize_yard_pin_cache gemspec
+      cached = load_yard_gem(gemspec)
+      if cached
+        cached
+      else
+        logger.debug "No YARD pin cache for #{gemspec.name}:#{gemspec.version}"
+        nil
+      end
+    end
+
+    # @param gemspec [Gem::Specification, Bundler::LazySpecification]
+    # @param rbs_version_cache_key [String]
+    # @return [Array<Pin::Base>]
+    def deserialize_rbs_collection_cache gemspec, rbs_version_cache_key
+      cached = load_rbs_collection_pins(gemspec, rbs_version_cache_key)
+      Solargraph.assert_or_log(:pin_cache_rbs_collection, 'Asked for non-existent rbs collection') if cached.nil?
+      logger.info do
+        "Loaded #{cached&.length} pins from RBS collection cache for #{gemspec.name}:#{gemspec.version}"
+      end
+      cached
+    end
+
+    # @return [Array<String>]
+    def yard_path_components
+      ["yard-#{YARD::VERSION}",
+       yard_plugins.sort.uniq.join('-')]
+    end
+
+    # @param gemspec [Gem::Specification]
+    # @return [String]
+    def yardoc_path gemspec
+      File.join(PinCache.base_dir,
+                *yard_path_components,
+                "#{gemspec.name}-#{gemspec.version}.yardoc")
+    end
+
+    # @param gemspec [Gem::Specification]
+    # @return [String]
+    def yard_gem_path gemspec
+      File.join(PinCache.work_dir, *yard_path_components, "#{gemspec.name}-#{gemspec.version}.ser")
+    end
+
+    # @param gemspec [Gem::Specification]
+    # @return [Array<Pin::Base>, nil]
+    def load_yard_gem gemspec
+      PinCache.load(yard_gem_path(gemspec))
+    end
+
+    # @param gemspec [Gem::Specification]
+    # @param pins [Array<Pin::Base>]
+    # @return [void]
+    def serialize_yard_gem gemspec, pins
+      PinCache.save(yard_gem_path(gemspec), pins)
+    end
+
+    # @param gemspec [Gem::Specification]
+    # @return [Boolean]
+    def yard_gem? gemspec
+      exist?(yard_gem_path(gemspec))
+    end
+
+    # @param gemspec [Gem::Specification]
+    # @param hash [String, nil]
+    # @return [String]
+    def rbs_collection_pins_path gemspec, hash
+      rbs_collection_pins_path_prefix(gemspec) + "#{hash || 0}.ser"
+    end
+
+    # @param gemspec [Gem::Specification]
+    # @return [String]
+    def rbs_collection_pins_path_prefix gemspec
+      File.join(PinCache.work_dir, 'rbs', "#{gemspec.name}-#{gemspec.version}-")
+    end
+
+    # @param gemspec [Gem::Specification, Bundler::LazySpecification]
+    # @param hash [String]
+    #
+    # @return [Array<Pin::Base>, nil]
+    def load_rbs_collection_pins gemspec, hash
+      PinCache.load(rbs_collection_pins_path(gemspec, hash))
+    end
+
+    # @param gemspec [Gem::Specification]
+    # @param hash [String, nil]
+    # @param pins [Array<Pin::Base>]
+    # @return [void]
+    def serialize_rbs_collection_pins gemspec, hash, pins
+      PinCache.save(rbs_collection_pins_path(gemspec, hash), pins)
+    end
+
+    # @param gemspec [Gem::Specification]
+    # @param hash [String, nil]
+    # @return [String]
+    def combined_path gemspec, hash
+      File.join(combined_path_prefix(gemspec) + "-#{hash || 0}.ser")
+    end
+
+    # @param gemspec [Gem::Specification]
+    # @return [String]
+    def combined_path_prefix gemspec
+      File.join(PinCache.work_dir, 'combined', yard_plugins.sort.join('-'), "#{gemspec.name}-#{gemspec.version}")
+    end
+
+    # @param gemspec [Gem::Specification]
+    # @param hash [String, nil]
+    # @param pins [Array<Pin::Base>]
+    # @return [void]
+    def serialize_combined_gem gemspec, hash, pins
+      PinCache.save(combined_path(gemspec, hash), pins)
+    end
+
+    # @param gemspec [Gem::Specification, Bundler::LazySpecification]
+    # @param hash [String]
+    def combined_gem? gemspec, hash
+      exist?(combined_path(gemspec, hash))
+    end
+
+    # @param gemspec [Gem::Specification]
+    # @param hash [String, nil]
+    # @return [Array<Pin::Base>, nil]
+    def load_combined_gem gemspec, hash
+      PinCache.load(combined_path(gemspec, hash))
+    end
+
+    # @param gemspec [Gem::Specification]
+    # @param hash [String]
+    def rbs_collection_pins? gemspec, hash
+      exist?(rbs_collection_pins_path(gemspec, hash))
+    end
+
+    include Logging
+
+    # @param path [String]
+    def exist? *path
+      File.file? File.join(*path)
+    end
+
+    # @return [void]
+    # @param path_segments [Array<String>]
+    def uncache_by_prefix *path_segments, out: nil
+      path = File.join(*path_segments)
+      glob = "#{path}*"
+      out&.puts "Clearing pin cache in #{glob}"
+      Dir.glob(glob).each do |file|
+        next unless File.file?(file)
+        FileUtils.rm_rf file, secure: true
+        out&.puts "Clearing pin cache in #{file}"
+      end
+    end
+
     class << self
       include Logging
 
+      # @param path [String]
+      def exist? *path
+        File.file? File.join(*path)
+      end
+
+      # @return [Hash{Array<String> => Hash{Array(String, String) =>
+      #   Array<Pin::Base>}}] yard plugins, then gemspec name and
+      #   version
+      def all_combined_pins_in_memory
+        @all_combined_pins_in_memory ||= {}
+      end
+
       # The base directory where cached YARD documentation and serialized pins are serialized
       #
       # @return [String]
@@ -18,6 +435,32 @@ def base_dir
           File.join(Dir.home, '.cache', 'solargraph')
       end
 
+      # @param path_segments [Array<String>]
+      # @return [void]
+      def uncache *path_segments, out: nil
+        path = File.join(*path_segments)
+        if File.exist?(path)
+          FileUtils.rm_rf path, secure: true
+          out&.puts "Clearing pin cache in #{path}"
+        else
+          out&.puts "Pin cache file #{path} does not exist"
+        end
+      end
+
+      # @param out [IO, nil]
+      # @return [void]
+      def uncache_core out: nil
+        uncache(core_path, out: out)
+        # ApiMap keep this in memory
+        ApiMap.reset_core(out: out)
+      end
+
+      # @param out [IO, nil]
+      # @return [void]
+      def uncache_stdlib out: nil
+        uncache(stdlib_path, out: out)
+      end
+
       # The working directory for the current Ruby, RBS, and Solargraph versions.
       #
       # @return [String]
@@ -27,15 +470,6 @@ def work_dir
         File.join(base_dir, "ruby-#{RUBY_VERSION}", "rbs-#{RBS::VERSION}", "solargraph-#{Solargraph::VERSION}")
       end
 
-      # @param gemspec [Gem::Specification]
-      # @return [String]
-      def yardoc_path gemspec
-        File.join(base_dir,
-                  "yard-#{YARD::VERSION}",
-                  "yard-activesupport-concern-#{YARD::ActiveSupport::Concern::VERSION}",
-                  "#{gemspec.name}-#{gemspec.version}.yardoc")
-      end
-
       # @return [String]
       def stdlib_path
         File.join(work_dir, 'stdlib')
@@ -164,33 +598,11 @@ def has_rbs_collection?(gemspec, hash)
         exist?(rbs_collection_path(gemspec, hash))
       end
 
-      # @return [void]
-      def uncache_core
-        uncache(core_path)
-      end
-
-      # @return [void]
-      def uncache_stdlib
-        uncache(stdlib_path)
-      end
-
-      # @param gemspec [Gem::Specification]
-      # @param out [IO, nil]
-      # @return [void]
-      def uncache_gem(gemspec, out: nil)
-        uncache(yardoc_path(gemspec), out: out)
-        uncache_by_prefix(rbs_collection_path_prefix(gemspec), out: out)
-        uncache(yard_gem_path(gemspec), out: out)
-        uncache_by_prefix(combined_path_prefix(gemspec), out: out)
-      end
-
       # @return [void]
       def clear
         FileUtils.rm_rf base_dir, secure: true
       end
 
-      private
-
       # @param file [String]
       # @return [Array<Solargraph::Pin::Base>, nil]
       def load file
@@ -202,11 +614,6 @@ def load file
         nil
       end
 
-      # @param path [String]
-      def exist? *path
-        File.file? File.join(*path)
-      end
-
       # @param file [String]
       # @param pins [Array<Pin::Base>]
       # @return [void]
@@ -218,27 +625,14 @@ def save file, pins
         logger.debug { "Cache#save: Saved #{pins.length} pins to #{file}" }
       end
 
-      # @param path_segments [Array<String>]
-      # @return [void]
-      def uncache *path_segments, out: nil
-        path = File.join(*path_segments)
-        if File.exist?(path)
-          FileUtils.rm_rf path, secure: true
-          out.puts "Clearing pin cache in #{path}" unless out.nil?
-        end
+      def core?
+        File.file?(core_path)
       end
 
-      # @return [void]
-      # @param path_segments [Array<String>]
-      def uncache_by_prefix *path_segments, out: nil
-        path = File.join(*path_segments)
-        glob = "#{path}*"
-        out.puts "Clearing pin cache in #{glob}" unless out.nil?
-        Dir.glob(glob).each do |file|
-          next unless File.file?(file)
-          FileUtils.rm_rf file, secure: true
-          out.puts "Clearing pin cache in #{file}" unless out.nil?
-        end
+      # @param out [IO, nil]
+      # @return [Array<Pin::Base>]
+      def cache_core out: $stderr
+        RbsMap::CoreMap.new.cache_core(out: out)
       end
     end
   end
diff --git a/lib/solargraph/position.rb b/lib/solargraph/position.rb
index 1bd31e0f5..ec8605d18 100644
--- a/lib/solargraph/position.rb
+++ b/lib/solargraph/position.rb
@@ -21,11 +21,11 @@ def initialize line, character
       @character = character
     end
 
-    # @sg-ignore Fix "Not enough arguments to Module#protected"
     protected def equality_fields
       [line, character]
     end
 
+    # @param other [Position]
     def <=>(other)
       return nil unless other.is_a?(Position)
       if line == other.line
diff --git a/lib/solargraph/range.rb b/lib/solargraph/range.rb
index 615f180af..2bea62797 100644
--- a/lib/solargraph/range.rb
+++ b/lib/solargraph/range.rb
@@ -19,11 +19,11 @@ def initialize start, ending
       @ending = ending
     end
 
-    # @sg-ignore Fix "Not enough arguments to Module#protected"
     protected def equality_fields
       [start, ending]
     end
 
+    # @param other [Object]
     def <=>(other)
       return nil unless other.is_a?(Range)
       if start == other.start
@@ -78,7 +78,7 @@ def self.from_to l1, c1, l2, c2
 
     # Get a range from a node.
     #
-    # @param node [Parser::AST::Node]
+    # @param node [AST::Node]
     # @return [Range, nil]
     def self.from_node node
       if node&.loc && node.loc.expression
diff --git a/lib/solargraph/rbs_map.rb b/lib/solargraph/rbs_map.rb
index 2f36ce991..1dad9e4a8 100644
--- a/lib/solargraph/rbs_map.rb
+++ b/lib/solargraph/rbs_map.rb
@@ -23,10 +23,11 @@ class RbsMap
     attr_reader :rbs_collection_config_path
 
     # @param library [String]
-    # @param version [String, nil
+    # @param version [String, nil]
     # @param rbs_collection_config_path [String, Pathname, nil]
     # @param rbs_collection_paths [Array<Pathname, String>]
-    def initialize library, version = nil, rbs_collection_config_path: nil, rbs_collection_paths: []
+    # @param out [IO, nil] where to log messages
+    def initialize library, version = nil, rbs_collection_config_path: nil, rbs_collection_paths: [], out: $stderr
       if rbs_collection_config_path.nil? && !rbs_collection_paths.empty?
         raise 'Please provide rbs_collection_config_path if you provide rbs_collection_paths'
       end
@@ -37,19 +38,44 @@ def initialize library, version = nil, rbs_collection_config_path: nil, rbs_coll
       add_library loader, library, version
     end
 
+    CACHE_KEY_GEM_EXPORT = 'gem-export'
+    CACHE_KEY_UNRESOLVED = 'unresolved'
+    CACHE_KEY_STDLIB = 'stdlib'
+    CACHE_KEY_LOCAL = 'local'
+
+    # @param cache_key [String]
+    # @return [String, nil] a description of the source of the RBS info
+    def self.rbs_source_desc cache_key
+      case cache_key
+      when CACHE_KEY_GEM_EXPORT
+        'RBS gem export'
+      when CACHE_KEY_UNRESOLVED
+        nil
+      when CACHE_KEY_STDLIB
+        'RBS standard library'
+      when CACHE_KEY_LOCAL
+        'local RBS shims'
+      else
+        'RBS collection'
+      end
+    end
+
     # @return [RBS::EnvironmentLoader]
     def loader
       @loader ||= RBS::EnvironmentLoader.new(core_root: nil, repository: repository)
     end
 
-    # @sg-ignore
     # @return [String] representing the version of the RBS info fetched
     #   for the given library.  Must change when the RBS info is
     #   updated upstream for the same library and version.  May change
     #   if the config for where information comes form changes.
     def cache_key
+      return CACHE_KEY_UNRESOLVED unless resolved?
+
       @hextdigest ||= begin
         data = nil
+        # @type gem_config [nil, Hash{String => Hash{String => String}}]
+        gem_config = nil
         if rbs_collection_config_path
           lockfile_path = RBS::Collection::Config.to_lockfile_path(Pathname.new(rbs_collection_config_path))
           if lockfile_path.exist?
@@ -58,21 +84,26 @@ def cache_key
             data = gem_config&.to_s
           end
         end
-        if data.nil? || data.empty?
-          if resolved?
-            # definitely came from the gem itself and not elsewhere -
-            # only one version per gem
-            'gem-export'
+        if gem_config.nil?
+          CACHE_KEY_STDLIB
+        else
+          # @type [String]
+          source = gem_config.dig('source', 'type')
+          case source
+          when 'rubygems'
+            CACHE_KEY_GEM_EXPORT
+          when 'local'
+            CACHE_KEY_LOCAL
+          when 'stdlib'
+            CACHE_KEY_STDLIB
           else
-            'unresolved'
+            Digest::SHA1.hexdigest(data)
           end
-        else
-          Digest::SHA1.hexdigest(data)
         end
       end
     end
 
-    # @param gemspec [Gem::Specification]
+    # @param gemspec [Gem::Specification, Bundler::LazySpecification]
     # @param rbs_collection_path [String, Pathname, nil]
     # @param rbs_collection_config_path [String, Pathname, nil]
     # @return [RbsMap]
@@ -83,14 +114,24 @@ def self.from_gemspec gemspec, rbs_collection_path, rbs_collection_config_path
       return rbs_map if rbs_map.resolved?
 
       # try any version of the gem in the collection
-      RbsMap.new(gemspec.name, nil,
-                 rbs_collection_paths: [rbs_collection_path].compact,
-                 rbs_collection_config_path: rbs_collection_config_path)
+      rbs_map = RbsMap.new(gemspec.name, nil,
+                           rbs_collection_paths: [rbs_collection_path].compact,
+                           rbs_collection_config_path: rbs_collection_config_path)
+
+      return rbs_map if rbs_map.resolved?
+
+      StdlibMap.new(gemspec.name)
     end
 
+    # @param out [IO, nil] where to log messages
     # @return [Array<Pin::Base>]
-    def pins
-      @pins ||= resolved? ? conversions.pins : []
+    def pins out: $stderr
+      @pins ||= if resolved?
+                  loader.libs.each { |lib| log_caching(lib, out: out) }
+                  conversions.pins
+                else
+                  []
+                end
     end
 
     # @generic T
@@ -140,15 +181,22 @@ def conversions
       @conversions ||= Conversions.new(loader: loader)
     end
 
+    # @param lib [RBS::EnvironmentLoader::Library]
+    # @param out [IO, nil] where to log messages
+    # @return [void]
+    def log_caching lib, out:; end
+
     # @param loader [RBS::EnvironmentLoader]
     # @param library [String]
-    # @param version [String, nil]
+    # @param version [String, nil] the version of the library to load, or nil for any
+    # @param out [IO, nil] where to log messages
     # @return [Boolean] true if adding the library succeeded
-    def add_library loader, library, version
+    def add_library loader, library, version, out: $stderr
       @resolved = if loader.has_library?(library: library, version: version)
-        loader.add library: library, version: version
-        logger.debug { "#{short_name} successfully loaded library #{library}:#{version}" }
-        true
+                    # we find our own dependencies from gemfile.lock
+                    loader.add library: library, version: version, resolve_dependencies: false
+                    logger.debug { "#{short_name} successfully loaded library #{library}:#{version}" }
+                    true
       else
         logger.info { "#{short_name} did not find data for library #{library}:#{version}" }
         false
diff --git a/lib/solargraph/rbs_map/conversions.rb b/lib/solargraph/rbs_map/conversions.rb
index 6e50c022a..851ce7560 100644
--- a/lib/solargraph/rbs_map/conversions.rb
+++ b/lib/solargraph/rbs_map/conversions.rb
@@ -95,7 +95,7 @@ def convert_self_type_to_pins decl, closure
         type = build_type(decl.name, decl.args)
         generic_values = type.all_params.map(&:to_s)
         include_pin = Solargraph::Pin::Reference::Include.new(
-          name: decl.name.relative!.to_s,
+          name: type.rooted_name,
           type_location: location_decl_to_pin_location(decl.location),
           generic_values: generic_values,
           closure: closure,
@@ -184,7 +184,7 @@ def class_decl_to_pin decl
             type_location: location_decl_to_pin_location(decl.super_class.location),
             closure: class_pin,
             generic_values: generic_values,
-            name: decl.super_class.name.relative!.to_s,
+            name: type.rooted_name,
             source: :rbs
           )
         end
@@ -229,6 +229,8 @@ def module_decl_to_pin decl
         convert_self_types_to_pins decl, module_pin
         convert_members_to_pins decl, module_pin
 
+        raise "Invalid type for module declaration: #{module_pin.class}" unless module_pin.is_a?(Pin::Namespace)
+
         add_mixins decl, module_pin.closure
       end
 
@@ -240,6 +242,7 @@ def module_decl_to_pin decl
       #
       # @return [Solargraph::Pin::Constant]
       def create_constant(name, tag, comments, decl, base = nil)
+        tag = "#{base}<#{tag}>" if base
         parts = name.split('::')
         if parts.length > 1
           name = parts.last
@@ -255,7 +258,6 @@ def create_constant(name, tag, comments, decl, base = nil)
           comments: comments,
           source: :rbs
         )
-        tag = "#{base}<#{tag}>" if base
         rooted_tag = ComplexType.parse(tag).force_rooted.rooted_tags
         constant_pin.docstring.add_tag(YARD::Tags::Tag.new(:return, '', rooted_tag))
         constant_pin
@@ -345,7 +347,7 @@ def global_decl_to_pin decl
       }
 
       # @param decl [RBS::AST::Members::MethodDefinition, RBS::AST::Members::AttrReader, RBS::AST::Members::AttrAccessor]
-      # @param closure [Pin::Namespace]
+      # @param closure [Pin::Closure]
       # @param context [Context]
       # @param scope [Symbol] :instance or :class
       # @param name [String] The name of the method
@@ -476,7 +478,15 @@ def parts_of_function type, pin
         end
         if type.type.rest_positionals
           name = type.type.rest_positionals.name ? type.type.rest_positionals.name.to_s : "arg_#{arg_num += 1}"
-          parameters.push Solargraph::Pin::Parameter.new(decl: :restarg, name: name, closure: pin, source: :rbs, type_location: type_location)
+          inner_rest_positional_type =
+            ComplexType.try_parse(other_type_to_tag(type.type.rest_positionals.type))
+          rest_positional_type = ComplexType::UniqueType.new('Array',
+                                                             [],
+                                                             [inner_rest_positional_type],
+                                                             rooted: true, parameters_type: :list)
+          parameters.push Solargraph::Pin::Parameter.new(decl: :restarg, name: name, closure: pin,
+                                                         source: :rbs, type_location: type_location,
+                                                         return_type: rest_positional_type,)
         end
         type.type.trailing_positionals.each do |param|
           name = param.name ? param.name.to_s : "arg_#{arg_num += 1}"
@@ -699,13 +709,13 @@ def method_type_to_tag type
       # @return [ComplexType::UniqueType]
       def build_type(type_name, type_args = [])
         base = RBS_TO_YARD_TYPE[type_name.relative!.to_s] || type_name.relative!.to_s
-        params = type_args.map { |a| other_type_to_tag(a) }.reject { |t| t == 'undefined' }.map do |t|
+        params = type_args.map { |a| other_type_to_tag(a) }.map do |t|
           ComplexType.try_parse(t).force_rooted
         end
         if base == 'Hash' && params.length == 2
           ComplexType::UniqueType.new(base, [params.first], [params.last], rooted: true, parameters_type: :hash)
         else
-          ComplexType::UniqueType.new(base, [], params, rooted: true, parameters_type: :list)
+          ComplexType::UniqueType.new(base, [], params.reject(&:undefined?), rooted: true, parameters_type: :list)
         end
       end
 
diff --git a/lib/solargraph/rbs_map/core_map.rb b/lib/solargraph/rbs_map/core_map.rb
index 0d265d773..cb530cbec 100644
--- a/lib/solargraph/rbs_map/core_map.rb
+++ b/lib/solargraph/rbs_map/core_map.rb
@@ -5,44 +5,59 @@ class RbsMap
     # Ruby core pins
     #
     class CoreMap
+      include Logging
 
       def resolved?
         true
       end
 
-      FILLS_DIRECTORY = File.join(File.dirname(__FILE__), '..', '..', '..', 'rbs', 'fills')
+      FILLS_DIRECTORY = File.expand_path(File.join(File.dirname(__FILE__), '..', '..', '..', 'rbs', 'fills'))
 
       def initialize; end
 
-      def pins
+      # @param out [IO, nil] output stream for logging
+      # @return [Array<Pin::Base>]
+      def pins out: $stderr
         return @pins if @pins
+        @pins = cache_core(out: out)
+      end
 
-        @pins = []
+      # @param out [IO, nil] output stream for logging
+      # @return [Array<Pin::Base>]
+      def cache_core out: $stderr
+        new_pins = []
         cache = PinCache.deserialize_core
-        if cache
-          @pins.replace cache
-        else
-          loader.add(path: Pathname(FILLS_DIRECTORY))
-          @pins = conversions.pins
-          @pins.concat RbsMap::CoreFills::ALL
-          processed = ApiMap::Store.new(pins).pins.reject { |p| p.is_a?(Solargraph::Pin::Reference::Override) }
-          @pins.replace processed
-
-          PinCache.serialize_core @pins
-        end
-        @pins
-      end
+        return cache if cache
 
-      def loader
-        @loader ||= RBS::EnvironmentLoader.new(repository: RBS::Repository.new(no_stdlib: false))
+        new_pins.concat conversions.pins
+
+        # Avoid RBS::DuplicatedDeclarationError by loading in a different EnvironmentLoader
+        fill_loader = RBS::EnvironmentLoader.new(core_root: nil, repository: RBS::Repository.new(no_stdlib: false))
+        fill_loader.add(path: Pathname(FILLS_DIRECTORY))
+        out&.puts 'Caching RBS pins for Ruby core'
+        fill_conversions = Conversions.new(loader: fill_loader)
+        new_pins.concat fill_conversions.pins
+
+        # add some overrides
+        new_pins.concat RbsMap::CoreFills::ALL
+
+        # process overrides, then remove any which couldn't be resolved
+        processed = ApiMap::Store.new(new_pins).pins.reject { |p| p.is_a?(Solargraph::Pin::Reference::Override) }
+        new_pins.replace processed
+
+        PinCache.serialize_core new_pins
+
+        new_pins
       end
 
       private
 
+      # @return [RBS::EnvironmentLoader]
       def loader
         @loader ||= RBS::EnvironmentLoader.new(repository: RBS::Repository.new(no_stdlib: false))
       end
 
+      # @return [Conversions]
       def conversions
         @conversions ||= Conversions.new(loader: loader)
       end
diff --git a/lib/solargraph/rbs_map/stdlib_map.rb b/lib/solargraph/rbs_map/stdlib_map.rb
index b6804157f..e7891bfe3 100644
--- a/lib/solargraph/rbs_map/stdlib_map.rb
+++ b/lib/solargraph/rbs_map/stdlib_map.rb
@@ -12,8 +12,13 @@ class StdlibMap < RbsMap
       # @type [Hash{String => RbsMap}]
       @stdlib_maps_hash = {}
 
+      def log_caching lib, out: $stderr
+        out&.puts("Caching RBS pins for standard library #{lib.name}")
+      end
+
       # @param library [String]
-      def initialize library
+      # @param out [IO, nil] where to log messages
+      def initialize library, out: $stderr
         cached_pins = PinCache.deserialize_stdlib_require library
         if cached_pins
           @pins = cached_pins
@@ -24,7 +29,7 @@ def initialize library
           super
           unless resolved?
             @pins = []
-            logger.info { "Could not resolve #{library.inspect}" }
+            logger.debug { "StdlibMap could not resolve #{library.inspect}" }
             return
           end
           generated_pins = pins
@@ -33,6 +38,22 @@ def initialize library
         end
       end
 
+      # @return [RBS::Collection::Sources::Stdlib]
+      def self.source
+        @source ||= RBS::Collection::Sources::Stdlib.instance
+      end
+
+      # @param name [String]
+      # @param version [String, nil]
+      # @return [Array<Hash{String => String}>, nil]
+      def self.stdlib_dependencies name, version = nil
+        if source.has?(name, version)
+          source.dependencies_of(name, version)
+        else
+          []
+        end
+      end
+
       # @param library [String]
       # @return [StdlibMap]
       def self.load library
diff --git a/lib/solargraph/shell.rb b/lib/solargraph/shell.rb
index afea86a92..2111c1821 100755
--- a/lib/solargraph/shell.rb
+++ b/lib/solargraph/shell.rb
@@ -3,10 +3,14 @@
 require 'benchmark'
 require 'thor'
 require 'yard'
+require 'sord'
+require 'tmpdir'
+require 'yaml'
 
 module Solargraph
   class Shell < Thor
     include Solargraph::ServerMethods
+    include ApiMap::SourceToYard
 
     # Tell Thor to ensure the process exits with status 1 if any error happens.
     def self.exit_on_failure?
@@ -15,7 +19,7 @@ def self.exit_on_failure?
 
     map %w[--version -v] => :version
 
-    desc "--version, -v", "Print the version"
+    desc '--version, -v', 'Print the version'
     # @return [void]
     def version
       puts Solargraph::VERSION
@@ -36,6 +40,7 @@ def socket
         Signal.trap("TERM") do
           Backport.stop
         end
+        # @sg-ignore https://github.com/castwide/backport/pull/5
         Backport.prepare_tcp_server host: options[:host], port: port, adapter: Solargraph::LanguageServer::Transport::Adapter
         STDERR.puts "Solargraph is listening PORT=#{port} PID=#{Process.pid}"
       end
@@ -52,6 +57,7 @@ def stdio
         Signal.trap("TERM") do
           Backport.stop
         end
+        # @sg-ignore https://github.com/castwide/backport/pull/5
         Backport.prepare_stdio_server adapter: Solargraph::LanguageServer::Transport::Adapter
         STDERR.puts "Solargraph is listening on stdio PID=#{Process.pid}"
       end
@@ -101,12 +107,63 @@ def clear
     # @param gem [String]
     # @param version [String, nil]
     def cache gem, version = nil
-      api_map = Solargraph::ApiMap.load(Dir.pwd)
-      spec = Gem::Specification.find_by_name(gem, version)
-      api_map.cache_gem(spec, rebuild: options[:rebuild], out: $stdout)
+      gems(gem + (version ? "=#{version}" : ''))
+      # '
     end
 
-    desc 'uncache GEM [...GEM]', "Delete specific cached gem documentation"
+    desc 'gems [GEM[=VERSION]...] [STDLIB...] [core]', 'Cache documentation for
+         installed libraries'
+    long_desc %( This command will cache the
+    generated type documentation for the specified libraries.  While
+    Solargraph will generate this on the fly when needed, it takes
+    time.  This command will generate it in advance, which can be
+    useful for CI scenarios.
+
+        With no arguments, it will cache all libraries in the current
+        workspace.  If a gem or standard library name is specified, it
+        will cache that library's type documentation.
+
+        An equals sign after a gem will allow a specific gem version
+        to be cached.
+
+        The 'core' argument can be used to cache the type
+        documentation for the core Ruby libraries.
+
+        If the library is already cached, it will be rebuilt if the
+        --rebuild option is set.
+
+        Cached documentation is stored in #{PinCache.base_dir}, which
+        can be stored between CI runs.
+    )
+    option :rebuild, type: :boolean, desc: 'Rebuild existing documentation', default: false
+    # @param names [Array<String>]
+    # @return [void]
+    def gems *names
+      # print time with ms
+      workspace = Solargraph::Workspace.new('.')
+
+      if names.empty?
+        workspace.cache_all_for_workspace!($stdout, rebuild: options[:rebuild])
+      else
+        $stderr.puts("Caching these gems: #{names}")
+        names.each do |name|
+          if name == 'core'
+            PinCache.cache_core(out: $stdout)
+            next
+          end
+
+          gemspec = workspace.find_gem(*name.split('='))
+          if gemspec.nil?
+            warn "Gem '#{name}' not found"
+          else
+            workspace.cache_gem(gemspec, rebuild: options[:rebuild], out: $stdout)
+          end
+        end
+        $stderr.puts "Documentation cached for #{names.count} gems."
+      end
+    end
+
+    desc 'uncache GEM [...GEM]', 'Delete specific cached gem documentation'
     long_desc %(
       Specify one or more gem names to clear. 'core' or 'stdlib' may
       also be specified to clear cached system documentation.
@@ -116,39 +173,20 @@ def cache gem, version = nil
     # @return [void]
     def uncache *gems
       raise ArgumentError, 'No gems specified.' if gems.empty?
+      workspace = Workspace.new('.')
       gems.each do |gem|
         if gem == 'core'
-          PinCache.uncache_core
+          PinCache.uncache_core(out: $stdout)
           next
         end
 
         if gem == 'stdlib'
-          PinCache.uncache_stdlib
+          PinCache.uncache_stdlib(out: $stdout)
           next
         end
 
         spec = Gem::Specification.find_by_name(gem)
-        PinCache.uncache_gem(spec, out: $stdout)
-      end
-    end
-
-    desc 'gems [GEM[=VERSION]]', 'Cache documentation for installed gems'
-    option :rebuild, type: :boolean, desc: 'Rebuild existing documentation', default: false
-    # @param names [Array<String>]
-    # @return [void]
-    def gems *names
-      api_map = ApiMap.load('.')
-      if names.empty?
-        Gem::Specification.to_a.each { |spec| do_cache spec, api_map }
-        STDERR.puts "Documentation cached for all #{Gem::Specification.count} gems."
-      else
-        names.each do |name|
-          spec = Gem::Specification.find_by_name(*name.split('='))
-          do_cache spec, api_map
-        rescue Gem::MissingSpecError
-          warn "Gem '#{name}' not found"
-        end
-        STDERR.puts "Documentation cached for #{names.count} gems."
+        workspace.uncache_gem(spec, out: $stdout)
       end
     end
 
@@ -189,7 +227,6 @@ def typecheck *files
           filecount += 1
           probcount += problems.length
         end
-        # "
       }
       puts "Typecheck finished in #{time.real} seconds."
       puts "#{probcount} problem#{probcount != 1 ? 's' : ''} found#{files.length != 1 ? " in #{filecount} of #{files.length} files" : ''}."
@@ -212,7 +249,7 @@ def scan
       # @type [Solargraph::ApiMap, nil]
       api_map = nil
       time = Benchmark.measure {
-        api_map = Solargraph::ApiMap.load_with_cache(directory, $stdout)
+        api_map = Solargraph::ApiMap.load_with_cache(directory, out: $stdout)
         api_map.pins.each do |pin|
           begin
             puts pin_description(pin) if options[:verbose]
@@ -239,6 +276,77 @@ def list
       puts "#{workspace.filenames.length} files total."
     end
 
+    desc 'rbs', 'Generate RBS definitions'
+    option :filename, type: :string, alias: :f, desc: 'Generated file name', default: 'sig.rbs'
+    option :inference, type: :boolean, desc: 'Enhance definitions with type inference', default: true
+    # @return [void]
+    def rbs
+      api_map = Solargraph::ApiMap.load('.')
+      pins = api_map.source_maps.flat_map(&:pins)
+      store = Solargraph::ApiMap::Store.new(pins)
+      if options[:inference]
+        store.method_pins.each do |pin|
+          next unless pin.return_type.undefined?
+
+          type = pin.typify(api_map)
+          type = pin.probe(api_map) if type.undefined?
+          pin.docstring.add_tag YARD::Tags::Tag.new('return', '', type.items.map(&:to_s))
+          pin.instance_variable_set(:@return_type, type)
+        end
+      end
+      rake_yard(store)
+      work_dir = Dir.pwd
+      Dir.mktmpdir do |tmpdir|
+        Dir.chdir tmpdir do
+          yardoc = File.join(tmpdir, '.yardoc')
+          YARD::Registry.save(false, yardoc)
+          YARD::Registry.load(yardoc)
+          target = File.join(work_dir, 'sig', options[:filename])
+          FileUtils.mkdir_p(File.join(work_dir, 'sig'))
+          `sord #{target} --rbs --no-regenerate`
+        end
+      end
+    end
+
+    desc 'method_pin [PATH]', 'Describe a method pin'
+    option :rbs, type: :boolean, desc: 'Output the pin as RBS', default: false
+    option :typify, type: :boolean, desc: 'Output the calculated return type of the pin from annotations', default: false
+    option :probe, type: :boolean, desc: 'Output the calculated return type of the pin from annotations and inference', default: false
+    option :stack, type: :boolean, desc: 'Show entire stack by including definitions in superclasses', default: false
+    # @param path [String] The path to the method pin, e.g. 'Class#method' or 'Class.method'
+    # @return [void]
+    def method_pin path
+      api_map = Solargraph::ApiMap.load_with_cache('.', out: $stderr)
+
+      # @type [Array<Pin::Base>]
+      pins = if options[:stack]
+               scope, ns, meth = if path.include? '#'
+                                   [:instance, *path.split('#', 2)]
+                                 else
+                                   [:class, *path.split('.', 2)]
+                                 end
+               # @sg-ignore need better splat destructuring support
+               api_map.get_method_stack(ns, meth, scope: scope)
+             else
+               api_map.get_path_pins path
+             end
+      if pins.empty?
+        $stderr.puts "Pin not found for path '#{path}'"
+        exit 1
+      end
+      pins.each do |pin|
+        if options[:typify] || options[:probe]
+          type = ComplexType::UNDEFINED
+          type = pin.typify(api_map) if options[:typify]
+          type = pin.probe(api_map) if options[:probe] && type.undefined?
+          print_type(type)
+          next
+        end
+
+        print_pin(pin)
+      end
+    end
+
     private
 
     # @param pin [Solargraph::Pin::Base]
@@ -257,13 +365,24 @@ def pin_description pin
       desc
     end
 
-    # @param gemspec [Gem::Specification]
-    # @param api_map [ApiMap]
+    # @param type [ComplexType]
+    # @return [void]
+    def print_type(type)
+      if options[:rbs]
+        puts type.to_rbs
+      else
+        puts type.rooted_tag
+      end
+    end
+
+    # @param pin [Solargraph::Pin::Base]
     # @return [void]
-    def do_cache gemspec, api_map
-      # @todo if the rebuild: option is passed as a positional arg,
-      #   typecheck doesn't complain on the below line
-      api_map.cache_gem(gemspec, rebuild: options.rebuild, out: $stdout)
+    def print_pin(pin)
+      if options[:rbs]
+        puts pin.to_rbs
+      else
+        puts pin.inspect
+      end
     end
   end
 end
diff --git a/lib/solargraph/source.rb b/lib/solargraph/source.rb
index d2b24cc61..0af8b0cdf 100644
--- a/lib/solargraph/source.rb
+++ b/lib/solargraph/source.rb
@@ -187,7 +187,7 @@ def code_for(node)
       frag.strip.gsub(/,$/, '')
     end
 
-    # @param node [Parser::AST::Node]
+    # @param node [AST::Node]
     # @return [String, nil]
     def comments_for node
       rng = Range.from_node(node)
@@ -318,7 +318,7 @@ def string_nodes
       @string_nodes ||= string_nodes_in(node)
     end
 
-    # @return [Array<Range>]
+    # @return [Array<Solargraph::Range>]
     def comment_ranges
       @comment_ranges ||= comments.values.map(&:range)
     end
@@ -387,6 +387,7 @@ def changes
     # @return [Integer]
     attr_writer :version
 
+    # @return [void]
     def finalize
       return if @finalized && changes.empty?
 
@@ -441,6 +442,7 @@ def code=(val)
     # @return [String]
     attr_writer :repaired
 
+    # @return [String]
     def repaired
       finalize
       @repaired
diff --git a/lib/solargraph/source/chain.rb b/lib/solargraph/source/chain.rb
index 065c3bf10..5850364a4 100644
--- a/lib/solargraph/source/chain.rb
+++ b/lib/solargraph/source/chain.rb
@@ -17,6 +17,10 @@ class Chain
       include Equality
       include Logging
 
+      #
+      # A chain of constants, variables, and method calls for inferring types of
+      # values.
+      #
       autoload :Link,             'solargraph/source/chain/link'
       autoload :Call,             'solargraph/source/chain/call'
       autoload :QCall,            'solargraph/source/chain/q_call'
@@ -269,7 +273,10 @@ def infer_from_definitions pins, context, api_map, locals
                else
                  ComplexType.new(types)
                end
-        return type if context.nil? || context.return_type.undefined?
+        if context.nil? || context.return_type.undefined?
+          # up to downstream to resolve self type
+          return type
+        end
 
         type.self_to_type(context.return_type)
       end
diff --git a/lib/solargraph/source/chain/if.rb b/lib/solargraph/source/chain/if.rb
index c14d00ddf..3a7fa0ca9 100644
--- a/lib/solargraph/source/chain/if.rb
+++ b/lib/solargraph/source/chain/if.rb
@@ -8,7 +8,7 @@ def word
           '<if>'
         end
 
-        # @param links [::Array<Link>]
+        # @param links [::Array<Chain>]
         def initialize links
           @links = links
         end
diff --git a/lib/solargraph/source/chain/or.rb b/lib/solargraph/source/chain/or.rb
index 1e3a70f40..9264d4107 100644
--- a/lib/solargraph/source/chain/or.rb
+++ b/lib/solargraph/source/chain/or.rb
@@ -8,7 +8,7 @@ def word
           '<or>'
         end
 
-        # @param links [::Array<Link>]
+        # @param links [::Array<Chain>]
         def initialize links
           @links = links
         end
diff --git a/lib/solargraph/source_map.rb b/lib/solargraph/source_map.rb
index 84b3a4bcc..1fea14870 100644
--- a/lib/solargraph/source_map.rb
+++ b/lib/solargraph/source_map.rb
@@ -32,11 +32,13 @@ def initialize source
 
       environ.merge Convention.for_local(self) unless filename.nil?
       self.convention_pins = environ.pins
+      # @type [Hash{Class<generic<T>> => Array<generic<T>>}]
       @pin_select_cache = {}
     end
 
-    # @param klass [Class]
-    # @return [Array<Pin::Base>]
+    # @generic T
+    # @param klass [Class<generic<T>>]
+    # @return [Array<generic<T>>]
     def pins_by_class klass
       @pin_select_cache[klass] ||= pin_class_hash.select { |key, _| key <= klass }.values.flatten
     end
@@ -114,10 +116,13 @@ def locate_named_path_pin line, character
     # @param line [Integer]
     # @param character [Integer]
     # @return [Pin::Namespace,Pin::Method,Pin::Block]
-    def locate_block_pin line, character
-      _locate_pin line, character, Pin::Namespace, Pin::Method, Pin::Block
+    def locate_closure_pin line, character
+      _locate_pin line, character, Pin::Closure
     end
 
+    # @deprecated Please use locate_closure_pin instead
+    alias locate_block_pin locate_closure_pin
+
     # @param name [String]
     # @return [Array<Location>]
     def references name
@@ -158,10 +163,12 @@ def map source
 
     private
 
+    # @return [Hash{Class => Array<Pin::Base>}]
     def pin_class_hash
       @pin_class_hash ||= pins.to_set.classify(&:class).transform_values(&:to_a)
     end
 
+    # @return [Data]
     def data
       @data ||= Data.new(source)
     end
diff --git a/lib/solargraph/source_map/clip.rb b/lib/solargraph/source_map/clip.rb
index ba69b1b93..3d198ac1e 100644
--- a/lib/solargraph/source_map/clip.rb
+++ b/lib/solargraph/source_map/clip.rb
@@ -11,15 +11,14 @@ class Clip
       def initialize api_map, cursor
         @api_map = api_map
         @cursor = cursor
-        block_pin = block
-        block_pin.rebind(api_map) if block_pin.is_a?(Pin::Block) && !Solargraph::Range.from_node(block_pin.receiver).contain?(cursor.range.start)
-        @in_block = nil
+        closure_pin = closure
+        closure_pin.rebind(api_map) if closure_pin.is_a?(Pin::Block) && !Solargraph::Range.from_node(closure_pin.receiver).contain?(cursor.range.start)
       end
 
       # @return [Array<Pin::Base>] Relevant pins for infering the type of the Cursor's position
       def define
         return [] if cursor.comment? || cursor.chain.literal?
-        result = cursor.chain.define(api_map, block, locals)
+        result = cursor.chain.define(api_map, closure, locals)
         result.concat file_global_methods
         result.concat((source_map.pins + source_map.locals).select{ |p| p.name == cursor.word && p.location.range.contain?(cursor.position) }) if result.empty?
         result
@@ -51,43 +50,36 @@ def signify
 
       # @return [ComplexType]
       def infer
-        result = cursor.chain.infer(api_map, block, locals)
+        result = cursor.chain.infer(api_map, closure, locals)
         if result.tag == 'Class'
           # HACK: Exception to return BasicObject from Class#new
-          dfn = cursor.chain.define(api_map, block, locals).first
+          dfn = cursor.chain.define(api_map, closure, locals).first
           return ComplexType.try_parse('::BasicObject') if dfn && dfn.path == 'Class#new'
         end
-        return result unless result.tag == 'self'
-        cursor.chain.base.infer(api_map, block, locals)
+        # should receive result with selfs resolved from infer()
+        Solargraph.assert_or_log(:clip_infer_self, 'Received selfy inference') if result.selfy?
+        result
       end
 
       # Get an array of all the locals that are visible from the cursors's
       # position. Locals can be local variables, method parameters, or block
       # parameters. The array starts with the nearest local pin.
       #
-      # @return [::Array<Solargraph::Pin::Base>]
+      # @return [::Array<Solargraph::Pin::LocalVariable>]
       def locals
         @locals ||= source_map.locals_at(location)
       end
 
       # @return [::Array<String>]
       def gates
-        block.gates
-      end
-
-      def in_block?
-        return @in_block unless @in_block.nil?
-        @in_block = begin
-          tree = cursor.source.tree_at(cursor.position.line, cursor.position.column)
-          Parser.is_ast_node?(tree[1]) && [:block, :ITER].include?(tree[1].type)
-        end
+        closure.gates
       end
 
       # @param phrase [String]
       # @return [Array<Solargraph::Pin::Base>]
       def translate phrase
         chain = Parser.chain(Parser.parse(phrase))
-        chain.define(api_map, block, locals)
+        chain.define(api_map, closure, locals)
       end
 
       private
@@ -109,8 +101,8 @@ def location
       end
 
       # @return [Solargraph::Pin::Closure]
-      def block
-        @block ||= source_map.locate_block_pin(cursor.node_position.line, cursor.node_position.character)
+      def closure
+        @closure ||= source_map.locate_closure_pin(cursor.node_position.line, cursor.node_position.character)
       end
 
       # The context at the current position.
@@ -201,20 +193,20 @@ def code_complete
             result.concat api_map.get_constants(type.namespace, cursor.start_of_constant? ? '' : context_pin.full_context.namespace, *gates)
           end
         else
-          type = cursor.chain.base.infer(api_map, block, locals)
-          result.concat api_map.get_complex_type_methods(type, block.binder.namespace, cursor.chain.links.length == 1)
+          type = cursor.chain.base.infer(api_map, closure, locals)
+          result.concat api_map.get_complex_type_methods(type, closure.binder.namespace, cursor.chain.links.length == 1)
           if cursor.chain.links.length == 1
             if cursor.word.start_with?('@@')
               return package_completions(api_map.get_class_variable_pins(context_pin.full_context.namespace))
             elsif cursor.word.start_with?('@')
-              return package_completions(api_map.get_instance_variable_pins(block.binder.namespace, block.binder.scope))
+              return package_completions(api_map.get_instance_variable_pins(closure.binder.namespace, closure.binder.scope))
             elsif cursor.word.start_with?('$')
               return package_completions(api_map.get_global_variable_pins)
             end
             result.concat locals
-            result.concat file_global_methods unless block.binder.namespace.empty?
+            result.concat file_global_methods unless closure.binder.namespace.empty?
             result.concat api_map.get_constants(context_pin.context.namespace, *gates)
-            result.concat api_map.get_methods(block.binder.namespace, scope: block.binder.scope, visibility: [:public, :private, :protected])
+            result.concat api_map.get_methods(closure.binder.namespace, scope: closure.binder.scope, visibility: [:public, :private, :protected])
             result.concat api_map.get_methods('Kernel')
             result.concat api_map.keyword_pins.to_a
           end
diff --git a/lib/solargraph/source_map/data.rb b/lib/solargraph/source_map/data.rb
index 9d1b30bac..453520414 100644
--- a/lib/solargraph/source_map/data.rb
+++ b/lib/solargraph/source_map/data.rb
@@ -3,15 +3,18 @@
 module Solargraph
   class SourceMap
     class Data
+      # @param source [Solargraph::Source]
       def initialize source
         @source = source
       end
 
+      # @return [Array<Solargraph::Pin::Base>]
       def pins
         generate
         @pins || []
       end
 
+      # @return [Array<Solargraph::LocalVariable>]
       def locals
         generate
         @locals || []
@@ -19,6 +22,7 @@ def locals
 
       private
 
+      # @return [void]
       def generate
         return if @generated
 
diff --git a/lib/solargraph/type_checker.rb b/lib/solargraph/type_checker.rb
index e99f99195..7c3a74829 100644
--- a/lib/solargraph/type_checker.rb
+++ b/lib/solargraph/type_checker.rb
@@ -5,11 +5,8 @@ module Solargraph
   #
   class TypeChecker
     autoload :Problem,  'solargraph/type_checker/problem'
-    autoload :ParamDef, 'solargraph/type_checker/param_def'
     autoload :Rules,    'solargraph/type_checker/rules'
-    autoload :Checks,   'solargraph/type_checker/checks'
 
-    include Checks
     include Parser::NodeMethods
 
     # @return [String]
@@ -43,6 +40,39 @@ def source
       @source_map.source
     end
 
+    # @param inferred [ComplexType]
+    # @param expected [ComplexType]
+    def return_type_conforms_to?(inferred, expected)
+      conforms_to?(inferred, expected, :return_type)
+    end
+
+    # @param inferred [ComplexType]
+    # @param expected [ComplexType]
+    def arg_conforms_to?(inferred, expected)
+      conforms_to?(inferred, expected, :method_call)
+    end
+
+    # @param inferred [ComplexType]
+    # @param expected [ComplexType]
+    def assignment_conforms_to?(inferred, expected)
+      conforms_to?(inferred, expected, :assignment)
+    end
+
+    # @param inferred [ComplexType]
+    # @param expected [ComplexType]
+    # @param scenario [Symbol]
+    def conforms_to?(inferred, expected, scenario)
+      rules_arr = []
+      rules_arr << :allow_empty_params unless rules.require_inferred_type_params?
+      rules_arr << :allow_any_match unless rules.require_all_unique_types_match_declared?
+      rules_arr << :allow_undefined unless rules.require_no_undefined_args?
+      rules_arr << :allow_unresolved_generic unless rules.require_generics_resolved?
+      rules_arr << :allow_unmatched_interface unless rules.require_interfaces_resolved?
+      rules_arr << :allow_reverse_match unless rules.require_downcasts?
+      inferred.conforms_to?(api_map, expected, scenario,
+                            rules_arr)
+    end
+
     # @return [Array<Problem>]
     def problems
       @problems ||= begin
@@ -69,10 +99,10 @@ def load filename, level = :normal
       # @param code [String]
       # @param filename [String, nil]
       # @param level [Symbol]
+      # @param api_map [Solargraph::ApiMap]
       # @return [self]
-      def load_string code, filename = nil, level = :normal
+      def load_string code, filename = nil, level = :normal, api_map: Solargraph::ApiMap.new
         source = Solargraph::Source.load_string(code, filename)
-        api_map = Solargraph::ApiMap.new
         api_map.map(source)
         new(filename, api_map: api_map, level: level)
       end
@@ -118,7 +148,7 @@ def method_return_type_problems_for pin
               result.push Problem.new(pin.location, "#{pin.path} return type could not be inferred", pin: pin)
             end
           else
-            unless (rules.require_all_return_types_match_inferred? ? all_types_match?(api_map, inferred, declared) : any_types_match?(api_map, declared, inferred))
+            unless return_type_conforms_to?(inferred, declared)
               result.push Problem.new(pin.location, "Declared return type #{declared.rooted_tags} does not match inferred type #{inferred.rooted_tags} for #{pin.path}", pin: pin)
             end
           end
@@ -152,33 +182,33 @@ def virtual_pin? pin
     # @return [Array<Problem>]
     def method_param_type_problems_for pin
       stack = api_map.get_method_stack(pin.namespace, pin.name, scope: pin.scope)
-      params = first_param_hash(stack)
       result = []
-      if rules.require_type_tags?
-        pin.signatures.each do |sig|
-          sig.parameters.each do |par|
-            break if par.decl == :restarg || par.decl == :kwrestarg || par.decl == :blockarg
-            unless params[par.name]
-              if pin.attribute?
-                inferred = pin.probe(api_map).self_to_type(pin.full_context)
-                if inferred.undefined?
+      pin.signatures.each do |sig|
+        params = param_details_from_stack(sig, stack)
+        if rules.require_type_tags?
+            sig.parameters.each do |par|
+              break if par.decl == :restarg || par.decl == :kwrestarg || par.decl == :blockarg
+              unless params[par.name]
+                if pin.attribute?
+                  inferred = pin.probe(api_map).self_to_type(pin.full_context)
+                  if inferred.undefined?
+                    result.push Problem.new(pin.location, "Missing @param tag for #{par.name} on #{pin.path}", pin: pin)
+                  end
+                else
                   result.push Problem.new(pin.location, "Missing @param tag for #{par.name} on #{pin.path}", pin: pin)
                 end
-              else
-                result.push Problem.new(pin.location, "Missing @param tag for #{par.name} on #{pin.path}", pin: pin)
               end
             end
-          end
         end
-      end
-      # @todo Should be able to probe type of name and data here
-      # @param name [String]
-      # @param data [Hash{Symbol => BasicObject}]
-      params.each_pair do |name, data|
-        # @type [ComplexType]
-        type = data[:qualified]
-        if type.undefined?
-          result.push Problem.new(pin.location, "Unresolved type #{data[:tagged]} for #{name} param on #{pin.path}", pin: pin)
+        # @todo Should be able to probe type of name and data here
+        # @param name [String]
+        # @param data [Hash{Symbol => BasicObject}]
+        params.each_pair do |name, data|
+          # @type [ComplexType]
+          type = data[:qualified]
+          if type.undefined?
+            result.push Problem.new(pin.location, "Unresolved type #{data[:tagged]} for #{name} param on #{pin.path}", pin: pin)
+          end
         end
       end
       result
@@ -207,7 +237,7 @@ def variable_type_tag_problems
                   result.push Problem.new(pin.location, "Variable type could not be inferred for #{pin.name}", pin: pin)
                 end
               else
-                unless any_types_match?(api_map, declared, inferred)
+                unless assignment_conforms_to?(inferred, declared)
                   result.push Problem.new(pin.location, "Declared type #{declared} does not match inferred type #{inferred} for variable #{pin.name}", pin: pin)
                 end
               end
@@ -239,10 +269,11 @@ def const_problems
       Solargraph::Parser::NodeMethods.const_nodes_from(source.node).each do |const|
         rng = Solargraph::Range.from_node(const)
         chain = Solargraph::Parser.chain(const, filename)
-        block_pin = source_map.locate_block_pin(rng.start.line, rng.start.column)
+        closure_pin = source_map.locate_closure_pin(rng.start.line, rng.start.column)
+        closure_pin.rebind(api_map)
         location = Location.new(filename, rng)
         locals = source_map.locals_at(location)
-        pins = chain.define(api_map, block_pin, locals)
+        pins = chain.define(api_map, closure_pin, locals)
         if pins.empty?
           result.push Problem.new(location, "Unresolved constant #{Solargraph::Parser::NodeMethods.unpack_name(const)}")
           @marked_ranges.push location.range
@@ -258,17 +289,25 @@ def call_problems
         rng = Solargraph::Range.from_node(call)
         next if @marked_ranges.any? { |d| d.contain?(rng.start) }
         chain = Solargraph::Parser.chain(call, filename)
-        block_pin = source_map.locate_block_pin(rng.start.line, rng.start.column)
+        closure_pin = source_map.locate_closure_pin(rng.start.line, rng.start.column)
+        namespace_pin = closure_pin
+        if call.type == :block
+          # blocks in the AST include the method call as well, so the
+          # node returned by #call_nodes_from needs to be backed out
+          # one closure
+          closure_pin = closure_pin.closure
+        end
+        closure_pin.rebind(api_map)
         location = Location.new(filename, rng)
         locals = source_map.locals_at(location)
-        type = chain.infer(api_map, block_pin, locals)
+        type = chain.infer(api_map, closure_pin, locals)
         if type.undefined? && !rules.ignore_all_undefined?
           base = chain
           missing = chain
           found = nil
           closest = ComplexType::UNDEFINED
           until base.links.first.undefined?
-            found = base.define(api_map, block_pin, locals).first
+            found = base.define(api_map, closure_pin, locals).first
             break if found
             missing = base
             base = base.base
@@ -282,140 +321,150 @@ def call_problems
             end
           end
         end
-        result.concat argument_problems_for(chain, api_map, block_pin, locals, location)
+        result.concat argument_problems_for(chain, api_map, closure_pin, locals, location)
       end
       result
     end
 
     # @param chain [Solargraph::Source::Chain]
     # @param api_map [Solargraph::ApiMap]
-    # @param block_pin [Solargraph::Pin::Base]
-    # @param locals [Array<Solargraph::Pin::Base>]
+    # @param closure_pin [Solargraph::Pin::Closure]
+    # @param locals [Array<Solargraph::Pin::LocalVariable>]
     # @param location [Solargraph::Location]
     # @return [Array<Problem>]
-    def argument_problems_for chain, api_map, block_pin, locals, location
+    def argument_problems_for chain, api_map, closure_pin, locals, location
       result = []
       base = chain
-      until base.links.length == 1 && base.undefined?
-        last_base_link = base.links.last
-        break unless last_base_link.is_a?(Solargraph::Source::Chain::Call)
-
-        arguments = last_base_link.arguments
-
-        pins = base.define(api_map, block_pin, locals)
-
-        first_pin = pins.first
-        if first_pin.is_a?(Pin::DelegatedMethod) && !first_pin.resolvable?(api_map)
-          # Do nothing, as we can't find the actual method implementation
-        elsif first_pin.is_a?(Pin::Method)
-          # @type [Pin::Method]
-          pin = first_pin
-          ap = if base.links.last.is_a?(Solargraph::Source::Chain::ZSuper)
-            arity_problems_for(pin, fake_args_for(block_pin), location)
-          elsif pin.path == 'Class#new'
-            fqns = if base.links.one?
-              block_pin.namespace
+      # @type last_base_link [Solargraph::Source::Chain::Call]
+      last_base_link = base.links.last
+      return [] unless last_base_link.is_a?(Solargraph::Source::Chain::Call)
+
+      arguments = last_base_link.arguments
+
+      pins = base.define(api_map, closure_pin, locals)
+
+      first_pin = pins.first
+      unresolvable = first_pin.is_a?(Pin::DelegatedMethod) && !first_pin.resolvable?(api_map)
+      if !unresolvable && first_pin.is_a?(Pin::Method)
+        # @type [Pin::Method]
+        pin = first_pin
+        ap = if base.links.last.is_a?(Solargraph::Source::Chain::ZSuper)
+               arity_problems_for(pin, fake_args_for(closure_pin), location)
+             elsif pin.path == 'Class#new'
+               fqns = if base.links.one?
+                        closure_pin.namespace
+                      else
+                        base.base.infer(api_map, closure_pin, locals).namespace
+                      end
+               init = api_map.get_method_stack(fqns, 'initialize').first
+
+               init ? arity_problems_for(init, arguments, location) : []
+             else
+               arity_problems_for(pin, arguments, location)
+             end
+        return ap unless ap.empty?
+        return [] if !rules.validate_calls? || base.links.first.is_a?(Solargraph::Source::Chain::ZSuper)
+
+        all_errors = []
+        pin.signatures.sort { |sig| sig.parameters.length }.each do |sig|
+          signature_errors = signature_argument_problems_for location, locals, closure_pin, arguments, sig, pin, pins
+          if signature_errors.empty?
+            # we found a signature that works - meaning errors from
+            # other signatures don't matter.
+            return []
+          end
+          all_errors.concat signature_errors
+        end
+        result.concat all_errors
+      end
+      result
+    end
+
+    # @param location [Location]
+    # @param locals [Array<Pin::LocalVariable>]
+    # @param closure_pin [Pin::Closure]
+    # @param arguments [Array<Source::Chain>]
+    # @param sig [Pin::Signature]
+    # @param pin [Pin::Method]
+    # @param pins [Array<Pin::Method>]
+    #
+    # @return [Array<Problem>]
+    def signature_argument_problems_for location, locals, closure_pin, arguments, sig, pin, pins
+      params = param_details_from_stack(sig, pins)
+
+      errors = []
+      # @todo add logic mapping up restarg parameters with
+      #   arguments (including restarg arguments).  Use tuples
+      #   when possible, and when not, ensure provably
+      #   incorrect situations are detected.
+      sig.parameters.each_with_index do |par, idx|
+        return errors if par.decl == :restarg  # bail out and assume the rest is valid pending better arg processing
+        argchain = arguments[idx]
+        if argchain.nil?
+          if par.decl == :arg
+            final_arg = arguments.last
+            if final_arg && final_arg.node.type == :splat
+              argchain = final_arg
+              return errors
             else
-              base.base.infer(api_map, block_pin, locals).namespace
+              errors.push Problem.new(location, "Not enough arguments to #{pin.path}")
             end
-            init = api_map.get_method_stack(fqns, 'initialize').first
-            init ? arity_problems_for(init, arguments, location) : []
           else
-            arity_problems_for(pin, arguments, location)
+            final_arg = arguments.last
+            argchain = final_arg if final_arg && [:kwsplat, :hash].include?(final_arg.node.type)
           end
-          unless ap.empty?
-            result.concat ap
-            break
-          end
-          break if !rules.validate_calls? || base.links.first.is_a?(Solargraph::Source::Chain::ZSuper)
-
-          params = first_param_hash(pins)
-
-          all_errors = []
-          pin.signatures.sort { |sig| sig.parameters.length }.each do |sig|
-            errors = []
-            sig.parameters.each_with_index do |par, idx|
-              # @todo add logic mapping up restarg parameters with
-              #   arguments (including restarg arguments).  Use tuples
-              #   when possible, and when not, ensure provably
-              #   incorrect situations are detected.
-              break if par.decl == :restarg  # bail out pending better arg processing
-              argchain = arguments[idx]
-              if argchain.nil?
-                if par.decl == :arg
-                  final_arg = arguments.last
-                  if final_arg && final_arg.node.type == :splat
-                    argchain = final_arg
-                    next # don't try to apply the type of the splat - unlikely to be specific enough
-                  else
-                    errors.push Problem.new(location, "Not enough arguments to #{pin.path}")
-                    next
-                  end
-                else
-                  final_arg = arguments.last
-                  argchain = final_arg if final_arg && [:kwsplat, :hash].include?(final_arg.node.type)
-                end
-              end
-              if argchain
-                if par.decl != :arg
-                  errors.concat kwarg_problems_for sig, argchain, api_map, block_pin, locals, location, pin, params, idx
-                  next
-                else
-                  if argchain.node.type == :splat && argchain == arguments.last
-                    final_arg = argchain
-                  end
-                  if (final_arg && final_arg.node.type == :splat)
-                    # The final argument given has been seen and was a
-                    # splat, which doesn't give us useful types or
-                    # arities against positional parameters, so let's
-                    # continue on in case there are any required
-                    # kwargs we should warn about
-                    next
-                  end
-
-                  if argchain.node.type == :splat && par != sig.parameters.last
-                    # we have been given a splat and there are more
-                    # arguments to come.
+        end
+        if argchain
+          if par.decl != :arg
+            errors.concat kwarg_problems_for sig, argchain, api_map, closure_pin, locals, location, pin, params, idx
+            next
+          else
+            if argchain.node.type == :splat && argchain == arguments.last
+              final_arg = argchain
+            end
+            if (final_arg && final_arg.node.type == :splat)
+              # The final argument given has been seen and was a
+              # splat, which doesn't give us useful types or
+              # arities against positional parameters, so let's
+              # continue on in case there are any required
+              # kwargs we should warn about
+              next
+            end
+            if argchain.node.type == :splat && par != sig.parameters.last
+              # we have been given a splat and there are more
+              # arguments to come.
+
+              # @todo Improve this so that we can skip past the
+              #   rest of the positional parameters here but still
+              #   process the kwargs
+              return errors
+            end
+            ptype = params.key?(par.name) ? params[par.name][:qualified] : ComplexType::UNDEFINED
+            ptype = ptype.self_to_type(par.context)
+            if ptype.nil?
+            # @todo Some level (strong, I guess) should require the param here
+            else
+              argtype = argchain.infer(api_map, closure_pin, locals)
+              argtype = argtype.self_to_type(closure_pin.context)
 
-                    # @todo Improve this so that we can skip past the
-                    #   rest of the positional parameters here but still
-                    #   process the kwargs
-                    break
-                  end
-                  ptype = params.key?(par.name) ? params[par.name][:qualified] : ComplexType::UNDEFINED
-                  ptype = ptype.self_to_type(par.context)
-                  if ptype.nil?
-                    # @todo Some level (strong, I guess) should require the param here
-                  else
-                    argtype = argchain.infer(api_map, block_pin, locals)
-                    if argtype.defined? && ptype.defined? && !any_types_match?(api_map, ptype, argtype)
-                      errors.push Problem.new(location, "Wrong argument type for #{pin.path}: #{par.name} expected #{ptype}, received #{argtype}")
-                      next
-                    end
-                  end
-                end
-              elsif par.decl == :kwarg
-                errors.push Problem.new(location, "Call to #{pin.path} is missing keyword argument #{par.name}")
-                next
+              if argtype.defined? && ptype.defined? && !arg_conforms_to?(argtype, ptype)
+                errors.push Problem.new(location, "Wrong argument type for #{pin.path}: #{par.name} expected #{ptype}, received #{argtype}")
+                return errors
               end
             end
-            if errors.empty?
-              all_errors.clear
-              break
-            end
-            all_errors.concat errors
           end
-          result.concat all_errors
+        elsif par.decl == :kwarg
+          errors.push Problem.new(location, "Call to #{pin.path} is missing keyword argument #{par.name}")
+          next
         end
-        base = base.base
       end
-      result
+      errors
     end
 
     # @param sig [Pin::Signature]
     # @param argchain [Source::Chain]
     # @param api_map [ApiMap]
-    # @param block_pin [Pin::Block]
+    # @param closure_pin [Pin::Closure]
     # @param locals [Array<Pin::LocalVariable>]
     # @param location [Location]
     # @param pin [Pin::Method]
@@ -423,13 +472,13 @@ def argument_problems_for chain, api_map, block_pin, locals, location
     # @param idx [Integer]
     #
     # @return [Array<Problem>]
-    def kwarg_problems_for sig, argchain, api_map, block_pin, locals, location, pin, params, idx
+    def kwarg_problems_for sig, argchain, api_map, closure_pin, locals, location, pin, params, idx
       result = []
       kwargs = convert_hash(argchain.node)
       par = sig.parameters[idx]
       argchain = kwargs[par.name.to_sym]
       if par.decl == :kwrestarg || (par.decl == :optarg && idx == pin.parameters.length - 1 && par.asgn_code == '{}')
-        result.concat kwrestarg_problems_for(api_map, block_pin, locals, location, pin, params, kwargs)
+        result.concat kwrestarg_problems_for(api_map, closure_pin, locals, location, pin, params, kwargs)
       else
         if argchain
           data = params[par.name]
@@ -438,8 +487,10 @@ def kwarg_problems_for sig, argchain, api_map, block_pin, locals, location, pin,
           else
             ptype = data[:qualified]
             unless ptype.undefined?
-              argtype = argchain.infer(api_map, block_pin, locals)
-              if argtype.defined? && ptype && !any_types_match?(api_map, ptype, argtype)
+              argtype = argchain.infer(api_map, closure_pin, locals)
+              argtype = argtype.self_to_type(closure_pin.context)
+
+              if argtype.defined? && ptype && !arg_conforms_to?(argtype, ptype)
                 result.push Problem.new(location, "Wrong argument type for #{pin.path}: #{par.name} expected #{ptype}, received #{argtype}")
               end
             end
@@ -452,29 +503,48 @@ def kwarg_problems_for sig, argchain, api_map, block_pin, locals, location, pin,
     end
 
     # @param api_map [ApiMap]
-    # @param block_pin [Pin::Block]
+    # @param closure_pin [Pin::Closure]
     # @param locals [Array<Pin::LocalVariable>]
     # @param location [Location]
     # @param pin [Pin::Method]
     # @param params [Hash{String => [nil, Hash]}]
     # @param kwargs [Hash{Symbol => Source::Chain}]
     # @return [Array<Problem>]
-    def kwrestarg_problems_for(api_map, block_pin, locals, location, pin, params, kwargs)
+    def kwrestarg_problems_for(api_map, closure_pin, locals, location, pin, params, kwargs)
       result = []
       kwargs.each_pair do |pname, argchain|
         next unless params.key?(pname.to_s)
         ptype = params[pname.to_s][:qualified]
-        argtype = argchain.infer(api_map, block_pin, locals)
-        if argtype.defined? && ptype && !any_types_match?(api_map, ptype, argtype)
+        ptype = ptype.self_to_type(pin.context)
+        argtype = argchain.infer(api_map, closure_pin, locals)
+        argtype = argtype.self_to_type(closure_pin.context)
+        if argtype.defined? && ptype && !arg_conforms_to?(argtype, ptype)
           result.push Problem.new(location, "Wrong argument type for #{pin.path}: #{pname} expected #{ptype}, received #{argtype}")
         end
       end
       result
     end
 
-    # @param pin [Pin::Method]
+    # @param param_details [Hash{String => Hash{Symbol => String, ComplexType}}]
+    # @param pin [Pin::Method, Pin::Signature]
+    # @return [void]
+    def add_restkwarg_param_tag_details(param_details, pin)
+      # see if we have additional tags to pay attention to from YARD -
+      # e.g., kwargs in a **restkwargs splat
+      tags = pin.docstring.tags(:param)
+      tags.each do |tag|
+        next if param_details.key? tag.name.to_s
+        next if tag.types.nil?
+        param_details[tag.name.to_s] = {
+          tagged: tag.types.join(', '),
+          qualified: Solargraph::ComplexType.try_parse(*tag.types).qualify(api_map, pin.full_context.namespace)
+        }
+      end
+    end
+
+    # @param pin [Pin::Signature]
     # @return [Hash{String => Hash{Symbol => String, ComplexType}}]
-    def param_hash(pin)
+    def signature_param_details(pin)
       # @type [Hash{String => Hash{Symbol => String, ComplexType}}]
       result = {}
       pin.parameters.each do |param|
@@ -485,44 +555,49 @@ def param_hash(pin)
           qualified: type
         }
       end
-      # see if we have additional tags to pay attention to from YARD -
-      # e.g., kwargs in a **restkwargs splat
-      tags = pin.docstring.tags(:param)
-      tags.each do |tag|
-        next if result.key? tag.name.to_s
-        next if tag.types.nil?
-        result[tag.name.to_s] = {
-          tagged: tag.types.join(', '),
-          qualified: Solargraph::ComplexType.try_parse(*tag.types).qualify(api_map, pin.full_context.namespace)
-        }
-      end
       result
     end
 
+    # The original signature defines the parameters, but other
+    # signatures and method pins can help by adding type information
+    #
+    # @param param_details [Hash{String => Hash{Symbol => String, ComplexType}}]
+    # @param param_names [Array<String>]
+    # @param new_param_details [Hash{String => Hash{Symbol => String, ComplexType}}]
+    #
+    # @return [void]
+    def add_to_param_details(param_details, param_names, new_param_details)
+      new_param_details.each do |param_name, details|
+        next unless param_names.include?(param_name)
+
+        param_details[param_name] ||= {}
+        param_details[param_name][:tagged] ||= details[:tagged]
+        param_details[param_name][:qualified] ||= details[:qualified]
+      end
+    end
+
+    # @param signature [Pin::Signature]
     # @param pins [Array<Pin::Method>]
+    # @param method_pin_stack [Array<Pin::Method>]
+    #
     # @return [Hash{String => Hash{Symbol => String, ComplexType}}]
-    def first_param_hash(pins)
-      return {} if pins.empty?
-      first_pin_type = pins.first.typify(api_map)
-      first_pin = pins.first.proxy first_pin_type
-      param_names = first_pin.parameter_names
-      results = param_hash(first_pin)
-      pins[1..].each do |pin|
-        # @todo this assignment from parametric use of Hash should not lose its generic
-        # @type [Hash{String => Hash{Symbol => BasicObject}}]
+    def param_details_from_stack(signature, method_pin_stack)
+      signature_type = signature.typify(api_map)
+      signature = signature.proxy signature_type
+      param_details = signature_param_details(signature)
+      param_names = signature.parameter_names
+
+      method_pin_stack.each do |method_pin|
+        add_restkwarg_param_tag_details(param_details, method_pin)
 
         # documentation of types in superclasses should fail back to
         # subclasses if the subclass hasn't documented something
-        superclass_results = param_hash(pin)
-        superclass_results.each do |param_name, details|
-          next unless param_names.include?(param_name)
-
-          results[param_name] ||= {}
-          results[param_name][:tagged] ||= details[:tagged]
-          results[param_name][:qualified] ||= details[:qualified]
+        method_pin.signatures.each do |sig|
+          add_restkwarg_param_tag_details(param_details, sig)
+          add_to_param_details param_details, param_names, signature_param_details(sig)
         end
       end
-      results
+      param_details
     end
 
     # @param pin [Pin::Base]
@@ -548,17 +623,17 @@ def declared_externally? pin
       return true if pin.assignment.nil?
       chain = Solargraph::Parser.chain(pin.assignment, filename)
       rng = Solargraph::Range.from_node(pin.assignment)
-      block_pin = source_map.locate_block_pin(rng.start.line, rng.start.column)
+      closure_pin = source_map.locate_closure_pin(rng.start.line, rng.start.column)
       location = Location.new(filename, Range.from_node(pin.assignment))
       locals = source_map.locals_at(location)
-      type = chain.infer(api_map, block_pin, locals)
+      type = chain.infer(api_map, closure_pin, locals)
       if type.undefined? && !rules.ignore_all_undefined?
         base = chain
         missing = chain
         found = nil
         closest = ComplexType::UNDEFINED
         until base.links.first.undefined?
-          found = base.define(api_map, block_pin, locals).first
+          found = base.define(api_map, closure_pin, locals).first
           break if found
           missing = base
           base = base.base
diff --git a/lib/solargraph/type_checker/checks.rb b/lib/solargraph/type_checker/checks.rb
deleted file mode 100644
index de402978b..000000000
--- a/lib/solargraph/type_checker/checks.rb
+++ /dev/null
@@ -1,124 +0,0 @@
-# frozen_string_literal: true
-
-module Solargraph
-  class TypeChecker
-    # Helper methods for performing type checks
-    #
-    module Checks
-      module_function
-
-      # Compare an expected type with an inferred type. Common usage is to
-      # check if the type declared in a method's @return tag matches the type
-      # inferred from static analysis of the code.
-      #
-      # @param api_map [ApiMap]
-      # @param expected [ComplexType]
-      # @param inferred [ComplexType]
-      # @return [Boolean]
-      def types_match? api_map, expected, inferred
-        return true if expected.to_s == inferred.to_s
-        matches = []
-        expected.each do |exp|
-          found = false
-          inferred.each do |inf|
-            # if api_map.super_and_sub?(fuzz(inf), fuzz(exp))
-            if either_way?(api_map, inf, exp)
-              found = true
-              matches.push inf
-              break
-            end
-          end
-          return false unless found
-        end
-        inferred.each do |inf|
-          next if matches.include?(inf)
-          found = false
-          expected.each do |exp|
-            # if api_map.super_and_sub?(fuzz(inf), fuzz(exp))
-            if either_way?(api_map, inf, exp)
-              found = true
-              break
-            end
-          end
-          return false unless found
-        end
-        true
-      end
-
-      # @param api_map [ApiMap]
-      # @param expected [ComplexType]
-      # @param inferred [ComplexType]
-      # @return [Boolean]
-      def any_types_match? api_map, expected, inferred
-        expected = expected.downcast_to_literal_if_possible
-        inferred = inferred.downcast_to_literal_if_possible
-        return duck_types_match?(api_map, expected, inferred) if expected.duck_type?
-        # walk through the union expected type and see if any members
-        # of the union match the inferred type
-        expected.each do |exp|
-          next if exp.duck_type?
-          # @todo: there should be a level of typechecking where all
-          #   unique types in the inferred must match one of the
-          #   expected unique types
-          inferred.each do |inf|
-            # return true if exp == inf || api_map.super_and_sub?(fuzz(inf), fuzz(exp))
-            return true if exp == inf || either_way?(api_map, inf, exp)
-          end
-        end
-        false
-      end
-
-      # @param api_map [ApiMap]
-      # @param inferred [ComplexType]
-      # @param expected [ComplexType]
-      # @return [Boolean]
-      def all_types_match? api_map, inferred, expected
-        expected = expected.downcast_to_literal_if_possible
-        inferred = inferred.downcast_to_literal_if_possible
-        return duck_types_match?(api_map, expected, inferred) if expected.duck_type?
-        inferred.each do |inf|
-          next if inf.duck_type?
-          return false unless expected.any? { |exp| exp == inf || either_way?(api_map, inf, exp) }
-        end
-        true
-      end
-
-      # @param api_map [ApiMap]
-      # @param expected [ComplexType]
-      # @param inferred [ComplexType]
-      # @return [Boolean]
-      def duck_types_match? api_map, expected, inferred
-        raise ArgumentError, 'Expected type must be duck type' unless expected.duck_type?
-        expected.each do |exp|
-          next unless exp.duck_type?
-          quack = exp.to_s[1..-1]
-          return false if api_map.get_method_stack(inferred.namespace, quack, scope: inferred.scope).empty?
-        end
-        true
-      end
-
-      # @param type [ComplexType::UniqueType]
-      # @return [String]
-      def fuzz type
-        if type.parameters?
-          type.name
-        else
-          type.tag
-        end
-      end
-
-      # @param api_map [ApiMap]
-      # @param cls1 [ComplexType::UniqueType]
-      # @param cls2 [ComplexType::UniqueType]
-      # @return [Boolean]
-      def either_way?(api_map, cls1, cls2)
-        # @todo there should be a level of typechecking which uses the
-        #   full tag with parameters to determine compatibility
-        f1 = cls1.name
-        f2 = cls2.name
-        api_map.type_include?(f1, f2) || api_map.super_and_sub?(f1, f2) || api_map.super_and_sub?(f2, f1)
-        # api_map.type_include?(f1, f2) || api_map.super_and_sub?(f1, f2) || api_map.super_and_sub?(f2, f1)
-      end
-    end
-  end
-end
diff --git a/lib/solargraph/type_checker/param_def.rb b/lib/solargraph/type_checker/param_def.rb
deleted file mode 100644
index 2c626270a..000000000
--- a/lib/solargraph/type_checker/param_def.rb
+++ /dev/null
@@ -1,35 +0,0 @@
-# frozen_string_literal: true
-
-module Solargraph
-  class TypeChecker
-    # Data about a method parameter definition. This is the information from
-    # the args list in the def call, not the `@param` tags.
-    #
-    class ParamDef
-      # @return [String]
-      attr_reader :name
-
-      # @return [Symbol]
-      attr_reader :type
-
-      def initialize name, type
-        @name = name
-        @type = type
-      end
-
-      class << self
-        # Get an array of ParamDefs from a method pin.
-        #
-        # @param pin [Solargraph::Pin::Method]
-        # @return [Array<ParamDef>]
-        def from pin
-          result = []
-          pin.parameters.each do |par|
-            result.push ParamDef.new(par.name, par.decl)
-          end
-          result
-        end
-      end
-    end
-  end
-end
diff --git a/lib/solargraph/type_checker/rules.rb b/lib/solargraph/type_checker/rules.rb
index 8f15037d5..5290c8c12 100644
--- a/lib/solargraph/type_checker/rules.rb
+++ b/lib/solargraph/type_checker/rules.rb
@@ -54,11 +54,31 @@ def validate_tags?
         rank > LEVELS[:normal]
       end
 
-      def require_all_return_types_match_inferred?
+      def require_inferred_type_params?
         rank >= LEVELS[:alpha]
       end
 
-      # We keep this at strong because if you added an @sg-ignore to
+      def require_all_unique_types_match_declared?
+        rank >= LEVELS[:alpha]
+      end
+
+      def require_no_undefined_args?
+        rank >= LEVELS[:alpha]
+      end
+
+      def require_generics_resolved?
+        rank >= LEVELS[:alpha]
+      end
+
+      def require_interfaces_resolved?
+        rank >= LEVELS[:alpha]
+      end
+
+      def require_downcasts?
+        rank >= LEVELS[:alpha]
+      end
+
+      # We keep this at strong because if you added an @ sg-ignore to
       # address a strong-level issue, then ran at a lower level, you'd
       # get a false positive - we don't run stronger level checks than
       # requested for performance reasons
diff --git a/lib/solargraph/version.rb b/lib/solargraph/version.rb
index 94cc1b851..7473b20b9 100755
--- a/lib/solargraph/version.rb
+++ b/lib/solargraph/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Solargraph
-  VERSION = '0.56.2'
+  VERSION = '0.57.alpha'
 end
diff --git a/lib/solargraph/workspace.rb b/lib/solargraph/workspace.rb
index ffd653d96..8b57177c9 100644
--- a/lib/solargraph/workspace.rb
+++ b/lib/solargraph/workspace.rb
@@ -2,6 +2,7 @@
 
 require 'open3'
 require 'json'
+require 'yaml'
 
 module Solargraph
   # A workspace consists of the files in a project's directory and the
@@ -9,38 +10,107 @@ module Solargraph
   # in an associated Library or ApiMap.
   #
   class Workspace
+    include Logging
+
     autoload :Config, 'solargraph/workspace/config'
+    autoload :Gemspecs, 'solargraph/workspace/gemspecs'
+    autoload :RequirePaths, 'solargraph/workspace/require_paths'
 
     # @return [String]
     attr_reader :directory
 
-    # The require paths associated with the workspace.
-    #
-    # @return [Array<String>]
-    attr_reader :require_paths
-
-    # @return [Array<String>]
-    attr_reader :gemnames
-    alias source_gems gemnames
-
-    # @param directory [String]
+    # @param directory [String] TODO: Document and test '' and '*' semantics
     # @param config [Config, nil]
     # @param server [Hash]
     def initialize directory = '', config = nil, server = {}
-      @directory = directory
+      raise ArgumentError, 'directory must be a String' unless directory.is_a?(String)
+
+      @directory = if ['*', ''].include?(directory)
+                     directory
+                   else
+                     File.absolute_path(directory)
+                   end
       @config = config
       @server = server
       load_sources
-      @gemnames = []
-      @require_paths = generate_require_paths
       require_plugins
     end
 
+    # The require paths associated with the workspace.
+    #
+    # @return [Array<String>]
+    def require_paths
+      # @todo are the semantics of '*' the same as '', meaning 'don't send back any require paths'?
+      @require_paths ||= RequirePaths.new(directory_or_nil, config).generate
+    end
+
     # @return [Solargraph::Workspace::Config]
     def config
       @config ||= Solargraph::Workspace::Config.new(directory)
     end
 
+    # @param out [IO, nil] output stream for logging
+    # @param gemspec [Gem::Specification]
+    # @return [Array<Gem::Specification>]
+    def fetch_dependencies gemspec, out: $stderr
+      gemspecs.fetch_dependencies(gemspec, out: out)
+    end
+
+    # @return [Solargraph::PinCache]
+    def pin_cache
+      @pin_cache ||= fresh_pincache
+    end
+
+    # @param require [String] The string sent to 'require' in the code to resolve, e.g. 'rails', 'bundler/require'
+    # @return [Array<Gem::Specification>]
+    def resolve_require require
+      gemspecs.resolve_require(require)
+    end
+
+    # @param stdlib_name [String]
+    #
+    # @return [Array<String>]
+    def stdlib_dependencies stdlib_name
+      gemspecs.stdlib_dependencies(stdlib_name)
+    end
+
+    # @return [Environ]
+    def global_environ
+      # empty docmap, since the result needs to work in any possible
+      # context here
+      @global_environ ||= Convention.for_global(DocMap.new([], self, out: nil))
+    end
+
+    # @param gemspec [Gem::Specification, Bundler::LazySpecification]
+    # @param out [IO, nil] output stream for logging
+    # @param rebuild [Boolean] whether to rebuild the pins even if they are cached
+    #
+    # @return [void]
+    def cache_gem gemspec, out: nil, rebuild: false
+      pin_cache.cache_gem(gemspec: gemspec, out: out, rebuild: rebuild)
+    end
+
+    # @param gemspec [Gem::Specification, Bundler::LazySpecification]
+    # @param out [IO, nil] output stream for logging
+    #
+    # @return [void]
+    def uncache_gem gemspec, out: nil
+      pin_cache.uncache_gem(gemspec, out: out)
+    end
+
+    # @return [Solargraph::PinCache]
+    def fresh_pincache
+      PinCache.new(rbs_collection_path: rbs_collection_path,
+                   rbs_collection_config_path: rbs_collection_config_path,
+                   yard_plugins: yard_plugins,
+                   directory: directory)
+    end
+
+    # @return [Array<String>]
+    def yard_plugins
+      @yard_plugins ||= global_environ.yard_plugins.sort.uniq
+    end
+
     # Merge the source. A merge will update the existing source for the file
     # or add it to the sources if the workspace is configured to include it.
     # The source is ignored if the configuration excludes it.
@@ -111,23 +181,6 @@ def would_require? path
       false
     end
 
-    # True if the workspace contains at least one gemspec file.
-    #
-    # @return [Boolean]
-    def gemspec?
-      !gemspecs.empty?
-    end
-
-    # Get an array of all gemspec files in the workspace.
-    #
-    # @return [Array<String>]
-    def gemspecs
-      return [] if directory.empty? || directory == '*'
-      @gemspecs ||= Dir[File.join(directory, '**/*.gemspec')].select do |gs|
-        config.allow? gs
-      end
-    end
-
     # @return [String, nil]
     def rbs_collection_path
       @gem_rbs_collection ||= read_rbs_collection_path
@@ -135,12 +188,44 @@ def rbs_collection_path
 
     # @return [String, nil]
     def rbs_collection_config_path
-      @rbs_collection_config_path ||= begin
-        unless directory.empty? || directory == '*'
-          yaml_file = File.join(directory, 'rbs_collection.yaml')
-          yaml_file if File.file?(yaml_file)
+      @rbs_collection_config_path ||=
+        begin
+          unless directory.empty? || directory == '*'
+            yaml_file = File.join(directory, 'rbs_collection.yaml')
+            yaml_file if File.file?(yaml_file)
+          end
         end
+    end
+
+    # @param name [String]
+    # @param version [String, nil]
+    #
+    # @return [Gem::Specification, nil]
+    def find_gem name, version = nil
+      gemspecs.find_gem(name, version)
+    end
+
+    # @param out [IO, nil] output stream for logging
+    # @param rebuild [Boolean] whether to rebuild the pins even if they are cached
+    # @return [void]
+    def cache_all_for_workspace! out, rebuild: false
+      PinCache.cache_core(out: out) unless PinCache.core?
+
+      # @type [Array<Gem::Specification>]
+      gem_specs = gemspecs.all_gemspecs_from_bundle
+      # try any possible standard libraries, but be quiet about it
+      stdlib_specs = pin_cache.possible_stdlibs.map { |stdlib| gemspecs.find_gem(stdlib, out: nil) }.compact
+      specs = (gem_specs + stdlib_specs)
+      specs.each do |spec|
+        pin_cache.cache_gem(gemspec: spec, rebuild: rebuild, out: out) unless pin_cache.cached?(spec)
       end
+      out&.puts "Documentation cached for all #{specs.length} gems."
+
+      # do this after so that we prefer stdlib requires from gems,
+      # which are likely to be newer and have more pins
+      pin_cache.cache_all_stdlibs(out: out)
+
+      out&.puts "Documentation cached for core, standard library and gems."
     end
 
     # Synchronize the workspace from the provided updater.
@@ -156,12 +241,15 @@ def command_path
       server['commandPath'] || 'solargraph'
     end
 
-    # True if the workspace has a root Gemfile.
-    #
-    # @todo Handle projects with custom Bundler/Gemfile setups (see DocMap#gemspecs_required_from_bundler)
-    #
-    def gemfile?
-      directory && File.file?(File.join(directory, 'Gemfile'))
+    # @return [String, nil]
+    def directory_or_nil
+      return nil if directory.empty? || directory == '*'
+      directory
+    end
+
+    # @return [Solargraph::Workspace::Gemspecs]
+    def gemspecs
+      @gemspecs ||= Solargraph::Workspace::Gemspecs.new(directory_or_nil)
     end
 
     private
@@ -182,7 +270,10 @@ def load_sources
       source_hash.clear
       unless directory.empty? || directory == '*'
         size = config.calculated.length
-        raise WorkspaceTooLargeError, "The workspace is too large to index (#{size} files, #{config.max_files} max)" if config.max_files > 0 and size > config.max_files
+        if config.max_files > 0 and size > config.max_files
+          raise WorkspaceTooLargeError,
+                "The workspace is too large to index (#{size} files, #{config.max_files} max)"
+        end
         config.calculated.each do |filename|
           begin
             source_hash[filename] = Solargraph::Source.load(filename)
@@ -193,48 +284,6 @@ def load_sources
       end
     end
 
-    # Generate require paths from gemspecs if they exist or assume the default
-    # lib directory.
-    #
-    # @return [Array<String>]
-    def generate_require_paths
-      return configured_require_paths unless gemspec?
-      result = []
-      gemspecs.each do |file|
-        base = File.dirname(file)
-        # HACK: Evaluating gemspec files violates the goal of not running
-        #   workspace code, but this is how Gem::Specification.load does it
-        #   anyway.
-        cmd = ['ruby', '-e', "require 'rubygems'; require 'json'; spec = eval(File.read('#{file}'), TOPLEVEL_BINDING, '#{file}'); return unless Gem::Specification === spec; puts({name: spec.name, paths: spec.require_paths}.to_json)"]
-        o, e, s = Open3.capture3(*cmd)
-        if s.success?
-          begin
-            hash = o && !o.empty? ? JSON.parse(o.split("\n").last) : {}
-            next if hash.empty?
-            @gemnames.push hash['name']
-            result.concat(hash['paths'].map { |path| File.join(base, path) })
-          rescue StandardError => e
-            Solargraph.logger.warn "Error reading #{file}: [#{e.class}] #{e.message}"
-          end
-        else
-          Solargraph.logger.warn "Error reading #{file}"
-          Solargraph.logger.warn e
-        end
-      end
-      result.concat(config.require_paths.map { |p| File.join(directory, p) })
-      result.push File.join(directory, 'lib') if result.empty?
-      result
-    end
-
-    # Get additional require paths defined in the configuration.
-    #
-    # @return [Array<String>]
-    def configured_require_paths
-      return ['lib'] if directory.empty?
-      return [File.join(directory, 'lib')] if config.require_paths.empty?
-      config.require_paths.map { |p| File.join(directory, p) }
-    end
-
     # @return [void]
     def require_plugins
       config.plugins.each do |plugin|
diff --git a/lib/solargraph/workspace/gemspecs.rb b/lib/solargraph/workspace/gemspecs.rb
new file mode 100644
index 000000000..be765127a
--- /dev/null
+++ b/lib/solargraph/workspace/gemspecs.rb
@@ -0,0 +1,358 @@
+# frozen_string_literal: true
+
+require 'rubygems'
+require 'bundler'
+
+module Solargraph
+  class Workspace
+    # Manages determining which gemspecs are available in a workspace
+    class Gemspecs
+      include Logging
+
+      attr_reader :directory, :preferences
+
+      # @param directory [String, nil] If nil, assume no bundle is present
+      # @param preferences [Array<Gem::Specification>]
+      def initialize directory, preferences: []
+        # @todo an issue with both external bundles and the potential
+        #   preferences feature is that bundler gives you a 'clean'
+        #   rubygems environment with only the specified versions
+        #   installed.  Possible alternatives:
+        #
+        #   *) prompt the user to run solargraph outside of bundler
+        #      and treat all bundles as external
+        #   *) reinstall the needed gems dynamically each time
+        #   *) manipulate the rubygems/bundler environment
+        @directory = directory && File.absolute_path(directory)
+        # @todo implement preferences as a config-exposed feature
+        @preferences = preferences
+      end
+
+      # Take the path given to a 'require' statement in a source file
+      # and return the Gem::Specifications which will be brought into
+      # scope with it, so we can load pins for them.
+      #
+      # @param require [String] The string sent to 'require' in the code to resolve, e.g. 'rails', 'bundler/require'
+      # @return [::Array<Gem::Specification>, nil]
+      def resolve_require require
+        return nil if require.empty?
+
+        # This is added in the parser when it sees 'Bundler.require' -
+        # see https://bundler.io/guides/bundler_setup.html '
+        #
+        # @todo handle different arguments to Bundler.require
+        return auto_required_gemspecs_from_bundler if require == 'bundler/require'
+
+        # Determine gem name based on the require path
+        file = "lib/#{require}.rb"
+        spec_with_path = Gem::Specification.find_by_path(file)
+
+        all_gemspecs = all_gemspecs_from_bundle
+
+        gem_names_to_try = [
+          spec_with_path&.name,
+          require.tr('/', '-'),
+          require.split('/').first
+        ].compact.uniq
+        gem_names_to_try.each do |gem_name|
+          gemspec = all_gemspecs.find { |gemspec| gemspec.name == gem_name }
+          return [gemspec_or_preference(gemspec)] if gemspec
+
+          begin
+            gemspec = Gem::Specification.find_by_name(gem_name)
+            return [gemspec_or_preference(gemspec)] if gemspec
+          rescue Gem::MissingSpecError
+            logger.debug "Gem #{gem_name} not found in the current Ruby environment"
+          end
+
+          # look ourselves just in case this is hanging out somewhere
+          # that find_by_path doesn't index'
+          gemspec = all_gemspecs.find do |spec|
+            spec = to_gem_specification(spec) unless spec.respond_to?(:files)
+
+            spec&.files&.any? { |gemspec_file| file == gemspec_file }
+          end
+          return [gemspec_or_preference(gemspec)] if gemspec
+        end
+
+        nil
+      end
+
+      # @param stdlib_name [String]
+      #
+      # @return [Array<String>]
+      def stdlib_dependencies stdlib_name
+        deps = RbsMap::StdlibMap.stdlib_dependencies(stdlib_name, nil) || []
+        deps.map { |dep| dep['name'] }.compact
+      end
+
+      # @param name [String]
+      # @param version [String, nil]
+      # @param out [IO, nil] output stream for logging
+      #
+      # @return [Gem::Specification, nil]
+      def find_gem name, version = nil, out: $stderr
+        gemspec = all_gemspecs_from_bundle.find { |gemspec| gemspec.name == name && gemspec.version == version }
+        return gemspec if gemspec
+
+        gemspec = all_gemspecs_from_bundle.find { |gemspec| gemspec.name == name }
+        return gemspec if gemspec
+
+        resolve_gem_ignoring_local_bundle name, version, out: out
+      end
+
+      # @param gemspec [Gem::Specification]
+      # @param out[IO, nil] output stream for logging
+      #
+      # @return [Array<Gem::Specification>]
+      def fetch_dependencies gemspec, out: $stderr
+        gemspecs = all_gemspecs_from_bundle
+
+        # @type [Hash{String => Gem::Specification}]
+        deps_so_far = {}
+
+        # @param runtime_dep [Gem::Dependency]
+        # @param deps [Hash{String => Gem::Specification}]
+        gem_dep_gemspecs = only_runtime_dependencies(gemspec).each_with_object(deps_so_far) do |runtime_dep, deps|
+          next if deps[runtime_dep.name]
+
+          Solargraph.logger.info "Adding #{runtime_dep.name} dependency for #{gemspec.name}"
+          dep = gemspecs.find { |dep| dep.name == runtime_dep.name }
+          dep ||= Gem::Specification.find_by_name(runtime_dep.name, runtime_dep.requirement)
+        rescue Gem::MissingSpecError
+          dep = resolve_gem_ignoring_local_bundle runtime_dep.name, out: out
+        ensure
+          next unless dep
+
+          fetch_dependencies(dep, out: out).each { |sub_dep| deps[sub_dep.name] ||= sub_dep }
+          deps[dep.name] ||= dep
+        end
+        # RBS tracks implicit dependencies, like how the YAML standard
+        # library implies pulling in the psych library.
+        stdlib_deps = RbsMap::StdlibMap.stdlib_dependencies(gemspec.name, gemspec.version) || []
+        stdlib_dep_gemspecs = stdlib_deps.map { |dep| find_gem(dep['name'], dep['version']) }.compact
+        (gem_dep_gemspecs.values.compact + stdlib_dep_gemspecs).uniq(&:name)
+      end
+
+      # Returns all gemspecs directly depended on by this workspace's
+      # bundle (does not include transitive dependencies).
+      #
+      # @return [Array<Gem::Specification, Bundler::LazySpecification, Bundler::StubSpecification>]
+      def all_gemspecs_from_bundle
+        return [] unless directory
+
+        @all_gemspecs_from_bundle ||=
+          if in_this_bundle?
+            all_gemspecs_from_this_bundle
+          else
+            all_gemspecs_from_external_bundle
+          end
+      end
+
+      # @return [Hash{Gem::Specification, Bundler::LazySpecification, Bundler::StubSpecification => Gem::Specification}]
+      def self.gem_specification_cache
+        @gem_specification_cache ||= {}
+      end
+
+      private
+
+      # @param specish [Gem::Specification, Bundler::LazySpecification, Bundler::StubSpecification]
+      # @return [Gem::Specification, nil]
+      def to_gem_specification specish
+        # print time including milliseconds
+        self.class.gem_specification_cache[specish] ||= case specish
+                                                        when Gem::Specification
+                                                          # yay!
+                                                          specish
+                                                        when Bundler::LazySpecification
+                                                          # materializing didn't work.  Let's look in the local
+                                                          # rubygems without bundler's help
+                                                          resolve_gem_ignoring_local_bundle specish.name,
+                                                                                            specish.version
+                                                        when Bundler::StubSpecification
+                                                          # turns a Bundler::StubSpecification into a
+                                                          # Gem::StubSpecification into a Gem::Specification
+                                                          specish = specish.stub
+                                                          if specish.respond_to?(:spec)
+                                                            specish.spec
+                                                          else
+                                                            # turn the crank again
+                                                            to_gem_specification(specish)
+                                                          end
+                                                        else
+                                                          @@warned_on_gem_type ||=
+                                                            false
+                                                          unless @@warned_on_gem_type
+                                                            logger.warn 'Unexpected type while resolving gem: ' \
+                                                                        "#{specish.class}"
+                                                            @@warned_on_gem_type = true
+                                                          end
+                                                          nil
+                                                        end
+      end
+
+      # @param command [String] The expression to evaluate in the external bundle
+      # @sg-ignore Need a JSON type
+      # @yield [undefined, nil]
+      def query_external_bundle command
+        Solargraph.with_clean_env do
+          cmd = [
+            'ruby', '-e',
+            "require 'bundler'; require 'json'; Dir.chdir('#{directory}') { puts begin; #{command}; end.to_json }"
+          ]
+          o, e, s = Open3.capture3(*cmd)
+          if s.success?
+            Solargraph.logger.debug "External bundle: #{o}"
+            o && !o.empty? ? JSON.parse(o.split("\n").last) : nil
+          else
+            Solargraph.logger.warn e
+            raise BundleNotFoundError, "Failed to load gems from bundle at #{directory}"
+          end
+        end
+      end
+
+      def in_this_bundle?
+        Bundler.definition&.lockfile&.to_s&.start_with?(directory) # rubocop:disable Style/SafeNavigationChainLength
+      end
+
+      # @return [Array<Gem::Specification, Bundler::LazySpecification, Bundler::StubSpecification>]
+      def all_gemspecs_from_this_bundle
+        # Find only the gems bundler is now using
+        specish_objects = Bundler.definition.locked_gems.specs
+        if specish_objects.first.respond_to?(:materialize_for_installation)
+          specish_objects = specish_objects.map(&:materialize_for_installation)
+        end
+        specish_objects.map do |specish|
+          if specish.respond_to?(:name) && specish.respond_to?(:version) && specish.respond_to?(:gem_dir)
+            # duck type is good enough for outside uses!
+            specish
+          else
+            to_gem_specification(specish)
+          end
+        end.compact
+      end
+
+      # @return [Array<Gem::Specification, Bundler::LazySpecification, Bundler::StubSpecification>]
+      def auto_required_gemspecs_from_bundler
+        return [] unless directory
+
+        logger.info 'Fetching gemspecs autorequired from Bundler (bundler/require)'
+        @auto_required_gemspecs_from_bundler ||=
+          if in_this_bundle?
+            auto_required_gemspecs_from_this_bundle
+          else
+            auto_required_gemspecs_from_external_bundle
+          end
+      end
+
+      # @return [Array<Gem::Specification, Bundler::LazySpecification, Bundler::StubSpecification>]
+      def auto_required_gemspecs_from_this_bundle
+        # Adapted from require() in lib/bundler/runtime.rb
+        dep_names = Bundler.definition.dependencies.select do |dep|
+          dep.groups.include?(:default) && dep.should_include?
+        end.map(&:name)
+
+        all_gemspecs_from_bundle.select { |gemspec| dep_names.include?(gemspec.name) }
+      end
+
+      # @return [Array<Gem::Specification, Bundler::LazySpecification, Bundler::StubSpecification>]
+      def auto_required_gemspecs_from_external_bundle
+        @auto_required_gemspecs_from_external_bundle ||=
+          begin
+            logger.info 'Fetching auto-required gemspecs from Bundler (bundler/require)'
+            command =
+              'Bundler.definition.dependencies' \
+              '.select { |dep| dep.groups.include?(:default) && dep.should_include? }' \
+              '.map(&:name)'
+            # @sg-ignore
+            # @type [Array<String>]
+            dep_names = query_external_bundle command
+
+            all_gemspecs_from_bundle.select { |gemspec| dep_names.include?(gemspec.name) }
+          end
+      end
+
+      # @param gemspec [Gem::Specification]
+      # @return [Array<Gem::Dependency>]
+      def only_runtime_dependencies gemspec
+        unless gemspec.respond_to?(:dependencies) && gemspec.respond_to?(:development_dependencies)
+          gemspec = to_gem_specification(gemspec)
+        end
+        return [] if gemspec.nil?
+
+        gemspec.dependencies - gemspec.development_dependencies
+      end
+
+      # @todo Should this be using Gem::SpecFetcher and pull them automatically?
+      #
+      # @param name [String]
+      # @param version [String, nil]
+      # @param out [IO, nil] output stream for logging
+      #
+      # @return [Gem::Specification, nil]
+      def resolve_gem_ignoring_local_bundle name, version = nil, out: $stderr
+        Gem::Specification.find_by_name(name, version)
+      rescue Gem::MissingSpecError
+        begin
+          Gem::Specification.find_by_name(name)
+        rescue Gem::MissingSpecError
+          stdlibmap = RbsMap::StdlibMap.new(name)
+          unless stdlibmap.resolved?
+            gem_desc = name
+            gem_desc += ":#{version}" if version
+            out&.puts "Please install the gem #{gem_desc} in Solargraph's Ruby environment"
+          end
+          nil # either not here or in stdlib
+        end
+      end
+
+      # @return [Array<Gem::Specification>]
+      # @sg-ignore
+      def all_gemspecs_from_external_bundle
+        @all_gemspecs_from_external_bundle ||=
+          begin
+            logger.info 'Fetching gemspecs required from external bundle'
+
+            command = 'specish_objects = Bundler.definition.locked_gems&.specs; ' \
+                      'if specish_objects.first.respond_to?(:materialize_for_installation);' \
+                      'specish_objects = specish_objects.map(&:materialize_for_installation);' \
+                      'end;' \
+                      'specish_objects.map { |specish| [specish.name, specish.version] }'
+            query_external_bundle(command).map do |name, version|
+              resolve_gem_ignoring_local_bundle(name, version)
+            end.compact
+          rescue Solargraph::BundleNotFoundError => e
+            Solargraph.logger.info e.message
+            Solargraph.logger.debug e.backtrace.join("\n")
+            []
+          end
+      end
+
+      # @return [Hash{String => Gem::Specification}]
+      def preference_map
+        @preference_map ||= preferences.to_h { |gemspec| [gemspec.name, gemspec] }
+      end
+
+      # @param gemspec [Gem::Specification]
+      #
+      # @return [Gem::Specification]
+      def gemspec_or_preference gemspec
+        return gemspec unless preference_map.key?(gemspec.name)
+        return gemspec if gemspec.version == preference_map[gemspec.name].version
+
+        change_gemspec_version gemspec, preference_map[gemspec.name].version
+      end
+
+      # @param gemspec [Gem::Specification]
+      # @param version [String]
+      # @return [Gem::Specification]
+      def change_gemspec_version gemspec, version
+        Gem::Specification.find_by_name(gemspec.name, "= #{version}")
+      rescue Gem::MissingSpecError
+        Solargraph.logger.info "Gem #{gemspec.name} version #{version.inspect} not found. " \
+                               "Using #{gemspec.version} instead"
+        gemspec
+      end
+    end
+  end
+end
diff --git a/lib/solargraph/workspace/require_paths.rb b/lib/solargraph/workspace/require_paths.rb
new file mode 100644
index 000000000..c8eea161b
--- /dev/null
+++ b/lib/solargraph/workspace/require_paths.rb
@@ -0,0 +1,97 @@
+# frozen_string_literal: true
+
+require 'open3'
+
+module Solargraph
+  # A workspace consists of the files in a project's directory and the
+  # project's configuration. It provides a Source for each file to be used
+  # in an associated Library or ApiMap.
+  #
+  class Workspace
+    # Manages determining which gemspecs are available in a workspace
+    class RequirePaths
+      attr_reader :directory, :config
+
+      # @param directory [String, nil]
+      # @param config [Config, nil]
+      def initialize directory, config
+        @directory = directory
+        @config = config
+      end
+
+      # Generate require paths from gemspecs if they exist or assume the default
+      # lib directory.
+      #
+      # @return [Array<String>]
+      def generate
+        result = require_paths_from_gemspec_files
+        return configured_require_paths if result.empty?
+        result.concat(config.require_paths.map { |p| File.join(directory, p) }) if config
+        result
+      end
+
+      private
+
+      # @return [Array<String>]
+      def require_paths_from_gemspec_files
+        results = []
+        gemspec_file_paths.each do |gemspec_file_path|
+          results.concat require_path_from_gemspec_file(gemspec_file_path)
+        end
+        results
+      end
+
+      # Get an array of all gemspec files in the workspace.
+      #
+      # @return [Array<String>]
+      def gemspec_file_paths
+        return [] if directory.nil?
+        @gemspec_file_paths ||= Dir[File.join(directory, '**/*.gemspec')].select do |gs|
+          config.nil? || config.allow?(gs)
+        end
+      end
+
+      # Get additional require paths defined in the configuration.
+      #
+      # @return [Array<String>]
+      def configured_require_paths
+        return ['lib'] unless directory
+        return [File.join(directory, 'lib')] if !config || config.require_paths.empty?
+        config.require_paths.map { |p| File.join(directory, p) }
+      end
+
+      # Generate require paths from gemspecs if they exist or assume the default
+      # lib directory.
+      #
+      # @param gemspec_file_path [String]
+      # @return [Array<String>]
+      def require_path_from_gemspec_file gemspec_file_path
+        base = File.dirname(gemspec_file_path)
+        # HACK: Evaluating gemspec files violates the goal of not running
+        #   workspace code, but this is how Gem::Specification.load does it
+        #   anyway.
+        cmd = ['ruby', '-e',
+               "require 'rubygems'; " \
+               "require 'json'; " \
+               "spec = eval(File.read('#{gemspec_file_path}'), TOPLEVEL_BINDING, '#{gemspec_file_path}'); " \
+               'return unless Gem::Specification === spec; ' \
+               'puts({name: spec.name, paths: spec.require_paths}.to_json)']
+        o, e, s = Open3.capture3(*cmd)
+        if s.success?
+          begin
+            hash = o && !o.empty? ? JSON.parse(o.split("\n").last) : {}
+            return [] if hash.empty?
+            hash['paths'].map { |path| File.join(base, path) }
+          rescue StandardError => e
+            Solargraph.logger.warn "Error reading #{gemspec_file_path}: [#{e.class}] #{e.message}"
+            []
+          end
+        else
+          Solargraph.logger.warn "Error reading #{gemspec_file_path}"
+          Solargraph.logger.warn e
+          []
+        end
+      end
+    end
+  end
+end
diff --git a/lib/solargraph/yard_map/mapper/to_method.rb b/lib/solargraph/yard_map/mapper/to_method.rb
index df431bb3c..d8e3b8b43 100644
--- a/lib/solargraph/yard_map/mapper/to_method.rb
+++ b/lib/solargraph/yard_map/mapper/to_method.rb
@@ -27,8 +27,8 @@ def self.make code_object, name = nil, scope = nil, visibility = nil, closure =
           final_scope = scope || code_object.scope
           override_key = [closure.path, final_scope, name]
           final_visibility = VISIBILITY_OVERRIDE[override_key]
-          final_visibility ||= VISIBILITY_OVERRIDE[override_key[0..-2]]
-          final_visibility ||= :private if closure.path == 'Kernel' && Kernel.private_instance_methods(false).include?(name)
+          final_visibility ||= VISIBILITY_OVERRIDE[[closure.path, final_scope]]
+          final_visibility ||= :private if closure.path == 'Kernel' && Kernel.private_instance_methods(false).include?(name.to_sym)
           final_visibility ||= visibility
           final_visibility ||= :private if code_object.module_function? && final_scope == :instance
           final_visibility ||= :public if code_object.module_function? && final_scope == :class
diff --git a/lib/solargraph/yardoc.rb b/lib/solargraph/yardoc.rb
index d8e597978..50f212f13 100644
--- a/lib/solargraph/yardoc.rb
+++ b/lib/solargraph/yardoc.rb
@@ -8,44 +8,54 @@ module Solargraph
   module Yardoc
     module_function
 
-    # Build and cache a gem's yardoc and return the path. If the cache already
-    # exists, do nothing and return the path.
+    # Build and save a gem's yardoc into a given path.
     #
-    # @param yard_plugins [Array<String>] The names of YARD plugins to use.
+    # @param gem_yardoc_path [String] the path to the yardoc cache of a particular gem
+    # @param yard_plugins [Array<String>]
     # @param gemspec [Gem::Specification]
-    # @return [String] The path to the cached yardoc.
-    def cache(yard_plugins, gemspec)
-      path = PinCache.yardoc_path gemspec
-      return path if cached?(gemspec)
+    #
+    # @return [void]
+    def build_docs gem_yardoc_path, yard_plugins, gemspec
+      return if docs_built?(gem_yardoc_path)
 
-      Solargraph.logger.info "Caching yardoc for #{gemspec.name} #{gemspec.version}"
-      cmd = "yardoc --db #{path} --no-output --plugin solargraph"
+      Solargraph.logger.info "Saving yardoc for #{gemspec.name} #{gemspec.version} into #{gem_yardoc_path}"
+      cmd = "yardoc --db #{gem_yardoc_path} --no-output --plugin solargraph"
       yard_plugins.each { |plugin| cmd << " --plugin #{plugin}" }
       Solargraph.logger.debug { "Running: #{cmd}" }
       # @todo set these up to run in parallel
-      #
-      # @sg-ignore RBS gem doesn't reflect that Open3.* also include
-      #   kwopts from Process.spawn()
-      stdout_and_stderr_str, status = Open3.capture2e(cmd, chdir: gemspec.gem_dir)
-      unless status.success?
-        Solargraph.logger.warn { "YARD failed running #{cmd.inspect} in #{gemspec.gem_dir}" }
-        Solargraph.logger.info stdout_and_stderr_str
+      unless File.exist?(gemspec.gem_dir)
+        Solargraph.logger.info { "Bad info from gemspec - #{gemspec.gem_dir} does not exist" }
+        return
       end
-      path
+
+      stdout_and_stderr_str, status = Open3.capture2e(current_bundle_env_tweaks, cmd, chdir: gemspec.gem_dir)
+      return if status.success?
+      Solargraph.logger.warn { "YARD failed running #{cmd.inspect} in #{gemspec.gem_dir}" }
+      Solargraph.logger.info stdout_and_stderr_str
+    end
+
+    # @param gem_yardoc_path [String] the path to the yardoc cache of a particular gem
+    # @param gemspec [Gem::Specification]
+    # @param out [IO, nil] where to log messages
+    # @return [Array<Pin::Base>]
+    def build_pins gem_yardoc_path, gemspec, out: $stderr
+      yardoc = load!(gem_yardoc_path)
+      YardMap::Mapper.new(yardoc, gemspec).map
     end
 
     # True if the gem yardoc is cached.
     #
-    # @param gemspec [Gem::Specification]
-    def cached?(gemspec)
-      yardoc = File.join(PinCache.yardoc_path(gemspec), 'complete')
+    # @param gem_yardoc_path [String]
+    def docs_built? gem_yardoc_path
+      yardoc = File.join(gem_yardoc_path, 'complete')
       File.exist?(yardoc)
     end
 
     # True if another process is currently building the yardoc cache.
     #
-    def processing?(gemspec)
-      yardoc = File.join(PinCache.yardoc_path(gemspec), 'processing')
+    # @param gem_yardoc_path [String] the path to the yardoc cache of a particular gem
+    def processing? gem_yardoc_path
+      yardoc = File.join(gem_yardoc_path, 'processing')
       File.exist?(yardoc)
     end
 
@@ -53,11 +63,28 @@ def processing?(gemspec)
     #
     # @note This method modifies the global YARD registry.
     #
-    # @param gemspec [Gem::Specification]
+    # @param gem_yardoc_path [String] the path to the yardoc cache of a particular gem
     # @return [Array<YARD::CodeObjects::Base>]
-    def load!(gemspec)
-      YARD::Registry.load! PinCache.yardoc_path gemspec
+    def load! gem_yardoc_path
+      YARD::Registry.load! gem_yardoc_path
       YARD::Registry.all
     end
+
+    # If the BUNDLE_GEMFILE environment variable is set, we need to
+    # make sure it's an absolute path, as we'll be changing
+    # directories.
+    #
+    # 'bundle exec' sets an absolute path here, but at least the
+    # overcommit gem does not, breaking on-the-fly documention with a
+    # spawned yardoc command from our current bundle
+    #
+    # @return [Hash{String => String}] a hash of environment variables to override
+    def current_bundle_env_tweaks
+      tweaks = {}
+      if ENV['BUNDLE_GEMFILE'] && !ENV['BUNDLE_GEMFILE'].empty?
+        tweaks['BUNDLE_GEMFILE'] = File.expand_path(ENV['BUNDLE_GEMFILE'])
+      end
+      tweaks
+    end
   end
 end
diff --git a/rbs/fills/bundler/0/bundler.rbs b/rbs/fills/bundler/0/bundler.rbs
new file mode 100644
index 000000000..8b23710d4
--- /dev/null
+++ b/rbs/fills/bundler/0/bundler.rbs
@@ -0,0 +1,4271 @@
+# [`Bundler`](https://docs.ruby-lang.org/en/2.7.0/Bundler.html) provides a
+# consistent environment for Ruby projects by tracking and installing the exact
+# gems and versions that are needed.
+#
+# Since Ruby 2.6, [`Bundler`](https://docs.ruby-lang.org/en/2.7.0/Bundler.html)
+# is a part of Ruby's standard library.
+#
+# Bunder is used by creating *gemfiles* listing all the project dependencies and
+# (optionally) their versions and then using
+#
+# ```ruby
+# require 'bundler/setup'
+# ```
+#
+# or
+# [`Bundler.setup`](https://docs.ruby-lang.org/en/2.7.0/Bundler.html#method-c-setup)
+# to setup environment where only specified gems and their specified versions
+# could be used.
+#
+# See [Bundler website](https://bundler.io/docs.html) for extensive
+# documentation on gemfiles creation and
+# [`Bundler`](https://docs.ruby-lang.org/en/2.7.0/Bundler.html) usage.
+#
+# As a standard library inside project,
+# [`Bundler`](https://docs.ruby-lang.org/en/2.7.0/Bundler.html) could be used
+# for introspection of loaded and required modules.
+module Bundler
+  def self.app_cache: (?untyped custom_path) -> untyped
+
+  def self.app_config_path: () -> untyped
+
+  # Returns absolute location of where binstubs are installed to.
+  def self.bin_path: () -> untyped
+
+  # Returns absolute path of where gems are installed on the filesystem.
+  def self.bundle_path: () -> untyped
+
+  def self.bundler_major_version: () -> untyped
+
+  # @deprecated Use `unbundled\_env` instead
+  def self.clean_env: () -> untyped
+
+  def self.clean_exec: (*untyped args) -> untyped
+
+  def self.clean_system: (*untyped args) -> untyped
+
+  def self.clear_gemspec_cache: () -> untyped
+
+  def self.configure: () -> untyped
+
+  def self.configured_bundle_path: () -> untyped
+
+  # Returns current version of Ruby
+  #
+  # @return [CurrentRuby] Current version of Ruby
+  def self.current_ruby: () -> untyped
+
+  def self.default_bundle_dir: () -> untyped
+
+  def self.default_gemfile: () -> untyped
+
+  def self.default_lockfile: () -> untyped
+
+  def self.definition: (?(::Hash[String, Boolean | nil] | Boolean | nil) unlock) -> Bundler::Definition
+
+  def self.environment: () -> untyped
+
+  def self.feature_flag: () -> untyped
+
+  def self.frozen_bundle?: () -> untyped
+
+  def self.git_present?: () -> untyped
+
+  def self.home: () -> untyped
+
+  def self.install_path: () -> untyped
+
+  def self.load: () -> untyped
+
+  def self.load_gemspec: (untyped file, ?untyped validate) -> untyped
+
+  def self.load_gemspec_uncached: (untyped file, ?untyped validate) -> untyped
+
+  def self.load_marshal: (untyped data) -> untyped
+
+  def self.local_platform: () -> untyped
+
+  def self.locked_gems: () -> untyped
+
+  def self.mkdir_p: (untyped path, ?untyped options) -> untyped
+
+  # @return [Hash] Environment present before
+  # [`Bundler`](https://docs.ruby-lang.org/en/2.7.0/Bundler.html) was activated
+  def self.original_env: () -> untyped
+
+  def self.read_file: (untyped file) -> untyped
+
+  def self.require: (*untyped groups) -> untyped
+
+  def self.require_thor_actions: () -> untyped
+
+  def self.requires_sudo?: () -> untyped
+
+  def self.reset!: () -> untyped
+
+  def self.reset_paths!: () -> untyped
+
+  def self.reset_rubygems!: () -> untyped
+
+  def self.rm_rf: (untyped path) -> untyped
+
+  def self.root: () -> untyped
+
+  def self.ruby_scope: () -> untyped
+
+  def self.rubygems: () -> untyped
+
+  def self.settings: () -> untyped
+
+  def self.setup: (*untyped groups) -> untyped
+
+  def self.specs_path: () -> untyped
+
+  def self.sudo: (untyped str) -> untyped
+
+  def self.system_bindir: () -> untyped
+
+  def self.tmp: (?untyped name) -> untyped
+
+  def self.tmp_home_path: (untyped login, untyped warning) -> untyped
+
+  def self.ui: () -> untyped
+
+  def self.ui=: (untyped ui) -> untyped
+
+  def self.use_system_gems?: () -> untyped
+
+  def self.user_bundle_path: (?untyped dir) -> untyped
+
+  def self.user_cache: () -> untyped
+
+  def self.user_home: () -> untyped
+
+  def self.which: (untyped executable) -> untyped
+
+  # @deprecated Use `with\_unbundled\_env` instead
+  def self.with_clean_env: () { () -> untyped } -> untyped
+
+  def self.with_unbundled_env: () { () -> untyped } -> untyped
+
+  # Run block with environment present before
+  # [`Bundler`](https://docs.ruby-lang.org/en/2.7.0/Bundler.html) was activated
+  def self.with_original_env: () { () -> untyped } -> untyped
+end
+
+Bundler::FREEBSD: untyped
+
+Bundler::NULL: untyped
+
+Bundler::ORIGINAL_ENV: untyped
+
+Bundler::SUDO_MUTEX: untyped
+
+Bundler::VERSION: untyped
+
+Bundler::WINDOWS: untyped
+
+class Bundler::APIResponseMismatchError < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+# Represents metadata from when the
+# [`Bundler`](https://docs.ruby-lang.org/en/2.7.0/Bundler.html) gem was built.
+module Bundler::BuildMetadata
+  # A string representing the date the bundler gem was built.
+  def self.built_at: () -> untyped
+
+  # The SHA for the git commit the bundler gem was built from.
+  def self.git_commit_sha: () -> untyped
+
+  # Whether this is an official release build of
+  # [`Bundler`](https://docs.ruby-lang.org/en/2.7.0/Bundler.html).
+  def self.release?: () -> untyped
+
+  # A hash representation of the build metadata.
+  def self.to_h: () -> untyped
+end
+
+class Bundler::BundlerError < StandardError
+  def self.all_errors: () -> untyped
+
+  def self.status_code: (untyped code) -> untyped
+end
+
+class Bundler::CurrentRuby
+  def jruby?: () -> untyped
+
+  def jruby_18?: () -> untyped
+
+  def jruby_19?: () -> untyped
+
+  def jruby_1?: () -> untyped
+
+  def jruby_20?: () -> untyped
+
+  def jruby_21?: () -> untyped
+
+  def jruby_22?: () -> untyped
+
+  def jruby_23?: () -> untyped
+
+  def jruby_24?: () -> untyped
+
+  def jruby_25?: () -> untyped
+
+  def jruby_26?: () -> untyped
+
+  def jruby_27?: () -> untyped
+
+  def jruby_2?: () -> untyped
+
+  def maglev?: () -> untyped
+
+  def maglev_18?: () -> untyped
+
+  def maglev_19?: () -> untyped
+
+  def maglev_1?: () -> untyped
+
+  def maglev_20?: () -> untyped
+
+  def maglev_21?: () -> untyped
+
+  def maglev_22?: () -> untyped
+
+  def maglev_23?: () -> untyped
+
+  def maglev_24?: () -> untyped
+
+  def maglev_25?: () -> untyped
+
+  def maglev_26?: () -> untyped
+
+  def maglev_27?: () -> untyped
+
+  def maglev_2?: () -> untyped
+
+  def mingw?: () -> untyped
+
+  def mingw_18?: () -> untyped
+
+  def mingw_19?: () -> untyped
+
+  def mingw_1?: () -> untyped
+
+  def mingw_20?: () -> untyped
+
+  def mingw_21?: () -> untyped
+
+  def mingw_22?: () -> untyped
+
+  def mingw_23?: () -> untyped
+
+  def mingw_24?: () -> untyped
+
+  def mingw_25?: () -> untyped
+
+  def mingw_26?: () -> untyped
+
+  def mingw_27?: () -> untyped
+
+  def mingw_2?: () -> untyped
+
+  def mri?: () -> untyped
+
+  def mri_18?: () -> untyped
+
+  def mri_19?: () -> untyped
+
+  def mri_1?: () -> untyped
+
+  def mri_20?: () -> untyped
+
+  def mri_21?: () -> untyped
+
+  def mri_22?: () -> untyped
+
+  def mri_23?: () -> untyped
+
+  def mri_24?: () -> untyped
+
+  def mri_25?: () -> untyped
+
+  def mri_26?: () -> untyped
+
+  def mri_27?: () -> untyped
+
+  def mri_2?: () -> untyped
+
+  def mswin64?: () -> untyped
+
+  def mswin64_18?: () -> untyped
+
+  def mswin64_19?: () -> untyped
+
+  def mswin64_1?: () -> untyped
+
+  def mswin64_20?: () -> untyped
+
+  def mswin64_21?: () -> untyped
+
+  def mswin64_22?: () -> untyped
+
+  def mswin64_23?: () -> untyped
+
+  def mswin64_24?: () -> untyped
+
+  def mswin64_25?: () -> untyped
+
+  def mswin64_26?: () -> untyped
+
+  def mswin64_27?: () -> untyped
+
+  def mswin64_2?: () -> untyped
+
+  def mswin?: () -> untyped
+
+  def mswin_18?: () -> untyped
+
+  def mswin_19?: () -> untyped
+
+  def mswin_1?: () -> untyped
+
+  def mswin_20?: () -> untyped
+
+  def mswin_21?: () -> untyped
+
+  def mswin_22?: () -> untyped
+
+  def mswin_23?: () -> untyped
+
+  def mswin_24?: () -> untyped
+
+  def mswin_25?: () -> untyped
+
+  def mswin_26?: () -> untyped
+
+  def mswin_27?: () -> untyped
+
+  def mswin_2?: () -> untyped
+
+  def on_18?: () -> untyped
+
+  def on_19?: () -> untyped
+
+  def on_1?: () -> untyped
+
+  def on_20?: () -> untyped
+
+  def on_21?: () -> untyped
+
+  def on_22?: () -> untyped
+
+  def on_23?: () -> untyped
+
+  def on_24?: () -> untyped
+
+  def on_25?: () -> untyped
+
+  def on_26?: () -> untyped
+
+  def on_27?: () -> untyped
+
+  def on_2?: () -> untyped
+
+  def rbx?: () -> untyped
+
+  def rbx_18?: () -> untyped
+
+  def rbx_19?: () -> untyped
+
+  def rbx_1?: () -> untyped
+
+  def rbx_20?: () -> untyped
+
+  def rbx_21?: () -> untyped
+
+  def rbx_22?: () -> untyped
+
+  def rbx_23?: () -> untyped
+
+  def rbx_24?: () -> untyped
+
+  def rbx_25?: () -> untyped
+
+  def rbx_26?: () -> untyped
+
+  def rbx_27?: () -> untyped
+
+  def rbx_2?: () -> untyped
+
+  def ruby?: () -> untyped
+
+  def ruby_18?: () -> untyped
+
+  def ruby_19?: () -> untyped
+
+  def ruby_1?: () -> untyped
+
+  def ruby_20?: () -> untyped
+
+  def ruby_21?: () -> untyped
+
+  def ruby_22?: () -> untyped
+
+  def ruby_23?: () -> untyped
+
+  def ruby_24?: () -> untyped
+
+  def ruby_25?: () -> untyped
+
+  def ruby_26?: () -> untyped
+
+  def ruby_27?: () -> untyped
+
+  def ruby_2?: () -> untyped
+
+  def truffleruby?: () -> untyped
+
+  def truffleruby_18?: () -> untyped
+
+  def truffleruby_19?: () -> untyped
+
+  def truffleruby_1?: () -> untyped
+
+  def truffleruby_20?: () -> untyped
+
+  def truffleruby_21?: () -> untyped
+
+  def truffleruby_22?: () -> untyped
+
+  def truffleruby_23?: () -> untyped
+
+  def truffleruby_24?: () -> untyped
+
+  def truffleruby_25?: () -> untyped
+
+  def truffleruby_26?: () -> untyped
+
+  def truffleruby_27?: () -> untyped
+
+  def truffleruby_2?: () -> untyped
+
+  def x64_mingw?: () -> untyped
+
+  def x64_mingw_18?: () -> untyped
+
+  def x64_mingw_19?: () -> untyped
+
+  def x64_mingw_1?: () -> untyped
+
+  def x64_mingw_20?: () -> untyped
+
+  def x64_mingw_21?: () -> untyped
+
+  def x64_mingw_22?: () -> untyped
+
+  def x64_mingw_23?: () -> untyped
+
+  def x64_mingw_24?: () -> untyped
+
+  def x64_mingw_25?: () -> untyped
+
+  def x64_mingw_26?: () -> untyped
+
+  def x64_mingw_27?: () -> untyped
+
+  def x64_mingw_2?: () -> untyped
+end
+
+Bundler::CurrentRuby::KNOWN_MAJOR_VERSIONS: untyped
+
+Bundler::CurrentRuby::KNOWN_MINOR_VERSIONS: untyped
+
+Bundler::CurrentRuby::KNOWN_PLATFORMS: untyped
+
+class Bundler::CyclicDependencyError < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+class Bundler::Definition
+  include ::Bundler::GemHelpers
+
+  def add_current_platform: () -> untyped
+
+  def add_platform: (untyped platform) -> untyped
+
+  def current_dependencies: () -> untyped
+
+  def dependencies: () -> Array[::Bundler::Dependency]
+
+  def ensure_equivalent_gemfile_and_lockfile: (?untyped explicit_flag) -> untyped
+
+  def find_indexed_specs: (untyped current_spec) -> untyped
+
+  def find_resolved_spec: (untyped current_spec) -> untyped
+
+  def gem_version_promoter: () -> untyped
+
+  def gemfiles: () -> untyped
+
+  def groups: () -> untyped
+
+  def has_local_dependencies?: () -> untyped
+
+  def has_rubygems_remotes?: () -> untyped
+
+  def index: () -> untyped
+
+  def initialize: (untyped lockfile, untyped dependencies, untyped sources, untyped unlock, ?untyped ruby_version, ?untyped optional_groups, ?untyped gemfiles) -> void
+
+  def lock: (untyped file, ?untyped preserve_unknown_sections) -> untyped
+
+  def locked_bundler_version: () -> untyped
+
+  def locked_deps: () -> untyped
+
+  def locked_gems: () -> Bundler::LockfileParser
+
+  def locked_ruby_version: () -> untyped
+
+  def locked_ruby_version_object: () -> untyped
+
+  def lockfile: () -> Pathname
+
+  def missing_specs: () -> untyped
+
+  def missing_specs?: () -> untyped
+
+  def new_platform?: () -> untyped
+
+  def new_specs: () -> untyped
+
+  def nothing_changed?: () -> untyped
+
+  def platforms: () -> untyped
+
+  def remove_platform: (untyped platform) -> untyped
+
+  def removed_specs: () -> untyped
+
+  def requested_specs: () -> untyped
+
+  def requires: () -> untyped
+
+  # Resolve all the dependencies specified in Gemfile. It ensures that
+  # dependencies that have been already resolved via locked file and are fresh
+  # are reused when resolving dependencies
+  #
+  # @return [SpecSet] resolved dependencies
+  def resolve: () -> untyped
+
+  def resolve_remotely!: () -> untyped
+
+  def resolve_with_cache!: () -> untyped
+
+  def ruby_version: () -> untyped
+
+  def spec_git_paths: () -> untyped
+
+  # For given dependency list returns a SpecSet with Gemspec of all the required
+  # dependencies.
+  #
+  # ```
+  # 1. The method first resolves the dependencies specified in Gemfile
+  # 2. After that it tries and fetches gemspec of resolved dependencies
+  # ```
+  #
+  # @return [Bundler::SpecSet]
+  def specs: () -> untyped
+
+  def specs_for: (untyped groups) -> untyped
+
+  def to_lock: () -> untyped
+
+  def unlocking?: () -> untyped
+
+  def validate_platforms!: () -> untyped
+
+  def validate_ruby!: () -> untyped
+
+  def validate_runtime!: () -> untyped
+
+  def self.build: (untyped gemfile, untyped lockfile, untyped unlock) -> untyped
+end
+
+class Bundler::DepProxy
+  def ==: (untyped other) -> untyped
+
+  def __platform: () -> untyped
+
+  def dep: () -> untyped
+
+  def eql?: (untyped other) -> untyped
+
+  def hash: () -> untyped
+
+  def initialize: (untyped dep, untyped platform) -> void
+
+  def name: () -> untyped
+
+  def requirement: () -> untyped
+
+  def to_s: () -> untyped
+
+  def type: () -> untyped
+end
+
+class Bundler::Dependency < Gem::Dependency
+  def autorequire: () -> untyped
+
+  def current_env?: () -> untyped
+
+  def current_platform?: () -> untyped
+
+  def gem_platforms: (untyped valid_platforms) -> untyped
+
+  def gemfile: () -> untyped
+
+  def groups: () -> untyped
+
+  def initialize: (untyped name, untyped version, ?untyped options) { () -> untyped } -> void
+
+  def platforms: () -> untyped
+
+  def should_include?: () -> untyped
+
+  def specific?: () -> untyped
+
+  def to_lock: () -> untyped
+end
+
+Bundler::Dependency::PLATFORM_MAP: untyped
+
+Bundler::Dependency::REVERSE_PLATFORM_MAP: untyped
+
+class Bundler::DeprecatedError < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+class Bundler::Dsl
+  @source: untyped
+
+  @sources: untyped
+
+  @git_sources: untyped
+
+  @dependencies: untyped
+
+  @groups: untyped
+
+  @install_conditionals: untyped
+
+  @optional_groups: untyped
+
+  @platforms: untyped
+
+  @env: untyped
+
+  @ruby_version: untyped
+
+  @gemspecs: untyped
+
+  @gemfile: untyped
+
+  @gemfiles: untyped
+
+  @valid_keys: untyped
+
+  include RubyDsl
+
+  def self.evaluate: (untyped gemfile, untyped lockfile, untyped unlock) -> untyped
+
+  VALID_PLATFORMS: untyped
+
+  VALID_KEYS: ::Array["group" | "groups" | "git" | "path" | "glob" | "name" | "branch" | "ref" | "tag" | "require" | "submodules" | "platform" | "platforms" | "source" | "install_if" | "force_ruby_platform"]
+
+  GITHUB_PULL_REQUEST_URL: ::Regexp
+
+  GITLAB_MERGE_REQUEST_URL: ::Regexp
+
+  attr_reader gemspecs: untyped
+
+  attr_reader gemfile: untyped
+
+  attr_accessor dependencies: untyped
+
+  def initialize: () -> void
+
+  def eval_gemfile: (untyped gemfile, ?untyped? contents) -> untyped
+
+  def gemspec: (?path: ::String, ?glob: ::String, ?name: ::String, ?development_group: ::Symbol) -> void
+
+  def gem: (untyped name, *untyped args) -> void
+
+  def source: (::String source, ?type: ::Symbol) ?{ (?) -> untyped } -> void
+
+  def git_source: (untyped name) ?{ (?) -> untyped } -> untyped
+
+  def path: (untyped path, ?::Hash[untyped, untyped] options) ?{ (?) -> untyped } -> untyped
+
+  def git: (untyped uri, ?::Hash[untyped, untyped] options) ?{ (?) -> untyped } -> untyped
+
+  def github: (untyped repo, ?::Hash[untyped, untyped] options) ?{ () -> untyped } -> untyped
+
+  def to_definition: (untyped lockfile, untyped unlock) -> untyped
+
+  def group: (*untyped args) { () -> untyped } -> untyped
+
+  def install_if: (*untyped args) { () -> untyped } -> untyped
+
+  def platforms: (*untyped platforms) { () -> untyped } -> untyped
+
+  alias platform platforms
+
+  def env: (untyped name) { () -> untyped } -> untyped
+
+  def plugin: (*untyped args) -> nil
+
+  def method_missing: (untyped name, *untyped args) -> untyped
+
+  def check_primary_source_safety: () -> untyped
+
+  private
+
+  def add_dependency: (untyped name, ?untyped? version, ?::Hash[untyped, untyped] options) -> (nil | untyped)
+
+  def with_gemfile: (untyped gemfile) { (untyped) -> untyped } -> untyped
+
+  def add_git_sources: () -> untyped
+
+  def with_source: (untyped source) ?{ () -> untyped } -> untyped
+
+  def normalize_hash: (untyped opts) -> untyped
+
+  def valid_keys: () -> untyped
+
+  def normalize_options: (untyped name, untyped version, untyped opts) -> untyped
+
+  def normalize_group_options: (untyped opts, untyped groups) -> untyped
+
+  def validate_keys: (untyped command, untyped opts, untyped valid_keys) -> (true | untyped)
+
+  def normalize_source: (untyped source) -> untyped
+
+  def deprecate_legacy_windows_platforms: (untyped platforms) -> (nil | untyped)
+
+  def check_path_source_safety: () -> (nil | untyped)
+
+  def check_rubygems_source_safety: () -> (untyped | nil)
+
+  def multiple_global_source_warning: () -> untyped
+
+  class DSLError < GemfileError
+    @status_code: untyped
+
+    @description: untyped
+
+    @dsl_path: untyped
+
+    @backtrace: untyped
+
+    @contents: untyped
+
+    @to_s: untyped
+
+    # @return [::String] the description that should be presented to the user.
+    #
+    attr_reader description: ::String
+
+    # @return [::String] the path of the dsl file that raised the exception.
+    #
+    attr_reader dsl_path: ::String
+
+    # @return [::Exception] the backtrace of the exception raised by the
+    #         evaluation of the dsl file.
+    #
+    attr_reader backtrace: ::Exception
+
+    # @param [::Exception] backtrace @see backtrace
+    # @param [::String]    dsl_path  @see dsl_path
+    #
+    def initialize: (untyped description, ::String dsl_path, ::Exception backtrace, ?untyped? contents) -> void
+
+    def status_code: () -> untyped
+
+    # @return [::String] the contents of the DSL that cause the exception to
+    #         be raised.
+    #
+    def contents: () -> ::String
+
+    # The message of the exception reports the content of podspec for the
+    # line that generated the original exception.
+    #
+    # @example Output
+    #
+    #   Invalid podspec at `RestKit.podspec` - undefined method
+    #   `exclude_header_search_paths=' for #<Pod::Specification for
+    #   `RestKit/Network (0.9.3)`>
+    #
+    #       from spec-repos/master/RestKit/0.9.3/RestKit.podspec:36
+    #       -------------------------------------------
+    #           # because it would break: #import <CoreData/CoreData.h>
+    #    >      ns.exclude_header_search_paths = 'Code/RestKit.h'
+    #         end
+    #       -------------------------------------------
+    #
+    # @return [::String] the message of the exception.
+    #
+    def to_s: () -> ::String
+
+    private
+
+    def parse_line_number_from_description: () -> ::Array[untyped]
+  end
+
+  def gemfile_root: () -> untyped
+end
+
+# used for Creating Specifications from the Gemcutter Endpoint
+class Bundler::EndpointSpecification < Gem::Specification
+  def __swap__: (untyped spec) -> untyped
+
+  def _local_specification: () -> untyped
+
+  # needed for bundle clean
+  def bindir: () -> untyped
+
+  def checksum: () -> untyped
+
+  def dependencies: () -> untyped
+
+  def dependencies=: (untyped dependencies) -> untyped
+
+  # needed for binstubs
+  def executables: () -> untyped
+
+  # needed for "with native extensions" during install
+  def extensions: () -> untyped
+
+  def fetch_platform: () -> untyped
+
+  def initialize: (untyped name, untyped version, untyped platform, untyped dependencies, ?untyped metadata) -> void
+
+  # needed for inline
+  def load_paths: () -> untyped
+
+  def name: () -> untyped
+
+  def platform: () -> untyped
+
+  # needed for post\_install\_messages during install
+  def post_install_message: () -> untyped
+
+  def remote: () -> untyped
+
+  def remote=: (untyped remote) -> untyped
+
+  # needed for standalone, load required\_paths from local gemspec after the gem
+  # is installed
+  def require_paths: () -> untyped
+
+  def required_ruby_version: () -> untyped
+
+  def required_rubygems_version: () -> untyped
+
+  def source: () -> untyped
+
+  def source=: (untyped source) -> untyped
+
+  def version: () -> untyped
+end
+
+Bundler::EndpointSpecification::Elem: untyped
+
+Bundler::EndpointSpecification::ILLFORMED_MESSAGE: untyped
+
+class Bundler::EnvironmentPreserver
+  # @return [Hash]
+  def backup: () -> untyped
+
+  def initialize: (untyped env, untyped keys) -> void
+
+  # @return [Hash]
+  def restore: () -> untyped
+end
+
+Bundler::EnvironmentPreserver::BUNDLER_KEYS: untyped
+
+Bundler::EnvironmentPreserver::BUNDLER_PREFIX: untyped
+
+Bundler::EnvironmentPreserver::INTENTIONALLY_NIL: untyped
+
+class Bundler::FeatureFlag
+  def allow_bundler_dependency_conflicts?: () -> untyped
+
+  def allow_offline_install?: () -> untyped
+
+  def auto_clean_without_path?: () -> untyped
+
+  def auto_config_jobs?: () -> untyped
+
+  def bundler_10_mode?: () -> untyped
+
+  def bundler_1_mode?: () -> untyped
+
+  def bundler_2_mode?: () -> untyped
+
+  def bundler_3_mode?: () -> untyped
+
+  def bundler_4_mode?: () -> untyped
+
+  def bundler_5_mode?: () -> untyped
+
+  def bundler_6_mode?: () -> untyped
+
+  def bundler_7_mode?: () -> untyped
+
+  def bundler_8_mode?: () -> untyped
+
+  def bundler_9_mode?: () -> untyped
+
+  def cache_all?: () -> untyped
+
+  def cache_command_is_package?: () -> untyped
+
+  def console_command?: () -> untyped
+
+  def default_cli_command: () -> untyped
+
+  def default_install_uses_path?: () -> untyped
+
+  def deployment_means_frozen?: () -> untyped
+
+  def disable_multisource?: () -> untyped
+
+  def error_on_stderr?: () -> untyped
+
+  def forget_cli_options?: () -> untyped
+
+  def global_gem_cache?: () -> untyped
+
+  def init_gems_rb?: () -> untyped
+
+  def initialize: (untyped bundler_version) -> void
+
+  def list_command?: () -> untyped
+
+  def lockfile_uses_separate_rubygems_sources?: () -> untyped
+
+  def only_update_to_newer_versions?: () -> untyped
+
+  def path_relative_to_cwd?: () -> untyped
+
+  def plugins?: () -> untyped
+
+  def prefer_gems_rb?: () -> untyped
+
+  def print_only_version_number?: () -> untyped
+
+  def setup_makes_kernel_gem_public?: () -> untyped
+
+  def skip_default_git_sources?: () -> untyped
+
+  def specific_platform?: () -> untyped
+
+  def suppress_install_using_messages?: () -> untyped
+
+  def unlock_source_unlocks_spec?: () -> untyped
+
+  def update_requires_all_flag?: () -> untyped
+
+  def use_gem_version_promoter_for_major_updates?: () -> untyped
+
+  def viz_command?: () -> untyped
+end
+
+# # fileutils.rb
+#
+# Copyright (c) 2000-2007 Minero Aoki
+#
+# This program is free software. You can distribute/modify this program under
+# the same terms of ruby.
+#
+# ## module [`Bundler::FileUtils`](https://docs.ruby-lang.org/en/2.7.0/Bundler/FileUtils.html)
+#
+# Namespace for several file utility methods for copying, moving, removing, etc.
+#
+# ### [`Module`](https://docs.ruby-lang.org/en/2.7.0/Module.html) Functions
+#
+# ```ruby
+# require 'bundler/vendor/fileutils/lib/fileutils'
+#
+# Bundler::FileUtils.cd(dir, **options)
+# Bundler::FileUtils.cd(dir, **options) {|dir| block }
+# Bundler::FileUtils.pwd()
+# Bundler::FileUtils.mkdir(dir, **options)
+# Bundler::FileUtils.mkdir(list, **options)
+# Bundler::FileUtils.mkdir_p(dir, **options)
+# Bundler::FileUtils.mkdir_p(list, **options)
+# Bundler::FileUtils.rmdir(dir, **options)
+# Bundler::FileUtils.rmdir(list, **options)
+# Bundler::FileUtils.ln(target, link, **options)
+# Bundler::FileUtils.ln(targets, dir, **options)
+# Bundler::FileUtils.ln_s(target, link, **options)
+# Bundler::FileUtils.ln_s(targets, dir, **options)
+# Bundler::FileUtils.ln_sf(target, link, **options)
+# Bundler::FileUtils.cp(src, dest, **options)
+# Bundler::FileUtils.cp(list, dir, **options)
+# Bundler::FileUtils.cp_r(src, dest, **options)
+# Bundler::FileUtils.cp_r(list, dir, **options)
+# Bundler::FileUtils.mv(src, dest, **options)
+# Bundler::FileUtils.mv(list, dir, **options)
+# Bundler::FileUtils.rm(list, **options)
+# Bundler::FileUtils.rm_r(list, **options)
+# Bundler::FileUtils.rm_rf(list, **options)
+# Bundler::FileUtils.install(src, dest, **options)
+# Bundler::FileUtils.chmod(mode, list, **options)
+# Bundler::FileUtils.chmod_R(mode, list, **options)
+# Bundler::FileUtils.chown(user, group, list, **options)
+# Bundler::FileUtils.chown_R(user, group, list, **options)
+# Bundler::FileUtils.touch(list, **options)
+# ```
+#
+# Possible `options` are:
+#
+# `:force`
+# :   forced operation (rewrite files if exist, remove directories if not empty,
+#     etc.);
+# `:verbose`
+# :   print command to be run, in bash syntax, before performing it;
+# `:preserve`
+# :   preserve object's group, user and modification time on copying;
+# `:noop`
+# :   no changes are made (usable in combination with `:verbose` which will
+#     print the command to run)
+#
+#
+# Each method documents the options that it honours. See also
+# [`::commands`](https://docs.ruby-lang.org/en/2.7.0/FileUtils.html#method-c-commands),
+# [`::options`](https://docs.ruby-lang.org/en/2.7.0/FileUtils.html#method-c-options)
+# and
+# [`::options_of`](https://docs.ruby-lang.org/en/2.7.0/FileUtils.html#method-c-options_of)
+# methods to introspect which command have which options.
+#
+# All methods that have the concept of a "source" file or directory can take
+# either one file or a list of files in that argument. See the method
+# documentation for examples.
+#
+# There are some 'low level' methods, which do not accept keyword arguments:
+#
+# ```ruby
+# Bundler::FileUtils.copy_entry(src, dest, preserve = false, dereference_root = false, remove_destination = false)
+# Bundler::FileUtils.copy_file(src, dest, preserve = false, dereference = true)
+# Bundler::FileUtils.copy_stream(srcstream, deststream)
+# Bundler::FileUtils.remove_entry(path, force = false)
+# Bundler::FileUtils.remove_entry_secure(path, force = false)
+# Bundler::FileUtils.remove_file(path, force = false)
+# Bundler::FileUtils.compare_file(path_a, path_b)
+# Bundler::FileUtils.compare_stream(stream_a, stream_b)
+# Bundler::FileUtils.uptodate?(file, cmp_list)
+# ```
+#
+# ## module [`Bundler::FileUtils::Verbose`](https://docs.ruby-lang.org/en/2.7.0/Bundler/FileUtils/Verbose.html)
+#
+# This module has all methods of
+# [`Bundler::FileUtils`](https://docs.ruby-lang.org/en/2.7.0/Bundler/FileUtils.html)
+# module, but it outputs messages before acting. This equates to passing the
+# `:verbose` flag to methods in
+# [`Bundler::FileUtils`](https://docs.ruby-lang.org/en/2.7.0/Bundler/FileUtils.html).
+#
+# ## module [`Bundler::FileUtils::NoWrite`](https://docs.ruby-lang.org/en/2.7.0/Bundler/FileUtils/NoWrite.html)
+#
+# This module has all methods of
+# [`Bundler::FileUtils`](https://docs.ruby-lang.org/en/2.7.0/Bundler/FileUtils.html)
+# module, but never changes files/directories.  This equates to passing the
+# `:noop` flag to methods in
+# [`Bundler::FileUtils`](https://docs.ruby-lang.org/en/2.7.0/Bundler/FileUtils.html).
+#
+# ## module [`Bundler::FileUtils::DryRun`](https://docs.ruby-lang.org/en/2.7.0/Bundler/FileUtils/DryRun.html)
+#
+# This module has all methods of
+# [`Bundler::FileUtils`](https://docs.ruby-lang.org/en/2.7.0/Bundler/FileUtils.html)
+# module, but never changes files/directories.  This equates to passing the
+# `:noop` and `:verbose` flags to methods in
+# [`Bundler::FileUtils`](https://docs.ruby-lang.org/en/2.7.0/Bundler/FileUtils.html).
+module Bundler::FileUtils
+  include ::Bundler::FileUtils::StreamUtils_
+
+  extend ::Bundler::FileUtils::StreamUtils_
+
+  def self.cd: (untyped dir, ?verbose: untyped verbose) { () -> untyped } -> untyped
+
+  def self.chdir: (untyped dir, ?verbose: untyped verbose) { () -> untyped } -> untyped
+
+  def self.chmod: (untyped mode, untyped list, ?noop: untyped noop, ?verbose: untyped verbose) -> untyped
+
+  def self.chmod_R: (untyped mode, untyped list, ?noop: untyped noop, ?verbose: untyped verbose, ?force: untyped force) -> untyped
+
+  def self.chown: (untyped user, untyped group, untyped list, ?noop: untyped noop, ?verbose: untyped verbose) -> untyped
+
+  def self.chown_R: (untyped user, untyped group, untyped list, ?noop: untyped noop, ?verbose: untyped verbose, ?force: untyped force) -> untyped
+
+  def self.cmp: (untyped a, untyped b) -> untyped
+
+  def self.collect_method: (untyped opt) -> untyped
+
+  # Returns an [`Array`](https://docs.ruby-lang.org/en/2.7.0/Array.html) of
+  # names of high-level methods that accept any keyword arguments.
+  #
+  # ```ruby
+  # p Bundler::FileUtils.commands  #=> ["chmod", "cp", "cp_r", "install", ...]
+  # ```
+  def self.commands: () -> untyped
+
+  def self.compare_file: (untyped a, untyped b) -> untyped
+
+  def self.compare_stream: (untyped a, untyped b) -> untyped
+
+  def self.copy: (untyped src, untyped dest, ?preserve: untyped preserve, ?noop: untyped noop, ?verbose: untyped verbose) -> untyped
+
+  def self.copy_entry: (untyped src, untyped dest, ?untyped preserve, ?untyped dereference_root, ?untyped remove_destination) -> untyped
+
+  def self.copy_file: (untyped src, untyped dest, ?untyped preserve, ?untyped dereference) -> untyped
+
+  def self.copy_stream: (untyped src, untyped dest) -> untyped
+
+  def self.cp: (untyped src, untyped dest, ?preserve: untyped preserve, ?noop: untyped noop, ?verbose: untyped verbose) -> untyped
+
+  def self.cp_r: (untyped src, untyped dest, ?preserve: untyped preserve, ?noop: untyped noop, ?verbose: untyped verbose, ?dereference_root: untyped dereference_root, ?remove_destination: untyped remove_destination) -> untyped
+
+  # Alias for:
+  # [`pwd`](https://docs.ruby-lang.org/en/2.7.0/FileUtils.html#method-i-pwd)
+  def self.getwd: () -> untyped
+
+  def self.have_option?: (untyped mid, untyped opt) -> untyped
+
+  def self.identical?: (untyped a, untyped b) -> untyped
+
+  def self.install: (untyped src, untyped dest, ?mode: untyped mode, ?owner: untyped owner, ?group: untyped group, ?preserve: untyped preserve, ?noop: untyped noop, ?verbose: untyped verbose) -> untyped
+
+  def self.link: (untyped src, untyped dest, ?force: untyped force, ?noop: untyped noop, ?verbose: untyped verbose) -> untyped
+
+  def self.ln: (untyped src, untyped dest, ?force: untyped force, ?noop: untyped noop, ?verbose: untyped verbose) -> untyped
+
+  def self.ln_s: (untyped src, untyped dest, ?force: untyped force, ?noop: untyped noop, ?verbose: untyped verbose) -> untyped
+
+  def self.ln_sf: (untyped src, untyped dest, ?noop: untyped noop, ?verbose: untyped verbose) -> untyped
+
+  def self.makedirs: (untyped list, ?mode: untyped mode, ?noop: untyped noop, ?verbose: untyped verbose) -> untyped
+
+  def self.mkdir: (untyped list, ?mode: untyped mode, ?noop: untyped noop, ?verbose: untyped verbose) -> untyped
+
+  def self.mkdir_p: (untyped list, ?mode: untyped mode, ?noop: untyped noop, ?verbose: untyped verbose) -> untyped
+
+  def self.mkpath: (untyped list, ?mode: untyped mode, ?noop: untyped noop, ?verbose: untyped verbose) -> untyped
+
+  def self.move: (untyped src, untyped dest, ?force: untyped force, ?noop: untyped noop, ?verbose: untyped verbose, ?secure: untyped secure) -> untyped
+
+  def self.mv: (untyped src, untyped dest, ?force: untyped force, ?noop: untyped noop, ?verbose: untyped verbose, ?secure: untyped secure) -> untyped
+
+  # Returns an [`Array`](https://docs.ruby-lang.org/en/2.7.0/Array.html) of
+  # option names.
+  #
+  # ```ruby
+  # p Bundler::FileUtils.options  #=> ["noop", "force", "verbose", "preserve", "mode"]
+  # ```
+  def self.options: () -> untyped
+
+  def self.options_of: (untyped mid) -> untyped
+
+  def self.private_module_function: (untyped name) -> untyped
+
+  # Returns the name of the current directory.
+  #
+  # Also aliased as:
+  # [`getwd`](https://docs.ruby-lang.org/en/2.7.0/FileUtils.html#method-c-getwd)
+  def self.pwd: () -> untyped
+
+  def self.remove: (untyped list, ?force: untyped force, ?noop: untyped noop, ?verbose: untyped verbose) -> untyped
+
+  def self.remove_dir: (untyped path, ?untyped force) -> untyped
+
+  def self.remove_entry: (untyped path, ?untyped force) -> untyped
+
+  def self.remove_entry_secure: (untyped path, ?untyped force) -> untyped
+
+  def self.remove_file: (untyped path, ?untyped force) -> untyped
+
+  def self.rm: (untyped list, ?force: untyped force, ?noop: untyped noop, ?verbose: untyped verbose) -> untyped
+
+  def self.rm_f: (untyped list, ?noop: untyped noop, ?verbose: untyped verbose) -> untyped
+
+  def self.rm_r: (untyped list, ?force: untyped force, ?noop: untyped noop, ?verbose: untyped verbose, ?secure: untyped secure) -> untyped
+
+  def self.rm_rf: (untyped list, ?noop: untyped noop, ?verbose: untyped verbose, ?secure: untyped secure) -> untyped
+
+  def self.rmdir: (untyped list, ?parents: untyped parents, ?noop: untyped noop, ?verbose: untyped verbose) -> untyped
+
+  def self.rmtree: (untyped list, ?noop: untyped noop, ?verbose: untyped verbose, ?secure: untyped secure) -> untyped
+
+  def self.safe_unlink: (untyped list, ?noop: untyped noop, ?verbose: untyped verbose) -> untyped
+
+  def self.symlink: (untyped src, untyped dest, ?force: untyped force, ?noop: untyped noop, ?verbose: untyped verbose) -> untyped
+
+  def self.touch: (untyped list, ?noop: untyped noop, ?verbose: untyped verbose, ?mtime: untyped mtime, ?nocreate: untyped nocreate) -> untyped
+
+  def self.uptodate?: (untyped new, untyped old_list) -> untyped
+end
+
+Bundler::FileUtils::LOW_METHODS: untyped
+
+Bundler::FileUtils::METHODS: untyped
+
+Bundler::FileUtils::OPT_TABLE: untyped
+
+# This module has all methods of
+# [`Bundler::FileUtils`](https://docs.ruby-lang.org/en/2.7.0/Bundler/FileUtils.html)
+# module, but never changes files/directories, with printing message before
+# acting. This equates to passing the `:noop` and `:verbose` flag to methods in
+# [`Bundler::FileUtils`](https://docs.ruby-lang.org/en/2.7.0/Bundler/FileUtils.html).
+module Bundler::FileUtils::DryRun
+  include ::Bundler::FileUtils::LowMethods
+
+  include ::Bundler::FileUtils
+
+  include ::Bundler::FileUtils::StreamUtils_
+
+  extend ::Bundler::FileUtils::DryRun
+
+  extend ::Bundler::FileUtils::LowMethods
+
+  extend ::Bundler::FileUtils
+
+  extend ::Bundler::FileUtils::StreamUtils_
+
+  def self.cd: (*untyped _) -> untyped
+
+  def self.chdir: (*untyped _) -> untyped
+
+  def self.chmod: (*untyped args, **untyped options) -> untyped
+
+  def self.chmod_R: (*untyped args, **untyped options) -> untyped
+
+  def self.chown: (*untyped args, **untyped options) -> untyped
+
+  def self.chown_R: (*untyped args, **untyped options) -> untyped
+
+  def self.cmp: (*untyped _) -> untyped
+
+  def self.compare_file: (*untyped _) -> untyped
+
+  def self.compare_stream: (*untyped _) -> untyped
+
+  def self.copy: (*untyped args, **untyped options) -> untyped
+
+  def self.copy_entry: (*untyped _) -> untyped
+
+  def self.copy_file: (*untyped _) -> untyped
+
+  def self.copy_stream: (*untyped _) -> untyped
+
+  def self.cp: (*untyped args, **untyped options) -> untyped
+
+  def self.cp_r: (*untyped args, **untyped options) -> untyped
+
+  def self.getwd: (*untyped _) -> untyped
+
+  def self.identical?: (*untyped _) -> untyped
+
+  def self.install: (*untyped args, **untyped options) -> untyped
+
+  def self.link: (*untyped args, **untyped options) -> untyped
+
+  def self.ln: (*untyped args, **untyped options) -> untyped
+
+  def self.ln_s: (*untyped args, **untyped options) -> untyped
+
+  def self.ln_sf: (*untyped args, **untyped options) -> untyped
+
+  def self.makedirs: (*untyped args, **untyped options) -> untyped
+
+  def self.mkdir: (*untyped args, **untyped options) -> untyped
+
+  def self.mkdir_p: (*untyped args, **untyped options) -> untyped
+
+  def self.mkpath: (*untyped args, **untyped options) -> untyped
+
+  def self.move: (*untyped args, **untyped options) -> untyped
+
+  def self.mv: (*untyped args, **untyped options) -> untyped
+
+  def self.pwd: (*untyped _) -> untyped
+
+  def self.remove: (*untyped args, **untyped options) -> untyped
+
+  def self.remove_dir: (*untyped _) -> untyped
+
+  def self.remove_entry: (*untyped _) -> untyped
+
+  def self.remove_entry_secure: (*untyped _) -> untyped
+
+  def self.remove_file: (*untyped _) -> untyped
+
+  def self.rm: (*untyped args, **untyped options) -> untyped
+
+  def self.rm_f: (*untyped args, **untyped options) -> untyped
+
+  def self.rm_r: (*untyped args, **untyped options) -> untyped
+
+  def self.rm_rf: (*untyped args, **untyped options) -> untyped
+
+  def self.rmdir: (*untyped args, **untyped options) -> untyped
+
+  def self.rmtree: (*untyped args, **untyped options) -> untyped
+
+  def self.safe_unlink: (*untyped args, **untyped options) -> untyped
+
+  def self.symlink: (*untyped args, **untyped options) -> untyped
+
+  def self.touch: (*untyped args, **untyped options) -> untyped
+
+  def self.uptodate?: (*untyped _) -> untyped
+end
+
+class Bundler::FileUtils::Entry_
+  include ::Bundler::FileUtils::StreamUtils_
+
+  def blockdev?: () -> untyped
+
+  def chardev?: () -> untyped
+
+  def chmod: (untyped mode) -> untyped
+
+  def chown: (untyped uid, untyped gid) -> untyped
+
+  def copy: (untyped dest) -> untyped
+
+  def copy_file: (untyped dest) -> untyped
+
+  def copy_metadata: (untyped path) -> untyped
+
+  def dereference?: () -> untyped
+
+  def directory?: () -> untyped
+
+  def door?: () -> untyped
+
+  def entries: () -> untyped
+
+  def exist?: () -> untyped
+
+  def file?: () -> untyped
+
+  def initialize: (untyped a, ?untyped b, ?untyped deref) -> void
+
+  def inspect: () -> untyped
+
+  def lstat: () -> untyped
+
+  def lstat!: () -> untyped
+
+  def path: () -> untyped
+
+  def pipe?: () -> untyped
+
+  def platform_support: () -> untyped
+
+  def postorder_traverse: () -> untyped
+
+  def prefix: () -> untyped
+
+  def preorder_traverse: () -> untyped
+
+  def rel: () -> untyped
+
+  def remove: () -> untyped
+
+  def remove_dir1: () -> untyped
+
+  def remove_file: () -> untyped
+
+  def socket?: () -> untyped
+
+  def stat: () -> untyped
+
+  def stat!: () -> untyped
+
+  def symlink?: () -> untyped
+
+  def traverse: () -> untyped
+
+  def wrap_traverse: (untyped pre, untyped post) -> untyped
+end
+
+Bundler::FileUtils::Entry_::DIRECTORY_TERM: untyped
+
+Bundler::FileUtils::Entry_::SYSCASE: untyped
+
+Bundler::FileUtils::Entry_::S_IF_DOOR: untyped
+
+module Bundler::FileUtils::LowMethods
+end
+
+# This module has all methods of
+# [`Bundler::FileUtils`](https://docs.ruby-lang.org/en/2.7.0/Bundler/FileUtils.html)
+# module, but never changes files/directories.  This equates to passing the
+# `:noop` flag to methods in
+# [`Bundler::FileUtils`](https://docs.ruby-lang.org/en/2.7.0/Bundler/FileUtils.html).
+module Bundler::FileUtils::NoWrite
+  include ::Bundler::FileUtils::LowMethods
+
+  include ::Bundler::FileUtils
+
+  include ::Bundler::FileUtils::StreamUtils_
+
+  extend ::Bundler::FileUtils::NoWrite
+
+  extend ::Bundler::FileUtils::LowMethods
+
+  extend ::Bundler::FileUtils
+
+  extend ::Bundler::FileUtils::StreamUtils_
+
+  def self.cd: (*untyped _) -> untyped
+
+  def self.chdir: (*untyped _) -> untyped
+
+  def self.chmod: (*untyped args, **untyped options) -> untyped
+
+  def self.chmod_R: (*untyped args, **untyped options) -> untyped
+
+  def self.chown: (*untyped args, **untyped options) -> untyped
+
+  def self.chown_R: (*untyped args, **untyped options) -> untyped
+
+  def self.cmp: (*untyped _) -> untyped
+
+  def self.compare_file: (*untyped _) -> untyped
+
+  def self.compare_stream: (*untyped _) -> untyped
+
+  def self.copy: (*untyped args, **untyped options) -> untyped
+
+  def self.copy_entry: (*untyped _) -> untyped
+
+  def self.copy_file: (*untyped _) -> untyped
+
+  def self.copy_stream: (*untyped _) -> untyped
+
+  def self.cp: (*untyped args, **untyped options) -> untyped
+
+  def self.cp_r: (*untyped args, **untyped options) -> untyped
+
+  def self.getwd: (*untyped _) -> untyped
+
+  def self.identical?: (*untyped _) -> untyped
+
+  def self.install: (*untyped args, **untyped options) -> untyped
+
+  def self.link: (*untyped args, **untyped options) -> untyped
+
+  def self.ln: (*untyped args, **untyped options) -> untyped
+
+  def self.ln_s: (*untyped args, **untyped options) -> untyped
+
+  def self.ln_sf: (*untyped args, **untyped options) -> untyped
+
+  def self.makedirs: (*untyped args, **untyped options) -> untyped
+
+  def self.mkdir: (*untyped args, **untyped options) -> untyped
+
+  def self.mkdir_p: (*untyped args, **untyped options) -> untyped
+
+  def self.mkpath: (*untyped args, **untyped options) -> untyped
+
+  def self.move: (*untyped args, **untyped options) -> untyped
+
+  def self.mv: (*untyped args, **untyped options) -> untyped
+
+  def self.pwd: (*untyped _) -> untyped
+
+  def self.remove: (*untyped args, **untyped options) -> untyped
+
+  def self.remove_dir: (*untyped _) -> untyped
+
+  def self.remove_entry: (*untyped _) -> untyped
+
+  def self.remove_entry_secure: (*untyped _) -> untyped
+
+  def self.remove_file: (*untyped _) -> untyped
+
+  def self.rm: (*untyped args, **untyped options) -> untyped
+
+  def self.rm_f: (*untyped args, **untyped options) -> untyped
+
+  def self.rm_r: (*untyped args, **untyped options) -> untyped
+
+  def self.rm_rf: (*untyped args, **untyped options) -> untyped
+
+  def self.rmdir: (*untyped args, **untyped options) -> untyped
+
+  def self.rmtree: (*untyped args, **untyped options) -> untyped
+
+  def self.safe_unlink: (*untyped args, **untyped options) -> untyped
+
+  def self.symlink: (*untyped args, **untyped options) -> untyped
+
+  def self.touch: (*untyped args, **untyped options) -> untyped
+
+  def self.uptodate?: (*untyped _) -> untyped
+end
+
+module Bundler::FileUtils::StreamUtils_
+end
+
+# This module has all methods of
+# [`Bundler::FileUtils`](https://docs.ruby-lang.org/en/2.7.0/Bundler/FileUtils.html)
+# module, but it outputs messages before acting. This equates to passing the
+# `:verbose` flag to methods in
+# [`Bundler::FileUtils`](https://docs.ruby-lang.org/en/2.7.0/Bundler/FileUtils.html).
+module Bundler::FileUtils::Verbose
+  include ::Bundler::FileUtils
+
+  include ::Bundler::FileUtils::StreamUtils_
+
+  extend ::Bundler::FileUtils::Verbose
+
+  extend ::Bundler::FileUtils
+
+  extend ::Bundler::FileUtils::StreamUtils_
+
+  def self.cd: (*untyped args, **untyped options) -> untyped
+
+  def self.chdir: (*untyped args, **untyped options) -> untyped
+
+  def self.chmod: (*untyped args, **untyped options) -> untyped
+
+  def self.chmod_R: (*untyped args, **untyped options) -> untyped
+
+  def self.chown: (*untyped args, **untyped options) -> untyped
+
+  def self.chown_R: (*untyped args, **untyped options) -> untyped
+
+  def self.cmp: (untyped a, untyped b) -> untyped
+
+  def self.compare_file: (untyped a, untyped b) -> untyped
+
+  def self.compare_stream: (untyped a, untyped b) -> untyped
+
+  def self.copy: (*untyped args, **untyped options) -> untyped
+
+  def self.copy_entry: (untyped src, untyped dest, ?untyped preserve, ?untyped dereference_root, ?untyped remove_destination) -> untyped
+
+  def self.copy_file: (untyped src, untyped dest, ?untyped preserve, ?untyped dereference) -> untyped
+
+  def self.copy_stream: (untyped src, untyped dest) -> untyped
+
+  def self.cp: (*untyped args, **untyped options) -> untyped
+
+  def self.cp_r: (*untyped args, **untyped options) -> untyped
+
+  def self.getwd: () -> untyped
+
+  def self.identical?: (untyped a, untyped b) -> untyped
+
+  def self.install: (*untyped args, **untyped options) -> untyped
+
+  def self.link: (*untyped args, **untyped options) -> untyped
+
+  def self.ln: (*untyped args, **untyped options) -> untyped
+
+  def self.ln_s: (*untyped args, **untyped options) -> untyped
+
+  def self.ln_sf: (*untyped args, **untyped options) -> untyped
+
+  def self.makedirs: (*untyped args, **untyped options) -> untyped
+
+  def self.mkdir: (*untyped args, **untyped options) -> untyped
+
+  def self.mkdir_p: (*untyped args, **untyped options) -> untyped
+
+  def self.mkpath: (*untyped args, **untyped options) -> untyped
+
+  def self.move: (*untyped args, **untyped options) -> untyped
+
+  def self.mv: (*untyped args, **untyped options) -> untyped
+
+  def self.pwd: () -> untyped
+
+  def self.remove: (*untyped args, **untyped options) -> untyped
+
+  def self.remove_dir: (untyped path, ?untyped force) -> untyped
+
+  def self.remove_entry: (untyped path, ?untyped force) -> untyped
+
+  def self.remove_entry_secure: (untyped path, ?untyped force) -> untyped
+
+  def self.remove_file: (untyped path, ?untyped force) -> untyped
+
+  def self.rm: (*untyped args, **untyped options) -> untyped
+
+  def self.rm_f: (*untyped args, **untyped options) -> untyped
+
+  def self.rm_r: (*untyped args, **untyped options) -> untyped
+
+  def self.rm_rf: (*untyped args, **untyped options) -> untyped
+
+  def self.rmdir: (*untyped args, **untyped options) -> untyped
+
+  def self.rmtree: (*untyped args, **untyped options) -> untyped
+
+  def self.safe_unlink: (*untyped args, **untyped options) -> untyped
+
+  def self.symlink: (*untyped args, **untyped options) -> untyped
+
+  def self.touch: (*untyped args, **untyped options) -> untyped
+
+  def self.uptodate?: (untyped new, untyped old_list) -> untyped
+end
+
+class Bundler::GemHelper
+  def allowed_push_host: () -> untyped
+
+  def already_tagged?: () -> untyped
+
+  def base: () -> untyped
+
+  def build_checksum: (?untyped built_gem_path) -> untyped
+
+  def build_gem: () -> untyped
+
+  def built_gem_path: () -> untyped
+
+  def clean?: () -> untyped
+
+  def committed?: () -> untyped
+
+  def current_branch: () -> untyped
+
+  def default_remote: () -> untyped
+
+  def gem_command: () -> untyped
+
+  def gem_key: () -> untyped
+
+  def gem_push?: () -> untyped
+
+  def gem_push_host: () -> untyped
+
+  def gemspec: () -> untyped
+
+  def git_push: (?untyped remote) -> untyped
+
+  def guard_clean: () -> untyped
+
+  def initialize: (?untyped base, ?untyped name) -> void
+
+  def install: () -> untyped
+
+  def install_gem: (?untyped built_gem_path, ?untyped local) -> untyped
+
+  def name: () -> untyped
+
+  def rubygem_push: (untyped path) -> untyped
+
+  def sh: (untyped cmd) { () -> untyped } -> untyped
+
+  def sh_with_input: (untyped cmd) -> untyped
+
+  def sh_with_status: (untyped cmd) { () -> untyped } -> untyped
+
+  def spec_path: () -> untyped
+
+  def tag_prefix=: (untyped tag_prefix) -> untyped
+
+  def tag_version: () -> untyped
+
+  def version: () -> untyped
+
+  def version_tag: () -> untyped
+
+  def self.instance: () -> untyped
+
+  def self.instance=: (untyped instance) -> untyped
+
+  def self.install_tasks: (?untyped opts) -> untyped
+
+  def self.tag_prefix=: (untyped tag_prefix) -> untyped
+
+  def self.gemspec: () { () -> untyped } -> untyped
+end
+
+module Bundler::GemHelpers
+  def self.generic: (untyped p) -> untyped
+
+  def self.generic_local_platform: () -> untyped
+
+  def self.platform_specificity_match: (untyped spec_platform, untyped user_platform) -> untyped
+
+  def self.select_best_platform_match: (untyped specs, untyped platform) -> untyped
+end
+
+Bundler::GemHelpers::GENERICS: untyped
+
+Bundler::GemHelpers::GENERIC_CACHE: untyped
+
+class Bundler::GemHelpers::PlatformMatch < Struct
+  def <=>: (untyped other) -> untyped
+
+  def cpu_match: () -> untyped
+
+  def cpu_match=: (untyped _) -> untyped
+
+  def os_match: () -> untyped
+
+  def os_match=: (untyped _) -> untyped
+
+  def platform_version_match: () -> untyped
+
+  def platform_version_match=: (untyped _) -> untyped
+
+  def self.[]: (*untyped _) -> untyped
+
+  def self.cpu_match: (untyped spec_platform, untyped user_platform) -> untyped
+
+  def self.members: () -> untyped
+
+  def self.new: (*untyped _) -> untyped
+
+  def self.os_match: (untyped spec_platform, untyped user_platform) -> untyped
+
+  def self.platform_version_match: (untyped spec_platform, untyped user_platform) -> untyped
+end
+
+Bundler::GemHelpers::PlatformMatch::Elem: untyped
+
+Bundler::GemHelpers::PlatformMatch::EXACT_MATCH: untyped
+
+Bundler::GemHelpers::PlatformMatch::WORST_MATCH: untyped
+
+class Bundler::GemNotFound < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+class Bundler::GemRequireError < Bundler::BundlerError
+  def initialize: (untyped orig_exception, untyped msg) -> void
+
+  def orig_exception: () -> untyped
+
+  def status_code: () -> untyped
+end
+
+class Bundler::GemfileError < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+class Bundler::GemfileEvalError < Bundler::GemfileError
+end
+
+class Bundler::GemfileLockNotFound < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+class Bundler::GemfileNotFound < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+class Bundler::GemspecError < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+class Bundler::GenericSystemCallError < Bundler::BundlerError
+  def initialize: (untyped underlying_error, untyped message) -> void
+
+  def status_code: () -> untyped
+
+  def underlying_error: () -> untyped
+end
+
+class Bundler::GitError < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+class Bundler::HTTPError < Bundler::BundlerError
+  def filter_uri: (untyped uri) -> untyped
+
+  def status_code: () -> untyped
+end
+
+# Handles all the fetching with the rubygems server
+class Bundler::Fetcher
+end
+
+# This error is raised if HTTP authentication is required, but not provided.
+class Bundler::Fetcher::AuthenticationRequiredError < Bundler::HTTPError
+end
+
+# This error is raised if HTTP authentication is provided, but incorrect.
+class Bundler::Fetcher::BadAuthenticationError < Bundler::HTTPError
+end
+
+# This is the error raised if
+# [`OpenSSL`](https://docs.ruby-lang.org/en/2.7.0/OpenSSL.html) fails the cert
+# verification
+class Bundler::Fetcher::CertificateFailureError < Bundler::HTTPError
+end
+
+# This error is raised if the API returns a 413 (only printed in verbose)
+class Bundler::Fetcher::FallbackError < Bundler::HTTPError
+end
+
+# This error is raised when it looks like the network is down
+class Bundler::Fetcher::NetworkDownError < Bundler::HTTPError
+end
+
+# This is the error raised when a source is HTTPS and
+# [`OpenSSL`](https://docs.ruby-lang.org/en/2.7.0/OpenSSL.html) didn't load
+class Bundler::Fetcher::SSLError < Bundler::HTTPError
+end
+
+class Bundler::Index[out Elem]
+  include ::Enumerable
+
+  def <<: (untyped spec) -> untyped
+
+  def ==: (untyped other) -> untyped
+
+  def []: (untyped query, ?untyped base) -> untyped
+
+  def add_source: (untyped index) -> untyped
+
+  def all_specs: () -> untyped
+
+  def dependencies_eql?: (untyped spec, untyped other_spec) -> untyped
+
+  def dependency_names: () -> untyped
+
+  def each: () { () -> untyped } -> untyped
+
+  def empty?: () -> untyped
+
+  def initialize: () -> void
+
+  def inspect: () -> untyped
+
+  def local_search: (untyped query, ?untyped base) -> untyped
+
+  def search: (untyped query, ?untyped base) -> untyped
+
+  def search_all: (untyped name) -> untyped
+
+  def size: () -> untyped
+
+  def sort_specs: (untyped specs) -> untyped
+
+  def sources: () -> untyped
+
+  def spec_names: () -> untyped
+
+  def specs: () -> untyped
+
+  # returns a list of the dependencies
+  def unmet_dependency_names: () -> untyped
+
+  def unsorted_search: (untyped query, untyped base) -> untyped
+
+  def use: (untyped other, ?untyped override_dupes) -> untyped
+
+  def self.build: () -> untyped
+
+  def self.sort_specs: (untyped specs) -> untyped
+end
+
+Bundler::Index::EMPTY_SEARCH: untyped
+
+Bundler::Index::NULL: untyped
+
+Bundler::Index::RUBY: untyped
+
+class Bundler::InstallError < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+class Bundler::InstallHookError < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+class Bundler::InvalidOption < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+class Bundler::LazySpecification
+  include ::Bundler::MatchPlatform
+
+  include ::Bundler::GemHelpers
+
+  def ==: (untyped other) -> untyped
+
+  def __materialize__: () -> untyped
+
+  def dependencies: () -> untyped
+
+  def full_name: () -> untyped
+
+  def git_version: () -> untyped
+
+  def identifier: () -> untyped
+
+  def initialize: (untyped name, untyped version, untyped platform, ?untyped source) -> void
+
+  def name: () -> String
+
+  def platform: () -> untyped
+
+  def remote: () -> untyped
+
+  def remote=: (untyped remote) -> untyped
+
+  def respond_to?: (*untyped args) -> untyped
+
+  def satisfies?: (untyped dependency) -> untyped
+
+  def source: () -> untyped
+
+  def source=: (untyped source) -> untyped
+
+  def to_lock: () -> untyped
+
+  def to_s: () -> untyped
+
+  def version: () -> String
+end
+
+class Bundler::LazySpecification::Identifier < Struct
+  include ::Comparable
+
+  extend ::T::Generic
+
+  def <=>: (untyped other) -> untyped
+
+  def dependencies: () -> untyped
+
+  def dependencies=: (untyped _) -> untyped
+
+  def name: () -> untyped
+
+  def name=: (untyped _) -> untyped
+
+  def platform: () -> untyped
+
+  def platform=: (untyped _) -> untyped
+
+  def platform_string: () -> untyped
+
+  def source: () -> untyped
+
+  def source=: (untyped _) -> untyped
+
+  def version: () -> untyped
+
+  def version=: (untyped _) -> untyped
+
+  def self.[]: (*untyped _) -> untyped
+
+  def self.members: () -> untyped
+
+  def self.new: (*untyped _) -> untyped
+end
+
+Bundler::LazySpecification::Identifier::Elem: untyped
+
+class Bundler::LockfileError < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+class Bundler::LockfileParser
+  def bundler_version: () -> untyped
+
+  def dependencies: () -> Hash[String, Bundler::Dependency]
+
+  def initialize: (untyped lockfile) -> void
+
+  def platforms: () -> untyped
+
+  def ruby_version: () -> untyped
+
+  def sources: () -> untyped
+
+  def specs: () -> ::Array[::Bundler::LazySpecification]
+
+  def warn_for_outdated_bundler_version: () -> untyped
+
+  def self.sections_in_lockfile: (untyped lockfile_contents) -> untyped
+
+  def self.sections_to_ignore: (?untyped base_version) -> untyped
+
+  def self.unknown_sections_in_lockfile: (untyped lockfile_contents) -> untyped
+end
+
+Bundler::LockfileParser::BUNDLED: untyped
+
+Bundler::LockfileParser::DEPENDENCIES: untyped
+
+Bundler::LockfileParser::ENVIRONMENT_VERSION_SECTIONS: untyped
+
+Bundler::LockfileParser::GEM: untyped
+
+Bundler::LockfileParser::GIT: untyped
+
+Bundler::LockfileParser::KNOWN_SECTIONS: untyped
+
+Bundler::LockfileParser::NAME_VERSION: untyped
+
+Bundler::LockfileParser::OPTIONS: untyped
+
+Bundler::LockfileParser::PATH: untyped
+
+Bundler::LockfileParser::PLATFORMS: untyped
+
+Bundler::LockfileParser::PLUGIN: untyped
+
+Bundler::LockfileParser::RUBY: untyped
+
+Bundler::LockfileParser::SECTIONS_BY_VERSION_INTRODUCED: untyped
+
+Bundler::LockfileParser::SOURCE: untyped
+
+Bundler::LockfileParser::SPECS: untyped
+
+Bundler::LockfileParser::TYPES: untyped
+
+class Bundler::MarshalError < StandardError
+end
+
+module Bundler::MatchPlatform
+  include ::Bundler::GemHelpers
+
+  def match_platform: (untyped p) -> untyped
+
+  def self.platforms_match?: (untyped gemspec_platform, untyped local_platform) -> untyped
+end
+
+# [`Bundler::Molinillo`](https://docs.ruby-lang.org/en/2.7.0/Bundler/Molinillo.html)
+# is a generic dependency resolution algorithm.
+module Bundler::Molinillo
+end
+
+Bundler::Molinillo::VERSION: untyped
+
+# An error caused by attempting to fulfil a dependency that was circular
+#
+# @note This exception will be thrown iff a {Vertex} is added to a
+#
+# ```
+# {DependencyGraph} that has a {DependencyGraph::Vertex#path_to?} an
+# existing {DependencyGraph::Vertex}
+# ```
+class Bundler::Molinillo::CircularDependencyError < Bundler::Molinillo::ResolverError
+  # [`Set`](https://docs.ruby-lang.org/en/2.7.0/Set.html)<Object>
+  # :   the dependencies responsible for causing the error
+  def dependencies: () -> untyped
+
+  def initialize: (untyped vertices) -> void
+end
+
+# Hacks needed for old Ruby versions.
+module Bundler::Molinillo::Compatibility
+  def self.flat_map: (untyped enum) { () -> untyped } -> untyped
+end
+
+# @!visibility private
+module Bundler::Molinillo::Delegates
+end
+
+# [`Delegates`](https://docs.ruby-lang.org/en/2.7.0/Bundler/Molinillo/Delegates.html)
+# all {Bundler::Molinillo::ResolutionState} methods to a `#state` property.
+module Bundler::Molinillo::Delegates::ResolutionState
+  # (see Bundler::Molinillo::ResolutionState#activated)
+  def activated: () -> untyped
+
+  # (see Bundler::Molinillo::ResolutionState#conflicts)
+  def conflicts: () -> untyped
+
+  # (see Bundler::Molinillo::ResolutionState#depth)
+  def depth: () -> untyped
+
+  # (see Bundler::Molinillo::ResolutionState#name)
+  def name: () -> untyped
+
+  # (see Bundler::Molinillo::ResolutionState#possibilities)
+  def possibilities: () -> untyped
+
+  # (see Bundler::Molinillo::ResolutionState#requirement)
+  def requirement: () -> untyped
+
+  # (see Bundler::Molinillo::ResolutionState#requirements)
+  def requirements: () -> untyped
+
+  # (see Bundler::Molinillo::ResolutionState#unused\_unwind\_options)
+  def unused_unwind_options: () -> untyped
+end
+
+# [`Delegates`](https://docs.ruby-lang.org/en/2.7.0/Bundler/Molinillo/Delegates.html)
+# all {Bundler::Molinillo::SpecificationProvider} methods to a
+# `#specification\_provider` property.
+module Bundler::Molinillo::Delegates::SpecificationProvider
+  def allow_missing?: (untyped dependency) -> untyped
+
+  def dependencies_for: (untyped specification) -> untyped
+
+  def name_for: (untyped dependency) -> untyped
+
+  # (see
+  # [`Bundler::Molinillo::SpecificationProvider#name_for_explicit_dependency_source`](https://docs.ruby-lang.org/en/2.7.0/Bundler/Molinillo/SpecificationProvider.html#method-i-name_for_explicit_dependency_source))
+  def name_for_explicit_dependency_source: () -> untyped
+
+  # (see
+  # [`Bundler::Molinillo::SpecificationProvider#name_for_locking_dependency_source`](https://docs.ruby-lang.org/en/2.7.0/Bundler/Molinillo/SpecificationProvider.html#method-i-name_for_locking_dependency_source))
+  def name_for_locking_dependency_source: () -> untyped
+
+  def requirement_satisfied_by?: (untyped requirement, untyped activated, untyped spec) -> untyped
+
+  def search_for: (untyped dependency) -> untyped
+
+  def sort_dependencies: (untyped dependencies, untyped activated, untyped conflicts) -> untyped
+end
+
+# A directed acyclic graph that is tuned to hold named dependencies
+class Bundler::Molinillo::DependencyGraph[out Elem]
+  include ::TSort
+
+  include ::Enumerable
+
+  def ==: (untyped other) -> untyped
+
+  def add_child_vertex: (untyped name, untyped payload, untyped parent_names, untyped requirement) -> untyped
+
+  def add_edge: (untyped origin, untyped destination, untyped requirement) -> untyped
+
+  def add_vertex: (untyped name, untyped payload, ?untyped root) -> untyped
+
+  def delete_edge: (untyped edge) -> untyped
+
+  def detach_vertex_named: (untyped name) -> untyped
+
+  def each: () { () -> untyped } -> untyped
+
+  def initialize: () -> void
+
+  # @return [String] a string suitable for debugging
+  def inspect: () -> untyped
+
+  # @return [Log] the op log for this graph
+  def log: () -> untyped
+
+  def rewind_to: (untyped tag) -> untyped
+
+  def root_vertex_named: (untyped name) -> untyped
+
+  def set_payload: (untyped name, untyped payload) -> untyped
+
+  def tag: (untyped tag) -> untyped
+
+  def to_dot: (?untyped options) -> untyped
+
+  def tsort_each_child: (untyped vertex) { () -> untyped } -> untyped
+
+  # @!visibility private
+  #
+  # Alias for:
+  # [`each`](https://docs.ruby-lang.org/en/2.7.0/Bundler/Molinillo/DependencyGraph.html#method-i-each)
+  def tsort_each_node: () -> untyped
+
+  def vertex_named: (untyped name) -> untyped
+
+  # @return [{String => Vertex}] the vertices of the dependency graph, keyed
+  #
+  # ```
+  # by {Vertex#name}
+  # ```
+  def vertices: () -> untyped
+
+  def self.tsort: (untyped vertices) -> untyped
+end
+
+# An action that modifies a {DependencyGraph} that is reversible. @abstract
+class Bundler::Molinillo::DependencyGraph::Action
+  def down: (untyped graph) -> untyped
+
+  # @return [Action,Nil] The next action
+  def next: () -> untyped
+
+  def next=: (untyped _) -> untyped
+
+  # @return [Action,Nil] The previous action
+  def previous: () -> untyped
+
+  def previous=: (untyped previous) -> untyped
+
+  def up: (untyped graph) -> untyped
+
+  # @return [Symbol] The name of the action.
+  def self.action_name: () -> untyped
+end
+
+# @!visibility private (see
+# [`DependencyGraph#add_edge_no_circular`](https://docs.ruby-lang.org/en/2.7.0/Bundler/Molinillo/DependencyGraph.html#method-i-add_edge_no_circular))
+class Bundler::Molinillo::DependencyGraph::AddEdgeNoCircular < Bundler::Molinillo::DependencyGraph::Action
+  # @return [String] the name of the destination of the edge
+  def destination: () -> untyped
+
+  def down: (untyped graph) -> untyped
+
+  def initialize: (untyped origin, untyped destination, untyped requirement) -> void
+
+  def make_edge: (untyped graph) -> untyped
+
+  # @return [String] the name of the origin of the edge
+  def origin: () -> untyped
+
+  # @return [Object] the requirement that the edge represents
+  def requirement: () -> untyped
+
+  def up: (untyped graph) -> untyped
+
+  # (see Action.action\_name)
+  def self.action_name: () -> untyped
+end
+
+class Bundler::Molinillo::DependencyGraph::AddVertex < Bundler::Molinillo::DependencyGraph::Action
+  def down: (untyped graph) -> untyped
+
+  def initialize: (untyped name, untyped payload, untyped root) -> void
+
+  def name: () -> untyped
+
+  def payload: () -> untyped
+
+  def root: () -> untyped
+
+  def up: (untyped graph) -> untyped
+
+  def self.action_name: () -> untyped
+end
+
+# @!visibility private (see
+# [`DependencyGraph#delete_edge`](https://docs.ruby-lang.org/en/2.7.0/Bundler/Molinillo/DependencyGraph.html#method-i-delete_edge))
+class Bundler::Molinillo::DependencyGraph::DeleteEdge < Bundler::Molinillo::DependencyGraph::Action
+  # @return [String] the name of the destination of the edge
+  def destination_name: () -> untyped
+
+  def down: (untyped graph) -> untyped
+
+  def initialize: (untyped origin_name, untyped destination_name, untyped requirement) -> void
+
+  def make_edge: (untyped graph) -> untyped
+
+  # @return [String] the name of the origin of the edge
+  def origin_name: () -> untyped
+
+  # @return [Object] the requirement that the edge represents
+  def requirement: () -> untyped
+
+  def up: (untyped graph) -> untyped
+
+  # (see Action.action\_name)
+  def self.action_name: () -> untyped
+end
+
+# @!visibility private @see
+# [`DependencyGraph#detach_vertex_named`](https://docs.ruby-lang.org/en/2.7.0/Bundler/Molinillo/DependencyGraph.html#method-i-detach_vertex_named)
+class Bundler::Molinillo::DependencyGraph::DetachVertexNamed < Bundler::Molinillo::DependencyGraph::Action
+  def down: (untyped graph) -> untyped
+
+  def initialize: (untyped name) -> void
+
+  # @return [String] the name of the vertex to detach
+  def name: () -> untyped
+
+  def up: (untyped graph) -> untyped
+
+  # (see Action#name)
+  def self.action_name: () -> untyped
+end
+
+# A directed edge of a {DependencyGraph} @attr [Vertex] origin The origin of the
+# directed edge @attr [Vertex] destination The destination of the directed edge
+# @attr [Object] requirement The requirement the directed edge represents
+class Bundler::Molinillo::DependencyGraph::Edge < Struct
+  def destination: () -> untyped
+
+  def destination=: (untyped _) -> untyped
+
+  def origin: () -> untyped
+
+  def origin=: (untyped _) -> untyped
+
+  def requirement: () -> untyped
+
+  def requirement=: (untyped _) -> untyped
+
+  def self.[]: (*untyped _) -> untyped
+
+  def self.members: () -> untyped
+
+  def self.new: (*untyped _) -> untyped
+end
+
+Bundler::Molinillo::DependencyGraph::Edge::Elem: untyped
+
+# A log for dependency graph actions
+class Bundler::Molinillo::DependencyGraph::Log
+  extend ::Enumerable
+
+  def add_edge_no_circular: (untyped graph, untyped origin, untyped destination, untyped requirement) -> untyped
+
+  def add_vertex: (untyped graph, untyped name, untyped payload, untyped root) -> untyped
+
+  def delete_edge: (untyped graph, untyped origin_name, untyped destination_name, untyped requirement) -> untyped
+
+  def detach_vertex_named: (untyped graph, untyped name) -> untyped
+
+  def each: () { () -> untyped } -> untyped
+
+  def initialize: () -> void
+
+  def pop!: (untyped graph) -> untyped
+
+  # @!visibility private Enumerates each action in the log in reverse order
+  # @yield [Action]
+  def reverse_each: () -> untyped
+
+  def rewind_to: (untyped graph, untyped tag) -> untyped
+
+  def set_payload: (untyped graph, untyped name, untyped payload) -> untyped
+
+  def tag: (untyped graph, untyped tag) -> untyped
+end
+
+Bundler::Molinillo::DependencyGraph::Log::Elem: untyped
+
+class Bundler::Molinillo::DependencyGraph::SetPayload < Bundler::Molinillo::DependencyGraph::Action
+  def down: (untyped graph) -> untyped
+
+  def initialize: (untyped name, untyped payload) -> void
+
+  def name: () -> untyped
+
+  def payload: () -> untyped
+
+  def up: (untyped graph) -> untyped
+
+  def self.action_name: () -> untyped
+end
+
+# @!visibility private @see
+# [`DependencyGraph#tag`](https://docs.ruby-lang.org/en/2.7.0/Bundler/Molinillo/DependencyGraph.html#method-i-tag)
+class Bundler::Molinillo::DependencyGraph::Tag < Bundler::Molinillo::DependencyGraph::Action
+  def down: (untyped _graph) -> untyped
+
+  def initialize: (untyped tag) -> void
+
+  # @return [Object] An opaque tag
+  def tag: () -> untyped
+
+  def up: (untyped _graph) -> untyped
+
+  # (see Action.action\_name)
+  def self.action_name: () -> untyped
+end
+
+# A vertex in a {DependencyGraph} that encapsulates a {#name} and a {#payload}
+class Bundler::Molinillo::DependencyGraph::Vertex
+  def ==: (untyped other) -> untyped
+
+  def _path_to?: (untyped other, ?untyped visited) -> untyped
+
+  def ancestor?: (untyped other) -> untyped
+
+  def descendent?: (untyped other) -> untyped
+
+  def eql?: (untyped other) -> untyped
+
+  # @return [Array<Object>] the explicit requirements that required
+  #
+  # ```ruby
+  # this vertex
+  # ```
+  def explicit_requirements: () -> untyped
+
+  # @return [Fixnum] a hash for the vertex based upon its {#name}
+  def hash: () -> untyped
+
+  # @return [Array<Edge>] the edges of {#graph} that have `self` as their
+  #
+  # ```
+  # {Edge#destination}
+  # ```
+  def incoming_edges: () -> untyped
+
+  def incoming_edges=: (untyped incoming_edges) -> untyped
+
+  def initialize: (untyped name, untyped payload) -> void
+
+  # @return [String] a string suitable for debugging
+  def inspect: () -> untyped
+
+  def is_reachable_from?: (untyped other) -> untyped
+
+  # @return [String] the name of the vertex
+  def name: () -> untyped
+
+  def name=: (untyped name) -> untyped
+
+  # @return [Array<Edge>] the edges of {#graph} that have `self` as their
+  #
+  # ```
+  # {Edge#origin}
+  # ```
+  def outgoing_edges: () -> untyped
+
+  def outgoing_edges=: (untyped outgoing_edges) -> untyped
+
+  def path_to?: (untyped other) -> untyped
+
+  # @return [Object] the payload the vertex holds
+  def payload: () -> untyped
+
+  def payload=: (untyped payload) -> untyped
+
+  # @return [Array<Vertex>] the vertices of {#graph} that have an edge with
+  #
+  # ```
+  # `self` as their {Edge#destination}
+  # ```
+  def predecessors: () -> untyped
+
+  # @return [Set<Vertex>] the vertices of {#graph} where `self` is a
+  #
+  # ```
+  # {#descendent?}
+  # ```
+  def recursive_predecessors: () -> untyped
+
+  # @return [Set<Vertex>] the vertices of {#graph} where `self` is an
+  #
+  # ```
+  # {#ancestor?}
+  # ```
+  def recursive_successors: () -> untyped
+
+  # @return [Array<Object>] all of the requirements that required
+  #
+  # ```ruby
+  # this vertex
+  # ```
+  def requirements: () -> untyped
+
+  # @return [Boolean] whether the vertex is considered a root vertex
+  def root: () -> untyped
+
+  def root=: (untyped root) -> untyped
+
+  # @return [Boolean] whether the vertex is considered a root vertex
+  def root?: () -> untyped
+
+  def shallow_eql?: (untyped other) -> untyped
+
+  # @return [Array<Vertex>] the vertices of {#graph} that have an edge with
+  #
+  # ```
+  # `self` as their {Edge#origin}
+  # ```
+  def successors: () -> untyped
+end
+
+# A state that encapsulates a set of {#requirements} with an {Array} of
+# possibilities
+class Bundler::Molinillo::DependencyState < Bundler::Molinillo::ResolutionState
+  # Removes a possibility from `self` @return [PossibilityState] a state with a
+  # single possibility,
+  #
+  # ```ruby
+  # the possibility that was removed from `self`
+  # ```
+  def pop_possibility_state: () -> untyped
+end
+
+Bundler::Molinillo::DependencyState::Elem: untyped
+
+# An error caused by searching for a dependency that is completely unknown, i.e.
+# has no versions available whatsoever.
+class Bundler::Molinillo::NoSuchDependencyError < Bundler::Molinillo::ResolverError
+  # @return [Object] the dependency that could not be found
+  def dependency: () -> untyped
+
+  def dependency=: (untyped dependency) -> untyped
+
+  def initialize: (untyped dependency, ?untyped required_by) -> void
+
+  # The error message for the missing dependency, including the specifications
+  # that had this dependency.
+  def message: () -> untyped
+
+  # @return [Array<Object>] the specifications that depended upon {#dependency}
+  def required_by: () -> untyped
+
+  def required_by=: (untyped required_by) -> untyped
+end
+
+# A state that encapsulates a single possibility to fulfill the given
+# {#requirement}
+class Bundler::Molinillo::PossibilityState < Bundler::Molinillo::ResolutionState
+end
+
+Bundler::Molinillo::PossibilityState::Elem: untyped
+
+class Bundler::Molinillo::ResolutionState < Struct
+  def activated: () -> untyped
+
+  def activated=: (untyped _) -> untyped
+
+  def conflicts: () -> untyped
+
+  def conflicts=: (untyped _) -> untyped
+
+  def depth: () -> untyped
+
+  def depth=: (untyped _) -> untyped
+
+  def name: () -> untyped
+
+  def name=: (untyped _) -> untyped
+
+  def possibilities: () -> untyped
+
+  def possibilities=: (untyped _) -> untyped
+
+  def requirement: () -> untyped
+
+  def requirement=: (untyped _) -> untyped
+
+  def requirements: () -> untyped
+
+  def requirements=: (untyped _) -> untyped
+
+  def unused_unwind_options: () -> untyped
+
+  def unused_unwind_options=: (untyped _) -> untyped
+
+  def self.[]: (*untyped _) -> untyped
+
+  # Returns an empty resolution state @return [ResolutionState] an empty state
+  def self.empty: () -> untyped
+
+  def self.members: () -> untyped
+
+  def self.new: (*untyped _) -> untyped
+end
+
+Bundler::Molinillo::ResolutionState::Elem: untyped
+
+# This class encapsulates a dependency resolver. The resolver is responsible for
+# determining which set of dependencies to activate, with feedback from the
+# {#specification\_provider}
+class Bundler::Molinillo::Resolver
+  def initialize: (untyped specification_provider, untyped resolver_ui) -> void
+
+  def resolve: (untyped requested, ?untyped base) -> untyped
+
+  # @return [UI] the UI module used to communicate back to the user
+  #
+  # ```ruby
+  # during the resolution process
+  # ```
+  def resolver_ui: () -> untyped
+
+  # @return [SpecificationProvider] the specification provider used
+  #
+  # ```
+  # in the resolution process
+  # ```
+  def specification_provider: () -> untyped
+end
+
+# A specific resolution from a given {Resolver}
+class Bundler::Molinillo::Resolver::Resolution
+  include ::Bundler::Molinillo::Delegates::SpecificationProvider
+
+  include ::Bundler::Molinillo::Delegates::ResolutionState
+
+  # @return [DependencyGraph] the base dependency graph to which
+  #
+  # ```ruby
+  # dependencies should be 'locked'
+  # ```
+  def base: () -> untyped
+
+  def initialize: (untyped specification_provider, untyped resolver_ui, untyped requested, untyped base) -> void
+
+  def iteration_rate=: (untyped iteration_rate) -> untyped
+
+  # @return [Array] the dependencies that were explicitly required
+  def original_requested: () -> untyped
+
+  # Resolves the {#original\_requested} dependencies into a full dependency
+  #
+  # ```ruby
+  # graph
+  # ```
+  #
+  # @raise [ResolverError] if successful resolution is impossible @return
+  # [DependencyGraph] the dependency graph of successfully resolved
+  #
+  # ```ruby
+  # dependencies
+  # ```
+  def resolve: () -> untyped
+
+  # @return [UI] the UI that knows how to communicate feedback about the
+  #
+  # ```ruby
+  # resolution process back to the user
+  # ```
+  def resolver_ui: () -> untyped
+
+  # @return [SpecificationProvider] the provider that knows about
+  #
+  # ```
+  # dependencies, requirements, specifications, versions, etc.
+  # ```
+  def specification_provider: () -> untyped
+
+  def started_at=: (untyped started_at) -> untyped
+
+  def states=: (untyped states) -> untyped
+end
+
+class Bundler::Molinillo::Resolver::Resolution::Conflict < Struct
+  def activated_by_name: () -> untyped
+
+  def activated_by_name=: (untyped _) -> untyped
+
+  def existing: () -> untyped
+
+  def existing=: (untyped _) -> untyped
+
+  def locked_requirement: () -> untyped
+
+  def locked_requirement=: (untyped _) -> untyped
+
+  # @return [Object] a spec that was unable to be activated due to a conflict
+  def possibility: () -> untyped
+
+  def possibility_set: () -> untyped
+
+  def possibility_set=: (untyped _) -> untyped
+
+  def requirement: () -> untyped
+
+  def requirement=: (untyped _) -> untyped
+
+  def requirement_trees: () -> untyped
+
+  def requirement_trees=: (untyped _) -> untyped
+
+  def requirements: () -> untyped
+
+  def requirements=: (untyped _) -> untyped
+
+  def underlying_error: () -> untyped
+
+  def underlying_error=: (untyped _) -> untyped
+
+  def self.[]: (*untyped _) -> untyped
+
+  def self.members: () -> untyped
+
+  def self.new: (*untyped _) -> untyped
+end
+
+Bundler::Molinillo::Resolver::Resolution::Conflict::Elem: untyped
+
+class Bundler::Molinillo::Resolver::Resolution::PossibilitySet < Struct
+  def dependencies: () -> untyped
+
+  def dependencies=: (untyped _) -> untyped
+
+  # @return [Object] most up-to-date dependency in the possibility set
+  def latest_version: () -> untyped
+
+  def possibilities: () -> untyped
+
+  def possibilities=: (untyped _) -> untyped
+
+  # [`String`](https://docs.ruby-lang.org/en/2.7.0/String.html) representation
+  # of the possibility set, for debugging
+  def to_s: () -> untyped
+
+  def self.[]: (*untyped _) -> untyped
+
+  def self.members: () -> untyped
+
+  def self.new: (*untyped _) -> untyped
+end
+
+Bundler::Molinillo::Resolver::Resolution::PossibilitySet::Elem: untyped
+
+class Bundler::Molinillo::Resolver::Resolution::UnwindDetails < Struct
+  include ::Comparable
+
+  def <=>: (untyped other) -> untyped
+
+  # @return [Array] array of all the requirements that led to the need for
+  #
+  # ```ruby
+  # this unwind
+  # ```
+  def all_requirements: () -> untyped
+
+  def conflicting_requirements: () -> untyped
+
+  def conflicting_requirements=: (untyped _) -> untyped
+
+  def requirement_tree: () -> untyped
+
+  def requirement_tree=: (untyped _) -> untyped
+
+  def requirement_trees: () -> untyped
+
+  def requirement_trees=: (untyped _) -> untyped
+
+  def requirements_unwound_to_instead: () -> untyped
+
+  def requirements_unwound_to_instead=: (untyped _) -> untyped
+
+  # @return [Integer] index of state requirement in reversed requirement tree
+  #
+  # ```ruby
+  # (the conflicting requirement itself will be at position 0)
+  # ```
+  def reversed_requirement_tree_index: () -> untyped
+
+  def state_index: () -> untyped
+
+  def state_index=: (untyped _) -> untyped
+
+  def state_requirement: () -> untyped
+
+  def state_requirement=: (untyped _) -> untyped
+
+  # @return [Array] array of sub-dependencies to avoid when choosing a
+  #
+  # ```
+  # new possibility for the state we've unwound to. Only relevant for
+  # non-primary unwinds
+  # ```
+  def sub_dependencies_to_avoid: () -> untyped
+
+  # @return [Boolean] where the requirement of the state we're unwinding
+  #
+  # ```
+  # to directly caused the conflict. Note: in this case, it is
+  # impossible for the state we're unwinding to to be a parent of
+  # any of the other conflicting requirements (or we would have
+  # circularity)
+  # ```
+  def unwinding_to_primary_requirement?: () -> untyped
+
+  def self.[]: (*untyped _) -> untyped
+
+  def self.members: () -> untyped
+
+  def self.new: (*untyped _) -> untyped
+end
+
+Bundler::Molinillo::Resolver::Resolution::UnwindDetails::Elem: untyped
+
+# An error that occurred during the resolution process
+class Bundler::Molinillo::ResolverError < StandardError
+end
+
+# Provides information about specifications and dependencies to the resolver,
+# allowing the {Resolver} class to remain generic while still providing power
+# and flexibility.
+#
+# This module contains the methods that users of
+# [`Bundler::Molinillo`](https://docs.ruby-lang.org/en/2.7.0/Bundler/Molinillo.html)
+# must to implement, using knowledge of their own model classes.
+module Bundler::Molinillo::SpecificationProvider
+  def allow_missing?: (untyped dependency) -> untyped
+
+  def dependencies_for: (untyped specification) -> untyped
+
+  def name_for: (untyped dependency) -> untyped
+
+  # @return [String] the name of the source of explicit dependencies, i.e.
+  #
+  # ```
+  # those passed to {Resolver#resolve} directly.
+  # ```
+  def name_for_explicit_dependency_source: () -> untyped
+
+  # @return [String] the name of the source of 'locked' dependencies, i.e.
+  #
+  # ```
+  # those passed to {Resolver#resolve} directly as the `base`
+  # ```
+  def name_for_locking_dependency_source: () -> untyped
+
+  def requirement_satisfied_by?: (untyped requirement, untyped activated, untyped spec) -> untyped
+
+  def search_for: (untyped dependency) -> untyped
+
+  def sort_dependencies: (untyped dependencies, untyped activated, untyped conflicts) -> untyped
+end
+
+# Conveys information about the resolution process to a user.
+module Bundler::Molinillo::UI
+  # Called after resolution ends (either successfully or with an error). By
+  # default, prints a newline.
+  #
+  # @return [void]
+  def after_resolution: () -> untyped
+
+  # Called before resolution begins.
+  #
+  # @return [void]
+  def before_resolution: () -> untyped
+
+  def debug: (?untyped depth) -> untyped
+
+  # Whether or not debug messages should be printed. By default, whether or not
+  # the `MOLINILLO\_DEBUG` environment variable is set.
+  #
+  # @return [Boolean]
+  def debug?: () -> untyped
+
+  # Called roughly every {#progress\_rate}, this method should convey progress
+  # to the user.
+  #
+  # @return [void]
+  def indicate_progress: () -> untyped
+
+  # The {IO} object that should be used to print output. `STDOUT`, by default.
+  #
+  # @return [IO]
+  def output: () -> untyped
+
+  # How often progress should be conveyed to the user via {#indicate\_progress},
+  # in seconds. A third of a second, by default.
+  #
+  # @return [Float]
+  def progress_rate: () -> untyped
+end
+
+# An error caused by conflicts in version
+class Bundler::Molinillo::VersionConflict < Bundler::Molinillo::ResolverError
+  include ::Bundler::Molinillo::Delegates::SpecificationProvider
+
+  # @return [{String => Resolution::Conflict}] the conflicts that caused
+  #
+  # ```ruby
+  # resolution to fail
+  # ```
+  def conflicts: () -> untyped
+
+  def initialize: (untyped conflicts, untyped specification_provider) -> void
+
+  def message_with_trees: (?untyped opts) -> untyped
+
+  # @return [SpecificationProvider] the specification provider used during
+  #
+  # ```ruby
+  # resolution
+  # ```
+  def specification_provider: () -> untyped
+end
+
+class Bundler::NoSpaceOnDeviceError < Bundler::PermissionError
+  def message: () -> untyped
+
+  def status_code: () -> untyped
+end
+
+class Bundler::OperationNotSupportedError < Bundler::PermissionError
+  def message: () -> untyped
+
+  def status_code: () -> untyped
+end
+
+class Bundler::PathError < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+class Bundler::PermissionError < Bundler::BundlerError
+  def action: () -> untyped
+
+  def initialize: (untyped path, ?untyped permission_type) -> void
+
+  def message: () -> untyped
+
+  def status_code: () -> untyped
+end
+
+# This is the interfacing class represents the API that we intend to provide the
+# plugins to use.
+#
+# For plugins to be independent of the
+# [`Bundler`](https://docs.ruby-lang.org/en/2.7.0/Bundler.html) internals they
+# shall limit their interactions to methods of this class only. This will save
+# them from breaking when some internal change.
+#
+# Currently we are delegating the methods defined in
+# [`Bundler`](https://docs.ruby-lang.org/en/2.7.0/Bundler.html) class to itself.
+# So, this class acts as a buffer.
+#
+# If there is some change in the
+# [`Bundler`](https://docs.ruby-lang.org/en/2.7.0/Bundler.html) class that is
+# incompatible to its previous behavior or if otherwise desired, we can
+# reimplement(or implement) the method to preserve compatibility.
+#
+# To use this, either the class can inherit this class or use it directly. For
+# example of both types of use, refer the file `spec/plugins/command.rb`
+#
+# To use it without inheriting, you will have to create an object of this to use
+# the functions (except for declaration functions like command, source, and
+# hooks).
+# Manages which plugins are installed and their sources. This also is supposed
+# to map which plugin does what (currently the features are not implemented so
+# this class is now a stub class).
+# Handles the installation of plugin in appropriate directories.
+#
+# This class is supposed to be wrapper over the existing gem installation infra
+# but currently it itself handles everything as the Source's subclasses (e.g.
+# Source::RubyGems) are heavily dependent on the Gemfile.
+# SourceList object to be used while parsing the Gemfile, setting the
+# approptiate options to be used with Source classes for plugin installation
+module Bundler::Plugin
+  def self.add_command: (untyped command, untyped cls) -> untyped
+
+  def self.add_hook: (untyped event) { () -> untyped } -> untyped
+
+  def self.add_source: (untyped source, untyped cls) -> untyped
+
+  def self.cache: () -> untyped
+
+  def self.command?: (untyped command) -> untyped
+
+  def self.exec_command: (untyped command, untyped args) -> untyped
+
+  def self.gemfile_install: (?untyped gemfile) { () -> untyped } -> untyped
+
+  def self.global_root: () -> untyped
+
+  def self.hook: (untyped event, *untyped args) { () -> untyped } -> untyped
+
+  def self.index: () -> untyped
+
+  def self.install: (untyped names, untyped options) -> untyped
+
+  def self.installed?: (untyped plugin) -> untyped
+
+  def self.local_root: () -> untyped
+
+  def self.reset!: () -> untyped
+
+  def self.root: () -> untyped
+
+  def self.source: (untyped name) -> untyped
+
+  def self.source?: (untyped name) -> untyped
+
+  def self.source_from_lock: (untyped locked_opts) -> untyped
+end
+
+Bundler::Plugin::PLUGIN_FILE_NAME: untyped
+
+class Bundler::Plugin::API
+  # The cache dir to be used by the plugins for storage
+  #
+  # @return [Pathname] path of the cache dir
+  def cache_dir: () -> untyped
+
+  def method_missing: (untyped name, *untyped args) { () -> untyped } -> untyped
+
+  def tmp: (*untyped names) -> untyped
+
+  def self.command: (untyped command, ?untyped cls) -> untyped
+
+  def self.hook: (untyped event) { () -> untyped } -> untyped
+
+  def self.source: (untyped source, ?untyped cls) -> untyped
+end
+
+# Dsl to parse the Gemfile looking for plugins to install
+class Bundler::Plugin::DSL < Bundler::Dsl
+  def _gem: (untyped name, *untyped args) -> untyped
+
+  # This lists the plugins that was added automatically and not specified by the
+  # user.
+  #
+  # When we encounter :type attribute with a source block, we add a plugin by
+  # name bundler-source-<type> to list of plugins to be installed.
+  #
+  # These plugins are optional and are not installed when there is conflict with
+  # any other plugin.
+  def inferred_plugins: () -> untyped
+
+  def plugin: (untyped name, *untyped args) -> untyped
+end
+
+module Bundler::Plugin::Events
+end
+
+class Bundler::Plugin::Index
+end
+
+class Bundler::Plugin::MalformattedPlugin < Bundler::PluginError
+end
+
+class Bundler::Plugin::UndefinedCommandError < Bundler::PluginError
+end
+
+class Bundler::Plugin::UnknownSourceError < Bundler::PluginError
+end
+
+class Bundler::Plugin::DSL::PluginGemfileError < Bundler::PluginError
+end
+
+class Bundler::PluginError < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+class Bundler::ProductionError < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+# Represents a lazily loaded gem specification, where the full specification is
+# on the source server in rubygems' "quick" index. The proxy object is to be
+# seeded with what we're given from the source's abbreviated index - the full
+# specification will only be fetched when necessary.
+class Bundler::RemoteSpecification
+  include ::Comparable
+
+  include ::Bundler::MatchPlatform
+
+  include ::Bundler::GemHelpers
+
+  def <=>: (untyped other) -> untyped
+
+  def __swap__: (untyped spec) -> untyped
+
+  def dependencies: () -> untyped
+
+  def dependencies=: (untyped dependencies) -> untyped
+
+  # Needed before installs, since the arch matters then and quick specs don't
+  # bother to include the arch in the platform string
+  def fetch_platform: () -> untyped
+
+  def full_name: () -> untyped
+
+  def git_version: () -> untyped
+
+  def initialize: (untyped name, untyped version, untyped platform, untyped spec_fetcher) -> void
+
+  def name: () -> String
+
+  def platform: () -> untyped
+
+  def remote: () -> untyped
+
+  def remote=: (untyped remote) -> untyped
+
+  def respond_to?: (untyped method, ?untyped include_all) -> untyped
+
+  # Create a delegate used for sorting. This strategy is copied from RubyGems
+  # 2.23 and ensures that Bundler's specifications can be compared and sorted
+  # with RubyGems' own specifications.
+  #
+  # @see #<=> @see
+  # [`Gem::Specification#sort_obj`](https://docs.ruby-lang.org/en/2.7.0/Gem/Specification.html#method-i-sort_obj)
+  #
+  # @return [Array] an object you can use to compare and sort this
+  #
+  # ```ruby
+  # specification against other specifications
+  # ```
+  def sort_obj: () -> untyped
+
+  def source: () -> untyped
+
+  def source=: (untyped source) -> untyped
+
+  def to_s: () -> untyped
+
+  def version: () -> String
+end
+
+class Bundler::Resolver
+  include ::Bundler::Molinillo::SpecificationProvider
+
+  include ::Bundler::Molinillo::UI
+
+  def after_resolution: () -> untyped
+
+  def before_resolution: () -> untyped
+
+  def debug: (?untyped depth) -> untyped
+
+  def debug?: () -> untyped
+
+  def dependencies_for: (untyped specification) -> untyped
+
+  def index_for: (untyped dependency) -> untyped
+
+  def indicate_progress: () -> untyped
+
+  def initialize: (untyped index, untyped source_requirements, untyped base, untyped gem_version_promoter, untyped additional_base_requirements, untyped platforms) -> void
+
+  def name_for: (untyped dependency) -> untyped
+
+  def name_for_explicit_dependency_source: () -> untyped
+
+  def name_for_locking_dependency_source: () -> untyped
+
+  def relevant_sources_for_vertex: (untyped vertex) -> untyped
+
+  def requirement_satisfied_by?: (untyped requirement, untyped activated, untyped spec) -> untyped
+
+  def search_for: (untyped dependency) -> untyped
+
+  def sort_dependencies: (untyped dependencies, untyped activated, untyped conflicts) -> untyped
+
+  def start: (untyped requirements) -> untyped
+
+  def self.platform_sort_key: (untyped platform) -> untyped
+
+  def self.resolve: (untyped requirements, untyped index, ?untyped source_requirements, ?untyped base, ?untyped gem_version_promoter, ?untyped additional_base_requirements, ?untyped platforms) -> untyped
+
+  def self.sort_platforms: (untyped platforms) -> untyped
+end
+
+class Bundler::Resolver::SpecGroup
+  include ::Bundler::GemHelpers
+
+  def ==: (untyped other) -> untyped
+
+  def activate_platform!: (untyped platform) -> untyped
+
+  def dependencies_for_activated_platforms: () -> untyped
+
+  def eql?: (untyped other) -> untyped
+
+  def for?: (untyped platform) -> untyped
+
+  def hash: () -> untyped
+
+  def ignores_bundler_dependencies: () -> untyped
+
+  def ignores_bundler_dependencies=: (untyped ignores_bundler_dependencies) -> untyped
+
+  def initialize: (untyped all_specs) -> void
+
+  def name: () -> untyped
+
+  def name=: (untyped name) -> untyped
+
+  def source: () -> untyped
+
+  def source=: (untyped source) -> untyped
+
+  def to_s: () -> untyped
+
+  def to_specs: () -> untyped
+
+  def version: () -> untyped
+
+  def version=: (untyped version) -> untyped
+end
+
+module Bundler::RubyDsl
+  @ruby_version: untyped
+
+  def ruby: (*::String ruby_version) -> void
+
+  # Support the various file formats found in .ruby-version files.
+  #
+  #     3.2.2
+  #     ruby-3.2.2
+  #
+  # Also supports .tool-versions files for asdf. Lines not starting with "ruby" are ignored.
+  #
+  #     ruby 2.5.1 # comment is ignored
+  #     ruby   2.5.1# close comment and extra spaces doesn't confuse
+  #
+  # Intentionally does not support `3.2.1@gemset` since rvm recommends using .ruby-gemset instead
+  #
+  # Loads the file relative to the dirname of the Gemfile itself.
+  def normalize_ruby_file: (::String filename) -> ::String
+end
+
+class Bundler::RubyVersion
+  def ==: (untyped other) -> untyped
+
+  def diff: (untyped other) -> untyped
+
+  def engine: () -> untyped
+
+  def engine_gem_version: () -> untyped
+
+  def engine_versions: () -> untyped
+
+  def exact?: () -> untyped
+
+  def gem_version: () -> untyped
+
+  def host: () -> untyped
+
+  def initialize: (untyped versions, untyped patchlevel, untyped engine, untyped engine_version) -> void
+
+  def patchlevel: () -> untyped
+
+  def single_version_string: () -> untyped
+
+  def to_gem_version_with_patchlevel: () -> untyped
+
+  def to_s: (?untyped versions) -> untyped
+
+  def versions: () -> untyped
+
+  def versions_string: (untyped versions) -> untyped
+
+  def self.from_string: (untyped string) -> untyped
+
+  def self.system: () -> untyped
+end
+
+Bundler::RubyVersion::PATTERN: untyped
+
+class Bundler::RubyVersionMismatch < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+class Bundler::RubygemsIntegration
+  # This backports base\_dir which replaces installation path RubyGems 1.8+
+  def backport_base_dir: () -> untyped
+
+  def backport_cache_file: () -> untyped
+
+  # This backports the correct segment generation code from RubyGems 1.4+ by
+  # monkeypatching it into the method in RubyGems 1.3.6 and 1.3.7.
+  def backport_segment_generation: () -> untyped
+
+  def backport_spec_file: () -> untyped
+
+  # This backport fixes the marshaling of @segments.
+  def backport_yaml_initialize: () -> untyped
+
+  def bin_path: (untyped gem, untyped bin, untyped ver) -> untyped
+
+  def binstubs_call_gem?: () -> untyped
+
+  def build: (untyped spec, ?untyped skip_validation) -> untyped
+
+  def build_args: () -> untyped
+
+  def build_args=: (untyped args) -> untyped
+
+  def build_gem: (untyped gem_dir, untyped spec) -> untyped
+
+  def clear_paths: () -> untyped
+
+  def config_map: () -> untyped
+
+  def configuration: () -> untyped
+
+  def download_gem: (untyped spec, untyped uri, untyped path) -> untyped
+
+  def ext_lock: () -> untyped
+
+  def fetch_all_remote_specs: (untyped remote) -> untyped
+
+  def fetch_prerelease_specs: () -> untyped
+
+  def fetch_specs: (untyped all, untyped pre) { () -> untyped } -> untyped
+
+  def gem_bindir: () -> untyped
+
+  def gem_cache: () -> untyped
+
+  def gem_dir: () -> untyped
+
+  def gem_from_path: (untyped path, ?untyped policy) -> untyped
+
+  def gem_path: () -> untyped
+
+  def inflate: (untyped obj) -> untyped
+
+  def initialize: () -> void
+
+  def install_with_build_args: (untyped args) -> untyped
+
+  def load_path_insert_index: () -> untyped
+
+  def load_plugin_files: (untyped files) -> untyped
+
+  def load_plugins: () -> untyped
+
+  def loaded_gem_paths: () -> untyped
+
+  def loaded_specs: (untyped name) -> untyped
+
+  def mark_loaded: (untyped spec) -> untyped
+
+  def marshal_spec_dir: () -> untyped
+
+  def method_visibility: (untyped klass, untyped method) -> untyped
+
+  def path: (untyped obj) -> untyped
+
+  def path_separator: () -> untyped
+
+  def platforms: () -> untyped
+
+  def post_reset_hooks: () -> untyped
+
+  def preserve_paths: () -> untyped
+
+  def provides?: (untyped req_str) -> untyped
+
+  def read_binary: (untyped path) -> untyped
+
+  def redefine_method: (untyped klass, untyped method, ?untyped unbound_method) { () -> untyped } -> untyped
+
+  def replace_bin_path: (untyped specs, untyped specs_by_name) -> untyped
+
+  def replace_entrypoints: (untyped specs) -> untyped
+
+  def replace_gem: (untyped specs, untyped specs_by_name) -> untyped
+
+  # Because [`Bundler`](https://docs.ruby-lang.org/en/2.6.0/Bundler.html) has a
+  # static view of what specs are available, we don't refresh, so stub it out.
+  def replace_refresh: () -> untyped
+
+  def repository_subdirectories: () -> untyped
+
+  def reset: () -> untyped
+
+  def reverse_rubygems_kernel_mixin: () -> untyped
+
+  def ruby_engine: () -> untyped
+
+  def security_policies: () -> untyped
+
+  def security_policy_keys: () -> untyped
+
+  def set_installed_by_version: (untyped spec, ?untyped installed_by_version) -> untyped
+
+  def sources: () -> untyped
+
+  def sources=: (untyped val) -> untyped
+
+  def spec_cache_dirs: () -> untyped
+
+  def spec_default_gem?: (untyped spec) -> untyped
+
+  def spec_extension_dir: (untyped spec) -> untyped
+
+  def spec_from_gem: (untyped path, ?untyped policy) -> untyped
+
+  def spec_matches_for_glob: (untyped spec, untyped glob) -> untyped
+
+  def spec_missing_extensions?: (untyped spec, ?untyped default) -> untyped
+
+  def stub_set_spec: (untyped stub, untyped spec) -> untyped
+
+  def stub_source_index: (untyped specs) -> untyped
+
+  def stubs_provide_full_functionality?: () -> untyped
+
+  def suffix_pattern: () -> untyped
+
+  def ui=: (untyped obj) -> untyped
+
+  def undo_replacements: () -> untyped
+
+  def user_home: () -> untyped
+
+  def validate: (untyped spec) -> untyped
+
+  def version: () -> untyped
+
+  def with_build_args: (untyped args) -> untyped
+
+  def self.provides?: (untyped req_str) -> untyped
+
+  def self.version: () -> untyped
+end
+
+Bundler::RubygemsIntegration::EXT_LOCK: untyped
+
+# RubyGems 1.8.0 to 1.8.4
+class Bundler::RubygemsIntegration::AlmostModern < Bundler::RubygemsIntegration::Modern
+  # RubyGems [>= 1.8.0, < 1.8.5] has a bug that changes
+  # [`Gem.dir`](https://docs.ruby-lang.org/en/2.6.0/Gem.html#method-c-dir)
+  # whenever you call
+  # [`Gem::Installer#install`](https://docs.ruby-lang.org/en/2.6.0/Installer.html#method-i-install)
+  # with an :install\_dir set. We have to change it back for our sudo mode to
+  # work.
+  def preserve_paths: () -> untyped
+end
+
+# RubyGems versions 1.3.6 and 1.3.7
+class Bundler::RubygemsIntegration::Ancient < Bundler::RubygemsIntegration::Legacy
+  def initialize: () -> void
+end
+
+# RubyGems 2.0
+class Bundler::RubygemsIntegration::Future < Bundler::RubygemsIntegration
+  def all_specs: () -> untyped
+
+  def build: (untyped spec, ?untyped skip_validation) -> untyped
+
+  def download_gem: (untyped spec, untyped uri, untyped path) -> untyped
+
+  def fetch_all_remote_specs: (untyped remote) -> untyped
+
+  def fetch_specs: (untyped source, untyped remote, untyped name) -> untyped
+
+  def find_name: (untyped name) -> untyped
+
+  def gem_from_path: (untyped path, ?untyped policy) -> untyped
+
+  def gem_remote_fetcher: () -> untyped
+
+  def install_with_build_args: (untyped args) -> untyped
+
+  def path_separator: () -> untyped
+
+  def repository_subdirectories: () -> untyped
+
+  def stub_rubygems: (untyped specs) -> untyped
+end
+
+# RubyGems 1.4 through 1.6
+class Bundler::RubygemsIntegration::Legacy < Bundler::RubygemsIntegration
+  def all_specs: () -> untyped
+
+  def find_name: (untyped name) -> untyped
+
+  def initialize: () -> void
+
+  def post_reset_hooks: () -> untyped
+
+  def reset: () -> untyped
+
+  def stub_rubygems: (untyped specs) -> untyped
+
+  def validate: (untyped spec) -> untyped
+end
+
+# RubyGems 1.8.5-1.8.19
+class Bundler::RubygemsIntegration::Modern < Bundler::RubygemsIntegration
+  def all_specs: () -> untyped
+
+  def find_name: (untyped name) -> untyped
+
+  def stub_rubygems: (untyped specs) -> untyped
+end
+
+# RubyGems 2.1.0
+class Bundler::RubygemsIntegration::MoreFuture < Bundler::RubygemsIntegration::Future
+  def all_specs: () -> untyped
+
+  # RubyGems-generated binstubs call
+  # [`Kernel#gem`](https://docs.ruby-lang.org/en/2.6.0/Kernel.html#method-i-gem)
+  def binstubs_call_gem?: () -> untyped
+
+  def find_name: (untyped name) -> untyped
+
+  def initialize: () -> void
+
+  # only 2.5.2+ has all of the stub methods we want to use, and since this is a
+  # performance optimization *only*, we'll restrict ourselves to the most recent
+  # RG versions instead of all versions that have stubs
+  def stubs_provide_full_functionality?: () -> untyped
+
+  def use_gemdeps: (untyped gemfile) -> untyped
+end
+
+# RubyGems 1.8.20+
+class Bundler::RubygemsIntegration::MoreModern < Bundler::RubygemsIntegration::Modern
+  def build: (untyped spec, ?untyped skip_validation) -> untyped
+end
+
+# RubyGems 1.7
+class Bundler::RubygemsIntegration::Transitional < Bundler::RubygemsIntegration::Legacy
+  def stub_rubygems: (untyped specs) -> untyped
+
+  def validate: (untyped spec) -> untyped
+end
+
+class Bundler::Runtime
+  include ::Bundler::SharedHelpers
+
+  def cache: (?untyped custom_path) -> untyped
+
+  def clean: (?untyped dry_run) -> untyped
+
+  def current_dependencies: () -> untyped
+
+  def dependencies: () -> untyped
+
+  def gems: () -> untyped
+
+  def initialize: (untyped root, untyped definition) -> void
+
+  def lock: (?untyped opts) -> untyped
+
+  def prune_cache: (untyped cache_path) -> untyped
+
+  def requested_specs: () -> untyped
+
+  def require: (*untyped groups) -> untyped
+
+  def requires: () -> untyped
+
+  def setup: (*untyped groups) -> untyped
+
+  def specs: () -> untyped
+end
+
+Bundler::Runtime::REQUIRE_ERRORS: untyped
+
+class Bundler::SecurityError < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+class Bundler::Settings
+  def []: (untyped name) -> untyped
+
+  def all: () -> untyped
+
+  def allow_sudo?: () -> untyped
+
+  def app_cache_path: () -> untyped
+
+  def credentials_for: (untyped uri) -> untyped
+
+  def gem_mirrors: () -> untyped
+
+  def ignore_config?: () -> untyped
+
+  def initialize: (?untyped root) -> void
+
+  def key_for: (untyped key) -> untyped
+
+  def local_overrides: () -> untyped
+
+  def locations: (untyped key) -> untyped
+
+  def mirror_for: (untyped uri) -> untyped
+
+  # for legacy reasons, in
+  # [`Bundler`](https://docs.ruby-lang.org/en/2.7.0/Bundler.html) 2, we do not
+  # respect :disable\_shared\_gems
+  def path: () -> untyped
+
+  def pretty_values_for: (untyped exposed_key) -> untyped
+
+  def set_command_option: (untyped key, untyped value) -> untyped
+
+  def set_command_option_if_given: (untyped key, untyped value) -> untyped
+
+  def set_global: (untyped key, untyped value) -> untyped
+
+  def set_local: (untyped key, untyped value) -> untyped
+
+  def temporary: (untyped update) -> untyped
+
+  def validate!: () -> untyped
+
+  def self.normalize_uri: (untyped uri) -> untyped
+end
+
+Bundler::Settings::ARRAY_KEYS: untyped
+
+Bundler::Settings::BOOL_KEYS: untyped
+
+Bundler::Settings::CONFIG_REGEX: untyped
+
+Bundler::Settings::DEFAULT_CONFIG: untyped
+
+Bundler::Settings::NORMALIZE_URI_OPTIONS_PATTERN: untyped
+
+Bundler::Settings::NUMBER_KEYS: untyped
+
+Bundler::Settings::PER_URI_OPTIONS: untyped
+
+class Bundler::Settings::Path < Struct
+  def append_ruby_scope: () -> untyped
+
+  def append_ruby_scope=: (untyped _) -> untyped
+
+  def base_path: () -> untyped
+
+  def base_path_relative_to_pwd: () -> untyped
+
+  def default_install_uses_path: () -> untyped
+
+  def default_install_uses_path=: (untyped _) -> untyped
+
+  def explicit_path: () -> untyped
+
+  def explicit_path=: (untyped _) -> untyped
+
+  def path: () -> untyped
+
+  def system_path: () -> untyped
+
+  def system_path=: (untyped _) -> untyped
+
+  def use_system_gems?: () -> untyped
+
+  def validate!: () -> untyped
+
+  def self.[]: (*untyped _) -> untyped
+
+  def self.members: () -> untyped
+
+  def self.new: (*untyped _) -> untyped
+end
+
+Bundler::Settings::Path::Elem: untyped
+
+module Bundler::SharedHelpers
+  extend ::Bundler::SharedHelpers
+
+  def chdir: (untyped dir) { () -> untyped } -> untyped
+
+  def const_get_safely: (untyped constant_name, untyped namespace) -> untyped
+
+  def default_bundle_dir: () -> untyped
+
+  def default_gemfile: () -> untyped
+
+  def default_lockfile: () -> untyped
+
+  def digest: (untyped name) -> untyped
+
+  def ensure_same_dependencies: (untyped spec, untyped old_deps, untyped new_deps) -> untyped
+
+  def filesystem_access: (untyped path, ?untyped action) { () -> untyped } -> untyped
+
+  def in_bundle?: () -> untyped
+
+  def major_deprecation: (untyped major_version, untyped message) -> untyped
+
+  def md5_available?: () -> untyped
+
+  def pretty_dependency: (untyped dep, ?untyped print_source) -> untyped
+
+  def print_major_deprecations!: () -> untyped
+
+  def pwd: () -> untyped
+
+  def root: () -> untyped
+
+  def set_bundle_environment: () -> untyped
+
+  def set_env: (untyped key, untyped value) -> untyped
+
+  def trap: (untyped signal, ?untyped override) { () -> untyped } -> untyped
+
+  def with_clean_git_env: () { () -> untyped } -> untyped
+
+  def write_to_gemfile: (untyped gemfile_path, untyped contents) -> untyped
+end
+
+class Bundler::Source
+  def can_lock?: (untyped spec) -> untyped
+
+  def dependency_names: () -> untyped
+
+  def dependency_names=: (untyped dependency_names) -> untyped
+
+  def dependency_names_to_double_check: () -> untyped
+
+  def double_check_for: (*untyped _) -> untyped
+
+  def extension_cache_path: (untyped spec) -> untyped
+
+  def include?: (untyped other) -> untyped
+
+  def inspect: () -> untyped
+
+  def path?: () -> untyped
+
+  def unmet_deps: () -> untyped
+
+  def version_message: (untyped spec) -> untyped
+end
+
+class Bundler::Source::Gemspec < Bundler::Source::Path
+  def as_path_source: () -> untyped
+
+  def gemspec: () -> untyped
+
+  def initialize: (untyped options) -> void
+end
+
+class Bundler::Source::Git < Bundler::Source::Path
+  def ==: (untyped other) -> untyped
+
+  def allow_git_ops?: () -> untyped
+
+  def app_cache_dirname: () -> untyped
+
+  def branch: () -> untyped
+
+  def cache: (untyped spec, ?untyped custom_path) -> untyped
+
+  # This is the path which is going to contain a cache of the git repository.
+  # When using the same git repository across different projects, this cache
+  # will be shared. When using local git repos, this is set to the local repo.
+  def cache_path: () -> untyped
+
+  def eql?: (untyped other) -> untyped
+
+  def extension_dir_name: () -> untyped
+
+  def hash: () -> untyped
+
+  def initialize: (untyped options) -> void
+
+  def install: (untyped spec, ?untyped options) -> untyped
+
+  # This is the path which is going to contain a specific checkout of the git
+  # repository. When using local git repos, this is set to the local repo.
+  #
+  # Also aliased as:
+  # [`path`](https://docs.ruby-lang.org/en/2.7.0/Bundler/Source/Git.html#method-i-path)
+  def install_path: () -> untyped
+
+  def load_spec_files: () -> untyped
+
+  def local_override!: (untyped path) -> untyped
+
+  def name: () -> untyped
+
+  def options: () -> untyped
+
+  # Alias for:
+  # [`install_path`](https://docs.ruby-lang.org/en/2.7.0/Bundler/Source/Git.html#method-i-install_path)
+  def path: () -> untyped
+
+  def ref: () -> untyped
+
+  def revision: () -> untyped
+
+  def specs: (*untyped _) -> untyped
+
+  def submodules: () -> untyped
+
+  def to_lock: () -> untyped
+
+  def to_s: () -> untyped
+
+  def unlock!: () -> untyped
+
+  def uri: () -> untyped
+
+  def self.from_lock: (untyped options) -> untyped
+end
+
+class Bundler::Source::Git::GitCommandError < Bundler::GitError
+  def initialize: (untyped command, ?untyped path, ?untyped extra_info) -> void
+end
+
+class Bundler::Source::Git::GitNotAllowedError < Bundler::GitError
+  def initialize: (untyped command) -> void
+end
+
+class Bundler::Source::Git::GitNotInstalledError < Bundler::GitError
+  def initialize: () -> void
+end
+
+# The
+# [`GitProxy`](https://docs.ruby-lang.org/en/2.7.0/Bundler/Source/Git/GitProxy.html)
+# is responsible to interact with git repositories. All actions required by the
+# [`Git`](https://docs.ruby-lang.org/en/2.7.0/Bundler/Source/Git.html) source is
+# encapsulated in this object.
+class Bundler::Source::Git::GitProxy
+  def branch: () -> untyped
+
+  def checkout: () -> untyped
+
+  def contains?: (untyped commit) -> untyped
+
+  def copy_to: (untyped destination, ?untyped submodules) -> untyped
+
+  def full_version: () -> untyped
+
+  def initialize: (untyped path, untyped uri, untyped ref, ?untyped revision, ?untyped git) -> void
+
+  def path: () -> untyped
+
+  def path=: (untyped path) -> untyped
+
+  def ref: () -> untyped
+
+  def ref=: (untyped ref) -> untyped
+
+  def revision: () -> untyped
+
+  def revision=: (untyped revision) -> untyped
+
+  def uri: () -> untyped
+
+  def uri=: (untyped uri) -> untyped
+
+  def version: () -> untyped
+end
+
+class Bundler::Source::Git::MissingGitRevisionError < Bundler::GitError
+  def initialize: (untyped ref, untyped repo) -> void
+end
+
+class Bundler::Source::Metadata < Bundler::Source
+  def ==: (untyped other) -> untyped
+
+  def cached!: () -> untyped
+
+  def eql?: (untyped other) -> untyped
+
+  def hash: () -> untyped
+
+  def install: (untyped spec, ?untyped _opts) -> untyped
+
+  def options: () -> untyped
+
+  def remote!: () -> untyped
+
+  def specs: () -> untyped
+
+  def to_s: () -> untyped
+
+  def version_message: (untyped spec) -> untyped
+end
+
+class Bundler::Source::Path < Bundler::Source
+  def ==: (untyped other) -> untyped
+
+  def app_cache_dirname: () -> untyped
+
+  def cache: (untyped spec, ?untyped custom_path) -> untyped
+
+  def cached!: () -> untyped
+
+  def eql?: (untyped other) -> untyped
+
+  def expanded_original_path: () -> untyped
+
+  def hash: () -> untyped
+
+  def initialize: (untyped options) -> void
+
+  def install: (untyped spec, ?untyped options) -> untyped
+
+  def local_specs: (*untyped _) -> untyped
+
+  def name: () -> untyped
+
+  def name=: (untyped name) -> untyped
+
+  def options: () -> untyped
+
+  def original_path: () -> untyped
+
+  def path: () -> untyped
+
+  def remote!: () -> untyped
+
+  def root: () -> untyped
+
+  def root_path: () -> untyped
+
+  def specs: () -> untyped
+
+  def to_lock: () -> untyped
+
+  def to_s: () -> untyped
+
+  def version: () -> untyped
+
+  def version=: (untyped version) -> untyped
+
+  def self.from_lock: (untyped options) -> untyped
+end
+
+Bundler::Source::Path::DEFAULT_GLOB: untyped
+
+class Bundler::Source::Rubygems < Bundler::Source
+  def ==: (untyped other) -> untyped
+
+  def add_remote: (untyped source) -> untyped
+
+  def api_fetchers: () -> untyped
+
+  def builtin_gem?: (untyped spec) -> untyped
+
+  def cache: (untyped spec, ?untyped custom_path) -> untyped
+
+  def cache_path: () -> untyped
+
+  def cached!: () -> untyped
+
+  def cached_built_in_gem: (untyped spec) -> untyped
+
+  def cached_gem: (untyped spec) -> untyped
+
+  def cached_path: (untyped spec) -> untyped
+
+  def cached_specs: () -> untyped
+
+  def caches: () -> untyped
+
+  def can_lock?: (untyped spec) -> untyped
+
+  def credless_remotes: () -> untyped
+
+  def dependency_names_to_double_check: () -> untyped
+
+  def double_check_for: (untyped unmet_dependency_names) -> untyped
+
+  def eql?: (untyped other) -> untyped
+
+  def equivalent_remotes?: (untyped other_remotes) -> untyped
+
+  def fetch_gem: (untyped spec) -> untyped
+
+  def fetch_names: (untyped fetchers, untyped dependency_names, untyped index, untyped override_dupes) -> untyped
+
+  def fetchers: () -> untyped
+
+  def hash: () -> untyped
+
+  def include?: (untyped o) -> untyped
+
+  def initialize: (?untyped options) -> void
+
+  def install: (untyped spec, ?untyped opts) -> untyped
+
+  def installed?: (untyped spec) -> untyped
+
+  def installed_specs: () -> untyped
+
+  def loaded_from: (untyped spec) -> untyped
+
+  # Alias for:
+  # [`to_s`](https://docs.ruby-lang.org/en/2.7.0/Bundler/Source/Rubygems.html#method-i-to_s)
+  def name: () -> untyped
+
+  def normalize_uri: (untyped uri) -> untyped
+
+  def options: () -> untyped
+
+  def remote!: () -> untyped
+
+  def remote_specs: () -> untyped
+
+  def remotes: () -> untyped
+
+  def remotes_for_spec: (untyped spec) -> untyped
+
+  def remove_auth: (untyped remote) -> untyped
+
+  def replace_remotes: (untyped other_remotes, ?untyped allow_equivalent) -> untyped
+
+  def requires_sudo?: () -> untyped
+
+  def rubygems_dir: () -> untyped
+
+  def specs: () -> untyped
+
+  def suppress_configured_credentials: (untyped remote) -> untyped
+
+  def to_lock: () -> untyped
+
+  # Also aliased as:
+  # [`name`](https://docs.ruby-lang.org/en/2.7.0/Bundler/Source/Rubygems.html#method-i-name)
+  def to_s: () -> untyped
+
+  def unmet_deps: () -> untyped
+
+  def self.from_lock: (untyped options) -> untyped
+end
+
+Bundler::Source::Rubygems::API_REQUEST_LIMIT: untyped
+
+Bundler::Source::Rubygems::API_REQUEST_SIZE: untyped
+
+class Bundler::SourceList
+  def add_git_source: (?untyped options) -> untyped
+
+  def add_path_source: (?untyped options) -> untyped
+
+  def add_plugin_source: (untyped source, ?untyped options) -> untyped
+
+  def add_rubygems_remote: (untyped uri) -> untyped
+
+  def add_rubygems_source: (?untyped options) -> untyped
+
+  def all_sources: () -> untyped
+
+  def cached!: () -> untyped
+
+  def default_source: () -> untyped
+
+  def get: (untyped source) -> untyped
+
+  def git_sources: () -> untyped
+
+  def global_rubygems_source: () -> untyped
+
+  def global_rubygems_source=: (untyped uri) -> untyped
+
+  def initialize: () -> void
+
+  def lock_sources: () -> untyped
+
+  def metadata_source: () -> untyped
+
+  def path_sources: () -> untyped
+
+  def plugin_sources: () -> untyped
+
+  def remote!: () -> untyped
+
+  def replace_sources!: (untyped replacement_sources) -> untyped
+
+  def rubygems_primary_remotes: () -> untyped
+
+  def rubygems_remotes: () -> untyped
+
+  def rubygems_sources: () -> untyped
+end
+
+class Bundler::SpecSet[out Elem]
+  include ::TSort
+
+  include ::Enumerable
+
+  def <<: (*untyped args) { () -> untyped } -> untyped
+
+  def []: (untyped key) -> untyped
+
+  def []=: (untyped key, untyped value) -> untyped
+
+  def add: (*untyped args) { () -> untyped } -> untyped
+
+  def each: (*untyped args) { () -> untyped } -> untyped
+
+  def empty?: (*untyped args) { () -> untyped } -> untyped
+
+  def find_by_name_and_platform: (untyped name, untyped platform) -> untyped
+
+  def for: (untyped dependencies, ?untyped skip, ?untyped check, ?untyped match_current_platform, ?untyped raise_on_missing) -> untyped
+
+  def initialize: (untyped specs) -> void
+
+  def length: (*untyped args) { () -> untyped } -> untyped
+
+  def materialize: (untyped deps, ?untyped missing_specs) -> untyped
+
+  # Materialize for all the specs in the spec set, regardless of what platform
+  # they're for This is in contrast to how for does platform filtering (and
+  # specifically different from how `materialize` calls `for` only for the
+  # current platform) @return [Array<Gem::Specification>]
+  def materialized_for_all_platforms: () -> untyped
+
+  def merge: (untyped set) -> untyped
+
+  def remove: (*untyped args) { () -> untyped } -> untyped
+
+  def size: (*untyped args) { () -> untyped } -> untyped
+
+  def sort!: () -> untyped
+
+  def to_a: () -> untyped
+
+  def to_hash: () -> untyped
+
+  def valid_for?: (untyped deps) -> untyped
+
+  def what_required: (untyped spec) -> untyped
+end
+
+class Bundler::StubSpecification < Bundler::RemoteSpecification
+  def activated: () -> untyped
+
+  def activated=: (untyped activated) -> untyped
+
+  def default_gem: () -> untyped
+
+  def default_gem?: () -> bool
+
+  def full_gem_path: () -> untyped
+
+  def full_require_paths: () -> untyped
+
+  def ignored: () -> untyped
+
+  def ignored=: (untyped ignored) -> untyped
+
+  # This is what we do in bundler/rubygems\_ext
+  # [`full_require_paths`](https://docs.ruby-lang.org/en/2.6.0/Bundler/StubSpecification.html#method-i-full_require_paths)
+  # is always implemented in >= 2.2.0
+  def load_paths: () -> untyped
+
+  def loaded_from: () -> untyped
+
+  def matches_for_glob: (untyped glob) -> untyped
+
+  # This is defined directly to avoid having to load every installed spec
+  def missing_extensions?: () -> untyped
+
+  def raw_require_paths: () -> untyped
+
+  def source=: (untyped source) -> untyped
+
+  def stub: () -> untyped
+
+  def stub=: (untyped stub) -> untyped
+
+  def to_yaml: () -> untyped
+
+  def self.from_stub: (untyped stub) -> untyped
+end
+
+class Bundler::SudoNotPermittedError < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+class Bundler::TemporaryResourceError < Bundler::PermissionError
+  def message: () -> untyped
+
+  def status_code: () -> untyped
+end
+
+class Bundler::ThreadCreationError < Bundler::BundlerError
+  def status_code: () -> untyped
+end
+
+module Bundler::UI
+end
+
+class Bundler::UI::RGProxy < Gem::SilentUI
+  def initialize: (untyped ui) -> void
+
+  def say: (untyped message) -> untyped
+end
+
+class Bundler::UI::Silent
+  def add_color: (untyped string, untyped color) -> untyped
+
+  def ask: (untyped message) -> untyped
+
+  def confirm: (untyped message, ?untyped newline) -> untyped
+
+  def debug: (untyped message, ?untyped newline) -> untyped
+
+  def debug?: () -> untyped
+
+  def error: (untyped message, ?untyped newline) -> untyped
+
+  def info: (untyped message, ?untyped newline) -> untyped
+
+  def initialize: () -> void
+
+  def level: (?untyped name) -> untyped
+
+  def level=: (untyped name) -> untyped
+
+  def no?: () -> untyped
+
+  def quiet?: () -> untyped
+
+  def shell=: (untyped shell) -> untyped
+
+  def silence: () -> untyped
+
+  def trace: (untyped message, ?untyped newline, ?untyped force) -> untyped
+
+  def unprinted_warnings: () -> untyped
+
+  def warn: (untyped message, ?untyped newline) -> untyped
+
+  def yes?: (untyped msg) -> untyped
+end
+
+module Bundler::URICredentialsFilter
+  def self.credential_filtered_string: (untyped str_to_filter, untyped uri) -> untyped
+
+  def self.credential_filtered_uri: (untyped uri_to_anonymize) -> untyped
+end
+
+# Internal error, should be rescued
+class Bundler::VersionConflict < Bundler::BundlerError
+  def conflicts: () -> untyped
+
+  def initialize: (untyped conflicts, ?untyped msg) -> void
+
+  def status_code: () -> untyped
+end
+
+class Bundler::VirtualProtocolError < Bundler::BundlerError
+  def message: () -> untyped
+
+  def status_code: () -> untyped
+end
+
+# A stub yaml serializer that can handle only hashes and strings (as of now).
+module Bundler::YAMLSerializer
+  def self.dump: (untyped hash) -> untyped
+
+  def self.load: (untyped str) -> untyped
+end
+
+Bundler::YAMLSerializer::ARRAY_REGEX: untyped
+
+Bundler::YAMLSerializer::HASH_REGEX: untyped
+
+class Bundler::YamlSyntaxError < Bundler::BundlerError
+  def initialize: (untyped orig_exception, untyped msg) -> void
+
+  def orig_exception: () -> untyped
+
+  def status_code: () -> untyped
+end
+
+class Bundler::Installer
+  def self.ambiguous_gems=: (untyped ambiguous_gems) -> untyped
+
+  def self.ambiguous_gems: () -> untyped
+
+  def post_install_messages: () -> untyped
+
+  def self.install: (untyped root, untyped definition, ?untyped options) -> untyped
+
+  def initialize: (untyped root, untyped definition) -> void
+
+  def run: (untyped options) -> void
+
+  def generate_bundler_executable_stubs: (untyped spec, ?untyped options) -> void
+
+  def generate_standalone_bundler_executable_stubs: (untyped spec, ?untyped options) -> void
+end
diff --git a/rbs/fills/open3/0/open3.rbs b/rbs/fills/open3/0/open3.rbs
new file mode 100644
index 000000000..11d909572
--- /dev/null
+++ b/rbs/fills/open3/0/open3.rbs
@@ -0,0 +1,172 @@
+# <!-- rdoc-file=lib/open3.rb -->
+# Module Open3 supports creating child processes with access to their $stdin,
+# $stdout, and $stderr streams.
+#
+# ## What's Here
+#
+# Each of these methods executes a given command in a new process or subshell,
+# or multiple commands in new processes and/or subshells:
+#
+# *   Each of these methods executes a single command in a process or subshell,
+#     accepts a string for input to $stdin, and returns string output from
+#     $stdout, $stderr, or both:
+#
+#     *   Open3.capture2: Executes the command; returns the string from $stdout.
+#     *   Open3.capture2e: Executes the command; returns the string from merged
+#         $stdout and $stderr.
+#     *   Open3.capture3: Executes the command; returns strings from $stdout and
+#         $stderr.
+#
+# *   Each of these methods executes a single command in a process or subshell,
+#     and returns pipes for $stdin, $stdout, and/or $stderr:
+#
+#     *   Open3.popen2: Executes the command; returns pipes for $stdin and
+#         $stdout.
+#     *   Open3.popen2e: Executes the command; returns pipes for $stdin and
+#         merged $stdout and $stderr.
+#     *   Open3.popen3: Executes the command; returns pipes for $stdin, $stdout,
+#         and $stderr.
+#
+# *   Each of these methods executes one or more commands in processes and/or
+#     subshells, returns pipes for the first $stdin, the last $stdout, or both:
+#
+#     *   Open3.pipeline_r: Returns a pipe for the last $stdout.
+#     *   Open3.pipeline_rw: Returns pipes for the first $stdin and the last
+#         $stdout.
+#     *   Open3.pipeline_w: Returns a pipe for the first $stdin.
+#     *   Open3.pipeline_start: Does not wait for processes to complete.
+#     *   Open3.pipeline: Waits for processes to complete.
+#
+# Each of the methods above accepts:
+#
+# *   An optional hash of environment variable names and values; see [Execution
+#     Environment](rdoc-ref:Process@Execution+Environment).
+# *   A required string argument that is a `command_line` or `exe_path`; see
+#     [Argument command_line or
+#     exe_path](rdoc-ref:Process@Argument+command_line+or+exe_path).
+# *   An optional hash of execution options; see [Execution
+#     Options](rdoc-ref:Process@Execution+Options).
+#
+module Open3
+  # <!--
+  #   rdoc-file=lib/open3.rb
+  #   - Open3.capture2e([env, ] command_line, options = {}) -> [stdout_and_stderr_s, status]
+  #   - Open3.capture2e([env, ] exe_path, *args, options = {}) -> [stdout_and_stderr_s, status]
+  # -->
+  # Basically a wrapper for Open3.popen3 that:
+  #
+  # *   Creates a child process, by calling Open3.popen3 with the given arguments
+  #     (except for certain entries in hash `options`; see below).
+  # *   Returns as string `stdout_and_stderr_s` the merged standard output and
+  #     standard error of the child process.
+  # *   Returns as `status` a `Process::Status` object that represents the exit
+  #     status of the child process.
+  #
+  # Returns the array `[stdout_and_stderr_s, status]`:
+  #
+  #     stdout_and_stderr_s, status = Open3.capture2e('echo "Foo"')
+  #     # => ["Foo\n", #<Process::Status: pid 2371692 exit 0>]
+  #
+  # Like Process.spawn, this method has potential security vulnerabilities if
+  # called with untrusted input; see [Command
+  # Injection](rdoc-ref:command_injection.rdoc@Command+Injection).
+  #
+  # Unlike Process.spawn, this method waits for the child process to exit before
+  # returning, so the caller need not do so.
+  #
+  # If the first argument is a hash, it becomes leading argument `env` in the call
+  # to Open3.popen3; see [Execution
+  # Environment](rdoc-ref:Process@Execution+Environment).
+  #
+  # If the last argument is a hash, it becomes trailing argument `options` in the
+  # call to Open3.popen3; see [Execution
+  # Options](rdoc-ref:Process@Execution+Options).
+  #
+  # The hash `options` is given; two options have local effect in method
+  # Open3.capture2e:
+  #
+  # *   If entry `options[:stdin_data]` exists, the entry is removed and its
+  #     string value is sent to the command's standard input:
+  #
+  #         Open3.capture2e('tee', stdin_data: 'Foo')
+  #         # => ["Foo", #<Process::Status: pid 2371732 exit 0>]
+  #
+  # *   If entry `options[:binmode]` exists, the entry is removed and the internal
+  #     streams are set to binary mode.
+  #
+  # The single required argument is one of the following:
+  #
+  # *   `command_line` if it is a string, and if it begins with a shell reserved
+  #     word or special built-in, or if it contains one or more metacharacters.
+  # *   `exe_path` otherwise.
+  #
+  # **Argument `command_line`**
+  #
+  # String argument `command_line` is a command line to be passed to a shell; it
+  # must begin with a shell reserved word, begin with a special built-in, or
+  # contain meta characters:
+  #
+  #     Open3.capture2e('if true; then echo "Foo"; fi') # Shell reserved word.
+  #     # => ["Foo\n", #<Process::Status: pid 2371740 exit 0>]
+  #     Open3.capture2e('echo')                         # Built-in.
+  #     # => ["\n", #<Process::Status: pid 2371774 exit 0>]
+  #     Open3.capture2e('date > date.tmp')              # Contains meta character.
+  #     # => ["", #<Process::Status: pid 2371812 exit 0>]
+  #
+  # The command line may also contain arguments and options for the command:
+  #
+  #     Open3.capture2e('echo "Foo"')
+  #     # => ["Foo\n", #<Process::Status: pid 2326183 exit 0>]
+  #
+  # **Argument `exe_path`**
+  #
+  # Argument `exe_path` is one of the following:
+  #
+  # *   The string path to an executable to be called.
+  # *   A 2-element array containing the path to an executable and the string to
+  #     be used as the name of the executing process.
+  #
+  # Example:
+  #
+  #     Open3.capture2e('/usr/bin/date')
+  #     # => ["Sat Sep 30 09:01:46 AM CDT 2023\n", #<Process::Status: pid 2371820 exit 0>]
+  #
+  # Ruby invokes the executable directly, with no shell and no shell expansion:
+  #
+  #     Open3.capture2e('doesnt_exist') # Raises Errno::ENOENT
+  #
+  # If one or more `args` is given, each is an argument or option to be passed to
+  # the executable:
+  #
+  #     Open3.capture2e('echo', 'C #')
+  #     # => ["C #\n", #<Process::Status: pid 2371856 exit 0>]
+  #     Open3.capture2e('echo', 'hello', 'world')
+  #     # => ["hello world\n", #<Process::Status: pid 2371894 exit 0>]
+  #
+  def self.capture2e: (*String, ?stdin_data: String, ?chdir: String, ?binmode: boolish) -> [String, Process::Status]
+                   |  (Hash[String, String] env, *String cmds, ?chdir: String, ?stdin_data: String, ?binmode: boolish) -> [String, Process::Status]
+
+  def self.capture2: (?Hash[String, String] env, *String cmds, ?chdir: String) -> [String, Process::Status]
+
+  def self.capture3: (?Hash[String, String] env, *String cmds, ?chdir: String) -> [String, String, Process::Status]
+
+  def self.pipeline: (?Hash[String, String] env, *String cmds, ?chdir: String) -> Array[Process::Status]
+
+  def self.pipeline_r: (?Hash[String, String] env, *String cmds, ?chdir: String) -> [IO, Process::Waiter]
+
+  def self.pipeline_rw: (?Hash[String, String] env, *String cmds, ?chdir: String) -> [IO, IO, Process::Waiter]
+
+  def self.pipeline_start: (?Hash[String, String] env, *String cmds, ?chdir: String) -> Array[Process::Waiter]
+
+  def self.pipeline_w: (?Hash[String, String] env, *String cmds, ?chdir: String) -> [IO, Process::Waiter]
+
+  def self.popen2: (?Hash[String, String] env, *String exe_path_or_cmd_with_args, ?chdir: String) -> [IO, IO, Process::Waiter]
+                 | [U] (?Hash[String, String] env, *String exe_path_or_cmd_with_args, ?chdir: String) { (IO stdin, IO stdout, Process::Waiter wait_thread) -> U } -> U
+
+  def self.popen2e: (?Hash[String, String] env, *String exe_path_or_cmd_with_args, ?chdir: String) -> [IO, IO, Process::Waiter]
+                  | [U] (?Hash[String, String] env, *String exe_path_or_cmd_with_args, ?chdir: String) { (IO stdin, IO stdout_and_stderr, Process::Waiter wait_thread) -> U } -> U
+
+  def self.popen3: (?Hash[String, String] env, *String exe_path_or_cmd_with_args, ?chdir: String) -> [IO, IO, IO, Process::Waiter]
+                 | [U] (?Hash[String, String] env, *String exe_path_or_cmd_with_args, ?chdir: String) { (IO stdin, IO stdout, IO stderr, Process::Waiter wait_thread) -> U } -> U
+
+end
diff --git a/rbs/fills/rubygems/0/basic_specification.rbs b/rbs/fills/rubygems/0/basic_specification.rbs
new file mode 100644
index 000000000..361027e67
--- /dev/null
+++ b/rbs/fills/rubygems/0/basic_specification.rbs
@@ -0,0 +1,326 @@
+# <!-- rdoc-file=lib/rubygems/basic_specification.rb -->
+# BasicSpecification is an abstract class which implements some common code used
+# by both Specification and StubSpecification.
+#
+class Gem::BasicSpecification
+  @ignored: untyped
+
+  @extension_dir: untyped
+
+  @full_gem_path: untyped
+
+  @full_require_paths: untyped
+
+  @paths_map: untyped
+
+  @gem_dir: untyped
+
+  attr_writer base_dir: untyped
+
+  attr_writer extension_dir: untyped
+
+  attr_writer ignored: untyped
+
+  # <!-- rdoc-file=lib/rubygems/basic_specification.rb -->
+  # The path this gemspec was loaded from.  This attribute is not persisted.
+  #
+  attr_accessor loaded_from: untyped
+
+  attr_writer full_gem_path: untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - new()
+  # -->
+  #
+  def initialize: () -> void
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - default_specifications_dir()
+  # -->
+  #
+  def self.default_specifications_dir: () -> untyped
+
+  extend Gem::Deprecate
+
+  def gem_build_complete_path: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - activated?()
+  # -->
+  # True when the gem has been activated
+  #
+  def activated?: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - base_dir()
+  # -->
+  # Returns the full path to the base gem directory.
+  #
+  # eg: /usr/local/lib/ruby/gems/1.8
+  #
+  def base_dir: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - contains_requirable_file?(file)
+  # -->
+  # Return true if this spec can require `file`.
+  #
+  def contains_requirable_file?: (untyped file) -> (false | untyped)
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - ignored?()
+  # -->
+  # Return true if this spec should be ignored because it's missing extensions.
+  #
+  def ignored?: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - default_gem?()
+  # -->
+  #
+  def default_gem?: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - default_gem_priority()
+  # -->
+  # Regular gems take precedence over default gems
+  #
+  def default_gem_priority: () -> (1 | -1)
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - base_dir_priority(gem_path)
+  # -->
+  # Gems higher up in `gem_path` take precedence
+  #
+  def base_dir_priority: (untyped gem_path) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - extension_dir()
+  # -->
+  # Returns full path to the directory where gem's extensions are installed.
+  #
+  def extension_dir: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - extensions_dir()
+  # -->
+  # Returns path to the extensions directory.
+  #
+  def extensions_dir: () -> untyped
+
+  private
+
+  def find_full_gem_path: () -> untyped
+
+  public
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - full_gem_path()
+  # -->
+  # The full path to the gem (install path + full name).
+  #
+  # TODO: This is duplicated with #gem_dir. Eventually either of them should be
+  # deprecated.
+  #
+  def full_gem_path: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - full_name()
+  # -->
+  # Returns the full name (name-version) of this Gem.  Platform information is
+  # included (name-version-platform) if it is specified and not the default Ruby
+  # platform.
+  #
+  def full_name: () -> ::String
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - full_name_with_location()
+  # -->
+  # Returns the full name of this Gem (see `Gem::BasicSpecification#full_name`).
+  # Information about where the gem is installed is also included if not installed
+  # in the default GEM_HOME.
+  #
+  def full_name_with_location: () -> (::String | untyped)
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - full_require_paths()
+  # -->
+  # Full paths in the gem to add to `$LOAD_PATH` when this gem is activated.
+  #
+  def full_require_paths: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - datadir()
+  # -->
+  # The path to the data directory for this gem.
+  #
+  def datadir: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - to_fullpath(path)
+  # -->
+  # Full path of the target library file. If the file is not in this gem, return
+  # nil.
+  #
+  def to_fullpath: (untyped path) -> (untyped | nil)
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - gem_dir()
+  # -->
+  # Returns the full path to this spec's gem directory. eg:
+  # /usr/local/lib/ruby/1.8/gems/mygem-1.0
+  #
+  # TODO: This is duplicated with #full_gem_path. Eventually either of them should
+  # be deprecated.
+  #
+  def gem_dir: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - gems_dir()
+  # -->
+  # Returns the full path to the gems directory containing this spec's gem
+  # directory. eg: /usr/local/lib/ruby/1.8/gems
+  #
+  def gems_dir: () -> untyped
+
+  def internal_init: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - name()
+  # -->
+  # Name of the gem
+  #
+  def name: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - platform()
+  # -->
+  # Platform of the gem
+  #
+  def platform: () -> untyped
+
+  def raw_require_paths: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - require_paths()
+  # -->
+  # Paths in the gem to add to `$LOAD_PATH` when this gem is activated.
+  #
+  # See also #require_paths=
+  #
+  # If you have an extension you do not need to add `"ext"` to the require path,
+  # the extension build process will copy the extension files into "lib" for you.
+  #
+  # The default value is `"lib"`
+  #
+  # Usage:
+  #
+  #     # If all library files are in the root directory...
+  #     spec.require_path = '.'
+  #
+  def require_paths: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - source_paths()
+  # -->
+  # Returns the paths to the source files for use with analysis and documentation
+  # tools.  These paths are relative to full_gem_path.
+  #
+  def source_paths: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - matches_for_glob(glob)
+  # -->
+  # Return all files in this gem that match for `glob`.
+  #
+  def matches_for_glob: (untyped glob) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - plugins()
+  # -->
+  # Returns the list of plugins in this spec.
+  #
+  def plugins: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - lib_dirs_glob()
+  # -->
+  # Returns a string usable in Dir.glob to match all requirable paths for this
+  # spec.
+  #
+  def lib_dirs_glob: () -> ::String
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - to_spec()
+  # -->
+  # Return a Gem::Specification from this gem
+  #
+  def to_spec: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - version()
+  # -->
+  # Version of the gem
+  #
+  def version: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - stubbed?()
+  # -->
+  # Whether this specification is stubbed - i.e. we have information about the gem
+  # from a stub line, without having to evaluate the entire gemspec file.
+  #
+  def stubbed?: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - this()
+  # -->
+  #
+  def this: () -> self
+
+  private
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - have_extensions?()
+  # -->
+  #
+  def have_extensions?: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/basic_specification.rb
+  #   - have_file?(file, suffixes)
+  # -->
+  #
+  def have_file?: (untyped file, untyped suffixes) -> (true | untyped)
+end
diff --git a/rbs/fills/rubygems/0/errors.rbs b/rbs/fills/rubygems/0/errors.rbs
new file mode 100644
index 000000000..34b97fcf1
--- /dev/null
+++ b/rbs/fills/rubygems/0/errors.rbs
@@ -0,0 +1,364 @@
+# <!-- rdoc-file=lib/rubygems.rb -->
+# RubyGems is the Ruby standard for publishing and managing third party
+# libraries.
+#
+# For user documentation, see:
+#
+# *   `gem help` and `gem help [command]`
+# *   [RubyGems User Guide](https://guides.rubygems.org/)
+# *   [Frequently Asked Questions](https://guides.rubygems.org/faqs)
+#
+# For gem developer documentation see:
+#
+# *   [Creating Gems](https://guides.rubygems.org/make-your-own-gem)
+# *   Gem::Specification
+# *   Gem::Version for version dependency notes
+#
+# Further RubyGems documentation can be found at:
+#
+# *   [RubyGems Guides](https://guides.rubygems.org)
+# *   [RubyGems API](https://www.rubydoc.info/github/rubygems/rubygems) (also
+#     available from `gem server`)
+#
+# ## RubyGems Plugins
+#
+# RubyGems will load plugins in the latest version of each installed gem or
+# $LOAD_PATH.  Plugins must be named 'rubygems_plugin' (.rb, .so, etc) and
+# placed at the root of your gem's #require_path.  Plugins are installed at a
+# special location and loaded on boot.
+#
+# For an example plugin, see the [Graph gem](https://github.com/seattlerb/graph)
+# which adds a `gem graph` command.
+#
+# ## RubyGems Defaults, Packaging
+#
+# RubyGems defaults are stored in lib/rubygems/defaults.rb.  If you're packaging
+# RubyGems or implementing Ruby you can change RubyGems' defaults.
+#
+# For RubyGems packagers, provide lib/rubygems/defaults/operating_system.rb and
+# override any defaults from lib/rubygems/defaults.rb.
+#
+# For Ruby implementers, provide lib/rubygems/defaults/#{RUBY_ENGINE}.rb and
+# override any defaults from lib/rubygems/defaults.rb.
+#
+# If you need RubyGems to perform extra work on install or uninstall, your
+# defaults override file can set pre/post install and uninstall hooks. See
+# Gem::pre_install, Gem::pre_uninstall, Gem::post_install, Gem::post_uninstall.
+#
+# ## Bugs
+#
+# You can submit bugs to the [RubyGems bug
+# tracker](https://github.com/rubygems/rubygems/issues) on GitHub
+#
+# ## Credits
+#
+# RubyGems is currently maintained by Eric Hodel.
+#
+# RubyGems was originally developed at RubyConf 2003 by:
+#
+# *   Rich Kilmer  -- rich(at)infoether.com
+# *   Chad Fowler  -- chad(at)chadfowler.com
+# *   David Black  -- dblack(at)wobblini.net
+# *   Paul Brannan -- paul(at)atdesk.com
+# *   Jim Weirich   -- jim(at)weirichhouse.org
+#
+# Contributors:
+#
+# *   Gavin Sinclair     -- gsinclair(at)soyabean.com.au
+# *   George Marrows     -- george.marrows(at)ntlworld.com
+# *   Dick Davies        -- rasputnik(at)hellooperator.net
+# *   Mauricio Fernandez -- batsman.geo(at)yahoo.com
+# *   Simon Strandgaard  -- neoneye(at)adslhome.dk
+# *   Dave Glasser       -- glasser(at)mit.edu
+# *   Paul Duncan        -- pabs(at)pablotron.org
+# *   Ville Aine         -- vaine(at)cs.helsinki.fi
+# *   Eric Hodel         -- drbrain(at)segment7.net
+# *   Daniel Berger      -- djberg96(at)gmail.com
+# *   Phil Hagelberg     -- technomancy(at)gmail.com
+# *   Ryan Davis         -- ryand-ruby(at)zenspider.com
+# *   Evan Phoenix       -- evan(at)fallingsnow.net
+# *   Steve Klabnik      -- steve(at)steveklabnik.com
+#
+# (If your name is missing, PLEASE let us know!)
+#
+# ## License
+#
+# See
+# [LICENSE.txt](https://github.com/rubygems/rubygems/blob/master/LICENSE.txt)
+# for permissions.
+#
+# Thanks!
+#
+# -The RubyGems Team
+#
+# <!-- rdoc-file=lib/rubygems/deprecate.rb -->
+# Provides 3 methods for declaring when something is going away.
+#
+# +deprecate(name, repl, year, month)+:
+#     Indicate something may be removed on/after a certain date.
+#
+# +rubygems_deprecate(name, replacement=:none)+:
+#     Indicate something will be removed in the next major RubyGems version,
+#     and (optionally) a replacement for it.
+#
+# `rubygems_deprecate_command`:
+#     Indicate a RubyGems command (in +lib/rubygems/commands/*.rb+) will be
+#     removed in the next RubyGems version.
+#
+# Also provides `skip_during` for temporarily turning off deprecation warnings.
+# This is intended to be used in the test suite, so deprecation warnings don't
+# cause test failures if you need to make sure stderr is otherwise empty.
+#
+# Example usage of `deprecate` and `rubygems_deprecate`:
+#
+#     class Legacy
+#       def self.some_class_method
+#         # ...
+#       end
+#
+#       def some_instance_method
+#         # ...
+#       end
+#
+#       def some_old_method
+#         # ...
+#       end
+#
+#       extend Gem::Deprecate
+#       deprecate :some_instance_method, "X.z", 2011, 4
+#       rubygems_deprecate :some_old_method, "Modern#some_new_method"
+#
+#       class << self
+#         extend Gem::Deprecate
+#         deprecate :some_class_method, :none, 2011, 4
+#       end
+#     end
+#
+# Example usage of `rubygems_deprecate_command`:
+#
+#     class Gem::Commands::QueryCommand < Gem::Command
+#       extend Gem::Deprecate
+#       rubygems_deprecate_command
+#
+#       # ...
+#     end
+#
+# Example usage of `skip_during`:
+#
+#     class TestSomething < Gem::Testcase
+#       def test_some_thing_with_deprecations
+#         Gem::Deprecate.skip_during do
+#           actual_stdout, actual_stderr = capture_output do
+#             Gem.something_deprecated
+#           end
+#           assert_empty actual_stdout
+#           assert_equal(expected, actual_stderr)
+#         end
+#       end
+#     end
+#
+module Gem
+  # <!-- rdoc-file=lib/rubygems/errors.rb -->
+  # Raised when RubyGems is unable to load or activate a gem.  Contains the name
+  # and version requirements of the gem that either conflicts with already
+  # activated gems or that RubyGems is otherwise unable to activate.
+  #
+  class LoadError < ::LoadError
+    # <!-- rdoc-file=lib/rubygems/errors.rb -->
+    # Name of gem
+    #
+    attr_accessor name: untyped
+
+    # <!-- rdoc-file=lib/rubygems/errors.rb -->
+    # Version requirement of gem
+    #
+    attr_accessor requirement: untyped
+  end
+
+  # <!-- rdoc-file=lib/rubygems/errors.rb -->
+  # Raised when trying to activate a gem, and that gem does not exist on the
+  # system.  Instead of rescuing from this class, make sure to rescue from the
+  # superclass Gem::LoadError to catch all types of load errors.
+  #
+  class MissingSpecError < Gem::LoadError
+    @name: untyped
+
+    @requirement: untyped
+
+    @extra_message: untyped
+
+    # <!--
+    #   rdoc-file=lib/rubygems/errors.rb
+    #   - new(name, requirement, extra_message=nil)
+    # -->
+    #
+    def initialize: (untyped name, untyped requirement, ?untyped? extra_message) -> void
+
+    def message: () -> untyped
+
+    private
+
+    # <!--
+    #   rdoc-file=lib/rubygems/errors.rb
+    #   - build_message()
+    # -->
+    #
+    def build_message: () -> ::String
+  end
+
+  # <!-- rdoc-file=lib/rubygems/errors.rb -->
+  # Raised when trying to activate a gem, and the gem exists on the system, but
+  # not the requested version. Instead of rescuing from this class, make sure to
+  # rescue from the superclass Gem::LoadError to catch all types of load errors.
+  #
+  class MissingSpecVersionError < MissingSpecError
+    @specs: untyped
+
+    attr_reader specs: untyped
+
+    # <!--
+    #   rdoc-file=lib/rubygems/errors.rb
+    #   - new(name, requirement, specs)
+    # -->
+    #
+    def initialize: (untyped name, untyped requirement, untyped specs) -> void
+
+    private
+
+    # <!--
+    #   rdoc-file=lib/rubygems/errors.rb
+    #   - build_message()
+    # -->
+    #
+    def build_message: () -> ::String
+  end
+
+  # <!-- rdoc-file=lib/rubygems/errors.rb -->
+  # Raised when there are conflicting gem specs loaded
+  #
+  class ConflictError < LoadError
+    @target: untyped
+
+    @conflicts: untyped
+
+    @name: untyped
+
+    # <!-- rdoc-file=lib/rubygems/errors.rb -->
+    # A Hash mapping conflicting specifications to the dependencies that caused the
+    # conflict
+    #
+    attr_reader conflicts: untyped
+
+    # <!-- rdoc-file=lib/rubygems/errors.rb -->
+    # The specification that had the conflict
+    #
+    attr_reader target: untyped
+
+    # <!--
+    #   rdoc-file=lib/rubygems/errors.rb
+    #   - new(target, conflicts)
+    # -->
+    #
+    def initialize: (untyped target, untyped conflicts) -> void
+  end
+
+  class ErrorReason
+  end
+
+  # <!-- rdoc-file=lib/rubygems/errors.rb -->
+  # Generated when trying to lookup a gem to indicate that the gem was found, but
+  # that it isn't usable on the current platform.
+  #
+  # fetch and install read these and report them to the user to aid in figuring
+  # out why a gem couldn't be installed.
+  #
+  class PlatformMismatch < ErrorReason
+    @name: untyped
+
+    @version: untyped
+
+    @platforms: untyped
+
+    # <!-- rdoc-file=lib/rubygems/errors.rb -->
+    # the name of the gem
+    #
+    attr_reader name: untyped
+
+    # <!-- rdoc-file=lib/rubygems/errors.rb -->
+    # the version
+    #
+    attr_reader version: untyped
+
+    # <!-- rdoc-file=lib/rubygems/errors.rb -->
+    # The platforms that are mismatched
+    #
+    attr_reader platforms: untyped
+
+    # <!--
+    #   rdoc-file=lib/rubygems/errors.rb
+    #   - new(name, version)
+    # -->
+    #
+    def initialize: (untyped name, untyped version) -> void
+
+    # <!--
+    #   rdoc-file=lib/rubygems/errors.rb
+    #   - add_platform(platform)
+    # -->
+    # append a platform to the list of mismatched platforms.
+    #
+    # Platforms are added via this instead of injected via the constructor so that
+    # we can loop over a list of mismatches and just add them rather than perform
+    # some kind of calculation mismatch summary before creation.
+    #
+    def add_platform: (untyped platform) -> untyped
+
+    # <!--
+    #   rdoc-file=lib/rubygems/errors.rb
+    #   - wordy()
+    # -->
+    # A wordy description of the error.
+    #
+    def wordy: () -> untyped
+  end
+
+  # <!-- rdoc-file=lib/rubygems/errors.rb -->
+  # An error that indicates we weren't able to fetch some data from a source
+  #
+  class SourceFetchProblem < ErrorReason
+    @source: untyped
+
+    @error: untyped
+
+    # <!--
+    #   rdoc-file=lib/rubygems/errors.rb
+    #   - new(source, error)
+    # -->
+    # Creates a new SourceFetchProblem for the given `source` and `error`.
+    #
+    def initialize: (untyped source, untyped error) -> void
+
+    # <!-- rdoc-file=lib/rubygems/errors.rb -->
+    # The source that had the fetch problem.
+    #
+    attr_reader source: untyped
+
+    # <!-- rdoc-file=lib/rubygems/errors.rb -->
+    # The fetch error which is an Exception subclass.
+    #
+    attr_reader error: untyped
+
+    # <!--
+    #   rdoc-file=lib/rubygems/errors.rb
+    #   - wordy()
+    # -->
+    # An English description of the error.
+    #
+    def wordy: () -> ::String
+
+    # <!-- rdoc-file=lib/rubygems/errors.rb -->
+    # The fetch error which is an Exception subclass.
+    #
+    alias exception error
+  end
+end
diff --git a/rbs/fills/rubygems/0/spec_fetcher.rbs b/rbs/fills/rubygems/0/spec_fetcher.rbs
new file mode 100644
index 000000000..9914dc85d
--- /dev/null
+++ b/rbs/fills/rubygems/0/spec_fetcher.rbs
@@ -0,0 +1,107 @@
+# <!-- rdoc-file=lib/rubygems/spec_fetcher.rb -->
+# SpecFetcher handles metadata updates from remote gem repositories.
+#
+class Gem::SpecFetcher
+  self.@fetcher: untyped
+
+  @sources: untyped
+
+  @update_cache: untyped
+
+  @specs: untyped
+
+  @latest_specs: untyped
+
+  @prerelease_specs: untyped
+
+  @caches: untyped
+
+  @fetcher: untyped
+
+  include Gem::UserInteraction
+
+  include Gem::Text
+
+  attr_reader latest_specs: untyped
+
+  attr_reader sources: untyped
+
+  attr_reader specs: untyped
+
+  attr_reader prerelease_specs: untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/spec_fetcher.rb
+  #   - fetcher()
+  # -->
+  # Default fetcher instance.  Use this instead of ::new to reduce object
+  # allocation.
+  #
+  def self.fetcher: () -> untyped
+
+  def self.fetcher=: (untyped fetcher) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/spec_fetcher.rb
+  #   - new(sources = nil)
+  # -->
+  # Creates a new SpecFetcher.  Ordinarily you want to use the default fetcher
+  # from Gem::SpecFetcher::fetcher which uses the Gem.sources.
+  #
+  # If you need to retrieve specifications from a different `source`, you can send
+  # it as an argument.
+  #
+  def initialize: (?untyped? sources) -> void
+
+  # <!--
+  #   rdoc-file=lib/rubygems/spec_fetcher.rb
+  #   - search_for_dependency(dependency, matching_platform=true)
+  # -->
+  # Find and fetch gem name tuples that match `dependency`.
+  #
+  # If `matching_platform` is false, gems for all platforms are returned.
+  #
+  def search_for_dependency: (untyped dependency, ?bool matching_platform) -> ::Array[untyped]
+
+  # <!--
+  #   rdoc-file=lib/rubygems/spec_fetcher.rb
+  #   - detect(type=:complete) { |tup| ... }
+  # -->
+  # Return all gem name tuples who's names match `obj`
+  #
+  def detect: (?::Symbol type) { (untyped) -> untyped } -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/spec_fetcher.rb
+  #   - spec_for_dependency(dependency, matching_platform=true)
+  # -->
+  # Find and fetch specs that match `dependency`.
+  #
+  # If `matching_platform` is false, gems for all platforms are returned.
+  #
+  def spec_for_dependency: (untyped dependency, ?bool matching_platform) -> ::Array[untyped]
+
+  # <!--
+  #   rdoc-file=lib/rubygems/spec_fetcher.rb
+  #   - suggest_gems_from_name(gem_name, type = :latest, num_results = 5)
+  # -->
+  # Suggests gems based on the supplied `gem_name`. Returns an array of
+  # alternative gem names.
+  #
+  def suggest_gems_from_name: (untyped gem_name, ?::Symbol type, ?::Integer num_results) -> (::Array[untyped] | untyped)
+
+  # <!--
+  #   rdoc-file=lib/rubygems/spec_fetcher.rb
+  #   - available_specs(type)
+  # -->
+  # Returns a list of gems available for each source in Gem::sources.
+  #
+  # `type` can be one of 3 values: :released   => Return the list of all released
+  # specs :complete   => Return the list of all specs :latest     => Return the
+  # list of only the highest version of each gem :prerelease => Return the list of
+  # all prerelease only specs
+  #
+  def available_specs: (untyped type) -> ::Array[untyped]
+
+  def tuples_for: (untyped source, untyped type, ?bool gracefully_ignore) -> untyped
+end
diff --git a/rbs/fills/rubygems/0/specification.rbs b/rbs/fills/rubygems/0/specification.rbs
new file mode 100644
index 000000000..ff51ef0b1
--- /dev/null
+++ b/rbs/fills/rubygems/0/specification.rbs
@@ -0,0 +1,1753 @@
+# <!-- rdoc-file=lib/rubygems/specification.rb -->
+# The Specification class contains the information for a gem.  Typically defined
+# in a .gemspec file or a Rakefile, and looks like this:
+#
+#     Gem::Specification.new do |s|
+#       s.name        = 'example'
+#       s.version     = '0.1.0'
+#       s.licenses    = ['MIT']
+#       s.summary     = "This is an example!"
+#       s.description = "Much longer explanation of the example!"
+#       s.authors     = ["Ruby Coder"]
+#       s.email       = 'rubycoder@example.com'
+#       s.files       = ["lib/example.rb"]
+#       s.homepage    = 'https://rubygems.org/gems/example'
+#       s.metadata    = { "source_code_uri" => "https://github.com/example/example" }
+#     end
+#
+# Starting in RubyGems 2.0, a Specification can hold arbitrary metadata.  See
+# #metadata for restrictions on the format and size of metadata items you may
+# add to a specification.
+#
+class Gem::Specification < Gem::BasicSpecification
+  @@required_attributes: untyped
+
+  @@default_value: untyped
+
+  @@attributes: untyped
+
+  @@array_attributes: untyped
+
+  @@nil_attributes: untyped
+
+  @@non_nil_attributes: untyped
+
+  @@dirs: untyped
+
+  self.@load_cache: untyped
+
+  self.@load_cache_mutex: untyped
+
+  self.@specification_record: untyped
+
+  self.@unresolved_deps: untyped
+
+  @removed_method_calls: untyped
+
+  # DO NOT CHANGE TO ||= ! This is not a normal accessor. (yes, it sucks)
+  # DOC: Why isn't it normal? Why does it suck? How can we fix this?
+  @files: untyped
+
+  @authors: untyped
+
+  @licenses: untyped
+
+  @original_platform: untyped
+
+  @new_platform: untyped
+
+  @platform: untyped
+
+  @require_paths: untyped
+
+  @executables: untyped
+
+  @extensions: untyped
+
+  @extra_rdoc_files: untyped
+
+  @installed_by_version: untyped
+
+  @rdoc_options: untyped
+
+  @required_ruby_version: untyped
+
+  @required_rubygems_version: untyped
+
+  @requirements: untyped
+
+  @test_files: untyped
+
+  @extensions_dir: untyped
+
+  @activated: untyped
+
+  @loaded: untyped
+
+  @bin_dir: untyped
+
+  @cache_dir: untyped
+
+  @cache_file: untyped
+
+  @date: untyped
+
+  @dependencies: untyped
+
+  @description: untyped
+
+  @doc_dir: untyped
+
+  @full_name: untyped
+
+  @gems_dir: untyped
+
+  @has_rdoc: untyped
+
+  @base_dir: untyped
+
+  @loaded_from: untyped
+
+  @ri_dir: untyped
+
+  @spec_dir: untyped
+
+  @spec_file: untyped
+
+  @summary: untyped
+
+  @test_suite_file: untyped
+
+  @version: untyped
+
+  extend Gem::Deprecate
+
+  # <!-- rdoc-file=lib/rubygems/specification.rb -->
+  # The version number of a specification that does not specify one (i.e. RubyGems
+  # 0.7 or earlier).
+  #
+  NONEXISTENT_SPECIFICATION_VERSION: -1
+
+  CURRENT_SPECIFICATION_VERSION: 4
+
+  SPECIFICATION_VERSION_HISTORY: { -1 => ::Array["(RubyGems versions up to and including 0.7 did not have versioned specifications)"], 1 => ::Array["Deprecated \"test_suite_file\" in favor of the new, but equivalent, \"test_files\"" | "\"test_file=x\" is a shortcut for \"test_files=[x]\""], 2 => ::Array["Added \"required_rubygems_version\"" | "Now forward-compatible with future versions"], 3 => ::Array["Added Fixnum validation to the specification_version"], 4 => ::Array["Added sandboxed freeform metadata to the specification version."] }
+
+  MARSHAL_FIELDS: { -1 => 16, 1 => 16, 2 => 16, 3 => 17, 4 => 18 }
+
+  TODAY: untyped
+
+  VALID_NAME_PATTERN: ::Regexp
+
+  # rubocop:disable Style/MutableConstant
+  INITIALIZE_CODE_FOR_DEFAULTS: ::Hash[untyped, untyped]
+
+  # Sentinel object to represent "not found" stubs
+  NOT_FOUND: untyped
+
+  # Tracking removed method calls to warn users during build time.
+  REMOVED_METHODS: ::Array[:rubyforge_project= | :mark_version]
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - removed_method_calls()
+  # -->
+  #
+  def removed_method_calls: () -> untyped
+
+  # <!-- rdoc-file=lib/rubygems/specification.rb -->
+  # This gem's name.
+  #
+  # Usage:
+  #
+  #     spec.name = 'rake'
+  #
+  attr_accessor name: String
+
+  # <!-- rdoc-file=lib/rubygems/specification.rb -->
+  # This gem's version.
+  #
+  # The version string can contain numbers and periods, such as `1.0.0`. A gem is
+  # a 'prerelease' gem if the version has a letter in it, such as `1.0.0.pre`.
+  #
+  # Usage:
+  #
+  #     spec.version = '0.4.1'
+  #
+  attr_reader version: String
+
+  # <!-- rdoc-file=lib/rubygems/specification.rb -->
+  # A short summary of this gem's description.  Displayed in `gem list -d`.
+  #
+  # The #description should be more detailed than the summary.
+  #
+  # Usage:
+  #
+  #     spec.summary = "This is a small summary of my gem"
+  #
+  attr_reader summary: untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - files()
+  # -->
+  # Files included in this gem.  You cannot append to this accessor, you must
+  # assign to it.
+  #
+  # Only add files you can require to this list, not directories, etc.
+  #
+  # Directories are automatically stripped from this list when building a gem,
+  # other non-files cause an error.
+  #
+  # Usage:
+  #
+  #     require 'rake'
+  #     spec.files = FileList['lib/**/*.rb',
+  #                           'bin/*',
+  #                           '[A-Z]*'].to_a
+  #
+  #     # or without Rake...
+  #     spec.files = Dir['lib/**/*.rb'] + Dir['bin/*']
+  #     spec.files += Dir['[A-Z]*']
+  #     spec.files.reject! { |fn| fn.include? "CVS" }
+  #
+  def files: () -> Enumerable[String]
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - authors=(value)
+  # -->
+  # A list of authors for this gem.
+  #
+  # Alternatively, a single author can be specified by assigning a string to
+  # `spec.author`
+  #
+  # Usage:
+  #
+  #     spec.authors = ['John Jones', 'Mary Smith']
+  #
+  def authors=: (untyped value) -> untyped
+
+  # <!-- rdoc-file=lib/rubygems/specification.rb -->
+  # The version of Ruby required by this gem
+  #
+  # Usage:
+  #
+  #     spec.required_ruby_version = '>= 2.7.0'
+  #
+  attr_reader required_ruby_version: untyped
+
+  # <!-- rdoc-file=lib/rubygems/specification.rb -->
+  # A long description of this gem
+  #
+  # The description should be more detailed than the summary but not excessively
+  # long.  A few paragraphs is a recommended length with no examples or
+  # formatting.
+  #
+  # Usage:
+  #
+  #     spec.description = <<-EOF
+  #       Rake is a Make-like program implemented in Ruby. Tasks and
+  #       dependencies are specified in standard Ruby syntax.
+  #     EOF
+  #
+  attr_reader description: untyped
+
+  # <!-- rdoc-file=lib/rubygems/specification.rb -->
+  # A contact email address (or addresses) for this gem
+  #
+  # Usage:
+  #
+  #     spec.email = 'john.jones@example.com'
+  #     spec.email = ['jack@example.com', 'jill@example.com']
+  #
+  attr_accessor email: untyped
+
+  # <!-- rdoc-file=lib/rubygems/specification.rb -->
+  # The URL of this gem's home page
+  #
+  # Usage:
+  #
+  #     spec.homepage = 'https://github.com/ruby/rake'
+  #
+  attr_accessor homepage: untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - license=(o)
+  # -->
+  # The license for this gem.
+  #
+  # The license must be no more than 64 characters.
+  #
+  # This should just be the name of your license. The full text of the license
+  # should be inside of the gem (at the top level) when you build it.
+  #
+  # The simplest way is to specify the standard SPDX ID https://spdx.org/licenses/
+  # for the license. Ideally, you should pick one that is OSI (Open Source
+  # Initiative) http://opensource.org/licenses/alphabetical approved.
+  #
+  # The most commonly used OSI-approved licenses are MIT and Apache-2.0. GitHub
+  # also provides a license picker at http://choosealicense.com/.
+  #
+  # You can also use a custom license file along with your gemspec and specify a
+  # LicenseRef-<idstring>, where idstring is the name of the file containing the
+  # license text.
+  #
+  # You should specify a license for your gem so that people know how they are
+  # permitted to use it and any restrictions you're placing on it.  Not specifying
+  # a license means all rights are reserved; others have no right to use the code
+  # for any purpose.
+  #
+  # You can set multiple licenses with #licenses=
+  #
+  # Usage:
+  #     spec.license = 'MIT'
+  #
+  def license=: (untyped o) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - licenses=(licenses)
+  # -->
+  # The license(s) for the library.
+  #
+  # Each license must be a short name, no more than 64 characters.
+  #
+  # This should just be the name of your license. The full text of the license
+  # should be inside of the gem when you build it.
+  #
+  # See #license= for more discussion
+  #
+  # Usage:
+  #     spec.licenses = ['MIT', 'GPL-2.0']
+  #
+  def licenses=: (untyped licenses) -> untyped
+
+  # <!-- rdoc-file=lib/rubygems/specification.rb -->
+  # The metadata holds extra data for this gem that may be useful to other
+  # consumers and is settable by gem authors.
+  #
+  # Metadata items have the following restrictions:
+  #
+  # *   The metadata must be a Hash object
+  # *   All keys and values must be Strings
+  # *   Keys can be a maximum of 128 bytes and values can be a maximum of 1024
+  #     bytes
+  # *   All strings must be UTF-8, no binary data is allowed
+  #
+  # You can use metadata to specify links to your gem's homepage, codebase,
+  # documentation, wiki, mailing list, issue tracker and changelog.
+  #
+  #     s.metadata = {
+  #       "bug_tracker_uri"   => "https://example.com/user/bestgemever/issues",
+  #       "changelog_uri"     => "https://example.com/user/bestgemever/CHANGELOG.md",
+  #       "documentation_uri" => "https://www.example.info/gems/bestgemever/0.0.1",
+  #       "homepage_uri"      => "https://bestgemever.example.io",
+  #       "mailing_list_uri"  => "https://groups.example.com/bestgemever",
+  #       "source_code_uri"   => "https://example.com/user/bestgemever",
+  #       "wiki_uri"          => "https://example.com/user/bestgemever/wiki"
+  #       "funding_uri"       => "https://example.com/donate"
+  #     }
+  #
+  # These links will be used on your gem's page on rubygems.org and must pass
+  # validation against following regex.
+  #
+  #     %r{\Ahttps?:\/\/([^\s:@]+:[^\s:@]*@)?[A-Za-z\d\-]+(\.[A-Za-z\d\-]+)+\.?(:\d{1,5})?([\/?]\S*)?\z}
+  #
+  attr_accessor metadata: untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - author=(o)
+  # -->
+  # Singular (alternative) writer for #authors
+  #
+  # Usage:
+  #
+  #     spec.author = 'John Jones'
+  #
+  def author=: (untyped o) -> untyped
+
+  # <!-- rdoc-file=lib/rubygems/specification.rb -->
+  # The path in the gem for executable scripts.  Usually 'bin'
+  #
+  # Usage:
+  #
+  #     spec.bindir = 'bin'
+  #
+  attr_accessor bindir: untyped
+
+  # <!-- rdoc-file=lib/rubygems/specification.rb -->
+  # The certificate chain used to sign this gem.  See Gem::Security for details.
+  #
+  attr_accessor cert_chain: untyped
+
+  # <!-- rdoc-file=lib/rubygems/specification.rb -->
+  # A message that gets displayed after the gem is installed.
+  #
+  # Usage:
+  #
+  #     spec.post_install_message = "Thanks for installing!"
+  #
+  attr_accessor post_install_message: untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - platform=(platform)
+  # -->
+  # The platform this gem runs on.
+  #
+  # This is usually Gem::Platform::RUBY or Gem::Platform::CURRENT.
+  #
+  # Most gems contain pure Ruby code; they should simply leave the default value
+  # in place.  Some gems contain C (or other) code to be compiled into a Ruby
+  # "extension".  The gem should leave the default value in place unless the code
+  # will only compile on a certain type of system.  Some gems consist of
+  # pre-compiled code ("binary gems").  It's especially important that they set
+  # the platform attribute appropriately.  A shortcut is to set the platform to
+  # Gem::Platform::CURRENT, which will cause the gem builder to set the platform
+  # to the appropriate value for the system on which the build is being performed.
+  #
+  # If this attribute is set to a non-default value, it will be included in the
+  # filename of the gem when it is built such as: nokogiri-1.6.0-x86-mingw32.gem
+  #
+  # Usage:
+  #
+  #     spec.platform = Gem::Platform.local
+  #
+  def platform=: (untyped platform) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - require_paths=(val)
+  # -->
+  # Paths in the gem to add to `$LOAD_PATH` when this gem is activated. If you
+  # have an extension you do not need to add `"ext"` to the require path, the
+  # extension build process will copy the extension files into "lib" for you.
+  #
+  # The default value is `"lib"`
+  #
+  # Usage:
+  #
+  #     # If all library files are in the root directory...
+  #     spec.require_paths = ['.']
+  #
+  def require_paths=: (untyped val) -> untyped
+
+  # <!-- rdoc-file=lib/rubygems/specification.rb -->
+  # The RubyGems version required by this gem
+  #
+  attr_reader required_rubygems_version: untyped
+
+  # <!-- rdoc-file=lib/rubygems/specification.rb -->
+  # The key used to sign this gem.  See Gem::Security for details.
+  #
+  attr_accessor signing_key: untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - add_development_dependency(gem, *requirements)
+  # -->
+  # Adds a development dependency named `gem` with `requirements` to this gem.
+  #
+  # Usage:
+  #
+  #     spec.add_development_dependency 'example', '~> 1.1', '>= 1.1.4'
+  #
+  # Development dependencies aren't installed by default and aren't activated when
+  # a gem is required.
+  #
+  def add_development_dependency: (untyped gem, *untyped requirements) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - add_dependency(gem, *requirements)
+  # -->
+  #
+  def add_dependency: (untyped gem, *untyped requirements) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - executables()
+  # -->
+  # Executables included in the gem.
+  #
+  # For example, the rake gem has rake as an executable. You don’t specify the
+  # full path (as in bin/rake); all application-style files are expected to be
+  # found in bindir.  These files must be executable Ruby files.  Files that use
+  # bash or other interpreters will not work.
+  #
+  # Executables included may only be ruby scripts, not scripts for other languages
+  # or compiled binaries.
+  #
+  # Usage:
+  #
+  #     spec.executables << 'rake'
+  #
+  def executables: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - extensions()
+  # -->
+  # Extensions to build when installing the gem, specifically the paths to
+  # extconf.rb-style files used to compile extensions.
+  #
+  # These files will be run when the gem is installed, causing the C (or whatever)
+  # code to be compiled on the user’s machine.
+  #
+  # Usage:
+  #
+  #     spec.extensions << 'ext/rmagic/extconf.rb'
+  #
+  # See Gem::Ext::Builder for information about writing extensions for gems.
+  #
+  def extensions: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - extra_rdoc_files()
+  # -->
+  # Extra files to add to RDoc such as README or doc/examples.txt
+  #
+  # When the user elects to generate the RDoc documentation for a gem (typically
+  # at install time), all the library files are sent to RDoc for processing. This
+  # option allows you to have some non-code files included for a more complete set
+  # of documentation.
+  #
+  # Usage:
+  #
+  #     spec.extra_rdoc_files = ['README', 'doc/user-guide.txt']
+  #
+  def extra_rdoc_files: () -> untyped
+
+  def installed_by_version: () -> untyped
+
+  def installed_by_version=: (untyped version) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - rdoc_options()
+  # -->
+  # Specifies the rdoc options to be used when generating API documentation.
+  #
+  # Usage:
+  #
+  #     spec.rdoc_options << '--title' << 'Rake -- Ruby Make' <<
+  #       '--main' << 'README' <<
+  #       '--line-numbers'
+  #
+  def rdoc_options: () -> untyped
+
+  LATEST_RUBY_WITHOUT_PATCH_VERSIONS: untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - required_ruby_version=(req)
+  # -->
+  # The version of Ruby required by this gem.  The ruby version can be specified
+  # to the patch-level:
+  #
+  #     $ ruby -v -e 'p Gem.ruby_version'
+  #     ruby 2.0.0p247 (2013-06-27 revision 41674) [x86_64-darwin12.4.0]
+  #     #<Gem::Version "2.0.0.247">
+  #
+  # Prereleases can also be specified.
+  #
+  # Usage:
+  #
+  #     # This gem will work with 1.8.6 or greater...
+  #     spec.required_ruby_version = '>= 1.8.6'
+  #
+  #     # Only with final releases of major version 2 where minor version is at least 3
+  #     spec.required_ruby_version = '~> 2.3'
+  #
+  #     # Only prereleases or final releases after 2.6.0.preview2
+  #     spec.required_ruby_version = '> 2.6.0.preview2'
+  #
+  #     # This gem will work with 2.3.0 or greater, including major version 3, but lesser than 4.0.0
+  #     spec.required_ruby_version = '>= 2.3', '< 4'
+  #
+  def required_ruby_version=: (untyped req) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - required_rubygems_version=(req)
+  # -->
+  # The RubyGems version required by this gem
+  #
+  def required_rubygems_version=: (untyped req) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - requirements()
+  # -->
+  # Lists the external (to RubyGems) requirements that must be met for this gem to
+  # work.  It's simply information for the user.
+  #
+  # Usage:
+  #
+  #     spec.requirements << 'libmagick, v6.0'
+  #     spec.requirements << 'A good graphics card'
+  #
+  def requirements: () -> untyped
+
+  def test_files=: (untyped files) -> untyped
+
+  # <!-- rdoc-file=lib/rubygems/specification.rb -->
+  # The version of RubyGems used to create this gem.
+  #
+  # Do not set this, it is set automatically when the gem is packaged.
+  #
+  attr_accessor rubygems_version: untyped
+
+  def extensions_dir: () -> untyped
+
+  # <!-- rdoc-file=lib/rubygems/specification.rb -->
+  # True when this gemspec has been activated. This attribute is not persisted.
+  #
+  attr_accessor activated: untyped
+
+  # <!-- rdoc-file=lib/rubygems/specification.rb -->
+  # True when this gemspec has been activated. This attribute is not persisted.
+  #
+  alias activated? activated
+
+  attr_accessor autorequire: untyped
+
+  attr_writer default_executable: untyped
+
+  attr_writer original_platform: untyped
+
+  # <!-- rdoc-file=lib/rubygems/specification.rb -->
+  # The Gem::Specification version of this gemspec.
+  #
+  # Do not set this, it is set automatically when the gem is packaged.
+  #
+  attr_accessor specification_version: untyped
+
+  def self._all: () -> untyped
+
+  def self.clear_load_cache: () -> untyped
+
+  def self.gem_path: () -> untyped
+
+  def self.each_gemspec: (untyped dirs) { (untyped) -> untyped } -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - gemspec_stubs_in(dir, pattern) { |path| ... }
+  # -->
+  #
+  def self.gemspec_stubs_in: (untyped dir, untyped pattern) { (untyped) -> untyped } -> untyped
+
+  def self.each_spec: (untyped dirs) { (untyped) -> untyped } -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - stubs()
+  # -->
+  # Returns a Gem::StubSpecification for every installed gem
+  #
+  def self.stubs: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - default_stubs(pattern = "*.gemspec")
+  # -->
+  # Returns a Gem::StubSpecification for default gems
+  #
+  def self.default_stubs: (?::String pattern) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - stubs_for(name)
+  # -->
+  # Returns a Gem::StubSpecification for installed gem named `name` only returns
+  # stubs that match Gem.platforms
+  #
+  def self.stubs_for: (untyped name) -> untyped
+
+  #
+  # Finds stub specifications matching a pattern from the standard locations,
+  # optionally filtering out specs not matching the current platform
+  #
+  def self.stubs_for_pattern: (untyped pattern, ?bool match_platform) -> untyped
+
+  def self._resort!: (untyped specs) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - load_defaults()
+  # -->
+  # Loads the default specifications. It should be called only once.
+  #
+  def self.load_defaults: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - add_spec(spec)
+  # -->
+  # Adds `spec` to the known specifications, keeping the collection properly
+  # sorted.
+  #
+  def self.add_spec: (untyped spec) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - remove_spec(spec)
+  # -->
+  # Removes `spec` from the known specs.
+  #
+  def self.remove_spec: (untyped spec) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - all()
+  # -->
+  # Returns all specifications. This method is discouraged from use. You probably
+  # want to use one of the Enumerable methods instead.
+  #
+  def self.all: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - all=(specs)
+  # -->
+  # Sets the known specs to `specs`. Not guaranteed to work for you in the future.
+  # Use at your own risk. Caveat emptor. Doomy doom doom. Etc etc.
+  #
+  def self.all=: (untyped specs) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - all_names()
+  # -->
+  # Return full names of all specs in sorted order.
+  #
+  def self.all_names: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - array_attributes()
+  # -->
+  # Return the list of all array-oriented instance variables.
+  #
+  def self.array_attributes: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - attribute_names()
+  # -->
+  # Return the list of all instance variables.
+  #
+  def self.attribute_names: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - dirs()
+  # -->
+  # Return the directories that Specification uses to find specs.
+  #
+  def self.dirs: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - dirs=(dirs)
+  # -->
+  # Set the directories that Specification uses to find specs. Setting this resets
+  # the list of known specs.
+  #
+  def self.dirs=: (untyped dirs) -> untyped
+
+  extend Enumerable[Gem::Specification]
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - each() { |x| ... }
+  # -->
+  # Enumerate every known spec.  See ::dirs= and ::add_spec to set the list of
+  # specs.
+  #
+  def self.each: () { (Gem::Specification) -> untyped } -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - find_all_by_name(name, *requirements)
+  # -->
+  # Returns every spec that matches `name` and optional `requirements`.
+  #
+  def self.find_all_by_name: (untyped name, *untyped requirements) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - find_all_by_full_name(full_name)
+  # -->
+  # Returns every spec that has the given `full_name`
+  #
+  def self.find_all_by_full_name: (untyped full_name) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - find_by_name(name, *requirements)
+  # -->
+  # Find the best specification matching a `name` and `requirements`. Raises if
+  # the dependency doesn't resolve to a valid specification.
+  #
+  def self.find_by_name: (String name, *untyped requirements) -> instance
+
+  #
+  # Find the best specification matching a +full_name+.
+  def self.find_by_full_name: (untyped full_name) -> instance
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - find_by_path(path)
+  # -->
+  # Return the best specification that contains the file matching `path`.
+  #
+  def self.find_by_path: (String path) -> instance
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - find_inactive_by_path(path)
+  # -->
+  # Return the best specification that contains the file matching `path` amongst
+  # the specs that are not activated.
+  #
+  def self.find_inactive_by_path: (untyped path) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - find_active_stub_by_path(path)
+  # -->
+  #
+  def self.find_active_stub_by_path: (untyped path) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - find_in_unresolved(path)
+  # -->
+  # Return currently unresolved specs that contain the file matching `path`.
+  #
+  def self.find_in_unresolved: (untyped path) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - find_in_unresolved_tree(path)
+  # -->
+  # Search through all unresolved deps and sub-dependencies and return specs that
+  # contain the file matching `path`.
+  #
+  def self.find_in_unresolved_tree: (untyped path) -> (untyped | ::Array[untyped])
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - unresolved_specs()
+  # -->
+  #
+  def self.unresolved_specs: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - from_yaml(input)
+  # -->
+  # Special loader for YAML files.  When a Specification object is loaded from a
+  # YAML file, it bypasses the normal Ruby object initialization routine
+  # (#initialize).  This method makes up for that and deals with gems of different
+  # ages.
+  #
+  # `input` can be anything that YAML.load() accepts: String or IO.
+  #
+  def self.from_yaml: (untyped input) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - latest_specs(prerelease = false)
+  # -->
+  # Return the latest specs, optionally including prerelease specs if `prerelease`
+  # is true.
+  #
+  def self.latest_specs: (?bool prerelease) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - latest_spec_for(name)
+  # -->
+  # Return the latest installed spec for gem `name`.
+  #
+  def self.latest_spec_for: (untyped name) -> untyped
+
+  def self._latest_specs: (untyped specs, ?bool prerelease) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - load(file)
+  # -->
+  # Loads Ruby format gemspec from `file`.
+  #
+  def self.load: (untyped file) -> (nil | untyped)
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - non_nil_attributes()
+  # -->
+  # Specification attributes that must be non-nil
+  #
+  def self.non_nil_attributes: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - normalize_yaml_input(input)
+  # -->
+  # Make sure the YAML specification is properly formatted with dashes
+  #
+  def self.normalize_yaml_input: (untyped input) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - outdated()
+  # -->
+  # Return a list of all outdated local gem names.  This method is HEAVY as it
+  # must go fetch specifications from the server.
+  #
+  # Use outdated_and_latest_version if you wish to retrieve the latest remote
+  # version as well.
+  #
+  def self.outdated: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - outdated_and_latest_version() { |local_spec, latest_remote| ... }
+  # -->
+  # Enumerates the outdated local gems yielding the local specification and the
+  # latest remote version.
+  #
+  # This method may take some time to return as it must check each local gem
+  # against the server's index.
+  #
+  def self.outdated_and_latest_version: () ?{ (untyped) -> untyped } -> (untyped | nil)
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - required_attribute?(name)
+  # -->
+  # Is `name` a required attribute?
+  #
+  def self.required_attribute?: (untyped name) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - required_attributes()
+  # -->
+  # Required specification attributes
+  #
+  def self.required_attributes: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - reset()
+  # -->
+  # Reset the list of known specs, running pre and post reset hooks registered in
+  # Gem.
+  #
+  def self.reset: () -> untyped
+
+  def self.specification_record: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - unresolved_deps()
+  # -->
+  # DOC: This method needs documented or nodoc'd
+  #
+  def self.unresolved_deps: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - _load(str)
+  # -->
+  # Load custom marshal format, re-initializing defaults as needed
+  #
+  def self._load: (untyped str) -> untyped
+
+  def <=>: (untyped other) -> untyped
+
+  def ==: (untyped other) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - _dump(limit)
+  # -->
+  # Dump only crucial instance variables.
+  #
+  def _dump: (untyped limit) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - activate()
+  # -->
+  # Activate this spec, registering it as a loaded spec and adding it's lib paths
+  # to $LOAD_PATH. Returns true if the spec was activated, false if it was
+  # previously activated. Freaks out if there are conflicts upon activation.
+  #
+  def activate: () -> (false | true)
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - activate_dependencies()
+  # -->
+  # Activate all unambiguously resolved runtime dependencies of this spec. Add any
+  # ambiguous dependencies to the unresolved list to be resolved later, as needed.
+  #
+  def activate_dependencies: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - abbreviate()
+  # -->
+  # Abbreviate the spec for downloading.  Abbreviated specs are only used for
+  # searching, downloading and related activities and do not need deployment
+  # specific information (e.g. list of files).  So we abbreviate the spec, making
+  # it much smaller for quicker downloads.
+  #
+  def abbreviate: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - sanitize()
+  # -->
+  # Sanitize the descriptive fields in the spec.  Sometimes non-ASCII characters
+  # will garble the site index.  Non-ASCII characters will be replaced by their
+  # XML entity equivalent.
+  #
+  def sanitize: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - sanitize_string(string)
+  # -->
+  # Sanitize a single string.
+  #
+  def sanitize_string: (untyped string) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - add_bindir(executables)
+  # -->
+  # Returns an array with bindir attached to each executable in the `executables`
+  # list
+  #
+  def add_bindir: (untyped executables) -> untyped
+
+  private
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - add_dependency_with_type(dependency, type, requirements)
+  # -->
+  # Adds a dependency on gem `dependency` with type `type` that requires
+  # `requirements`.  Valid types are currently `:runtime` and `:development`.
+  #
+  def add_dependency_with_type: (untyped dependency, untyped type, untyped requirements) -> untyped
+
+  public
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - add_runtime_dependency(gem, *requirements)
+  # -->
+  # Adds a runtime dependency named `gem` with `requirements` to this gem.
+  #
+  # Usage:
+  #
+  #     spec.add_runtime_dependency 'example', '~> 1.1', '>= 1.1.4'
+  #
+  alias add_runtime_dependency add_dependency
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - add_self_to_load_path()
+  # -->
+  # Adds this spec's require paths to LOAD_PATH, in the proper location.
+  #
+  def add_self_to_load_path: () -> (nil | untyped)
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - author()
+  # -->
+  # Singular reader for #authors.  Returns the first author in the list
+  #
+  def author: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - authors()
+  # -->
+  # The list of author names who wrote this gem.
+  #
+  #     spec.authors = ['Chad Fowler', 'Jim Weirich', 'Rich Kilmer']
+  #
+  def authors: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - bin_dir()
+  # -->
+  # Returns the full path to installed gem's bin directory.
+  #
+  # NOTE: do not confuse this with `bindir`, which is just 'bin', not a full path.
+  #
+  def bin_dir: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - bin_file(name)
+  # -->
+  # Returns the full path to an executable named `name` in this gem.
+  #
+  def bin_file: (untyped name) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - build_args()
+  # -->
+  # Returns the build_args used to install the gem
+  #
+  def build_args: () -> (untyped | ::Array[untyped])
+
+  def build_extensions: () -> (nil | untyped)
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - build_info_dir()
+  # -->
+  # Returns the full path to the build info directory
+  #
+  def build_info_dir: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - build_info_file()
+  # -->
+  # Returns the full path to the file containing the build information generated
+  # when the gem was installed
+  #
+  def build_info_file: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - cache_dir()
+  # -->
+  # Returns the full path to the cache directory containing this spec's cached
+  # gem.
+  #
+  def cache_dir: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - cache_file()
+  # -->
+  # Returns the full path to the cached gem for this spec.
+  #
+  def cache_file: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - conflicts()
+  # -->
+  # Return any possible conflicts against the currently loaded specs.
+  #
+  def conflicts: () -> untyped
+
+  def conficts_when_loaded_with?: (untyped list_of_specs) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - has_conflicts?()
+  # -->
+  # Return true if there are possible conflicts against the currently loaded
+  # specs.
+  #
+  def has_conflicts?: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - date()
+  # -->
+  # The date this gem was created.
+  #
+  # If SOURCE_DATE_EPOCH is set as an environment variable, use that to support
+  # reproducible builds; otherwise, default to the current UTC date.
+  #
+  # Details on SOURCE_DATE_EPOCH:
+  # https://reproducible-builds.org/specs/source-date-epoch/
+  #
+  def date: () -> untyped
+
+  DateLike: untyped
+
+  def self.===: (untyped obj) -> untyped
+
+  DateTimeFormat: ::Regexp
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - date=(date)
+  # -->
+  # The date this gem was created
+  #
+  # DO NOT set this, it is set automatically when the gem is packaged.
+  #
+  def date=: (untyped date) -> untyped
+
+  def default_executable: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - default_value(name)
+  # -->
+  # The default value for specification attribute `name`
+  #
+  def default_value: (untyped name) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - dependencies()
+  # -->
+  # A list of Gem::Dependency objects this gem depends on.
+  #
+  # Use #add_dependency or #add_development_dependency to add dependencies to a
+  # gem.
+  #
+  def dependencies: () -> Array[Gem::Dependency]
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - dependent_gems(check_dev=true)
+  # -->
+  # Return a list of all gems that have a dependency on this gemspec.  The list is
+  # structured with entries that conform to:
+  #
+  #     [depending_gem, dependency, [list_of_gems_that_satisfy_dependency]]
+  #
+  def dependent_gems: (?bool check_dev) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - dependent_specs()
+  # -->
+  # Returns all specs that matches this spec's runtime dependencies.
+  #
+  def dependent_specs: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - description=(str)
+  # -->
+  # A detailed description of this gem.  See also #summary
+  #
+  def description=: (untyped str) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - development_dependencies()
+  # -->
+  # List of dependencies that are used for development
+  #
+  def development_dependencies: () -> Array[Gem::Dependency]
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - doc_dir(type = nil)
+  # -->
+  # Returns the full path to this spec's documentation directory.  If `type` is
+  # given it will be appended to the end.  For example:
+  #
+  #     spec.doc_dir      # => "/path/to/gem_repo/doc/a-1"
+  #
+  #     spec.doc_dir 'ri' # => "/path/to/gem_repo/doc/a-1/ri"
+  #
+  def doc_dir: (?untyped? type) -> untyped
+
+  def encode_with: (untyped coder) -> untyped
+
+  def eql?: (untyped other) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - executable()
+  # -->
+  # Singular accessor for #executables
+  #
+  def executable: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - executable=(o)
+  # -->
+  # Singular accessor for #executables
+  #
+  def executable=: (untyped o) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - executables=(value)
+  # -->
+  # Sets executables to `value`, ensuring it is an array.
+  #
+  def executables=: (untyped value) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - extensions=(extensions)
+  # -->
+  # Sets extensions to `extensions`, ensuring it is an array.
+  #
+  def extensions=: (untyped extensions) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - extra_rdoc_files=(files)
+  # -->
+  # Sets extra_rdoc_files to `files`, ensuring it is an array.
+  #
+  def extra_rdoc_files=: (untyped files) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - file_name()
+  # -->
+  # The default (generated) file name of the gem.  See also #spec_name.
+  #
+  #     spec.file_name # => "example-1.0.gem"
+  #
+  def file_name: () -> ::String
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - files=(files)
+  # -->
+  # Sets files to `files`, ensuring it is an array.
+  #
+  def files=: (untyped files) -> untyped
+
+  private
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - find_all_satisfiers(dep) { |spec| ... }
+  # -->
+  # Finds all gems that satisfy `dep`
+  #
+  def find_all_satisfiers: (untyped dep) { (untyped) -> untyped } -> untyped
+
+  public
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - for_cache()
+  # -->
+  # Creates a duplicate spec without large blobs that aren't used at runtime.
+  #
+  def for_cache: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - full_name()
+  # -->
+  #
+  def full_name: () -> untyped
+
+  def gem_dir: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - gems_dir()
+  # -->
+  #
+  def gems_dir: () -> untyped
+
+  def has_rdoc: () -> true
+
+  def has_rdoc=: (untyped ignored) -> untyped
+
+  alias has_rdoc? has_rdoc
+
+  def has_unit_tests?: () -> untyped
+
+  # :stopdoc:
+  alias has_test_suite? has_unit_tests?
+
+  def hash: () -> untyped
+
+  def init_with: (untyped coder) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - new(name = nil, version = nil) { |self| ... }
+  # -->
+  # Specification constructor. Assigns the default values to the attributes and
+  # yields itself for further initialization.  Optionally takes `name` and
+  # `version`.
+  #
+  def initialize: (?untyped? name, ?untyped? version) ?{ (untyped) -> untyped } -> void
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - initialize_copy(other_spec)
+  # -->
+  # Duplicates array_attributes from `other_spec` so state isn't shared.
+  #
+  def initialize_copy: (untyped other_spec) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - base_dir()
+  # -->
+  #
+  def base_dir: () -> untyped
+
+  private
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - invalidate_memoized_attributes()
+  # -->
+  # Expire memoized instance variables that can incorrectly generate, replace or
+  # miss files due changes in certain attributes used to compute them.
+  #
+  def invalidate_memoized_attributes: () -> untyped
+
+  public
+
+  def inspect: () -> (untyped | ::String)
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - lib_files()
+  # -->
+  # Files in the Gem under one of the require_paths
+  #
+  def lib_files: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - license()
+  # -->
+  # Singular accessor for #licenses
+  #
+  def license: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - licenses()
+  # -->
+  # Plural accessor for setting licenses
+  #
+  # See #license= for details
+  #
+  def licenses: () -> untyped
+
+  def internal_init: () -> untyped
+
+  def method_missing: (untyped sym, *untyped a) { (?) -> untyped } -> (nil | untyped)
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - missing_extensions?()
+  # -->
+  # Is this specification missing its extensions?  When this returns true you
+  # probably want to build_extensions
+  #
+  def missing_extensions?: () -> (false | true)
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - normalize()
+  # -->
+  # Normalize the list of files so that:
+  # *   All file lists have redundancies removed.
+  # *   Files referenced in the extra_rdoc_files are included in the package file
+  #     list.
+  #
+  def normalize: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - name_tuple()
+  # -->
+  # Return a NameTuple that represents this Specification
+  #
+  def name_tuple: () -> untyped
+
+  def original_name: () -> ::String
+
+  def original_platform: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - platform()
+  # -->
+  # The platform this gem runs on.  See Gem::Platform for details.
+  #
+  def platform: () -> untyped
+
+  def pretty_print: (untyped q) -> untyped
+
+  private
+
+  def check_version_conflict: (untyped other) -> (nil | untyped)
+
+  public
+
+  def raise_if_conflicts: () -> (untyped | nil)
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - rdoc_options=(options)
+  # -->
+  # Sets rdoc_options to `value`, ensuring it is an array.
+  #
+  def rdoc_options=: (untyped options) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - require_path()
+  # -->
+  # Singular accessor for #require_paths
+  #
+  def require_path: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - require_path=(path)
+  # -->
+  # Singular accessor for #require_paths
+  #
+  def require_path=: (untyped path) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - requirements=(req)
+  # -->
+  # Set requirements to `req`, ensuring it is an array.
+  #
+  def requirements=: (untyped req) -> untyped
+
+  def respond_to_missing?: (untyped m, ?bool include_private) -> false
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - ri_dir()
+  # -->
+  # Returns the full path to this spec's ri directory.
+  #
+  def ri_dir: () -> untyped
+
+  private
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - ruby_code(obj)
+  # -->
+  # Return a string containing a Ruby code representation of the given object.
+  #
+  def ruby_code: (untyped obj) -> untyped
+
+  public
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - runtime_dependencies()
+  # -->
+  # List of dependencies that will automatically be activated at runtime.
+  #
+  def runtime_dependencies: () -> untyped
+
+  private
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - same_attributes?(spec)
+  # -->
+  # True if this gem has the same attributes as `other`.
+  #
+  def same_attributes?: (untyped spec) -> untyped
+
+  public
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - satisfies_requirement?(dependency)
+  # -->
+  # Checks if this specification meets the requirement of `dependency`.
+  #
+  def satisfies_requirement?: (untyped dependency) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - sort_obj()
+  # -->
+  # Returns an object you can use to sort specifications in #sort_by.
+  #
+  def sort_obj: () -> ::Array[untyped]
+
+  def source: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - spec_dir()
+  # -->
+  # Returns the full path to the directory containing this spec's gemspec file.
+  # eg: /usr/local/lib/ruby/gems/1.8/specifications
+  #
+  def spec_dir: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - spec_file()
+  # -->
+  # Returns the full path to this spec's gemspec file. eg:
+  # /usr/local/lib/ruby/gems/1.8/specifications/mygem-1.0.gemspec
+  #
+  def spec_file: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - spec_name()
+  # -->
+  # The default name of the gemspec.  See also #file_name
+  #
+  #     spec.spec_name # => "example-1.0.gemspec"
+  #
+  def spec_name: () -> ::String
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - summary=(str)
+  # -->
+  # A short summary of this gem's description.
+  #
+  def summary=: (untyped str) -> untyped
+
+  def test_file: () -> untyped
+
+  def test_file=: (untyped file) -> untyped
+
+  def test_files: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - to_ruby()
+  # -->
+  # Returns a Ruby code representation of this specification, such that it can be
+  # eval'ed and reconstruct the same specification later.  Attributes that still
+  # have their default values are omitted.
+  #
+  def to_ruby: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - to_ruby_for_cache()
+  # -->
+  # Returns a Ruby lighter-weight code representation of this specification, used
+  # for indexing only.
+  #
+  # See #to_ruby.
+  #
+  def to_ruby_for_cache: () -> untyped
+
+  def to_s: () -> ::String
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - to_spec()
+  # -->
+  # Returns self
+  #
+  def to_spec: () -> self
+
+  def to_yaml: (?::Hash[untyped, untyped] opts) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - traverse(trail = [], visited = {}, &block)
+  # -->
+  # Recursively walk dependencies of this spec, executing the `block` for each
+  # hop.
+  #
+  def traverse: (?untyped trail, ?::Hash[untyped, untyped] visited) { (?) -> untyped } -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - validate(packaging = true, strict = false)
+  # -->
+  # Checks that the specification contains all required fields, and does a very
+  # basic sanity check.
+  #
+  # Raises InvalidSpecificationException if the spec does not pass the checks..
+  #
+  def validate: (?bool packaging, ?bool strict) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - keep_only_files_and_directories()
+  # -->
+  #
+  def keep_only_files_and_directories: () -> untyped
+
+  def validate_for_resolution: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - validate_metadata()
+  # -->
+  #
+  def validate_metadata: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - validate_dependencies()
+  # -->
+  #
+  def validate_dependencies: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - validate_permissions()
+  # -->
+  #
+  def validate_permissions: () -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - version=(version)
+  # -->
+  # Set the version to `version`, potentially also setting
+  # required_rubygems_version if `version` indicates it is a prerelease.
+  #
+  def version=: (untyped version) -> (nil | untyped)
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - stubbed?()
+  # -->
+  #
+  def stubbed?: () -> false
+
+  def yaml_initialize: (untyped tag, untyped vals) -> untyped
+
+  # <!--
+  #   rdoc-file=lib/rubygems/specification.rb
+  #   - reset_nil_attributes_to_default()
+  # -->
+  # Reset nil attributes to their default values to make the spec valid
+  #
+  def reset_nil_attributes_to_default: () -> nil
+
+  def flatten_require_paths: () -> (nil | untyped)
+
+  def raw_require_paths: () -> untyped
+end
diff --git a/rbs/fills/tuple.rbs b/rbs/fills/tuple/tuple.rbs
similarity index 100%
rename from rbs/fills/tuple.rbs
rename to rbs/fills/tuple/tuple.rbs
diff --git a/rbs_collection.yaml b/rbs_collection.yaml
index 66e30ecfe..898239cac 100644
--- a/rbs_collection.yaml
+++ b/rbs_collection.yaml
@@ -1,15 +1,15 @@
 # Download sources
 sources:
+  - type: local
+    name: shims
+    path: sig/shims
+
   - type: git
     name: ruby/gem_rbs_collection
     remote: https://github.com/ruby/gem_rbs_collection.git
     revision: main
     repo_dir: gems
 
-# You can specify local directories as sources also.
-# - type: local
-#   path: path/to/your/local/repository
-
 # A directory to install the downloaded RBSs
 path: .gem_rbs_collection
 
diff --git a/sig/shims/ast/0/node.rbs b/sig/shims/ast/0/node.rbs
new file mode 100644
index 000000000..fab1a4de0
--- /dev/null
+++ b/sig/shims/ast/0/node.rbs
@@ -0,0 +1,5 @@
+module ::AST
+  class Node
+     def children: () -> [self, Integer, String, Symbol, nil]
+  end
+end
diff --git a/sig/shims/ast/2.4/.rbs_meta.yaml b/sig/shims/ast/2.4/.rbs_meta.yaml
new file mode 100644
index 000000000..f361b3112
--- /dev/null
+++ b/sig/shims/ast/2.4/.rbs_meta.yaml
@@ -0,0 +1,9 @@
+---
+name: ast
+version: '2.4'
+source:
+  type: git
+  name: ruby/gem_rbs_collection
+  revision: c604d278dd6c14a1bb6cf0c0051af643b268a981
+  remote: https://github.com/ruby/gem_rbs_collection.git
+  repo_dir: gems
diff --git a/sig/shims/ast/2.4/ast.rbs b/sig/shims/ast/2.4/ast.rbs
new file mode 100644
index 000000000..e7fb8975e
--- /dev/null
+++ b/sig/shims/ast/2.4/ast.rbs
@@ -0,0 +1,73 @@
+module AST
+  interface _ToAst
+    def to_ast: () -> Node
+  end
+
+  interface _ToSym
+    def to_sym: () -> Symbol
+  end
+
+  class Node
+    public
+
+    attr_reader children: Array[Node]
+    attr_reader hash: String
+    attr_reader type: Symbol
+
+    alias + concat
+
+    alias << append
+
+    def ==: (untyped other) -> bool
+
+    def append: (untyped element) -> self
+
+    alias clone dup
+
+    def concat: (_ToA[untyped] array) -> self
+
+    def dup: () -> self
+
+    def eql?: (untyped other) -> bool
+
+    def inspect: (?Integer indent) -> String
+
+    alias to_a children
+
+    def to_ast: () -> self
+
+    alias to_s to_sexp
+
+    def to_sexp: (?Integer indent) -> String
+
+    def to_sexp_array: () -> Array[untyped]
+
+    def updated: (?_ToSym? `type`, ?_ToA[untyped]? children, ?Hash[Symbol, untyped]? properties) -> self
+
+    private
+
+    def initialize: (_ToSym `type`, ?_ToA[untyped]? children, ?Hash[Symbol, untyped] properties) -> void
+
+    alias original_dup dup
+  end
+
+  class Processor
+    include Mixin
+
+    module Mixin
+      public
+
+      def handler_missing: (Node node) -> Node?
+
+      def process: (_ToAst? node) -> Node?
+
+      def process_all: (Array[_ToAst] nodes) -> Array[Node]
+    end
+  end
+
+  module Sexp
+    public
+
+    def s: (_ToSym `type`, *untyped children) -> Node
+  end
+end
diff --git a/sig/shims/parser/3.2.0.1/builders/default.rbs b/sig/shims/parser/3.2.0.1/builders/default.rbs
new file mode 100644
index 000000000..861a9e371
--- /dev/null
+++ b/sig/shims/parser/3.2.0.1/builders/default.rbs
@@ -0,0 +1,195 @@
+# frozen_string_literal: true
+
+module Parser
+  ##
+  # Default AST builder. Uses {AST::Node}s.
+  #
+  module Builders
+    class Default
+      ##
+      # AST compatibility attribute; since `-> {}` is not semantically
+      # equivalent to `lambda {}`, all new code should set this attribute
+      # to true.
+      #
+      # If set to false (the default), `-> {}` is emitted as
+      # `s(:block, s(:send, nil, :lambda), s(:args), nil)`.
+      #
+      # If set to true, `-> {}` is emitted as
+      # `s(:block, s(:lambda), s(:args), nil)`.
+      #
+      # @return [Boolean]
+      attr_accessor self.emit_lambda: bool
+
+      ##
+      # AST compatibility attribute; block arguments of `m { |a| }` are
+      # not semantically equivalent to block arguments of `m { |a,| }` or `m { |a, b| }`,
+      # all new code should set this attribute to true.
+      #
+      # If set to false (the default), arguments of `m { |a| }` are emitted as
+      # `s(:args, s(:arg, :a))`.
+      #
+      # If set to true, arguments of `m { |a| }` are emitted as
+      # `s(:args, s(:procarg0, :a)).
+      #
+      # @return [Boolean]
+      attr_accessor self.emit_procarg0: bool
+
+      ##
+      # AST compatibility attribute; locations of `__ENCODING__` are not the same
+      # as locations of `Encoding::UTF_8` causing problems during rewriting,
+      # all new code should set this attribute to true.
+      #
+      # If set to false (the default), `__ENCODING__` is emitted as
+      # ` s(:const, s(:const, nil, :Encoding), :UTF_8)`.
+      #
+      # If set to true, `__ENCODING__` is emitted as
+      # `s(:__ENCODING__)`.
+      #
+      # @return [Boolean]
+      attr_accessor self.emit_encoding: bool
+
+      ##
+      # AST compatibility attribute; indexed assignment, `x[] = 1`, is not
+      # semantically equivalent to calling the method directly, `x.[]=(1)`.
+      # Specifically, in the former case, the expression's value is always 1,
+      # and in the latter case, the expression's value is the return value
+      # of the `[]=` method.
+      #
+      # If set to false (the default), `self[1]` is emitted as
+      # `s(:send, s(:self), :[], s(:int, 1))`, and `self[1] = 2` is
+      # emitted as `s(:send, s(:self), :[]=, s(:int, 1), s(:int, 2))`.
+      #
+      # If set to true, `self[1]` is emitted as
+      # `s(:index, s(:self), s(:int, 1))`, and `self[1] = 2` is
+      # emitted as `s(:indexasgn, s(:self), s(:int, 1), s(:int, 2))`.
+      #
+      # @return [Boolean]
+      attr_accessor self.emit_index: bool
+
+      ##
+      # AST compatibility attribute; causes a single non-mlhs
+      # block argument to be wrapped in s(:procarg0).
+      #
+      # If set to false (the default), block arguments `|a|` are emitted as
+      # `s(:args, s(:procarg0, :a))`
+      #
+      # If set to true, block arguments `|a|` are emitted as
+      # `s(:args, s(:procarg0, s(:arg, :a))`
+      #
+      # @return [Boolean]
+      attr_accessor self.emit_arg_inside_procarg0: bool
+
+      ##
+      # AST compatibility attribute; arguments forwarding initially
+      # didn't have support for leading arguments
+      # (i.e. `def m(a, ...); end` was a syntax error). However, Ruby 3.0
+      # added support for any number of arguments in front of the `...`.
+      #
+      # If set to false (the default):
+      #   1. `def m(...) end` is emitted as
+      #      s(:def, :m, s(:forward_args), nil)
+      #   2. `def m(a, b, ...) end` is emitted as
+      #      s(:def, :m,
+      #        s(:args, s(:arg, :a), s(:arg, :b), s(:forward_arg)))
+      #
+      # If set to true it uses a single format:
+      #   1. `def m(...) end` is emitted as
+      #      s(:def, :m, s(:args, s(:forward_arg)))
+      #   2. `def m(a, b, ...) end` is emitted as
+      #      s(:def, :m, s(:args, s(:arg, :a), s(:arg, :b), s(:forward_arg)))
+      #
+      # It does't matter that much on 2.7 (because there can't be any leading arguments),
+      # but on 3.0 it should be better enabled to use a single AST format.
+      #
+      # @return [Boolean]
+      attr_accessor self.emit_forward_arg: bool
+
+      ##
+      # AST compatibility attribute; Starting from Ruby 2.7 keyword arguments
+      # of method calls that are passed explicitly as a hash (i.e. with curly braces)
+      # are treated as positional arguments and Ruby 2.7 emits a warning on such method
+      # call. Ruby 3.0 given an ArgumentError.
+      #
+      # If set to false (the default) the last hash argument is emitted as `hash`:
+      #
+      # ```
+      # (send nil :foo
+      #   (hash
+      #     (pair
+      #       (sym :bar)
+      #       (int 42))))
+      # ```
+      #
+      # If set to true it is emitted as `kwargs`:
+      #
+      # ```
+      # (send nil :foo
+      #   (kwargs
+      #     (pair
+      #       (sym :bar)
+      #       (int 42))))
+      # ```
+      #
+      # Note that `kwargs` node is just a replacement for `hash` argument,
+      # so if there's are multiple arguments (or a `kwsplat`) all of them
+      # are wrapped into `kwargs` instead of `hash`:
+      #
+      # ```
+      # (send nil :foo
+      #   (kwargs
+      #     (pair
+      #       (sym :a)
+      #       (int 42))
+      #     (kwsplat
+      #       (send nil :b))
+      #     (pair
+      #       (sym :c)
+      #       (int 10))))
+      # ```
+      attr_accessor self.emit_kwargs: bool
+
+      ##
+      # AST compatibility attribute; Starting from 3.0 Ruby returns
+      # true/false from single-line pattern matching with `in` keyword.
+      #
+      # Before 3.0 there was an exception if given value doesn't match pattern.
+      #
+      # NOTE: This attribute affects only Ruby 2.7 grammar.
+      # 3.0 grammar always emits `match_pattern`/`match_pattern_p`
+      #
+      # If compatibility attribute set to false `foo in bar` is emitted as `in_match`:
+      #
+      # ```
+      # (in-match
+      #   (send nil :foo)
+      #   (match-var :bar))
+      # ```
+      #
+      # If set to true it's emitted as `match_pattern_p`:
+      # ```
+      # (match-pattern-p
+      #   (send nil :foo)
+      #   (match-var :bar))
+      # ```
+      attr_accessor self.emit_match_pattern: bool
+
+      ##
+      # If set to true (the default), `__FILE__` and `__LINE__` are transformed to
+      # literal nodes. For example, `s(:str, "lib/foo.rb")` and `s(:int, 10)`.
+      #
+      # If set to false, `__FILE__` and `__LINE__` are emitted as-is,
+      # i.e. as `s(:__FILE__)` and `s(:__LINE__)` nodes.
+      #
+      # Source maps are identical in both cases.
+      #
+      # @return [Boolean]
+      attr_accessor emit_file_line_as_literals: bool
+
+      def value: (untyped token) -> untyped
+
+      def string_value: (untyped token) -> String
+
+      def loc: (untyped token) -> untyped
+    end
+  end
+end
diff --git a/sig/shims/parser/3.2.0.1/manifest.yaml b/sig/shims/parser/3.2.0.1/manifest.yaml
new file mode 100644
index 000000000..f00038381
--- /dev/null
+++ b/sig/shims/parser/3.2.0.1/manifest.yaml
@@ -0,0 +1,7 @@
+# manifest.yaml describes dependencies which do not appear in the gemspec.
+# If this gem includes such dependencies, comment-out the following lines and
+# declare the dependencies.
+# If all dependencies appear in the gemspec, you should remove this file.
+#
+dependencies:
+  - name: ast
diff --git a/sig/shims/parser/3.2.0.1/parser.rbs b/sig/shims/parser/3.2.0.1/parser.rbs
new file mode 100644
index 000000000..065fcf5ca
--- /dev/null
+++ b/sig/shims/parser/3.2.0.1/parser.rbs
@@ -0,0 +1,199 @@
+module Parser
+  CurrentRuby: Parser::Base
+
+  class SyntaxError < StandardError
+  end
+  class UnknownEncodingInMagicComment < StandardError
+  end
+
+  class Base < Racc::Parser
+    def version: -> Integer
+    def self.parse: (String string, ?String file, ?Integer line) -> Parser::AST::Node?
+    def self.parse_with_comments: (String string, ?String file, ?Integer line) -> [Parser::AST::Node?, Array[Source::Comment]]
+    def parse: (Parser::Source::Buffer source_buffer) -> Parser::AST::Node?
+  end
+
+  class Ruby18 < Base
+  end
+  class Ruby19 < Base
+  end
+  class Ruby20 < Base
+  end
+  class Ruby21 < Base
+  end
+  class Ruby22 < Base
+  end
+  class Ruby23 < Base
+  end
+  class Ruby24 < Base
+  end
+  class Ruby25 < Base
+  end
+  class Ruby26 < Base
+  end
+  class Ruby27 < Base
+  end
+  class Ruby30 < Base
+  end
+  class Ruby31 < Base
+  end
+  class Ruby32 < Base
+  end
+  class Ruby33 < Base
+  end
+
+  module AST
+    class Node < ::AST::Node
+      attr_reader location: Source::Map
+      alias loc location
+    end
+
+    class Processor
+      module Mixin
+        def process: (Node? node) ->  Node?
+      end
+
+      include Mixin
+    end
+  end
+
+  module Source
+    class Range
+      attr_reader source_buffer: Buffer
+      attr_reader begin_pos: Integer
+      attr_reader end_pos: Integer
+      def begin: () -> Range
+      def end: () -> Range
+      def size: () -> Integer
+      alias length size
+      def line: () -> Integer
+      alias first_line line
+      def column: () -> Integer
+      def last_line: () -> Integer
+      def last_column: () -> Integer
+      def column_range: () -> ::Range[Integer]
+      def source_line: () -> String
+      def source: () -> String
+      def with: (?begin_pos: Integer, ?end_pos: Integer) -> Range
+      def adjust: (?begin_pos: Integer, ?end_pos: Integer) -> Range
+      def resize: (Integer new_size) -> Range
+      def join: (Range other) -> Range
+      def intersect: (Range other) -> Range?
+      def disjoint?: (Range other) -> bool
+      def overlaps?: (Range other) -> bool
+      def contains?: (Range other) -> bool
+      def contained?: (Range other) -> bool
+      def crossing?: (Range other) -> bool
+      def empty?: () -> bool
+    end
+
+    ##
+    # A buffer with source code. {Buffer} contains the source code itself,
+    # associated location information (name and first line), and takes care
+    # of encoding.
+    #
+    # A source buffer is immutable once populated.
+    #
+    # @!attribute [r] name
+    #  Buffer name. If the buffer was created from a file, the name corresponds
+    #  to relative path to the file.
+    #  @return [String] buffer name
+    #
+    # @!attribute [r] first_line
+    #  First line of the buffer, 1 by default.
+    #  @return [Integer] first line
+    #
+    # @api public
+    #
+    class Buffer
+      attr_reader name: String
+      attr_reader first_line: Integer
+
+      def self.recognize_encoding: (String) -> Encoding
+      def self.reencode_string: (String) -> String
+
+      def initialize: (untyped name, ?Integer first_line, ?source: untyped) -> void
+      def read: () -> self
+      def source: () -> String
+      def source=: (String) -> String
+      def raw_source: (String) -> String
+      def decompose_position: (Integer) -> [Integer, Integer]
+      def source_lines: () -> Array[String]
+      def source_line: (Integer) -> String
+      def line_range: (Integer) -> ::Range[Integer]
+      def source_range: () -> ::Range[Integer]
+      def last_line: () -> Integer
+    end
+
+    class TreeRewriter
+      def replace: (Range range, String content) -> self
+      def remove: (Range range) -> self
+      def insert_before: (Range range, String content) -> self
+      def insert_after: (Range range, String content) -> self
+    end
+
+    class Map
+      attr_reader node: AST::Node | nil
+      attr_reader expression: Range
+      def line: () -> Integer
+      def first_line: () -> Integer
+      def last_line: () -> Integer
+      def column: () -> Integer
+      def last_column: () -> Integer
+    end
+
+    class Map::Collection < Map
+      attr_reader begin: Range?
+      attr_reader end: Range?
+    end
+
+    class Map::Condition < Map
+      attr_reader keyword: Range
+      attr_reader begin: Range?
+      attr_reader else: Range?
+      attr_reader end: Range
+    end
+
+    class Map::Heredoc < Map
+      attr_reader heredoc_body: Range
+      attr_reader heredoc_end: Range
+    end
+
+    class Map::Keyword < Map
+      attr_reader keyword: Range
+      attr_reader begin: Range?
+      attr_reader end: Range?
+    end
+
+    class Map::MethodDefinition < Map
+      attr_reader keyword: Range
+      attr_reader operator: Range?
+      attr_reader name: Range?
+      attr_reader end: Range?
+      attr_reader assignment: Range?
+    end
+
+    class Map::Operator < Map
+      attr_reader operator: Range?
+    end
+
+    class Map::Send < Map
+      attr_reader dot: Range?
+      attr_reader selector: Range
+      attr_reader operator: Range?
+      attr_reader begin: Range?
+      attr_reader end: Range?
+    end
+
+    class Map::Ternary < Map
+      attr_reader question: Range?
+      attr_reader colon: Range
+    end
+
+    class Comment
+      attr_reader text: String
+      attr_reader location: Map
+      alias loc location
+    end
+  end
+end
diff --git a/sig/shims/parser/3.2.0.1/polyfill.rbs b/sig/shims/parser/3.2.0.1/polyfill.rbs
new file mode 100644
index 000000000..2e8c12487
--- /dev/null
+++ b/sig/shims/parser/3.2.0.1/polyfill.rbs
@@ -0,0 +1,4 @@
+module Racc
+  class Parser
+  end
+end
diff --git a/sig/shims/thor/1.2.0.1/.rbs_meta.yaml b/sig/shims/thor/1.2.0.1/.rbs_meta.yaml
new file mode 100644
index 000000000..27c2fb2e4
--- /dev/null
+++ b/sig/shims/thor/1.2.0.1/.rbs_meta.yaml
@@ -0,0 +1,9 @@
+---
+name: thor
+version: '1.2'
+source:
+  type: git
+  name: ruby/gem_rbs_collection
+  revision: 98541aabafdf403b16ebae6fe4060d18bee75e93
+  remote: https://github.com/ruby/gem_rbs_collection.git
+  repo_dir: gems
diff --git a/sig/shims/thor/1.2.0.1/manifest.yaml b/sig/shims/thor/1.2.0.1/manifest.yaml
new file mode 100644
index 000000000..a0cb4d149
--- /dev/null
+++ b/sig/shims/thor/1.2.0.1/manifest.yaml
@@ -0,0 +1,7 @@
+# manifest.yaml describes dependencies which do not appear in the gemspec.
+# If this gem includes such dependencies, comment-out the following lines and
+# declare the dependencies.
+# If all dependencies appear in the gemspec, you should remove this file.
+#
+# dependencies:
+#   - name: pathname
diff --git a/sig/shims/thor/1.2.0.1/thor.rbs b/sig/shims/thor/1.2.0.1/thor.rbs
new file mode 100644
index 000000000..2247507e7
--- /dev/null
+++ b/sig/shims/thor/1.2.0.1/thor.rbs
@@ -0,0 +1,17 @@
+class Thor
+  class Group
+  end
+
+  module Actions
+    class CreateFile
+    end
+
+    def create_file: (String destination, String data, ?verbose: bool) -> String
+                   | (String destination, ?verbose: bool) { () -> String } -> String
+  end
+
+  class Error
+  end
+
+  def self.start: (Array[String] given_args, ?Hash[Symbol, untyped] config) -> void
+end
diff --git a/solargraph.gemspec b/solargraph.gemspec
index e6bb9394a..ca39ebd30 100755
--- a/solargraph.gemspec
+++ b/solargraph.gemspec
@@ -11,7 +11,10 @@ Gem::Specification.new do |s|
   s.authors     = ["Fred Snyder"]
   s.email       = 'admin@castwide.com'
   s.files       = Dir.chdir(File.expand_path('..', __FILE__)) do
-    `git ls-files -z`.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
+    # @sg-ignore Need backtick support
+    # @type [String]
+    all_files = `git ls-files -z`
+    all_files.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
   end
   s.homepage    = 'https://solargraph.org'
   s.license     = 'MIT'
@@ -23,6 +26,7 @@ Gem::Specification.new do |s|
 
   s.required_ruby_version = '>= 3.0'
 
+  s.add_runtime_dependency 'ast', '~> 2.4.3'
   s.add_runtime_dependency 'backport', '~> 1.2'
   s.add_runtime_dependency 'benchmark', '~> 0.4'
   s.add_runtime_dependency 'bundler', '~> 2.0'
@@ -33,11 +37,12 @@ Gem::Specification.new do |s|
   s.add_runtime_dependency 'logger', '~> 1.6'
   s.add_runtime_dependency 'observer', '~> 0.1'
   s.add_runtime_dependency 'ostruct', '~> 0.6'
+  s.add_runtime_dependency 'open3', '~> 0.2.1'
   s.add_runtime_dependency 'parser', '~> 3.0'
   s.add_runtime_dependency 'prism', '~> 1.4'
   s.add_runtime_dependency 'rbs', ['>= 3.6.1', '<= 4.0.0.dev.4']
   s.add_runtime_dependency 'reverse_markdown', '~> 3.0'
-  s.add_runtime_dependency 'rubocop', '~> 1.76'
+  s.add_runtime_dependency 'sord', '~> 7.0'
   s.add_runtime_dependency 'thor', '~> 1.0'
   s.add_runtime_dependency 'tilt', '~> 2.0'
   s.add_runtime_dependency 'yard', '~> 0.9', '>= 0.9.24'
@@ -48,6 +53,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'public_suffix', '~> 3.1'
   s.add_development_dependency 'rake', '~> 13.2'
   s.add_development_dependency 'rspec', '~> 3.5'
+  s.add_development_dependency 'rspec-time-guard', '~> 0.2.0'
   s.add_development_dependency 'rubocop-rake', '~> 0.7'
   s.add_development_dependency 'rubocop-rspec', '~> 3.6'
   s.add_development_dependency 'rubocop-yard', '~> 1.0'
diff --git a/spec/api_map/api_map_method_spec.rb b/spec/api_map/api_map_method_spec.rb
new file mode 100644
index 000000000..389646124
--- /dev/null
+++ b/spec/api_map/api_map_method_spec.rb
@@ -0,0 +1,171 @@
+# frozen_string_literal: true
+
+require 'tmpdir'
+
+describe Solargraph::ApiMap do
+  let(:api_map) { described_class.new }
+  let(:bench) do
+    Solargraph::Bench.new(external_requires: external_requires, workspace: Solargraph::Workspace.new('.'))
+  end
+  let(:external_requires) { [] }
+
+  before do
+    api_map.catalog bench
+  end
+
+  describe '.load_with_cache' do
+    it 'loads the API map with cache', time_limit_seconds: 120 do
+      Solargraph::PinCache.uncache_core
+
+      output = Dir.mktmpdir do |dir|
+        capture_both do
+          described_class.load_with_cache(dir)
+        end
+      end
+
+      expect(output).to include('aching RBS pins for Ruby core')
+    end
+  end
+
+  describe '#qualify' do
+    let(:external_requires) { ['yaml'] }
+
+    it 'resolves YAML to Psych' do
+      expect(api_map.qualify('YAML', '')).to eq('Psych')
+    end
+
+    it 'resolves constants used to alias namespaces' do
+      map = Solargraph::SourceMap.load_string(%(
+        class Foo
+          def bing; end
+        end
+
+        module Bar
+          Baz = ::Foo
+        end
+    ))
+      api_map.index map.pins
+      fqns = api_map.qualify('Bar::Baz')
+      expect(fqns).to eq('Foo')
+    end
+
+    it 'understands alias namespaces resolving types' do
+      source = Solargraph::Source.load_string(%(
+        class Foo
+          # @return [Symbol]
+          def bing; end
+        end
+
+        module Bar
+          Baz = ::Foo
+        end
+
+        a = Bar::Baz.new.bing
+        a
+        Bar::Baz
+      ), 'test.rb')
+
+      api_map = described_class.new.map(source)
+
+      clip = api_map.clip_at('test.rb', [11, 8])
+      expect(clip.infer.to_s).to eq('Symbol')
+    end
+
+    it 'understands nested alias namespaces to nested classes resolving types' do
+      source = Solargraph::Source.load_string(%(
+        module A
+          class Foo
+            # @return [Symbol]
+            def bing; end
+          end
+        end
+
+        module Bar
+          Baz = A::Foo
+        end
+
+        a = Bar::Baz.new.bing
+        a
+      ), 'test.rb')
+
+      api_map = described_class.new.map(source)
+
+      clip = api_map.clip_at('test.rb', [13, 8])
+      expect(clip.infer.to_s).to eq('Symbol')
+    end
+
+    it 'understands nested alias namespaces resolving types' do
+      source = Solargraph::Source.load_string(%(
+        module Bar
+          module A
+            class Foo
+              # @return [Symbol]
+              def bing; :bingo; end
+            end
+          end
+        end
+
+        module Bar
+          Foo = A::Foo
+        end
+
+        a = Bar::Foo.new.bing
+        a
+      ), 'test.rb')
+
+      api_map = described_class.new.map(source)
+
+      clip = api_map.clip_at('test.rb', [15, 8])
+      expect(clip.infer.to_s).to eq('Symbol')
+    end
+
+    it 'understands includes using nested alias namespaces resolving types' do
+      source = Solargraph::Source.load_string(%(
+        module Foo
+          # @return [Symbol]
+          def bing; :yay; end
+        end
+
+        module Bar
+          Baz = Foo
+        end
+
+        class B
+          include Foo
+        end
+
+        a = B.new.bing
+        a
+      ), 'test.rb')
+
+      api_map = described_class.new.map(source)
+
+      clip = api_map.clip_at('test.rb', [15, 8])
+      expect(clip.infer.to_s).to eq('Symbol')
+    end
+  end
+
+  describe '#get_method_stack', time_limit_seconds: 240 do
+    let(:out) { StringIO.new }
+    let(:api_map) { described_class.load_with_cache(Dir.pwd, out) }
+
+    context 'with stdlib that has vital dependencies' do
+      let(:external_requires) { ['yaml'] }
+
+      let(:method_stack) { api_map.get_method_stack('YAML', 'safe_load', scope: :class) }
+
+      it 'handles the YAML gem aliased to Psych' do
+        expect(method_stack).not_to be_empty
+      end
+    end
+
+    context 'with thor' do
+      let(:external_requires) { ['thor'] }
+      let(:method_stack) { api_map.get_method_stack('Thor', 'desc', scope: :class) }
+
+      it 'handles finding Thor.desc' do
+        expect(method_stack).not_to be_empty
+      end
+    end
+  end
+end
diff --git a/spec/api_map/index_spec.rb b/spec/api_map/index_spec.rb
new file mode 100644
index 000000000..8afb74759
--- /dev/null
+++ b/spec/api_map/index_spec.rb
@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+describe Solargraph::ApiMap::Index do
+  subject(:output_pins) { described_class.new(input_pins).pins }
+
+  describe '#map_overrides' do
+    let(:foo_class) do
+      Solargraph::Pin::Namespace.new(name: 'Foo')
+    end
+
+    let(:foo_initialize) do
+      init = Solargraph::Pin::Method.new(name: 'initialize',
+                                         scope: :instance,
+                                         parameters: [],
+                                         closure: foo_class)
+      # no return type specified
+      param = Solargraph::Pin::Parameter.new(name: 'bar',
+                                             closure: init)
+      init.parameters << param
+      init
+    end
+
+    let(:foo_new) do
+      init = Solargraph::Pin::Method.new(name: 'new',
+                                         scope: :class,
+                                         parameters: [],
+                                         closure: foo_class)
+      # no return type specified
+      param = Solargraph::Pin::Parameter.new(name: 'bar',
+                                             closure: init)
+      init.parameters << param
+      init
+    end
+
+    let(:foo_override) do
+      Solargraph::Pin::Reference::Override.from_comment('Foo#initialize',
+                                                        '@param [String] bar')
+    end
+
+    let(:input_pins) do
+      [
+        foo_initialize,
+        foo_new,
+        foo_override
+      ]
+    end
+
+    it 'has a docstring to process on override' do
+      expect(foo_override.docstring.tags).to be_empty
+    end
+
+    it 'overrides .new method' do
+      method_pin = output_pins.find { |pin| pin.path == 'Foo.new' }
+      first_parameter = method_pin.parameters.first
+      expect(first_parameter.return_type.tag).to eq('String')
+    end
+
+    it 'overrides #initialize method in signature' do
+      method_pin = output_pins.find { |pin| pin.path == 'Foo#initialize' }
+      first_parameter = method_pin.parameters.first
+      expect(first_parameter.return_type.tag).to eq('String')
+    end
+  end
+end
diff --git a/spec/api_map_spec.rb b/spec/api_map_spec.rb
index c95d4d8ec..cdeed30d3 100755
--- a/spec/api_map_spec.rb
+++ b/spec/api_map_spec.rb
@@ -1,12 +1,16 @@
+# frozen_string_literal: true
+
 require 'tmpdir'
 
 describe Solargraph::ApiMap do
+  # avoid performance hit of doing this many times
+  # rubocop:disable RSpec/InstanceVariable
   before :all do
-    @api_map = Solargraph::ApiMap.new
+    @api_map = described_class.load_with_cache(Dir.pwd, nil)
   end
 
   it 'returns core methods' do
-    pins = @api_map.get_methods('String')
+    pins = @api_map.get_methods('String') # rubocop:disable RSpec/InstanceVariable
     expect(pins.map(&:path)).to include('String#upcase')
   end
 
@@ -193,7 +197,7 @@ def prot
   end
 
   it 'adds Object instance methods to duck types' do
-    api_map = Solargraph::ApiMap.new
+    api_map = described_class.new
     type = Solargraph::ComplexType.parse('#foo')
     pins = api_map.get_complex_type_methods(type)
     expect(pins.any? { |p| p.namespace == 'BasicObject' }).to be(true)
@@ -434,14 +438,14 @@ class Sup
   xit 'understands tuples inherit from regular arrays' do
     method_pins = @api_map.get_method_stack("Array(1, 2, 'a')", 'include?')
     method_pin = method_pins.first
-    expect(method_pin).to_not be_nil
+    expect(method_pin).not_to be_nil
     expect(method_pin.path).to eq('Array#include?')
     parameter_type = method_pin.signatures.first.parameters.first.return_type
     expect(parameter_type.rooted_tags).to eq("1, 2, 'a'")
   end
 
   it 'loads workspaces from directories' do
-    api_map = Solargraph::ApiMap.load('spec/fixtures/workspace')
+    api_map = described_class.load('spec/fixtures/workspace')
     expect(api_map.source_map(File.absolute_path('spec/fixtures/workspace/app.rb'))).to be_a(Solargraph::SourceMap)
   end
 
@@ -531,7 +535,7 @@ module Includer
     expect(fqns).to eq('Foo::Bar')
   end
 
-  it 'handles multiple type parameters without losing cache coherence' do
+  it 'understands type parameters' do
     tag = @api_map.qualify('Array<String>')
     expect(tag).to eq('Array<String>')
     tag = @api_map.qualify('Array<Integer>')
@@ -755,18 +759,18 @@ def bar; end
   end
 
   it 'can qualify "Boolean"' do
-    api_map = Solargraph::ApiMap.new
+    api_map = described_class.new
     expect(api_map.qualify('Boolean')).to eq('Boolean')
   end
 
   it 'knows that true is a "subtype" of Boolean' do
-    api_map = Solargraph::ApiMap.new
+    api_map = described_class.new
     expect(api_map.super_and_sub?('Boolean', 'true')).to be(true)
   end
 
   it 'knows that false is a "subtype" of Boolean' do
-    api_map = Solargraph::ApiMap.new
-    expect(api_map.super_and_sub?('Boolean', 'true')).to be(true)
+    api_map = described_class.new
+    expect(api_map.super_and_sub?('Boolean', 'false')).to be(true)
   end
 
   it 'resolves aliases for YARD methods' do
@@ -781,7 +785,7 @@ class Foo
         alias baz foo
       end
     )).pins
-    # api_map = Solargraph::ApiMap.new(pins: yard_pins + source_pins)
+    # api_map = described_class.new(pins: yard_pins + source_pins)
     @api_map.index yard_pins + source_pins
     baz = @api_map.get_method_stack('Foo', 'baz').first
     expect(baz).to be_a(Solargraph::Pin::Method)
@@ -790,8 +794,10 @@ class Foo
 
   it 'ignores malformed mixins' do
     closure = Solargraph::Pin::Namespace.new(name: 'Foo', closure: Solargraph::Pin::ROOT_PIN, type: :class)
-    mixin = Solargraph::Pin::Reference::Include.new(name: 'defined?(DidYouMean::SpellChecker) && defined?(DidYouMean::Correctable)', closure: closure)
-    api_map = Solargraph::ApiMap.new(pins: [closure, mixin])
+    mixin = Solargraph::Pin::Reference::Include.new(
+      name: 'defined?(DidYouMean::SpellChecker) && defined?(DidYouMean::Correctable)', closure: closure
+    )
+    api_map = described_class.new(pins: [closure, mixin])
     expect(api_map.get_method_stack('Foo', 'foo')).to be_empty
   end
 
@@ -812,9 +818,67 @@ def baz
       end
     ), 'test.rb')
 
-    api_map = Solargraph::ApiMap.new.map(source)
+    api_map = described_class.new.map(source)
 
     clip = api_map.clip_at('test.rb', [11, 10])
     expect(clip.infer.to_s).to eq('Symbol')
   end
+
+  it 'resolves aliases in identically named deeply nested classes' do
+    source = Solargraph::Source.load_string(%(
+      module A
+        module Bar
+          # @return [Integer]
+          def quux; 123; end
+        end
+
+        Baz = Bar
+
+        class Foo
+          include Baz
+        end
+      end
+
+      def c
+        b = A::Foo.new.quux
+        b
+      end
+    ), 'test.rb')
+
+    api_map = described_class.new.map(source)
+
+    clip = api_map.clip_at('test.rb', [16, 4])
+    expect(clip.infer.to_s).to eq('Integer')
+  end
+
+  it 'resolves aliases in nested classes' do
+    source = Solargraph::Source.load_string(%(
+      module A
+        module Bar
+          class Baz
+            # @return [Integer]
+            def quux; 123; end
+          end
+        end
+
+        Baz = Bar::Baz
+
+        class Foo
+          include Baz
+        end
+      end
+
+      def c
+        b = A::Foo.new.quux
+        b
+      end
+    ), 'test.rb')
+
+    api_map = described_class.new.map(source)
+
+    clip = api_map.clip_at('test.rb', [18, 4])
+    expect(clip.infer.to_s).to eq('Integer')
+  end
+
+  # rubocop:enable RSpec/InstanceVariable
 end
diff --git a/spec/complex_type/conforms_to_spec.rb b/spec/complex_type/conforms_to_spec.rb
new file mode 100644
index 000000000..f8a623bf0
--- /dev/null
+++ b/spec/complex_type/conforms_to_spec.rb
@@ -0,0 +1,257 @@
+# frozen_string_literal: true
+
+describe Solargraph::ComplexType do
+  let(:api_map) do
+    Solargraph::ApiMap.new
+  end
+
+  it 'validates simple core types' do
+    exp = described_class.parse('String')
+    inf = described_class.parse('String')
+    match = inf.conforms_to?(api_map, exp, :method_call)
+    expect(match).to be(true)
+  end
+
+  it 'invalidates simple core types' do
+    exp = described_class.parse('String')
+    inf = described_class.parse('Integer')
+    match = inf.conforms_to?(api_map, exp, :method_call)
+    expect(match).to be(false)
+  end
+
+  it 'allows subtype skew if told' do
+    exp = described_class.parse('Array<Integer>')
+    inf = described_class.parse('Array<String>')
+    match = inf.conforms_to?(api_map, exp, :method_call, [:allow_subtype_skew])
+    expect(match).to be(true)
+  end
+
+  it 'allows covariant behavior in parameters of Array' do
+    exp = described_class.parse('Array<Object>')
+    inf = described_class.parse('Array<Integer>')
+    match = inf.conforms_to?(api_map, exp, :method_call)
+    expect(match).to be(true)
+  end
+
+  it 'does not allow contravariant behavior in parameters of Array' do
+    exp = described_class.parse('Array<Integer>')
+    inf = described_class.parse('Array<Object>')
+    match = inf.conforms_to?(api_map, exp, :method_call)
+    expect(match).to be(false)
+  end
+
+  it 'allows covariant behavior in key types of Hash' do
+    exp = described_class.parse('Hash{Object => String}')
+    inf = described_class.parse('Hash{Integer => String}')
+    match = inf.conforms_to?(api_map, exp, :method_call)
+    expect(match).to be(true)
+  end
+
+  it 'accepts valid tuple conformance' do
+    exp = described_class.parse('Array(Integer, Integer)')
+    inf = described_class.parse('Array(Integer, Integer)')
+    match = inf.conforms_to?(api_map, exp, :method_call)
+    expect(match).to be(true)
+  end
+
+  it 'rejects invalid tuple conformance' do
+    exp = described_class.parse('Array(Integer, Integer)')
+    inf = described_class.parse('Array(Integer, String)')
+    match = inf.conforms_to?(api_map, exp, :method_call)
+    expect(match).to be(false)
+  end
+
+  it 'allows empty params when specified' do
+    exp = described_class.parse('Array(Integer, Integer)')
+    inf = described_class.parse('Array')
+    match = inf.conforms_to?(api_map, exp, :method_call, [:allow_empty_params])
+    expect(match).to be(true)
+  end
+
+  it 'validates expected superclasses' do
+    source = Solargraph::Source.load_string(%(
+      class Sup; end
+      class Sub < Sup; end
+    ))
+    api_map.map source
+    sup = described_class.parse('Sup')
+    sub = described_class.parse('Sub')
+    match = sub.conforms_to?(api_map, sup, :method_call)
+    expect(match).to be(true)
+  end
+
+  it 'handles singleton types compared against their literals' do
+    exp = Solargraph::ComplexType::UniqueType.new('nil', rooted: true)
+    inf = Solargraph::ComplexType::UniqueType.new('NilClass', rooted: true)
+    match = inf.conforms_to?(api_map, exp, :method_call)
+    expect(match).to be(true)
+  end
+
+  # it 'invalidates inferred superclasses (expected must be super)' do
+  # # @todo This test might be invalid. There are use cases where inheritance
+  # #   between inferred and expected classes should be acceptable in either
+  # #   direction.
+  # # source = Solargraph::Source.load_string(%(
+  # #   class Sup; end
+  # #   class Sub < Sup; end
+  # # ))
+  # # api_map.map source
+  # # sup = described_class.parse('Sup')
+  # # sub = described_class.parse('Sub')
+  # # match = Solargraph::TypeChecker::Checks.types_match?(api_map, sub, sup)
+  # # expect(match).to be(false)
+  # end
+
+  it 'fuzzy matches arrays with parameters' do
+    exp = described_class.parse('Array')
+    inf = described_class.parse('Array<String>')
+    match = inf.conforms_to?(api_map, exp, :method_call)
+    expect(match).to be(true)
+  end
+
+  it 'fuzzy matches sets with parameters' do
+    source = Solargraph::Source.load_string("require 'set'")
+    source_map = Solargraph::SourceMap.map(source)
+    api_map.catalog Solargraph::Bench.new(source_maps: [source_map], external_requires: ['set'])
+    exp = described_class.parse('Set')
+    inf = described_class.parse('Set<String>')
+    match = inf.conforms_to?(api_map, exp, :method_call)
+    expect(match).to be(true)
+  end
+
+  it 'fuzzy matches hashes with parameters' do
+    exp = described_class.parse('Hash{ Symbol => String}')
+    inf = described_class.parse('Hash')
+    match = inf.conforms_to?(api_map, exp, :method_call, [:allow_empty_params])
+    expect(match).to be(true)
+  end
+
+  it 'matches multiple types' do
+    exp = described_class.parse('String, Integer')
+    inf = described_class.parse('String, Integer')
+    match = inf.conforms_to?(api_map, exp, :method_call)
+    expect(match).to be(true)
+  end
+
+  it 'matches multiple types out of order' do
+    exp = described_class.parse('String, Integer')
+    inf = described_class.parse('Integer, String')
+    match = inf.conforms_to?(api_map, exp, :method_call)
+    expect(match).to be(true)
+  end
+
+  it 'invalidates inferred types missing from expected' do
+    exp = described_class.parse('String')
+    inf = described_class.parse('String, Integer')
+    match = inf.conforms_to?(api_map, exp, :method_call)
+    expect(match).to be(false)
+  end
+
+  it 'matches nil' do
+    exp = described_class.parse('nil')
+    inf = described_class.parse('nil')
+    match = inf.conforms_to?(api_map, exp, :method_call)
+    expect(match).to be(true)
+  end
+
+  it 'validates classes with expected superclasses' do
+    exp = described_class.parse('Class<Object>')
+    inf = described_class.parse('Class<String>')
+    match = inf.conforms_to?(api_map, exp, :method_call)
+    expect(match).to be(true)
+  end
+
+  it 'validates generic classes with expected Class' do
+    inf = described_class.parse('Class<String>')
+    exp = described_class.parse('Class')
+    match = inf.conforms_to?(api_map, exp, :method_call)
+    expect(match).to be(true)
+  end
+
+  context 'with invariant matching' do
+    it 'rejects String matching an Object' do
+      inf = described_class.parse('String')
+      exp = described_class.parse('Object')
+      match = inf.conforms_to?(api_map, exp, :method_call, variance: :invariant)
+      expect(match).to be(false)
+    end
+
+    it 'rejects Object matching an String' do
+      inf = described_class.parse('Object')
+      exp = described_class.parse('String')
+      match = inf.conforms_to?(api_map, exp, :method_call, variance: :invariant)
+      expect(match).to be(false)
+    end
+
+    it 'accepts String matching a String' do
+      inf = described_class.parse('String')
+      exp = described_class.parse('String')
+      match = inf.conforms_to?(api_map, exp, :method_call, variance: :invariant)
+      expect(match).to be(true)
+    end
+  end
+
+  context 'with contravariant matching' do
+    it 'rejects String matching an Objet' do
+      inf = described_class.parse('String')
+      exp = described_class.parse('Object')
+      match = inf.conforms_to?(api_map, exp, :method_call, variance: :contravariant)
+      expect(match).to be(false)
+    end
+
+    it 'accepts Object matching an String' do
+      inf = described_class.parse('Object')
+      exp = described_class.parse('String')
+      match = inf.conforms_to?(api_map, exp, :method_call, variance: :contravariant)
+      expect(match).to be(true)
+    end
+
+    it 'accepts String matching a String' do
+      inf = described_class.parse('String')
+      exp = described_class.parse('String')
+      match = inf.conforms_to?(api_map, exp, :method_call, variance: :contravariant)
+      expect(match).to be(true)
+    end
+  end
+
+  context 'with an inheritence relationship' do
+    let(:source) do
+      Solargraph::Source.load_string(%(
+        class Sup; end
+        class Sub < Sup; end
+      ))
+    end
+    let(:sup) { described_class.parse('Sup') }
+    let(:sub) { described_class.parse('Sub') }
+
+    before do
+      api_map.map source
+    end
+
+    it 'validates inheritance in one way' do
+      match = sub.conforms_to?(api_map, sup, :method_call, [:allow_reverse_match])
+      expect(match).to be(true)
+    end
+
+    it 'validates inheritance the other way' do
+      match = sup.conforms_to?(api_map, sub, :method_call, [:allow_reverse_match])
+      expect(match).to be(true)
+    end
+  end
+
+  context 'with inheritance relationship in allow_reverse_match mode' do
+    let(:api_map) { Solargraph::ApiMap.new }
+    let(:sup) { described_class.parse('String') }
+    let(:sub) { described_class.parse('Array') }
+
+    it 'conforms one way' do
+      match = sub.conforms_to?(api_map, sup, :method_call, [:allow_reverse_match])
+      expect(match).to be(false)
+    end
+
+    it 'conforms the other way' do
+      match = sup.conforms_to?(api_map, sub, :method_call, [:allow_reverse_match])
+      expect(match).to be(false)
+    end
+  end
+end
diff --git a/spec/complex_type/unique_type_spec.rb b/spec/complex_type/unique_type_spec.rb
new file mode 100644
index 000000000..2d9812600
--- /dev/null
+++ b/spec/complex_type/unique_type_spec.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+describe Solargraph::ComplexType::UniqueType do
+  describe '#any?' do
+    let(:type) { described_class.parse('String') }
+
+    it 'yields one and only one type, itself' do
+      types_encountered = []
+      type.any? { |t| types_encountered << t }
+      expect(types_encountered).to eq([type])
+    end
+  end
+end
diff --git a/spec/complex_type_spec.rb b/spec/complex_type_spec.rb
index f876d642f..dd20099eb 100644
--- a/spec/complex_type_spec.rb
+++ b/spec/complex_type_spec.rb
@@ -733,5 +733,33 @@ def make_bar
       expect(type.to_rbs).to eq('[Symbol, String, [Integer, Integer]]')
       expect(type.to_s).to eq('Array(Symbol, String, Array(Integer, Integer))')
     end
+
+    it 'recognizes String conforms with itself' do
+      api_map = Solargraph::ApiMap.new
+      ptype = Solargraph::ComplexType.parse('String')
+      atype = Solargraph::ComplexType.parse('String')
+      expect(atype.conforms_to?(api_map, ptype, :method_call)).to be(true)
+    end
+
+    it 'recognizes an erased container type conforms with itself' do
+      api_map = Solargraph::ApiMap.new
+      ptype = Solargraph::ComplexType.parse('Hash')
+      atype = Solargraph::ComplexType.parse('Hash')
+      expect(atype.conforms_to?(api_map, ptype, :method_call)).to be(true)
+    end
+
+    it 'recognizes an unerased container type conforms with itself' do
+      api_map = Solargraph::ApiMap.new
+      ptype = Solargraph::ComplexType.parse('Array<Integer>')
+      atype = Solargraph::ComplexType.parse('Array<Integer>')
+      expect(atype.conforms_to?(api_map, ptype, :method_call)).to be(true)
+    end
+
+    it 'recognizes a literal conforms with its type' do
+      api_map = Solargraph::ApiMap.new
+      ptype = Solargraph::ComplexType.parse('Symbol')
+      atype = Solargraph::ComplexType.parse(':foo')
+      expect(atype.conforms_to?(api_map, ptype, :method_call)).to be(true)
+    end
   end
 end
diff --git a/spec/convention/activesupport_concern_spec.rb b/spec/convention/activesupport_concern_spec.rb
index ffa12ee6c..e75e8749c 100644
--- a/spec/convention/activesupport_concern_spec.rb
+++ b/spec/convention/activesupport_concern_spec.rb
@@ -1,8 +1,11 @@
 # frozen_string_literal: true
 
 describe Solargraph::Convention::ActiveSupportConcern do
-  let :source do
-    Solargraph::Source.load_string(%(
+  let(:api_map) { Solargraph::ApiMap.new.map(source) }
+
+  context 'with a simple activesupport concern' do
+    let :source do
+      Solargraph::Source.load_string(%(
       # Example from here: https://api.rubyonrails.org/v7.0/classes/ActiveSupport/Concern.html
       require "active_support/concern"
 
@@ -30,12 +33,67 @@ class Host
 
       # this should print 'test'
     ), 'test.rb')
+    end
+
+    it 'handles block method super scenarios' do
+      api_map = Solargraph::ApiMap.new.map(source)
+
+      pin = api_map.get_method_stack('Host', 'method_injected_by_foo', scope: :class)
+      expect(pin.map(&:name)).to eq(['method_injected_by_foo'])
+    end
   end
 
-  it 'handles block method super scenarios' do
-    api_map = Solargraph::ApiMap.new.map(source)
+  context 'with static method defined in both included module and class' do
+    let :source do
+      Solargraph::Source.load_string(%(
+      # Example from here: https://api.rubyonrails.org/v7.0/classes/ActiveSupport/Concern.html
+      require "active_support/concern"
+
+      module Foo
+        extend ActiveSupport::Concern
+        included do
+          def self.my_method
+              puts 'test'
+          end
+        end
+      end
+
+      module Bar
+        extend ActiveSupport::Concern
+        include Foo
+
+        included do
+          self.my_method
+        end
+      end
+
+      class B
+        # @return [Numeric]
+        def self.my_method; end
+      end
+
+      class A < B
+        include Bar # It works, now Bar takes care of its dependencies
+
+        def self.my_method; end
+      end
+
+      # this should print 'test'
+    ), 'test.rb')
+    end
+
+    let(:pins) { api_map.get_method_stack('A', 'my_method', scope: :class) }
+
+    it 'sees all three methods' do
+      expect(pins.map(&:name)).to eq(%w[my_method my_method my_method])
+    end
+
+    it 'prefers directly defined method' do
+      expect(pins.map(&:path).first).to eq('A.my_method')
+    end
 
-    pin = api_map.get_method_stack('Host', 'method_injected_by_foo', scope: :class)
-    expect(pin.map(&:name)).to eq(['method_injected_by_foo'])
+    it 'is able to typify from superclass' do
+      expect(pins.first.typify(api_map).map(&:tag)).to include('Numeric')
+    end
   end
 end
diff --git a/spec/convention/gemfile_spec.rb b/spec/convention/gemfile_spec.rb
new file mode 100644
index 000000000..827da7993
--- /dev/null
+++ b/spec/convention/gemfile_spec.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+describe Solargraph::Convention::Gemfile do
+  describe 'parsing Gemfiles' do
+    def type_checker code
+      Solargraph::TypeChecker.load_string(code, 'Gemfile', :strong)
+    end
+
+    it 'typechecks valid files without error' do
+      checker = type_checker(%(
+        source 'https://rubygems.org'
+
+        ruby "~> 3.3.5"
+
+        gemspec name: 'solargraph'
+
+        # Local gemfile for development tools, etc.
+        local_gemfile = File.expand_path(".Gemfile", __dir__)
+        instance_eval File.read local_gemfile if File.exist? local_gemfile
+      ))
+
+      expect(checker.problems).to be_empty
+    end
+
+    it 'finds bad arguments to DSL methods' do
+      checker = type_checker(%(
+        source File
+
+        gemspec bad_name: 'solargraph'
+
+        # Local gemfile for development tools, etc.
+        local_gemfile = File.expand_path(".Gemfile", __dir__)
+        instance_eval File.read local_gemfile if File.exist? local_gemfile
+      ))
+
+      expect(checker.problems.map(&:message).sort)
+        .to eq(['Unrecognized keyword argument bad_name to Bundler::Dsl#gemspec',
+                'Wrong argument type for Bundler::Dsl#source: source expected String, received Class<File>'].sort)
+    end
+
+    it 'finds bad arguments to DSL ruby method' do
+      pending 'missing support for restargs in the typechecker'
+
+      checker = type_checker(%(
+        ruby 123
+      ))
+
+      expect(checker.problems.map(&:message))
+        .to eq(['Wrong argument type for Bundler::Dsl#ruby: ruby_version expected String, received Integer'])
+    end
+  end
+end
diff --git a/spec/convention/struct_definition_spec.rb b/spec/convention/struct_definition_spec.rb
index fe317a42b..0436dbe80 100644
--- a/spec/convention/struct_definition_spec.rb
+++ b/spec/convention/struct_definition_spec.rb
@@ -21,7 +21,7 @@
       expect(param_baz.return_type.tag).to eql('Integer')
     end
 
-    it 'should set closure to method on assignment operator parameters' do
+    it 'sets closure to method on assignment operator parameters' do
       source = Solargraph::SourceMap.load_string(%(
         # @param bar [String]
         # @param baz [Integer]
@@ -140,7 +140,7 @@ def type_checker code
       Solargraph::TypeChecker.load_string(code, 'test.rb', :strong)
     end
 
-    it 'should not crash' do
+    it 'does not crash' do
       checker = type_checker(%(
         Foo = Struct.new(:bar, :baz)
       ))
diff --git a/spec/doc_map_spec.rb b/spec/doc_map_spec.rb
index b03e573f0..cdf12d75a 100644
--- a/spec/doc_map_spec.rb
+++ b/spec/doc_map_spec.rb
@@ -1,80 +1,160 @@
 # frozen_string_literal: true
 
+require 'bundler'
+require 'benchmark'
+
 describe Solargraph::DocMap do
-  before :all do
-    # We use ast here because it's a known dependency.
-    gemspec = Gem::Specification.find_by_name('ast')
-    yard_pins = Solargraph::GemPins.build_yard_pins([], gemspec)
-    Solargraph::PinCache.serialize_yard_gem(gemspec, yard_pins)
+  subject(:doc_map) do
+    described_class.new(requires, workspace, out: out)
   end
 
-  it 'generates pins from gems' do
-    doc_map = Solargraph::DocMap.new(['ast'], [])
-    doc_map.cache_all!($stderr)
-    node_pin = doc_map.pins.find { |pin| pin.path == 'AST::Node' }
-    expect(node_pin).to be_a(Solargraph::Pin::Namespace)
+  let(:out) { StringIO.new }
+  let(:pre_cache) { true }
+  let(:requires) { [] }
+
+  let(:workspace) do
+    Solargraph::Workspace.new(Dir.pwd)
   end
 
-  it 'tracks unresolved requires' do
-    doc_map = Solargraph::DocMap.new(['not_a_gem'], [])
-    expect(doc_map.unresolved_requires).to include('not_a_gem')
+  let(:plain_doc_map) { described_class.new([], workspace, out: nil) }
+
+  before do
+    doc_map.cache_doc_map_gems!(nil) if pre_cache
   end
 
-  it 'tracks uncached_gemspecs' do
-    gemspec = Gem::Specification.new do |spec|
-      spec.name = 'not_a_gem'
-      spec.version = '1.0.0'
+  context 'with a require in solargraph test bundle' do
+    let(:requires) do
+      ['ast']
+    end
+
+    it 'generates pins from gems' do
+      node_pin = doc_map.pins.find { |pin| pin.path == 'AST::Node' }
+      expect(node_pin).to be_a(Solargraph::Pin::Namespace)
     end
-    allow(Gem::Specification).to receive(:find_by_path).and_return(gemspec)
-    doc_map = Solargraph::DocMap.new(['not_a_gem'], [gemspec])
-    expect(doc_map.uncached_yard_gemspecs).to eq([gemspec])
-    expect(doc_map.uncached_rbs_collection_gemspecs).to eq([gemspec])
   end
 
-  it 'imports all gems when bundler/require used' do
-    workspace = Solargraph::Workspace.new(Dir.pwd)
-    plain_doc_map = Solargraph::DocMap.new([], [], workspace)
-    doc_map_with_bundler_require = Solargraph::DocMap.new(['bundler/require'], [], workspace)
+  context 'with an invalid require' do
+    let(:requires) do
+      ['not_a_gem']
+    end
 
-    expect(doc_map_with_bundler_require.pins.length - plain_doc_map.pins.length).to be_positive
+    it 'tracks unresolved requires' do
+      # These are auto-required by solargraph-rspec in case the bundle
+      # includes these gems.  In our case, it doesn't!
+      unprovided_solargraph_rspec_requires = [
+        'rspec-rails',
+        'actionmailer',
+        'activerecord',
+        'shoulda-matchers',
+        'rspec-sidekiq',
+        'airborne',
+        'activesupport'
+      ]
+      expect(doc_map.unresolved_requires - unprovided_solargraph_rspec_requires)
+        .to eq(['not_a_gem'])
+    end
   end
 
-  it 'does not warn for redundant requires' do
-    # Requiring 'set' is unnecessary because it's already included in core. It
-    # might make sense to log redundant requires, but a warning is overkill.
-    expect(Solargraph.logger).not_to receive(:warn).with(/path set/)
-    Solargraph::DocMap.new(['set'], [])
+  context 'when deserialization takes a while' do
+    let(:pre_cache) { false }
+    let(:requires) { ['backport'] }
+
+    before do
+      # proxy this method to simulate a long-running deserialization
+      allow(Benchmark).to receive(:measure) do |&block|
+        block.call
+        5.0
+      end
+    end
+
+    it 'logs timing' do
+      # force lazy evaluation
+      _pins = doc_map.pins
+      expect(out.string).to include('Deserialized ').and include(' gem pins ').and include(' ms')
+    end
   end
 
-  it 'ignores nil requires' do
-    expect { Solargraph::DocMap.new([nil], []) }.not_to raise_error
+  context 'with an uncached but valid gemspec' do
+    let(:requires) { ['uncached_gem'] }
+    let(:pre_cache) { false }
+    let(:workspace) { instance_double(Solargraph::Workspace) }
+
+    it 'tracks uncached_gemspecs' do
+      pincache = instance_double(Solargraph::PinCache)
+      uncached_gemspec = Gem::Specification.new('uncached_gem', '1.0.0')
+      allow(workspace).to receive_messages(resolve_require: [], fresh_pincache: pincache)
+      allow(workspace).to receive(:global_environ).and_return(Solargraph::Environ.new)
+      allow(workspace).to receive(:resolve_require).with('uncached_gem').and_return([uncached_gemspec])
+      allow(workspace).to receive(:fetch_dependencies).with(uncached_gemspec, out: out).and_return([])
+      allow(pincache).to receive(:deserialize_combined_pin_cache).with(uncached_gemspec).and_return(nil)
+      expect(doc_map.uncached_gemspecs).to eq([uncached_gemspec])
+    end
   end
 
-  it 'ignores empty requires' do
-    expect { Solargraph::DocMap.new([''], []) }.not_to raise_error
+  context 'with require as bundle/require' do
+    it 'imports all gems when bundler/require used' do
+      doc_map_with_bundler_require = described_class.new(['bundler/require'], workspace, out: nil)
+      doc_map_with_bundler_require.cache_doc_map_gems!(nil)
+      expect(doc_map_with_bundler_require.pins.length - plain_doc_map.pins.length).to be_positive
+    end
   end
 
-  it 'collects dependencies' do
-    doc_map = Solargraph::DocMap.new(['rspec'], [])
-    expect(doc_map.dependencies.map(&:name)).to include('rspec-core')
+  context 'with a require not needed by Ruby core' do
+    let(:requires) { ['set'] }
+
+    it 'does not warn' do
+      # Requiring 'set' is unnecessary because it's already included in core. It
+      # might make sense to log redundant requires, but a warning is overkill.
+      allow(Solargraph.logger).to receive(:warn)
+      doc_map
+      expect(Solargraph.logger).not_to have_received(:warn).with(/path set/)
+    end
   end
 
-  it 'includes convention requires from environ' do
-    dummy_convention = Class.new(Solargraph::Convention::Base) do
-      def global(doc_map)
-        Solargraph::Environ.new(
-          requires: ['convention_gem1', 'convention_gem2']
-        )
-      end
+  context 'with a nil require' do
+    let(:requires) { [nil] }
+
+    it 'does not raise error' do
+      expect { doc_map }.not_to raise_error
     end
+  end
 
-    Solargraph::Convention.register dummy_convention
+  context 'with an empty require' do
+    let(:requires) { [''] }
 
-    doc_map = Solargraph::DocMap.new(['original_gem'], [])
+    it 'does not raise error' do
+      expect { doc_map }.not_to raise_error
+    end
+  end
 
-    expect(doc_map.requires).to include('original_gem', 'convention_gem1', 'convention_gem2')
+  context 'with a require that has dependencies' do
+    let(:requires) { ['rspec'] }
 
-    # Clean up the registered convention
-    Solargraph::Convention.deregister dummy_convention
+    it 'collects dependencies' do
+      expect(doc_map.dependencies.map(&:name)).to include('rspec-core')
+    end
+  end
+
+  context 'with convention' do
+    let(:pre_cache) { false }
+
+    it 'includes convention requires from environ' do
+      dummy_convention = Class.new(Solargraph::Convention::Base) do
+        def global(doc_map)
+          Solargraph::Environ.new(
+            requires: ['convention_gem1', 'convention_gem2']
+          )
+        end
+      end
+
+      Solargraph::Convention.register dummy_convention
+
+      doc_map = Solargraph::DocMap.new(['original_gem'], workspace)
+
+      expect(doc_map.requires).to include('original_gem', 'convention_gem1', 'convention_gem2')
+    ensure
+      # Clean up the registered convention
+      Solargraph::Convention.deregister dummy_convention
+    end
   end
 end
diff --git a/spec/gem_pins_spec.rb b/spec/gem_pins_spec.rb
index d630784cf..944afd331 100644
--- a/spec/gem_pins_spec.rb
+++ b/spec/gem_pins_spec.rb
@@ -1,14 +1,49 @@
 # frozen_string_literal: true
 
 describe Solargraph::GemPins do
-  it 'can merge YARD and RBS' do
-    gemspec = Gem::Specification.find_by_name('rbs')
-    yard_pins = Solargraph::GemPins.build_yard_pins([], gemspec)
-    rbs_map = Solargraph::RbsMap.from_gemspec(gemspec, nil, nil)
-    pins = Solargraph::GemPins.combine yard_pins, rbs_map.pins
-
-    core_root = pins.find { |pin| pin.path == 'RBS::EnvironmentLoader#core_root' }
-    expect(core_root.return_type.to_s).to eq('Pathname, nil')
-    expect(core_root.location.filename).to end_with('environment_loader.rb')
+  let(:workspace) { Solargraph::Workspace.new(Dir.pwd) }
+  let(:doc_map) { Solargraph::DocMap.new(requires, workspace, out: nil) }
+  let(:pin) { doc_map.pins.find { |pin| pin.path == path } }
+
+  before do
+    doc_map.cache_doc_map_gems!(STDERR) # rubocop:disable Style/GlobalStdStream
+  end
+
+  context 'with a combined method pin' do
+    let(:path) { 'RBS::EnvironmentLoader#core_root' }
+    let(:requires) { ['rbs'] }
+
+    it 'can merge YARD and RBS' do
+      expect(pin.source).to eq(:combined)
+    end
+
+    it 'finds types from RBS' do
+      expect(pin.return_type.to_s).to eq('Pathname, nil')
+    end
+
+    it 'finds locations from YARD' do
+      expect(pin.location.filename).to end_with('environment_loader.rb')
+    end
+  end
+
+  context 'with a YARD-only pin' do
+    let(:requires) { ['rake'] }
+    let(:path) { 'Rake::Task#prerequisites' }
+
+    it 'found a pin' do
+      expect(pin.source).not_to be_nil
+    end
+
+    it 'can merge YARD and RBS' do
+      expect(pin.source).to eq(:yardoc)
+    end
+
+    it 'does not find types from YARD in this case' do
+      expect(pin.return_type.to_s).to eq('undefined')
+    end
+
+    it 'finds locations from YARD' do
+      expect(pin.location.filename).to end_with('task.rb')
+    end
   end
 end
diff --git a/spec/language_server/host/diagnoser_spec.rb b/spec/language_server/host/diagnoser_spec.rb
index d59a843f1..69ee0b866 100644
--- a/spec/language_server/host/diagnoser_spec.rb
+++ b/spec/language_server/host/diagnoser_spec.rb
@@ -3,7 +3,8 @@
     host = double(Solargraph::LanguageServer::Host, options: { 'diagnostics' => true }, synchronizing?: false)
     diagnoser = Solargraph::LanguageServer::Host::Diagnoser.new(host)
     diagnoser.schedule 'file.rb'
-    expect(host).to receive(:diagnose).with('file.rb')
+    allow(host).to receive(:diagnose)
     diagnoser.tick
+    expect(host).to have_received(:diagnose).with('file.rb')
   end
 end
diff --git a/spec/language_server/host/message_worker_spec.rb b/spec/language_server/host/message_worker_spec.rb
index b9ce2a41f..9e5ce5721 100644
--- a/spec/language_server/host/message_worker_spec.rb
+++ b/spec/language_server/host/message_worker_spec.rb
@@ -2,11 +2,12 @@
   it "handle requests on queue" do
     host = double(Solargraph::LanguageServer::Host)
     message = {'method' => '$/example'}
-    expect(host).to receive(:receive).with(message).and_return(nil)
 
+    allow(host).to receive(:receive).with(message).and_return(nil)
     worker = Solargraph::LanguageServer::Host::MessageWorker.new(host)
     worker.queue(message)
     expect(worker.messages).to eq [message]
     worker.tick
+    expect(host).to have_received(:receive).with(message)
   end
 end
diff --git a/spec/language_server/host_spec.rb b/spec/language_server/host_spec.rb
index 40c8b7292..bccf00a87 100644
--- a/spec/language_server/host_spec.rb
+++ b/spec/language_server/host_spec.rb
@@ -247,7 +247,7 @@ def initialize(foo); end
       expect(symbols).not_to be_empty
     end
 
-    it "opens a file outside of prepared libraries" do
+    it "opens a file outside of prepared libraries", time_limit_seconds: 120 do
       @host.prepare(File.absolute_path(File.join('spec', 'fixtures', 'workspace')))
       @host.open('file:///file.rb', 'class Foo; end', 1)
       symbols = @host.document_symbols('file:///file.rb')
diff --git a/spec/language_server/message/text_document/definition_spec.rb b/spec/language_server/message/text_document/definition_spec.rb
index 72ff77f1e..b6c98b99b 100644
--- a/spec/language_server/message/text_document/definition_spec.rb
+++ b/spec/language_server/message/text_document/definition_spec.rb
@@ -1,4 +1,33 @@
 describe Solargraph::LanguageServer::Message::TextDocument::Definition do
+  it 'prepares empty directory' do
+    Dir.mktmpdir do |dir|
+      host = Solargraph::LanguageServer::Host.new
+      test_rb_path = File.join(dir, 'test.rb')
+      thing_rb_path = File.join(dir, 'thing.rb')
+      FileUtils.cp('spec/fixtures/workspace/lib/other.rb', test_rb_path)
+      FileUtils.cp('spec/fixtures/workspace/lib/thing.rb', thing_rb_path)
+      host.prepare(dir)
+      sleep 0.1 until host.libraries.all?(&:mapped?)
+      host.catalog
+      file_uri = Solargraph::LanguageServer::UriHelpers.file_to_uri(test_rb_path)
+      other_uri = Solargraph::LanguageServer::UriHelpers.file_to_uri(thing_rb_path)
+      message = Solargraph::LanguageServer::Message::TextDocument::Definition
+                .new(host, {
+                       'params' => {
+                         'textDocument' => {
+                           'uri' => file_uri
+                         },
+                         'position' => {
+                           'line' => 4,
+                           'character' => 10
+                         }
+                       }
+                     })
+      message.process
+      expect(message.result.first[:uri]).to eq(other_uri)
+    end
+  end
+
   it 'finds definitions of methods' do
     host = Solargraph::LanguageServer::Host.new
     host.prepare('spec/fixtures/workspace')
@@ -21,7 +50,7 @@
     expect(message.result.first[:uri]).to eq(other_uri)
   end
 
-  it 'finds definitions of require paths' do
+  it 'finds definitions of require paths', time_limit_seconds: 120 do
     path = File.absolute_path('spec/fixtures/workspace')
     host = Solargraph::LanguageServer::Host.new
     host.prepare(path)
diff --git a/spec/language_server/message/text_document/rename_spec.rb b/spec/language_server/message/text_document/rename_spec.rb
index 32fb6d011..d43793716 100644
--- a/spec/language_server/message/text_document/rename_spec.rb
+++ b/spec/language_server/message/text_document/rename_spec.rb
@@ -55,6 +55,9 @@ def foo(bar)
       }
     })
     rename.process
+    expect(rename.result).not_to be_nil
+    expect(rename.result[:changes]).not_to be_nil
+    expect(rename.result[:changes]['file:///file.rb']).not_to be_nil
     expect(rename.result[:changes]['file:///file.rb'].length).to eq(3)
   end
 
diff --git a/spec/language_server/protocol_spec.rb b/spec/language_server/protocol_spec.rb
index e88fb9c05..5021d3937 100644
--- a/spec/language_server/protocol_spec.rb
+++ b/spec/language_server/protocol_spec.rb
@@ -34,7 +34,7 @@ def stop
   end
 end
 
-describe Protocol do
+describe Protocol, order: :defined do
   before :all do
     @protocol = Protocol.new(Solargraph::LanguageServer::Host.new)
   end
@@ -82,7 +82,7 @@ def stop
   it "handles initialized" do
     @protocol.request 'initialized', nil
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
   end
 
   it "configured default dynamic registration capabilities from initialized" do
@@ -163,7 +163,7 @@ def bar baz
       }
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
     expect(response['result']['items'].length > 0).to be(true)
   end
 
@@ -173,6 +173,9 @@ def bar baz
     item = response['result']['items'].select{|h| h['label'] == 'bar'}.first
     @protocol.request 'completionItem/resolve', item
     response = @protocol.response
+    expect(response).not_to be_nil
+    expect(response['error']).to be_nil
+    expect(response['result']).to be_a(Hash)
     expect(response['result']['documentation']['value']).to include('bar method')
   end
 
@@ -186,7 +189,7 @@ def bar baz
         'character' => 1
       }
     }
-    expect(@protocol.response['error']).to be_nil
+    expect(@protocol.response['error']).to be_nil, ->{ "Received response #{@protocol.response.inspect} wtih unexpected error" }
   end
 
   it "documents YARD pins" do
@@ -212,7 +215,7 @@ def bar baz
       'query' => 'test'
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
   end
 
   it "handles textDocument/definition" do
@@ -227,7 +230,7 @@ def bar baz
       }
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
     expect(response['result']).not_to be_empty
   end
 
@@ -242,7 +245,7 @@ def bar baz
       }
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
     expect(response['result']).to be_empty
   end
 
@@ -253,7 +256,7 @@ def bar baz
       }
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
   end
 
   it "handles textDocument/hover" do
@@ -267,7 +270,7 @@ def bar baz
       }
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
     # Given this request hovers over `Foo`, the result should not be empty
     expect(response['result']['contents']).not_to be_empty
   end
@@ -282,7 +285,7 @@ def bar baz
         'character' => 17
       }
     }
-    expect(@protocol.response['error']).to be_nil
+    expect(@protocol.response['error']).to be_nil, ->{ "Received response #{@protocol.response.inspect} wtih unexpected error" }
   end
 
   it "handles textDocument/signatureHelp" do
@@ -296,7 +299,7 @@ def bar baz
       }
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
     expect(response['result']['signatures']).not_to be_empty
   end
 
@@ -305,7 +308,7 @@ def bar baz
       'query' => 'Foo'
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
     expect(response['result']).not_to be_empty
   end
 
@@ -320,7 +323,7 @@ def bar baz
       }
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
     expect(response['result']).not_to be_empty
   end
 
@@ -335,7 +338,7 @@ def bar baz
       }
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
     expect(response['result']).not_to be_empty
   end
 
@@ -351,7 +354,7 @@ def bar baz
       'newName' => 'new_name'
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
     expect(response['result']['changes']['file:///file.rb']).to be_a(Array)
   end
 
@@ -367,7 +370,7 @@ def bar baz
       'newName' => 'new_name'
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
     expect(response['result']).to be_a(Hash)
   end
 
@@ -378,7 +381,7 @@ def bar baz
       }
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
     expect(response['result'].length).not_to be_zero
   end
 
@@ -397,7 +400,7 @@ def bar baz
       'query' => 'Foo#bar'
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
     expect(response['result']['content']).not_to be_empty
   end
 
@@ -406,7 +409,7 @@ def bar baz
       'query' => 'String'
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
     expect(response['result']['content']).not_to be_empty
   end
 
@@ -426,7 +429,7 @@ def bar baz
   it "handles $/solargraph/checkGemVersion" do
     @protocol.request '$/solargraph/checkGemVersion', { verbose: false }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
     expect(response['result']['installed']).to be_a(String)
     expect(response['result']['available']).to be_a(String)
   end
@@ -434,7 +437,7 @@ def bar baz
   it "handles $/solargraph/documentGems" do
     @protocol.request '$/solargraph/documentGems', {}
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
   end
 
   it "handles textDocument/formatting" do
@@ -451,7 +454,7 @@ def bar baz
       }
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
     expect(response['result'].first['newText']).to be_a(String)
   end
 
@@ -469,7 +472,7 @@ def bar baz
       }
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
     # @todo Rules for parenthesized parameters have apparently changed in RuboCop 0.89
     # expect(response['result'].first['newText']).to include('def barbaz(parameter); end')
   end
@@ -490,7 +493,7 @@ def bar baz
       ]
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
   end
 
   it "handles didChangeWatchedFiles for changed files" do
@@ -503,7 +506,7 @@ def bar baz
       ]
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
   end
 
   it "handles didChangeWatchedFiles for deleted files" do
@@ -516,7 +519,7 @@ def bar baz
       ]
     }
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
   end
 
   it "handles didChangeWatchedFiles for invalid change types" do
@@ -529,7 +532,7 @@ def bar baz
       ]
     }
     response = @protocol.response
-    expect(response['error']).not_to be_nil
+    expect(response['error']).not_to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
   end
 
   it "adds folders to the workspace" do
@@ -583,13 +586,13 @@ def bar baz
   it "handles shutdown" do
     @protocol.request 'shutdown', {}
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
   end
 
   it "handles exit" do
     @protocol.request 'exit', {}
     response = @protocol.response
-    expect(response['error']).to be_nil
+    expect(response['error']).to be_nil, ->{ "Received response #{response.inspect} wtih unexpected error" }
     expect(@protocol.host.stopped?).to be(true)
   end
 end
diff --git a/spec/library_spec.rb b/spec/library_spec.rb
index bea0f2983..f7daafdf4 100644
--- a/spec/library_spec.rb
+++ b/spec/library_spec.rb
@@ -26,6 +26,32 @@
     expect(completion.pins.map(&:name)).to include('x')
   end
 
+  context 'with a require from a not-yet-cached external gem' do
+    before do
+      Solargraph::Shell.new.uncache('backport')
+    end
+
+    it "returns a Completion", time_limit_seconds: 50 do
+      library = Solargraph::Library.new(Solargraph::Workspace.new(Dir.pwd,
+                                                                  Solargraph::Workspace::Config.new))
+      library.attach Solargraph::Source.load_string(%(
+        require 'backport'
+
+        # @param adapter [Backport::Adapter]
+        def foo(adapter)
+          adapter.remo
+        end
+      ), 'file.rb', 0)
+      completion = nil
+      # give Solargraph time to cache the gem
+      while (completion = library.completions_at('file.rb', 5, 19)).pins.empty?
+        sleep 0.25
+      end
+      expect(completion).to be_a(Solargraph::SourceMap::Completion)
+      expect(completion.pins.map(&:name)).to include('remote')
+    end
+  end
+
   context 'with a require from an already-cached external gem' do
     before do
       Solargraph::Shell.new.gems('backport')
@@ -132,6 +158,20 @@ def bar baz, key: ''
     # @todo More tests
   end
 
+  it 'diagnoses using all reporters' do
+    directory = ''
+    config = instance_double(Solargraph::Workspace::Config)
+    allow(config).to receive_messages(plugins: [], required: [], reporters: ['all!'])
+    workspace = Solargraph::Workspace.new directory, config
+    library = Solargraph::Library.new workspace
+    src = Solargraph::Source.load_string(%(
+      puts 'hello'
+    ), 'file.rb', 0)
+    library.attach src
+    result = library.diagnose 'file.rb'
+    expect(result.to_s).to include('rubocop')
+  end
+
   it "documents symbols" do
     library = Solargraph::Library.new
     src = Solargraph::Source.load_string(%(
@@ -147,10 +187,47 @@ def bar
     expect(pins.map(&:path)).to include('Foo#bar')
   end
 
-  it "collects references to an instance method symbol" do
-    workspace = Solargraph::Workspace.new('*')
-    library = Solargraph::Library.new(workspace)
-    src1 = Solargraph::Source.load_string(%(
+  describe '#references_from' do
+    it "collects references to a new method on a constant from assignment of Class.new" do
+      workspace = Solargraph::Workspace.new('*')
+      library = Solargraph::Library.new(workspace)
+      src1 = Solargraph::Source.load_string(%(
+        Foo.new
+      ), 'file1.rb', 0)
+      library.merge src1
+      src2 = Solargraph::Source.load_string(%(
+        Foo = Class.new
+      ), 'file2.rb', 0)
+      library.merge src2
+      library.catalog
+      locs = library.references_from('file1.rb', 1, 12)
+      expect(locs.map { |l| [l.filename, l.range.start.line] })
+        .to eq([["file1.rb", 1]])
+    end
+
+    it "collects references to a new method to a constant from assignment" do
+      workspace = Solargraph::Workspace.new('*')
+      library = Solargraph::Library.new(workspace)
+      src1 = Solargraph::Source.load_string(%(
+        Foo.new
+      ), 'file1.rb', 0)
+      library.merge src1
+      src2 = Solargraph::Source.load_string(%(
+        class Foo
+        end
+        blah = Foo.new
+      ), 'file2.rb', 0)
+      library.merge src2
+      library.catalog
+      locs = library.references_from('file2.rb', 3, 21)
+      expect(locs.map { |l| [l.filename, l.range.start.line] })
+        .to eq([["file1.rb", 1], ["file2.rb", 3]])
+    end
+
+    it "collects references to an instance method symbol" do
+      workspace = Solargraph::Workspace.new('*')
+      library = Solargraph::Library.new(workspace)
+      src1 = Solargraph::Source.load_string(%(
       class Foo
         def bar
         end
@@ -158,8 +235,8 @@ def bar
 
       Foo.new.bar
     ), 'file1.rb', 0)
-    library.merge src1
-    src2 = Solargraph::Source.load_string(%(
+      library.merge src1
+      src2 = Solargraph::Source.load_string(%(
       foo = Foo.new
       foo.bar
       class Other
@@ -167,17 +244,17 @@ def bar; end
       end
       Other.new.bar
     ), 'file2.rb', 0)
-    library.merge src2
-    library.catalog
-    locs = library.references_from('file2.rb', 2, 11)
-    expect(locs.length).to eq(3)
-    expect(locs.select{|l| l.filename == 'file2.rb' && l.range.start.line == 6}).to be_empty
-  end
+      library.merge src2
+      library.catalog
+      locs = library.references_from('file2.rb', 2, 11)
+      expect(locs.length).to eq(3)
+      expect(locs.select{|l| l.filename == 'file2.rb' && l.range.start.line == 6}).to be_empty
+    end
 
-  it "collects references to a class method symbol" do
-    workspace = Solargraph::Workspace.new('*')
-    library = Solargraph::Library.new(workspace)
-    src1 = Solargraph::Source.load_string(%(
+    it "collects references to a class method symbol" do
+      workspace = Solargraph::Workspace.new('*')
+      library = Solargraph::Library.new(workspace)
+      src1 = Solargraph::Source.load_string(%(
       class Foo
         def self.bar
         end
@@ -189,8 +266,8 @@ def bar
       Foo.bar
       Foo.new.bar
     ), 'file1.rb', 0)
-    library.merge src1
-    src2 = Solargraph::Source.load_string(%(
+      library.merge src1
+      src2 = Solargraph::Source.load_string(%(
       Foo.bar
       Foo.new.bar
       class Other
@@ -200,48 +277,48 @@ def bar; end
       Other.bar
       Other.new.bar
     ), 'file2.rb', 0)
-    library.merge src2
-    library.catalog
-    locs = library.references_from('file2.rb', 1, 11)
-    expect(locs.length).to eq(3)
-    expect(locs.select{|l| l.filename == 'file1.rb' && l.range.start.line == 2}).not_to be_empty
-    expect(locs.select{|l| l.filename == 'file1.rb' && l.range.start.line == 9}).not_to be_empty
-    expect(locs.select{|l| l.filename == 'file2.rb' && l.range.start.line == 1}).not_to be_empty
-  end
+      library.merge src2
+      library.catalog
+      locs = library.references_from('file2.rb', 1, 11)
+      expect(locs.length).to eq(3)
+      expect(locs.select{|l| l.filename == 'file1.rb' && l.range.start.line == 2}).not_to be_empty
+      expect(locs.select{|l| l.filename == 'file1.rb' && l.range.start.line == 9}).not_to be_empty
+      expect(locs.select{|l| l.filename == 'file2.rb' && l.range.start.line == 1}).not_to be_empty
+    end
 
-  it "collects stripped references to constant symbols" do
-    workspace = Solargraph::Workspace.new('*')
-    library = Solargraph::Library.new(workspace)
-    src1 = Solargraph::Source.load_string(%(
+    it "collects stripped references to constant symbols" do
+      workspace = Solargraph::Workspace.new('*')
+      library = Solargraph::Library.new(workspace)
+      src1 = Solargraph::Source.load_string(%(
       class Foo
         def bar
         end
       end
       Foo.new.bar
     ), 'file1.rb', 0)
-    library.merge src1
-    src2 = Solargraph::Source.load_string(%(
+      library.merge src1
+      src2 = Solargraph::Source.load_string(%(
       class Other
         foo = Foo.new
         foo.bar
       end
     ), 'file2.rb', 0)
-    library.merge src2
-    library.catalog
-    locs = library.references_from('file1.rb', 1, 12, strip: true)
-    expect(locs.length).to eq(3)
-    locs.each do |l|
-      code = library.read_text(l.filename)
-      o1 = Solargraph::Position.to_offset(code, l.range.start)
-      o2 = Solargraph::Position.to_offset(code, l.range.ending)
-      expect(code[o1..o2-1]).to eq('Foo')
+      library.merge src2
+      library.catalog
+      locs = library.references_from('file1.rb', 1, 12, strip: true)
+      expect(locs.length).to eq(3)
+      locs.each do |l|
+        code = library.read_text(l.filename)
+        o1 = Solargraph::Position.to_offset(code, l.range.start)
+        o2 = Solargraph::Position.to_offset(code, l.range.ending)
+        expect(code[o1..o2-1]).to eq('Foo')
+      end
     end
-  end
 
-  it 'rejects new references from different classes' do
-    workspace = Solargraph::Workspace.new('*')
-    library = Solargraph::Library.new(workspace)
-    source = Solargraph::Source.load_string(%(
+    it 'rejects new references from different classes' do
+      workspace = Solargraph::Workspace.new('*')
+      library = Solargraph::Library.new(workspace)
+      source = Solargraph::Source.load_string(%(
       class Foo
         def bar
         end
@@ -249,106 +326,131 @@ def bar
       Foo.new
       Array.new
     ), 'test.rb')
-    library.merge source
-    library.catalog
-    foo_new_locs = library.references_from('test.rb', 5, 10)
-    expect(foo_new_locs).to eq([Solargraph::Location.new('test.rb', Solargraph::Range.from_to(5, 10, 5, 13))])
-    obj_new_locs = library.references_from('test.rb', 6, 12)
-    expect(obj_new_locs).to eq([Solargraph::Location.new('test.rb', Solargraph::Range.from_to(6, 12, 6, 15))])
-  end
+      library.merge source
+      library.catalog
+      foo_new_locs = library.references_from('test.rb', 5, 10)
+      expect(foo_new_locs).to eq([Solargraph::Location.new('test.rb', Solargraph::Range.from_to(5, 10, 5, 13))])
+      obj_new_locs = library.references_from('test.rb', 6, 12)
+      expect(obj_new_locs).to eq([Solargraph::Location.new('test.rb', Solargraph::Range.from_to(6, 12, 6, 15))])
+    end
 
-  it "searches the core for queries" do
-    library = Solargraph::Library.new
-    result = library.search('String')
-    expect(result).not_to be_empty
-  end
+    it "searches the core for queries" do
+      library = Solargraph::Library.new
+      result = library.search('String')
+      expect(result).not_to be_empty
+    end
 
-  it "returns YARD documentation from the core" do
-    library = Solargraph::Library.new
-    api_map, result = library.document('String')
-    expect(result).not_to be_empty
-    expect(result.first).to be_a(Solargraph::Pin::Base)
-  end
+    it "returns YARD documentation from the core" do
+      library = Solargraph::Library.new
+      api_map, result = library.document('String')
+      expect(result).not_to be_empty
+      expect(result.first).to be_a(Solargraph::Pin::Base)
+    end
 
-  it "returns YARD documentation from sources" do
-    library = Solargraph::Library.new
-    src = Solargraph::Source.load_string(%(
+    it "returns YARD documentation from sources" do
+      library = Solargraph::Library.new
+      src = Solargraph::Source.load_string(%(
       class Foo
         # My bar method
         def bar; end
       end
     ), 'test.rb', 0)
-    library.attach src
-    api_map, result = library.document('Foo#bar')
-    expect(result).not_to be_empty
-    expect(result.first).to be_a(Solargraph::Pin::Base)
-  end
+      library.attach src
+      api_map, result = library.document('Foo#bar')
+      expect(result).not_to be_empty
+      expect(result.first).to be_a(Solargraph::Pin::Base)
+    end
 
-  it "synchronizes sources from updaters" do
-    library = Solargraph::Library.new
-    src = Solargraph::Source.load_string(%(
+    it "synchronizes sources from updaters" do
+      library = Solargraph::Library.new
+      src = Solargraph::Source.load_string(%(
       class Foo
       end
     ), 'test.rb', 1)
-    library.attach src
-    repl = %(
+      library.attach src
+      repl = %(
       class Foo
         def bar; end
       end
     )
-    updater = Solargraph::Source::Updater.new(
-      'test.rb',
-      2,
-      [Solargraph::Source::Change.new(nil, repl)]
-    )
-    library.attach src.synchronize(updater)
-    expect(library.current.code).to eq(repl)
-  end
+      updater = Solargraph::Source::Updater.new(
+        'test.rb',
+        2,
+        [Solargraph::Source::Change.new(nil, repl)]
+      )
+      library.attach src.synchronize(updater)
+      expect(library.current.code).to eq(repl)
+    end
 
-  it "finds unique references" do
-    library = Solargraph::Library.new(Solargraph::Workspace.new('*'))
-    src1 = Solargraph::Source.load_string(%(
+    it "finds unique references" do
+      library = Solargraph::Library.new(Solargraph::Workspace.new('*'))
+      src1 = Solargraph::Source.load_string(%(
       class Foo
       end
     ), 'src1.rb', 1)
-    library.merge src1
-    src2 = Solargraph::Source.load_string(%(
+      library.merge src1
+      src2 = Solargraph::Source.load_string(%(
       foo = Foo.new
     ), 'src2.rb', 1)
-    library.merge src2
-    library.catalog
-    refs = library.references_from('src2.rb', 1, 12)
-    expect(refs.length).to eq(2)
-  end
+      library.merge src2
+      library.catalog
+      refs = library.references_from('src2.rb', 1, 12)
+      expect(refs.length).to eq(2)
+    end
 
-  it "includes method parameters in references" do
-    library = Solargraph::Library.new(Solargraph::Workspace.new('*'))
-    source = Solargraph::Source.load_string(%(
+    it "includes method parameters in references" do
+      library = Solargraph::Library.new(Solargraph::Workspace.new('*'))
+      source = Solargraph::Source.load_string(%(
       class Foo
         def bar(baz)
           baz.upcase
         end
       end
     ), 'test.rb', 1)
-    library.attach source
-    from_def = library.references_from('test.rb', 2, 16)
-    expect(from_def.length).to eq(2)
-    from_ref = library.references_from('test.rb', 3, 10)
-    expect(from_ref.length).to eq(2)
-  end
+      library.attach source
+      from_def = library.references_from('test.rb', 2, 16)
+      expect(from_def.length).to eq(2)
+      from_ref = library.references_from('test.rb', 3, 10)
+      expect(from_ref.length).to eq(2)
+    end
 
-  it "includes block parameters in references" do
-    library = Solargraph::Library.new(Solargraph::Workspace.new('*'))
-    source = Solargraph::Source.load_string(%(
+    it "lies about names when client can't handle the truth" do
+      library = Solargraph::Library.new(Solargraph::Workspace.new('*'))
+      source = Solargraph::Source.load_string(%(
+      class Foo
+        def 🤦🏻foo♀️; 123; end
+      end
+    ), 'test.rb', 1)
+      library.attach source
+      from_def = library.references_from('test.rb', 2, 16, strip: true)
+      expect(from_def.first.range.start.column).to eq(14)
+    end
+
+    it "tells the truth about names when client can handle the truth" do
+      library = Solargraph::Library.new(Solargraph::Workspace.new('*'))
+      source = Solargraph::Source.load_string(%(
+      class Foo
+        def 🤦🏻foo♀️; 123; end
+      end
+    ), 'test.rb', 1)
+      library.attach source
+      from_def = library.references_from('test.rb', 2, 16, strip: false)
+      expect(from_def.first.range.start.column).to eq(12)
+    end
+
+    it "includes block parameters in references" do
+      library = Solargraph::Library.new(Solargraph::Workspace.new('*'))
+      source = Solargraph::Source.load_string(%(
       100.times do |foo|
         puts foo
       end
     ), 'test.rb', 1)
-    library.attach source
-    from_def = library.references_from('test.rb', 1, 20)
-    expect(from_def.length).to eq(2)
-    from_ref = library.references_from('test.rb', 2, 13)
-    expect(from_ref.length).to eq(2)
+      library.attach source
+      from_def = library.references_from('test.rb', 1, 20)
+      expect(from_def.length).to eq(2)
+      from_ref = library.references_from('test.rb', 2, 13)
+      expect(from_ref.length).to eq(2)
+    end
   end
 
   it 'defines YARD tags' do
diff --git a/spec/parser/node_methods_spec.rb b/spec/parser/node_methods_spec.rb
index eb026725b..f9504b584 100644
--- a/spec/parser/node_methods_spec.rb
+++ b/spec/parser/node_methods_spec.rb
@@ -440,5 +440,45 @@ def super_with_block
       calls = Solargraph::Parser::NodeMethods.call_nodes_from(source.node)
       expect(calls).to be_one
     end
+
+    it 'handles chained calls' do
+      source = Solargraph::Source.load_string(%(
+        Foo.new.bar('string')
+      ))
+      calls = Solargraph::Parser::NodeMethods.call_nodes_from(source.node)
+      expect(calls.length).to eq(2)
+    end
+
+    it 'handles calls from inside array literals' do
+      source = Solargraph::Source.load_string(%(
+        [ Foo.new.bar('string') ]
+      ))
+      calls = Solargraph::Parser::NodeMethods.call_nodes_from(source.node)
+      expect(calls.length).to eq(2)
+    end
+
+    it 'handles calls from inside array literals that are chained' do
+      source = Solargraph::Source.load_string(%(
+        [ Foo.new.bar('string') ].compact
+      ))
+      calls = Solargraph::Parser::NodeMethods.call_nodes_from(source.node)
+      expect(calls.length).to eq(3)
+    end
+
+    it 'does not over-report calls' do
+      source = Solargraph::Source.load_string(%(
+        class Foo
+          def something
+          end
+        end
+        class Bar < Foo
+          def something
+            super(1) + 2
+          end
+        end
+      ))
+      calls = Solargraph::Parser::NodeMethods.call_nodes_from(source.node)
+      expect(calls.length).to eq(2)
+    end
   end
 end
diff --git a/spec/pin/combine_with_spec.rb b/spec/pin/combine_with_spec.rb
new file mode 100644
index 000000000..cc80d76d5
--- /dev/null
+++ b/spec/pin/combine_with_spec.rb
@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+describe Solargraph::Pin::Base, '#combine_with' do
+  it 'combines return types with another method pin with same arity' do
+    pin1 = Solargraph::Pin::Method.new(name: 'foo', parameters: [], comments: '@return [String]')
+    pin2 = Solargraph::Pin::Method.new(name: 'foo', parameters: [], comments: '@return [Integer]')
+    combined = pin1.combine_with(pin2)
+    expect(combined.return_type.to_s).to eq('String, Integer')
+  end
+
+  it 'combines return types with another method without type parameters' do
+    pin1 = Solargraph::Pin::Method.new(name: 'foo', parameters: [], comments: '@return [Array<String>]')
+    pin2 = Solargraph::Pin::Method.new(name: 'foo', parameters: [], comments: '@return [Array]')
+    combined = pin1.combine_with(pin2)
+    expect(combined.return_type.to_s).to eq('Array<String>')
+  end
+
+  context 'with dodgy return types' do
+    let(:dodgy_location_pin) do
+      range = Solargraph::Range.new(Solargraph::Position.new(1, 0), Solargraph::Position.new(1, 10))
+      location = Solargraph::Location.new('/home/user/.rbenv/versions/3.1.7/lib/ruby/gems/3.1.0/gems' \
+                                          '/activesupport-7.0.8.7/lib/active_support/core_ext/object' \
+                                          '/conversions.rb',
+                                          range)
+      Solargraph::Pin::Method.new(name: 'foo', parameters: [], comments: '@return [Object]',
+                                  location: location)
+    end
+
+    let(:normal_pin) { Solargraph::Pin::Method.new(name: 'foo', parameters: [], comments: '@return [self]') }
+
+    it 'combines a dodgy return type with a valid one' do
+      combined = dodgy_location_pin.combine_with(normal_pin)
+      expect(combined.return_type.to_s).to eq('self')
+    end
+
+    it 'combines a valid return type with a dodgy one' do
+      combined = normal_pin.combine_with(dodgy_location_pin)
+      expect(combined.return_type.to_s).to eq('self')
+    end
+  end
+
+  context 'with return types that should probably be self' do
+    let(:closure) do
+      Solargraph::Pin::Namespace.new(
+        name: 'Foo',
+        closure: Solargraph::Pin::ROOT_PIN,
+        type: :class
+      )
+    end
+
+    let(:likely_selfy_pin) do
+      Solargraph::Pin::Method.new(name: 'foo', closure: closure, parameters: [], comments: '@return [::Foo]')
+    end
+
+    let(:selfy_pin) { Solargraph::Pin::Method.new(name: 'foo', closure: closure, parameters: [], comments: '@return [self]') }
+
+    it 'combines a selfy return type with a likely-selfy one' do
+      combined = likely_selfy_pin.combine_with(selfy_pin)
+      expect(combined.return_type.to_s).to eq('self')
+    end
+
+    it 'combines a likely-selfy return type with a selfy one' do
+      combined = selfy_pin.combine_with(likely_selfy_pin)
+      expect(combined.return_type.to_s).to eq('self')
+    end
+  end
+end
diff --git a/spec/pin/local_variable_spec.rb b/spec/pin/local_variable_spec.rb
index 88075efb9..369a58bc4 100644
--- a/spec/pin/local_variable_spec.rb
+++ b/spec/pin/local_variable_spec.rb
@@ -46,7 +46,7 @@ class Bar
     # set env variable 'FOO' to 'true' in block
 
     with_env_var('SOLARGRAPH_ASSERTS', 'on') do
-      expect(Solargraph.asserts_on?(:combine_with_closure_name)).to be true
+      expect(Solargraph.asserts_on?).to be true
       expect { pin1.combine_with(pin2) }.to raise_error(RuntimeError, /Inconsistent :closure name/)
     end
   end
diff --git a/spec/pin/symbol_spec.rb b/spec/pin/symbol_spec.rb
index 98d88137e..16961cadc 100644
--- a/spec/pin/symbol_spec.rb
+++ b/spec/pin/symbol_spec.rb
@@ -1,10 +1,15 @@
 describe Solargraph::Pin::Symbol do
   context "as an unquoted literal" do
-    it "is a kind of keyword" do
+    it "is a kind of keyword to the LSP" do
       pin = Solargraph::Pin::Symbol.new(nil, ':symbol')
       expect(pin.completion_item_kind).to eq(Solargraph::LanguageServer::CompletionItemKinds::KEYWORD)
     end
 
+    it "has global closure" do
+      pin = Solargraph::Pin::Symbol.new(nil, ':symbol')
+      expect(pin.closure).to eq(Solargraph::Pin::ROOT_PIN)
+    end
+
     it "has a Symbol return type" do
       pin = Solargraph::Pin::Symbol.new(nil, ':symbol')
       expect(pin.return_type.tag).to eq('Symbol')
diff --git a/spec/pin_cache_spec.rb b/spec/pin_cache_spec.rb
new file mode 100644
index 000000000..0a11686f5
--- /dev/null
+++ b/spec/pin_cache_spec.rb
@@ -0,0 +1,197 @@
+# frozen_string_literal: true
+
+require 'bundler'
+require 'benchmark'
+
+describe Solargraph::PinCache do
+  subject(:pin_cache) do
+    described_class.new(rbs_collection_path: '.gem_rbs_collection',
+                        rbs_collection_config_path: 'rbs_collection.yaml',
+                        directory: Dir.pwd,
+                        yard_plugins: ['activesupport-concern'])
+  end
+
+  describe '#cached?' do
+    it 'returns true for a gem that is cached' do
+      allow(File).to receive(:file?).with(%r{.*stdlib/backport.ser$}).and_return(false)
+      allow(File).to receive(:file?).with(%r{.*combined/.*/backport-.*.ser$}).and_return(true)
+
+      gemspec = Gem::Specification.find_by_name('backport')
+      expect(pin_cache.cached?(gemspec)).to be true
+    end
+
+    it 'returns false for a gem that is not cached' do
+      gemspec = Gem::Specification.new.tap do |spec|
+        spec.name = 'nonexistent'
+        spec.version = '0.0.1'
+      end
+      expect(pin_cache.cached?(gemspec)).to be false
+    end
+  end
+
+  describe '.core?' do
+    it 'returns true when core pins exist' do
+      allow(File).to receive(:file?).with(%r{.*/core.ser$}).and_return(true)
+
+      expect(described_class.core?).to be true
+    end
+
+    it "returns true when core pins don't" do
+      allow(File).to receive(:file?).with(%r{.*/core.ser$}).and_return(false)
+
+      expect(described_class.core?).to be false
+    end
+  end
+
+  describe '#possible_stdlibs' do
+    it 'is tolerant of less usual Ruby installations' do
+      stub_const('Gem::RUBYGEMS_DIR', nil)
+
+      expect(pin_cache.possible_stdlibs).to eq([])
+    end
+  end
+
+  describe '#cache_all_stdlibs' do
+    it 'creates stdlibmaps' do
+      allow(Solargraph::RbsMap::StdlibMap).to receive(:new).and_return(instance_double(Solargraph::RbsMap::StdlibMap))
+
+      pin_cache.cache_all_stdlibs
+
+      expect(Solargraph::RbsMap::StdlibMap).to have_received(:new).at_least(:once)
+    end
+  end
+
+  describe '#cache_gem' do
+    context 'with an already in-memory gem' do
+      let(:backport_gemspec) { Gem::Specification.find_by_name('backport') }
+
+      before do
+        pin_cache.cache_gem(gemspec: backport_gemspec, out: nil)
+      end
+
+      it 'does not load the gem again' do
+        allow(Marshal).to receive(:load).and_call_original
+
+        pin_cache.cache_gem(gemspec: backport_gemspec, out: nil)
+
+        expect(Marshal).not_to have_received(:load).with(anything)
+      end
+    end
+
+    context 'with the parser gem' do
+      before do
+        Solargraph::Shell.new.uncache('parser')
+        allow(Solargraph::Yardoc).to receive(:build_docs)
+      end
+
+      it 'chooses not to use YARD' do
+        parser_gemspec = Gem::Specification.find_by_name('parser')
+        pin_cache.cache_gem(gemspec: parser_gemspec, out: nil)
+        # if this fails, you may not have run `bundle exec rbs collection update`
+        expect(Solargraph::Yardoc).not_to have_received(:build_docs).with(any_args)
+      end
+    end
+
+    context 'with an installed gem' do
+      before do
+        Solargraph::Shell.new.gems('kramdown')
+      end
+
+      it 'uncaches when asked' do
+        gemspec = Gem::Specification.find_by_name('kramdown')
+        expect do
+          pin_cache.uncache_gem(gemspec, out: nil)
+        end.not_to raise_error
+      end
+    end
+
+    context 'with the rebuild flag' do
+      before do
+        allow(Solargraph::Yardoc).to receive(:build_docs)
+      end
+
+      it 'chooses not to use YARD' do
+        parser_gemspec = Gem::Specification.find_by_name('parser')
+        pin_cache.cache_gem(gemspec: parser_gemspec, rebuild: true, out: nil)
+        # if this fails, you may not have run `bundle exec rbs collection update`
+        expect(Solargraph::Yardoc).not_to have_received(:build_docs).with(any_args)
+      end
+    end
+
+    context 'with a stdlib gem' do
+      let(:gem_name) { 'logger' }
+
+      before do
+        Solargraph::Shell.new.uncache(gem_name)
+      end
+
+      it 'caches' do
+        yaml_gemspec = Gem::Specification.find_by_name(gem_name)
+        allow(File).to receive(:write).and_call_original
+
+        pin_cache.cache_gem(gemspec: yaml_gemspec, out: nil)
+
+        # match arguments with regexp using rspec-matchers syntax
+        expect(File).to have_received(:write).with(%r{combined/.*/logger-.*-stdlib.ser$}, any_args).once
+      end
+    end
+
+    context 'with gem packaged with its own RBS gem' do
+      let(:gem_name) { 'base64' }
+
+      before do
+        Solargraph::Shell.new.uncache(gem_name)
+      end
+
+      it 'caches' do
+        yaml_gemspec = Gem::Specification.find_by_name(gem_name)
+        allow(File).to receive(:write).and_call_original
+
+        pin_cache.cache_gem(gemspec: yaml_gemspec, out: nil)
+
+        # match arguments with regexp using rspec-matchers syntax
+        expect(File).to have_received(:write).with(%r{combined/.*/base64-.*-export.ser$}, any_args, mode: 'wb').once
+      end
+    end
+  end
+
+  describe '#uncache_gem' do
+    subject(:call) { pin_cache.uncache_gem(gemspec, out: out) }
+
+    let(:out) { StringIO.new }
+
+    before do
+      allow(FileUtils).to receive(:rm_rf)
+    end
+
+    context 'with an already cached gem' do
+      let(:gemspec) { Gem::Specification.find_by_name('backport') }
+
+      it 'deletes files' do
+        call
+
+        expect(FileUtils).to have_received(:rm_rf).at_least(:once)
+      end
+    end
+
+    context 'with a non-existent gem' do
+      let(:gemspec) { instance_double(Gem::Specification, name: 'nonexistent', version: '0.0.1') }
+
+      it 'does not raise an error' do
+        expect { call }.not_to raise_error
+      end
+
+      it 'logs a message' do
+        call
+
+        expect(out.string).to include('does not exist')
+      end
+
+      it 'does not delete files' do
+        call
+
+        expect(FileUtils).not_to have_received(:rm_rf)
+      end
+    end
+  end
+end
diff --git a/spec/rbs_map/conversions_spec.rb b/spec/rbs_map/conversions_spec.rb
index 09c203687..00e75732b 100644
--- a/spec/rbs_map/conversions_spec.rb
+++ b/spec/rbs_map/conversions_spec.rb
@@ -1,54 +1,99 @@
 describe Solargraph::RbsMap::Conversions do
-  # create a temporary directory with the scope of the spec
-  around do |example|
-    require 'tmpdir'
-    Dir.mktmpdir("rspec-solargraph-") do |dir|
-      @temp_dir = dir
-      example.run
+  context 'with custom RBS files' do
+    # create a temporary directory with the scope of the spec
+    around do |example|
+      require 'tmpdir'
+      Dir.mktmpdir("rspec-solargraph-") do |dir|
+        @temp_dir = dir
+        example.run
+      end
     end
-  end
 
-  let(:rbs_repo) do
-    RBS::Repository.new(no_stdlib: false)
-  end
+    let(:rbs_repo) do
+      RBS::Repository.new(no_stdlib: false)
+    end
 
-  let(:loader) do
-    RBS::EnvironmentLoader.new(core_root: nil, repository: rbs_repo)
-  end
+    let(:loader) do
+      RBS::EnvironmentLoader.new(core_root: nil, repository: rbs_repo)
+    end
 
-  let(:conversions) do
-    Solargraph::RbsMap::Conversions.new(loader: loader)
-  end
+    let(:conversions) do
+      Solargraph::RbsMap::Conversions.new(loader: loader)
+    end
 
-  let(:pins) do
-    conversions.pins
-  end
+    let(:pins) do
+      conversions.pins
+    end
 
-  before do
-    rbs_file = File.join(temp_dir, 'foo.rbs')
-    File.write(rbs_file, rbs)
-    loader.add(path: Pathname(temp_dir))
-  end
+    before do
+      rbs_file = File.join(temp_dir, 'foo.rbs')
+      File.write(rbs_file, rbs)
+      loader.add(path: Pathname(temp_dir))
+    end
 
-  attr_reader :temp_dir
+    attr_reader :temp_dir
 
-  context 'with untyped response' do
-    let(:rbs) do
-      <<~RBS
+    context 'with untyped response' do
+      let(:rbs) do
+        <<~RBS
           class Foo
             def bar: () -> untyped
           end
         RBS
+      end
+
+      subject(:method_pin) { pins.find { |pin| pin.path == 'Foo#bar' } }
+
+      it { should_not be_nil }
+
+      it { should be_a(Solargraph::Pin::Method) }
+
+      it 'maps untyped in RBS to undefined in Solargraph 'do
+        expect(method_pin.return_type.tag).to eq('undefined')
+      end
+    end
+  end
+
+  context 'with standard loads for solargraph project' do
+    before :all do # rubocop:disable RSpec/BeforeAfterAll
+      @api_map = Solargraph::ApiMap.load_with_cache('.')
     end
 
-    subject(:method_pin) { pins.find { |pin| pin.path == 'Foo#bar' } }
+    let(:api_map) { @api_map } # rubocop:disable RSpec/InstanceVariable
+
+    context 'with superclass pin for Parser::AST::Node' do
+      let(:superclass_pin) do
+        api_map.pins.find do |pin|
+          pin.is_a?(Solargraph::Pin::Reference::Superclass) && pin.context.namespace == 'Parser::AST::Node'
+        end
+      end
+
+      it 'generates a rooted pin' do
+        # rooted!
+        expect(superclass_pin&.name).to eq('::AST::Node')
+      end
+    end
+  end
+
+  if Gem::Version.new(RBS::VERSION) >= Gem::Version.new('3.9.1')
+    context 'with method pin for Open3.capture2e' do
+      let(:api_map) { Solargraph::ApiMap.load_with_cache('.') }
 
-    it { should_not be_nil }
+      let(:method_pin) do
+        api_map.pins.find do |pin|
+          pin.is_a?(Solargraph::Pin::Method) && pin.path == 'Open3.capture2e'
+        end
+      end
 
-    it { should be_a(Solargraph::Pin::Method) }
+      let(:chdir_param) do
+        method_pin&.signatures&.flat_map(&:parameters)&.find do |param| # rubocop:disable Style/SafeNavigationChainLength
+          param.name == 'chdir'
+        end
+      end
 
-    it 'maps untyped in RBS to undefined in Solargraph 'do
-      expect(method_pin.return_type.tag).to eq('undefined')
+      it 'accepts chdir kwarg' do
+        expect(chdir_param).not_to be_nil, -> { "Found pin #{method_pin.to_rbs} from #{method_pin.type_location}" }
+      end
     end
   end
 end
diff --git a/spec/rbs_map/core_map_spec.rb b/spec/rbs_map/core_map_spec.rb
index 352d29937..88590925b 100644
--- a/spec/rbs_map/core_map_spec.rb
+++ b/spec/rbs_map/core_map_spec.rb
@@ -6,7 +6,7 @@
       pin = store.get_path_pins("Errno::#{const}").first
       expect(pin).to be_a(Solargraph::Pin::Namespace)
       superclass = store.get_superclass(pin.path)
-      expect(superclass).to eq('SystemCallError')
+      expect(superclass).to eq('::SystemCallError')
     end
   end
 
diff --git a/spec/rbs_map_spec.rb b/spec/rbs_map_spec.rb
index b06c975d1..f3ca90a36 100644
--- a/spec/rbs_map_spec.rb
+++ b/spec/rbs_map_spec.rb
@@ -3,7 +3,18 @@
     spec = Gem::Specification.find_by_name('rbs')
     rbs_map = Solargraph::RbsMap.from_gemspec(spec, nil, nil)
     pin = rbs_map.path_pin('RBS::EnvironmentLoader#add_collection')
-    expect(pin).to be
+    expect(pin).not_to be_nil
+  end
+
+  it 'fails if it does not find data from gemspec' do
+    spec = Gem::Specification.find_by_name('backport')
+    rbs_map = Solargraph::RbsMap.from_gemspec(spec, nil, nil)
+    expect(rbs_map).not_to be_resolved
+  end
+
+  it 'fails if it does not find data from name' do
+    rbs_map = Solargraph::RbsMap.new('lskdflaksdfjl')
+    expect(rbs_map.pins).to be_empty
   end
 
   it 'converts constants and aliases to correct types' do
diff --git a/spec/shell_spec.rb b/spec/shell_spec.rb
index 91f84b4c7..0d48bfb97 100644
--- a/spec/shell_spec.rb
+++ b/spec/shell_spec.rb
@@ -1,7 +1,10 @@
+# frozen_string_literal: true
+
 require 'tmpdir'
 require 'open3'
 
 describe Solargraph::Shell do
+  let(:shell) { described_class.new }
   let(:temp_dir) { Dir.mktmpdir }
 
   before do
@@ -25,20 +28,294 @@ def bundle_exec(*cmd)
     FileUtils.rm_rf(temp_dir)
   end
 
-  describe "--version" do
-    it "returns a version when run" do
-      output = bundle_exec("solargraph", "--version")
+  describe '--version' do
+    let(:output) { bundle_exec('solargraph', '--version') }
 
+    it 'returns output' do
       expect(output).not_to be_empty
+    end
+
+    it 'returns a version when run' do
       expect(output).to eq("#{Solargraph::VERSION}\n")
     end
   end
 
-  describe "uncache" do
-    it "uncaches without erroring out" do
-      output = bundle_exec("solargraph", "uncache", "solargraph")
+  describe 'uncache' do
+    it 'uncaches without erroring out' do
+      output = capture_stdout do
+        shell.uncache('backport')
+      end
 
       expect(output).to include('Clearing pin cache in')
     end
+
+    it 'uncaches stdlib without erroring out' do
+      expect { shell.uncache('stdlib') }.not_to raise_error
+    end
+
+    it 'uncaches core without erroring out' do
+      expect { shell.uncache('core') }.not_to raise_error
+    end
+  end
+
+  describe 'scan' do
+    context 'with mocked dependencies' do
+      let(:api_map) { instance_double(Solargraph::ApiMap) }
+
+      before do
+        allow(Solargraph::ApiMap).to receive(:load_with_cache).and_return(api_map)
+      end
+
+      it 'scans without erroring out' do
+        allow(api_map).to receive(:pins).and_return([])
+        output = capture_stdout do
+          shell.options = { directory: 'spec/fixtures/workspace' }
+          shell.scan
+        end
+
+        expect(output).to include('Scanned ').and include(' seconds.')
+      end
+    end
+  end
+
+  describe 'typecheck' do
+    context 'with mocked dependencies' do
+      let(:type_checker) { instance_double(Solargraph::TypeChecker) }
+      let(:api_map) { instance_double(Solargraph::ApiMap) }
+
+      before do
+        allow(Solargraph::ApiMap).to receive(:load_with_cache).and_return(api_map)
+        allow(Solargraph::TypeChecker).to receive(:new).and_return(type_checker)
+        allow(type_checker).to receive(:problems).and_return([])
+      end
+
+      it 'typechecks without erroring out' do
+        output = capture_stdout do
+          shell.options = { level: 'normal', directory: '.' }
+          shell.typecheck('Gemfile')
+        end
+
+        expect(output).to include('Typecheck finished in')
+      end
+    end
+  end
+
+  describe 'gems' do
+    context 'without mocked ApiMap' do
+      it 'complains when gem does not exist' do
+        output = capture_both do
+          shell.gems('nonexistentgem')
+        end
+
+        expect(output).to include("Gem 'nonexistentgem' not found")
+      end
+
+      it 'caches core without erroring out' do
+        capture_both do
+          shell.uncache('core')
+        end
+
+        expect { shell.cache('core') }.not_to raise_error
+      end
+
+      it 'gives sensible error for gem that does not exist' do
+        output = capture_both do
+          shell.gems('solargraph123')
+        end
+
+        expect(output).to include("Gem 'solargraph123' not found")
+      end
+    end
+
+    context 'with mocked Workspace' do
+      let(:workspace) { instance_double(Solargraph::Workspace) }
+      let(:gemspec) { instance_double(Gem::Specification, name: 'backport') }
+
+      before do
+        allow(Solargraph::Workspace).to receive(:new).and_return(workspace)
+      end
+
+      it 'caches all without erroring out' do
+        allow(workspace).to receive(:cache_all_for_workspace!)
+
+        _output = capture_both { shell.gems }
+
+        expect(workspace).to have_received(:cache_all_for_workspace!)
+      end
+
+      it 'caches single gem without erroring out' do
+        allow(workspace).to receive(:find_gem).with('backport').and_return(gemspec)
+        allow(workspace).to receive(:cache_gem)
+
+        capture_both do
+          shell.options = { rebuild: false }
+          shell.gems('backport')
+        end
+
+        expect(workspace).to have_received(:cache_gem).with(gemspec, out: an_instance_of(StringIO), rebuild: false)
+      end
+    end
+  end
+
+  describe 'cache' do
+    it 'caches a stdlib gem without erroring out' do
+      expect { shell.cache('stringio') }.not_to raise_error
+    end
+
+    context 'when gem does not exist' do
+      subject(:call) { shell.cache('nonexistentgem8675309') }
+
+      it 'gives a good error message' do
+        # capture stderr output
+        expect { call }.to output(/not found/).to_stderr
+      end
+    end
+  end
+
+  describe 'method_pin' do
+    let(:api_map) { instance_double(Solargraph::ApiMap) }
+    let(:to_s_pin) { instance_double(Solargraph::Pin::Method, return_type: Solargraph::ComplexType.parse('String')) }
+
+    before do
+      allow(Solargraph::ApiMap).to receive(:load_with_cache).and_return(api_map)
+      allow(api_map).to receive(:get_path_pins).with('String#to_s').and_return([to_s_pin])
+    end
+
+    context 'with no options' do
+      it 'prints a pin' do
+        allow(to_s_pin).to receive(:inspect).and_return('pin inspect result')
+
+        out = capture_both { shell.method_pin('String#to_s') }
+
+        expect(out).to eq("pin inspect result\n")
+      end
+    end
+
+    context 'with --rbs option' do
+      it 'prints a pin with RBS type' do
+        allow(to_s_pin).to receive(:to_rbs).and_return('pin RBS result')
+
+        out = capture_both do
+          shell.options = { rbs: true }
+          shell.method_pin('String#to_s')
+        end
+        expect(out).to eq("pin RBS result\n")
+      end
+    end
+
+    context 'with --stack option' do
+      it 'prints a pin using stack results' do
+        allow(to_s_pin).to receive(:to_rbs).and_return('pin RBS result')
+
+        allow(api_map).to receive(:get_method_stack).and_return([to_s_pin])
+        capture_both do
+          shell.options = { stack: true }
+          shell.method_pin('String#to_s')
+        end
+        expect(api_map).to have_received(:get_method_stack).with('String', 'to_s', scope: :instance)
+      end
+
+      it 'prints a static pin using stack results' do
+        # allow(to_s_pin).to receive(:to_rbs).and_return('pin RBS result')
+        string_new_pin = instance_double(Solargraph::Pin::Method, return_type: Solargraph::ComplexType.parse('String'))
+
+        allow(api_map).to receive(:get_method_stack).with('String', 'new', scope: :class).and_return([string_new_pin])
+        capture_both do
+          shell.options = { stack: true }
+          shell.method_pin('String.new')
+        end
+        expect(api_map).to have_received(:get_method_stack).with('String', 'new', scope: :class)
+      end
+    end
+
+    context 'with --typify option' do
+      it 'prints a pin with typify type' do
+        allow(to_s_pin).to receive(:typify).and_return(Solargraph::ComplexType.parse('::String'))
+
+        out = capture_both do
+          shell.options = { typify: true }
+          shell.method_pin('String#to_s')
+        end
+        expect(out).to eq("::String\n")
+      end
+    end
+
+    context 'with --typify --rbs options' do
+      it 'prints a pin with typify type' do
+        allow(to_s_pin).to receive(:typify).and_return(Solargraph::ComplexType.parse('::String'))
+
+        out = capture_both do
+          shell.options = { typify: true, rbs: true }
+          shell.method_pin('String#to_s')
+        end
+        expect(out).to eq("::String\n")
+      end
+    end
+
+    context 'with no pin' do
+      it 'prints error' do
+        allow(api_map).to receive(:get_path_pins).with('Not#found').and_return([])
+
+        out = capture_both do
+          shell.options = {}
+          shell.method_pin('Not#found')
+        rescue SystemExit
+          # Ignore the SystemExit raised by the shell when no pin is found
+        end
+        expect(out).to include("Pin not found for path 'Not#found'")
+      end
+    end
+  end
+
+  describe 'rbs' do
+    let(:api_map) { instance_double(Solargraph::ApiMap) }
+
+    before do
+      allow(shell).to receive(:`)
+      allow(Solargraph::ApiMap).to receive(:load).and_return(api_map)
+      allow(api_map).to receive(:source_maps).and_return(source_maps)
+    end
+
+    context 'without inference' do
+      let(:source_maps) { [] }
+
+      it 'invokes sord' do
+        capture_both do
+          shell.options = { filename: 'foo.rbs' }
+          shell.rbs
+        end
+        expect(shell)
+          .to have_received(:`)
+          .with("sord #{Dir.pwd}/sig/foo.rbs --rbs --no-regenerate")
+      end
+    end
+
+    context 'with inference' do
+      let(:source_maps) { [source_map] }
+      let(:source_map) { instance_double(Solargraph::SourceMap) }
+      let(:pin) do
+        instance_double(Solargraph::Pin::Method,
+                        namespace: 'My::Namespace', path: 'My::Namespace#foo',
+                        visibility: :public,
+                        parameters: [],
+                        scope: :instance,
+                        location: nil,
+                        name: 'foo',
+                        class: Solargraph::Pin::Method,
+                        return_type: Solargraph::ComplexType::UNDEFINED)
+      end
+
+      it 'infers unknown types on pins' do
+        allow(source_map).to receive(:pins).and_return([pin])
+        allow(pin).to receive_messages(typify: Solargraph::ComplexType.parse('String'),
+                                       docstring: YARD::Docstring.new(''))
+        allow(pin).to receive(:code_object).and_return(nil)
+        capture_both do
+          shell.options = { filename: 'foo.rbs', inference: true }
+          shell.rbs
+        end
+        expect(pin).to have_received(:typify)
+      end
+    end
   end
 end
diff --git a/spec/source_map/clip_spec.rb b/spec/source_map/clip_spec.rb
index 0f83331ec..788380478 100644
--- a/spec/source_map/clip_spec.rb
+++ b/spec/source_map/clip_spec.rb
@@ -302,6 +302,23 @@ def foo
     expect(type.tag).to eq('String')
   end
 
+  it 'infers method types from return nodes' do
+    source = Solargraph::Source.load_string(%(
+      class Foo
+        # @return [self]
+        def foo
+          bar
+        end
+      end
+      Foo.new.foo
+    ), 'test.rb')
+    map = Solargraph::ApiMap.new
+    map.map source
+    clip = map.clip_at('test.rb', Solargraph::Position.new(7, 10))
+    type = clip.infer
+    expect(type.tag).to eq('Foo')
+  end
+
   it 'infers multiple method types from return nodes' do
     source = Solargraph::Source.load_string(%(
       def foo
@@ -1644,10 +1661,12 @@ def foo; end
     api_map = Solargraph::ApiMap.new.map(source)
 
     array_names = api_map.clip_at('test.rb', [5, 22]).complete.pins.map(&:name)
-    expect(array_names).to eq(["byteindex", "byterindex", "bytes", "bytesize", "byteslice", "bytesplice"])
+    # other methods may come in via plugin default requires
+    expect(array_names).to include("byteindex", "byterindex", "bytes", "bytesize", "byteslice", "bytesplice")
 
     string_names = api_map.clip_at('test.rb', [6, 22]).complete.pins.map(&:name)
-    expect(string_names).to eq(['upcase', 'upcase!', 'upto'])
+    # other methods may come in via plugin default requires
+    expect(string_names).to include('upcase', 'upcase!', 'upto')
   end
 
   it 'completes global methods defined in top level scope inside class when referenced inside a namespace' do
diff --git a/spec/source_map/mapper_spec.rb b/spec/source_map/mapper_spec.rb
index af3678cfd..96d2bdab5 100644
--- a/spec/source_map/mapper_spec.rb
+++ b/spec/source_map/mapper_spec.rb
@@ -1525,9 +1525,9 @@ def bar; end
         def quz; end
       end
     ))
-    expect(map.first_pin('Foo#bar').visibility).to be(:public)
-    expect(map.first_pin('Foo#baz').visibility).to be(:private)
-    expect(map.first_pin('Foo#quz').visibility).to be(:public)
+    expect(map.first_pin('Foo#bar').visibility).to eq(:public)
+    expect(map.first_pin('Foo#baz').visibility).to eq(:private)
+    expect(map.first_pin('Foo#quz').visibility).to eq(:public)
   end
 
   it 'encloses class_eval calls in receivers' do
diff --git a/spec/source_map_spec.rb b/spec/source_map_spec.rb
index 398355075..b634491e4 100644
--- a/spec/source_map_spec.rb
+++ b/spec/source_map_spec.rb
@@ -72,7 +72,7 @@ class Foo
         end
       end
     ))
-    pin = map.locate_block_pin(3, 0)
+    pin = map.locate_closure_pin(3, 0)
     expect(pin).to be_a(Solargraph::Pin::Block)
   end
 
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 00cc6c8c3..5e3879a67 100755
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,11 +1,14 @@
 require 'bundler/setup'
 require 'webmock/rspec'
+require 'rspec_time_guard'
 WebMock.disable_net_connect!(allow_localhost: true)
 unless ENV['SIMPLECOV_DISABLED']
   # set up lcov reporting for undercover
   require 'simplecov'
+  require 'simplecov-lcov'
   require 'undercover/simplecov_formatter'
-
+  SimpleCov::Formatter::LcovFormatter.config.report_with_single_file = true
+  SimpleCov.formatter = SimpleCov::Formatter::LcovFormatter
   SimpleCov.start do
     cname = ENV.fetch('TEST_COVERAGE_COMMAND_NAME', 'ad-hoc')
     command_name cname
@@ -25,8 +28,16 @@
   # Allow use of --only-failures with rspec, handy for local development
   c.example_status_persistence_file_path = 'rspec-examples.txt'
 end
+RspecTimeGuard.setup
+RspecTimeGuard.configure do |config|
+  config.global_time_limit_seconds = 60
+  config.continue_on_timeout = false
+end
+
 require 'solargraph'
-# Suppress logger output in specs (if possible)
+# execute any logging blocks to make sure they don't blow up
+Solargraph::Logging.logger.sev_threshold = Logger::DEBUG
+# ...but still suppress logger output in specs (if possible)
 if Solargraph::Logging.logger.respond_to?(:reopen) && !ENV.key?('SOLARGRAPH_LOG')
   Solargraph::Logging.logger.reopen(File::NULL)
 end
@@ -43,3 +54,29 @@ def with_env_var(name, value)
     ENV[name] = old_value  # Restore the old value
   end
 end
+
+def capture_stdout &block
+  original_stdout = $stdout
+  $stdout = StringIO.new
+  begin
+    block.call
+    $stdout.string
+  ensure
+    $stdout = original_stdout
+  end
+end
+
+def capture_both &block
+  original_stdout = $stdout
+  original_stderr = $stderr
+  stringio = StringIO.new
+  $stdout = stringio
+  $stderr = stringio
+  begin
+    block.call
+  ensure
+    $stdout = original_stdout
+    $stderr = original_stderr
+  end
+  stringio.string
+end
diff --git a/spec/type_checker/checks_spec.rb b/spec/type_checker/checks_spec.rb
deleted file mode 100644
index 41119cefd..000000000
--- a/spec/type_checker/checks_spec.rb
+++ /dev/null
@@ -1,146 +0,0 @@
-describe Solargraph::TypeChecker::Checks do
-  it 'validates simple core types' do
-    api_map = Solargraph::ApiMap.new
-    exp = Solargraph::ComplexType.parse('String')
-    inf = Solargraph::ComplexType.parse('String')
-    match = Solargraph::TypeChecker::Checks.types_match?(api_map, exp, inf)
-    expect(match).to be(true)
-  end
-
-  it 'invalidates simple core types' do
-    api_map = Solargraph::ApiMap.new
-    exp = Solargraph::ComplexType.parse('String')
-    inf = Solargraph::ComplexType.parse('Integer')
-    match = Solargraph::TypeChecker::Checks.types_match?(api_map, exp, inf)
-    expect(match).to be(false)
-  end
-
-  it 'validates expected superclasses' do
-    source = Solargraph::Source.load_string(%(
-      class Sup; end
-      class Sub < Sup; end
-    ))
-    api_map = Solargraph::ApiMap.new
-    api_map.map source
-    sup = Solargraph::ComplexType.parse('Sup')
-    sub = Solargraph::ComplexType.parse('Sub')
-    match = Solargraph::TypeChecker::Checks.types_match?(api_map, sup, sub)
-    expect(match).to be(true)
-  end
-
-  it 'invalidates inferred superclasses (expected must be super)' do
-    # @todo This test might be invalid. There are use cases where inheritance
-    #   between inferred and expected classes should be acceptable in either
-    #   direction.
-    # source = Solargraph::Source.load_string(%(
-    #   class Sup; end
-    #   class Sub < Sup; end
-    # ))
-    # api_map = Solargraph::ApiMap.new
-    # api_map.map source
-    # sup = Solargraph::ComplexType.parse('Sup')
-    # sub = Solargraph::ComplexType.parse('Sub')
-    # match = Solargraph::TypeChecker::Checks.types_match?(api_map, sub, sup)
-    # expect(match).to be(false)
-  end
-
-  it 'fuzzy matches arrays with parameters' do
-    api_map = Solargraph::ApiMap.new
-    exp = Solargraph::ComplexType.parse('Array')
-    inf = Solargraph::ComplexType.parse('Array<String>')
-    match = Solargraph::TypeChecker::Checks.types_match?(api_map, exp, inf)
-    expect(match).to be(true)
-  end
-
-  it 'fuzzy matches sets with parameters' do
-    source = Solargraph::Source.load_string("require 'set'")
-    source_map = Solargraph::SourceMap.map(source)
-    api_map = Solargraph::ApiMap.new
-    api_map.catalog Solargraph::Bench.new(source_maps: [source_map], external_requires: ['set'])
-    exp = Solargraph::ComplexType.parse('Set')
-    inf = Solargraph::ComplexType.parse('Set<String>')
-    match = Solargraph::TypeChecker::Checks.types_match?(api_map, exp, inf)
-    expect(match).to be(true)
-  end
-
-  it 'fuzzy matches hashes with parameters' do
-    api_map = Solargraph::ApiMap.new
-    exp = Solargraph::ComplexType.parse('Hash{ Symbol => String}')
-    inf = Solargraph::ComplexType.parse('Hash')
-    match = Solargraph::TypeChecker::Checks.types_match?(api_map, exp, inf)
-    expect(match).to be(true)
-  end
-
-  it 'matches multiple types' do
-    api_map = Solargraph::ApiMap.new
-    exp = Solargraph::ComplexType.parse('String, Integer')
-    inf = Solargraph::ComplexType.parse('String, Integer')
-    match = Solargraph::TypeChecker::Checks.types_match?(api_map, exp, inf)
-    expect(match).to be(true)
-  end
-
-  it 'matches multiple types out of order' do
-    api_map = Solargraph::ApiMap.new
-    exp = Solargraph::ComplexType.parse('String, Integer')
-    inf = Solargraph::ComplexType.parse('Integer, String')
-    match = Solargraph::TypeChecker::Checks.types_match?(api_map, exp, inf)
-    expect(match).to be(true)
-  end
-
-  it 'invalidates inferred types missing from expected' do
-    api_map = Solargraph::ApiMap.new
-    exp = Solargraph::ComplexType.parse('String')
-    inf = Solargraph::ComplexType.parse('String, Integer')
-    match = Solargraph::TypeChecker::Checks.types_match?(api_map, exp, inf)
-    expect(match).to be(false)
-  end
-
-  it 'matches nil' do
-    api_map = Solargraph::ApiMap.new
-    exp = Solargraph::ComplexType.parse('nil')
-    inf = Solargraph::ComplexType.parse('nil')
-    match = Solargraph::TypeChecker::Checks.types_match?(api_map, exp, inf)
-    expect(match).to be(true)
-  end
-
-  it 'validates classes with expected superclasses' do
-    api_map = Solargraph::ApiMap.new
-    exp = Solargraph::ComplexType.parse('Class<Object>')
-    inf = Solargraph::ComplexType.parse('Class<String>')
-    match = Solargraph::TypeChecker::Checks.types_match?(api_map, exp, inf)
-    expect(match).to be(true)
-  end
-
-  it 'validates generic classes with expected Class' do
-    api_map = Solargraph::ApiMap.new
-    exp = Solargraph::ComplexType.parse('Class<String>')
-    inf = Solargraph::ComplexType.parse('Class')
-    match = Solargraph::TypeChecker::Checks.types_match?(api_map, exp, inf)
-    expect(match).to be(true)
-  end
-
-  it 'validates inheritance in both directions' do
-    source = Solargraph::Source.load_string(%(
-      class Sup; end
-      class Sub < Sup; end
-    ))
-    api_map = Solargraph::ApiMap.new
-    api_map.map source
-    sup = Solargraph::ComplexType.parse('Sup')
-    sub = Solargraph::ComplexType.parse('Sub')
-    match = Solargraph::TypeChecker::Checks.either_way?(api_map, sup, sub)
-    expect(match).to be(true)
-    match = Solargraph::TypeChecker::Checks.either_way?(api_map, sub, sup)
-    expect(match).to be(true)
-  end
-
-  it 'invalidates inheritance in both directions' do
-    api_map = Solargraph::ApiMap.new
-    sup = Solargraph::ComplexType.parse('String')
-    sub = Solargraph::ComplexType.parse('Array')
-    match = Solargraph::TypeChecker::Checks.either_way?(api_map, sup, sub)
-    expect(match).to be(false)
-    match = Solargraph::TypeChecker::Checks.either_way?(api_map, sub, sup)
-    expect(match).to be(false)
-  end
-end
diff --git a/spec/type_checker/levels/alpha_spec.rb b/spec/type_checker/levels/alpha_spec.rb
new file mode 100644
index 000000000..3ff5aa6c3
--- /dev/null
+++ b/spec/type_checker/levels/alpha_spec.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+describe Solargraph::TypeChecker do
+  context 'when at alpha level' do
+    def type_checker code
+      Solargraph::TypeChecker.load_string(code, 'test.rb', :alpha)
+    end
+
+    it 'reports nilable type issues' do
+      checker = type_checker(%(
+        # @param a [String]
+        # @return [void]
+        def foo(a); end
+
+        # @param b [String, nil]
+        # @return [void]
+        def bar(b)
+         foo(b)
+        end
+      ))
+      expect(checker.problems.map(&:message))
+        .to eq(['Wrong argument type for #foo: a expected String, received String, nil'])
+    end
+  end
+end
diff --git a/spec/type_checker/levels/normal_spec.rb b/spec/type_checker/levels/normal_spec.rb
index 3b38f55d8..0b3024f62 100644
--- a/spec/type_checker/levels/normal_spec.rb
+++ b/spec/type_checker/levels/normal_spec.rb
@@ -1,5 +1,5 @@
 describe Solargraph::TypeChecker do
-  context 'normal level' do
+  context 'when checking at normal level' do
     def type_checker(code)
       Solargraph::TypeChecker.load_string(code, 'test.rb', :normal)
     end
@@ -221,9 +221,9 @@ def bar; end
       # @todo This test uses kramdown-parser-gfm because it's a gem dependency known to
       #   lack typed methods. A better test wouldn't depend on the state of
       #   vendored code.
+      workspace = Solargraph::Workspace.new(Dir.pwd)
       gemspec = Gem::Specification.find_by_name('kramdown-parser-gfm')
-      yard_pins = Solargraph::GemPins.build_yard_pins([], gemspec)
-      Solargraph::PinCache.serialize_yard_gem(gemspec, yard_pins)
+      workspace.cache_gem(gemspec)
 
       checker = type_checker(%(
         require 'kramdown-parser-gfm'
diff --git a/spec/type_checker/levels/strict_spec.rb b/spec/type_checker/levels/strict_spec.rb
index b198cec89..aac5c1ece 100644
--- a/spec/type_checker/levels/strict_spec.rb
+++ b/spec/type_checker/levels/strict_spec.rb
@@ -1,5 +1,5 @@
 describe Solargraph::TypeChecker do
-  context 'strict level' do
+  context 'when checking at strict level' do
     # @return [Solargraph::TypeChecker]
     def type_checker(code)
       Solargraph::TypeChecker.load_string(code, 'test.rb', :strict)
@@ -59,7 +59,7 @@ def bar(a); end
         require 'kramdown-parser-gfm'
         Kramdown::Parser::GFM.undefined_call
       ), 'test.rb')
-      api_map = Solargraph::ApiMap.load_with_cache('.', $stdout)
+      api_map = Solargraph::ApiMap.load '.'
       api_map.catalog Solargraph::Bench.new(source_maps: [source_map], external_requires: ['kramdown-parser-gfm'])
       checker = Solargraph::TypeChecker.new('test.rb', api_map: api_map, level: :strict)
       expect(checker.problems).to be_empty
@@ -115,6 +115,39 @@ def bar(baz); end
       expect(checker.problems.first.message).to include('Wrong argument type')
     end
 
+    it 'reports mismatched argument types in chained calls' do
+      checker = type_checker(%(
+        # @param baz [Integer]
+        # @return [String]
+        def bar(baz); "foo"; end
+        bar('string').upcase
+      ))
+      expect(checker.problems).to be_one
+      expect(checker.problems.first.message).to include('Wrong argument type')
+    end
+
+    it 'reports mismatched argument types in calls inside array literals' do
+      checker = type_checker(%(
+        # @param baz [Integer]
+        # @return [String]
+        def bar(baz); "foo"; end
+        [ bar('string') ]
+      ))
+      expect(checker.problems).to be_one
+      expect(checker.problems.first.message).to include('Wrong argument type')
+    end
+
+    it 'reports mismatched argument types in calls inside array literals used in a chain' do
+      checker = type_checker(%(
+        # @param baz [Integer]
+        # @return [String]
+        def bar(baz); "foo"; end
+        [ bar('string') ].compact
+      ))
+      expect(checker.problems).to be_one
+      expect(checker.problems.first.message).to include('Wrong argument type')
+    end
+
     xit 'complains about calling a private method from an illegal place'
 
     xit 'complains about calling a non-existent method'
@@ -126,7 +159,7 @@ def foo(a)
           a[0] = :something
         end
       ))
-      expect(checker.problems.map(&:problems)).to eq(['Wrong argument type'])
+      expect(checker.problems.map(&:message)).to eq(['Wrong argument type'])
     end
 
     it 'complains about dereferencing a non-existent tuple slot'
@@ -666,6 +699,19 @@ def test(foo: nil)
       expect(checker.problems).to be_empty
     end
 
+
+    it 'validates parameters in function calls' do
+      checker = type_checker(%(
+        # @param bar [String]
+        def foo(bar); end
+
+        def baz
+          foo(123)
+        end
+        ))
+      expect(checker.problems.map(&:message)).to eq(['Wrong argument type for #foo: bar expected String, received 123'])
+    end
+
     it 'validates inferred return types with complex tags' do
       checker = type_checker(%(
         # @param foo [Numeric, nil] a foo
@@ -814,6 +860,23 @@ def foo *path, baz; end
       expect(checker.problems.map(&:message)).to eq([])
     end
 
+    it "understands enough of define_method not to think the block is in class scope" do
+      checker = type_checker(%(
+        class Foo
+          def initialize
+            @resolved_method = nil
+          end
+
+          def bar
+          end
+
+          define_method('a') do
+            bar
+          end
+        end
+      ))
+      expect(checker.problems.map(&:message)).to eq([])
+    end
 
     it 'understands tuple superclass' do
       checker = type_checker(%(
@@ -941,5 +1004,22 @@ def bar(a)
       ))
       expect(checker.problems.map(&:message)).to eq([])
     end
+
+    it 'does not complain on defaulted reader with detailed expression' do
+      checker = type_checker(%(
+        class Foo
+          # @return [Integer, nil]
+          def bar
+            @bar ||=
+              if rand
+                 123
+               elsif rand
+                 456
+               end
+          end
+        end
+      ))
+      expect(checker.problems.map(&:message)).to eq([])
+    end
   end
 end
diff --git a/spec/type_checker/levels/strong_spec.rb b/spec/type_checker/levels/strong_spec.rb
index 6fdf84e30..36988adbe 100644
--- a/spec/type_checker/levels/strong_spec.rb
+++ b/spec/type_checker/levels/strong_spec.rb
@@ -1,5 +1,5 @@
 describe Solargraph::TypeChecker do
-  context 'strong level' do
+  context 'when tracking at strong level' do
     def type_checker(code)
       Solargraph::TypeChecker.load_string(code, 'test.rb', :strong)
     end
@@ -15,6 +15,48 @@ def bar; end
       expect(checker.problems.map(&:message)).to eq(['Unneeded @sg-ignore comment'])
     end
 
+    it 'does not complain on array dereference' do
+      checker = type_checker(%(
+        # @param idx [Integer, nil] an index
+        # @param arr [Array<Integer>] an array of integers
+        #
+        # @return [void]
+        def foo(idx, arr)
+          arr[idx]
+        end
+      ))
+      expect(checker.problems.map(&:message)).to be_empty
+    end
+
+    it 'complains on bad @type assignment' do
+      checker = type_checker(%(
+        # @type [Integer]
+        c = Class.new
+      ))
+      expect(checker.problems.map(&:message))
+        .to eq ['Declared type Integer does not match inferred type Class for variable c']
+    end
+
+    it 'does not complain on another variant of Class.new' do
+      checker = type_checker(%(
+        class Class
+          # @return [self]
+          def self.blah
+            new
+          end
+        end
+      ))
+      expect(checker.problems.map(&:message)).to be_empty
+    end
+
+    it 'does not complain on indirect Class.new', skip: 'hangs in a loop currently' do
+      checker = type_checker(%(
+        class Foo < Class; end
+        Foo.new
+      ))
+      expect(checker.problems.map(&:message)).to be_empty
+    end
+
     it 'reports missing return tags' do
       checker = type_checker(%(
         class Foo
@@ -25,6 +67,69 @@ def bar; end
       expect(checker.problems.first.message).to include('Missing @return tag')
     end
 
+    it 'ignores nilable type issues' do
+      checker = type_checker(%(
+        # @param a [String]
+        # @return [void]
+        def foo(a); end
+
+        # @param b [String, nil]
+        # @return [void]
+        def bar(b)
+         foo(b)
+        end
+      ))
+      expect(checker.problems.map(&:message)).to eq([])
+    end
+
+    it 'calls out keyword issues even when required arg count matches' do
+      checker = type_checker(%(
+        # @param a [String]
+        # @param b [String]
+        # @return [void]
+        def foo(a = 'foo', b:); end
+
+        # @return [void]
+        def bar
+         foo('baz')
+        end
+      ))
+      expect(checker.problems.map(&:message)).to include('Call to #foo is missing keyword argument b')
+    end
+
+    it 'calls out type issues even when keyword issues are there' do
+      pending('fixes to arg vs param checking algorithm')
+
+      checker = type_checker(%(
+        # @param a [String]
+        # @param b [String]
+        # @return [void]
+        def foo(a = 'foo', b:); end
+
+        # @return [void]
+        def bar
+         foo(123)
+        end
+      ))
+      expect(checker.problems.map(&:message))
+        .to include('Wrong argument type for #foo: a expected String, received 123')
+    end
+
+    it 'calls out keyword issues even when arg type issues are there' do
+      checker = type_checker(%(
+        # @param a [String]
+        # @param b [String]
+        # @return [void]
+        def foo(a = 'foo', b:); end
+
+        # @return [void]
+        def bar
+         foo(123)
+        end
+      ))
+      expect(checker.problems.map(&:message)).to include('Call to #foo is missing keyword argument b')
+    end
+
     it 'reports missing param tags' do
       checker = type_checker(%(
         class Foo
@@ -136,6 +241,149 @@ def bar &block
       expect(checker.problems).to be_empty
     end
 
+    it 'does not need fully specified container types' do
+      checker = type_checker(%(
+        class Foo
+          # @param foo [Array<String>]
+          # @return [void]
+          def bar foo: []; end
+
+          # @param bing [Array]
+          # @return [void]
+          def baz(bing)
+            bar(foo: bing)
+            generic_values = [1,2,3].map(&:to_s)
+            bar(foo: generic_values)
+          end
+        end
+      ))
+      expect(checker.problems.map(&:message)).to be_empty
+    end
+
+    it 'treats a parameter type of undefined as not provided' do
+      checker = type_checker(%(
+        class Foo
+          # @param foo [Array<String>]
+          # @return [void]
+          def bar foo: []; end
+
+          # @param bing [Array<undefind>]
+          # @return [void]
+          def baz(bing)
+            bar(foo: bing)
+            generic_values = [1,2,3].map(&:to_s)
+            bar(foo: generic_values)
+          end
+        end
+      ))
+      expect(checker.problems.map(&:message)).to be_empty
+    end
+
+    it 'ignores generic resolution failure with no generic tag' do
+      checker = type_checker(%(
+        class Foo
+          # @param foo [Class<String>]
+          # @return [void]
+          def bar foo:; end
+
+          # @param bing [Class<generic<T>>]
+          # @return [void]
+          def baz(bing)
+            bar(foo: bing)
+          end
+        end
+      ))
+      expect(checker.problems.map(&:message)).to be_empty
+    end
+
+    it 'ignores undefined resolution failures' do
+      checker = type_checker(%(
+        class Foo
+          # @generic T
+          # @param klass [Class<undefined>>]
+          # @return [Set<generic<T>>]
+          def pins_by_class klass; [].to_set; end
+        end
+        class Bar
+          # @return [Enumerable<Integer>]
+          def block_pins
+            foo = Foo.new
+            foo.pins_by_class(Integer)
+          end
+        end
+      ))
+      expect(checker.problems.map(&:message)).to be_empty
+    end
+
+    it 'ignores generic resolution failures from current Solargraph limitation' do
+      checker = type_checker(%(
+        class Foo
+          # @generic T
+          # @param klass [Class<generic<T>>]
+          # @return [Set<generic<T>>]
+          def pins_by_class klass; [].to_set; end
+        end
+        class Bar
+          # @return [Enumerable<Integer>]
+          def block_pins
+            foo = Foo.new
+            foo.pins_by_class(Integer)
+          end
+        end
+      ))
+      expect(checker.problems.map(&:message)).to be_empty
+    end
+
+    it 'ignores generic resolution failures with only one arg' do
+      checker = type_checker(%(
+        # @generic T
+        # @param path [String]
+        # @param klass [Class<generic<T>>]
+        # @return [void]
+        def code_object_at path, klass = Integer
+        end
+      ))
+      expect(checker.problems.map(&:message)).to be_empty
+    end
+
+    it 'does not complain on select { is_a? } pattern' do
+      checker = type_checker(%(
+        # @param arr [Enumerable<Object>}
+        # @return [Enumerable<Integer>]
+        def downcast_arr(arr)
+          arr.select { |pin| pin.is_a?(Integer) }
+        end
+      ))
+      expect(checker.problems.map(&:message)).to be_empty
+    end
+
+    it 'does not complain on adding nil to types via return value' do
+      checker = type_checker(%(
+        # @param bar [Integer]
+        # @return [Integer, nil]
+        def foo(bar)
+          bar
+        end
+      ))
+      expect(checker.problems.map(&:message)).to be_empty
+    end
+
+    it 'does not complain on adding nil to types via select' do
+      checker = type_checker(%(
+        # @return [Float, nil]}
+        def bar; rand; end
+
+        # @param arr [Enumerable<Object>}
+        # @return [Integer, nil]
+        def downcast_arr(arr)
+          # @type [Object, nil]
+          foo = arr.select { |pin| pin.is_a?(Integer) && bar }.last
+          foo
+        end
+      ))
+      expect(checker.problems.map(&:message)).to be_empty
+    end
+
     it 'inherits param tags from superclass methods' do
       checker = type_checker(%(
         class Foo
@@ -152,5 +400,19 @@ def meth arg
       ))
       expect(checker.problems).to be_empty
     end
+
+    it 'understands Open3 methods' do
+      checker = type_checker(%(
+        require 'open3'
+
+        # @return [void]
+        def run_command
+          # @type [Hash{String => String}]
+          foo = {'foo' => 'bar'}
+          Open3.capture2e(foo, 'ls', chdir: '/tmp')
+        end
+      ))
+      expect(checker.problems.map(&:message)).to be_empty
+    end
   end
 end
diff --git a/spec/type_checker/levels/typed_spec.rb b/spec/type_checker/levels/typed_spec.rb
index b10bbd42c..e07aba2d3 100644
--- a/spec/type_checker/levels/typed_spec.rb
+++ b/spec/type_checker/levels/typed_spec.rb
@@ -1,6 +1,6 @@
 describe Solargraph::TypeChecker do
-  context 'typed level' do
-    def type_checker(code)
+  context 'when checking at typed level' do
+    def type_checker code
       Solargraph::TypeChecker.load_string(code, 'test.rb', :typed)
     end
 
@@ -38,6 +38,19 @@ def bar
       expect(checker.problems.first.message).to include('does not match')
     end
 
+    it 'reports mismatched key and subtypes' do
+      checker = type_checker(%(
+        # @return [Hash{String => String}]
+        def foo
+          # @type h [Hash{Integer => String}]
+          h = {}
+          h
+        end
+      ))
+      expect(checker.problems).to be_one
+      expect(checker.problems.first.message).to include('does not match')
+    end
+
     it 'reports mismatched inherited return tags' do
       checker = type_checker(%(
         class Sup
@@ -189,6 +202,31 @@ def foo
       expect(checker.problems).to be_empty
     end
 
+    it 'validates default values of parameters' do
+      checker = type_checker(%(
+        # @param bar [String]
+        def foo(bar = 123); end
+        ))
+      expect(checker.problems.map(&:message))
+        .to eq(['Declared type String does not match inferred type 123 for variable bar'])
+    end
+
+    it 'validates string default values of parameters' do
+      checker = type_checker(%(
+        # @param bar [String]
+        def foo(bar = 'foo'); end
+        ))
+      expect(checker.problems.map(&:message)).to be_empty
+    end
+
+    it 'validates symbol default values of parameters' do
+      checker = type_checker(%(
+        # @param bar [Symbol]
+        def foo(bar = :baz); end
+        ))
+      expect(checker.problems.map(&:message)).to eq([])
+    end
+
     it 'validates subclass arguments of param types' do
       checker = type_checker(%(
         class Sup
diff --git a/spec/workspace/gemspecs_fetch_dependencies_spec.rb b/spec/workspace/gemspecs_fetch_dependencies_spec.rb
new file mode 100644
index 000000000..9a21f967c
--- /dev/null
+++ b/spec/workspace/gemspecs_fetch_dependencies_spec.rb
@@ -0,0 +1,85 @@
+# frozen_string_literal: true
+
+require 'fileutils'
+require 'tmpdir'
+require 'rubygems/commands/install_command'
+
+describe Solargraph::Workspace::Gemspecs, '#fetch_dependencies' do
+  subject(:deps) { gemspecs.fetch_dependencies(gemspec) }
+
+  let(:gemspecs) { described_class.new(dir_path) }
+  let(:dir_path) { Dir.pwd }
+
+  context 'when in our bundle' do
+    context 'with a Bundler::LazySpecification' do
+      let(:gemspec) do
+        Bundler::LazySpecification.new('solargraph', nil, nil)
+      end
+
+      it 'finds a known dependency' do
+        expect(deps.map(&:name)).to include('backport')
+      end
+    end
+
+    context 'with gem whose dependency does not exist in our bundle' do
+      let(:gemspec) do
+        instance_double(Gem::Specification,
+                        dependencies: [Gem::Dependency.new('activerecord')],
+                        development_dependencies: [],
+                        name: 'my_fake_gem',
+                        version: '123')
+      end
+      let(:gem_name) { 'my_fake_gem' }
+
+      it 'gives a useful message' do
+        output = capture_both { deps.map(&:name) }
+        expect(output).to include('Please install the gem activerecord')
+      end
+    end
+  end
+
+  context 'with external bundle' do
+    let(:dir_path) { File.realpath(Dir.mktmpdir).to_s }
+
+    let(:gemspec) do
+      Bundler::LazySpecification.new(gem_name, nil, nil)
+    end
+
+    before do
+      # write out Gemfile
+      File.write(File.join(dir_path, 'Gemfile'), <<~GEMFILE)
+        source 'https://rubygems.org'
+        gem '#{gem_name}'
+      GEMFILE
+
+      # run bundle install
+      output, status = Solargraph.with_clean_env do
+        Open3.capture2e('bundle install --verbose', chdir: dir_path)
+      end
+      raise "Failure installing bundle: #{output}" unless status.success?
+
+      # ensure Gemfile.lock exists
+      unless File.exist?(File.join(dir_path, 'Gemfile.lock'))
+        raise "Gemfile.lock not found after bundle install in #{dir_path}"
+      end
+    end
+
+    context 'with gem that exists in our bundle' do
+      let(:gem_name) { 'undercover' }
+
+      it 'finds dependencies' do
+        expect(deps.map(&:name)).to include('ast')
+      end
+    end
+
+    context 'with gem does not exist in our bundle' do
+      let(:gem_name) { 'activerecord' }
+
+      it 'gives a useful message' do
+        dep_names = nil
+        output = capture_both { dep_names = deps.map(&:name) }
+        expect(output).to include('Please install the gem activerecord')
+      end
+    end
+  end
+end
diff --git a/spec/workspace/gemspecs_find_gem_spec.rb b/spec/workspace/gemspecs_find_gem_spec.rb
new file mode 100644
index 000000000..35f5e7a15
--- /dev/null
+++ b/spec/workspace/gemspecs_find_gem_spec.rb
@@ -0,0 +1,100 @@
+# frozen_string_literal: true
+
+require 'fileutils'
+require 'tmpdir'
+require 'rubygems/commands/install_command'
+
+describe Solargraph::Workspace::Gemspecs, '#find_gem' do
+  subject(:gemspec) { gemspecs.find_gem(name, version, out: out) }
+
+  let(:gemspecs) { described_class.new(dir_path) }
+  let(:out) { StringIO.new }
+
+  context 'with local bundle' do
+    let(:dir_path) { File.realpath(Dir.pwd) }
+
+    context 'with solargraph from bundle' do
+      let(:name) { 'solargraph' }
+      let(:version) { nil }
+
+      it 'returns the gem' do
+        expect(gemspec.name).to eq(name)
+      end
+    end
+
+    context 'with random from core' do
+      let(:name) { 'random' }
+      let(:version) { nil }
+
+      it 'returns no gemspec' do
+        expect(gemspec).to be_nil
+      end
+
+      it 'does not complain' do
+        expect(out.string).to be_empty
+      end
+    end
+
+    context 'with ripper from core' do
+      let(:name) { 'ripper' }
+      let(:version) { nil }
+
+      it 'returns no gemspec' do
+        expect(gemspec).to be_nil
+      end
+    end
+
+    context 'with base64 from stdlib' do
+      let(:name) { 'base64' }
+      let(:version) { nil }
+
+      it 'returns a gemspec' do
+        expect(gemspec).not_to be_nil
+      end
+    end
+
+    context 'with gem not in bundle' do
+      let(:name) { 'checkoff' }
+      let(:version) { nil }
+
+      it 'returns no gemspec' do
+        expect(gemspec).to be_nil
+      end
+
+      it 'complains' do
+        gemspec
+
+        expect(out.string).to include('install the gem checkoff ')
+      end
+    end
+
+    context 'with gem not in bundle but no logger' do
+      let(:name) { 'checkoff' }
+      let(:version) { nil }
+      let(:out) { nil }
+
+      it 'returns no gemspec' do
+        expect(gemspec).to be_nil
+      end
+
+      it 'does not fail' do
+        expect { gemspec }.not_to raise_error
+      end
+    end
+
+    context 'with gem not in bundle with version' do
+      let(:name) { 'checkoff' }
+      let(:version) { '1.0.0' }
+
+      it 'returns no gemspec' do
+        expect(gemspec).to be_nil
+      end
+
+      it 'complains' do
+        gemspec
+
+        expect(out.string).to include('install the gem checkoff:1.0.0')
+      end
+    end
+  end
+end
diff --git a/spec/workspace/gemspecs_resolve_require_spec.rb b/spec/workspace/gemspecs_resolve_require_spec.rb
new file mode 100644
index 000000000..f62ece83b
--- /dev/null
+++ b/spec/workspace/gemspecs_resolve_require_spec.rb
@@ -0,0 +1,291 @@
+# frozen_string_literal: true
+
+require 'fileutils'
+require 'tmpdir'
+require 'rubygems/commands/install_command'
+
+describe Solargraph::Workspace::Gemspecs, '#resolve_require' do
+  subject(:specs) { gemspecs.resolve_require(require) }
+
+  let(:gemspecs) { described_class.new(dir_path) }
+
+  def find_or_install gem_name, version
+    Gem::Specification.find_by_name(gem_name, version)
+  rescue Gem::LoadError
+    install_gem(gem_name, version)
+  end
+
+  def add_bundle
+    # write out Gemfile
+    File.write(File.join(dir_path, 'Gemfile'), <<~GEMFILE)
+      source 'https://rubygems.org'
+      gem 'backport'
+    GEMFILE
+    # run bundle install
+    output, status = Solargraph.with_clean_env do
+      Open3.capture2e('bundle install --verbose', chdir: dir_path)
+    end
+    raise "Failure installing bundle: #{output}" unless status.success?
+    # ensure Gemfile.lock exists
+    return if File.exist?(File.join(dir_path, 'Gemfile.lock'))
+    raise "Gemfile.lock not found after bundle install in #{dir_path}"
+  end
+
+  def install_gem gem_name, version
+    Bundler.with_unbundled_env do
+      cmd = Gem::Commands::InstallCommand.new
+      cmd.handle_options [gem_name, '-v', version]
+      cmd.execute
+    rescue Gem::SystemExitException => e
+      raise unless e.exit_code == 0
+    end
+  end
+
+  context 'with local bundle' do
+    let(:dir_path) { File.realpath(Dir.pwd) }
+
+    context 'with a known gem' do
+      let(:require) { 'solargraph' }
+
+      it 'returns a single spec' do
+        expect(specs.size).to eq(1)
+      end
+
+      it 'resolves to the right known gem' do
+        expect(specs.map(&:name)).to eq(['solargraph'])
+      end
+    end
+
+    context 'with an unknown type from Bundler / RubyGems' do
+      let(:require) { 'solargraph' }
+      let(:specish_objects) { [double] }
+
+      before do
+        lockfile = instance_double(Pathname)
+        locked_gems = instance_double(Bundler::LockfileParser, specs: specish_objects)
+
+        definition = instance_double(Bundler::Definition,
+                                     locked_gems: locked_gems,
+                                     lockfile: lockfile)
+        allow(Bundler).to receive(:definition).and_return(definition)
+        allow(lockfile).to receive(:to_s).and_return(dir_path)
+      end
+
+      it 'returns a single spec' do
+        expect(specs.size).to eq(1)
+      end
+
+      it 'resolves to the right known gem' do
+        expect(specs.map(&:name)).to eq(['solargraph'])
+      end
+    end
+
+    def configure_bundler_spec stub_value
+      platform = Gem::Platform::RUBY
+      bundler_stub_spec = Bundler::StubSpecification.new('solargraph', '123', platform, spec_fetcher)
+      specish_objects = [bundler_stub_spec]
+      lockfile = instance_double(Pathname)
+      locked_gems = instance_double(Bundler::LockfileParser, specs: specish_objects)
+      definition = instance_double(Bundler::Definition,
+                                   locked_gems: locked_gems,
+                                   lockfile: lockfile)
+      # specish_objects = Bundler.definition.locked_gems.specs
+      allow(Bundler).to receive(:definition).and_return(definition)
+      allow(lockfile).to receive(:to_s).and_return(dir_path)
+      allow(bundler_stub_spec).to receive(:respond_to?).with(:name).and_return(true)
+      allow(bundler_stub_spec).to receive(:respond_to?).with(:version).and_return(true)
+      allow(bundler_stub_spec).to receive(:respond_to?).with(:gem_dir).and_return(false)
+      allow(bundler_stub_spec).to receive(:respond_to?).with(:materialize_for_installation).and_return(false)
+      allow(bundler_stub_spec).to receive_messages(name: 'solargraph', stub: stub_value)
+    end
+
+    context 'with a Bundler::StubSpecification from Bundler / RubyGems' do
+      # this can happen from local gems, which is hard to test
+      # organically
+
+      let(:require) { 'solargraph' }
+      let(:spec_fetcher) { instance_double(Gem::SpecFetcher) }
+
+      before do
+        platform = Gem::Platform::RUBY
+        real_spec = instance_double(Gem::Specification)
+        allow(real_spec).to receive(:name).and_return('solargraph')
+        gem_stub_spec = Gem::StubSpecification.new('solargraph', '123', platform, spec_fetcher)
+        configure_bundler_spec(gem_stub_spec)
+        allow(gem_stub_spec).to receive_messages(name: 'solargraph', version: '123', spec: real_spec)
+      end
+
+      it 'returns a single spec' do
+        expect(specs.size).to eq(1)
+      end
+
+      it 'resolves to the right known gem' do
+        expect(specs.map(&:name)).to eq(['solargraph'])
+      end
+    end
+
+    context 'with a Bundler::StubSpecification that resolves straight to Gem::Specification' do
+      # have seen different behavior with different versions of rubygems/bundler
+
+      let(:require) { 'solargraph' }
+      let(:spec_fetcher) { instance_double(Gem::SpecFetcher) }
+      let(:real_spec) { Gem::Specification.new('solargraph', '123') }
+
+      before do
+        configure_bundler_spec(real_spec)
+      end
+
+      it 'returns a single spec' do
+        expect(specs.size).to eq(1)
+      end
+
+      it 'resolves to the right known gem' do
+        expect(specs.map(&:name)).to eq(['solargraph'])
+      end
+    end
+
+    context 'with a less usual require mapping' do
+      let(:require) { 'diff/lcs' }
+
+      it 'returns a single spec' do
+        expect(specs.size).to eq(1)
+      end
+
+      it 'resolves to the right known gem' do
+        expect(specs.map(&:name)).to eq(['diff-lcs'])
+      end
+    end
+
+    context 'with Bundler.require' do
+      let(:require) { 'bundler/require' }
+
+      it 'returns the gemspec gem' do
+        expect(specs.map(&:name)).to include('solargraph')
+      end
+    end
+  end
+
+  context 'with nil as directory' do
+    let(:dir_path) { nil }
+
+    context 'with simple require' do
+      let(:require) { 'solargraph' }
+
+      it 'finds solargraph' do
+        expect(specs.map(&:name)).to eq(['solargraph'])
+      end
+    end
+
+    context 'with Bundler.require' do
+      let(:require) { 'bundler/require' }
+
+      it 'finds nothing' do
+        expect(specs).to be_empty
+      end
+    end
+  end
+
+  context 'with external bundle' do
+    let(:dir_path) { File.realpath(Dir.mktmpdir).to_s }
+
+    context 'with no actual bundle' do
+      let(:require) { 'bundler/require' }
+
+      it 'raises' do
+        expect { specs }.to raise_error(Solargraph::BundleNotFoundError)
+      end
+    end
+
+    context 'with Gemfile and Bundler.require' do
+      before { add_bundle }
+
+      let(:require) { 'bundler/require' }
+
+      it 'does not raise' do
+        expect { specs }.not_to raise_error
+      end
+
+      it 'returns gems' do
+        expect(specs.map(&:name)).to include('backport')
+      end
+    end
+
+    context 'with Gemfile but an unknown gem' do
+      before { add_bundle }
+
+      let(:require) { 'unknown_gemlaksdflkdf' }
+
+      it 'returns nil' do
+        expect(specs).to be_nil
+      end
+    end
+
+    context 'with a Gemfile and a gem preference' do
+      # find_or_install helper doesn't seem to work on older versions
+      if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('3.1.0')
+        before do
+          add_bundle
+          find_or_install('backport', '1.0.0')
+          Gem::Specification.find_by_name('backport', '= 1.0.0')
+        end
+
+        let(:preferences) do
+          [
+            Gem::Specification.new.tap do |spec|
+              spec.name = 'backport'
+              spec.version = '1.0.0'
+            end
+          ]
+        end
+
+        it 'returns the preferred gemspec' do
+          gemspecs = described_class.new(dir_path, preferences: preferences)
+          specs = gemspecs.resolve_require('backport')
+          backport = specs.find { |spec| spec.name == 'backport' }
+
+          expect(backport.version.to_s).to eq('1.0.0')
+        end
+
+        context 'with a gem preference that does not exist' do
+          let(:preferences) do
+            [
+              Gem::Specification.new.tap do |spec|
+                spec.name = 'backport'
+                spec.version = '99.0.0'
+              end
+            ]
+          end
+
+          it 'returns the gemspec we do have' do
+            gemspecs = described_class.new(dir_path, preferences: preferences)
+            specs = gemspecs.resolve_require('backport')
+            backport = specs.find { |spec| spec.name == 'backport' }
+
+            expect(backport.version.to_s).to eq('1.2.0')
+          end
+        end
+
+        context 'with a gem preference already set to the version we use' do
+          let(:version) { Gem::Specification.find_by_name('backport').version.to_s }
+
+          let(:preferences) do
+            [
+              Gem::Specification.new.tap do |spec|
+                spec.name = 'backport'
+                spec.version = version
+              end
+            ]
+          end
+
+          it 'returns the gemspec we do have' do
+            gemspecs = described_class.new(dir_path, preferences: preferences)
+            specs = gemspecs.resolve_require('backport')
+            backport = specs.find { |spec| spec.name == 'backport' }
+
+            expect(backport.version.to_s).to eq(version)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/workspace/require_paths_spec.rb b/spec/workspace/require_paths_spec.rb
new file mode 100644
index 000000000..eb95d0c5b
--- /dev/null
+++ b/spec/workspace/require_paths_spec.rb
@@ -0,0 +1,87 @@
+# frozen_string_literal: true
+
+require 'fileutils'
+require 'tmpdir'
+
+describe Solargraph::Workspace::RequirePaths do
+  subject(:paths) { described_class.new(dir_path, config).generate }
+
+  let(:config) { Solargraph::Workspace::Config.new(dir_path) }
+
+  context 'with no config' do
+    let(:dir_path) { Dir.pwd }
+    let(:config) { nil }
+
+    it 'includes the lib directory' do
+      expect(paths).to include(File.join(dir_path, 'lib'))
+    end
+  end
+
+  context 'with config and no gemspec' do
+    let(:dir_path) { File.realpath(Dir.pwd) }
+
+    let(:config) { instance_double(Solargraph::Workspace::Config, require_paths: [], allow?: true) }
+
+    it 'includes the lib directory' do
+      expect(paths).to include(File.join(dir_path, 'lib'))
+    end
+  end
+
+  context 'with current bundle' do
+    let(:dir_path) { Dir.pwd }
+
+    it 'includes the lib directory' do
+      expect(paths).to include(File.join(dir_path, 'lib'))
+    end
+
+    it 'queried via Open3.capture3' do
+      allow(Open3).to receive(:capture3).and_call_original
+
+      paths
+
+      expect(Open3).to have_received(:capture3)
+    end
+  end
+
+  context 'with an invalid gemspec file' do
+    let(:dir_path) { File.realpath(Dir.mktmpdir) }
+    let(:gemspec_file) { File.join(dir_path, 'invalid.gemspec') }
+
+    before do
+      File.write(gemspec_file, 'bogus')
+    end
+
+    it 'includes the lib directory' do
+      expect(paths).to include(File.join(dir_path, 'lib'))
+    end
+
+    it 'does not raise an error' do
+      expect { paths }.not_to raise_error
+    end
+  end
+
+  context 'with a valid gemspec file that outputs to stdout' do
+    let(:dir_path) { File.realpath(Dir.mktmpdir) }
+    let(:gemspec_file) { File.join(dir_path, 'invalid.gemspec') }
+
+    before do
+      File.write(gemspec_file, "print '{'; Gem::Specification.new")
+    end
+
+    it 'includes the lib directory' do
+      expect(paths).to include(File.join(dir_path, 'lib'))
+    end
+
+    it 'does not raise an error' do
+      expect { paths }.not_to raise_error
+    end
+  end
+
+  context 'with no gemspec file' do
+    let(:dir_path) { File.realpath(Dir.mktmpdir) }
+
+    it 'includes the lib directory' do
+      expect(paths).to include(File.join(dir_path, 'lib'))
+    end
+  end
+end
diff --git a/spec/workspace_spec.rb b/spec/workspace_spec.rb
index 572c3e131..74d232a31 100644
--- a/spec/workspace_spec.rb
+++ b/spec/workspace_spec.rb
@@ -68,13 +68,6 @@
     }.not_to raise_error
   end
 
-  it "detects gemspecs in workspaces" do
-    gemspec_file = File.join(dir_path, 'test.gemspec')
-    File.write(gemspec_file, '')
-    expect(workspace.gemspec?).to be(true)
-    expect(workspace.gemspecs).to eq([gemspec_file])
-  end
-
   it "generates default require path" do
     expect(workspace.require_paths).to eq([File.join(dir_path, 'lib')])
   end
@@ -124,19 +117,52 @@
 
   it "uses configured require paths" do
     workspace = Solargraph::Workspace.new('spec/fixtures/workspace')
-    expect(workspace.require_paths).to eq(['spec/fixtures/workspace/lib', 'spec/fixtures/workspace/ext'])
-  end
-
-  it 'ignores gemspecs in excluded directories' do
-    # vendor/**/* is excluded by default
-    workspace = Solargraph::Workspace.new('spec/fixtures/vendored')
-    expect(workspace.gemspecs).to be_empty
+    expect(workspace.require_paths).to eq([File.absolute_path('spec/fixtures/workspace/lib'),
+                                           File.absolute_path('spec/fixtures/workspace/ext')])
   end
 
   it 'rescues errors loading files into sources' do
-    config = double(:Config, directory: './path', calculated: ['./path/does_not_exist.rb'], max_files: 5000, require_paths: [], plugins: [])
+    config = double(:Config, directory: './path', calculated: ['./path/does_not_exist.rb'], max_files: 5000,
+                             require_paths: [], plugins: [])
     expect {
       Solargraph::Workspace.new('./path', config)
     }.not_to raise_error
   end
+
+  describe '#cache_all_for_workspace!' do
+    let(:pin_cache) { instance_double(Solargraph::PinCache) }
+    let(:gemspecs) { instance_double(Solargraph::Workspace::Gemspecs) }
+
+    before do
+      allow(Solargraph::Workspace::Gemspecs).to receive(:new).and_return(gemspecs)
+      allow(Solargraph::PinCache).to receive(:cache_core)
+      allow(Solargraph::PinCache).to receive(:possible_stdlibs)
+      allow(Solargraph::PinCache).to receive(:new).and_return(pin_cache)
+      allow(pin_cache).to receive(:cache_gem)
+      allow(pin_cache).to receive(:cache_all_stdlibs)
+    end
+
+    it 'caches core pins' do
+      allow(Solargraph::PinCache).to receive(:core?).and_return(false)
+      allow(gemspecs).to receive(:all_gemspecs_from_bundle).and_return([])
+      allow(pin_cache).to receive(:possible_stdlibs).and_return([])
+
+      workspace.cache_all_for_workspace!(nil, rebuild: false)
+
+      expect(Solargraph::PinCache).to have_received(:cache_core).with(out: nil)
+    end
+
+    it 'caches gems' do
+      gemspec = instance_double(Gem::Specification, name: 'test_gem', version: '1.0.0')
+      allow(Solargraph::PinCache).to receive(:core?).and_return(true)
+      allow(gemspecs).to receive(:all_gemspecs_from_bundle).and_return([gemspec])
+      allow(pin_cache).to receive(:cached?).with(gemspec).and_return(false)
+      allow(pin_cache).to receive(:possible_stdlibs).and_return([])
+
+      workspace.cache_all_for_workspace!(nil, rebuild: false)
+
+      expect(pin_cache).to have_received(:cache_gem)
+        .with(gemspec: gemspec, rebuild: false, out: nil)
+    end
+  end
 end
diff --git a/spec/yard_map/mapper_spec.rb b/spec/yard_map/mapper_spec.rb
index 6b00e5c33..450b459e4 100644
--- a/spec/yard_map/mapper_spec.rb
+++ b/spec/yard_map/mapper_spec.rb
@@ -1,4 +1,14 @@
 describe Solargraph::YardMap::Mapper do
+  before :all do # rubocop:disable RSpec/BeforeAfterAll
+    @api_map = Solargraph::ApiMap.load('.')
+  end
+
+  def pins_with require
+    doc_map = Solargraph::DocMap.new([require], @api_map.workspace, out: nil) # rubocop:disable RSpec/InstanceVariable
+    doc_map.cache_doc_map_gems!(nil)
+    doc_map.pins
+  end
+
   it 'converts nil docstrings to empty strings' do
     dir = File.absolute_path(File.join('spec', 'fixtures', 'yard_map'))
     Dir.chdir dir do
@@ -14,50 +24,33 @@
 
   it 'marks explicit methods' do
     # Using rspec-expectations because it's a known dependency
-    rspec = Gem::Specification.find_by_name('rspec-expectations')
-    Solargraph::Yardoc.cache([], rspec)
-    Solargraph::Yardoc.load!(rspec)
-    pins = Solargraph::YardMap::Mapper.new(YARD::Registry.all).map
-    pin = pins.find { |pin| pin.path == 'RSpec::Matchers#be_truthy' }
+    pin = pins_with('rspec-expectations').find { |pin| pin.path == 'RSpec::Matchers#be_truthy' }
+    expect(pin).not_to be_nil
     expect(pin.explicit?).to be(true)
   end
 
   it 'marks correct return type from Logger.new' do
     # Using logger because it's a known dependency
-    logger = Gem::Specification.find_by_name('logger')
-    Solargraph::Yardoc.cache([], logger)
-    registry = Solargraph::Yardoc.load!(logger)
-    pins = Solargraph::YardMap::Mapper.new(registry).map
-    pins = pins.select { |pin| pin.path == 'Logger.new' }
+    pins = pins_with('logger').select { |pin| pin.path == 'Logger.new' }
     expect(pins.map(&:return_type).uniq.map(&:to_s)).to eq(['self'])
   end
 
   it 'marks correct return type from RuboCop::Options.new' do
     # Using rubocop because it's a known dependency
-    rubocop = Gem::Specification.find_by_name('rubocop')
-    Solargraph::Yardoc.cache([], rubocop)
-    Solargraph::Yardoc.load!(rubocop)
-    pins = Solargraph::YardMap::Mapper.new(YARD::Registry.all).map
-    pins = pins.select { |pin| pin.path == 'RuboCop::Options.new' }
+    pins = pins_with('rubocop').select { |pin| pin.path == 'RuboCop::Options.new' }
     expect(pins.map(&:return_type).uniq.map(&:to_s)).to eq(['self'])
     expect(pins.flat_map(&:signatures).map(&:return_type).uniq.map(&:to_s)).to eq(['self'])
   end
 
   it 'marks non-explicit methods' do
     # Using rspec-expectations because it's a known dependency
-    rspec = Gem::Specification.find_by_name('rspec-expectations')
-    Solargraph::Yardoc.load!(rspec)
-    pins = Solargraph::YardMap::Mapper.new(YARD::Registry.all).map
-    pin = pins.find { |pin| pin.path == 'RSpec::Matchers#expect' }
+    pin = pins_with('rspec-expectations').find { |pin| pin.path == 'RSpec::Matchers#expect' }
     expect(pin.explicit?).to be(false)
   end
 
   it 'adds superclass references' do
     # Asssuming the yard gem exists because it's a known dependency
-    gemspec = Gem::Specification.find_by_name('yard')
-    Solargraph::Yardoc.cache([], gemspec)
-    pins = Solargraph::YardMap::Mapper.new(Solargraph::Yardoc.load!(gemspec)).map
-    pin = pins.find do |pin|
+    pin = pins_with('yard').find do |pin|
       pin.is_a?(Solargraph::Pin::Reference::Superclass) && pin.name == 'YARD::CodeObjects::NamespaceObject'
     end
     expect(pin.closure.path).to eq('YARD::CodeObjects::ClassObject')
@@ -65,10 +58,7 @@
 
   it 'adds include references' do
     # Asssuming the ast gem exists because it's a known dependency
-    gemspec = Gem::Specification.find_by_name('ast')
-    Solargraph::Yardoc.cache([], gemspec)
-    pins = Solargraph::YardMap::Mapper.new(Solargraph::Yardoc.load!(gemspec)).map
-    inc= pins.find do |pin|
+    inc = pins_with('ast').find do |pin|
       pin.is_a?(Solargraph::Pin::Reference::Include) && pin.name == 'AST::Processor::Mixin' && pin.closure.path == 'AST::Processor'
     end
     expect(inc).to be_a(Solargraph::Pin::Reference::Include)
@@ -76,10 +66,7 @@
 
   it 'adds extend references' do
     # Asssuming the yard gem exists because it's a known dependency
-    gemspec = Gem::Specification.find_by_name('yard')
-    Solargraph::Yardoc.cache([], gemspec)
-    pins = Solargraph::YardMap::Mapper.new(Solargraph::Yardoc.load!(gemspec)).map
-    ext = pins.find do |pin|
+    ext = pins_with('yard').find do |pin|
       pin.is_a?(Solargraph::Pin::Reference::Extend) && pin.name == 'Enumerable' && pin.closure.path == 'YARD::Registry'
     end
     expect(ext).to be_a(Solargraph::Pin::Reference::Extend)
diff --git a/spec/yardoc_spec.rb b/spec/yardoc_spec.rb
new file mode 100644
index 000000000..e2fa5b89b
--- /dev/null
+++ b/spec/yardoc_spec.rb
@@ -0,0 +1,85 @@
+# frozen_string_literal: true
+
+require 'tmpdir'
+require 'open3'
+
+describe Solargraph::Yardoc do
+  around do |testobj|
+    @tmpdir = Dir.mktmpdir
+
+    testobj.run
+  ensure
+    FileUtils.remove_entry(@tmpdir) # rubocop:disable RSpec/InstanceVariable
+  end
+
+  let(:gem_yardoc_path) do
+    File.join(@tmpdir, 'solargraph', 'yardoc', 'test_gem') # rubocop:disable RSpec/InstanceVariable
+  end
+
+  before do
+    FileUtils.mkdir_p(gem_yardoc_path)
+  end
+
+  describe '#processing?' do
+    it 'returns true if the yardoc is being processed' do
+      FileUtils.touch(File.join(gem_yardoc_path, 'processing'))
+      expect(described_class.processing?(gem_yardoc_path)).to be(true)
+    end
+
+    it 'returns false if the yardoc is not being processed' do
+      expect(described_class.processing?(gem_yardoc_path)).to be(false)
+    end
+  end
+
+  describe '#load!' do
+    it 'does not blow up when called on empty directory' do
+      expect { described_class.load!(gem_yardoc_path) }.not_to raise_error
+    end
+  end
+
+  describe '#build_docs' do
+    let(:workspace) { Solargraph::Workspace.new(Dir.pwd) }
+    let(:gemspec) { workspace.find_gem('rubocop') }
+    let(:output) { '' }
+
+    before do
+      allow(Solargraph.logger).to receive(:warn)
+      allow(Solargraph.logger).to receive(:info)
+    end
+
+    it 'builds docs for a gem' do
+      described_class.build_docs(gem_yardoc_path, [], gemspec)
+      expect(File.exist?(File.join(gem_yardoc_path, 'complete'))).to be true
+    end
+
+    it 'bails quietly if directory given does not exist' do
+      allow(File).to receive(:exist?).and_return(false)
+
+      expect do
+        described_class.build_docs(gem_yardoc_path, [], gemspec)
+      end.not_to raise_error
+    end
+
+    it 'is idempotent' do
+      described_class.build_docs(gem_yardoc_path, [], gemspec)
+      described_class.build_docs(gem_yardoc_path, [], gemspec) # second time
+      expect(File.exist?(File.join(gem_yardoc_path, 'complete'))).to be true
+    end
+
+    context 'with an error from yard' do
+      before do
+        allow(Open3).to receive(:capture2e).and_return([output, result])
+      end
+
+      let(:result) { instance_double(Process::Status) }
+
+      it 'does not raise on error from yard' do
+        allow(result).to receive(:success?).and_return(false)
+
+        expect do
+          described_class.build_docs(gem_yardoc_path, [], gemspec)
+        end.not_to raise_error
+      end
+    end
+  end
+end