diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index a6f0d6dd2166a..fe844bbc66c04 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -2969,7 +2969,7 @@ namespace ts {
 
 
         function resolveExternalModuleName(location: Node, moduleReferenceExpression: Expression, ignoreErrors?: boolean): Symbol | undefined {
-            return resolveExternalModuleNameWorker(location, moduleReferenceExpression, ignoreErrors ? undefined : Diagnostics.Cannot_find_module_0);
+            return resolveExternalModuleNameWorker(location, moduleReferenceExpression, ignoreErrors ? undefined : Diagnostics.Cannot_find_module_0_or_its_corresponding_type_declarations);
         }
 
         function resolveExternalModuleNameWorker(location: Node, moduleReferenceExpression: Expression, moduleNotFoundError: DiagnosticMessage | undefined, isForAugmentation = false): Symbol | undefined {
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index b4b968301010a..66a61b065364e 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -1205,7 +1205,7 @@
         "category": "Error",
         "code": 2306
     },
-    "Cannot find module '{0}'.": {
+    "Cannot find module '{0}' or its corresponding type declarations.": {
         "category": "Error",
         "code": 2307
     },
diff --git a/src/services/codefixes/fixCannotFindModule.ts b/src/services/codefixes/fixCannotFindModule.ts
index 77393f0072ccb..a5d44c887b9a2 100644
--- a/src/services/codefixes/fixCannotFindModule.ts
+++ b/src/services/codefixes/fixCannotFindModule.ts
@@ -3,7 +3,7 @@ namespace ts.codefix {
     const fixName = "fixCannotFindModule";
     const fixIdInstallTypesPackage = "installTypesPackage";
 
-    const errorCodeCannotFindModule = Diagnostics.Cannot_find_module_0.code;
+    const errorCodeCannotFindModule = Diagnostics.Cannot_find_module_0_or_its_corresponding_type_declarations.code;
     const errorCodes = [
         errorCodeCannotFindModule,
         Diagnostics.Could_not_find_a_declaration_file_for_module_0_1_implicitly_has_an_any_type.code,
diff --git a/src/testRunner/unittests/tscWatch/helpers.ts b/src/testRunner/unittests/tscWatch/helpers.ts
index 5492b5cbfe63b..061fed7cb0af1 100644
--- a/src/testRunner/unittests/tscWatch/helpers.ts
+++ b/src/testRunner/unittests/tscWatch/helpers.ts
@@ -267,7 +267,7 @@ namespace ts.tscWatch {
 
     export function getDiagnosticModuleNotFoundOfFile(program: Program, file: File, moduleName: string) {
         const quotedModuleName = `"${moduleName}"`;
-        return getDiagnosticOfFileFromProgram(program, file.path, file.content.indexOf(quotedModuleName), quotedModuleName.length, Diagnostics.Cannot_find_module_0, moduleName);
+        return getDiagnosticOfFileFromProgram(program, file.path, file.content.indexOf(quotedModuleName), quotedModuleName.length, Diagnostics.Cannot_find_module_0_or_its_corresponding_type_declarations, moduleName);
     }
 
     export type TscWatchCompileChange = (
diff --git a/src/testRunner/unittests/tsserver/cachingFileSystemInformation.ts b/src/testRunner/unittests/tsserver/cachingFileSystemInformation.ts
index 5e6dc224cfcac..601e2fa345151 100644
--- a/src/testRunner/unittests/tsserver/cachingFileSystemInformation.ts
+++ b/src/testRunner/unittests/tsserver/cachingFileSystemInformation.ts
@@ -240,8 +240,8 @@ namespace ts.projectSystem {
             let diags = project.getLanguageService().getSemanticDiagnostics(root.path);
             assert.equal(diags.length, 1);
             const diag = diags[0];
-            assert.equal(diag.code, Diagnostics.Cannot_find_module_0.code);
-            assert.equal(flattenDiagnosticMessageText(diag.messageText, "\n"), "Cannot find module 'bar'.");
+            assert.equal(diag.code, Diagnostics.Cannot_find_module_0_or_its_corresponding_type_declarations.code);
+            assert.equal(flattenDiagnosticMessageText(diag.messageText, "\n"), "Cannot find module 'bar' or its corresponding type declarations.");
             callsTrackingHost.verifyCalledOn(CalledMapsWithSingleArg.fileExists, imported.path);
 
 
@@ -474,8 +474,8 @@ namespace ts.projectSystem {
 
                 const project = service.configuredProjects.get(tsconfig.path)!;
                 checkProjectActualFiles(project, files.map(f => f.path));
-                assert.deepEqual(project.getLanguageService().getSemanticDiagnostics(file1.path).map(diag => diag.messageText), ["Cannot find module 'debug'."]);
-                assert.deepEqual(project.getLanguageService().getSemanticDiagnostics(file2.path).map(diag => diag.messageText), ["Cannot find module 'debug'."]);
+                assert.deepEqual(project.getLanguageService().getSemanticDiagnostics(file1.path).map(diag => diag.messageText), ["Cannot find module 'debug' or its corresponding type declarations."]);
+                assert.deepEqual(project.getLanguageService().getSemanticDiagnostics(file2.path).map(diag => diag.messageText), ["Cannot find module 'debug' or its corresponding type declarations."]);
 
                 const debugTypesFile: File = {
                     path: `${projectLocation}/node_modules/debug/index.d.ts`,
@@ -682,7 +682,7 @@ namespace ts.projectSystem {
 
             const project = service.configuredProjects.get(tsconfig.path)!;
             checkProjectActualFiles(project, files.map(f => f.path));
-            assert.deepEqual(project.getLanguageService().getSemanticDiagnostics(app.path).map(diag => diag.messageText), ["Cannot find module 'debug'."]);
+            assert.deepEqual(project.getLanguageService().getSemanticDiagnostics(app.path).map(diag => diag.messageText), ["Cannot find module 'debug' or its corresponding type declarations."]);
 
             const debugTypesFile: File = {
                 path: `${projectLocation}/node_modules/@types/debug/index.d.ts`,
diff --git a/src/testRunner/unittests/tsserver/projectErrors.ts b/src/testRunner/unittests/tsserver/projectErrors.ts
index 2d8822493b03d..53b86448dae39 100644
--- a/src/testRunner/unittests/tsserver/projectErrors.ts
+++ b/src/testRunner/unittests/tsserver/projectErrors.ts
@@ -959,7 +959,7 @@ console.log(blabla);`
                 createDiagnostic(
                     span.start,
                     span.end,
-                    Diagnostics.Cannot_find_module_0,
+                    Diagnostics.Cannot_find_module_0_or_its_corresponding_type_declarations,
                     ["@angular/core"]
                 )
             ];
diff --git a/src/testRunner/unittests/tsserver/resolutionCache.ts b/src/testRunner/unittests/tsserver/resolutionCache.ts
index c1f4c755a3a59..d89a739c8d1ca 100644
--- a/src/testRunner/unittests/tsserver/resolutionCache.ts
+++ b/src/testRunner/unittests/tsserver/resolutionCache.ts
@@ -111,7 +111,7 @@ namespace ts.projectSystem {
             );
             let diags = session.executeCommand(getErrRequest).response as server.protocol.Diagnostic[];
             verifyDiagnostics(diags, [
-                { diagnosticMessage: Diagnostics.Cannot_find_module_0, errorTextArguments: ["./moduleFile"] }
+                { diagnosticMessage: Diagnostics.Cannot_find_module_0_or_its_corresponding_type_declarations, errorTextArguments: ["./moduleFile"] }
             ]);
 
             host.reloadFS([file1, moduleFile]);
@@ -158,7 +158,7 @@ namespace ts.projectSystem {
                     file: file1,
                     syntax: [],
                     semantic: [
-                        createDiagnostic({ line: 1, offset: startOffset }, { line: 1, offset: startOffset + '"pad"'.length }, Diagnostics.Cannot_find_module_0, ["pad"])
+                        createDiagnostic({ line: 1, offset: startOffset }, { line: 1, offset: startOffset + '"pad"'.length }, Diagnostics.Cannot_find_module_0_or_its_corresponding_type_declarations, ["pad"])
                     ],
                     suggestion: []
                 }]
@@ -342,7 +342,7 @@ namespace ts.projectSystem {
             host.runQueuedTimeoutCallbacks();
             diags = session.executeCommand(getErrRequest).response as server.protocol.Diagnostic[];
             verifyDiagnostics(diags, [
-                { diagnosticMessage: Diagnostics.Cannot_find_module_0, errorTextArguments: ["./moduleFile"] }
+                { diagnosticMessage: Diagnostics.Cannot_find_module_0_or_its_corresponding_type_declarations, errorTextArguments: ["./moduleFile"] }
             ]);
             assert.equal(diags.length, 1);
 
@@ -393,7 +393,7 @@ namespace ts.projectSystem {
             host.runQueuedTimeoutCallbacks();
             diags = session.executeCommand(getErrRequest).response as server.protocol.Diagnostic[];
             verifyDiagnostics(diags, [
-                { diagnosticMessage: Diagnostics.Cannot_find_module_0, errorTextArguments: ["./moduleFile"] }
+                { diagnosticMessage: Diagnostics.Cannot_find_module_0_or_its_corresponding_type_declarations, errorTextArguments: ["./moduleFile"] }
             ]);
 
             moduleFile.path = moduleFileOldPath;
diff --git a/src/testRunner/unittests/tsserver/symLinks.ts b/src/testRunner/unittests/tsserver/symLinks.ts
index 4576dc90c0792..8d22b240419a9 100644
--- a/src/testRunner/unittests/tsserver/symLinks.ts
+++ b/src/testRunner/unittests/tsserver/symLinks.ts
@@ -212,7 +212,7 @@ new C();`
                         verifyWatchedFilesAndDirectories(session.testhost, filesInProjectWithUnresolvedModule, watchedDirectoriesWithUnresolvedModule, nonRecursiveWatchedDirectories);
                         const startOffset = recognizersDateTimeSrcFile.content.indexOf('"') + 1;
                         verifyErrors(session, [
-                            createDiagnostic({ line: 1, offset: startOffset }, { line: 1, offset: startOffset + moduleNameInFile.length }, Diagnostics.Cannot_find_module_0, [moduleName])
+                            createDiagnostic({ line: 1, offset: startOffset }, { line: 1, offset: startOffset + moduleNameInFile.length }, Diagnostics.Cannot_find_module_0_or_its_corresponding_type_declarations, [moduleName])
                         ]);
                     }
 
diff --git a/tests/baselines/reference/aliasesInSystemModule1.errors.txt b/tests/baselines/reference/aliasesInSystemModule1.errors.txt
index d84223cc8a3ee..0d04ec6203d31 100644
--- a/tests/baselines/reference/aliasesInSystemModule1.errors.txt
+++ b/tests/baselines/reference/aliasesInSystemModule1.errors.txt
@@ -1,10 +1,10 @@
-tests/cases/compiler/aliasesInSystemModule1.ts(1,24): error TS2307: Cannot find module 'foo'.
+tests/cases/compiler/aliasesInSystemModule1.ts(1,24): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/aliasesInSystemModule1.ts (1 errors) ====
     import alias = require('foo');
                            ~~~~~
-!!! error TS2307: Cannot find module 'foo'.
+!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
     import cls = alias.Class;
     export import cls2 = alias.Class;
     
diff --git a/tests/baselines/reference/aliasesInSystemModule2.errors.txt b/tests/baselines/reference/aliasesInSystemModule2.errors.txt
index a1456b04cd824..d1ba8a1df831e 100644
--- a/tests/baselines/reference/aliasesInSystemModule2.errors.txt
+++ b/tests/baselines/reference/aliasesInSystemModule2.errors.txt
@@ -1,10 +1,10 @@
-tests/cases/compiler/aliasesInSystemModule2.ts(1,21): error TS2307: Cannot find module 'foo'.
+tests/cases/compiler/aliasesInSystemModule2.ts(1,21): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/aliasesInSystemModule2.ts (1 errors) ====
     import {alias} from "foo";
                         ~~~~~
-!!! error TS2307: Cannot find module 'foo'.
+!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
     import cls = alias.Class;
     export import cls2 = alias.Class;
     
diff --git a/tests/baselines/reference/ambientExternalModuleInAnotherExternalModule.errors.txt b/tests/baselines/reference/ambientExternalModuleInAnotherExternalModule.errors.txt
index 0757ba10e2e23..bd0137ffa34fe 100644
--- a/tests/baselines/reference/ambientExternalModuleInAnotherExternalModule.errors.txt
+++ b/tests/baselines/reference/ambientExternalModuleInAnotherExternalModule.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/compiler/ambientExternalModuleInAnotherExternalModule.ts(4,16): error TS2664: Invalid module name in augmentation, module 'ext' cannot be found.
-tests/cases/compiler/ambientExternalModuleInAnotherExternalModule.ts(9,22): error TS2307: Cannot find module 'ext'.
+tests/cases/compiler/ambientExternalModuleInAnotherExternalModule.ts(9,22): error TS2307: Cannot find module 'ext' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/ambientExternalModuleInAnotherExternalModule.ts (2 errors) ====
@@ -15,5 +15,5 @@ tests/cases/compiler/ambientExternalModuleInAnotherExternalModule.ts(9,22): erro
     // Cannot resolve this ext module reference
     import ext = require("ext");
                          ~~~~~
-!!! error TS2307: Cannot find module 'ext'.
+!!! error TS2307: Cannot find module 'ext' or its corresponding type declarations.
     var x = ext;
\ No newline at end of file
diff --git a/tests/baselines/reference/ambientExternalModuleWithRelativeExternalImportDeclaration.errors.txt b/tests/baselines/reference/ambientExternalModuleWithRelativeExternalImportDeclaration.errors.txt
index b7ccdc8df92ea..304081ff97fed 100644
--- a/tests/baselines/reference/ambientExternalModuleWithRelativeExternalImportDeclaration.errors.txt
+++ b/tests/baselines/reference/ambientExternalModuleWithRelativeExternalImportDeclaration.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/compiler/ambientExternalModuleWithRelativeExternalImportDeclaration.ts(2,5): error TS2439: Import or export declaration in an ambient module declaration cannot reference module through relative module name.
-tests/cases/compiler/ambientExternalModuleWithRelativeExternalImportDeclaration.ts(2,25): error TS2307: Cannot find module './SubModule'.
+tests/cases/compiler/ambientExternalModuleWithRelativeExternalImportDeclaration.ts(2,25): error TS2307: Cannot find module './SubModule' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/ambientExternalModuleWithRelativeExternalImportDeclaration.ts (2 errors) ====
@@ -8,7 +8,7 @@ tests/cases/compiler/ambientExternalModuleWithRelativeExternalImportDeclaration.
         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2439: Import or export declaration in an ambient module declaration cannot reference module through relative module name.
                             ~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module './SubModule'.
+!!! error TS2307: Cannot find module './SubModule' or its corresponding type declarations.
         class SubModule {
             public static StaticVar: number;
             public InstanceVar: number;
diff --git a/tests/baselines/reference/amdDependencyComment1.errors.txt b/tests/baselines/reference/amdDependencyComment1.errors.txt
index f3b5a5c06ccde..9806527857445 100644
--- a/tests/baselines/reference/amdDependencyComment1.errors.txt
+++ b/tests/baselines/reference/amdDependencyComment1.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/amdDependencyComment1.ts(3,21): error TS2307: Cannot find module 'm2'.
+tests/cases/compiler/amdDependencyComment1.ts(3,21): error TS2307: Cannot find module 'm2' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/amdDependencyComment1.ts (1 errors) ====
@@ -6,5 +6,5 @@ tests/cases/compiler/amdDependencyComment1.ts(3,21): error TS2307: Cannot find m
     
     import m1 = require("m2")
                         ~~~~
-!!! error TS2307: Cannot find module 'm2'.
+!!! error TS2307: Cannot find module 'm2' or its corresponding type declarations.
     m1.f();
\ No newline at end of file
diff --git a/tests/baselines/reference/amdDependencyComment2.errors.txt b/tests/baselines/reference/amdDependencyComment2.errors.txt
index e7d81514b906a..5f194cc081dfe 100644
--- a/tests/baselines/reference/amdDependencyComment2.errors.txt
+++ b/tests/baselines/reference/amdDependencyComment2.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/amdDependencyComment2.ts(3,21): error TS2307: Cannot find module 'm2'.
+tests/cases/compiler/amdDependencyComment2.ts(3,21): error TS2307: Cannot find module 'm2' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/amdDependencyComment2.ts (1 errors) ====
@@ -6,5 +6,5 @@ tests/cases/compiler/amdDependencyComment2.ts(3,21): error TS2307: Cannot find m
     
     import m1 = require("m2")
                         ~~~~
-!!! error TS2307: Cannot find module 'm2'.
+!!! error TS2307: Cannot find module 'm2' or its corresponding type declarations.
     m1.f();
\ No newline at end of file
diff --git a/tests/baselines/reference/amdDependencyCommentName1.errors.txt b/tests/baselines/reference/amdDependencyCommentName1.errors.txt
index f9e29ffe4c9ca..c5a8b31c814b4 100644
--- a/tests/baselines/reference/amdDependencyCommentName1.errors.txt
+++ b/tests/baselines/reference/amdDependencyCommentName1.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/amdDependencyCommentName1.ts(3,21): error TS2307: Cannot find module 'm2'.
+tests/cases/compiler/amdDependencyCommentName1.ts(3,21): error TS2307: Cannot find module 'm2' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/amdDependencyCommentName1.ts (1 errors) ====
@@ -6,5 +6,5 @@ tests/cases/compiler/amdDependencyCommentName1.ts(3,21): error TS2307: Cannot fi
     
     import m1 = require("m2")
                         ~~~~
-!!! error TS2307: Cannot find module 'm2'.
+!!! error TS2307: Cannot find module 'm2' or its corresponding type declarations.
     m1.f();
\ No newline at end of file
diff --git a/tests/baselines/reference/amdDependencyCommentName2.errors.txt b/tests/baselines/reference/amdDependencyCommentName2.errors.txt
index de9350187eaf3..935e839abbb27 100644
--- a/tests/baselines/reference/amdDependencyCommentName2.errors.txt
+++ b/tests/baselines/reference/amdDependencyCommentName2.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/amdDependencyCommentName2.ts(3,21): error TS2307: Cannot find module 'm2'.
+tests/cases/compiler/amdDependencyCommentName2.ts(3,21): error TS2307: Cannot find module 'm2' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/amdDependencyCommentName2.ts (1 errors) ====
@@ -6,5 +6,5 @@ tests/cases/compiler/amdDependencyCommentName2.ts(3,21): error TS2307: Cannot fi
     
     import m1 = require("m2")
                         ~~~~
-!!! error TS2307: Cannot find module 'm2'.
+!!! error TS2307: Cannot find module 'm2' or its corresponding type declarations.
     m1.f();
\ No newline at end of file
diff --git a/tests/baselines/reference/amdDependencyCommentName3.errors.txt b/tests/baselines/reference/amdDependencyCommentName3.errors.txt
index 6c3f1583314af..1da4d3c358a49 100644
--- a/tests/baselines/reference/amdDependencyCommentName3.errors.txt
+++ b/tests/baselines/reference/amdDependencyCommentName3.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/amdDependencyCommentName3.ts(5,21): error TS2307: Cannot find module 'm2'.
+tests/cases/compiler/amdDependencyCommentName3.ts(5,21): error TS2307: Cannot find module 'm2' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/amdDependencyCommentName3.ts (1 errors) ====
@@ -8,5 +8,5 @@ tests/cases/compiler/amdDependencyCommentName3.ts(5,21): error TS2307: Cannot fi
     
     import m1 = require("m2")
                         ~~~~
-!!! error TS2307: Cannot find module 'm2'.
+!!! error TS2307: Cannot find module 'm2' or its corresponding type declarations.
     m1.f();
\ No newline at end of file
diff --git a/tests/baselines/reference/amdDependencyCommentName4.errors.txt b/tests/baselines/reference/amdDependencyCommentName4.errors.txt
index 8031a651d0a6d..fb666eb711943 100644
--- a/tests/baselines/reference/amdDependencyCommentName4.errors.txt
+++ b/tests/baselines/reference/amdDependencyCommentName4.errors.txt
@@ -1,7 +1,7 @@
-tests/cases/compiler/amdDependencyCommentName4.ts(8,21): error TS2307: Cannot find module 'aliasedModule1'.
-tests/cases/compiler/amdDependencyCommentName4.ts(11,26): error TS2307: Cannot find module 'aliasedModule2'.
-tests/cases/compiler/amdDependencyCommentName4.ts(14,15): error TS2307: Cannot find module 'aliasedModule3'.
-tests/cases/compiler/amdDependencyCommentName4.ts(17,21): error TS2307: Cannot find module 'aliasedModule4'.
+tests/cases/compiler/amdDependencyCommentName4.ts(8,21): error TS2307: Cannot find module 'aliasedModule1' or its corresponding type declarations.
+tests/cases/compiler/amdDependencyCommentName4.ts(11,26): error TS2307: Cannot find module 'aliasedModule2' or its corresponding type declarations.
+tests/cases/compiler/amdDependencyCommentName4.ts(14,15): error TS2307: Cannot find module 'aliasedModule3' or its corresponding type declarations.
+tests/cases/compiler/amdDependencyCommentName4.ts(17,21): error TS2307: Cannot find module 'aliasedModule4' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/amdDependencyCommentName4.ts (4 errors) ====
@@ -14,22 +14,22 @@ tests/cases/compiler/amdDependencyCommentName4.ts(17,21): error TS2307: Cannot f
     
     import r1 = require("aliasedModule1");
                         ~~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'aliasedModule1'.
+!!! error TS2307: Cannot find module 'aliasedModule1' or its corresponding type declarations.
     r1;
     
     import {p1, p2, p3} from "aliasedModule2";
                              ~~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'aliasedModule2'.
+!!! error TS2307: Cannot find module 'aliasedModule2' or its corresponding type declarations.
     p1;
     
     import d from "aliasedModule3";
                   ~~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'aliasedModule3'.
+!!! error TS2307: Cannot find module 'aliasedModule3' or its corresponding type declarations.
     d;
     
     import * as ns from "aliasedModule4";
                         ~~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'aliasedModule4'.
+!!! error TS2307: Cannot find module 'aliasedModule4' or its corresponding type declarations.
     ns;
     
     import "unaliasedModule2";
\ No newline at end of file
diff --git a/tests/baselines/reference/asyncAwaitIsolatedModules_es2017.errors.txt b/tests/baselines/reference/asyncAwaitIsolatedModules_es2017.errors.txt
index 95927c283aa4b..25392e59232af 100644
--- a/tests/baselines/reference/asyncAwaitIsolatedModules_es2017.errors.txt
+++ b/tests/baselines/reference/asyncAwaitIsolatedModules_es2017.errors.txt
@@ -1,10 +1,10 @@
-tests/cases/conformance/async/es2017/asyncAwaitIsolatedModules_es2017.ts(1,27): error TS2307: Cannot find module 'missing'.
+tests/cases/conformance/async/es2017/asyncAwaitIsolatedModules_es2017.ts(1,27): error TS2307: Cannot find module 'missing' or its corresponding type declarations.
 
 
 ==== tests/cases/conformance/async/es2017/asyncAwaitIsolatedModules_es2017.ts (1 errors) ====
     import { MyPromise } from "missing";
                               ~~~~~~~~~
-!!! error TS2307: Cannot find module 'missing'.
+!!! error TS2307: Cannot find module 'missing' or its corresponding type declarations.
     
     declare var p: Promise<number>;
     declare var mp: MyPromise<number>;
diff --git a/tests/baselines/reference/asyncAwaitIsolatedModules_es5.errors.txt b/tests/baselines/reference/asyncAwaitIsolatedModules_es5.errors.txt
index 7d46517ca159f..da84692b5326d 100644
--- a/tests/baselines/reference/asyncAwaitIsolatedModules_es5.errors.txt
+++ b/tests/baselines/reference/asyncAwaitIsolatedModules_es5.errors.txt
@@ -1,10 +1,10 @@
-tests/cases/conformance/async/es5/asyncAwaitIsolatedModules_es5.ts(1,27): error TS2307: Cannot find module 'missing'.
+tests/cases/conformance/async/es5/asyncAwaitIsolatedModules_es5.ts(1,27): error TS2307: Cannot find module 'missing' or its corresponding type declarations.
 
 
 ==== tests/cases/conformance/async/es5/asyncAwaitIsolatedModules_es5.ts (1 errors) ====
     import { MyPromise } from "missing";
                               ~~~~~~~~~
-!!! error TS2307: Cannot find module 'missing'.
+!!! error TS2307: Cannot find module 'missing' or its corresponding type declarations.
     
     declare var p: Promise<number>;
     declare var mp: MyPromise<number>;
diff --git a/tests/baselines/reference/asyncAwaitIsolatedModules_es6.errors.txt b/tests/baselines/reference/asyncAwaitIsolatedModules_es6.errors.txt
index 068fbb604e1e9..ddd91b09afbdc 100644
--- a/tests/baselines/reference/asyncAwaitIsolatedModules_es6.errors.txt
+++ b/tests/baselines/reference/asyncAwaitIsolatedModules_es6.errors.txt
@@ -1,10 +1,10 @@
-tests/cases/conformance/async/es6/asyncAwaitIsolatedModules_es6.ts(1,27): error TS2307: Cannot find module 'missing'.
+tests/cases/conformance/async/es6/asyncAwaitIsolatedModules_es6.ts(1,27): error TS2307: Cannot find module 'missing' or its corresponding type declarations.
 
 
 ==== tests/cases/conformance/async/es6/asyncAwaitIsolatedModules_es6.ts (1 errors) ====
     import { MyPromise } from "missing";
                               ~~~~~~~~~
-!!! error TS2307: Cannot find module 'missing'.
+!!! error TS2307: Cannot find module 'missing' or its corresponding type declarations.
     
     declare var p: Promise<number>;
     declare var mp: MyPromise<number>;
diff --git a/tests/baselines/reference/badExternalModuleReference.errors.txt b/tests/baselines/reference/badExternalModuleReference.errors.txt
index e5caaaf296fb4..1133400b65a97 100644
--- a/tests/baselines/reference/badExternalModuleReference.errors.txt
+++ b/tests/baselines/reference/badExternalModuleReference.errors.txt
@@ -1,10 +1,10 @@
-tests/cases/compiler/badExternalModuleReference.ts(1,21): error TS2307: Cannot find module 'garbage'.
+tests/cases/compiler/badExternalModuleReference.ts(1,21): error TS2307: Cannot find module 'garbage' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/badExternalModuleReference.ts (1 errors) ====
     import a1 = require("garbage");
                         ~~~~~~~~~
-!!! error TS2307: Cannot find module 'garbage'.
+!!! error TS2307: Cannot find module 'garbage' or its corresponding type declarations.
     export declare var a: {
         test1: a1.connectModule;
         (): a1.connectExport;
diff --git a/tests/baselines/reference/cachedModuleResolution6.errors.txt b/tests/baselines/reference/cachedModuleResolution6.errors.txt
index 7d79a200e11ed..e80de6969f6a4 100644
--- a/tests/baselines/reference/cachedModuleResolution6.errors.txt
+++ b/tests/baselines/reference/cachedModuleResolution6.errors.txt
@@ -1,13 +1,13 @@
-/a/b/c/d/e/app.ts(1,17): error TS2307: Cannot find module 'foo'.
-/a/b/c/lib.ts(1,17): error TS2307: Cannot find module 'foo'.
+/a/b/c/d/e/app.ts(1,17): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
+/a/b/c/lib.ts(1,17): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
 
 
 ==== /a/b/c/d/e/app.ts (1 errors) ====
     import {x} from "foo";
                     ~~~~~
-!!! error TS2307: Cannot find module 'foo'.
+!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
     
 ==== /a/b/c/lib.ts (1 errors) ====
     import {x} from "foo";
                     ~~~~~
-!!! error TS2307: Cannot find module 'foo'.
\ No newline at end of file
+!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
\ No newline at end of file
diff --git a/tests/baselines/reference/cachedModuleResolution7.errors.txt b/tests/baselines/reference/cachedModuleResolution7.errors.txt
index 9bc6e3f239cd7..8274accb5b883 100644
--- a/tests/baselines/reference/cachedModuleResolution7.errors.txt
+++ b/tests/baselines/reference/cachedModuleResolution7.errors.txt
@@ -1,14 +1,14 @@
-/a/b/c/d/e/app.ts(1,17): error TS2307: Cannot find module 'foo'.
-/a/b/c/lib.ts(1,17): error TS2307: Cannot find module 'foo'.
+/a/b/c/d/e/app.ts(1,17): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
+/a/b/c/lib.ts(1,17): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
 
 
 ==== /a/b/c/lib.ts (1 errors) ====
     import {x} from "foo";
                     ~~~~~
-!!! error TS2307: Cannot find module 'foo'.
+!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
     
 ==== /a/b/c/d/e/app.ts (1 errors) ====
     import {x} from "foo";
                     ~~~~~
-!!! error TS2307: Cannot find module 'foo'.
+!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/cachedModuleResolution8.errors.txt b/tests/baselines/reference/cachedModuleResolution8.errors.txt
index 7d79a200e11ed..e80de6969f6a4 100644
--- a/tests/baselines/reference/cachedModuleResolution8.errors.txt
+++ b/tests/baselines/reference/cachedModuleResolution8.errors.txt
@@ -1,13 +1,13 @@
-/a/b/c/d/e/app.ts(1,17): error TS2307: Cannot find module 'foo'.
-/a/b/c/lib.ts(1,17): error TS2307: Cannot find module 'foo'.
+/a/b/c/d/e/app.ts(1,17): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
+/a/b/c/lib.ts(1,17): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
 
 
 ==== /a/b/c/d/e/app.ts (1 errors) ====
     import {x} from "foo";
                     ~~~~~
-!!! error TS2307: Cannot find module 'foo'.
+!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
     
 ==== /a/b/c/lib.ts (1 errors) ====
     import {x} from "foo";
                     ~~~~~
-!!! error TS2307: Cannot find module 'foo'.
\ No newline at end of file
+!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
\ No newline at end of file
diff --git a/tests/baselines/reference/cachedModuleResolution9.errors.txt b/tests/baselines/reference/cachedModuleResolution9.errors.txt
index 482a34cb654f3..0dc795af6b3ba 100644
--- a/tests/baselines/reference/cachedModuleResolution9.errors.txt
+++ b/tests/baselines/reference/cachedModuleResolution9.errors.txt
@@ -1,15 +1,15 @@
-/a/b/c/d/e/app.ts(1,17): error TS2307: Cannot find module 'foo'.
-/a/b/c/lib.ts(1,17): error TS2307: Cannot find module 'foo'.
+/a/b/c/d/e/app.ts(1,17): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
+/a/b/c/lib.ts(1,17): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
 
 
 ==== /a/b/c/lib.ts (1 errors) ====
     import {x} from "foo";
                     ~~~~~
-!!! error TS2307: Cannot find module 'foo'.
+!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
     
     
 ==== /a/b/c/d/e/app.ts (1 errors) ====
     import {x} from "foo";
                     ~~~~~
-!!! error TS2307: Cannot find module 'foo'.
+!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/commentOnImportStatement1.errors.txt b/tests/baselines/reference/commentOnImportStatement1.errors.txt
index c6dcaf31c4f77..5fb5009fa23c7 100644
--- a/tests/baselines/reference/commentOnImportStatement1.errors.txt
+++ b/tests/baselines/reference/commentOnImportStatement1.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/commentOnImportStatement1.ts(3,22): error TS2307: Cannot find module './foo'.
+tests/cases/compiler/commentOnImportStatement1.ts(3,22): error TS2307: Cannot find module './foo' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/commentOnImportStatement1.ts (1 errors) ====
@@ -6,5 +6,5 @@ tests/cases/compiler/commentOnImportStatement1.ts(3,22): error TS2307: Cannot fi
     
     import foo = require('./foo');
                          ~~~~~~~
-!!! error TS2307: Cannot find module './foo'.
+!!! error TS2307: Cannot find module './foo' or its corresponding type declarations.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/commentOnImportStatement2.errors.txt b/tests/baselines/reference/commentOnImportStatement2.errors.txt
index 31f11a1c14830..15e1b29db4e63 100644
--- a/tests/baselines/reference/commentOnImportStatement2.errors.txt
+++ b/tests/baselines/reference/commentOnImportStatement2.errors.txt
@@ -1,8 +1,8 @@
-tests/cases/compiler/commentOnImportStatement2.ts(2,22): error TS2307: Cannot find module './foo'.
+tests/cases/compiler/commentOnImportStatement2.ts(2,22): error TS2307: Cannot find module './foo' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/commentOnImportStatement2.ts (1 errors) ====
     /* not copyright */
     import foo = require('./foo');
                          ~~~~~~~
-!!! error TS2307: Cannot find module './foo'.
\ No newline at end of file
+!!! error TS2307: Cannot find module './foo' or its corresponding type declarations.
\ No newline at end of file
diff --git a/tests/baselines/reference/commentOnImportStatement3.errors.txt b/tests/baselines/reference/commentOnImportStatement3.errors.txt
index ec47c42dc41b1..5a2a5323bf02b 100644
--- a/tests/baselines/reference/commentOnImportStatement3.errors.txt
+++ b/tests/baselines/reference/commentOnImportStatement3.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/commentOnImportStatement3.ts(4,22): error TS2307: Cannot find module './foo'.
+tests/cases/compiler/commentOnImportStatement3.ts(4,22): error TS2307: Cannot find module './foo' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/commentOnImportStatement3.ts (1 errors) ====
@@ -7,4 +7,4 @@ tests/cases/compiler/commentOnImportStatement3.ts(4,22): error TS2307: Cannot fi
     /* not copyright */
     import foo = require('./foo');
                          ~~~~~~~
-!!! error TS2307: Cannot find module './foo'.
\ No newline at end of file
+!!! error TS2307: Cannot find module './foo' or its corresponding type declarations.
\ No newline at end of file
diff --git a/tests/baselines/reference/copyrightWithNewLine1.errors.txt b/tests/baselines/reference/copyrightWithNewLine1.errors.txt
index 9f5932a2b2ec7..21c19c41741ed 100644
--- a/tests/baselines/reference/copyrightWithNewLine1.errors.txt
+++ b/tests/baselines/reference/copyrightWithNewLine1.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/copyrightWithNewLine1.ts(5,24): error TS2307: Cannot find module './greeter'.
+tests/cases/compiler/copyrightWithNewLine1.ts(5,24): error TS2307: Cannot find module './greeter' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/copyrightWithNewLine1.ts (1 errors) ====
@@ -8,7 +8,7 @@ tests/cases/compiler/copyrightWithNewLine1.ts(5,24): error TS2307: Cannot find m
     
     import model = require("./greeter")
                            ~~~~~~~~~~~
-!!! error TS2307: Cannot find module './greeter'.
+!!! error TS2307: Cannot find module './greeter' or its corresponding type declarations.
     var el = document.getElementById('content');
     var greeter = new model.Greeter(el);
     /** things */
diff --git a/tests/baselines/reference/copyrightWithoutNewLine1.errors.txt b/tests/baselines/reference/copyrightWithoutNewLine1.errors.txt
index 71194988ca235..51bc742228672 100644
--- a/tests/baselines/reference/copyrightWithoutNewLine1.errors.txt
+++ b/tests/baselines/reference/copyrightWithoutNewLine1.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/copyrightWithoutNewLine1.ts(4,24): error TS2307: Cannot find module './greeter'.
+tests/cases/compiler/copyrightWithoutNewLine1.ts(4,24): error TS2307: Cannot find module './greeter' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/copyrightWithoutNewLine1.ts (1 errors) ====
@@ -7,7 +7,7 @@ tests/cases/compiler/copyrightWithoutNewLine1.ts(4,24): error TS2307: Cannot fin
     ****************************/
     import model = require("./greeter")
                            ~~~~~~~~~~~
-!!! error TS2307: Cannot find module './greeter'.
+!!! error TS2307: Cannot find module './greeter' or its corresponding type declarations.
     var el = document.getElementById('content');
     var greeter = new model.Greeter(el);
     /** things */
diff --git a/tests/baselines/reference/deduplicateImportsInSystem.errors.txt b/tests/baselines/reference/deduplicateImportsInSystem.errors.txt
index 3ce3f88c81786..e77bd5cfaa033 100644
--- a/tests/baselines/reference/deduplicateImportsInSystem.errors.txt
+++ b/tests/baselines/reference/deduplicateImportsInSystem.errors.txt
@@ -1,29 +1,29 @@
-tests/cases/compiler/deduplicateImportsInSystem.ts(1,17): error TS2307: Cannot find module 'f1'.
-tests/cases/compiler/deduplicateImportsInSystem.ts(2,17): error TS2307: Cannot find module 'f2'.
-tests/cases/compiler/deduplicateImportsInSystem.ts(3,17): error TS2307: Cannot find module 'f3'.
-tests/cases/compiler/deduplicateImportsInSystem.ts(4,17): error TS2307: Cannot find module 'f2'.
-tests/cases/compiler/deduplicateImportsInSystem.ts(5,17): error TS2307: Cannot find module 'f2'.
-tests/cases/compiler/deduplicateImportsInSystem.ts(6,17): error TS2307: Cannot find module 'f1'.
+tests/cases/compiler/deduplicateImportsInSystem.ts(1,17): error TS2307: Cannot find module 'f1' or its corresponding type declarations.
+tests/cases/compiler/deduplicateImportsInSystem.ts(2,17): error TS2307: Cannot find module 'f2' or its corresponding type declarations.
+tests/cases/compiler/deduplicateImportsInSystem.ts(3,17): error TS2307: Cannot find module 'f3' or its corresponding type declarations.
+tests/cases/compiler/deduplicateImportsInSystem.ts(4,17): error TS2307: Cannot find module 'f2' or its corresponding type declarations.
+tests/cases/compiler/deduplicateImportsInSystem.ts(5,17): error TS2307: Cannot find module 'f2' or its corresponding type declarations.
+tests/cases/compiler/deduplicateImportsInSystem.ts(6,17): error TS2307: Cannot find module 'f1' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/deduplicateImportsInSystem.ts (6 errors) ====
     import {A} from "f1";
                     ~~~~
-!!! error TS2307: Cannot find module 'f1'.
+!!! error TS2307: Cannot find module 'f1' or its corresponding type declarations.
     import {B} from "f2";
                     ~~~~
-!!! error TS2307: Cannot find module 'f2'.
+!!! error TS2307: Cannot find module 'f2' or its corresponding type declarations.
     import {C} from "f3";
                     ~~~~
-!!! error TS2307: Cannot find module 'f3'.
+!!! error TS2307: Cannot find module 'f3' or its corresponding type declarations.
     import {D} from 'f2';
                     ~~~~
-!!! error TS2307: Cannot find module 'f2'.
+!!! error TS2307: Cannot find module 'f2' or its corresponding type declarations.
     import {E} from "f2";
                     ~~~~
-!!! error TS2307: Cannot find module 'f2'.
+!!! error TS2307: Cannot find module 'f2' or its corresponding type declarations.
     import {F} from 'f1';
                     ~~~~
-!!! error TS2307: Cannot find module 'f1'.
+!!! error TS2307: Cannot find module 'f1' or its corresponding type declarations.
     
     console.log(A + B + C + D + E + F)
\ No newline at end of file
diff --git a/tests/baselines/reference/defaultExportsCannotMerge01.errors.txt b/tests/baselines/reference/defaultExportsCannotMerge01.errors.txt
index 5c28d8ee14135..ab8bf95686e51 100644
--- a/tests/baselines/reference/defaultExportsCannotMerge01.errors.txt
+++ b/tests/baselines/reference/defaultExportsCannotMerge01.errors.txt
@@ -1,6 +1,6 @@
 tests/cases/conformance/es6/modules/m1.ts(1,25): error TS2652: Merged declaration 'Decl' cannot include a default export declaration. Consider adding a separate 'export default Decl' declaration instead.
 tests/cases/conformance/es6/modules/m1.ts(10,18): error TS2652: Merged declaration 'Decl' cannot include a default export declaration. Consider adding a separate 'export default Decl' declaration instead.
-tests/cases/conformance/es6/modules/m2.ts(1,20): error TS2307: Cannot find module 'm1'.
+tests/cases/conformance/es6/modules/m2.ts(1,20): error TS2307: Cannot find module 'm1' or its corresponding type declarations.
 
 
 ==== tests/cases/conformance/es6/modules/m1.ts (2 errors) ====
@@ -28,7 +28,7 @@ tests/cases/conformance/es6/modules/m2.ts(1,20): error TS2307: Cannot find modul
 ==== tests/cases/conformance/es6/modules/m2.ts (1 errors) ====
     import Entity from "m1"
                        ~~~~
-!!! error TS2307: Cannot find module 'm1'.
+!!! error TS2307: Cannot find module 'm1' or its corresponding type declarations.
     
     Entity();
     
diff --git a/tests/baselines/reference/defaultExportsCannotMerge02.errors.txt b/tests/baselines/reference/defaultExportsCannotMerge02.errors.txt
index 737a481487b96..084fb7c452b86 100644
--- a/tests/baselines/reference/defaultExportsCannotMerge02.errors.txt
+++ b/tests/baselines/reference/defaultExportsCannotMerge02.errors.txt
@@ -1,6 +1,6 @@
 tests/cases/conformance/es6/modules/m1.ts(1,22): error TS2652: Merged declaration 'Decl' cannot include a default export declaration. Consider adding a separate 'export default Decl' declaration instead.
 tests/cases/conformance/es6/modules/m1.ts(4,18): error TS2652: Merged declaration 'Decl' cannot include a default export declaration. Consider adding a separate 'export default Decl' declaration instead.
-tests/cases/conformance/es6/modules/m2.ts(1,20): error TS2307: Cannot find module 'm1'.
+tests/cases/conformance/es6/modules/m2.ts(1,20): error TS2307: Cannot find module 'm1' or its corresponding type declarations.
 
 
 ==== tests/cases/conformance/es6/modules/m1.ts (2 errors) ====
@@ -24,7 +24,7 @@ tests/cases/conformance/es6/modules/m2.ts(1,20): error TS2307: Cannot find modul
 ==== tests/cases/conformance/es6/modules/m2.ts (1 errors) ====
     import Entity from "m1"
                        ~~~~
-!!! error TS2307: Cannot find module 'm1'.
+!!! error TS2307: Cannot find module 'm1' or its corresponding type declarations.
     
     Entity();
     
diff --git a/tests/baselines/reference/defaultExportsCannotMerge03.errors.txt b/tests/baselines/reference/defaultExportsCannotMerge03.errors.txt
index 7452554fd352b..4560d83406197 100644
--- a/tests/baselines/reference/defaultExportsCannotMerge03.errors.txt
+++ b/tests/baselines/reference/defaultExportsCannotMerge03.errors.txt
@@ -1,6 +1,6 @@
 tests/cases/conformance/es6/modules/m1.ts(1,22): error TS2652: Merged declaration 'Decl' cannot include a default export declaration. Consider adding a separate 'export default Decl' declaration instead.
 tests/cases/conformance/es6/modules/m1.ts(4,11): error TS2652: Merged declaration 'Decl' cannot include a default export declaration. Consider adding a separate 'export default Decl' declaration instead.
-tests/cases/conformance/es6/modules/m2.ts(1,20): error TS2307: Cannot find module 'm1'.
+tests/cases/conformance/es6/modules/m2.ts(1,20): error TS2307: Cannot find module 'm1' or its corresponding type declarations.
 
 
 ==== tests/cases/conformance/es6/modules/m1.ts (2 errors) ====
@@ -24,7 +24,7 @@ tests/cases/conformance/es6/modules/m2.ts(1,20): error TS2307: Cannot find modul
 ==== tests/cases/conformance/es6/modules/m2.ts (1 errors) ====
     import Entity from "m1"
                        ~~~~
-!!! error TS2307: Cannot find module 'm1'.
+!!! error TS2307: Cannot find module 'm1' or its corresponding type declarations.
     
     Entity();
     
diff --git a/tests/baselines/reference/dynamicImportInDefaultExportExpression.errors.txt b/tests/baselines/reference/dynamicImportInDefaultExportExpression.errors.txt
index 8bf6704b74358..5c1b13a5d0199 100644
--- a/tests/baselines/reference/dynamicImportInDefaultExportExpression.errors.txt
+++ b/tests/baselines/reference/dynamicImportInDefaultExportExpression.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/dynamicImportInDefaultExportExpression.ts(3,23): error TS2307: Cannot find module './foo2'.
+tests/cases/compiler/dynamicImportInDefaultExportExpression.ts(3,23): error TS2307: Cannot find module './foo2' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/dynamicImportInDefaultExportExpression.ts (1 errors) ====
@@ -6,6 +6,6 @@ tests/cases/compiler/dynamicImportInDefaultExportExpression.ts(3,23): error TS23
         getInstance: function () {
             return import('./foo2');
                           ~~~~~~~~
-!!! error TS2307: Cannot find module './foo2'.
+!!! error TS2307: Cannot find module './foo2' or its corresponding type declarations.
         }
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/emptyModuleName.errors.txt b/tests/baselines/reference/emptyModuleName.errors.txt
index 16f04b247ea24..234115c02568b 100644
--- a/tests/baselines/reference/emptyModuleName.errors.txt
+++ b/tests/baselines/reference/emptyModuleName.errors.txt
@@ -1,9 +1,9 @@
-tests/cases/compiler/emptyModuleName.ts(1,20): error TS2307: Cannot find module ''.
+tests/cases/compiler/emptyModuleName.ts(1,20): error TS2307: Cannot find module '' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/emptyModuleName.ts (1 errors) ====
     import * as A from "";
                        ~~
-!!! error TS2307: Cannot find module ''.
+!!! error TS2307: Cannot find module '' or its corresponding type declarations.
     class B extends A {
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/es5ModuleInternalNamedImports.errors.txt b/tests/baselines/reference/es5ModuleInternalNamedImports.errors.txt
index be6bb246c9088..92124b17fae39 100644
--- a/tests/baselines/reference/es5ModuleInternalNamedImports.errors.txt
+++ b/tests/baselines/reference/es5ModuleInternalNamedImports.errors.txt
@@ -9,7 +9,7 @@ tests/cases/compiler/es5ModuleInternalNamedImports.ts(29,5): error TS1194: Expor
 tests/cases/compiler/es5ModuleInternalNamedImports.ts(30,25): error TS1147: Import declarations in a namespace cannot reference a module.
 tests/cases/compiler/es5ModuleInternalNamedImports.ts(31,20): error TS1147: Import declarations in a namespace cannot reference a module.
 tests/cases/compiler/es5ModuleInternalNamedImports.ts(32,32): error TS1147: Import declarations in a namespace cannot reference a module.
-tests/cases/compiler/es5ModuleInternalNamedImports.ts(34,16): error TS2307: Cannot find module 'M3'.
+tests/cases/compiler/es5ModuleInternalNamedImports.ts(34,16): error TS2307: Cannot find module 'M3' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/es5ModuleInternalNamedImports.ts (12 errors) ====
@@ -70,5 +70,5 @@ tests/cases/compiler/es5ModuleInternalNamedImports.ts(34,16): error TS2307: Cann
     }
     import M3 from "M3";
                    ~~~~
-!!! error TS2307: Cannot find module 'M3'.
+!!! error TS2307: Cannot find module 'M3' or its corresponding type declarations.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/es6ImportNamedImportIdentifiersParsing.errors.txt b/tests/baselines/reference/es6ImportNamedImportIdentifiersParsing.errors.txt
index 34a33ccab9708..2ea94f08a103f 100644
--- a/tests/baselines/reference/es6ImportNamedImportIdentifiersParsing.errors.txt
+++ b/tests/baselines/reference/es6ImportNamedImportIdentifiersParsing.errors.txt
@@ -1,16 +1,16 @@
 tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts(1,10): error TS2300: Duplicate identifier 'yield'.
-tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts(1,23): error TS2307: Cannot find module 'somemodule'.
+tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts(1,23): error TS2307: Cannot find module 'somemodule' or its corresponding type declarations.
 tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts(2,10): error TS1003: Identifier expected.
 tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts(2,10): error TS2300: Duplicate identifier 'default'.
-tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts(2,25): error TS2307: Cannot find module 'somemodule'.
+tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts(2,25): error TS2307: Cannot find module 'somemodule' or its corresponding type declarations.
 tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts(3,19): error TS1003: Identifier expected.
 tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts(3,19): error TS2300: Duplicate identifier 'default'.
-tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts(3,34): error TS2307: Cannot find module 'somemodule'.
+tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts(3,34): error TS2307: Cannot find module 'somemodule' or its corresponding type declarations.
 tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts(4,21): error TS2300: Duplicate identifier 'yield'.
-tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts(4,34): error TS2307: Cannot find module 'somemodule'.
+tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts(4,34): error TS2307: Cannot find module 'somemodule' or its corresponding type declarations.
 tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts(5,21): error TS1003: Identifier expected.
 tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts(5,21): error TS2300: Duplicate identifier 'default'.
-tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts(5,36): error TS2307: Cannot find module 'somemodule'.
+tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts(5,36): error TS2307: Cannot find module 'somemodule' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts (13 errors) ====
@@ -18,30 +18,30 @@ tests/cases/compiler/es6ImportNamedImportIdentifiersParsing.ts(5,36): error TS23
              ~~~~~
 !!! error TS2300: Duplicate identifier 'yield'.
                           ~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'somemodule'.
+!!! error TS2307: Cannot find module 'somemodule' or its corresponding type declarations.
     import { default } from "somemodule"; // Error - as this is keyword that is not allowed as identifier
              ~~~~~~~
 !!! error TS1003: Identifier expected.
              ~~~~~~~
 !!! error TS2300: Duplicate identifier 'default'.
                             ~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'somemodule'.
+!!! error TS2307: Cannot find module 'somemodule' or its corresponding type declarations.
     import { yield as default } from "somemodule"; // error to use default as binding name
                       ~~~~~~~
 !!! error TS1003: Identifier expected.
                       ~~~~~~~
 !!! error TS2300: Duplicate identifier 'default'.
                                      ~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'somemodule'.
+!!! error TS2307: Cannot find module 'somemodule' or its corresponding type declarations.
     import { default as yield } from "somemodule"; // no error 
                         ~~~~~
 !!! error TS2300: Duplicate identifier 'yield'.
                                      ~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'somemodule'.
+!!! error TS2307: Cannot find module 'somemodule' or its corresponding type declarations.
     import { default as default } from "somemodule"; // default as is ok, error of default binding name
                         ~~~~~~~
 !!! error TS1003: Identifier expected.
                         ~~~~~~~
 !!! error TS2300: Duplicate identifier 'default'.
                                        ~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'somemodule'.
\ No newline at end of file
+!!! error TS2307: Cannot find module 'somemodule' or its corresponding type declarations.
\ No newline at end of file
diff --git a/tests/baselines/reference/es6modulekindWithES5Target10.errors.txt b/tests/baselines/reference/es6modulekindWithES5Target10.errors.txt
index d4164e56491f0..fa234f98d868d 100644
--- a/tests/baselines/reference/es6modulekindWithES5Target10.errors.txt
+++ b/tests/baselines/reference/es6modulekindWithES5Target10.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/conformance/externalModules/es6/es6modulekindWithES5Target10.ts(1,1): error TS1202: Import assignment cannot be used when targeting ECMAScript modules. Consider using 'import * as ns from "mod"', 'import {a} from "mod"', 'import d from "mod"', or another module format instead.
-tests/cases/conformance/externalModules/es6/es6modulekindWithES5Target10.ts(1,20): error TS2307: Cannot find module 'mod'.
+tests/cases/conformance/externalModules/es6/es6modulekindWithES5Target10.ts(1,20): error TS2307: Cannot find module 'mod' or its corresponding type declarations.
 tests/cases/conformance/externalModules/es6/es6modulekindWithES5Target10.ts(6,1): error TS1203: Export assignment cannot be used when targeting ECMAScript modules. Consider using 'export default' or another module format instead.
 
 
@@ -8,7 +8,7 @@ tests/cases/conformance/externalModules/es6/es6modulekindWithES5Target10.ts(6,1)
     ~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS1202: Import assignment cannot be used when targeting ECMAScript modules. Consider using 'import * as ns from "mod"', 'import {a} from "mod"', 'import d from "mod"', or another module format instead.
                        ~~~~~
-!!! error TS2307: Cannot find module 'mod'.
+!!! error TS2307: Cannot find module 'mod' or its corresponding type declarations.
     
     
     namespace N {
diff --git a/tests/baselines/reference/es6modulekindWithES5Target9.errors.txt b/tests/baselines/reference/es6modulekindWithES5Target9.errors.txt
index 10351e925295c..7251d1d520384 100644
--- a/tests/baselines/reference/es6modulekindWithES5Target9.errors.txt
+++ b/tests/baselines/reference/es6modulekindWithES5Target9.errors.txt
@@ -1,22 +1,22 @@
-tests/cases/conformance/externalModules/es6/es6modulekindWithES5Target9.ts(1,15): error TS2307: Cannot find module 'mod'.
-tests/cases/conformance/externalModules/es6/es6modulekindWithES5Target9.ts(3,17): error TS2307: Cannot find module 'mod'.
-tests/cases/conformance/externalModules/es6/es6modulekindWithES5Target9.ts(5,20): error TS2307: Cannot find module 'mod'.
-tests/cases/conformance/externalModules/es6/es6modulekindWithES5Target9.ts(13,15): error TS2307: Cannot find module 'mod'.
-tests/cases/conformance/externalModules/es6/es6modulekindWithES5Target9.ts(15,17): error TS2307: Cannot find module 'mod'.
+tests/cases/conformance/externalModules/es6/es6modulekindWithES5Target9.ts(1,15): error TS2307: Cannot find module 'mod' or its corresponding type declarations.
+tests/cases/conformance/externalModules/es6/es6modulekindWithES5Target9.ts(3,17): error TS2307: Cannot find module 'mod' or its corresponding type declarations.
+tests/cases/conformance/externalModules/es6/es6modulekindWithES5Target9.ts(5,20): error TS2307: Cannot find module 'mod' or its corresponding type declarations.
+tests/cases/conformance/externalModules/es6/es6modulekindWithES5Target9.ts(13,15): error TS2307: Cannot find module 'mod' or its corresponding type declarations.
+tests/cases/conformance/externalModules/es6/es6modulekindWithES5Target9.ts(15,17): error TS2307: Cannot find module 'mod' or its corresponding type declarations.
 
 
 ==== tests/cases/conformance/externalModules/es6/es6modulekindWithES5Target9.ts (5 errors) ====
     import d from "mod";
                   ~~~~~
-!!! error TS2307: Cannot find module 'mod'.
+!!! error TS2307: Cannot find module 'mod' or its corresponding type declarations.
     
     import {a} from "mod";
                     ~~~~~
-!!! error TS2307: Cannot find module 'mod'.
+!!! error TS2307: Cannot find module 'mod' or its corresponding type declarations.
     
     import * as M from "mod";
                        ~~~~~
-!!! error TS2307: Cannot find module 'mod'.
+!!! error TS2307: Cannot find module 'mod' or its corresponding type declarations.
     
     export {a};
     
@@ -26,11 +26,11 @@ tests/cases/conformance/externalModules/es6/es6modulekindWithES5Target9.ts(15,17
     
     export * from "mod";
                   ~~~~~
-!!! error TS2307: Cannot find module 'mod'.
+!!! error TS2307: Cannot find module 'mod' or its corresponding type declarations.
     
     export {b} from "mod"
                     ~~~~~
-!!! error TS2307: Cannot find module 'mod'.
+!!! error TS2307: Cannot find module 'mod' or its corresponding type declarations.
     
     export default d;
     
\ No newline at end of file
diff --git a/tests/baselines/reference/esModuleInteropImportDefaultWhenAllNamedAreDefaultAlias.errors.txt b/tests/baselines/reference/esModuleInteropImportDefaultWhenAllNamedAreDefaultAlias.errors.txt
index a31b6647198c5..c74eafe4e35dd 100644
--- a/tests/baselines/reference/esModuleInteropImportDefaultWhenAllNamedAreDefaultAlias.errors.txt
+++ b/tests/baselines/reference/esModuleInteropImportDefaultWhenAllNamedAreDefaultAlias.errors.txt
@@ -1,9 +1,9 @@
-tests/cases/compiler/esModuleInteropImportDefaultWhenAllNamedAreDefaultAlias.ts(1,42): error TS2307: Cannot find module 'm'.
+tests/cases/compiler/esModuleInteropImportDefaultWhenAllNamedAreDefaultAlias.ts(1,42): error TS2307: Cannot find module 'm' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/esModuleInteropImportDefaultWhenAllNamedAreDefaultAlias.ts (1 errors) ====
     import {default as a, default as b} from "m";
                                              ~~~
-!!! error TS2307: Cannot find module 'm'.
+!!! error TS2307: Cannot find module 'm' or its corresponding type declarations.
     void a;
     void b;
\ No newline at end of file
diff --git a/tests/baselines/reference/esModuleInteropUsesExportStarWhenDefaultPlusNames.errors.txt b/tests/baselines/reference/esModuleInteropUsesExportStarWhenDefaultPlusNames.errors.txt
index 2634c6ea44161..dcfa66eed6f71 100644
--- a/tests/baselines/reference/esModuleInteropUsesExportStarWhenDefaultPlusNames.errors.txt
+++ b/tests/baselines/reference/esModuleInteropUsesExportStarWhenDefaultPlusNames.errors.txt
@@ -1,9 +1,9 @@
-tests/cases/compiler/esModuleInteropUsesExportStarWhenDefaultPlusNames.ts(1,28): error TS2307: Cannot find module './dep'.
+tests/cases/compiler/esModuleInteropUsesExportStarWhenDefaultPlusNames.ts(1,28): error TS2307: Cannot find module './dep' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/esModuleInteropUsesExportStarWhenDefaultPlusNames.ts (1 errors) ====
     import Deps, { var2 } from './dep';
                                ~~~~~~~
-!!! error TS2307: Cannot find module './dep'.
+!!! error TS2307: Cannot find module './dep' or its corresponding type declarations.
     void Deps;
     void var2;
\ No newline at end of file
diff --git a/tests/baselines/reference/esnextmodulekindWithES5Target10.errors.txt b/tests/baselines/reference/esnextmodulekindWithES5Target10.errors.txt
index 4793bc650addd..00445d9e1a2d1 100644
--- a/tests/baselines/reference/esnextmodulekindWithES5Target10.errors.txt
+++ b/tests/baselines/reference/esnextmodulekindWithES5Target10.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/conformance/externalModules/esnext/esnextmodulekindWithES5Target10.ts(1,1): error TS1202: Import assignment cannot be used when targeting ECMAScript modules. Consider using 'import * as ns from "mod"', 'import {a} from "mod"', 'import d from "mod"', or another module format instead.
-tests/cases/conformance/externalModules/esnext/esnextmodulekindWithES5Target10.ts(1,20): error TS2307: Cannot find module 'mod'.
+tests/cases/conformance/externalModules/esnext/esnextmodulekindWithES5Target10.ts(1,20): error TS2307: Cannot find module 'mod' or its corresponding type declarations.
 tests/cases/conformance/externalModules/esnext/esnextmodulekindWithES5Target10.ts(6,1): error TS1203: Export assignment cannot be used when targeting ECMAScript modules. Consider using 'export default' or another module format instead.
 
 
@@ -8,7 +8,7 @@ tests/cases/conformance/externalModules/esnext/esnextmodulekindWithES5Target10.t
     ~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS1202: Import assignment cannot be used when targeting ECMAScript modules. Consider using 'import * as ns from "mod"', 'import {a} from "mod"', 'import d from "mod"', or another module format instead.
                        ~~~~~
-!!! error TS2307: Cannot find module 'mod'.
+!!! error TS2307: Cannot find module 'mod' or its corresponding type declarations.
     
     
     namespace N {
diff --git a/tests/baselines/reference/esnextmodulekindWithES5Target9.errors.txt b/tests/baselines/reference/esnextmodulekindWithES5Target9.errors.txt
index cccb20f965930..476bad6c5d2f2 100644
--- a/tests/baselines/reference/esnextmodulekindWithES5Target9.errors.txt
+++ b/tests/baselines/reference/esnextmodulekindWithES5Target9.errors.txt
@@ -1,22 +1,22 @@
-tests/cases/conformance/externalModules/esnext/esnextmodulekindWithES5Target9.ts(1,15): error TS2307: Cannot find module 'mod'.
-tests/cases/conformance/externalModules/esnext/esnextmodulekindWithES5Target9.ts(3,17): error TS2307: Cannot find module 'mod'.
-tests/cases/conformance/externalModules/esnext/esnextmodulekindWithES5Target9.ts(5,20): error TS2307: Cannot find module 'mod'.
-tests/cases/conformance/externalModules/esnext/esnextmodulekindWithES5Target9.ts(13,15): error TS2307: Cannot find module 'mod'.
-tests/cases/conformance/externalModules/esnext/esnextmodulekindWithES5Target9.ts(15,17): error TS2307: Cannot find module 'mod'.
+tests/cases/conformance/externalModules/esnext/esnextmodulekindWithES5Target9.ts(1,15): error TS2307: Cannot find module 'mod' or its corresponding type declarations.
+tests/cases/conformance/externalModules/esnext/esnextmodulekindWithES5Target9.ts(3,17): error TS2307: Cannot find module 'mod' or its corresponding type declarations.
+tests/cases/conformance/externalModules/esnext/esnextmodulekindWithES5Target9.ts(5,20): error TS2307: Cannot find module 'mod' or its corresponding type declarations.
+tests/cases/conformance/externalModules/esnext/esnextmodulekindWithES5Target9.ts(13,15): error TS2307: Cannot find module 'mod' or its corresponding type declarations.
+tests/cases/conformance/externalModules/esnext/esnextmodulekindWithES5Target9.ts(15,17): error TS2307: Cannot find module 'mod' or its corresponding type declarations.
 
 
 ==== tests/cases/conformance/externalModules/esnext/esnextmodulekindWithES5Target9.ts (5 errors) ====
     import d from "mod";
                   ~~~~~
-!!! error TS2307: Cannot find module 'mod'.
+!!! error TS2307: Cannot find module 'mod' or its corresponding type declarations.
     
     import {a} from "mod";
                     ~~~~~
-!!! error TS2307: Cannot find module 'mod'.
+!!! error TS2307: Cannot find module 'mod' or its corresponding type declarations.
     
     import * as M from "mod";
                        ~~~~~
-!!! error TS2307: Cannot find module 'mod'.
+!!! error TS2307: Cannot find module 'mod' or its corresponding type declarations.
     
     export {a};
     
@@ -26,11 +26,11 @@ tests/cases/conformance/externalModules/esnext/esnextmodulekindWithES5Target9.ts
     
     export * from "mod";
                   ~~~~~
-!!! error TS2307: Cannot find module 'mod'.
+!!! error TS2307: Cannot find module 'mod' or its corresponding type declarations.
     
     export {b} from "mod"
                     ~~~~~
-!!! error TS2307: Cannot find module 'mod'.
+!!! error TS2307: Cannot find module 'mod' or its corresponding type declarations.
     
     export default d;
     
\ No newline at end of file
diff --git a/tests/baselines/reference/importCallExpressionGrammarError.errors.txt b/tests/baselines/reference/importCallExpressionGrammarError.errors.txt
index b39228f100d4b..bc90a5042ba7f 100644
--- a/tests/baselines/reference/importCallExpressionGrammarError.errors.txt
+++ b/tests/baselines/reference/importCallExpressionGrammarError.errors.txt
@@ -2,7 +2,7 @@ tests/cases/conformance/dynamicImport/importCallExpressionGrammarError.ts(5,8):
 tests/cases/conformance/dynamicImport/importCallExpressionGrammarError.ts(7,17): error TS1325: Specifier of dynamic import cannot be spread element.
 tests/cases/conformance/dynamicImport/importCallExpressionGrammarError.ts(8,12): error TS1324: Dynamic import must have one specifier as an argument.
 tests/cases/conformance/dynamicImport/importCallExpressionGrammarError.ts(9,12): error TS1324: Dynamic import must have one specifier as an argument.
-tests/cases/conformance/dynamicImport/importCallExpressionGrammarError.ts(9,19): error TS2307: Cannot find module 'pathToModule'.
+tests/cases/conformance/dynamicImport/importCallExpressionGrammarError.ts(9,19): error TS2307: Cannot find module 'pathToModule' or its corresponding type declarations.
 
 
 ==== tests/cases/conformance/dynamicImport/importCallExpressionGrammarError.ts (5 errors) ====
@@ -24,4 +24,4 @@ tests/cases/conformance/dynamicImport/importCallExpressionGrammarError.ts(9,19):
                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS1324: Dynamic import must have one specifier as an argument.
                       ~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'pathToModule'.
\ No newline at end of file
+!!! error TS2307: Cannot find module 'pathToModule' or its corresponding type declarations.
\ No newline at end of file
diff --git a/tests/baselines/reference/importDeclRefereingExternalModuleWithNoResolve.errors.txt b/tests/baselines/reference/importDeclRefereingExternalModuleWithNoResolve.errors.txt
index 4bfe02c0467c6..f5e7d238b6a53 100644
--- a/tests/baselines/reference/importDeclRefereingExternalModuleWithNoResolve.errors.txt
+++ b/tests/baselines/reference/importDeclRefereingExternalModuleWithNoResolve.errors.txt
@@ -1,17 +1,17 @@
-tests/cases/compiler/importDeclRefereingExternalModuleWithNoResolve.ts(1,20): error TS2307: Cannot find module 'externalModule'.
+tests/cases/compiler/importDeclRefereingExternalModuleWithNoResolve.ts(1,20): error TS2307: Cannot find module 'externalModule' or its corresponding type declarations.
 tests/cases/compiler/importDeclRefereingExternalModuleWithNoResolve.ts(2,16): error TS2664: Invalid module name in augmentation, module 'm1' cannot be found.
-tests/cases/compiler/importDeclRefereingExternalModuleWithNoResolve.ts(3,26): error TS2307: Cannot find module 'externalModule'.
+tests/cases/compiler/importDeclRefereingExternalModuleWithNoResolve.ts(3,26): error TS2307: Cannot find module 'externalModule' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/importDeclRefereingExternalModuleWithNoResolve.ts (3 errors) ====
     import b = require("externalModule");
                        ~~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'externalModule'.
+!!! error TS2307: Cannot find module 'externalModule' or its corresponding type declarations.
     declare module "m1" {
                    ~~~~
 !!! error TS2664: Invalid module name in augmentation, module 'm1' cannot be found.
         import im2 = require("externalModule");
                              ~~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'externalModule'.
+!!! error TS2307: Cannot find module 'externalModule' or its corresponding type declarations.
     }
     
\ No newline at end of file
diff --git a/tests/baselines/reference/importEmptyFromModuleNotExisted.errors.txt b/tests/baselines/reference/importEmptyFromModuleNotExisted.errors.txt
index 99ccd49c4895e..b41e4b55fbddc 100644
--- a/tests/baselines/reference/importEmptyFromModuleNotExisted.errors.txt
+++ b/tests/baselines/reference/importEmptyFromModuleNotExisted.errors.txt
@@ -1,8 +1,8 @@
-tests/cases/conformance/es6/modules/importEmptyFromModuleNotExisted.ts(1,16): error TS2307: Cannot find module 'module-not-existed'.
+tests/cases/conformance/es6/modules/importEmptyFromModuleNotExisted.ts(1,16): error TS2307: Cannot find module 'module-not-existed' or its corresponding type declarations.
 
 
 ==== tests/cases/conformance/es6/modules/importEmptyFromModuleNotExisted.ts (1 errors) ====
     import {} from 'module-not-existed'
                    ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'module-not-existed'.
+!!! error TS2307: Cannot find module 'module-not-existed' or its corresponding type declarations.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/importInsideModule.errors.txt b/tests/baselines/reference/importInsideModule.errors.txt
index fcf82bd24940f..f43d696989730 100644
--- a/tests/baselines/reference/importInsideModule.errors.txt
+++ b/tests/baselines/reference/importInsideModule.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/compiler/importInsideModule_file2.ts(2,26): error TS1147: Import declarations in a namespace cannot reference a module.
-tests/cases/compiler/importInsideModule_file2.ts(2,26): error TS2307: Cannot find module 'importInsideModule_file1'.
+tests/cases/compiler/importInsideModule_file2.ts(2,26): error TS2307: Cannot find module 'importInsideModule_file1' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/importInsideModule_file2.ts (2 errors) ====
@@ -8,7 +8,7 @@ tests/cases/compiler/importInsideModule_file2.ts(2,26): error TS2307: Cannot fin
                              ~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                              ~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'importInsideModule_file1'.
+!!! error TS2307: Cannot find module 'importInsideModule_file1' or its corresponding type declarations.
         var a = foo.x;
     }
 ==== tests/cases/compiler/importInsideModule_file1.ts (0 errors) ====
diff --git a/tests/baselines/reference/importNotElidedWhenNotFound.errors.txt b/tests/baselines/reference/importNotElidedWhenNotFound.errors.txt
index b8245c0081d24..7132c52f7851a 100644
--- a/tests/baselines/reference/importNotElidedWhenNotFound.errors.txt
+++ b/tests/baselines/reference/importNotElidedWhenNotFound.errors.txt
@@ -1,16 +1,16 @@
-tests/cases/compiler/importNotElidedWhenNotFound.ts(1,15): error TS2307: Cannot find module 'file'.
-tests/cases/compiler/importNotElidedWhenNotFound.ts(2,15): error TS2307: Cannot find module 'other_file'.
-tests/cases/compiler/importNotElidedWhenNotFound.ts(10,16): error TS2307: Cannot find module 'file2'.
-tests/cases/compiler/importNotElidedWhenNotFound.ts(11,16): error TS2307: Cannot find module 'file3'.
+tests/cases/compiler/importNotElidedWhenNotFound.ts(1,15): error TS2307: Cannot find module 'file' or its corresponding type declarations.
+tests/cases/compiler/importNotElidedWhenNotFound.ts(2,15): error TS2307: Cannot find module 'other_file' or its corresponding type declarations.
+tests/cases/compiler/importNotElidedWhenNotFound.ts(10,16): error TS2307: Cannot find module 'file2' or its corresponding type declarations.
+tests/cases/compiler/importNotElidedWhenNotFound.ts(11,16): error TS2307: Cannot find module 'file3' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/importNotElidedWhenNotFound.ts (4 errors) ====
     import X from 'file';
                   ~~~~~~
-!!! error TS2307: Cannot find module 'file'.
+!!! error TS2307: Cannot find module 'file' or its corresponding type declarations.
     import Z from 'other_file';
                   ~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'other_file'.
+!!! error TS2307: Cannot find module 'other_file' or its corresponding type declarations.
     
     class Y extends Z {
       constructor() {
@@ -20,10 +20,10 @@ tests/cases/compiler/importNotElidedWhenNotFound.ts(11,16): error TS2307: Cannot
     
     import X2 from 'file2';
                    ~~~~~~~
-!!! error TS2307: Cannot find module 'file2'.
+!!! error TS2307: Cannot find module 'file2' or its corresponding type declarations.
     import X3 from 'file3';
                    ~~~~~~~
-!!! error TS2307: Cannot find module 'file3'.
+!!! error TS2307: Cannot find module 'file3' or its corresponding type declarations.
     class Q extends Z {
       constructor() {
         super(X2, X3);
diff --git a/tests/baselines/reference/importTypeAmbientMissing.errors.txt b/tests/baselines/reference/importTypeAmbientMissing.errors.txt
index 89beac01c37c0..25c8ffc8762c7 100644
--- a/tests/baselines/reference/importTypeAmbientMissing.errors.txt
+++ b/tests/baselines/reference/importTypeAmbientMissing.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/conformance/types/import/importTypeAmbientMissing.ts(8,17): error TS2307: Cannot find module 'fo'.
+tests/cases/conformance/types/import/importTypeAmbientMissing.ts(8,17): error TS2307: Cannot find module 'fo' or its corresponding type declarations.
 
 
 ==== tests/cases/conformance/types/import/importTypeAmbientMissing.ts (1 errors) ====
@@ -11,6 +11,6 @@ tests/cases/conformance/types/import/importTypeAmbientMissing.ts(8,17): error TS
     }
     const x: import("fo") = { x: 0, y: 0 }; // typo, error
                     ~~~~
-!!! error TS2307: Cannot find module 'fo'.
+!!! error TS2307: Cannot find module 'fo' or its corresponding type declarations.
     
     
\ No newline at end of file
diff --git a/tests/baselines/reference/importTypeLocalMissing.errors.txt b/tests/baselines/reference/importTypeLocalMissing.errors.txt
index 7c5081aa99576..d55e85ade7c26 100644
--- a/tests/baselines/reference/importTypeLocalMissing.errors.txt
+++ b/tests/baselines/reference/importTypeLocalMissing.errors.txt
@@ -1,7 +1,7 @@
-tests/cases/conformance/types/import/usage.ts(1,24): error TS2307: Cannot find module './fo'.
-tests/cases/conformance/types/import/usage.ts(2,22): error TS2307: Cannot find module './fo2'.
+tests/cases/conformance/types/import/usage.ts(1,24): error TS2307: Cannot find module './fo' or its corresponding type declarations.
+tests/cases/conformance/types/import/usage.ts(2,22): error TS2307: Cannot find module './fo2' or its corresponding type declarations.
 tests/cases/conformance/types/import/usage.ts(3,36): error TS2694: Namespace '"tests/cases/conformance/types/import/foo2".Bar' has no exported member 'Q'.
-tests/cases/conformance/types/import/usage.ts(10,32): error TS2307: Cannot find module './fo2'.
+tests/cases/conformance/types/import/usage.ts(10,32): error TS2307: Cannot find module './fo2' or its corresponding type declarations.
 
 
 ==== tests/cases/conformance/types/import/foo.ts (0 errors) ====
@@ -35,10 +35,10 @@ tests/cases/conformance/types/import/usage.ts(10,32): error TS2307: Cannot find
 ==== tests/cases/conformance/types/import/usage.ts (4 errors) ====
     export const x: import("./fo") = { x: 0, y: 0 };
                            ~~~~~~
-!!! error TS2307: Cannot find module './fo'.
+!!! error TS2307: Cannot find module './fo' or its corresponding type declarations.
     export let y: import("./fo2").Bar.I = { a: "", b: 0 };
                          ~~~~~~~
-!!! error TS2307: Cannot find module './fo2'.
+!!! error TS2307: Cannot find module './fo2' or its corresponding type declarations.
     export let z: import("./foo2").Bar.Q = { a: "", b: 0 };
                                        ~
 !!! error TS2694: Namespace '"tests/cases/conformance/types/import/foo2".Bar' has no exported member 'Q'.
@@ -50,7 +50,7 @@ tests/cases/conformance/types/import/usage.ts(10,32): error TS2307: Cannot find
     
     export let shim: typeof import("./fo2") = {
                                    ~~~~~~~
-!!! error TS2307: Cannot find module './fo2'.
+!!! error TS2307: Cannot find module './fo2' or its corresponding type declarations.
         Bar: Bar2
     };
     
\ No newline at end of file
diff --git a/tests/baselines/reference/importTypeWithUnparenthesizedGenericFunctionParsed.errors.txt b/tests/baselines/reference/importTypeWithUnparenthesizedGenericFunctionParsed.errors.txt
index 4c40245d8da55..ea1c54c43d71c 100644
--- a/tests/baselines/reference/importTypeWithUnparenthesizedGenericFunctionParsed.errors.txt
+++ b/tests/baselines/reference/importTypeWithUnparenthesizedGenericFunctionParsed.errors.txt
@@ -1,7 +1,7 @@
-tests/cases/compiler/importTypeWithUnparenthesizedGenericFunctionParsed.ts(1,36): error TS2307: Cannot find module 'module'.
+tests/cases/compiler/importTypeWithUnparenthesizedGenericFunctionParsed.ts(1,36): error TS2307: Cannot find module 'module' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/importTypeWithUnparenthesizedGenericFunctionParsed.ts (1 errors) ====
     export declare const fail1: import("module").Modifier<<T>(x: T) => T>; // shouldn't be a parse error
                                        ~~~~~~~~
-!!! error TS2307: Cannot find module 'module'.
\ No newline at end of file
+!!! error TS2307: Cannot find module 'module' or its corresponding type declarations.
\ No newline at end of file
diff --git a/tests/baselines/reference/importWithTrailingSlash_noResolve.errors.txt b/tests/baselines/reference/importWithTrailingSlash_noResolve.errors.txt
index e501cc5d432fc..ee38b96c74be9 100644
--- a/tests/baselines/reference/importWithTrailingSlash_noResolve.errors.txt
+++ b/tests/baselines/reference/importWithTrailingSlash_noResolve.errors.txt
@@ -1,8 +1,8 @@
-/a.ts(1,17): error TS2307: Cannot find module './foo/'.
+/a.ts(1,17): error TS2307: Cannot find module './foo/' or its corresponding type declarations.
 
 
 ==== /a.ts (1 errors) ====
     import foo from "./foo/";
                     ~~~~~~~~
-!!! error TS2307: Cannot find module './foo/'.
+!!! error TS2307: Cannot find module './foo/' or its corresponding type declarations.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/isolatedModulesImportExportElision.errors.txt b/tests/baselines/reference/isolatedModulesImportExportElision.errors.txt
index c536f48763756..634afb2e780ad 100644
--- a/tests/baselines/reference/isolatedModulesImportExportElision.errors.txt
+++ b/tests/baselines/reference/isolatedModulesImportExportElision.errors.txt
@@ -1,19 +1,19 @@
-tests/cases/compiler/file1.ts(1,17): error TS2307: Cannot find module 'module'.
-tests/cases/compiler/file1.ts(2,18): error TS2307: Cannot find module 'module'.
-tests/cases/compiler/file1.ts(3,21): error TS2307: Cannot find module 'module'.
-tests/cases/compiler/file1.ts(11,18): error TS2307: Cannot find module 'module'.
+tests/cases/compiler/file1.ts(1,17): error TS2307: Cannot find module 'module' or its corresponding type declarations.
+tests/cases/compiler/file1.ts(2,18): error TS2307: Cannot find module 'module' or its corresponding type declarations.
+tests/cases/compiler/file1.ts(3,21): error TS2307: Cannot find module 'module' or its corresponding type declarations.
+tests/cases/compiler/file1.ts(11,18): error TS2307: Cannot find module 'module' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/file1.ts (4 errors) ====
     import {c} from "module"
                     ~~~~~~~~
-!!! error TS2307: Cannot find module 'module'.
+!!! error TS2307: Cannot find module 'module' or its corresponding type declarations.
     import {c2} from "module"
                      ~~~~~~~~
-!!! error TS2307: Cannot find module 'module'.
+!!! error TS2307: Cannot find module 'module' or its corresponding type declarations.
     import * as ns from "module"
                         ~~~~~~~~
-!!! error TS2307: Cannot find module 'module'.
+!!! error TS2307: Cannot find module 'module' or its corresponding type declarations.
     
     class C extends c2.C {
     }
@@ -23,5 +23,5 @@ tests/cases/compiler/file1.ts(11,18): error TS2307: Cannot find module 'module'.
     
     export {c1} from "module";
                      ~~~~~~~~
-!!! error TS2307: Cannot find module 'module'.
+!!! error TS2307: Cannot find module 'module' or its corresponding type declarations.
     export var z = x;
\ No newline at end of file
diff --git a/tests/baselines/reference/literalTypeNameAssertionNotTriggered.errors.txt b/tests/baselines/reference/literalTypeNameAssertionNotTriggered.errors.txt
index e7b16c340102b..35c9c1618b1a2 100644
--- a/tests/baselines/reference/literalTypeNameAssertionNotTriggered.errors.txt
+++ b/tests/baselines/reference/literalTypeNameAssertionNotTriggered.errors.txt
@@ -1,4 +1,4 @@
-/a.ts(1,20): error TS2307: Cannot find module 'something'.
+/a.ts(1,20): error TS2307: Cannot find module 'something' or its corresponding type declarations.
 /b.ts(3,6): error TS2345: Argument of type '""' is not assignable to parameter of type '"x"'.
 
 
@@ -12,6 +12,6 @@
 ==== /a.ts (1 errors) ====
     import x = require("something");
                        ~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'something'.
+!!! error TS2307: Cannot find module 'something' or its corresponding type declarations.
     export { x };
     
\ No newline at end of file
diff --git a/tests/baselines/reference/metadataImportType.errors.txt b/tests/baselines/reference/metadataImportType.errors.txt
index 2b0f709736ded..e5d0c1198b1ee 100644
--- a/tests/baselines/reference/metadataImportType.errors.txt
+++ b/tests/baselines/reference/metadataImportType.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/compiler/metadataImportType.ts(2,6): error TS2582: Cannot find name 'test'. Do you need to install type definitions for a test runner? Try `npm i @types/jest` or `npm i @types/mocha`.
-tests/cases/compiler/metadataImportType.ts(3,15): error TS2307: Cannot find module './b'.
+tests/cases/compiler/metadataImportType.ts(3,15): error TS2307: Cannot find module './b' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/metadataImportType.ts (2 errors) ====
@@ -9,5 +9,5 @@ tests/cases/compiler/metadataImportType.ts(3,15): error TS2307: Cannot find modu
 !!! error TS2582: Cannot find name 'test'. Do you need to install type definitions for a test runner? Try `npm i @types/jest` or `npm i @types/mocha`.
         b: import('./b').B
                   ~~~~~
-!!! error TS2307: Cannot find module './b'.
+!!! error TS2307: Cannot find module './b' or its corresponding type declarations.
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/moduleAugmentationDisallowedExtensions.errors.txt b/tests/baselines/reference/moduleAugmentationDisallowedExtensions.errors.txt
index cacd821168cd8..af46d49929593 100644
--- a/tests/baselines/reference/moduleAugmentationDisallowedExtensions.errors.txt
+++ b/tests/baselines/reference/moduleAugmentationDisallowedExtensions.errors.txt
@@ -1,11 +1,11 @@
 tests/cases/compiler/x.ts(17,5): error TS2667: Imports are not permitted in module augmentations. Consider moving them to the enclosing external module.
-tests/cases/compiler/x.ts(17,26): error TS2307: Cannot find module './x0'.
+tests/cases/compiler/x.ts(17,26): error TS2307: Cannot find module './x0' or its corresponding type declarations.
 tests/cases/compiler/x.ts(18,5): error TS2667: Imports are not permitted in module augmentations. Consider moving them to the enclosing external module.
-tests/cases/compiler/x.ts(18,21): error TS2307: Cannot find module './x0'.
+tests/cases/compiler/x.ts(18,21): error TS2307: Cannot find module './x0' or its corresponding type declarations.
 tests/cases/compiler/x.ts(19,5): error TS2666: Exports and export assignments are not permitted in module augmentations.
-tests/cases/compiler/x.ts(19,19): error TS2307: Cannot find module './x0'.
+tests/cases/compiler/x.ts(19,19): error TS2307: Cannot find module './x0' or its corresponding type declarations.
 tests/cases/compiler/x.ts(20,5): error TS2666: Exports and export assignments are not permitted in module augmentations.
-tests/cases/compiler/x.ts(20,21): error TS2307: Cannot find module './x0'.
+tests/cases/compiler/x.ts(20,21): error TS2307: Cannot find module './x0' or its corresponding type declarations.
 tests/cases/compiler/x.ts(24,5): error TS2666: Exports and export assignments are not permitted in module augmentations.
 
 
@@ -33,22 +33,22 @@ tests/cases/compiler/x.ts(24,5): error TS2666: Exports and export assignments ar
         ~~~~~~
 !!! error TS2667: Imports are not permitted in module augmentations. Consider moving them to the enclosing external module.
                              ~~~~~~
-!!! error TS2307: Cannot find module './x0'.
+!!! error TS2307: Cannot find module './x0' or its corresponding type declarations.
         import {a} from "./x0";
         ~~~~~~
 !!! error TS2667: Imports are not permitted in module augmentations. Consider moving them to the enclosing external module.
                         ~~~~~~
-!!! error TS2307: Cannot find module './x0'.
+!!! error TS2307: Cannot find module './x0' or its corresponding type declarations.
         export * from "./x0";
         ~~~~~~
 !!! error TS2666: Exports and export assignments are not permitted in module augmentations.
                       ~~~~~~
-!!! error TS2307: Cannot find module './x0'.
+!!! error TS2307: Cannot find module './x0' or its corresponding type declarations.
         export {a} from "./x0";
         ~~~~~~
 !!! error TS2666: Exports and export assignments are not permitted in module augmentations.
                         ~~~~~~
-!!! error TS2307: Cannot find module './x0'.
+!!! error TS2307: Cannot find module './x0' or its corresponding type declarations.
     }
     
     declare module "./test" {
diff --git a/tests/baselines/reference/moduleAugmentationImportsAndExports2.errors.txt b/tests/baselines/reference/moduleAugmentationImportsAndExports2.errors.txt
index a3e41fa38e72a..3c686caad5588 100644
--- a/tests/baselines/reference/moduleAugmentationImportsAndExports2.errors.txt
+++ b/tests/baselines/reference/moduleAugmentationImportsAndExports2.errors.txt
@@ -1,8 +1,8 @@
 tests/cases/compiler/f3.ts(3,13): error TS2339: Property 'foo' does not exist on type 'A'.
 tests/cases/compiler/f3.ts(11,5): error TS2667: Imports are not permitted in module augmentations. Consider moving them to the enclosing external module.
-tests/cases/compiler/f3.ts(11,21): error TS2307: Cannot find module './f2'.
+tests/cases/compiler/f3.ts(11,21): error TS2307: Cannot find module './f2' or its corresponding type declarations.
 tests/cases/compiler/f3.ts(12,5): error TS2666: Exports and export assignments are not permitted in module augmentations.
-tests/cases/compiler/f3.ts(12,21): error TS2307: Cannot find module './f2'.
+tests/cases/compiler/f3.ts(12,21): error TS2307: Cannot find module './f2' or its corresponding type declarations.
 tests/cases/compiler/f3.ts(13,5): error TS2667: Imports are not permitted in module augmentations. Consider moving them to the enclosing external module.
 tests/cases/compiler/f3.ts(14,5): error TS2667: Imports are not permitted in module augmentations. Consider moving them to the enclosing external module.
 tests/cases/compiler/f4.ts(5,11): error TS2339: Property 'foo' does not exist on type 'A'.
@@ -33,12 +33,12 @@ tests/cases/compiler/f4.ts(5,11): error TS2339: Property 'foo' does not exist on
         ~~~~~~
 !!! error TS2667: Imports are not permitted in module augmentations. Consider moving them to the enclosing external module.
                         ~~~~~~
-!!! error TS2307: Cannot find module './f2'.
+!!! error TS2307: Cannot find module './f2' or its corresponding type declarations.
         export {B} from "./f2";
         ~~~~~~
 !!! error TS2666: Exports and export assignments are not permitted in module augmentations.
                         ~~~~~~
-!!! error TS2307: Cannot find module './f2'.
+!!! error TS2307: Cannot find module './f2' or its corresponding type declarations.
         import I = N.Ifc;
         ~~~~~~
 !!! error TS2667: Imports are not permitted in module augmentations. Consider moving them to the enclosing external module.
diff --git a/tests/baselines/reference/moduleAugmentationImportsAndExports3.errors.txt b/tests/baselines/reference/moduleAugmentationImportsAndExports3.errors.txt
index 3018d72f1b76f..48c8211d55ed8 100644
--- a/tests/baselines/reference/moduleAugmentationImportsAndExports3.errors.txt
+++ b/tests/baselines/reference/moduleAugmentationImportsAndExports3.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/compiler/f3.ts(11,5): error TS2667: Imports are not permitted in module augmentations. Consider moving them to the enclosing external module.
-tests/cases/compiler/f3.ts(11,21): error TS2307: Cannot find module './f2'.
+tests/cases/compiler/f3.ts(11,21): error TS2307: Cannot find module './f2' or its corresponding type declarations.
 tests/cases/compiler/f3.ts(12,5): error TS2667: Imports are not permitted in module augmentations. Consider moving them to the enclosing external module.
 tests/cases/compiler/f3.ts(13,5): error TS2667: Imports are not permitted in module augmentations. Consider moving them to the enclosing external module.
 
@@ -27,7 +27,7 @@ tests/cases/compiler/f3.ts(13,5): error TS2667: Imports are not permitted in mod
         ~~~~~~
 !!! error TS2667: Imports are not permitted in module augmentations. Consider moving them to the enclosing external module.
                         ~~~~~~
-!!! error TS2307: Cannot find module './f2'.
+!!! error TS2307: Cannot find module './f2' or its corresponding type declarations.
         import I = N.Ifc;
         ~~~~~~
 !!! error TS2667: Imports are not permitted in module augmentations. Consider moving them to the enclosing external module.
diff --git a/tests/baselines/reference/noAssertForUnparseableTypedefs.errors.txt b/tests/baselines/reference/noAssertForUnparseableTypedefs.errors.txt
index bacaab76e4d15..914dd87771211 100644
--- a/tests/baselines/reference/noAssertForUnparseableTypedefs.errors.txt
+++ b/tests/baselines/reference/noAssertForUnparseableTypedefs.errors.txt
@@ -1,9 +1,9 @@
-tests/cases/conformance/jsdoc/bug26693.js(2,22): error TS2307: Cannot find module 'nope'.
+tests/cases/conformance/jsdoc/bug26693.js(2,22): error TS2307: Cannot find module 'nope' or its corresponding type declarations.
 
 
 ==== tests/cases/conformance/jsdoc/bug26693.js (1 errors) ====
     /** @typedef {module:locale} hi */
     import { nope } from 'nope';
                          ~~~~~~
-!!! error TS2307: Cannot find module 'nope'.
+!!! error TS2307: Cannot find module 'nope' or its corresponding type declarations.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/packageJsonMain_isNonRecursive.errors.txt b/tests/baselines/reference/packageJsonMain_isNonRecursive.errors.txt
index d7e80990bc16d..bf5a281cd1e53 100644
--- a/tests/baselines/reference/packageJsonMain_isNonRecursive.errors.txt
+++ b/tests/baselines/reference/packageJsonMain_isNonRecursive.errors.txt
@@ -1,10 +1,10 @@
-/a.ts(1,22): error TS2307: Cannot find module 'foo'.
+/a.ts(1,22): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
 
 
 ==== /a.ts (1 errors) ====
     import foo = require("foo");
                          ~~~~~
-!!! error TS2307: Cannot find module 'foo'.
+!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
     
 ==== /node_modules/foo/package.json (0 errors) ====
     { "main": "oof" }
diff --git a/tests/baselines/reference/pathMappingBasedModuleResolution_withExtension_failedLookup.errors.txt b/tests/baselines/reference/pathMappingBasedModuleResolution_withExtension_failedLookup.errors.txt
index 0ebe17354493f..5bbf4b220f7d1 100644
--- a/tests/baselines/reference/pathMappingBasedModuleResolution_withExtension_failedLookup.errors.txt
+++ b/tests/baselines/reference/pathMappingBasedModuleResolution_withExtension_failedLookup.errors.txt
@@ -1,4 +1,4 @@
-/a.ts(1,21): error TS2307: Cannot find module 'foo'.
+/a.ts(1,21): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
 
 
 ==== /tsconfig.json (0 errors) ====
@@ -14,5 +14,5 @@
 ==== /a.ts (1 errors) ====
     import { foo } from "foo";
                         ~~~~~
-!!! error TS2307: Cannot find module 'foo'.
+!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/privacyGloImportParseErrors.errors.txt b/tests/baselines/reference/privacyGloImportParseErrors.errors.txt
index 5118c9012e4cb..2724d972987cf 100644
--- a/tests/baselines/reference/privacyGloImportParseErrors.errors.txt
+++ b/tests/baselines/reference/privacyGloImportParseErrors.errors.txt
@@ -2,9 +2,9 @@ tests/cases/compiler/privacyGloImportParseErrors.ts(22,5): error TS2668: 'export
 tests/cases/compiler/privacyGloImportParseErrors.ts(22,27): error TS2435: Ambient modules cannot be nested in other modules or namespaces.
 tests/cases/compiler/privacyGloImportParseErrors.ts(30,20): error TS2435: Ambient modules cannot be nested in other modules or namespaces.
 tests/cases/compiler/privacyGloImportParseErrors.ts(59,37): error TS1147: Import declarations in a namespace cannot reference a module.
-tests/cases/compiler/privacyGloImportParseErrors.ts(59,37): error TS2307: Cannot find module 'm1_M3_public'.
+tests/cases/compiler/privacyGloImportParseErrors.ts(59,37): error TS2307: Cannot find module 'm1_M3_public' or its corresponding type declarations.
 tests/cases/compiler/privacyGloImportParseErrors.ts(69,37): error TS1147: Import declarations in a namespace cannot reference a module.
-tests/cases/compiler/privacyGloImportParseErrors.ts(69,37): error TS2307: Cannot find module 'm1_M4_private'.
+tests/cases/compiler/privacyGloImportParseErrors.ts(69,37): error TS2307: Cannot find module 'm1_M4_private' or its corresponding type declarations.
 tests/cases/compiler/privacyGloImportParseErrors.ts(81,43): error TS1147: Import declarations in a namespace cannot reference a module.
 tests/cases/compiler/privacyGloImportParseErrors.ts(82,43): error TS1147: Import declarations in a namespace cannot reference a module.
 tests/cases/compiler/privacyGloImportParseErrors.ts(121,38): error TS1147: Import declarations in a namespace cannot reference a module.
@@ -85,7 +85,7 @@ tests/cases/compiler/privacyGloImportParseErrors.ts(149,29): error TS1147: Impor
                                         ~~~~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                                         ~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'm1_M3_public'.
+!!! error TS2307: Cannot find module 'm1_M3_public' or its corresponding type declarations.
         export var m1_im3_private_v1_public = m1_im3_private.c1;
         export var m1_im3_private_v2_public = new m1_im3_private.c1();
         export var m1_im3_private_v3_public = m1_im3_private.f1;
@@ -99,7 +99,7 @@ tests/cases/compiler/privacyGloImportParseErrors.ts(149,29): error TS1147: Impor
                                         ~~~~~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                                         ~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'm1_M4_private'.
+!!! error TS2307: Cannot find module 'm1_M4_private' or its corresponding type declarations.
         export var m1_im4_private_v1_public = m1_im4_private.c1;
         export var m1_im4_private_v2_public = new m1_im4_private.c1();
         export var m1_im4_private_v3_public = m1_im4_private.f1;
diff --git a/tests/baselines/reference/privacyImportParseErrors.errors.txt b/tests/baselines/reference/privacyImportParseErrors.errors.txt
index b607edf049b44..7a267ec973082 100644
--- a/tests/baselines/reference/privacyImportParseErrors.errors.txt
+++ b/tests/baselines/reference/privacyImportParseErrors.errors.txt
@@ -2,39 +2,39 @@ tests/cases/compiler/privacyImportParseErrors.ts(22,5): error TS2668: 'export' m
 tests/cases/compiler/privacyImportParseErrors.ts(22,27): error TS2435: Ambient modules cannot be nested in other modules or namespaces.
 tests/cases/compiler/privacyImportParseErrors.ts(30,20): error TS2435: Ambient modules cannot be nested in other modules or namespaces.
 tests/cases/compiler/privacyImportParseErrors.ts(59,37): error TS1147: Import declarations in a namespace cannot reference a module.
-tests/cases/compiler/privacyImportParseErrors.ts(59,37): error TS2307: Cannot find module 'm1_M3_public'.
+tests/cases/compiler/privacyImportParseErrors.ts(59,37): error TS2307: Cannot find module 'm1_M3_public' or its corresponding type declarations.
 tests/cases/compiler/privacyImportParseErrors.ts(69,37): error TS1147: Import declarations in a namespace cannot reference a module.
-tests/cases/compiler/privacyImportParseErrors.ts(69,37): error TS2307: Cannot find module 'm1_M4_private'.
+tests/cases/compiler/privacyImportParseErrors.ts(69,37): error TS2307: Cannot find module 'm1_M4_private' or its corresponding type declarations.
 tests/cases/compiler/privacyImportParseErrors.ts(81,43): error TS1147: Import declarations in a namespace cannot reference a module.
 tests/cases/compiler/privacyImportParseErrors.ts(82,43): error TS1147: Import declarations in a namespace cannot reference a module.
 tests/cases/compiler/privacyImportParseErrors.ts(106,5): error TS2668: 'export' modifier cannot be applied to ambient modules and module augmentations since they are always visible.
 tests/cases/compiler/privacyImportParseErrors.ts(106,27): error TS2435: Ambient modules cannot be nested in other modules or namespaces.
 tests/cases/compiler/privacyImportParseErrors.ts(114,20): error TS2435: Ambient modules cannot be nested in other modules or namespaces.
 tests/cases/compiler/privacyImportParseErrors.ts(143,37): error TS1147: Import declarations in a namespace cannot reference a module.
-tests/cases/compiler/privacyImportParseErrors.ts(143,37): error TS2307: Cannot find module 'm2_M3_public'.
+tests/cases/compiler/privacyImportParseErrors.ts(143,37): error TS2307: Cannot find module 'm2_M3_public' or its corresponding type declarations.
 tests/cases/compiler/privacyImportParseErrors.ts(153,37): error TS1147: Import declarations in a namespace cannot reference a module.
-tests/cases/compiler/privacyImportParseErrors.ts(153,37): error TS2307: Cannot find module 'm2_M4_private'.
+tests/cases/compiler/privacyImportParseErrors.ts(153,37): error TS2307: Cannot find module 'm2_M4_private' or its corresponding type declarations.
 tests/cases/compiler/privacyImportParseErrors.ts(166,43): error TS1147: Import declarations in a namespace cannot reference a module.
 tests/cases/compiler/privacyImportParseErrors.ts(167,43): error TS1147: Import declarations in a namespace cannot reference a module.
 tests/cases/compiler/privacyImportParseErrors.ts(180,1): error TS2668: 'export' modifier cannot be applied to ambient modules and module augmentations since they are always visible.
 tests/cases/compiler/privacyImportParseErrors.ts(180,23): error TS2664: Invalid module name in augmentation, module 'glo_M2_public' cannot be found.
 tests/cases/compiler/privacyImportParseErrors.ts(198,1): error TS2668: 'export' modifier cannot be applied to ambient modules and module augmentations since they are always visible.
 tests/cases/compiler/privacyImportParseErrors.ts(198,23): error TS2664: Invalid module name in augmentation, module 'glo_M4_private' cannot be found.
-tests/cases/compiler/privacyImportParseErrors.ts(218,34): error TS2307: Cannot find module 'glo_M2_public'.
-tests/cases/compiler/privacyImportParseErrors.ts(238,34): error TS2307: Cannot find module 'glo_M4_private'.
-tests/cases/compiler/privacyImportParseErrors.ts(251,40): error TS2307: Cannot find module 'glo_M2_public'.
-tests/cases/compiler/privacyImportParseErrors.ts(252,40): error TS2307: Cannot find module 'glo_M4_private'.
+tests/cases/compiler/privacyImportParseErrors.ts(218,34): error TS2307: Cannot find module 'glo_M2_public' or its corresponding type declarations.
+tests/cases/compiler/privacyImportParseErrors.ts(238,34): error TS2307: Cannot find module 'glo_M4_private' or its corresponding type declarations.
+tests/cases/compiler/privacyImportParseErrors.ts(251,40): error TS2307: Cannot find module 'glo_M2_public' or its corresponding type declarations.
+tests/cases/compiler/privacyImportParseErrors.ts(252,40): error TS2307: Cannot find module 'glo_M4_private' or its corresponding type declarations.
 tests/cases/compiler/privacyImportParseErrors.ts(255,1): error TS2668: 'export' modifier cannot be applied to ambient modules and module augmentations since they are always visible.
 tests/cases/compiler/privacyImportParseErrors.ts(255,23): error TS2664: Invalid module name in augmentation, module 'use_glo_M1_public' cannot be found.
 tests/cases/compiler/privacyImportParseErrors.ts(258,45): error TS2709: Cannot use namespace 'use_glo_M1_public' as a type.
 tests/cases/compiler/privacyImportParseErrors.ts(261,39): error TS2709: Cannot use namespace 'use_glo_M1_public' as a type.
-tests/cases/compiler/privacyImportParseErrors.ts(264,40): error TS2307: Cannot find module 'glo_M2_public'.
+tests/cases/compiler/privacyImportParseErrors.ts(264,40): error TS2307: Cannot find module 'glo_M2_public' or its corresponding type declarations.
 tests/cases/compiler/privacyImportParseErrors.ts(273,38): error TS1147: Import declarations in a namespace cannot reference a module.
 tests/cases/compiler/privacyImportParseErrors.ts(277,45): error TS1147: Import declarations in a namespace cannot reference a module.
 tests/cases/compiler/privacyImportParseErrors.ts(284,16): error TS2664: Invalid module name in augmentation, module 'use_glo_M3_private' cannot be found.
 tests/cases/compiler/privacyImportParseErrors.ts(287,46): error TS2709: Cannot use namespace 'use_glo_M3_private' as a type.
 tests/cases/compiler/privacyImportParseErrors.ts(290,40): error TS2709: Cannot use namespace 'use_glo_M3_private' as a type.
-tests/cases/compiler/privacyImportParseErrors.ts(293,41): error TS2307: Cannot find module 'glo_M4_private'.
+tests/cases/compiler/privacyImportParseErrors.ts(293,41): error TS2307: Cannot find module 'glo_M4_private' or its corresponding type declarations.
 tests/cases/compiler/privacyImportParseErrors.ts(302,38): error TS1147: Import declarations in a namespace cannot reference a module.
 tests/cases/compiler/privacyImportParseErrors.ts(306,45): error TS1147: Import declarations in a namespace cannot reference a module.
 tests/cases/compiler/privacyImportParseErrors.ts(312,16): error TS2664: Invalid module name in augmentation, module 'anotherParseError' cannot be found.
@@ -124,7 +124,7 @@ tests/cases/compiler/privacyImportParseErrors.ts(353,29): error TS1147: Import d
                                         ~~~~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                                         ~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'm1_M3_public'.
+!!! error TS2307: Cannot find module 'm1_M3_public' or its corresponding type declarations.
         export var m1_im3_private_v1_public = m1_im3_private.c1;
         export var m1_im3_private_v2_public = new m1_im3_private.c1();
         export var m1_im3_private_v3_public = m1_im3_private.f1;
@@ -138,7 +138,7 @@ tests/cases/compiler/privacyImportParseErrors.ts(353,29): error TS1147: Import d
                                         ~~~~~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                                         ~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'm1_M4_private'.
+!!! error TS2307: Cannot find module 'm1_M4_private' or its corresponding type declarations.
         export var m1_im4_private_v1_public = m1_im4_private.c1;
         export var m1_im4_private_v2_public = new m1_im4_private.c1();
         export var m1_im4_private_v3_public = m1_im4_private.f1;
@@ -226,7 +226,7 @@ tests/cases/compiler/privacyImportParseErrors.ts(353,29): error TS1147: Import d
                                         ~~~~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                                         ~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'm2_M3_public'.
+!!! error TS2307: Cannot find module 'm2_M3_public' or its corresponding type declarations.
         export var m1_im3_private_v1_public = m1_im3_private.c1;
         export var m1_im3_private_v2_public = new m1_im3_private.c1();
         export var m1_im3_private_v3_public = m1_im3_private.f1;
@@ -240,7 +240,7 @@ tests/cases/compiler/privacyImportParseErrors.ts(353,29): error TS1147: Import d
                                         ~~~~~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                                         ~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'm2_M4_private'.
+!!! error TS2307: Cannot find module 'm2_M4_private' or its corresponding type declarations.
         export var m1_im4_private_v1_public = m1_im4_private.c1;
         export var m1_im4_private_v2_public = new m1_im4_private.c1();
         export var m1_im4_private_v3_public = m1_im4_private.f1;
@@ -319,7 +319,7 @@ tests/cases/compiler/privacyImportParseErrors.ts(353,29): error TS1147: Import d
     
     import glo_im2_private = require("glo_M2_public");
                                      ~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'glo_M2_public'.
+!!! error TS2307: Cannot find module 'glo_M2_public' or its corresponding type declarations.
     export var glo_im2_private_v1_public = glo_im2_private.c1;
     export var glo_im2_private_v2_public = new glo_im2_private.c1();
     export var glo_im2_private_v3_public = glo_im2_private.f1;
@@ -341,7 +341,7 @@ tests/cases/compiler/privacyImportParseErrors.ts(353,29): error TS1147: Import d
     
     import glo_im4_private = require("glo_M4_private");
                                      ~~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'glo_M4_private'.
+!!! error TS2307: Cannot find module 'glo_M4_private' or its corresponding type declarations.
     export var glo_im4_private_v1_public = glo_im4_private.c1;
     export var glo_im4_private_v2_public = new glo_im4_private.c1();
     export var glo_im4_private_v3_public = glo_im4_private.f1;
@@ -356,10 +356,10 @@ tests/cases/compiler/privacyImportParseErrors.ts(353,29): error TS1147: Import d
     export import glo_im2_public = glo_M3_private;
     export import glo_im3_public = require("glo_M2_public");
                                            ~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'glo_M2_public'.
+!!! error TS2307: Cannot find module 'glo_M2_public' or its corresponding type declarations.
     export import glo_im4_public = require("glo_M4_private");
                                            ~~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'glo_M4_private'.
+!!! error TS2307: Cannot find module 'glo_M4_private' or its corresponding type declarations.
     
     
     export declare module "use_glo_M1_public" {
@@ -381,7 +381,7 @@ tests/cases/compiler/privacyImportParseErrors.ts(353,29): error TS1147: Import d
     
         import use_glo_M2_public = require("glo_M2_public");
                                            ~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'glo_M2_public'.
+!!! error TS2307: Cannot find module 'glo_M2_public' or its corresponding type declarations.
         export var use_glo_M2_public_v1_public: { new (): use_glo_M2_public.c1; };
         export var use_glo_M2_public_v2_public: use_glo_M2_public;
         export var use_glo_M2_public_v3_public: () => use_glo_M2_public.c1;
@@ -422,7 +422,7 @@ tests/cases/compiler/privacyImportParseErrors.ts(353,29): error TS1147: Import d
     
         import use_glo_M4_private = require("glo_M4_private");
                                             ~~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'glo_M4_private'.
+!!! error TS2307: Cannot find module 'glo_M4_private' or its corresponding type declarations.
         export var use_glo_M4_private_v1_public: { new (): use_glo_M4_private.c1; };
         export var use_glo_M4_private_v2_public: use_glo_M4_private;
         export var use_glo_M4_private_v3_public: () => use_glo_M4_private.c1;
diff --git a/tests/baselines/reference/project/cantFindTheModule/amd/cantFindTheModule.errors.txt b/tests/baselines/reference/project/cantFindTheModule/amd/cantFindTheModule.errors.txt
index e9f8842d5cbb5..72835d5511dac 100644
--- a/tests/baselines/reference/project/cantFindTheModule/amd/cantFindTheModule.errors.txt
+++ b/tests/baselines/reference/project/cantFindTheModule/amd/cantFindTheModule.errors.txt
@@ -1,18 +1,18 @@
-decl.ts(1,26): error TS2307: Cannot find module './foo/bar.tx'.
-decl.ts(2,26): error TS2307: Cannot find module 'baz'.
-decl.ts(3,26): error TS2307: Cannot find module './baz'.
+decl.ts(1,26): error TS2307: Cannot find module './foo/bar.tx' or its corresponding type declarations.
+decl.ts(2,26): error TS2307: Cannot find module 'baz' or its corresponding type declarations.
+decl.ts(3,26): error TS2307: Cannot find module './baz' or its corresponding type declarations.
 
 
 ==== decl.ts (3 errors) ====
     import modErr  = require("./foo/bar.tx");
                              ~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module './foo/bar.tx'.
+!!! error TS2307: Cannot find module './foo/bar.tx' or its corresponding type declarations.
     import modErr1 = require("baz");
                              ~~~~~
-!!! error TS2307: Cannot find module 'baz'.
+!!! error TS2307: Cannot find module 'baz' or its corresponding type declarations.
     import modErr2 = require("./baz");
                              ~~~~~~~
-!!! error TS2307: Cannot find module './baz'.
+!!! error TS2307: Cannot find module './baz' or its corresponding type declarations.
     
     //import modErr1 = require("\bar");
     
diff --git a/tests/baselines/reference/project/cantFindTheModule/node/cantFindTheModule.errors.txt b/tests/baselines/reference/project/cantFindTheModule/node/cantFindTheModule.errors.txt
index e9f8842d5cbb5..72835d5511dac 100644
--- a/tests/baselines/reference/project/cantFindTheModule/node/cantFindTheModule.errors.txt
+++ b/tests/baselines/reference/project/cantFindTheModule/node/cantFindTheModule.errors.txt
@@ -1,18 +1,18 @@
-decl.ts(1,26): error TS2307: Cannot find module './foo/bar.tx'.
-decl.ts(2,26): error TS2307: Cannot find module 'baz'.
-decl.ts(3,26): error TS2307: Cannot find module './baz'.
+decl.ts(1,26): error TS2307: Cannot find module './foo/bar.tx' or its corresponding type declarations.
+decl.ts(2,26): error TS2307: Cannot find module 'baz' or its corresponding type declarations.
+decl.ts(3,26): error TS2307: Cannot find module './baz' or its corresponding type declarations.
 
 
 ==== decl.ts (3 errors) ====
     import modErr  = require("./foo/bar.tx");
                              ~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module './foo/bar.tx'.
+!!! error TS2307: Cannot find module './foo/bar.tx' or its corresponding type declarations.
     import modErr1 = require("baz");
                              ~~~~~
-!!! error TS2307: Cannot find module 'baz'.
+!!! error TS2307: Cannot find module 'baz' or its corresponding type declarations.
     import modErr2 = require("./baz");
                              ~~~~~~~
-!!! error TS2307: Cannot find module './baz'.
+!!! error TS2307: Cannot find module './baz' or its corresponding type declarations.
     
     //import modErr1 = require("\bar");
     
diff --git a/tests/baselines/reference/project/emitDecoratorMetadataCommonJSISolatedModules/amd/emitDecoratorMetadataCommonJSISolatedModules.errors.txt b/tests/baselines/reference/project/emitDecoratorMetadataCommonJSISolatedModules/amd/emitDecoratorMetadataCommonJSISolatedModules.errors.txt
index f6ad25fddb1d9..30eeb8a44d2bf 100644
--- a/tests/baselines/reference/project/emitDecoratorMetadataCommonJSISolatedModules/amd/emitDecoratorMetadataCommonJSISolatedModules.errors.txt
+++ b/tests/baselines/reference/project/emitDecoratorMetadataCommonJSISolatedModules/amd/emitDecoratorMetadataCommonJSISolatedModules.errors.txt
@@ -1,4 +1,4 @@
-main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
+main.ts(1,21): error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
 
 
 ==== tsconfig.json (0 errors) ====
@@ -18,7 +18,7 @@ main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
 ==== main.ts (1 errors) ====
     import * as ng from "angular2/core";
                         ~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'angular2/core'.
+!!! error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
     
     declare function foo(...args: any[]);
     
diff --git a/tests/baselines/reference/project/emitDecoratorMetadataCommonJSISolatedModules/node/emitDecoratorMetadataCommonJSISolatedModules.errors.txt b/tests/baselines/reference/project/emitDecoratorMetadataCommonJSISolatedModules/node/emitDecoratorMetadataCommonJSISolatedModules.errors.txt
index f6ad25fddb1d9..30eeb8a44d2bf 100644
--- a/tests/baselines/reference/project/emitDecoratorMetadataCommonJSISolatedModules/node/emitDecoratorMetadataCommonJSISolatedModules.errors.txt
+++ b/tests/baselines/reference/project/emitDecoratorMetadataCommonJSISolatedModules/node/emitDecoratorMetadataCommonJSISolatedModules.errors.txt
@@ -1,4 +1,4 @@
-main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
+main.ts(1,21): error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
 
 
 ==== tsconfig.json (0 errors) ====
@@ -18,7 +18,7 @@ main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
 ==== main.ts (1 errors) ====
     import * as ng from "angular2/core";
                         ~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'angular2/core'.
+!!! error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
     
     declare function foo(...args: any[]);
     
diff --git a/tests/baselines/reference/project/emitDecoratorMetadataCommonJSISolatedModulesNoResolve/amd/emitDecoratorMetadataCommonJSISolatedModulesNoResolve.errors.txt b/tests/baselines/reference/project/emitDecoratorMetadataCommonJSISolatedModulesNoResolve/amd/emitDecoratorMetadataCommonJSISolatedModulesNoResolve.errors.txt
index f4fe440f379c5..5c605973feaf1 100644
--- a/tests/baselines/reference/project/emitDecoratorMetadataCommonJSISolatedModulesNoResolve/amd/emitDecoratorMetadataCommonJSISolatedModulesNoResolve.errors.txt
+++ b/tests/baselines/reference/project/emitDecoratorMetadataCommonJSISolatedModulesNoResolve/amd/emitDecoratorMetadataCommonJSISolatedModulesNoResolve.errors.txt
@@ -1,4 +1,4 @@
-main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
+main.ts(1,21): error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
 
 
 ==== tsconfig.json (0 errors) ====
@@ -19,7 +19,7 @@ main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
 ==== main.ts (1 errors) ====
     import * as ng from "angular2/core";
                         ~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'angular2/core'.
+!!! error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
     
     declare function foo(...args: any[]);
     
diff --git a/tests/baselines/reference/project/emitDecoratorMetadataCommonJSISolatedModulesNoResolve/node/emitDecoratorMetadataCommonJSISolatedModulesNoResolve.errors.txt b/tests/baselines/reference/project/emitDecoratorMetadataCommonJSISolatedModulesNoResolve/node/emitDecoratorMetadataCommonJSISolatedModulesNoResolve.errors.txt
index f4fe440f379c5..5c605973feaf1 100644
--- a/tests/baselines/reference/project/emitDecoratorMetadataCommonJSISolatedModulesNoResolve/node/emitDecoratorMetadataCommonJSISolatedModulesNoResolve.errors.txt
+++ b/tests/baselines/reference/project/emitDecoratorMetadataCommonJSISolatedModulesNoResolve/node/emitDecoratorMetadataCommonJSISolatedModulesNoResolve.errors.txt
@@ -1,4 +1,4 @@
-main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
+main.ts(1,21): error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
 
 
 ==== tsconfig.json (0 errors) ====
@@ -19,7 +19,7 @@ main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
 ==== main.ts (1 errors) ====
     import * as ng from "angular2/core";
                         ~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'angular2/core'.
+!!! error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
     
     declare function foo(...args: any[]);
     
diff --git a/tests/baselines/reference/project/emitDecoratorMetadataSystemJS/amd/emitDecoratorMetadataSystemJS.errors.txt b/tests/baselines/reference/project/emitDecoratorMetadataSystemJS/amd/emitDecoratorMetadataSystemJS.errors.txt
index bd34d2edc4e0e..b5d32ac83951d 100644
--- a/tests/baselines/reference/project/emitDecoratorMetadataSystemJS/amd/emitDecoratorMetadataSystemJS.errors.txt
+++ b/tests/baselines/reference/project/emitDecoratorMetadataSystemJS/amd/emitDecoratorMetadataSystemJS.errors.txt
@@ -1,4 +1,4 @@
-main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
+main.ts(1,21): error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
 
 
 ==== tsconfig.json (0 errors) ====
@@ -17,7 +17,7 @@ main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
 ==== main.ts (1 errors) ====
     import * as ng from "angular2/core";
                         ~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'angular2/core'.
+!!! error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
     
     declare function foo(...args: any[]);
     
diff --git a/tests/baselines/reference/project/emitDecoratorMetadataSystemJS/node/emitDecoratorMetadataSystemJS.errors.txt b/tests/baselines/reference/project/emitDecoratorMetadataSystemJS/node/emitDecoratorMetadataSystemJS.errors.txt
index bd34d2edc4e0e..b5d32ac83951d 100644
--- a/tests/baselines/reference/project/emitDecoratorMetadataSystemJS/node/emitDecoratorMetadataSystemJS.errors.txt
+++ b/tests/baselines/reference/project/emitDecoratorMetadataSystemJS/node/emitDecoratorMetadataSystemJS.errors.txt
@@ -1,4 +1,4 @@
-main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
+main.ts(1,21): error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
 
 
 ==== tsconfig.json (0 errors) ====
@@ -17,7 +17,7 @@ main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
 ==== main.ts (1 errors) ====
     import * as ng from "angular2/core";
                         ~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'angular2/core'.
+!!! error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
     
     declare function foo(...args: any[]);
     
diff --git a/tests/baselines/reference/project/emitDecoratorMetadataSystemJSISolatedModules/amd/emitDecoratorMetadataSystemJSISolatedModules.errors.txt b/tests/baselines/reference/project/emitDecoratorMetadataSystemJSISolatedModules/amd/emitDecoratorMetadataSystemJSISolatedModules.errors.txt
index b14b090b83964..a9514189f2165 100644
--- a/tests/baselines/reference/project/emitDecoratorMetadataSystemJSISolatedModules/amd/emitDecoratorMetadataSystemJSISolatedModules.errors.txt
+++ b/tests/baselines/reference/project/emitDecoratorMetadataSystemJSISolatedModules/amd/emitDecoratorMetadataSystemJSISolatedModules.errors.txt
@@ -1,4 +1,4 @@
-main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
+main.ts(1,21): error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
 
 
 ==== tsconfig.json (0 errors) ====
@@ -19,7 +19,7 @@ main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
 ==== main.ts (1 errors) ====
     import * as ng from "angular2/core";
                         ~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'angular2/core'.
+!!! error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
     
     declare function foo(...args: any[]);
     
diff --git a/tests/baselines/reference/project/emitDecoratorMetadataSystemJSISolatedModules/node/emitDecoratorMetadataSystemJSISolatedModules.errors.txt b/tests/baselines/reference/project/emitDecoratorMetadataSystemJSISolatedModules/node/emitDecoratorMetadataSystemJSISolatedModules.errors.txt
index b14b090b83964..a9514189f2165 100644
--- a/tests/baselines/reference/project/emitDecoratorMetadataSystemJSISolatedModules/node/emitDecoratorMetadataSystemJSISolatedModules.errors.txt
+++ b/tests/baselines/reference/project/emitDecoratorMetadataSystemJSISolatedModules/node/emitDecoratorMetadataSystemJSISolatedModules.errors.txt
@@ -1,4 +1,4 @@
-main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
+main.ts(1,21): error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
 
 
 ==== tsconfig.json (0 errors) ====
@@ -19,7 +19,7 @@ main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
 ==== main.ts (1 errors) ====
     import * as ng from "angular2/core";
                         ~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'angular2/core'.
+!!! error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
     
     declare function foo(...args: any[]);
     
diff --git a/tests/baselines/reference/project/emitDecoratorMetadataSystemJSISolatedModulesNoResolve/amd/emitDecoratorMetadataSystemJSISolatedModulesNoResolve.errors.txt b/tests/baselines/reference/project/emitDecoratorMetadataSystemJSISolatedModulesNoResolve/amd/emitDecoratorMetadataSystemJSISolatedModulesNoResolve.errors.txt
index 99fc00df24a34..3852af98200bc 100644
--- a/tests/baselines/reference/project/emitDecoratorMetadataSystemJSISolatedModulesNoResolve/amd/emitDecoratorMetadataSystemJSISolatedModulesNoResolve.errors.txt
+++ b/tests/baselines/reference/project/emitDecoratorMetadataSystemJSISolatedModulesNoResolve/amd/emitDecoratorMetadataSystemJSISolatedModulesNoResolve.errors.txt
@@ -1,4 +1,4 @@
-main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
+main.ts(1,21): error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
 
 
 ==== tsconfig.json (0 errors) ====
@@ -20,7 +20,7 @@ main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
 ==== main.ts (1 errors) ====
     import * as ng from "angular2/core";
                         ~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'angular2/core'.
+!!! error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
     
     declare function foo(...args: any[]);
     
diff --git a/tests/baselines/reference/project/emitDecoratorMetadataSystemJSISolatedModulesNoResolve/node/emitDecoratorMetadataSystemJSISolatedModulesNoResolve.errors.txt b/tests/baselines/reference/project/emitDecoratorMetadataSystemJSISolatedModulesNoResolve/node/emitDecoratorMetadataSystemJSISolatedModulesNoResolve.errors.txt
index 99fc00df24a34..3852af98200bc 100644
--- a/tests/baselines/reference/project/emitDecoratorMetadataSystemJSISolatedModulesNoResolve/node/emitDecoratorMetadataSystemJSISolatedModulesNoResolve.errors.txt
+++ b/tests/baselines/reference/project/emitDecoratorMetadataSystemJSISolatedModulesNoResolve/node/emitDecoratorMetadataSystemJSISolatedModulesNoResolve.errors.txt
@@ -1,4 +1,4 @@
-main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
+main.ts(1,21): error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
 
 
 ==== tsconfig.json (0 errors) ====
@@ -20,7 +20,7 @@ main.ts(1,21): error TS2307: Cannot find module 'angular2/core'.
 ==== main.ts (1 errors) ====
     import * as ng from "angular2/core";
                         ~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'angular2/core'.
+!!! error TS2307: Cannot find module 'angular2/core' or its corresponding type declarations.
     
     declare function foo(...args: any[]);
     
diff --git a/tests/baselines/reference/project/intReferencingExtAndInt/amd/intReferencingExtAndInt.errors.txt b/tests/baselines/reference/project/intReferencingExtAndInt/amd/intReferencingExtAndInt.errors.txt
index c4ad5e69c83d8..c6d05210818f1 100644
--- a/tests/baselines/reference/project/intReferencingExtAndInt/amd/intReferencingExtAndInt.errors.txt
+++ b/tests/baselines/reference/project/intReferencingExtAndInt/amd/intReferencingExtAndInt.errors.txt
@@ -1,5 +1,5 @@
 internal2.ts(2,21): error TS1147: Import declarations in a namespace cannot reference a module.
-internal2.ts(2,21): error TS2307: Cannot find module 'external2'.
+internal2.ts(2,21): error TS2307: Cannot find module 'external2' or its corresponding type declarations.
 
 
 ==== internal2.ts (2 errors) ====
@@ -8,7 +8,7 @@ internal2.ts(2,21): error TS2307: Cannot find module 'external2'.
     	                   ~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
     	                   ~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'external2'.
+!!! error TS2307: Cannot find module 'external2' or its corresponding type declarations.
     	export var a = g.square(5);
     	export var b = "foo";
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/project/intReferencingExtAndInt/node/intReferencingExtAndInt.errors.txt b/tests/baselines/reference/project/intReferencingExtAndInt/node/intReferencingExtAndInt.errors.txt
index c4ad5e69c83d8..c6d05210818f1 100644
--- a/tests/baselines/reference/project/intReferencingExtAndInt/node/intReferencingExtAndInt.errors.txt
+++ b/tests/baselines/reference/project/intReferencingExtAndInt/node/intReferencingExtAndInt.errors.txt
@@ -1,5 +1,5 @@
 internal2.ts(2,21): error TS1147: Import declarations in a namespace cannot reference a module.
-internal2.ts(2,21): error TS2307: Cannot find module 'external2'.
+internal2.ts(2,21): error TS2307: Cannot find module 'external2' or its corresponding type declarations.
 
 
 ==== internal2.ts (2 errors) ====
@@ -8,7 +8,7 @@ internal2.ts(2,21): error TS2307: Cannot find module 'external2'.
     	                   ~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
     	                   ~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'external2'.
+!!! error TS2307: Cannot find module 'external2' or its corresponding type declarations.
     	export var a = g.square(5);
     	export var b = "foo";
     }
\ No newline at end of file
diff --git a/tests/baselines/reference/project/nestedLocalModuleWithRecursiveTypecheck/amd/nestedLocalModuleWithRecursiveTypecheck.errors.txt b/tests/baselines/reference/project/nestedLocalModuleWithRecursiveTypecheck/amd/nestedLocalModuleWithRecursiveTypecheck.errors.txt
index a8fb4fc1b2318..6c616694a3d8e 100644
--- a/tests/baselines/reference/project/nestedLocalModuleWithRecursiveTypecheck/amd/nestedLocalModuleWithRecursiveTypecheck.errors.txt
+++ b/tests/baselines/reference/project/nestedLocalModuleWithRecursiveTypecheck/amd/nestedLocalModuleWithRecursiveTypecheck.errors.txt
@@ -1,5 +1,5 @@
 test1.ts(3,23): error TS1147: Import declarations in a namespace cannot reference a module.
-test1.ts(3,23): error TS2307: Cannot find module 'test2'.
+test1.ts(3,23): error TS2307: Cannot find module 'test2' or its corresponding type declarations.
 
 
 ==== test1.ts (2 errors) ====
@@ -9,7 +9,7 @@ test1.ts(3,23): error TS2307: Cannot find module 'test2'.
                           ~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                           ~~~~~~~
-!!! error TS2307: Cannot find module 'test2'.
+!!! error TS2307: Cannot find module 'test2' or its corresponding type declarations.
     
      //console.log(foo.$);
     
diff --git a/tests/baselines/reference/project/nestedLocalModuleWithRecursiveTypecheck/node/nestedLocalModuleWithRecursiveTypecheck.errors.txt b/tests/baselines/reference/project/nestedLocalModuleWithRecursiveTypecheck/node/nestedLocalModuleWithRecursiveTypecheck.errors.txt
index a8fb4fc1b2318..6c616694a3d8e 100644
--- a/tests/baselines/reference/project/nestedLocalModuleWithRecursiveTypecheck/node/nestedLocalModuleWithRecursiveTypecheck.errors.txt
+++ b/tests/baselines/reference/project/nestedLocalModuleWithRecursiveTypecheck/node/nestedLocalModuleWithRecursiveTypecheck.errors.txt
@@ -1,5 +1,5 @@
 test1.ts(3,23): error TS1147: Import declarations in a namespace cannot reference a module.
-test1.ts(3,23): error TS2307: Cannot find module 'test2'.
+test1.ts(3,23): error TS2307: Cannot find module 'test2' or its corresponding type declarations.
 
 
 ==== test1.ts (2 errors) ====
@@ -9,7 +9,7 @@ test1.ts(3,23): error TS2307: Cannot find module 'test2'.
                           ~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                           ~~~~~~~
-!!! error TS2307: Cannot find module 'test2'.
+!!! error TS2307: Cannot find module 'test2' or its corresponding type declarations.
     
      //console.log(foo.$);
     
diff --git a/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideModule/amd/privacyCheckOnImportedModuleDeclarationsInsideModule.errors.txt b/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideModule/amd/privacyCheckOnImportedModuleDeclarationsInsideModule.errors.txt
index 0ed31c4ea38c1..ada86f611d35c 100644
--- a/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideModule/amd/privacyCheckOnImportedModuleDeclarationsInsideModule.errors.txt
+++ b/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideModule/amd/privacyCheckOnImportedModuleDeclarationsInsideModule.errors.txt
@@ -1,7 +1,7 @@
 testGlo.ts(2,39): error TS1147: Import declarations in a namespace cannot reference a module.
-testGlo.ts(2,39): error TS2307: Cannot find module 'mExported'.
+testGlo.ts(2,39): error TS2307: Cannot find module 'mExported' or its corresponding type declarations.
 testGlo.ts(21,35): error TS1147: Import declarations in a namespace cannot reference a module.
-testGlo.ts(21,35): error TS2307: Cannot find module 'mNonExported'.
+testGlo.ts(21,35): error TS2307: Cannot find module 'mNonExported' or its corresponding type declarations.
 
 
 ==== testGlo.ts (4 errors) ====
@@ -10,7 +10,7 @@ testGlo.ts(21,35): error TS2307: Cannot find module 'mNonExported'.
                                           ~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                                           ~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'mExported'.
+!!! error TS2307: Cannot find module 'mExported' or its corresponding type declarations.
         export var c1 = new mExported.me.class1;
         export function f1() {
             return new mExported.me.class1();
@@ -33,7 +33,7 @@ testGlo.ts(21,35): error TS2307: Cannot find module 'mNonExported'.
                                       ~~~~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                                       ~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'mNonExported'.
+!!! error TS2307: Cannot find module 'mNonExported' or its corresponding type declarations.
         export var c3 = new mNonExported.mne.class1;
         export function f3() {
             return new mNonExported.mne.class1();
diff --git a/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideModule/node/privacyCheckOnImportedModuleDeclarationsInsideModule.errors.txt b/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideModule/node/privacyCheckOnImportedModuleDeclarationsInsideModule.errors.txt
index 0ed31c4ea38c1..ada86f611d35c 100644
--- a/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideModule/node/privacyCheckOnImportedModuleDeclarationsInsideModule.errors.txt
+++ b/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideModule/node/privacyCheckOnImportedModuleDeclarationsInsideModule.errors.txt
@@ -1,7 +1,7 @@
 testGlo.ts(2,39): error TS1147: Import declarations in a namespace cannot reference a module.
-testGlo.ts(2,39): error TS2307: Cannot find module 'mExported'.
+testGlo.ts(2,39): error TS2307: Cannot find module 'mExported' or its corresponding type declarations.
 testGlo.ts(21,35): error TS1147: Import declarations in a namespace cannot reference a module.
-testGlo.ts(21,35): error TS2307: Cannot find module 'mNonExported'.
+testGlo.ts(21,35): error TS2307: Cannot find module 'mNonExported' or its corresponding type declarations.
 
 
 ==== testGlo.ts (4 errors) ====
@@ -10,7 +10,7 @@ testGlo.ts(21,35): error TS2307: Cannot find module 'mNonExported'.
                                           ~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                                           ~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'mExported'.
+!!! error TS2307: Cannot find module 'mExported' or its corresponding type declarations.
         export var c1 = new mExported.me.class1;
         export function f1() {
             return new mExported.me.class1();
@@ -33,7 +33,7 @@ testGlo.ts(21,35): error TS2307: Cannot find module 'mNonExported'.
                                       ~~~~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                                       ~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'mNonExported'.
+!!! error TS2307: Cannot find module 'mNonExported' or its corresponding type declarations.
         export var c3 = new mNonExported.mne.class1;
         export function f3() {
             return new mNonExported.mne.class1();
diff --git a/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideNonExportedModule/amd/privacyCheckOnImportedModuleDeclarationsInsideNonExportedModule.errors.txt b/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideNonExportedModule/amd/privacyCheckOnImportedModuleDeclarationsInsideNonExportedModule.errors.txt
index 126d5b696c1cf..dc26cfdca3fdd 100644
--- a/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideNonExportedModule/amd/privacyCheckOnImportedModuleDeclarationsInsideNonExportedModule.errors.txt
+++ b/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideNonExportedModule/amd/privacyCheckOnImportedModuleDeclarationsInsideNonExportedModule.errors.txt
@@ -1,7 +1,7 @@
 test.ts(5,39): error TS1147: Import declarations in a namespace cannot reference a module.
-test.ts(5,39): error TS2307: Cannot find module 'mExported'.
+test.ts(5,39): error TS2307: Cannot find module 'mExported' or its corresponding type declarations.
 test.ts(24,35): error TS1147: Import declarations in a namespace cannot reference a module.
-test.ts(24,35): error TS2307: Cannot find module 'mNonExported'.
+test.ts(24,35): error TS2307: Cannot find module 'mNonExported' or its corresponding type declarations.
 
 
 ==== test.ts (4 errors) ====
@@ -13,7 +13,7 @@ test.ts(24,35): error TS2307: Cannot find module 'mNonExported'.
                                           ~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                                           ~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'mExported'.
+!!! error TS2307: Cannot find module 'mExported' or its corresponding type declarations.
         export var c1 = new mExported.me.class1;
         export function f1() {
             return new mExported.me.class1();
@@ -36,7 +36,7 @@ test.ts(24,35): error TS2307: Cannot find module 'mNonExported'.
                                       ~~~~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                                       ~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'mNonExported'.
+!!! error TS2307: Cannot find module 'mNonExported' or its corresponding type declarations.
         export var c3 = new mNonExported.mne.class1;
         export function f3() {
             return new mNonExported.mne.class1();
diff --git a/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideNonExportedModule/node/privacyCheckOnImportedModuleDeclarationsInsideNonExportedModule.errors.txt b/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideNonExportedModule/node/privacyCheckOnImportedModuleDeclarationsInsideNonExportedModule.errors.txt
index 126d5b696c1cf..dc26cfdca3fdd 100644
--- a/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideNonExportedModule/node/privacyCheckOnImportedModuleDeclarationsInsideNonExportedModule.errors.txt
+++ b/tests/baselines/reference/project/privacyCheckOnImportedModuleDeclarationsInsideNonExportedModule/node/privacyCheckOnImportedModuleDeclarationsInsideNonExportedModule.errors.txt
@@ -1,7 +1,7 @@
 test.ts(5,39): error TS1147: Import declarations in a namespace cannot reference a module.
-test.ts(5,39): error TS2307: Cannot find module 'mExported'.
+test.ts(5,39): error TS2307: Cannot find module 'mExported' or its corresponding type declarations.
 test.ts(24,35): error TS1147: Import declarations in a namespace cannot reference a module.
-test.ts(24,35): error TS2307: Cannot find module 'mNonExported'.
+test.ts(24,35): error TS2307: Cannot find module 'mNonExported' or its corresponding type declarations.
 
 
 ==== test.ts (4 errors) ====
@@ -13,7 +13,7 @@ test.ts(24,35): error TS2307: Cannot find module 'mNonExported'.
                                           ~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                                           ~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'mExported'.
+!!! error TS2307: Cannot find module 'mExported' or its corresponding type declarations.
         export var c1 = new mExported.me.class1;
         export function f1() {
             return new mExported.me.class1();
@@ -36,7 +36,7 @@ test.ts(24,35): error TS2307: Cannot find module 'mNonExported'.
                                       ~~~~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                                       ~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'mNonExported'.
+!!! error TS2307: Cannot find module 'mNonExported' or its corresponding type declarations.
         export var c3 = new mNonExported.mne.class1;
         export function f3() {
             return new mNonExported.mne.class1();
diff --git a/tests/baselines/reference/project/privacyCheckOnImportedModuleImportStatementInParentModule/amd/privacyCheckOnImportedModuleImportStatementInParentModule.errors.txt b/tests/baselines/reference/project/privacyCheckOnImportedModuleImportStatementInParentModule/amd/privacyCheckOnImportedModuleImportStatementInParentModule.errors.txt
index 872e43a9b4f1d..d45bc062186e5 100644
--- a/tests/baselines/reference/project/privacyCheckOnImportedModuleImportStatementInParentModule/amd/privacyCheckOnImportedModuleImportStatementInParentModule.errors.txt
+++ b/tests/baselines/reference/project/privacyCheckOnImportedModuleImportStatementInParentModule/amd/privacyCheckOnImportedModuleImportStatementInParentModule.errors.txt
@@ -1,7 +1,7 @@
 test.ts(2,39): error TS1147: Import declarations in a namespace cannot reference a module.
-test.ts(2,39): error TS2307: Cannot find module 'mExported'.
+test.ts(2,39): error TS2307: Cannot find module 'mExported' or its corresponding type declarations.
 test.ts(42,35): error TS1147: Import declarations in a namespace cannot reference a module.
-test.ts(42,35): error TS2307: Cannot find module 'mNonExported'.
+test.ts(42,35): error TS2307: Cannot find module 'mNonExported' or its corresponding type declarations.
 
 
 ==== test.ts (4 errors) ====
@@ -10,7 +10,7 @@ test.ts(42,35): error TS2307: Cannot find module 'mNonExported'.
                                           ~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                                           ~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'mExported'.
+!!! error TS2307: Cannot find module 'mExported' or its corresponding type declarations.
     
         module Internal_M1 {
             export var c1 = new mExported.me.class1;
@@ -54,7 +54,7 @@ test.ts(42,35): error TS2307: Cannot find module 'mNonExported'.
                                       ~~~~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                                       ~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'mNonExported'.
+!!! error TS2307: Cannot find module 'mNonExported' or its corresponding type declarations.
         module Internal_M3 {
             export var c3 = new mNonExported.mne.class1;
             export function f3() {
diff --git a/tests/baselines/reference/project/privacyCheckOnImportedModuleImportStatementInParentModule/node/privacyCheckOnImportedModuleImportStatementInParentModule.errors.txt b/tests/baselines/reference/project/privacyCheckOnImportedModuleImportStatementInParentModule/node/privacyCheckOnImportedModuleImportStatementInParentModule.errors.txt
index 872e43a9b4f1d..d45bc062186e5 100644
--- a/tests/baselines/reference/project/privacyCheckOnImportedModuleImportStatementInParentModule/node/privacyCheckOnImportedModuleImportStatementInParentModule.errors.txt
+++ b/tests/baselines/reference/project/privacyCheckOnImportedModuleImportStatementInParentModule/node/privacyCheckOnImportedModuleImportStatementInParentModule.errors.txt
@@ -1,7 +1,7 @@
 test.ts(2,39): error TS1147: Import declarations in a namespace cannot reference a module.
-test.ts(2,39): error TS2307: Cannot find module 'mExported'.
+test.ts(2,39): error TS2307: Cannot find module 'mExported' or its corresponding type declarations.
 test.ts(42,35): error TS1147: Import declarations in a namespace cannot reference a module.
-test.ts(42,35): error TS2307: Cannot find module 'mNonExported'.
+test.ts(42,35): error TS2307: Cannot find module 'mNonExported' or its corresponding type declarations.
 
 
 ==== test.ts (4 errors) ====
@@ -10,7 +10,7 @@ test.ts(42,35): error TS2307: Cannot find module 'mNonExported'.
                                           ~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                                           ~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'mExported'.
+!!! error TS2307: Cannot find module 'mExported' or its corresponding type declarations.
     
         module Internal_M1 {
             export var c1 = new mExported.me.class1;
@@ -54,7 +54,7 @@ test.ts(42,35): error TS2307: Cannot find module 'mNonExported'.
                                       ~~~~~~~~~~~~~~
 !!! error TS1147: Import declarations in a namespace cannot reference a module.
                                       ~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module 'mNonExported'.
+!!! error TS2307: Cannot find module 'mNonExported' or its corresponding type declarations.
         module Internal_M3 {
             export var c3 = new mNonExported.mne.class1;
             export function f3() {
diff --git a/tests/baselines/reference/propertyAssignmentOnUnresolvedImportedSymbol.errors.txt b/tests/baselines/reference/propertyAssignmentOnUnresolvedImportedSymbol.errors.txt
index 447285b8328ef..28cdc25e75709 100644
--- a/tests/baselines/reference/propertyAssignmentOnUnresolvedImportedSymbol.errors.txt
+++ b/tests/baselines/reference/propertyAssignmentOnUnresolvedImportedSymbol.errors.txt
@@ -1,10 +1,10 @@
-tests/cases/conformance/salsa/bug28576.js(1,15): error TS2307: Cannot find module 'arglebaz'.
+tests/cases/conformance/salsa/bug28576.js(1,15): error TS2307: Cannot find module 'arglebaz' or its corresponding type declarations.
 
 
 ==== tests/cases/conformance/salsa/bug28576.js (1 errors) ====
     import x from 'arglebaz'
                   ~~~~~~~~~~
-!!! error TS2307: Cannot find module 'arglebaz'.
+!!! error TS2307: Cannot find module 'arglebaz' or its corresponding type declarations.
     {
         x.bar = 1
     }
diff --git a/tests/baselines/reference/relativeNamesInClassicResolution.errors.txt b/tests/baselines/reference/relativeNamesInClassicResolution.errors.txt
index 228c395cf119a..518063bc9e43f 100644
--- a/tests/baselines/reference/relativeNamesInClassicResolution.errors.txt
+++ b/tests/baselines/reference/relativeNamesInClassicResolution.errors.txt
@@ -1,10 +1,10 @@
-tests/cases/compiler/somefolder/a.ts(1,17): error TS2307: Cannot find module './b'.
+tests/cases/compiler/somefolder/a.ts(1,17): error TS2307: Cannot find module './b' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/somefolder/a.ts (1 errors) ====
     import {x} from "./b"
                     ~~~~~
-!!! error TS2307: Cannot find module './b'.
+!!! error TS2307: Cannot find module './b' or its corresponding type declarations.
     
 ==== tests/cases/compiler/b.ts (0 errors) ====
     export let x = 1;
\ No newline at end of file
diff --git a/tests/baselines/reference/relativePathMustResolve.errors.txt b/tests/baselines/reference/relativePathMustResolve.errors.txt
index 1ff89a74623ca..90b59e8c15b15 100644
--- a/tests/baselines/reference/relativePathMustResolve.errors.txt
+++ b/tests/baselines/reference/relativePathMustResolve.errors.txt
@@ -1,10 +1,10 @@
-tests/cases/conformance/externalModules/foo_1.ts(1,22): error TS2307: Cannot find module './test/foo'.
+tests/cases/conformance/externalModules/foo_1.ts(1,22): error TS2307: Cannot find module './test/foo' or its corresponding type declarations.
 
 
 ==== tests/cases/conformance/externalModules/foo_1.ts (1 errors) ====
     import foo = require('./test/foo');
                          ~~~~~~~~~~~~
-!!! error TS2307: Cannot find module './test/foo'.
+!!! error TS2307: Cannot find module './test/foo' or its corresponding type declarations.
     var z = foo.x + 10;
     
 ==== tests/cases/conformance/externalModules/foo_0.ts (0 errors) ====
diff --git a/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.errors.txt b/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.errors.txt
index 13660f8b83648..2872d92a2839a 100644
--- a/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.errors.txt
+++ b/tests/baselines/reference/requireOfJsonFileNonRelativeWithoutExtension.errors.txt
@@ -1,14 +1,14 @@
-/src/projects/file1.ts(1,20): error TS2307: Cannot find module 'd.json'.
-/src/projects/file1.ts(2,20): error TS2307: Cannot find module 'e'.
+/src/projects/file1.ts(1,20): error TS2307: Cannot find module 'd.json' or its corresponding type declarations.
+/src/projects/file1.ts(2,20): error TS2307: Cannot find module 'e' or its corresponding type declarations.
 
 
 ==== /src/projects/file1.ts (2 errors) ====
     import d = require("d.json"); // Should fail
                        ~~~~~~~~
-!!! error TS2307: Cannot find module 'd.json'.
+!!! error TS2307: Cannot find module 'd.json' or its corresponding type declarations.
     import e = require("e"); // Should fail
                        ~~~
-!!! error TS2307: Cannot find module 'e'.
+!!! error TS2307: Cannot find module 'e' or its corresponding type declarations.
     
 ==== /src/projects/node_modules/b.json (0 errors) ====
     {
diff --git a/tests/baselines/reference/requireOfJsonFileWithAmd.errors.txt b/tests/baselines/reference/requireOfJsonFileWithAmd.errors.txt
index 2c43e1d530179..258d925a70dfc 100644
--- a/tests/baselines/reference/requireOfJsonFileWithAmd.errors.txt
+++ b/tests/baselines/reference/requireOfJsonFileWithAmd.errors.txt
@@ -1,17 +1,17 @@
 error TS5070: Option '--resolveJsonModule' cannot be specified without 'node' module resolution strategy.
-tests/cases/compiler/file1.ts(1,21): error TS2307: Cannot find module './b'.
-tests/cases/compiler/file1.ts(3,21): error TS2307: Cannot find module './b.json'.
+tests/cases/compiler/file1.ts(1,21): error TS2307: Cannot find module './b' or its corresponding type declarations.
+tests/cases/compiler/file1.ts(3,21): error TS2307: Cannot find module './b.json' or its corresponding type declarations.
 
 
 !!! error TS5070: Option '--resolveJsonModule' cannot be specified without 'node' module resolution strategy.
 ==== tests/cases/compiler/file1.ts (2 errors) ====
     import b1 = require('./b');
                         ~~~~~
-!!! error TS2307: Cannot find module './b'.
+!!! error TS2307: Cannot find module './b' or its corresponding type declarations.
     let x = b1.a;
     import b2 = require('./b.json');
                         ~~~~~~~~~~
-!!! error TS2307: Cannot find module './b.json'.
+!!! error TS2307: Cannot find module './b.json' or its corresponding type declarations.
     if (x) {
         let b = b2.b;
         x = (b1.b === b);
diff --git a/tests/baselines/reference/requireOfJsonFileWithModuleEmitNone.errors.txt b/tests/baselines/reference/requireOfJsonFileWithModuleEmitNone.errors.txt
index 1a92da0939559..1ec53ee17f956 100644
--- a/tests/baselines/reference/requireOfJsonFileWithModuleEmitNone.errors.txt
+++ b/tests/baselines/reference/requireOfJsonFileWithModuleEmitNone.errors.txt
@@ -1,6 +1,6 @@
 error TS5070: Option '--resolveJsonModule' cannot be specified without 'node' module resolution strategy.
 tests/cases/compiler/file1.ts(1,1): error TS1148: Cannot use imports, exports, or module augmentations when '--module' is 'none'.
-tests/cases/compiler/file1.ts(1,20): error TS2307: Cannot find module './b.json'.
+tests/cases/compiler/file1.ts(1,20): error TS2307: Cannot find module './b.json' or its corresponding type declarations.
 
 
 !!! error TS5070: Option '--resolveJsonModule' cannot be specified without 'node' module resolution strategy.
@@ -9,7 +9,7 @@ tests/cases/compiler/file1.ts(1,20): error TS2307: Cannot find module './b.json'
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS1148: Cannot use imports, exports, or module augmentations when '--module' is 'none'.
                        ~~~~~~~~~~
-!!! error TS2307: Cannot find module './b.json'.
+!!! error TS2307: Cannot find module './b.json' or its corresponding type declarations.
     
 ==== tests/cases/compiler/b.json (0 errors) ====
     {
diff --git a/tests/baselines/reference/requireOfJsonFileWithoutExtension.errors.txt b/tests/baselines/reference/requireOfJsonFileWithoutExtension.errors.txt
index 799b78c26eec8..a2ceaa0fa4cdf 100644
--- a/tests/baselines/reference/requireOfJsonFileWithoutExtension.errors.txt
+++ b/tests/baselines/reference/requireOfJsonFileWithoutExtension.errors.txt
@@ -1,10 +1,10 @@
-tests/cases/compiler/file1.ts(1,21): error TS2307: Cannot find module './b'.
+tests/cases/compiler/file1.ts(1,21): error TS2307: Cannot find module './b' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/file1.ts (1 errors) ====
     import b1 = require('./b'); // This should not resolve
                         ~~~~~
-!!! error TS2307: Cannot find module './b'.
+!!! error TS2307: Cannot find module './b' or its corresponding type declarations.
     let x = b1.a;
     import b2 = require('./b.json');
     if (x) {
diff --git a/tests/baselines/reference/shorthand-property-es5-es6.errors.txt b/tests/baselines/reference/shorthand-property-es5-es6.errors.txt
index 650263a08c4e4..31b5eeaadf5e6 100644
--- a/tests/baselines/reference/shorthand-property-es5-es6.errors.txt
+++ b/tests/baselines/reference/shorthand-property-es5-es6.errors.txt
@@ -1,10 +1,10 @@
-tests/cases/compiler/test.ts(1,19): error TS2307: Cannot find module './foo'.
+tests/cases/compiler/test.ts(1,19): error TS2307: Cannot find module './foo' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/test.ts (1 errors) ====
     import {foo} from './foo';
                       ~~~~~~~
-!!! error TS2307: Cannot find module './foo'.
+!!! error TS2307: Cannot find module './foo' or its corresponding type declarations.
     const baz = 42;
     const bar = { foo, baz };
     
\ No newline at end of file
diff --git a/tests/baselines/reference/shorthand-property-es6-amd.errors.txt b/tests/baselines/reference/shorthand-property-es6-amd.errors.txt
index 650263a08c4e4..31b5eeaadf5e6 100644
--- a/tests/baselines/reference/shorthand-property-es6-amd.errors.txt
+++ b/tests/baselines/reference/shorthand-property-es6-amd.errors.txt
@@ -1,10 +1,10 @@
-tests/cases/compiler/test.ts(1,19): error TS2307: Cannot find module './foo'.
+tests/cases/compiler/test.ts(1,19): error TS2307: Cannot find module './foo' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/test.ts (1 errors) ====
     import {foo} from './foo';
                       ~~~~~~~
-!!! error TS2307: Cannot find module './foo'.
+!!! error TS2307: Cannot find module './foo' or its corresponding type declarations.
     const baz = 42;
     const bar = { foo, baz };
     
\ No newline at end of file
diff --git a/tests/baselines/reference/shorthand-property-es6-es6.errors.txt b/tests/baselines/reference/shorthand-property-es6-es6.errors.txt
index 650263a08c4e4..31b5eeaadf5e6 100644
--- a/tests/baselines/reference/shorthand-property-es6-es6.errors.txt
+++ b/tests/baselines/reference/shorthand-property-es6-es6.errors.txt
@@ -1,10 +1,10 @@
-tests/cases/compiler/test.ts(1,19): error TS2307: Cannot find module './foo'.
+tests/cases/compiler/test.ts(1,19): error TS2307: Cannot find module './foo' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/test.ts (1 errors) ====
     import {foo} from './foo';
                       ~~~~~~~
-!!! error TS2307: Cannot find module './foo'.
+!!! error TS2307: Cannot find module './foo' or its corresponding type declarations.
     const baz = 42;
     const bar = { foo, baz };
     
\ No newline at end of file
diff --git a/tests/baselines/reference/shorthandPropertyAssignmentInES6Module.errors.txt b/tests/baselines/reference/shorthandPropertyAssignmentInES6Module.errors.txt
index 22522208ea890..ada28aac1e62d 100644
--- a/tests/baselines/reference/shorthandPropertyAssignmentInES6Module.errors.txt
+++ b/tests/baselines/reference/shorthandPropertyAssignmentInES6Module.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/test.ts(2,19): error TS2307: Cannot find module './missingModule'.
+tests/cases/compiler/test.ts(2,19): error TS2307: Cannot find module './missingModule' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/existingModule.ts (0 errors) ====
@@ -8,7 +8,7 @@ tests/cases/compiler/test.ts(2,19): error TS2307: Cannot find module './missingM
     import {x} from './existingModule';
     import {foo} from './missingModule';
                       ~~~~~~~~~~~~~~~~~
-!!! error TS2307: Cannot find module './missingModule'.
+!!! error TS2307: Cannot find module './missingModule' or its corresponding type declarations.
     
     declare function use(a: any): void;
     
diff --git a/tests/baselines/reference/strictModeReservedWordInImportEqualDeclaration.errors.txt b/tests/baselines/reference/strictModeReservedWordInImportEqualDeclaration.errors.txt
index bde4ec862bd35..cf8455e93a5c1 100644
--- a/tests/baselines/reference/strictModeReservedWordInImportEqualDeclaration.errors.txt
+++ b/tests/baselines/reference/strictModeReservedWordInImportEqualDeclaration.errors.txt
@@ -1,5 +1,5 @@
 tests/cases/compiler/strictModeReservedWordInImportEqualDeclaration.ts(2,8): error TS1214: Identifier expected. 'public' is a reserved word in strict mode. Modules are automatically in strict mode.
-tests/cases/compiler/strictModeReservedWordInImportEqualDeclaration.ts(2,25): error TS2307: Cannot find module '1'.
+tests/cases/compiler/strictModeReservedWordInImportEqualDeclaration.ts(2,25): error TS2307: Cannot find module '1' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/strictModeReservedWordInImportEqualDeclaration.ts (2 errors) ====
@@ -8,4 +8,4 @@ tests/cases/compiler/strictModeReservedWordInImportEqualDeclaration.ts(2,25): er
            ~~~~~~
 !!! error TS1214: Identifier expected. 'public' is a reserved word in strict mode. Modules are automatically in strict mode.
                             ~~~
-!!! error TS2307: Cannot find module '1'.
\ No newline at end of file
+!!! error TS2307: Cannot find module '1' or its corresponding type declarations.
\ No newline at end of file
diff --git a/tests/baselines/reference/strictModeWordInImportDeclaration.errors.txt b/tests/baselines/reference/strictModeWordInImportDeclaration.errors.txt
index b6e20cfc188ae..351de7cf7e356 100644
--- a/tests/baselines/reference/strictModeWordInImportDeclaration.errors.txt
+++ b/tests/baselines/reference/strictModeWordInImportDeclaration.errors.txt
@@ -1,9 +1,9 @@
 tests/cases/compiler/strictModeWordInImportDeclaration.ts(2,13): error TS1214: Identifier expected. 'package' is a reserved word in strict mode. Modules are automatically in strict mode.
-tests/cases/compiler/strictModeWordInImportDeclaration.ts(2,26): error TS2307: Cannot find module './1'.
+tests/cases/compiler/strictModeWordInImportDeclaration.ts(2,26): error TS2307: Cannot find module './1' or its corresponding type declarations.
 tests/cases/compiler/strictModeWordInImportDeclaration.ts(3,16): error TS1214: Identifier expected. 'private' is a reserved word in strict mode. Modules are automatically in strict mode.
-tests/cases/compiler/strictModeWordInImportDeclaration.ts(3,30): error TS2307: Cannot find module './1'.
+tests/cases/compiler/strictModeWordInImportDeclaration.ts(3,30): error TS2307: Cannot find module './1' or its corresponding type declarations.
 tests/cases/compiler/strictModeWordInImportDeclaration.ts(4,8): error TS1214: Identifier expected. 'public' is a reserved word in strict mode. Modules are automatically in strict mode.
-tests/cases/compiler/strictModeWordInImportDeclaration.ts(4,20): error TS2307: Cannot find module './1'.
+tests/cases/compiler/strictModeWordInImportDeclaration.ts(4,20): error TS2307: Cannot find module './1' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/strictModeWordInImportDeclaration.ts (6 errors) ====
@@ -12,14 +12,14 @@ tests/cases/compiler/strictModeWordInImportDeclaration.ts(4,20): error TS2307: C
                 ~~~~~~~
 !!! error TS1214: Identifier expected. 'package' is a reserved word in strict mode. Modules are automatically in strict mode.
                              ~~~~~
-!!! error TS2307: Cannot find module './1'.
+!!! error TS2307: Cannot find module './1' or its corresponding type declarations.
     import {foo as private} from "./1"
                    ~~~~~~~
 !!! error TS1214: Identifier expected. 'private' is a reserved word in strict mode. Modules are automatically in strict mode.
                                  ~~~~~
-!!! error TS2307: Cannot find module './1'.
+!!! error TS2307: Cannot find module './1' or its corresponding type declarations.
     import public from "./1"
            ~~~~~~
 !!! error TS1214: Identifier expected. 'public' is a reserved word in strict mode. Modules are automatically in strict mode.
                        ~~~~~
-!!! error TS2307: Cannot find module './1'.
\ No newline at end of file
+!!! error TS2307: Cannot find module './1' or its corresponding type declarations.
\ No newline at end of file
diff --git a/tests/baselines/reference/systemModule10.errors.txt b/tests/baselines/reference/systemModule10.errors.txt
index e1548b30f9087..539f17784587e 100644
--- a/tests/baselines/reference/systemModule10.errors.txt
+++ b/tests/baselines/reference/systemModule10.errors.txt
@@ -1,14 +1,14 @@
-tests/cases/compiler/systemModule10.ts(1,20): error TS2307: Cannot find module 'file1'.
-tests/cases/compiler/systemModule10.ts(2,21): error TS2307: Cannot find module 'file2'.
+tests/cases/compiler/systemModule10.ts(1,20): error TS2307: Cannot find module 'file1' or its corresponding type declarations.
+tests/cases/compiler/systemModule10.ts(2,21): error TS2307: Cannot find module 'file2' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/systemModule10.ts (2 errors) ====
     import n, {x} from 'file1'
                        ~~~~~~~
-!!! error TS2307: Cannot find module 'file1'.
+!!! error TS2307: Cannot find module 'file1' or its corresponding type declarations.
     import n2 = require('file2');
                         ~~~~~~~
-!!! error TS2307: Cannot find module 'file2'.
+!!! error TS2307: Cannot find module 'file2' or its corresponding type declarations.
     export {x}
     export {x as y}
     export {n}
diff --git a/tests/baselines/reference/systemModule10_ES5.errors.txt b/tests/baselines/reference/systemModule10_ES5.errors.txt
index 4a22dba31cde4..5e5e47ddbbe4a 100644
--- a/tests/baselines/reference/systemModule10_ES5.errors.txt
+++ b/tests/baselines/reference/systemModule10_ES5.errors.txt
@@ -1,14 +1,14 @@
-tests/cases/compiler/systemModule10_ES5.ts(1,20): error TS2307: Cannot find module 'file1'.
-tests/cases/compiler/systemModule10_ES5.ts(2,21): error TS2307: Cannot find module 'file2'.
+tests/cases/compiler/systemModule10_ES5.ts(1,20): error TS2307: Cannot find module 'file1' or its corresponding type declarations.
+tests/cases/compiler/systemModule10_ES5.ts(2,21): error TS2307: Cannot find module 'file2' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/systemModule10_ES5.ts (2 errors) ====
     import n, {x} from 'file1'
                        ~~~~~~~
-!!! error TS2307: Cannot find module 'file1'.
+!!! error TS2307: Cannot find module 'file1' or its corresponding type declarations.
     import n2 = require('file2');
                         ~~~~~~~
-!!! error TS2307: Cannot find module 'file2'.
+!!! error TS2307: Cannot find module 'file2' or its corresponding type declarations.
     export {x}
     export {x as y}
     export {n}
diff --git a/tests/baselines/reference/systemModule11.errors.txt b/tests/baselines/reference/systemModule11.errors.txt
index 46a47cc9a938a..649b764bfcc35 100644
--- a/tests/baselines/reference/systemModule11.errors.txt
+++ b/tests/baselines/reference/systemModule11.errors.txt
@@ -1,9 +1,9 @@
-tests/cases/compiler/file1.ts(6,15): error TS2307: Cannot find module 'bar'.
-tests/cases/compiler/file2.ts(6,15): error TS2307: Cannot find module 'bar'.
-tests/cases/compiler/file3.ts(1,25): error TS2307: Cannot find module 'a'.
-tests/cases/compiler/file3.ts(3,15): error TS2307: Cannot find module 'bar'.
-tests/cases/compiler/file4.ts(8,27): error TS2307: Cannot find module 'a'.
-tests/cases/compiler/file5.ts(2,15): error TS2307: Cannot find module 'a'.
+tests/cases/compiler/file1.ts(6,15): error TS2307: Cannot find module 'bar' or its corresponding type declarations.
+tests/cases/compiler/file2.ts(6,15): error TS2307: Cannot find module 'bar' or its corresponding type declarations.
+tests/cases/compiler/file3.ts(1,25): error TS2307: Cannot find module 'a' or its corresponding type declarations.
+tests/cases/compiler/file3.ts(3,15): error TS2307: Cannot find module 'bar' or its corresponding type declarations.
+tests/cases/compiler/file4.ts(8,27): error TS2307: Cannot find module 'a' or its corresponding type declarations.
+tests/cases/compiler/file5.ts(2,15): error TS2307: Cannot find module 'a' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/file1.ts (1 errors) ====
@@ -14,7 +14,7 @@ tests/cases/compiler/file5.ts(2,15): error TS2307: Cannot find module 'a'.
     export function foo() {}
     export * from 'bar';
                   ~~~~~
-!!! error TS2307: Cannot find module 'bar'.
+!!! error TS2307: Cannot find module 'bar' or its corresponding type declarations.
     
 ==== tests/cases/compiler/file2.ts (1 errors) ====
     var x;
@@ -24,16 +24,16 @@ tests/cases/compiler/file5.ts(2,15): error TS2307: Cannot find module 'a'.
     
     export * from 'bar';
                   ~~~~~
-!!! error TS2307: Cannot find module 'bar'.
+!!! error TS2307: Cannot find module 'bar' or its corresponding type declarations.
     
 ==== tests/cases/compiler/file3.ts (2 errors) ====
     export {x, y as z} from 'a';
                             ~~~
-!!! error TS2307: Cannot find module 'a'.
+!!! error TS2307: Cannot find module 'a' or its corresponding type declarations.
     export default function foo() {}
     export * from 'bar';
                   ~~~~~
-!!! error TS2307: Cannot find module 'bar'.
+!!! error TS2307: Cannot find module 'bar' or its corresponding type declarations.
     
 ==== tests/cases/compiler/file4.ts (1 errors) ====
     export var x;
@@ -45,10 +45,10 @@ tests/cases/compiler/file5.ts(2,15): error TS2307: Cannot find module 'a'.
     
     export {s, s1 as s2} from 'a'
                               ~~~
-!!! error TS2307: Cannot find module 'a'.
+!!! error TS2307: Cannot find module 'a' or its corresponding type declarations.
     
 ==== tests/cases/compiler/file5.ts (1 errors) ====
     function foo() {}
     export * from 'a';
                   ~~~
-!!! error TS2307: Cannot find module 'a'.
\ No newline at end of file
+!!! error TS2307: Cannot find module 'a' or its corresponding type declarations.
\ No newline at end of file
diff --git a/tests/baselines/reference/systemModule12.errors.txt b/tests/baselines/reference/systemModule12.errors.txt
index 57de4e1f9a5c9..0563f37b16acb 100644
--- a/tests/baselines/reference/systemModule12.errors.txt
+++ b/tests/baselines/reference/systemModule12.errors.txt
@@ -1,9 +1,9 @@
-tests/cases/compiler/systemModule12.ts(2,15): error TS2307: Cannot find module 'file1'.
+tests/cases/compiler/systemModule12.ts(2,15): error TS2307: Cannot find module 'file1' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/systemModule12.ts (1 errors) ====
     ///<amd-module name='NamedModule'/>
     import n from 'file1'
                   ~~~~~~~
-!!! error TS2307: Cannot find module 'file1'.
+!!! error TS2307: Cannot find module 'file1' or its corresponding type declarations.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/systemModule14.errors.txt b/tests/baselines/reference/systemModule14.errors.txt
index a1555fdab321b..8b6c0852f27ac 100644
--- a/tests/baselines/reference/systemModule14.errors.txt
+++ b/tests/baselines/reference/systemModule14.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/systemModule14.ts(5,17): error TS2307: Cannot find module 'foo'.
+tests/cases/compiler/systemModule14.ts(5,17): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/systemModule14.ts (1 errors) ====
@@ -8,7 +8,7 @@ tests/cases/compiler/systemModule14.ts(5,17): error TS2307: Cannot find module '
     
     import {a} from "foo";
                     ~~~~~
-!!! error TS2307: Cannot find module 'foo'.
+!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
     export {foo}
     
     var x = 1;
diff --git a/tests/baselines/reference/systemModule16.errors.txt b/tests/baselines/reference/systemModule16.errors.txt
index 6e65f7e31a1e1..6f5bf93daacb9 100644
--- a/tests/baselines/reference/systemModule16.errors.txt
+++ b/tests/baselines/reference/systemModule16.errors.txt
@@ -1,9 +1,9 @@
-tests/cases/compiler/systemModule16.ts(1,20): error TS2307: Cannot find module 'foo'.
-tests/cases/compiler/systemModule16.ts(2,20): error TS2307: Cannot find module 'bar'.
-tests/cases/compiler/systemModule16.ts(3,15): error TS2307: Cannot find module 'foo'.
-tests/cases/compiler/systemModule16.ts(4,15): error TS2307: Cannot find module 'bar'.
-tests/cases/compiler/systemModule16.ts(7,32): error TS2307: Cannot find module 'foo'.
-tests/cases/compiler/systemModule16.ts(8,32): error TS2307: Cannot find module 'bar'.
+tests/cases/compiler/systemModule16.ts(1,20): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
+tests/cases/compiler/systemModule16.ts(2,20): error TS2307: Cannot find module 'bar' or its corresponding type declarations.
+tests/cases/compiler/systemModule16.ts(3,15): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
+tests/cases/compiler/systemModule16.ts(4,15): error TS2307: Cannot find module 'bar' or its corresponding type declarations.
+tests/cases/compiler/systemModule16.ts(7,32): error TS2307: Cannot find module 'foo' or its corresponding type declarations.
+tests/cases/compiler/systemModule16.ts(8,32): error TS2307: Cannot find module 'bar' or its corresponding type declarations.
 tests/cases/compiler/systemModule16.ts(10,1): error TS2695: Left side of comma operator is unused and has no side effects.
 tests/cases/compiler/systemModule16.ts(10,1): error TS2695: Left side of comma operator is unused and has no side effects.
 tests/cases/compiler/systemModule16.ts(10,1): error TS2695: Left side of comma operator is unused and has no side effects.
@@ -13,24 +13,24 @@ tests/cases/compiler/systemModule16.ts(10,1): error TS2695: Left side of comma o
 ==== tests/cases/compiler/systemModule16.ts (10 errors) ====
     import * as x from "foo";
                        ~~~~~
-!!! error TS2307: Cannot find module 'foo'.
+!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
     import * as y from "bar";
                        ~~~~~
-!!! error TS2307: Cannot find module 'bar'.
+!!! error TS2307: Cannot find module 'bar' or its corresponding type declarations.
     export * from "foo";
                   ~~~~~
-!!! error TS2307: Cannot find module 'foo'.
+!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
     export * from "bar"
                   ~~~~~
-!!! error TS2307: Cannot find module 'bar'.
+!!! error TS2307: Cannot find module 'bar' or its corresponding type declarations.
     export {x}
     export {y}
     import {a1, b1, c1 as d1} from "foo";
                                    ~~~~~
-!!! error TS2307: Cannot find module 'foo'.
+!!! error TS2307: Cannot find module 'foo' or its corresponding type declarations.
     export {a2, b2, c2 as d2} from "bar";
                                    ~~~~~
-!!! error TS2307: Cannot find module 'bar'.
+!!! error TS2307: Cannot find module 'bar' or its corresponding type declarations.
     
     x,y,a1,b1,d1;
     ~
diff --git a/tests/baselines/reference/systemModule9.errors.txt b/tests/baselines/reference/systemModule9.errors.txt
index bedcc561058f2..c38c85b1798c1 100644
--- a/tests/baselines/reference/systemModule9.errors.txt
+++ b/tests/baselines/reference/systemModule9.errors.txt
@@ -1,28 +1,28 @@
-tests/cases/compiler/systemModule9.ts(1,21): error TS2307: Cannot find module 'file1'.
-tests/cases/compiler/systemModule9.ts(2,25): error TS2307: Cannot find module 'file2'.
-tests/cases/compiler/systemModule9.ts(3,15): error TS2307: Cannot find module 'file3'.
-tests/cases/compiler/systemModule9.ts(5,25): error TS2307: Cannot find module 'file5'.
-tests/cases/compiler/systemModule9.ts(6,22): error TS2307: Cannot find module 'file6'.
-tests/cases/compiler/systemModule9.ts(16,15): error TS2307: Cannot find module 'file7'.
+tests/cases/compiler/systemModule9.ts(1,21): error TS2307: Cannot find module 'file1' or its corresponding type declarations.
+tests/cases/compiler/systemModule9.ts(2,25): error TS2307: Cannot find module 'file2' or its corresponding type declarations.
+tests/cases/compiler/systemModule9.ts(3,15): error TS2307: Cannot find module 'file3' or its corresponding type declarations.
+tests/cases/compiler/systemModule9.ts(5,25): error TS2307: Cannot find module 'file5' or its corresponding type declarations.
+tests/cases/compiler/systemModule9.ts(6,22): error TS2307: Cannot find module 'file6' or its corresponding type declarations.
+tests/cases/compiler/systemModule9.ts(16,15): error TS2307: Cannot find module 'file7' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/systemModule9.ts (6 errors) ====
     import * as ns from 'file1';
                         ~~~~~~~
-!!! error TS2307: Cannot find module 'file1'.
+!!! error TS2307: Cannot find module 'file1' or its corresponding type declarations.
     import {a, b as c} from 'file2';
                             ~~~~~~~
-!!! error TS2307: Cannot find module 'file2'.
+!!! error TS2307: Cannot find module 'file2' or its corresponding type declarations.
     import d from 'file3'
                   ~~~~~~~
-!!! error TS2307: Cannot find module 'file3'.
+!!! error TS2307: Cannot find module 'file3' or its corresponding type declarations.
     import 'file4'
     import e, * as ns2 from 'file5';
                             ~~~~~~~
-!!! error TS2307: Cannot find module 'file5'.
+!!! error TS2307: Cannot find module 'file5' or its corresponding type declarations.
     import ns3 = require('file6');
                          ~~~~~~~
-!!! error TS2307: Cannot find module 'file6'.
+!!! error TS2307: Cannot find module 'file6' or its corresponding type declarations.
     
     ns.f();
     a();
@@ -34,7 +34,7 @@ tests/cases/compiler/systemModule9.ts(16,15): error TS2307: Cannot find module '
     
     export * from 'file7';
                   ~~~~~~~
-!!! error TS2307: Cannot find module 'file7'.
+!!! error TS2307: Cannot find module 'file7' or its corresponding type declarations.
     
     var x, y = true;
     export {x};
diff --git a/tests/baselines/reference/topLevelFileModuleMissing.errors.txt b/tests/baselines/reference/topLevelFileModuleMissing.errors.txt
index 7642bfd86a2ab..e440eb76253d7 100644
--- a/tests/baselines/reference/topLevelFileModuleMissing.errors.txt
+++ b/tests/baselines/reference/topLevelFileModuleMissing.errors.txt
@@ -1,10 +1,10 @@
-tests/cases/conformance/externalModules/foo_1.ts(1,22): error TS2307: Cannot find module 'vs/foo'.
+tests/cases/conformance/externalModules/foo_1.ts(1,22): error TS2307: Cannot find module 'vs/foo' or its corresponding type declarations.
 
 
 ==== tests/cases/conformance/externalModules/foo_1.ts (1 errors) ====
     import foo = require("vs/foo");
                          ~~~~~~~~
-!!! error TS2307: Cannot find module 'vs/foo'.
+!!! error TS2307: Cannot find module 'vs/foo' or its corresponding type declarations.
     var z = foo.x + 10;
     
 ==== tests/cases/conformance/externalModules/vs/foo_0.ts (0 errors) ====
diff --git a/tests/baselines/reference/tsbuild/transitiveReferences/initial-build/reports-error-about-module-not-found-with-node-resolution-with-external-module-name.js b/tests/baselines/reference/tsbuild/transitiveReferences/initial-build/reports-error-about-module-not-found-with-node-resolution-with-external-module-name.js
index c2c25e054e7c6..343d896fcc87c 100644
--- a/tests/baselines/reference/tsbuild/transitiveReferences/initial-build/reports-error-about-module-not-found-with-node-resolution-with-external-module-name.js
+++ b/tests/baselines/reference/tsbuild/transitiveReferences/initial-build/reports-error-about-module-not-found-with-node-resolution-with-external-module-name.js
@@ -2,7 +2,7 @@
 /lib/tsc --b /src/tsconfig.c.json --listFiles
 /lib/lib.d.ts
 /src/a.ts
-src/b.ts:1:17 - error TS2307: Cannot find module 'a'.
+src/b.ts:1:17 - error TS2307: Cannot find module 'a' or its corresponding type declarations.
 
 1 import {A} from 'a';
                   ~~~
diff --git a/tests/baselines/reference/tscWatch/programUpdates/add-the-missing-module-file-for-inferred-project-should-remove-the-module-not-found-error.js b/tests/baselines/reference/tscWatch/programUpdates/add-the-missing-module-file-for-inferred-project-should-remove-the-module-not-found-error.js
index 5189293311d59..28536787baa6f 100644
--- a/tests/baselines/reference/tscWatch/programUpdates/add-the-missing-module-file-for-inferred-project-should-remove-the-module-not-found-error.js
+++ b/tests/baselines/reference/tscWatch/programUpdates/add-the-missing-module-file-for-inferred-project-should-remove-the-module-not-found-error.js
@@ -28,7 +28,7 @@ Output::
 [12:00:13 AM] Starting compilation in watch mode...
 
 
-a/b/file1.ts:1:20 - error TS2307: Cannot find module './moduleFile'.
+a/b/file1.ts:1:20 - error TS2307: Cannot find module './moduleFile' or its corresponding type declarations.
 
 1 import * as T from "./moduleFile"; T.bar();
                      ~~~~~~~~~~~~~~
diff --git a/tests/baselines/reference/tscWatch/programUpdates/rename-a-module-file-and-rename-back-should-restore-the-states-for-configured-projects.js b/tests/baselines/reference/tscWatch/programUpdates/rename-a-module-file-and-rename-back-should-restore-the-states-for-configured-projects.js
index 6483755722f58..0a26775551849 100644
--- a/tests/baselines/reference/tscWatch/programUpdates/rename-a-module-file-and-rename-back-should-restore-the-states-for-configured-projects.js
+++ b/tests/baselines/reference/tscWatch/programUpdates/rename-a-module-file-and-rename-back-should-restore-the-states-for-configured-projects.js
@@ -102,7 +102,7 @@ Output::
 [12:00:27 AM] File change detected. Starting incremental compilation...
 
 
-a/b/file1.ts:1:20 - error TS2307: Cannot find module './moduleFile'.
+a/b/file1.ts:1:20 - error TS2307: Cannot find module './moduleFile' or its corresponding type declarations.
 
 1 import * as T from "./moduleFile"; T.bar();
                      ~~~~~~~~~~~~~~
diff --git a/tests/baselines/reference/tscWatch/programUpdates/rename-a-module-file-and-rename-back-should-restore-the-states-for-inferred-projects.js b/tests/baselines/reference/tscWatch/programUpdates/rename-a-module-file-and-rename-back-should-restore-the-states-for-inferred-projects.js
index 4d935309ded35..f5074478f1ed7 100644
--- a/tests/baselines/reference/tscWatch/programUpdates/rename-a-module-file-and-rename-back-should-restore-the-states-for-inferred-projects.js
+++ b/tests/baselines/reference/tscWatch/programUpdates/rename-a-module-file-and-rename-back-should-restore-the-states-for-inferred-projects.js
@@ -84,7 +84,7 @@ Output::
 [12:00:25 AM] File change detected. Starting incremental compilation...
 
 
-a/b/file1.ts:1:20 - error TS2307: Cannot find module './moduleFile'.
+a/b/file1.ts:1:20 - error TS2307: Cannot find module './moduleFile' or its corresponding type declarations.
 
 1 import * as T from "./moduleFile"; T.bar();
                      ~~~~~~~~~~~~~~
diff --git a/tests/baselines/reference/tscWatch/resolutionCache/works-when-included-file-with-ambient-module-changes.js b/tests/baselines/reference/tscWatch/resolutionCache/works-when-included-file-with-ambient-module-changes.js
index 44d877463a41a..e1ee3c43a7981 100644
--- a/tests/baselines/reference/tscWatch/resolutionCache/works-when-included-file-with-ambient-module-changes.js
+++ b/tests/baselines/reference/tscWatch/resolutionCache/works-when-included-file-with-ambient-module-changes.js
@@ -38,7 +38,7 @@ Output::
 [12:00:15 AM] Starting compilation in watch mode...
 
 
-foo.ts:2:21 - error TS2307: Cannot find module 'fs'.
+foo.ts:2:21 - error TS2307: Cannot find module 'fs' or its corresponding type declarations.
 
 2 import * as fs from "fs";
                       ~~~~
diff --git a/tests/baselines/reference/tscWatch/resolutionCache/works-when-module-resolution-changes-to-ambient-module.js b/tests/baselines/reference/tscWatch/resolutionCache/works-when-module-resolution-changes-to-ambient-module.js
index bb10ad2c313ec..63a69f1c92124 100644
--- a/tests/baselines/reference/tscWatch/resolutionCache/works-when-module-resolution-changes-to-ambient-module.js
+++ b/tests/baselines/reference/tscWatch/resolutionCache/works-when-module-resolution-changes-to-ambient-module.js
@@ -26,7 +26,7 @@ Output::
 [12:00:13 AM] Starting compilation in watch mode...
 
 
-foo.ts:1:21 - error TS2307: Cannot find module 'fs'.
+foo.ts:1:21 - error TS2307: Cannot find module 'fs' or its corresponding type declarations.
 
 1 import * as fs from "fs";
                       ~~~~
diff --git a/tests/baselines/reference/tscWatch/resolutionCache/works-when-renaming-node_modules-folder-that-already-contains-@types-folder.js b/tests/baselines/reference/tscWatch/resolutionCache/works-when-renaming-node_modules-folder-that-already-contains-@types-folder.js
index d9706b77da03c..5292d5cbd3464 100644
--- a/tests/baselines/reference/tscWatch/resolutionCache/works-when-renaming-node_modules-folder-that-already-contains-@types-folder.js
+++ b/tests/baselines/reference/tscWatch/resolutionCache/works-when-renaming-node_modules-folder-that-already-contains-@types-folder.js
@@ -29,7 +29,7 @@ Output::
 [12:00:27 AM] Starting compilation in watch mode...
 
 
-a.ts:1:20 - error TS2307: Cannot find module 'qqq'.
+a.ts:1:20 - error TS2307: Cannot find module 'qqq' or its corresponding type declarations.
 
 1 import * as q from "qqq";
                      ~~~~~
diff --git a/tests/baselines/reference/tscWatch/watchEnvironment/watchDirectories/with-non-synchronous-watch-directory.js b/tests/baselines/reference/tscWatch/watchEnvironment/watchDirectories/with-non-synchronous-watch-directory.js
index 7da9878799745..a69d068cc9db5 100644
--- a/tests/baselines/reference/tscWatch/watchEnvironment/watchDirectories/with-non-synchronous-watch-directory.js
+++ b/tests/baselines/reference/tscWatch/watchEnvironment/watchDirectories/with-non-synchronous-watch-directory.js
@@ -131,7 +131,7 @@ Output::
 [12:00:38 AM] File change detected. Starting incremental compilation...
 
 
-user/username/projects/myproject/src/file1.ts:1:19 - error TS2307: Cannot find module 'file2'.
+user/username/projects/myproject/src/file1.ts:1:19 - error TS2307: Cannot find module 'file2' or its corresponding type declarations.
 
 1 import { x } from "file2";
                     ~~~~~~~
@@ -180,7 +180,7 @@ Output::
 [12:00:43 AM] File change detected. Starting incremental compilation...
 
 
-user/username/projects/myproject/src/file1.ts:1:19 - error TS2307: Cannot find module 'file2'.
+user/username/projects/myproject/src/file1.ts:1:19 - error TS2307: Cannot find module 'file2' or its corresponding type declarations.
 
 1 import { x } from "file2";
                     ~~~~~~~
diff --git a/tests/baselines/reference/tsxNoTypeAnnotatedSFC.errors.txt b/tests/baselines/reference/tsxNoTypeAnnotatedSFC.errors.txt
index 6415843f8a06a..f4f7757af843f 100644
--- a/tests/baselines/reference/tsxNoTypeAnnotatedSFC.errors.txt
+++ b/tests/baselines/reference/tsxNoTypeAnnotatedSFC.errors.txt
@@ -1,11 +1,11 @@
-tests/cases/compiler/tsxNoTypeAnnotatedSFC.tsx(2,24): error TS2307: Cannot find module 'react'.
+tests/cases/compiler/tsxNoTypeAnnotatedSFC.tsx(2,24): error TS2307: Cannot find module 'react' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/tsxNoTypeAnnotatedSFC.tsx (1 errors) ====
     // not _actually_ making react available in this test to regression test #22948
     import * as React from 'react';
                            ~~~~~~~
-!!! error TS2307: Cannot find module 'react'.
+!!! error TS2307: Cannot find module 'react' or its corresponding type declarations.
     
     const Test123 = () => <div/>;
     
diff --git a/tests/baselines/reference/umdDependencyComment2.errors.txt b/tests/baselines/reference/umdDependencyComment2.errors.txt
index 316bac0576ce8..417454b1323af 100644
--- a/tests/baselines/reference/umdDependencyComment2.errors.txt
+++ b/tests/baselines/reference/umdDependencyComment2.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/umdDependencyComment2.ts(3,21): error TS2307: Cannot find module 'm2'.
+tests/cases/compiler/umdDependencyComment2.ts(3,21): error TS2307: Cannot find module 'm2' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/umdDependencyComment2.ts (1 errors) ====
@@ -6,6 +6,6 @@ tests/cases/compiler/umdDependencyComment2.ts(3,21): error TS2307: Cannot find m
     
     import m1 = require("m2")
                         ~~~~
-!!! error TS2307: Cannot find module 'm2'.
+!!! error TS2307: Cannot find module 'm2' or its corresponding type declarations.
     m1.f();
     
\ No newline at end of file
diff --git a/tests/baselines/reference/umdDependencyCommentName1.errors.txt b/tests/baselines/reference/umdDependencyCommentName1.errors.txt
index 197753127d1bd..c6e9c622a58b8 100644
--- a/tests/baselines/reference/umdDependencyCommentName1.errors.txt
+++ b/tests/baselines/reference/umdDependencyCommentName1.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/umdDependencyCommentName1.ts(3,21): error TS2307: Cannot find module 'm2'.
+tests/cases/compiler/umdDependencyCommentName1.ts(3,21): error TS2307: Cannot find module 'm2' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/umdDependencyCommentName1.ts (1 errors) ====
@@ -6,6 +6,6 @@ tests/cases/compiler/umdDependencyCommentName1.ts(3,21): error TS2307: Cannot fi
     
     import m1 = require("m2")
                         ~~~~
-!!! error TS2307: Cannot find module 'm2'.
+!!! error TS2307: Cannot find module 'm2' or its corresponding type declarations.
     m1.f();
     
\ No newline at end of file
diff --git a/tests/baselines/reference/umdDependencyCommentName2.errors.txt b/tests/baselines/reference/umdDependencyCommentName2.errors.txt
index d8920aed91b8b..1777dee81a502 100644
--- a/tests/baselines/reference/umdDependencyCommentName2.errors.txt
+++ b/tests/baselines/reference/umdDependencyCommentName2.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/umdDependencyCommentName2.ts(5,21): error TS2307: Cannot find module 'm2'.
+tests/cases/compiler/umdDependencyCommentName2.ts(5,21): error TS2307: Cannot find module 'm2' or its corresponding type declarations.
 
 
 ==== tests/cases/compiler/umdDependencyCommentName2.ts (1 errors) ====
@@ -8,6 +8,6 @@ tests/cases/compiler/umdDependencyCommentName2.ts(5,21): error TS2307: Cannot fi
     
     import m1 = require("m2")
                         ~~~~
-!!! error TS2307: Cannot find module 'm2'.
+!!! error TS2307: Cannot find module 'm2' or its corresponding type declarations.
     m1.f();
     
\ No newline at end of file
diff --git a/tests/baselines/reference/undeclaredModuleError.errors.txt b/tests/baselines/reference/undeclaredModuleError.errors.txt
index 4a8248bfd6c96..5da647575fcce 100644
--- a/tests/baselines/reference/undeclaredModuleError.errors.txt
+++ b/tests/baselines/reference/undeclaredModuleError.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/undeclaredModuleError.ts(1,21): error TS2307: Cannot find module 'fs'.
+tests/cases/compiler/undeclaredModuleError.ts(1,21): error TS2307: Cannot find module 'fs' or its corresponding type declarations.
 tests/cases/compiler/undeclaredModuleError.ts(8,29): error TS2345: Argument of type '() => void' is not assignable to parameter of type '(stat: any, name: string) => boolean'.
   Type 'void' is not assignable to type 'boolean'.
 tests/cases/compiler/undeclaredModuleError.ts(11,41): error TS2304: Cannot find name 'IDoNotExist'.
@@ -7,7 +7,7 @@ tests/cases/compiler/undeclaredModuleError.ts(11,41): error TS2304: Cannot find
 ==== tests/cases/compiler/undeclaredModuleError.ts (3 errors) ====
     import fs = require('fs');
                         ~~~~
-!!! error TS2307: Cannot find module 'fs'.
+!!! error TS2307: Cannot find module 'fs' or its corresponding type declarations.
     function readdir(path: string, accept: (stat: fs.Stats, name: string) => boolean, callback: (error: Error, results: { name: string; stat: fs.Stats; }[]) => void ) {}
     
     function join(...paths: string[]) {}
diff --git a/tests/baselines/reference/unusedInvalidTypeArguments.errors.txt b/tests/baselines/reference/unusedInvalidTypeArguments.errors.txt
index d524c717980a2..7a600c1bc0b61 100644
--- a/tests/baselines/reference/unusedInvalidTypeArguments.errors.txt
+++ b/tests/baselines/reference/unusedInvalidTypeArguments.errors.txt
@@ -1,11 +1,11 @@
-/call.ts(1,21): error TS2307: Cannot find module 'unknown'.
+/call.ts(1,21): error TS2307: Cannot find module 'unknown' or its corresponding type declarations.
 /callAny.ts(3,1): error TS2347: Untyped function calls may not accept type arguments.
 /callAny.ts(4,1): error TS2347: Untyped function calls may not accept type arguments.
 /callAny.ts(4,3): error TS2304: Cannot find name 'InvalidReference'.
 /classReference.ts(4,24): error TS2315: Type 'C' is not generic.
-/interface.ts(1,21): error TS2307: Cannot find module 'unknown'.
-/new.ts(1,21): error TS2307: Cannot find module 'unkown'.
-/super.ts(1,22): error TS2307: Cannot find module 'unknown'.
+/interface.ts(1,21): error TS2307: Cannot find module 'unknown' or its corresponding type declarations.
+/new.ts(1,21): error TS2307: Cannot find module 'unkown' or its corresponding type declarations.
+/super.ts(1,22): error TS2307: Cannot find module 'unknown' or its corresponding type declarations.
 /super.ts(8,17): error TS2304: Cannot find name 'InvalidReference'.
 /typeReference.ts(6,17): error TS2315: Type 'U' is not generic.
 
@@ -31,20 +31,20 @@
 ==== /interface.ts (1 errors) ====
     import { Foo } from "unknown";
                         ~~~~~~~~~
-!!! error TS2307: Cannot find module 'unknown'.
+!!! error TS2307: Cannot find module 'unknown' or its corresponding type declarations.
     export interface I<T> { x: Foo<T>; }
     
 ==== /call.ts (1 errors) ====
     import { foo } from "unknown";
                         ~~~~~~~~~
-!!! error TS2307: Cannot find module 'unknown'.
+!!! error TS2307: Cannot find module 'unknown' or its corresponding type declarations.
     type T = number;
     foo<T>();
     
 ==== /new.ts (1 errors) ====
     import { Foo } from "unkown";
                         ~~~~~~~~
-!!! error TS2307: Cannot find module 'unkown'.
+!!! error TS2307: Cannot find module 'unkown' or its corresponding type declarations.
     type T = number;
     new Foo<T>();
     
@@ -63,7 +63,7 @@
 ==== /super.ts (2 errors) ====
     import { A, B } from "unknown";
                          ~~~~~~~~~
-!!! error TS2307: Cannot find module 'unknown'.
+!!! error TS2307: Cannot find module 'unknown' or its corresponding type declarations.
     
     type T = number;
     
diff --git a/tests/baselines/reference/user/bcryptjs.log b/tests/baselines/reference/user/bcryptjs.log
index 8de313b8b3fdf..ce69f762b8c82 100644
--- a/tests/baselines/reference/user/bcryptjs.log
+++ b/tests/baselines/reference/user/bcryptjs.log
@@ -1,6 +1,6 @@
 Exit Code: 1
 Standard output:
-node_modules/bcryptjs/scripts/build.js(1,26): error TS2307: Cannot find module 'metascript'.
+node_modules/bcryptjs/scripts/build.js(1,26): error TS2307: Cannot find module 'metascript' or its corresponding type declarations.
 node_modules/bcryptjs/scripts/build.js(32,1): error TS2741: Property 'ISAAC' is missing in type '{ VERSION: any; }' but required in type '{ VERSION: any; ISAAC: boolean; }'.
 node_modules/bcryptjs/src/bcrypt.js(25,13): error TS2740: Type 'Buffer' is missing the following properties from type 'number[]': pop, push, concat, shift, and 5 more.
 node_modules/bcryptjs/src/bcrypt.js(94,14): error TS2366: Function lacks ending return statement and return type does not include 'undefined'.
@@ -29,7 +29,7 @@ node_modules/bcryptjs/src/wrap.js(37,26): error TS2304: Cannot find name 'define
 node_modules/bcryptjs/src/wrap.js(37,51): error TS2304: Cannot find name 'define'.
 node_modules/bcryptjs/src/wrap.js(38,9): error TS2304: Cannot find name 'define'.
 node_modules/bcryptjs/src/wrap.js(49,12): error TS2552: Cannot find name 'bcrypt'. Did you mean 'Crypto'?
-node_modules/bcryptjs/tests/suite.js(3,23): error TS2307: Cannot find module 'bcrypt'.
+node_modules/bcryptjs/tests/suite.js(3,23): error TS2307: Cannot find module 'bcrypt' or its corresponding type declarations.