Re-use unsupported def error message for must_bind.

cc_bindings_from_rs/generate_bindings/generate_bindings_test.rs

@@ -1328,7 +1328,8 @@ fn test_format_item_static_method_with_generic_type_parameters() {
     test_format_item(test_src, "SomeStruct", |result| {
         let result = result.unwrap().unwrap();
         let main_api = &result.main_api;
-        let unsupported_msg = "Error generating bindings for `SomeStruct::generic_method` \
+        let unsupported_msg =
+            "Error generating bindings for associated function `SomeStruct::generic_method` \
                                defined at <crubit_unittests.rs>;l=12: \
                                No valid non-generic replacement for generic type param `T`";
         assert_cc_matches!(
@@ -1670,7 +1671,8 @@ fn test_format_item_method_taking_self_by_arc() {
     test_format_item(test_src, "SomeStruct", |result| {
         let result = result.unwrap().unwrap();
         let main_api = &result.main_api;
-        let unsupported_msg = "Error generating bindings for `SomeStruct::get_f32` \
+        let unsupported_msg =
+            "Error generating bindings for associated function `SomeStruct::get_f32` \
                                defined at <crubit_unittests.rs>;l=7: \
                                Unsupported `self` type `std::sync::Arc<SomeStruct>`";
         assert_cc_matches!(
@@ -1706,7 +1708,8 @@ fn test_format_item_method_taking_self_by_pinned_mut_ref() {
     test_format_item(test_src, "SomeStruct", |result| {
         let result = result.unwrap().unwrap();
         let main_api = &result.main_api;
-        let unsupported_msg = "Error generating bindings for `SomeStruct::set_f32` \
+        let unsupported_msg =
+            "Error generating bindings for associated function `SomeStruct::set_f32` \
                                defined at <crubit_unittests.rs>;l=7: \
                                Unsupported `self` type `std::pin::Pin<&'__anon1 mut SomeStruct>`";
         assert_cc_matches!(

cc_bindings_from_rs/generate_bindings/lib.rs

@@ -1587,28 +1587,14 @@ pub(crate) fn report_must_bind_error<'tcx>(
 ) {
     let tcx = db.tcx();
     let item_path = tcx.def_path_str(def_id);
-    let def_kind = tcx.def_kind(def_id);
-    let kind_str = match def_kind {
-        rustc_hir::def::DefKind::Struct => "struct",
-        rustc_hir::def::DefKind::Enum => "enum",
-        rustc_hir::def::DefKind::Union => "union",
-        rustc_hir::def::DefKind::Fn => "function",
-        rustc_hir::def::DefKind::TyAlias => "type alias",
-        rustc_hir::def::DefKind::Const { .. } => "constant",
-        rustc_hir::def::DefKind::Trait => "trait",
-        rustc_hir::def::DefKind::AssocFn => "function",
-        rustc_hir::def::DefKind::AssocConst { .. } => "constant",
-        rustc_hir::def::DefKind::AssocTy => "associated type",
-        _ => "item",
-    };
     let error_details = format!("  {err:#}").replace('\n', "\n  ");
     let bold = "\x1B[1m";
     let reset = "\x1B[0m";
     let red = "\x1B[31m";
     let must_bind_message = format!(
-        "{bold}{red}error:{reset}{bold} {kind_str} `{item_path}` could not be bound{reset}\n\
-        {error_details}\n\
-        {bold}note:{reset} hard error because `#[crubit_annotate::must_bind]` was applied to `{item_path}`"
+        "{bold}{red}error:{reset}{bold}{}\n\
+        {bold}note:{reset} hard error because `#[crubit_annotate::must_bind]` was applied to `{item_path}`",
+        unsupported_def_error_message(db, def_id, err, ErrorStyle::Terminal),
     );
     db.fatal_errors().report(&must_bind_message);
 }
@@ -1670,6 +1656,37 @@ fn generate_item_impl<'tcx>(
     }
 }
 
+enum ErrorStyle {
+    // This message will be formatted as a comment.
+    Comment,
+    // This message will be printed to a terminal.
+    Terminal,
+}
+
+pub(crate) fn unsupported_def_error_message(
+    db: &BindingsGenerator,
+    def_id: DefId,
+    err: &Error,
+    style: ErrorStyle,
+) -> String {
+    let tcx = db.tcx();
+    let source_loc = generate_source_location(db, def_id);
+    let name = tcx.def_path_str(def_id);
+    let def_kind = tcx.def_kind(def_id);
+    let kind_str = def_kind.descr(def_id);
+    let err_msg = if let ErrorStyle::Terminal = style {
+        format!("\n  {err:#}").replace('\n', "\n  ")
+    } else {
+        format!(" {err:#}")
+    };
+    let bold = if let ErrorStyle::Terminal = style { "\x1B[1m" } else { "" };
+    let reset = if let ErrorStyle::Terminal = style { "\x1B[0m" } else { "" };
+
+    // https://docs.rs/anyhow/latest/anyhow/struct.Error.html#display-representations
+    // says: To print causes as well [...], use the alternate selector “{:#}”.
+    format!("{bold}{kind_str} `{name}` defined at {source_loc}:{reset}{err_msg}")
+}
+
 /// Formats a C++ comment explaining why no bindings have been generated for
 /// `local_def_id`.
 pub(crate) fn generate_unsupported_def<'tcx>(
@@ -1680,12 +1697,10 @@ pub(crate) fn generate_unsupported_def<'tcx>(
     let tcx = db.tcx();
     db.errors().assert_in_item(item_name_for_error_report(db, def_id));
     db.errors().report(&err);
-    let source_loc = generate_source_location(db, def_id);
-    let name = tcx.def_path_str(def_id);
-
-    // https://docs.rs/anyhow/latest/anyhow/struct.Error.html#display-representations
-    // says: To print causes as well [...], use the alternate selector “{:#}”.
-    let msg = format!("Error generating bindings for `{name}` defined at {source_loc}: {err:#}");
+    let msg = format!(
+        "Error generating bindings for {}",
+        unsupported_def_error_message(db, def_id, &err, ErrorStyle::Comment)
+    );
     CcSnippet::new(quote! { __NEWLINE__ __NEWLINE__ __COMMENT__ #msg __NEWLINE__ })
 }
 

cc_bindings_from_rs/test/arrays/arrays_cc_api.h

@@ -208,20 +208,20 @@ ::std::array<::std::array<::arrays::HasDropAndDefault, 2>, 2>
 function_with_nested_drop_default_arrays(
     ::std::array<::std::array<::arrays::HasDropAndDefault, 2>, 2> array);
 
-// Error generating bindings for
+// Error generating bindings for function
 // `arrays_golden::function_with_nested_droponly_arrays` defined at
 // cc_bindings_from_rs/test/arrays/arrays.rs;l=98:
 // b/260128806 - nested array [arrays_golden::HasDrop; 2] is not supported
 // because it contains a type that implements Drop but not Default
 
-// Error generating bindings for
+// Error generating bindings for function
 // `arrays_golden::function_with_nested_nested_droponly_arrays` defined at
 // cc_bindings_from_rs/test/arrays/arrays.rs;l=104:
 // b/260128806 - nested array [[arrays_golden::HasDrop; 2]; 2] is not supported
 // because it contains a type that implements Drop but not Default
 
-// Error generating bindings for `arrays_golden::function_with_tuple_array_id`
-// defined at
+// Error generating bindings for function
+// `arrays_golden::function_with_tuple_array_id` defined at
 // cc_bindings_from_rs/test/arrays/arrays.rs;l=27:
 // Tuple types cannot be used inside of compound data types, because std::tuple
 // is not layout-compatible with a Rust tuple.

cc_bindings_from_rs/test/enums/enums_cc_api.h

@@ -54,7 +54,8 @@ struct CRUBIT_INTERNAL_RUST_TYPE(":: enums_golden :: repr_c :: MyEnum") alignas(
   // cc_bindings_from_rs/test/enums/enums.rs;l=14
   static MyEnum MakeF();
 
-  // Error generating bindings for `enums_golden::repr_c::MyEnum::Z` defined at
+  // Error generating bindings for variant `enums_golden::repr_c::MyEnum::Z`
+  // defined at
   // cc_bindings_from_rs/test/enums/enums.rs;l=15:
   // Tuple types cannot be used inside of compound data types, because
   // std::tuple is not layout-compatible with a Rust tuple.
@@ -63,12 +64,14 @@ struct CRUBIT_INTERNAL_RUST_TYPE(":: enums_golden :: repr_c :: MyEnum") alignas(
   // cc_bindings_from_rs/test/enums/enums.rs;l=16
   static MyEnum MakeG();
 
-  // Error generating bindings for `enums_golden::repr_c::MyEnum::B` defined at
+  // Error generating bindings for variant `enums_golden::repr_c::MyEnum::B`
+  // defined at
   // cc_bindings_from_rs/test/enums/enums.rs;l=17:
   // Constructing non-tuple, struct-like enum variants is not supported:
   // b/487357254
 
-  // Error generating bindings for `enums_golden::repr_c::MyEnum::C` defined at
+  // Error generating bindings for variant `enums_golden::repr_c::MyEnum::C`
+  // defined at
   // cc_bindings_from_rs/test/enums/enums.rs;l=18:
   // Constructing non-tuple, struct-like enum variants is not supported:
   // b/487357254
@@ -254,7 +257,7 @@ struct CRUBIT_INTERNAL_RUST_TYPE(
   // Default::default
   CloneCount();
 
-  // Error generating bindings for
+  // Error generating bindings for variant
   // `enums_golden::repr_c_clone_counter::CloneCount::A` defined at
   // cc_bindings_from_rs/test/enums/enums.rs;l=56:
   // Constructing non-tuple, struct-like enum variants is not supported:
@@ -324,8 +327,8 @@ struct CRUBIT_INTERNAL_RUST_TYPE(
   // cc_bindings_from_rs/test/enums/enums.rs;l=34
   static DropMe MakeQ();
 
-  // Error generating bindings for `enums_golden::repr_c_drop::DropMe::C`
-  // defined at
+  // Error generating bindings for variant
+  // `enums_golden::repr_c_drop::DropMe::C` defined at
   // cc_bindings_from_rs/test/enums/enums.rs;l=35:
   // Constructing non-tuple, struct-like enum variants is not supported:
   // b/487357254
@@ -481,7 +484,7 @@ struct CRUBIT_INTERNAL_RUST_TYPE(
   static ::enums::repr_rust::RustReprEnum MakeTuplePayloadVariant(
       ::std::int32_t __param_0, ::std::int32_t __param_1);
 
-  // Error generating bindings for
+  // Error generating bindings for variant
   // `enums_golden::repr_rust::RustReprEnum::StructPayloadVariant` defined at
   // cc_bindings_from_rs/test/enums/enums.rs;l=122:
   // Constructing non-tuple, struct-like enum variants is not supported:
@@ -537,19 +540,19 @@ struct CRUBIT_INTERNAL_RUST_TYPE(
   // doesn't implement the `Default` trait
   RustReprWithNamingConflictBetweenCtorsAndMethods() = delete;
 
-  // Error generating bindings for
+  // Error generating bindings for variant
   // `enums_golden::repr_rust::RustReprWithNamingConflictBetweenCtorsAndMethods::NoPayloadVariant`
   // defined at
   // cc_bindings_from_rs/test/enums/enums.rs;l=160:
   // Conflicting member function name: MakeNoPayloadVariant
 
-  // Error generating bindings for
+  // Error generating bindings for variant
   // `enums_golden::repr_rust::RustReprWithNamingConflictBetweenCtorsAndMethods::TuplePayloadVariant`
   // defined at
   // cc_bindings_from_rs/test/enums/enums.rs;l=161:
   // Conflicting member function name: MakeTuplePayloadVariant
 
-  // Error generating bindings for
+  // Error generating bindings for variant
   // `enums_golden::repr_rust::RustReprWithNamingConflictBetweenCtorsAndMethods::StructPayloadVariant`
   // defined at
   // cc_bindings_from_rs/test/enums/enums.rs;l=162:
@@ -610,7 +613,7 @@ struct CRUBIT_INTERNAL_RUST_TYPE(
   static void __crubit_field_offset_assertions();
 };
 
-// Error generating bindings for
+// Error generating bindings for enum
 // `enums_golden::repr_rust::RustReprWithSingleNoPayloadVariant` defined at
 // cc_bindings_from_rs/test/enums/enums.rs;l=151:
 // Zero-sized types (ZSTs) are not supported (b/258259459)

cc_bindings_from_rs/test/enums/option_cc_api.h

@@ -38,7 +38,7 @@
 namespace option {
 struct HasOptions;
 
-// Error generating bindings for `option_golden::BridgedType` defined at
+// Error generating bindings for struct `option_golden::BridgedType` defined at
 // cc_bindings_from_rs/test/enums/option.rs;l=178:
 // Type bindings for option_golden::BridgedType suppressed due to being mapped
 // to an existing C++ type (int)
@@ -230,8 +230,8 @@ struct CRUBIT_INTERNAL_RUST_TYPE(":: option_golden :: NonMaxU8") alignas(1)
   static void __crubit_field_offset_assertions();
 };
 
-// Error generating bindings for `option_golden::OptUninhabited` defined at
-// cc_bindings_from_rs/test/enums/option.rs;l=153:
+// Error generating bindings for struct `option_golden::OptUninhabited` defined
+// at cc_bindings_from_rs/test/enums/option.rs;l=153:
 // Zero-sized types (ZSTs) are not supported (b/258259459)
 
 // Generated from:
@@ -298,15 +298,16 @@ OptionWithSizeTypes final {
   static void __crubit_field_offset_assertions();
 };
 
-// Error generating bindings for `option_golden::UninhabitedEnum` defined at
-// cc_bindings_from_rs/test/enums/option.rs;l=151:
+// Error generating bindings for enum `option_golden::UninhabitedEnum` defined
+// at cc_bindings_from_rs/test/enums/option.rs;l=151:
 // Zero-sized types (ZSTs) are not supported (b/258259459)
 
-// Error generating bindings for `option_golden::Unit` defined at
+// Error generating bindings for struct `option_golden::Unit` defined at
 // cc_bindings_from_rs/test/enums/option.rs;l=158:
 // Zero-sized types (ZSTs) are not supported (b/258259459)
 
-// Error generating bindings for `option_golden::take_option_bridged` defined at
+// Error generating bindings for function `option_golden::take_option_bridged`
+// defined at
 // cc_bindings_from_rs/test/enums/option.rs;l=180:
 // Error handling parameter #0 of type
 // `std::option::Option<option_golden::BridgedType>`: Failed to format type for

cc_bindings_from_rs/test/function_pointers/function_pointers_cc_api.h

@@ -29,12 +29,12 @@
 
 namespace function_pointers {
 
-// Error generating bindings for
+// Error generating bindings for constant
 // `function_pointers_golden::CONST_C_FN_PTR_ADD_TEN` defined at
 // cc_bindings_from_rs/test/function_pointers/function_pointers.rs;l=27:
 // Pointer values cannot be used as scalar constants.
 
-// Error generating bindings for
+// Error generating bindings for constant
 // `function_pointers_golden::CONST_RUST_FN_PTR_ADD_TEN` defined at
 // cc_bindings_from_rs/test/function_pointers/function_pointers.rs;l=26:
 // Function pointers can't have a thunk: Any calling convention other than
@@ -125,19 +125,19 @@ void call_fn_ptr_no_args_or_return(crubit::type_identity_t<void()>& fn_ptr);
 ::std::int32_t call_fn_ptr_with_five(
     crubit::type_identity_t<::std::int32_t(::std::int32_t)>& fn_ptr);
 
-// Error generating bindings for
+// Error generating bindings for function
 // `function_pointers_golden::call_fn_ptr_with_five_reference` defined at
 // cc_bindings_from_rs/test/function_pointers/function_pointers.rs;l=45:
 // Error handling parameter #0 of type `for<'a> extern "C" fn(&'a i32) -> i32`:
 // Generic function pointers are not supported yet (b/259749023)
 
-// Error generating bindings for
+// Error generating bindings for function
 // `function_pointers_golden::call_fn_ptr_with_five_reference_hrtb` defined at
 // cc_bindings_from_rs/test/function_pointers/function_pointers.rs;l=50:
 // Error handling parameter #0 of type `for<'a> extern "C" fn(&'a i32) -> i32`:
 // Generic function pointers are not supported yet (b/259749023)
 
-// Error generating bindings for
+// Error generating bindings for function
 // `function_pointers_golden::call_fn_ptr_with_repr_c_struct` defined at
 // cc_bindings_from_rs/test/function_pointers/function_pointers.rs;l=69:
 // Error handling parameter #0 of type `extern "C"
@@ -152,15 +152,15 @@ ::std::int32_t call_fn_ptr_with_repr_c_struct_ptr_containing_seven(
     crubit::type_identity_t<
         ::std::int32_t(::function_pointers::CStruct const*)>& fn_ptr);
 
-// Error generating bindings for
+// Error generating bindings for function
 // `function_pointers_golden::call_fn_ptr_with_repr_c_struct_ref` defined at
 // cc_bindings_from_rs/test/function_pointers/function_pointers.rs;l=74:
 // Error handling parameter #0 of type `for<'a> extern "C" fn(&'a
 // function_pointers_golden::CStruct) -> i32`: Generic function pointers are not
 // supported yet (b/259749023)
 
-// Error generating bindings for `function_pointers_golden::call_rust_fn_ptr`
-// defined at
+// Error generating bindings for function
+// `function_pointers_golden::call_rust_fn_ptr` defined at
 // cc_bindings_from_rs/test/function_pointers/function_pointers.rs;l=35:
 // Error handling parameter #0 of type `fn()`: Function pointers can't have a
 // thunk: Any calling convention other than `extern "C"` requires a thunk

cc_bindings_from_rs/test/functions/functions_cc_api.h

@@ -258,7 +258,7 @@ ::std::int32_t return_type();
 // cc_bindings_from_rs/test/functions/functions.rs;l=169
 ::std::int32_t reused_generic_param(::std::int32_t x, ::std::int32_t y);
 
-// Error generating bindings for
+// Error generating bindings for function
 // `functions_golden::generic_fn_tests::into_trait_tests::unused_generic_param`
 // defined at
 // cc_bindings_from_rs/test/functions/functions.rs;l=204:

cc_bindings_from_rs/test/golden/composable_bridging_cc_api.h

@@ -27,13 +27,13 @@
 
 namespace composable_bridging_rust {
 
-// Error generating bindings for `composable_bridging_rust_golden::MyOptionRust`
-// defined at
+// Error generating bindings for struct
+// `composable_bridging_rust_golden::MyOptionRust` defined at
 // cc_bindings_from_rs/test/golden/composable_bridging.rs;l=39:
 // Type bindings for composable_bridging_rust_golden::MyOptionRust suppressed
 // due to being mapped to an existing C++ type (std::optional)
 
-// Error generating bindings for
+// Error generating bindings for struct
 // `composable_bridging_rust_golden::MyOptionRustAbi` defined at
 // cc_bindings_from_rs/test/golden/composable_bridging.rs;l=50:
 // Generic types are not supported yet (b/259749095)

cc_bindings_from_rs/test/known_traits/index/rs_index_cc_api.h

@@ -134,7 +134,7 @@ struct CRUBIT_INTERNAL_RUST_TYPE(":: rs_index_golden :: IntPair") alignas(4)
   // cc_bindings_from_rs/test/known_traits/index/rs_index.rs;l=22
   ::std::int32_t const& $(__anon1) operator[](::std::uintptr_t index) const&;
 
-  // Error generating bindings for `<rs_index_golden::IntPair as
+  // Error generating bindings for implementation `<rs_index_golden::IntPair as
   // std::ops::Index<u64>>` defined at
   // cc_bindings_from_rs/test/known_traits/index/rs_index.rs;l=44:
   // Index implementation for `u64` is not supported when `Index<usize>` is
@@ -149,7 +149,7 @@ struct CRUBIT_INTERNAL_RUST_TYPE(":: rs_index_golden :: IntPair") alignas(4)
   // cc_bindings_from_rs/test/known_traits/index/rs_index.rs;l=34
   ::std::int32_t& $(__anon1) operator[](::std::uintptr_t index) &;
 
-  // Error generating bindings for `<rs_index_golden::IntPair as
+  // Error generating bindings for implementation `<rs_index_golden::IntPair as
   // std::ops::IndexMut<u64>>` defined at
   // cc_bindings_from_rs/test/known_traits/index/rs_index.rs;l=56:
   // Index implementation for `u64` is not supported when `Index<usize>` is
@@ -211,7 +211,7 @@ struct CRUBIT_INTERNAL_RUST_TYPE(":: rs_index_golden :: Map") alignas(8)
   // cc_bindings_from_rs/test/known_traits/index/rs_index.rs;l=134
   rs_std::StrRef operator[](::rs_index::Id const* crubit_nonnull index) const&;
 
-  // Error generating bindings for `<rs_index_golden::Map as
+  // Error generating bindings for implementation `<rs_index_golden::Map as
   // std::ops::IndexMut<(usize, usize)>>` defined at
   // cc_bindings_from_rs/test/known_traits/index/rs_index.rs;l=121:
   // Mutable references to `str` are not yet supported.

cc_bindings_from_rs/test/modules/modules_cc_api.h

@@ -98,7 +98,7 @@ namespace modules::outer {
 
 namespace [[deprecated]] inner_deprecated {
 
-// Error generating bindings for
+// Error generating bindings for struct
 // `modules_golden::outer::inner_deprecated::SomeType` defined at
 // cc_bindings_from_rs/test/modules/modules.rs;l=26:
 // Zero-sized types (ZSTs) are not supported (b/258259459)
@@ -111,7 +111,7 @@ namespace modules::outer::middle {
 
 namespace [[deprecated]] innermost_deprecated {
 
-// Error generating bindings for
+// Error generating bindings for struct
 // `modules_golden::outer::middle::innermost_deprecated::SomeType` defined at
 // cc_bindings_from_rs/test/modules/modules.rs;l=32:
 // Zero-sized types (ZSTs) are not supported (b/258259459)