diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td --- a/clang/include/clang/Basic/Attr.td +++ b/clang/include/clang/Basic/Attr.td @@ -2939,10 +2939,16 @@ let SimpleHandler = 1; } +def WarnUnusedResultClang : InheritableAttr { + let Spellings = [CXX11<"clang", "warn_unused_result">]; + let Subjects = SubjectList<[ObjCMethod, Enum, Record, FunctionLike, TypedefName]>; + let Args = [StringArgument<"Message", 1>]; + let Documentation = [WarnUnusedResultsDocs]; +} + def WarnUnusedResult : InheritableAttr { let Spellings = [CXX11<"", "nodiscard", 201907>, C2x<"", "nodiscard", 201904>, - CXX11<"clang", "warn_unused_result">, GCC<"warn_unused_result">]; let Subjects = SubjectList<[ObjCMethod, Enum, Record, FunctionLike]>; let Args = [StringArgument<"Message", 1>]; diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp --- a/clang/lib/AST/Expr.cpp +++ b/clang/lib/AST/Expr.cpp @@ -1522,6 +1522,10 @@ if (const auto *A = TD->getAttr()) return A; + if (const auto *TD = getCallReturnType(Ctx)->getAs()) + if (const auto *A = TD->getDecl()->getAttr()) + return A; + // Otherwise, see if the callee is marked nodiscard and return that attribute // instead. const Decl *D = getCalleeDecl(); diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp --- a/clang/lib/Sema/SemaDeclAttr.cpp +++ b/clang/lib/Sema/SemaDeclAttr.cpp @@ -8740,6 +8740,9 @@ case ParsedAttr::AT_WarnUnusedResult: handleWarnUnusedResult(S, D, AL); break; + case ParsedAttr::AT_WarnUnusedResultClang: + handleWarnUnusedResult(S, D, AL); + break; case ParsedAttr::AT_WeakRef: handleWeakRefAttr(S, D, AL); break; diff --git a/clang/test/Misc/pragma-attribute-supported-attributes-list.test b/clang/test/Misc/pragma-attribute-supported-attributes-list.test --- a/clang/test/Misc/pragma-attribute-supported-attributes-list.test +++ b/clang/test/Misc/pragma-attribute-supported-attributes-list.test @@ -186,6 +186,7 @@ // CHECK-NEXT: VecTypeHint (SubjectMatchRule_function) // CHECK-NEXT: WarnUnused (SubjectMatchRule_record) // CHECK-NEXT: WarnUnusedResult (SubjectMatchRule_objc_method, SubjectMatchRule_enum, SubjectMatchRule_record, SubjectMatchRule_hasType_functionType) +// CHECK-NEXT: WarnUnusedResultClang (SubjectMatchRule_objc_method, SubjectMatchRule_enum, SubjectMatchRule_record, SubjectMatchRule_hasType_functionType, SubjectMatchRule_type_alias) // CHECK-NEXT: Weak (SubjectMatchRule_variable, SubjectMatchRule_function, SubjectMatchRule_record) // CHECK-NEXT: WeakRef (SubjectMatchRule_variable, SubjectMatchRule_function) // CHECK-NEXT: WebAssemblyExportName (SubjectMatchRule_function) diff --git a/clang/test/SemaCXX/warn-unused-result.cpp b/clang/test/SemaCXX/warn-unused-result.cpp --- a/clang/test/SemaCXX/warn-unused-result.cpp +++ b/clang/test/SemaCXX/warn-unused-result.cpp @@ -254,3 +254,15 @@ void i([[nodiscard]] bool (*fp)()); // expected-warning {{'nodiscard' attribute only applies to functions, classes, or enumerations}} } + +namespace unused_typedef_result { +[[clang::warn_unused_result]] typedef void *p; +p f1(); +void f2() { + f1(); // expected-warning {{ignoring return value}} + void *(*p1)(); + p1(); // no warning + p (*p2)(); + p2(); // expected-warning {{ignoring return value}} +} +}