Index: lib/Sema/SemaLambda.cpp =================================================================== --- lib/Sema/SemaLambda.cpp +++ lib/Sema/SemaLambda.cpp @@ -1492,6 +1492,7 @@ bool ExplicitResultType; CleanupInfo LambdaCleanup; bool ContainsUnexpandedParameterPack; + bool IsGenericLambda; { CallOperator = LSI->CallOperator; Class = LSI->Lambda; @@ -1500,7 +1501,8 @@ ExplicitResultType = !LSI->HasImplicitReturnType; LambdaCleanup = LSI->Cleanup; ContainsUnexpandedParameterPack = LSI->ContainsUnexpandedParameterPack; - + IsGenericLambda = Class->isGenericLambda(); + CallOperator->setLexicalDeclContext(Class); Decl *TemplateOrNonTemplateCallOperatorDecl = CallOperator->getDescribedFunctionTemplate() @@ -1520,8 +1522,13 @@ bool IsImplicit = I >= LSI->NumExplicitCaptures; // Warn about unused explicit captures. - if (!CurContext->isDependentContext() && !IsImplicit && !From.isODRUsed()) - DiagnoseUnusedLambdaCapture(From); + if (!CurContext->isDependentContext() && !IsImplicit && !From.isODRUsed()) { + // Initialized captures that are non-ODR used may not be eliminated. + bool NonODRUsedInitCapture = + IsGenericLambda && From.isNonODRUsed() && From.getInitExpr(); + if (!NonODRUsedInitCapture) + DiagnoseUnusedLambdaCapture(From); + } // Handle 'this' capture. if (From.isThisCapture()) { @@ -1568,8 +1575,7 @@ // same parameter and return types as the closure type's function call // operator. // FIXME: Fix generic lambda to block conversions. - if (getLangOpts().Blocks && getLangOpts().ObjC1 && - !Class->isGenericLambda()) + if (getLangOpts().Blocks && getLangOpts().ObjC1 && !IsGenericLambda) addBlockPointerConversion(*this, IntroducerRange, Class, CallOperator); // Finalize the lambda class. Index: test/SemaCXX/warn-unused-lambda-capture.cpp =================================================================== --- test/SemaCXX/warn-unused-lambda-capture.cpp +++ test/SemaCXX/warn-unused-lambda-capture.cpp @@ -142,11 +142,14 @@ auto implicit_by_reference = [&] { i++; }; auto explicit_by_value_used = [i] { return i + 1; }; + auto explicit_by_value_used_generic = [i](auto c) { return i + 1; }; auto explicit_by_value_used_void = [i] { (void)i; }; + auto explicit_by_value_unused = [i] {}; // expected-warning{{lambda capture 'i' is not used}} auto explicit_by_value_unused_sizeof = [i] { return sizeof(i); }; // expected-warning{{lambda capture 'i' is not required to be captured for this use}} auto explicit_by_value_unused_decltype = [i] { decltype(i) j = 0; }; // expected-warning{{lambda capture 'i' is not used}} auto explicit_by_value_unused_const = [k] { return k + 1; }; // expected-warning{{lambda capture 'k' is not required to be captured for this use}} + auto explicit_by_value_unused_const_generic = [k](auto c) { return k + 1; }; // expected-warning{{lambda capture 'k' is not required to be captured for this use}} auto explicit_by_reference_used = [&i] { i++; }; auto explicit_by_reference_unused = [&i] {}; // expected-warning{{lambda capture 'i' is not used}} @@ -161,6 +164,8 @@ auto explicit_initialized_value_trivial_init = [j = Trivial()]{}; // expected-warning{{lambda capture 'j' is not used}} auto explicit_initialized_value_non_trivial_init = [j = Trivial(42)]{}; auto explicit_initialized_value_with_side_effect = [j = side_effect()]{}; + auto explicit_initialized_value_generic_used = [i = 1](auto c) mutable { i++; }; + auto explicit_initialized_value_generic_unused = [i = 1](auto c) mutable {}; // expected-warning{{lambda capture 'i' is not used}} auto nested = [&i] { auto explicit_by_value_used = [i] { return i + 1; };