Author: erichkeane Date: Tue Jun 20 12:38:07 2017 New Revision: 305812 URL: http://llvm.org/viewvc/llvm-project?rev=305812&view=rev Log: Fix for Bug 33471: Preventing operator auto from resolving to a template operator.
As the bug report says, struct A { template<typename T> operator T(); }; void foo() { A().operator auto(); } causes: "undeduced type in IR-generation UNREACHABLE executed at llvm/tools/clang/lib/CodeGen/CodeGenFunction.cpp:208!" The problem is that in this case, "T" is being deduced as "auto", which I believe is incorrect. The 'operator auto' implementation in Clang is standards compliant, however there is a defect report against core (1670). Differential Revision: https://reviews.llvm.org/D34370 Modified: cfe/trunk/lib/Sema/SemaLookup.cpp cfe/trunk/test/SemaCXX/cxx1y-deduced-return-type.cpp Modified: cfe/trunk/lib/Sema/SemaLookup.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaLookup.cpp?rev=305812&r1=305811&r2=305812&view=diff ============================================================================== --- cfe/trunk/lib/Sema/SemaLookup.cpp (original) +++ cfe/trunk/lib/Sema/SemaLookup.cpp Tue Jun 20 12:38:07 2017 @@ -862,6 +862,16 @@ static bool LookupDirect(Sema &S, Lookup if (!Record->isCompleteDefinition()) return Found; + // For conversion operators, 'operator auto' should only match + // 'operator auto'. Since 'auto' is not a type, it shouldn't be considered + // as a candidate for template substitution. + auto *ContainedDeducedType = + R.getLookupName().getCXXNameType()->getContainedDeducedType(); + if (R.getLookupName().getNameKind() == + DeclarationName::CXXConversionFunctionName && + ContainedDeducedType && ContainedDeducedType->isUndeducedType()) + return Found; + for (CXXRecordDecl::conversion_iterator U = Record->conversion_begin(), UEnd = Record->conversion_end(); U != UEnd; ++U) { FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(*U); Modified: cfe/trunk/test/SemaCXX/cxx1y-deduced-return-type.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/cxx1y-deduced-return-type.cpp?rev=305812&r1=305811&r2=305812&view=diff ============================================================================== --- cfe/trunk/test/SemaCXX/cxx1y-deduced-return-type.cpp (original) +++ cfe/trunk/test/SemaCXX/cxx1y-deduced-return-type.cpp Tue Jun 20 12:38:07 2017 @@ -55,6 +55,25 @@ auto b(bool k) { return "goodbye"; } +// Allow 'operator auto' to call only the explicit operator auto. +struct BothOps { + template <typename T> operator T(); + template <typename T> operator T *(); + operator auto() { return 0; } + operator auto *() { return this; } +}; +struct JustTemplateOp { + template <typename T> operator T(); + template <typename T> operator T *(); +}; + +auto c() { + BothOps().operator auto(); // ok + BothOps().operator auto *(); // ok + JustTemplateOp().operator auto(); // expected-error {{no member named 'operator auto' in 'JustTemplateOp'}} + JustTemplateOp().operator auto *(); // expected-error {{no member named 'operator auto *' in 'JustTemplateOp'}} +} + auto *ptr_1() { return 100; // expected-error {{cannot deduce return type 'auto *' from returned value of type 'int'}} } _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits