Author: Corentin Jabot Date: 2025-07-08T17:41:11+02:00 New Revision: e29ac9bc2e0ae8871dccea939554b39589cc07bd
URL: https://github.com/llvm/llvm-project/commit/e29ac9bc2e0ae8871dccea939554b39589cc07bd DIFF: https://github.com/llvm/llvm-project/commit/e29ac9bc2e0ae8871dccea939554b39589cc07bd.diff LOG: [Clang] Do not mark ambiguous specialization invalid. (#147275) When a specialization was ambiguous, we would mark it as invalid, even if the specialization occured in an immediate context. This would subsequently lead to scenarios where invalid specialization produced no diagnostics, causing crashes during codegen. Fixes #51866 Added: Modified: clang/docs/ReleaseNotes.rst clang/lib/Sema/SemaTemplateInstantiate.cpp clang/test/SemaTemplate/partial-order.cpp Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 805095e4c77ef..712229cd11565 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -913,6 +913,7 @@ Bug Fixes to C++ Support - Fix a bug where private access specifier of overloaded function not respected. (#GH107629) - Correctly handle allocations in the condition of a ``if constexpr``.(#GH120197) (#GH134820) - Fixed a crash when handling invalid member using-declaration in C++20+ mode. (#GH63254) +- Fix a crash when trying to instantiate an ambiguous specialization. (#GH51866) Bug Fixes to AST Handling ^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp b/clang/lib/Sema/SemaTemplateInstantiate.cpp index a1c7143e3b874..9140f00fcd740 100644 --- a/clang/lib/Sema/SemaTemplateInstantiate.cpp +++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp @@ -4111,7 +4111,6 @@ static ActionResult<CXXRecordDecl *> getPatternForClassTemplateSpecialization( if (Ambiguous) { // Partial ordering did not produce a clear winner. Complain. Inst.Clear(); - ClassTemplateSpec->setInvalidDecl(); S.Diag(PointOfInstantiation, diag::err_partial_spec_ordering_ambiguous) << ClassTemplateSpec; diff --git a/clang/test/SemaTemplate/partial-order.cpp b/clang/test/SemaTemplate/partial-order.cpp index db2624d1766bc..2619524b147ae 100644 --- a/clang/test/SemaTemplate/partial-order.cpp +++ b/clang/test/SemaTemplate/partial-order.cpp @@ -47,3 +47,29 @@ namespace GH132562 { // expected-note@-2 {{value of type 'const J' is not implicitly convertible to 'int'}} } // namespace t3 } // namespace GH132562 + +namespace GH51866 { + +template <class> struct Trait; +template <class T> + requires T::one +struct Trait<T> {}; // #gh51866-one +template <class T> + requires T::two +struct Trait<T> {}; // #gh51866-two + +struct Y { + static constexpr bool one = true; + static constexpr bool two = true; +}; + +template <class T> +concept C = sizeof(Trait<T>) != 0; + +static_assert(!C<Y>); + +Trait<Y> t; +// expected-error@-1{{ambiguous partial specializations of 'Trait<GH51866::Y>'}} +// expected-note@#gh51866-one{{partial specialization matches}} +// expected-note@#gh51866-two{{partial specialization matches}} +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
