llvmorg-github-actions[bot] wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: Qixi (Qixi-1) <details> <summary>Changes</summary> …36813) When generating implicit deduction guides for nested template classes, transformFunctionTypeParam calls SubstType to substitute outer template parameters. However, SubstType fails to substitute through InjectedClassNameType because TreeTransform does not reach TransformTagType for it in this context, leaving outer template parameters unsubstituted in the deduction guide parameter type. Later, MarkUsedTemplateParameters traverses the unsubstituted parameter type and encounters template parameter indices that exceed the SmallBitVector size (allocated for the inner template), causing an out-of-bounds access. Fix by expanding InjectedClassNameType to its canonical TemplateSpecializationType before calling SubstType when transforming outer patterns, so that the outer template parameters can be properly substituted. Fixes #<!-- -->136813. --- Full diff: https://github.com/llvm/llvm-project/pull/207644.diff 2 Files Affected: - (modified) clang/lib/Sema/SemaTemplateDeductionGuide.cpp (+21-1) - (added) clang/test/SemaTemplate/nested-implicit-deduction-guides-crash.cpp (+22) ``````````diff diff --git a/clang/lib/Sema/SemaTemplateDeductionGuide.cpp b/clang/lib/Sema/SemaTemplateDeductionGuide.cpp index 15b6aea749584..36ecf664c71fc 100644 --- a/clang/lib/Sema/SemaTemplateDeductionGuide.cpp +++ b/clang/lib/Sema/SemaTemplateDeductionGuide.cpp @@ -836,9 +836,29 @@ struct ConvertConstructorToDeductionGuideTransform { NewTSI = SemaRef.CheckPackExpansion(NewTSI, PackTL.getEllipsisLoc(), PackTL.getTypePtr()->getNumExpansions()); - } else + } else{ + // When transforming outer patterns, InjectedClassNameType may not be + // substituted by SubstType because TreeTransform does not always + // reach TransformTagType for nested InjectedClassNameType. Expand it + // to TemplateSpecializationType first so substitution can proceed. + if (TransformingOuterPatterns) { + QualType OldType = OldTSI->getType().getNonReferenceType(); + if (const auto *ICNT = dyn_cast<InjectedClassNameType>(OldType)) { + QualType Expanded = + ICNT->getDecl()->getCanonicalTemplateSpecializationType( + SemaRef.Context); + // Rebuild the type with the expanded form + if (OldTSI->getType()->isLValueReferenceType()) + Expanded = SemaRef.Context.getLValueReferenceType(Expanded); + else if (OldTSI->getType()->isRValueReferenceType()) + Expanded = SemaRef.Context.getRValueReferenceType(Expanded); + OldTSI = SemaRef.Context.getTrivialTypeSourceInfo( + Expanded, OldParam->getLocation()); + } + } NewTSI = SemaRef.SubstType(OldTSI, Args, OldParam->getLocation(), OldParam->getDeclName()); + } if (!NewTSI) return nullptr; diff --git a/clang/test/SemaTemplate/nested-implicit-deduction-guides-crash.cpp b/clang/test/SemaTemplate/nested-implicit-deduction-guides-crash.cpp new file mode 100644 index 0000000000000..66be88b495d69 --- /dev/null +++ b/clang/test/SemaTemplate/nested-implicit-deduction-guides-crash.cpp @@ -0,0 +1,22 @@ +// RUN: %clang_cc1 -std=c++20 -fsyntax-only -verify %s + +template <typename, typename> +class C { +public: + template <typename> + class C2 { // expected-note {{candidate template ignored}} \ + // expected-note {{implicit deduction guide declared as}} + public: + C2(C &) {} // expected-note {{candidate template ignored}} \ + // expected-note {{implicit deduction guide declared as}} + }; + + void f() { + C2(*this); // expected-error {{no viable constructor or deduction guide}} + } +}; + +int main() { + C<int, int>().f(); // expected-note {{in instantiation of member function}} + return 0; +} `````````` </details> https://github.com/llvm/llvm-project/pull/207644 _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
