https://github.com/cor3ntin created https://github.com/llvm/llvm-project/pull/138121
When a lambda is used in an alias declaration, we were trying to refer to its call operator. However, that could happen before (or during) the call operator is defined. So we should not assume a lambda always has a call operator. Fixes #136432 Fixes #137014 Fixes #138018 >From 34011def1ec643701a84424f0813484efa39a1d1 Mon Sep 17 00:00:00 2001 From: Corentin Jabot <corentinja...@gmail.com> Date: Thu, 1 May 2025 13:32:00 +0200 Subject: [PATCH] [Clang] incorrect assertion when checking template template parameter of a lambda. When a lamdbda is used in an alias declaration, we were trying to refer to its call operator. However, that could happen before (or during) the call operator is defined. So we should not assume a lambda always has a call operator. Fixes #136432 Fixes #137014 Fixes #138018 --- clang/docs/ReleaseNotes.rst | 2 ++ clang/lib/AST/DeclCXX.cpp | 6 +++++- clang/test/SemaCXX/lambda-unevaluated.cpp | 16 ++++++++++++++++ 3 files changed, 23 insertions(+), 1 deletion(-) diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index f5cd1fbeabcfe..8a463f9aca0c9 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -529,6 +529,8 @@ Bug Fixes to C++ Support - Clang now issues an error when placement new is used to modify a const-qualified variable in a ``constexpr`` function. (#GH131432) - Clang now emits a warning when class template argument deduction for alias templates is used in C++17. (#GH133806) +- Fix a crash when checking the template template parameters of a dependent lambda appearing in an alias declaration. + (#GH136432), (#GH137014), (#GH138018) Bug Fixes to AST Handling ^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/clang/lib/AST/DeclCXX.cpp b/clang/lib/AST/DeclCXX.cpp index 4d07efd58f518..9095575ee1175 100644 --- a/clang/lib/AST/DeclCXX.cpp +++ b/clang/lib/AST/DeclCXX.cpp @@ -1696,7 +1696,11 @@ static NamedDecl* getLambdaCallOperatorHelper(const CXXRecordDecl &RD) { RD.getASTContext().DeclarationNames.getCXXOperatorName(OO_Call); DeclContext::lookup_result Calls = RD.lookup(Name); - assert(!Calls.empty() && "Missing lambda call operator!"); + + // This can happen while building the lambda. + if (Calls.empty()) + return nullptr; + assert(allLookupResultsAreTheSame(Calls) && "More than one lambda call operator!"); diff --git a/clang/test/SemaCXX/lambda-unevaluated.cpp b/clang/test/SemaCXX/lambda-unevaluated.cpp index a9bcab58464e2..40f8a729fd912 100644 --- a/clang/test/SemaCXX/lambda-unevaluated.cpp +++ b/clang/test/SemaCXX/lambda-unevaluated.cpp @@ -266,3 +266,19 @@ void func() { } } // namespace GH88081 + +namespace GH138018 { + +template <typename T> struct vec {}; + +auto structure_to_typelist(auto) { + return []<template <typename> typename T>(T<int>) { + return 0; + }(vec<int>{}); +} + +template <typename T> using helper = decltype(structure_to_typelist(T{})); +static_assert(__is_same_as(int, helper<int>)); + + +} // namespace GH138018 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits