Author: Nikolas Klauser Date: 2025-08-18T07:49:47+02:00 New Revision: 83f21507171a5b121fe8dad37de21701b5720ca1
URL: https://github.com/llvm/llvm-project/commit/83f21507171a5b121fe8dad37de21701b5720ca1 DIFF: https://github.com/llvm/llvm-project/commit/83f21507171a5b121fe8dad37de21701b5720ca1.diff LOG: [libc++] Fix std::variant evaluating template arguments too eagerly (#151028) This has been reported in https://github.com/llvm/llvm-project/pull/116709#issuecomment-3105095648. Fixes #151328 (cherry picked from commit f5f582451e913581ef214b8b771a13d3912394d5) Added: Modified: libcxx/include/__type_traits/invoke.h libcxx/test/std/utilities/variant/variant.variant/variant.ctor/T.pass.cpp Removed: ################################################################################ diff --git a/libcxx/include/__type_traits/invoke.h b/libcxx/include/__type_traits/invoke.h index 5ff2efbe5faaf..3f5626c014432 100644 --- a/libcxx/include/__type_traits/invoke.h +++ b/libcxx/include/__type_traits/invoke.h @@ -67,20 +67,20 @@ _LIBCPP_BEGIN_NAMESPACE_STD #if __has_builtin(__builtin_invoke) -template <class... _Args> -using __invoke_result_t _LIBCPP_NODEBUG = decltype(__builtin_invoke(std::declval<_Args>()...)); - template <class, class... _Args> struct __invoke_result_impl {}; template <class... _Args> -struct __invoke_result_impl<__void_t<__invoke_result_t<_Args...> >, _Args...> { - using type _LIBCPP_NODEBUG = __invoke_result_t<_Args...>; +struct __invoke_result_impl<__void_t<decltype(__builtin_invoke(std::declval<_Args>()...))>, _Args...> { + using type _LIBCPP_NODEBUG = decltype(__builtin_invoke(std::declval<_Args>()...)); }; template <class... _Args> using __invoke_result _LIBCPP_NODEBUG = __invoke_result_impl<void, _Args...>; +template <class... _Args> +using __invoke_result_t _LIBCPP_NODEBUG = typename __invoke_result<_Args...>::type; + template <class... _Args> _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR __invoke_result_t<_Args...> __invoke(_Args&&... __args) _NOEXCEPT_(noexcept(__builtin_invoke(std::forward<_Args>(__args)...))) { diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/T.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/T.pass.cpp index 142da1d820d9a..6111138726dbc 100644 --- a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/T.pass.cpp +++ b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/T.pass.cpp @@ -173,6 +173,11 @@ void test_vector_bool() { assert(std::get<0>(v) == true); } +struct ConvertibleFromAny { + template <class V> + ConvertibleFromAny(V) {} +}; + int main(int, char**) { test_T_ctor_basic(); test_T_ctor_noexcept(); @@ -180,5 +185,16 @@ int main(int, char**) { test_no_narrowing_check_for_class_types(); test_construction_with_repeated_types(); test_vector_bool(); + + { // Check that the constraints are evaluated lazily (see https://github.com/llvm/llvm-project/issues/151328) + struct Matcher { + Matcher() {} + Matcher(std::variant<ConvertibleFromAny>) {} + }; + + Matcher vec; + [[maybe_unused]] Matcher m = std::move(vec); + } + return 0; } _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
