diff --git a/libcxx/include/__functional/identity.h b/libcxx/include/__functional/identity.h index 1b1c6cf73c378..02dde2b4f323d 100644 --- a/libcxx/include/__functional/identity.h +++ b/libcxx/include/__functional/identity.h @@ -44,7 +44,7 @@ struct __is_identity > : true_type {}; struct identity { template - [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp&& operator()(_Tp&& __t) const noexcept { + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Tp&& operator()(_LIBCPP_LIFETIMEBOUND _Tp&& __t) const noexcept { return std::forward<_Tp>(__t); } diff --git a/libcxx/test/libcxx/utilities/function.objects/lifetimebound.verify.cpp b/libcxx/test/libcxx/utilities/function.objects/lifetimebound.verify.cpp new file mode 100644 index 0000000000000..5c66bc11fca4c --- /dev/null +++ b/libcxx/test/libcxx/utilities/function.objects/lifetimebound.verify.cpp @@ -0,0 +1,20 @@ +//===----------------------------------------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +// UNSUPPORTED: c++03, c++11, c++14, c++17 +// ADDITIONAL_COMPILE_FLAGS: -Wno-pessimizing-move -Wno-unused-variable + +#include + +#include "test_macros.h" + +// clang-format off + +void func() { + auto&& v1 = std::identity()(1); // expected-warning {{temporary bound to local reference 'v1' will be destroyed at the end of the full-expression}} +}