| // Copyright (C) 2019-2021 Free Software Foundation, Inc. |
| // |
| // This file is part of the GNU ISO C++ Library. This library is free |
| // software; you can redistribute it and/or modify it under the |
| // terms of the GNU General Public License as published by the |
| // Free Software Foundation; either version 3, or (at your option) |
| // any later version. |
| |
| // This library is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // You should have received a copy of the GNU General Public License along |
| // with this library; see the file COPYING3. If not see |
| // <http://www.gnu.org/licenses/>. |
| |
| // { dg-options "-std=gnu++2a" } |
| // { dg-do compile { target c++2a } } |
| |
| #include <functional> |
| |
| // C++20 [func.identity] |
| static_assert( std::is_default_constructible_v<std::identity> ); |
| static_assert( std::is_copy_constructible_v<std::identity> ); |
| static_assert( std::is_move_constructible_v<std::identity> ); |
| static_assert( std::is_copy_assignable_v<std::identity> ); |
| static_assert( std::is_move_assignable_v<std::identity> ); |
| |
| static_assert( !std::is_invocable_v<std::identity> ); |
| static_assert( !std::is_invocable_v<std::identity, int&, int&> ); |
| static_assert( std::is_nothrow_invocable_r_v<int&, std::identity&, int&> ); |
| static_assert( std::is_nothrow_invocable_r_v<const long&, std::identity, const long&> ); |
| static_assert( std::is_nothrow_invocable_r_v<short&&, const std::identity&, short> ); |
| static_assert( std::is_nothrow_invocable_r_v<const char&&, const std::identity, const char> ); |
| |
| int i; |
| static_assert( std::addressof(std::identity{}(i)) == std::addressof(i) ); |
| |
| using T = std::identity::is_transparent; // required typedef |
