v1/__concepts/constructible.h

0001 //===----------------------------------------------------------------------===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008
0009 #ifndef _LIBCPP___CONCEPTS_CONSTRUCTIBLE_H
0010 #define _LIBCPP___CONCEPTS_CONSTRUCTIBLE_H
0011
0012 #include <__concepts/convertible_to.h>
0013 #include <__concepts/destructible.h>
0014 #include <__config>
0015 #include <__type_traits/is_constructible.h>
0016
0017 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0018 #  pragma GCC system_header
0019 #endif
0020
0021 _LIBCPP_BEGIN_NAMESPACE_STD
0022
0023 #if _LIBCPP_STD_VER >= 20
0024
0025 // [concept.constructible]
0026 template <class _Tp, class... _Args>
0027 concept constructible_from = destructible<_Tp> && is_constructible_v<_Tp, _Args...>;
0028
0029 // [concept.default.init]
0030
0031 template <class _Tp>
0032 concept __default_initializable = requires { ::new _Tp; };
0033
0034 template <class _Tp>
0035 concept default_initializable = constructible_from<_Tp> && requires { _Tp{}; } && __default_initializable<_Tp>;
0036
0037 // [concept.moveconstructible]
0038 template <class _Tp>
0039 concept move_constructible = constructible_from<_Tp, _Tp> && convertible_to<_Tp, _Tp>;
0040
0041 // [concept.copyconstructible]
0042 // clang-format off
0043 template <class _Tp>
0044 concept copy_constructible =
0045     move_constructible<_Tp> &&
0046     constructible_from<_Tp, _Tp&> && convertible_to<_Tp&, _Tp> &&
0047     constructible_from<_Tp, const _Tp&> && convertible_to<const _Tp&, _Tp> &&
0048     constructible_from<_Tp, const _Tp> && convertible_to<const _Tp, _Tp>;
0049 // clang-format on
0050
0051 #endif // _LIBCPP_STD_VER >= 20
0052
0053 _LIBCPP_END_NAMESPACE_STD
0054
0055 #endif // _LIBCPP___CONCEPTS_CONSTRUCTIBLE_H