1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef _LIBCPP___CONCEPTS_COMMON_WITH_H
10#define _LIBCPP___CONCEPTS_COMMON_WITH_H
11
12#include <__concepts/common_reference_with.h>
13#include <__concepts/same_as.h>
14#include <__config>
15#include <__type_traits/add_lvalue_reference.h>
16#include <__type_traits/common_reference.h>
17#include <__type_traits/common_type.h>
18#include <__utility/declval.h>
19
20#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
21# pragma GCC system_header
22#endif
23
24_LIBCPP_BEGIN_NAMESPACE_STD
25
26#if _LIBCPP_STD_VER >= 20
27
28// [concept.common]
29
30// clang-format off
31template <class _Tp, class _Up>
32concept common_with =
33 same_as<common_type_t<_Tp, _Up>, common_type_t<_Up, _Tp>> &&
34 requires {
35 static_cast<common_type_t<_Tp, _Up>>(std::declval<_Tp>());
36 static_cast<common_type_t<_Tp, _Up>>(std::declval<_Up>());
37 } &&
38 common_reference_with<
39 add_lvalue_reference_t<const _Tp>,
40 add_lvalue_reference_t<const _Up>> &&
41 common_reference_with<
42 add_lvalue_reference_t<common_type_t<_Tp, _Up>>,
43 common_reference_t<
44 add_lvalue_reference_t<const _Tp>,
45 add_lvalue_reference_t<const _Up>>>;
46// clang-format on
47
48#endif // _LIBCPP_STD_VER >= 20
49
50_LIBCPP_END_NAMESPACE_STD
51
52#endif // _LIBCPP___CONCEPTS_COMMON_WITH_H
53