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_REFERENCE_WITH_H
10#define _LIBCPP___CONCEPTS_COMMON_REFERENCE_WITH_H
11
12#include <__concepts/convertible_to.h>
13#include <__concepts/same_as.h>
14#include <__config>
15#include <__type_traits/common_reference.h>
16
17#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
18# pragma GCC system_header
19#endif
20
21_LIBCPP_BEGIN_NAMESPACE_STD
22
23#if _LIBCPP_STD_VER >= 20
24
25// [concept.commonref]
26
27template <class _Tp, class _Up>
28concept common_reference_with =
29 same_as<common_reference_t<_Tp, _Up>, common_reference_t<_Up, _Tp>> &&
30 convertible_to<_Tp, common_reference_t<_Tp, _Up>> && convertible_to<_Up, common_reference_t<_Tp, _Up>>;
31
32#endif // _LIBCPP_STD_VER >= 20
33
34_LIBCPP_END_NAMESPACE_STD
35
36#endif // _LIBCPP___CONCEPTS_COMMON_REFERENCE_WITH_H
37