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 31 template <class _Tp, class _Up> 32 concept 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