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 > 17 27 28 // [concept.common] 29 30 template<class _Tp, class _Up> 31 concept common_with = 32 same_as<common_type_t<_Tp, _Up>, common_type_t<_Up, _Tp>> && 33 requires { 34 static_cast<common_type_t<_Tp, _Up>>(std::declval<_Tp>()); 35 static_cast<common_type_t<_Tp, _Up>>(std::declval<_Up>()); 36 } && 37 common_reference_with< 38 add_lvalue_reference_t<const _Tp>, 39 add_lvalue_reference_t<const _Up>> && 40 common_reference_with< 41 add_lvalue_reference_t<common_type_t<_Tp, _Up>>, 42 common_reference_t< 43 add_lvalue_reference_t<const _Tp>, 44 add_lvalue_reference_t<const _Up>>>; 45 46 #endif // _LIBCPP_STD_VER > 17 47 48 _LIBCPP_END_NAMESPACE_STD 49 50 #endif // _LIBCPP___CONCEPTS_COMMON_WITH_H 51