1349cc55cSDimitry Andric //===----------------------------------------------------------------------===// 2349cc55cSDimitry Andric // 3349cc55cSDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4349cc55cSDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 5349cc55cSDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6349cc55cSDimitry Andric // 7349cc55cSDimitry Andric //===----------------------------------------------------------------------===// 8349cc55cSDimitry Andric 9349cc55cSDimitry Andric #ifndef _LIBCPP___CONCEPTS_EQUALITY_COMPARABLE_H 10349cc55cSDimitry Andric #define _LIBCPP___CONCEPTS_EQUALITY_COMPARABLE_H 11349cc55cSDimitry Andric 12349cc55cSDimitry Andric #include <__concepts/boolean_testable.h> 13349cc55cSDimitry Andric #include <__concepts/common_reference_with.h> 14349cc55cSDimitry Andric #include <__config> 15bdd1243dSDimitry Andric #include <__type_traits/common_reference.h> 16bdd1243dSDimitry Andric #include <__type_traits/make_const_lvalue_ref.h> 17349cc55cSDimitry Andric 18349cc55cSDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 19349cc55cSDimitry Andric # pragma GCC system_header 20349cc55cSDimitry Andric #endif 21349cc55cSDimitry Andric 22349cc55cSDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 23349cc55cSDimitry Andric 24*06c3fb27SDimitry Andric #if _LIBCPP_STD_VER >= 20 25349cc55cSDimitry Andric 26349cc55cSDimitry Andric // [concept.equalitycomparable] 27349cc55cSDimitry Andric 28349cc55cSDimitry Andric template <class _Tp, class _Up> 29349cc55cSDimitry Andric concept __weakly_equality_comparable_with = requires(__make_const_lvalue_ref<_Tp> __t,__make_const_lvalue_ref<_Up> __u)30349cc55cSDimitry Andric requires(__make_const_lvalue_ref<_Tp> __t, __make_const_lvalue_ref<_Up> __u) { 31349cc55cSDimitry Andric { __t == __u } -> __boolean_testable; 32349cc55cSDimitry Andric { __t != __u } -> __boolean_testable; 33349cc55cSDimitry Andric { __u == __t } -> __boolean_testable; 34349cc55cSDimitry Andric { __u != __t } -> __boolean_testable; 35349cc55cSDimitry Andric }; 36349cc55cSDimitry Andric 37349cc55cSDimitry Andric template <class _Tp> 38349cc55cSDimitry Andric concept equality_comparable = __weakly_equality_comparable_with<_Tp, _Tp>; 39349cc55cSDimitry Andric 40*06c3fb27SDimitry Andric // clang-format off 41349cc55cSDimitry Andric template <class _Tp, class _Up> 42349cc55cSDimitry Andric concept equality_comparable_with = 43349cc55cSDimitry Andric equality_comparable<_Tp> && equality_comparable<_Up> && 44349cc55cSDimitry Andric common_reference_with<__make_const_lvalue_ref<_Tp>, __make_const_lvalue_ref<_Up>> && 45349cc55cSDimitry Andric equality_comparable< 46349cc55cSDimitry Andric common_reference_t< 47349cc55cSDimitry Andric __make_const_lvalue_ref<_Tp>, 48349cc55cSDimitry Andric __make_const_lvalue_ref<_Up>>> && 49349cc55cSDimitry Andric __weakly_equality_comparable_with<_Tp, _Up>; 50*06c3fb27SDimitry Andric // clang-format on 51349cc55cSDimitry Andric 52*06c3fb27SDimitry Andric #endif // _LIBCPP_STD_VER >= 20 53349cc55cSDimitry Andric 54349cc55cSDimitry Andric _LIBCPP_END_NAMESPACE_STD 55349cc55cSDimitry Andric 56349cc55cSDimitry Andric #endif // _LIBCPP___CONCEPTS_EQUALITY_COMPARABLE_H 57