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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-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef _LIBCPP___CONCEPTS_EQUALITY_COMPARABLE_H10#define _LIBCPP___CONCEPTS_EQUALITY_COMPARABLE_H11 12#include <__concepts/boolean_testable.h>13#include <__concepts/common_reference_with.h>14#include <__config>15#include <__type_traits/common_reference.h>16#include <__type_traits/make_const_lvalue_ref.h>17 18#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)19# pragma GCC system_header20#endif21 22_LIBCPP_BEGIN_NAMESPACE_STD23 24#if _LIBCPP_STD_VER >= 2025 26// [concept.equalitycomparable]27 28template <class _Tp, class _Up>29concept __weakly_equality_comparable_with =30 requires(__make_const_lvalue_ref<_Tp> __t, __make_const_lvalue_ref<_Up> __u) {31 { __t == __u } -> __boolean_testable;32 { __t != __u } -> __boolean_testable;33 { __u == __t } -> __boolean_testable;34 { __u != __t } -> __boolean_testable;35 };36 37template <class _Tp>38concept equality_comparable = __weakly_equality_comparable_with<_Tp, _Tp>;39 40// clang-format off41template <class _Tp, class _Up>42concept equality_comparable_with =43 equality_comparable<_Tp> && equality_comparable<_Up> &&44 common_reference_with<__make_const_lvalue_ref<_Tp>, __make_const_lvalue_ref<_Up>> &&45 equality_comparable<46 common_reference_t<47 __make_const_lvalue_ref<_Tp>,48 __make_const_lvalue_ref<_Up>>> &&49 __weakly_equality_comparable_with<_Tp, _Up>;50// clang-format on51 52#endif // _LIBCPP_STD_VER >= 2053 54_LIBCPP_END_NAMESPACE_STD55 56#endif // _LIBCPP___CONCEPTS_EQUALITY_COMPARABLE_H57