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_EQUALITY_COMPARABLE_H 10 #define _LIBCPP___CONCEPTS_EQUALITY_COMPARABLE_H 11 12 #include <__concepts/boolean_testable.h> 13 #include <__concepts/common_reference_with.h> 14 #include <__config> 15 #include <type_traits> 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 !defined(_LIBCPP_HAS_NO_CONCEPTS) 24 25 // [concept.equalitycomparable] 26 27 template<class _Tp, class _Up> 28 concept __weakly_equality_comparable_with = 29 requires(__make_const_lvalue_ref<_Tp> __t, __make_const_lvalue_ref<_Up> __u) { 30 { __t == __u } -> __boolean_testable; 31 { __t != __u } -> __boolean_testable; 32 { __u == __t } -> __boolean_testable; 33 { __u != __t } -> __boolean_testable; 34 }; 35 36 template<class _Tp> 37 concept equality_comparable = __weakly_equality_comparable_with<_Tp, _Tp>; 38 39 template<class _Tp, class _Up> 40 concept equality_comparable_with = 41 equality_comparable<_Tp> && equality_comparable<_Up> && 42 common_reference_with<__make_const_lvalue_ref<_Tp>, __make_const_lvalue_ref<_Up>> && 43 equality_comparable< 44 common_reference_t< 45 __make_const_lvalue_ref<_Tp>, 46 __make_const_lvalue_ref<_Up>>> && 47 __weakly_equality_comparable_with<_Tp, _Up>; 48 49 #endif // !defined(_LIBCPP_HAS_NO_CONCEPTS) 50 51 _LIBCPP_END_NAMESPACE_STD 52 53 #endif // _LIBCPP___CONCEPTS_EQUALITY_COMPARABLE_H 54