81 lines · cpp
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// UNSUPPORTED: c++03, c++11, c++14, c++1710 11// template<class F, class... Args>12// concept equivalence_relation;13 14#include <concepts>15 16struct S1 {};17struct S2 {};18 19struct R {20 bool operator()(S1, S1) const;21 bool operator()(S1, S2) const;22 bool operator()(S2, S1) const;23 bool operator()(S2, S2) const;24};25 26// clang-format off27template<class F, class T, class U>28requires std::relation<F, T, U>29constexpr bool check_equivalence_relation_subsumes_relation() {30 return false;31}32 33template<class F, class T, class U>34requires std::equivalence_relation<F, T, U> && true35constexpr bool check_equivalence_relation_subsumes_relation() {36 return true;37}38// clang-format on39 40static_assert(check_equivalence_relation_subsumes_relation<int (*)(int, int), int, int>());41static_assert(check_equivalence_relation_subsumes_relation<int (*)(int, double), int, double>());42static_assert(check_equivalence_relation_subsumes_relation<R, S1, S1>());43static_assert(check_equivalence_relation_subsumes_relation<R, S1, S2>());44 45// clang-format off46template<class F, class T, class U>47requires std::relation<F, T, U> && true48constexpr bool check_relation_subsumes_equivalence_relation() {49 return true;50}51 52template<class F, class T, class U>53requires std::equivalence_relation<F, T, U>54constexpr bool check_relation_subsumes_equivalence_relation() {55 return false;56}57// clang-format on58 59static_assert(check_relation_subsumes_equivalence_relation<int (*)(int, int), int, int>());60static_assert(check_relation_subsumes_equivalence_relation<int (*)(int, double), int, double>());61static_assert(check_relation_subsumes_equivalence_relation<R, S1, S1>());62static_assert(check_relation_subsumes_equivalence_relation<R, S1, S2>());63 64// clang-format off65template<class F, class T, class U>66requires std::equivalence_relation<F, T, T> && std::equivalence_relation<F, U, U>67constexpr bool check_equivalence_relation_subsumes_itself() {68 return false;69}70 71template<class F, class T, class U>72requires std::equivalence_relation<F, T, U>73constexpr bool check_equivalence_relation_subsumes_itself() {74 return true;75}76// clang-format on77 78static_assert(79 check_equivalence_relation_subsumes_itself<int (*)(int, int), int, int>());80static_assert(check_equivalence_relation_subsumes_itself<R, S1, S1>());81