| 1 | //===----------------------------------------------------------------------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | // UNSUPPORTED: c++03, c++11, c++14, c++17 |
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| 10 | |
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| 11 | // template<class F, class... Args> |
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| 12 | // concept equivalence_relation; |
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| 13 | |
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| 14 | #include <concepts> |
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| 15 | |
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| 16 | struct S1 {}; |
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| 17 | struct S2 {}; |
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| 18 | |
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| 19 | struct R { |
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| 20 | bool operator()(S1, S1) const; |
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| 21 | bool operator()(S1, S2) const; |
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| 22 | bool operator()(S2, S1) const; |
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| 23 | bool operator()(S2, S2) const; |
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| 24 | }; |
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| 25 | |
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| 26 | // clang-format off |
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| 27 | template<class F, class T, class U> |
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| 28 | requires std::relation<F, T, U> |
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| 29 | constexpr bool check_equivalence_relation_subsumes_relation() { |
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| 30 | return false; |
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| 31 | } |
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| 32 | |
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| 33 | template<class F, class T, class U> |
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| 34 | requires std::equivalence_relation<F, T, U> && true |
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| 35 | constexpr bool check_equivalence_relation_subsumes_relation() { |
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| 36 | return true; |
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| 37 | } |
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| 38 | // clang-format on |
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| 39 | |
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| 40 | static_assert(check_equivalence_relation_subsumes_relation<int (*)(int, int), int, int>()); |
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| 41 | static_assert(check_equivalence_relation_subsumes_relation<int (*)(int, double), int, double>()); |
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| 42 | static_assert(check_equivalence_relation_subsumes_relation<R, S1, S1>()); |
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| 43 | static_assert(check_equivalence_relation_subsumes_relation<R, S1, S2>()); |
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| 44 | |
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| 45 | // clang-format off |
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| 46 | template<class F, class T, class U> |
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| 47 | requires std::relation<F, T, U> && true |
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| 48 | constexpr bool check_relation_subsumes_equivalence_relation() { |
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| 49 | return true; |
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| 50 | } |
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| 51 | |
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| 52 | template<class F, class T, class U> |
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| 53 | requires std::equivalence_relation<F, T, U> |
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| 54 | constexpr bool check_relation_subsumes_equivalence_relation() { |
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| 55 | return false; |
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| 56 | } |
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| 57 | // clang-format on |
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| 58 | |
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| 59 | static_assert(check_relation_subsumes_equivalence_relation<int (*)(int, int), int, int>()); |
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| 60 | static_assert(check_relation_subsumes_equivalence_relation<int (*)(int, double), int, double>()); |
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| 61 | static_assert(check_relation_subsumes_equivalence_relation<R, S1, S1>()); |
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| 62 | static_assert(check_relation_subsumes_equivalence_relation<R, S1, S2>()); |
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| 63 | |
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| 64 | // clang-format off |
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| 65 | template<class F, class T, class U> |
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| 66 | requires std::equivalence_relation<F, T, T> && std::equivalence_relation<F, U, U> |
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| 67 | constexpr bool check_equivalence_relation_subsumes_itself() { |
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| 68 | return false; |
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| 69 | } |
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| 70 | |
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| 71 | template<class F, class T, class U> |
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| 72 | requires std::equivalence_relation<F, T, U> |
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| 73 | constexpr bool check_equivalence_relation_subsumes_itself() { |
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| 74 | return true; |
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| 75 | } |
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| 76 | // clang-format on |
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| 77 | |
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| 78 | static_assert( |
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| 79 | check_equivalence_relation_subsumes_itself<int (*)(int, int), int, int>()); |
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| 80 | static_assert(check_equivalence_relation_subsumes_itself<R, S1, S1>()); |
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| 81 | |
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