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 // UNSUPPORTED: c++03, c++11, c++14, c++17
10
11 // template<class F, class... Args>
12 // concept strict_weak_order;
13
14 #include <concepts>
15
16 struct S1 {};
17 struct S2 {};
18
19 struct 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 off
27 template<class F, class T, class U>
28 requires std::relation<F, T, U>
check_strict_weak_order_subsumes_relation()29 constexpr bool check_strict_weak_order_subsumes_relation() {
30 return false;
31 }
32
33 template<class F, class T, class U>
34 requires std::strict_weak_order<F, T, U> && true
check_strict_weak_order_subsumes_relation()35 constexpr bool check_strict_weak_order_subsumes_relation() {
36 return true;
37 }
38 // clang-format on
39
40 static_assert(check_strict_weak_order_subsumes_relation<int (*)(int, int), int, int>());
41 static_assert(check_strict_weak_order_subsumes_relation<int (*)(int, double), int, double>());
42 static_assert(check_strict_weak_order_subsumes_relation<R, S1, S1>());
43 static_assert(check_strict_weak_order_subsumes_relation<R, S1, S2>());
44
45 // clang-format off
46 template<class F, class T, class U>
47 requires std::relation<F, T, U> && true
check_relation_subsumes_strict_weak_order()48 constexpr bool check_relation_subsumes_strict_weak_order() {
49 return true;
50 }
51
52 template<class F, class T, class U>
53 requires std::strict_weak_order<F, T, U>
check_relation_subsumes_strict_weak_order()54 constexpr bool check_relation_subsumes_strict_weak_order() {
55 return false;
56 }
57 // clang-format on
58
59 static_assert(check_relation_subsumes_strict_weak_order<int (*)(int, int), int, int>());
60 static_assert(check_relation_subsumes_strict_weak_order<int (*)(int, double), int, double>());
61 static_assert(check_relation_subsumes_strict_weak_order<R, S1, S1>());
62 static_assert(check_relation_subsumes_strict_weak_order<R, S1, S2>());
63
64 // clang-format off
65 template<class F, class T, class U>
66 requires std::strict_weak_order<F, T, T> && std::strict_weak_order<F, U, U>
check_strict_weak_order_subsumes_itself()67 constexpr bool check_strict_weak_order_subsumes_itself() {
68 return false;
69 }
70
71 template<class F, class T, class U>
72 requires std::strict_weak_order<F, T, U>
check_strict_weak_order_subsumes_itself()73 constexpr bool check_strict_weak_order_subsumes_itself() {
74 return true;
75 }
76 // clang-format on
77
78 static_assert(check_strict_weak_order_subsumes_itself<int (*)(int, int), int, int>());
79 static_assert(check_strict_weak_order_subsumes_itself<R, S1, S1>());
80