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 equivalence_relation;
13 
14 #include <concepts>
15 
16 static_assert(std::equivalence_relation<bool(int, int), int, int>);
17 static_assert(std::equivalence_relation<bool(int, int), double, double>);
18 static_assert(std::equivalence_relation<bool(int, double), double, double>);
19 
20 static_assert(!std::equivalence_relation<bool (*)(), int, double>);
21 static_assert(!std::equivalence_relation<bool (*)(int), int, double>);
22 static_assert(!std::equivalence_relation<bool (*)(double), int, double>);
23 
24 static_assert(
25     !std::equivalence_relation<bool(double, double*), double, double*>);
26 static_assert(!std::equivalence_relation<bool(int&, int&), double&, double&>);
27 
28 struct S1 {};
29 static_assert(std::relation<bool (S1::*)(S1*), S1*, S1*>);
30 static_assert(std::relation<bool (S1::*)(S1&), S1&, S1&>);
31 
32 struct S2 {};
33 
34 struct P1 {
35   bool operator()(S1, S1) const;
36 };
37 static_assert(std::equivalence_relation<P1, S1, S1>);
38 
39 struct P2 {
40   bool operator()(S1, S1) const;
41   bool operator()(S1, S2) const;
42 };
43 static_assert(!std::equivalence_relation<P2, S1, S2>);
44 
45 struct P3 {
46   bool operator()(S1, S1) const;
47   bool operator()(S1, S2) const;
48   bool operator()(S2, S1) const;
49 };
50 static_assert(!std::equivalence_relation<P3, S1, S2>);
51 
52 struct P4 {
53   bool operator()(S1, S1) const;
54   bool operator()(S1, S2) const;
55   bool operator()(S2, S1) const;
56   bool operator()(S2, S2) const;
57 };
58 static_assert(std::equivalence_relation<P4, S1, S2>);
59