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
10
11 // type_traits
12
13 // is_swappable_with
14
15 #include <type_traits>
16 #include <vector>
17 #include "test_macros.h"
18
19 namespace MyNS {
20
21 struct A {
22 A(A const&) = delete;
23 A& operator=(A const&) = delete;
24 };
25
26 struct B {
27 B(B const&) = delete;
28 B& operator=(B const&) = delete;
29 };
30
31 struct C {};
32 struct D {};
33
swap(A &,A &)34 void swap(A&, A&) {}
35
swap(A &,B &)36 void swap(A&, B&) {}
swap(B &,A &)37 void swap(B&, A&) {}
38
swap(A &,C &)39 void swap(A&, C&) {} // missing swap(C, A)
swap(D &,C &)40 void swap(D&, C&) {}
41
42 struct M {};
43
swap(M &&,M &&)44 void swap(M&&, M&&) {}
45
46 } // namespace MyNS
47
main(int,char **)48 int main(int, char**)
49 {
50 using namespace MyNS;
51 {
52 // Test that is_swappable_with doesn't apply an lvalue reference
53 // to the type. Instead it is up to the user.
54 static_assert(!std::is_swappable_with<int, int>::value, "");
55 static_assert(std::is_swappable_with<int&, int&>::value, "");
56 static_assert(std::is_swappable_with<M, M>::value, "");
57 static_assert(std::is_swappable_with<A&, A&>::value, "");
58 }
59 {
60 // test that heterogeneous swap is allowed only if both 'swap(A, B)' and
61 // 'swap(B, A)' are valid.
62 static_assert(std::is_swappable_with<A&, B&>::value, "");
63 static_assert(!std::is_swappable_with<A&, C&>::value, "");
64 static_assert(!std::is_swappable_with<D&, C&>::value, "");
65 }
66 {
67 // test that cv void is guarded against as required.
68 static_assert(!std::is_swappable_with_v<void, int>, "");
69 static_assert(!std::is_swappable_with_v<int, void>, "");
70 static_assert(!std::is_swappable_with_v<const void, const volatile void>, "");
71 }
72 {
73 // test for presence of is_swappable_with_v
74 static_assert(std::is_swappable_with_v<int&, int&>, "");
75 static_assert(!std::is_swappable_with_v<D&, C&>, "");
76 }
77
78 return 0;
79 }
80