1 //===----------------------------------------------------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 // UNSUPPORTED: c++98, c++03, c++11, c++14
11
12 // type_traits
13
14 // is_swappable
15
16 #include <type_traits>
17 #include <vector>
18 #include "test_macros.h"
19
20 namespace MyNS {
21
22 // Make the test types non-copyable so that generic std::swap is not valid.
23 struct A {
24 A(A const&) = delete;
25 A& operator=(A const&) = delete;
26 };
27
28 struct B {
29 B(B const&) = delete;
30 B& operator=(B const&) = delete;
31 };
32
swap(A &,A &)33 void swap(A&, A&) noexcept {}
swap(B &,B &)34 void swap(B&, B&) {}
35
36 struct M {
37 M(M const&) = delete;
38 M& operator=(M const&) = delete;
39 };
40
swap(M &&,M &&)41 void swap(M&&, M&&) noexcept {}
42
43 struct ThrowingMove {
ThrowingMoveMyNS::ThrowingMove44 ThrowingMove(ThrowingMove&&) {}
operator =MyNS::ThrowingMove45 ThrowingMove& operator=(ThrowingMove&&) { return *this; }
46 };
47
48 } // namespace MyNS
49
main()50 int main()
51 {
52 using namespace MyNS;
53 {
54 // Test that is_swappable applies an lvalue reference to the type.
55 static_assert(std::is_nothrow_swappable<int>::value, "");
56 static_assert(std::is_nothrow_swappable<int&>::value, "");
57 static_assert(!std::is_nothrow_swappable<M>::value, "");
58 static_assert(!std::is_nothrow_swappable<M&&>::value, "");
59 }
60 {
61 // Test that it correctly deduces the noexcept of swap.
62 static_assert(std::is_nothrow_swappable<A>::value, "");
63 static_assert(!std::is_nothrow_swappable<B>::value
64 && std::is_swappable<B>::value, "");
65 static_assert(!std::is_nothrow_swappable<ThrowingMove>::value
66 && std::is_swappable<ThrowingMove>::value, "");
67 }
68 {
69 // Test that it doesn't drop the qualifiers
70 static_assert(!std::is_nothrow_swappable<const A>::value, "");
71 }
72 {
73 // test non-referenceable types
74 static_assert(!std::is_nothrow_swappable<void>::value, "");
75 static_assert(!std::is_nothrow_swappable<int() const>::value, "");
76 static_assert(!std::is_nothrow_swappable<int(int, ...) const &>::value, "");
77 }
78 {
79 // test for presence of is_nothrow_swappable_v
80 static_assert(std::is_nothrow_swappable_v<int>, "");
81 static_assert(!std::is_nothrow_swappable_v<void>, "");
82 }
83 }
84