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, c++20 |
10 | |
11 | // constexpr void swap(unexpected& other) noexcept(is_nothrow_swappable_v<E>); |
12 | // |
13 | // Mandates: is_swappable_v<E> is true. |
14 | // |
15 | // Effects: Equivalent to: using std::swap; swap(unex, other.unex); |
16 | |
17 | #include <cassert> |
18 | #include <concepts> |
19 | #include <expected> |
20 | #include <utility> |
21 | |
22 | // test noexcept |
23 | struct NoexceptSwap { |
24 | friend void swap(NoexceptSwap&, NoexceptSwap&) noexcept; |
25 | }; |
26 | |
27 | struct MayThrowSwap { |
28 | friend void swap(MayThrowSwap&, MayThrowSwap&); |
29 | }; |
30 | |
31 | template <class T> |
32 | concept MemberSwapNoexcept = |
33 | requires(T& t1, T& t2) { |
34 | { t1.swap(t2) } noexcept; |
35 | }; |
36 | |
37 | static_assert(MemberSwapNoexcept<std::unexpected<NoexceptSwap>>); |
38 | static_assert(!MemberSwapNoexcept<std::unexpected<MayThrowSwap>>); |
39 | |
40 | struct ADLSwap { |
41 | constexpr ADLSwap(int ii) : i(ii) {} |
42 | ADLSwap& operator=(const ADLSwap&) = delete; |
43 | int i; |
44 | constexpr friend void swap(ADLSwap& x, ADLSwap& y) { std::swap(a&: x.i, b&: y.i); } |
45 | }; |
46 | |
47 | constexpr bool test() { |
48 | // using std::swap; |
49 | { |
50 | std::unexpected<int> unex1(5); |
51 | std::unexpected<int> unex2(6); |
52 | unex1.swap(unex2); |
53 | assert(unex1.error() == 6); |
54 | assert(unex2.error() == 5); |
55 | } |
56 | |
57 | // adl swap |
58 | { |
59 | std::unexpected<ADLSwap> unex1(5); |
60 | std::unexpected<ADLSwap> unex2(6); |
61 | unex1.swap(unex2); |
62 | assert(unex1.error().i == 6); |
63 | assert(unex2.error().i == 5); |
64 | } |
65 | return true; |
66 | } |
67 | |
68 | int main(int, char**) { |
69 | test(); |
70 | static_assert(test()); |
71 | return 0; |
72 | } |
73 | |