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 T>
12// concept swappable = // see below
13
14#include <concepts>
15
16#include <algorithm>
17#include <cassert>
18#include <deque>
19#include <map>
20#include <memory>
21#include <string>
22#include <optional>
23#include <unordered_map>
24#include <vector>
25
26#include "test_macros.h"
27#include "type_classification/moveconstructible.h"
28#include "type_classification/swappable.h"
29
30template <class T>
31struct expected {
32 T x;
33 T y;
34};
35
36// clang-format off
37// Checks [concept.swappable]/2.1
38template <class T, class U>
39requires std::same_as<std::remove_cvref_t<T>, std::remove_cvref_t<U> > &&
40 std::swappable<std::remove_cvref_t<T> >
41constexpr bool check_swap_21(T&& x, U&& y) {
42 expected<std::remove_cvref_t<T> > const e{y, x};
43 std::ranges::swap(std::forward<T>(x), std::forward<U>(y));
44 return x == e.x && y == e.y;
45}
46
47// Checks [concept.swappable]/2.2
48template <std::swappable T, std::size_t N>
49constexpr bool check_swap_22(T (&x)[N], T (&y)[N]) {
50 expected<T[N]> e;
51 std::copy(y, y + N, e.x);
52 std::copy(x, x + N, e.y);
53
54 std::ranges::swap(x, y);
55 return std::equal(x, x + N, e.x, e.x + N) &&
56 std::equal(y, y + N, e.y, e.y + N);
57}
58
59// Checks [concept.swappable]/2.3
60template <std::swappable T>
61requires std::copy_constructible<std::remove_cvref_t<T> >
62constexpr bool check_swap_23(T x, T y) {
63 expected<std::remove_cvref_t<T> > const e{y, x};
64 std::ranges::swap(x, y);
65 return x == e.x && y == e.y;
66}
67// clang-format on
68
69constexpr bool check_lvalue_adl_swappable() {
70 auto x = lvalue_adl_swappable(0);
71 auto y = lvalue_adl_swappable(1);
72 ASSERT_NOEXCEPT(std::ranges::swap(x, y));
73 assert(check_swap_21(x, y));
74 return true;
75}
76static_assert(check_lvalue_adl_swappable());
77
78constexpr bool check_rvalue_adl_swappable() {
79 ASSERT_NOEXCEPT(std::ranges::swap(rvalue_adl_swappable(0), rvalue_adl_swappable(1)));
80 assert(check_swap_21(rvalue_adl_swappable(0), rvalue_adl_swappable(1)));
81 return true;
82}
83static_assert(check_rvalue_adl_swappable());
84
85constexpr bool check_lvalue_rvalue_adl_swappable() {
86 auto x = lvalue_rvalue_adl_swappable(0);
87 ASSERT_NOEXCEPT(std::ranges::swap(x, lvalue_rvalue_adl_swappable(1)));
88 assert(check_swap_21(x, lvalue_rvalue_adl_swappable(1)));
89 return true;
90}
91static_assert(check_lvalue_rvalue_adl_swappable());
92
93constexpr bool check_rvalue_lvalue_adl_swappable() {
94 auto x = rvalue_lvalue_adl_swappable(0);
95 ASSERT_NOEXCEPT(std::ranges::swap(rvalue_lvalue_adl_swappable(1), x));
96 assert(check_swap_21(rvalue_lvalue_adl_swappable(1), x));
97 return true;
98}
99static_assert(check_rvalue_lvalue_adl_swappable());
100
101constexpr bool check_throwable_swappable() {
102 auto x = throwable_adl_swappable{0};
103 auto y = throwable_adl_swappable{1};
104 ASSERT_NOT_NOEXCEPT(std::ranges::swap(x, y));
105 assert(check_swap_21(x, y));
106 return true;
107}
108static_assert(check_throwable_swappable());
109
110constexpr bool check_non_move_constructible_adl_swappable() {
111 auto x = non_move_constructible_adl_swappable{0};
112 auto y = non_move_constructible_adl_swappable{1};
113 ASSERT_NOEXCEPT(std::ranges::swap(x, y));
114 assert(check_swap_21(x, y));
115 return true;
116}
117static_assert(check_non_move_constructible_adl_swappable());
118
119constexpr bool check_non_move_assignable_adl_swappable() {
120 auto x = non_move_assignable_adl_swappable{0};
121 auto y = non_move_assignable_adl_swappable{1};
122 ASSERT_NOEXCEPT(std::ranges::swap(x, y));
123 assert(check_swap_21(x, y));
124 return true;
125}
126static_assert(check_non_move_assignable_adl_swappable());
127
128namespace swappable_namespace {
129enum unscoped { hello, world };
130void swap(unscoped&, unscoped&);
131
132enum class scoped { hello, world };
133void swap(scoped&, scoped&);
134} // namespace swappable_namespace
135
136static_assert(std::swappable<swappable_namespace::unscoped>);
137static_assert(std::swappable<swappable_namespace::scoped>);
138
139constexpr bool check_swap_arrays() {
140 int x[] = {0, 1, 2, 3, 4};
141 int y[] = {5, 6, 7, 8, 9};
142 ASSERT_NOEXCEPT(std::ranges::swap(x, y));
143 assert(check_swap_22(x, y));
144 return true;
145}
146static_assert(check_swap_arrays());
147
148constexpr bool check_lvalue_adl_swappable_arrays() {
149 lvalue_adl_swappable x[] = {{0}, {1}, {2}, {3}};
150 lvalue_adl_swappable y[] = {{4}, {5}, {6}, {7}};
151 ASSERT_NOEXCEPT(std::ranges::swap(x, y));
152 assert(check_swap_22(x, y));
153 return true;
154}
155static_assert(check_lvalue_adl_swappable_arrays());
156
157constexpr bool check_throwable_adl_swappable_arrays() {
158 throwable_adl_swappable x[] = {{0}, {1}, {2}, {3}};
159 throwable_adl_swappable y[] = {{4}, {5}, {6}, {7}};
160 ASSERT_NOT_NOEXCEPT(std::ranges::swap(x, y));
161 assert(check_swap_22(x, y));
162 return true;
163}
164static_assert(check_throwable_adl_swappable_arrays());
165
166auto global_x = 0;
167ASSERT_NOEXCEPT(std::ranges::swap(global_x, global_x));
168static_assert(check_swap_23(0, 0));
169static_assert(check_swap_23(0, 1));
170static_assert(check_swap_23(1, 0));
171
172constexpr bool check_swappable_references() {
173 int x = 42;
174 int y = 64;
175 ASSERT_NOEXCEPT(std::ranges::swap(x, y));
176 assert(check_swap_23(x, y));
177 return true;
178}
179static_assert(check_swappable_references());
180
181constexpr bool check_swappable_pointers() {
182 char const* x = "hello";
183 ASSERT_NOEXCEPT(std::ranges::swap(x, x));
184 assert(check_swap_23(x, {}));
185 return true;
186}
187static_assert(check_swappable_pointers());
188
189namespace union_swap {
190union adl_swappable {
191 int x;
192 double y;
193};
194
195void swap(adl_swappable&, adl_swappable&);
196void swap(adl_swappable&&, adl_swappable&&);
197} // namespace union_swap
198static_assert(std::swappable<union_swap::adl_swappable>);
199static_assert(std::swappable<union_swap::adl_swappable&>);
200static_assert(std::swappable<union_swap::adl_swappable&&>);
201
202// All tests for std::swappable<T> are implicitly confirmed by `check_swap`, so we only need to
203// sanity check for a few positive cases.
204static_assert(std::swappable<int volatile&>);
205static_assert(std::swappable<int&&>);
206static_assert(std::swappable<int (*)()>);
207static_assert(std::swappable<int rvalue_adl_swappable::*>);
208static_assert(std::swappable<int (rvalue_adl_swappable::*)()>);
209static_assert(std::swappable<std::unique_ptr<int> >);
210
211static_assert(!std::swappable<void>);
212static_assert(!std::swappable<int const>);
213static_assert(!std::swappable<int const&>);
214static_assert(!std::swappable<int const&&>);
215static_assert(!std::swappable<int const volatile>);
216static_assert(!std::swappable<int const volatile&>);
217static_assert(!std::swappable<int const volatile&&>);
218static_assert(!std::swappable<int (&)()>);
219static_assert(!std::swappable<DeletedMoveCtor>);
220static_assert(!std::swappable<ImplicitlyDeletedMoveCtor>);
221static_assert(!std::swappable<DeletedMoveAssign>);
222static_assert(!std::swappable<ImplicitlyDeletedMoveAssign>);
223static_assert(!std::swappable<NonMovable>);
224static_assert(!std::swappable<DerivedFromNonMovable>);
225static_assert(!std::swappable<HasANonMovable>);
226
227using swap_type = std::remove_const_t<decltype(std::ranges::swap)>;
228static_assert(std::default_initializable<swap_type>);
229static_assert(std::move_constructible<swap_type>);
230static_assert(std::copy_constructible<swap_type>);
231static_assert(std::assignable_from<swap_type&, swap_type>);
232static_assert(std::assignable_from<swap_type&, swap_type&>);
233static_assert(std::assignable_from<swap_type&, swap_type const&>);
234static_assert(std::assignable_from<swap_type&, swap_type const>);
235static_assert(std::swappable<swap_type>);
236
237enum class nothrow { no, yes };
238
239template <nothrow is_noexcept, std::swappable T>
240void check_swap(expected<T> const& e) {
241 auto a = e.y;
242 auto b = e.x;
243
244 std::ranges::swap(a, b);
245 assert(a == e.x);
246 assert(b == e.y);
247
248 std::ranges::swap(a, b);
249 assert(a == e.y);
250 assert(b == e.x);
251
252 static_assert(noexcept(std::ranges::swap(a, b)) == bool(is_noexcept));
253}
254
255int main(int, char**) {
256 {
257 auto const e = expected<std::deque<int> >{
258 .x = {6, 7, 8, 9},
259 .y = {0, 1, 2, 3, 4, 5},
260 };
261 check_swap<nothrow::yes>(e);
262 }
263 {
264 auto const e = expected<std::map<int, std::string> >{
265 .x = {{0, "whole"}, {1, "cashews"}},
266 .y = {{-1, "roasted"}, {2, "&"}, {-3, "salted"}},
267 };
268 check_swap<nothrow::yes>(e);
269 }
270 {
271 auto const e = expected<std::string>{
272 .x = "hello there",
273 .y = "general kenobi",
274 };
275 check_swap<nothrow::yes>(e);
276 }
277 {
278 auto const e = expected<std::optional<lvalue_adl_swappable> >{
279 .x = {10},
280 .y = {20},
281 };
282 check_swap<nothrow::yes>(e);
283 }
284 {
285 auto const e = expected<std::optional<throwable_adl_swappable> >{
286 .x = {10},
287 .y = {20},
288 };
289 check_swap<nothrow::no>(e);
290 }
291 {
292 auto const e = expected<std::unordered_map<int, std::string> >{
293 .x = {{0, "whole"}, {1, "cashews"}},
294 .y = {{-1, "roasted"}, {2, "&"}, {-3, "salted"}},
295 };
296 check_swap<nothrow::yes>(e);
297 }
298 {
299 auto const e = expected<std::vector<int> >{
300 .x = {0, 1, 2, 3, 4, 5},
301 .y = {6, 7, 8, 9},
302 };
303
304 check_swap<nothrow::yes>(e);
305 }
306 return 0;
307}
308

source code of libcxx/test/std/concepts/concepts.lang/concept.swappable/swappable.pass.cpp