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
10
11// <string>
12
13// basic_string& operator=(basic_string&& c)
14// noexcept(
15// allocator_traits<allocator_type>::propagate_on_container_move_assignment::value ||
16// allocator_traits<allocator_type>::is_always_equal::value); // C++17, constexpr since C++20
17//
18// before C++17, we use the conforming extension
19// noexcept(
20// allocator_type::propagate_on_container_move_assignment::value &&
21// is_nothrow_move_assignable<allocator_type>::value); // constexpr since C++20
22
23#include <string>
24#include <cassert>
25
26#include "test_macros.h"
27#include "test_allocator.h"
28
29template <class T>
30struct some_alloc {
31 typedef T value_type;
32 some_alloc(const some_alloc&);
33 T* allocate(std::size_t);
34};
35
36template <class T>
37struct some_alloc2 {
38 typedef T value_type;
39
40 some_alloc2() {}
41 some_alloc2(const some_alloc2&);
42 T* allocate(std::size_t);
43 void deallocate(void*, unsigned) {}
44
45 typedef std::false_type propagate_on_container_move_assignment;
46 typedef std::true_type is_always_equal;
47};
48
49template <class T>
50struct some_alloc3 {
51 typedef T value_type;
52
53 some_alloc3() {}
54 some_alloc3(const some_alloc3&);
55 T* allocate(std::size_t);
56 void deallocate(void*, unsigned) {}
57
58 typedef std::false_type propagate_on_container_move_assignment;
59 typedef std::false_type is_always_equal;
60};
61
62TEST_CONSTEXPR_CXX20 bool test() {
63 {
64 typedef std::string C;
65 static_assert(std::is_nothrow_move_assignable<C>::value, "");
66 }
67 {
68 typedef std::basic_string<char, std::char_traits<char>, test_allocator<char>> C;
69 static_assert(!std::is_nothrow_move_assignable<C>::value, "");
70 }
71 {
72 typedef std::basic_string<char, std::char_traits<char>, some_alloc<char>> C;
73#if TEST_STD_VER > 14
74 // if the allocators are always equal, then the move assignment can be noexcept
75 static_assert(std::is_nothrow_move_assignable<C>::value, "");
76#else
77 static_assert(!std::is_nothrow_move_assignable<C>::value, "");
78#endif
79 }
80#if TEST_STD_VER > 14
81 {
82 // POCMA is false, always equal
83 typedef std::basic_string<char, std::char_traits<char>, some_alloc2<char>> C;
84 static_assert(std::is_nothrow_move_assignable<C>::value, "");
85 }
86 {
87 // POCMA is false, not always equal
88 typedef std::basic_string<char, std::char_traits<char>, some_alloc3<char>> C;
89 static_assert(!std::is_nothrow_move_assignable<C>::value, "");
90 }
91#endif
92
93 return true;
94}
95
96int main(int, char**) {
97 test();
98#if TEST_STD_VER > 17
99 static_assert(test());
100#endif
101
102 return 0;
103}
104

source code of libcxx/test/std/strings/basic.string/string.cons/move_assign_noexcept.pass.cpp