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
29 template <class T>
30 struct some_alloc {
31 typedef T value_type;
32 some_alloc(const some_alloc&);
33 T* allocate(std::size_t);
34 };
35
36 template <class T>
37 struct some_alloc2 {
38 typedef T value_type;
39
some_alloc2some_alloc240 some_alloc2() {}
41 some_alloc2(const some_alloc2&);
42 T* allocate(std::size_t);
deallocatesome_alloc243 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
49 template <class T>
50 struct some_alloc3 {
51 typedef T value_type;
52
some_alloc3some_alloc353 some_alloc3() {}
54 some_alloc3(const some_alloc3&);
55 T* allocate(std::size_t);
deallocatesome_alloc356 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
test()62 TEST_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
main(int,char **)96 int main(int, char**) {
97 test();
98 #if TEST_STD_VER > 17
99 static_assert(test());
100 #endif
101
102 return 0;
103 }
104