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 {
32 typedef T value_type;
33 some_alloc(const some_alloc&);
34 T *allocate(size_t);
35 };
36
37 template <class T>
38 struct some_alloc2
39 {
40 typedef T value_type;
41
some_alloc2some_alloc242 some_alloc2() {}
43 some_alloc2(const some_alloc2&);
44 T *allocate(size_t);
deallocatesome_alloc245 void deallocate(void*, unsigned) {}
46
47 typedef std::false_type propagate_on_container_move_assignment;
48 typedef std::true_type is_always_equal;
49 };
50
51 template <class T>
52 struct some_alloc3
53 {
54 typedef T value_type;
55
some_alloc3some_alloc356 some_alloc3() {}
57 some_alloc3(const some_alloc3&);
58 T *allocate(size_t);
deallocatesome_alloc359 void deallocate(void*, unsigned) {}
60
61 typedef std::false_type propagate_on_container_move_assignment;
62 typedef std::false_type is_always_equal;
63 };
64
test()65 TEST_CONSTEXPR_CXX20 bool test() {
66 {
67 typedef std::string C;
68 static_assert(std::is_nothrow_move_assignable<C>::value, "");
69 }
70 {
71 typedef std::basic_string<char, std::char_traits<char>, test_allocator<char>> C;
72 static_assert(!std::is_nothrow_move_assignable<C>::value, "");
73 }
74 {
75 typedef std::basic_string<char, std::char_traits<char>, some_alloc<char>> C;
76 #if TEST_STD_VER > 14
77 // if the allocators are always equal, then the move assignment can be noexcept
78 static_assert( std::is_nothrow_move_assignable<C>::value, "");
79 #else
80 static_assert(!std::is_nothrow_move_assignable<C>::value, "");
81 #endif
82 }
83 #if TEST_STD_VER > 14
84 {
85 // POCMA is false, always equal
86 typedef std::basic_string<char, std::char_traits<char>, some_alloc2<char>> C;
87 static_assert( std::is_nothrow_move_assignable<C>::value, "");
88 }
89 {
90 // POCMA is false, not always equal
91 typedef std::basic_string<char, std::char_traits<char>, some_alloc3<char>> C;
92 static_assert(!std::is_nothrow_move_assignable<C>::value, "");
93 }
94 #endif
95
96 return true;
97 }
98
main(int,char **)99 int main(int, char**)
100 {
101 test();
102 #if TEST_STD_VER > 17
103 static_assert(test());
104 #endif
105
106 return 0;
107 }
108