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 // <iterator>
12
13 // move_sentinel
14
15 // template<class S2>
16 // requires assignable_from<S&, const S2&>
17 // constexpr move_sentinel& operator=(const move_sentinel<S2>& s);
18
19 #include <cassert>
20 #include <concepts>
21 #include <iterator>
22 #include <type_traits>
23
24 struct NonAssignable {
25 NonAssignable& operator=(int i);
26 };
27 static_assert(std::semiregular<NonAssignable>);
28 static_assert(std::is_assignable_v<NonAssignable, int>);
29 static_assert(!std::assignable_from<NonAssignable, int>);
30
test()31 constexpr bool test()
32 {
33 // Assigning from an lvalue.
34 {
35 std::move_sentinel<int> m(42);
36 std::move_sentinel<long> m2;
37 m2 = m;
38 assert(m2.base() == 42L);
39 }
40
41 // Assigning from an rvalue.
42 {
43 std::move_sentinel<long> m2;
44 m2 = std::move_sentinel<int>(43);
45 assert(m2.base() == 43L);
46 }
47
48 // SFINAE checks.
49 {
50 static_assert( std::is_assignable_v<std::move_sentinel<int>, std::move_sentinel<long>>);
51 static_assert(!std::is_assignable_v<std::move_sentinel<int*>, std::move_sentinel<const int*>>);
52 static_assert( std::is_assignable_v<std::move_sentinel<const int*>, std::move_sentinel<int*>>);
53 static_assert(!std::is_assignable_v<std::move_sentinel<NonAssignable>, std::move_sentinel<int>>);
54 }
55 return true;
56 }
57
main(int,char **)58 int main(int, char**)
59 {
60 test();
61 static_assert(test());
62
63 return 0;
64 }
65