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// type_traits
10
11// is_assignable
12
13#include <type_traits>
14#include "test_macros.h"
15
16struct A
17{
18};
19
20struct B
21{
22 void operator=(A);
23};
24
25template <class T, class U>
26void test_is_assignable()
27{
28 static_assert(( std::is_assignable<T, U>::value), "");
29#if TEST_STD_VER > 14
30 static_assert( std::is_assignable_v<T, U>, "");
31#endif
32}
33
34template <class T, class U>
35void test_is_not_assignable()
36{
37 static_assert((!std::is_assignable<T, U>::value), "");
38#if TEST_STD_VER > 14
39 static_assert( !std::is_assignable_v<T, U>, "");
40#endif
41}
42
43struct D;
44
45#if TEST_STD_VER >= 11
46struct C
47{
48 template <class U>
49 D operator,(U&&);
50};
51
52struct E
53{
54 C operator=(int);
55};
56#endif
57
58template <typename T>
59struct X { T t; };
60
61int main(int, char**)
62{
63 test_is_assignable<int&, int&> ();
64 test_is_assignable<int&, int> ();
65 test_is_assignable<int&, double> ();
66 test_is_assignable<B, A> ();
67 test_is_assignable<void*&, void*> ();
68
69#if TEST_STD_VER >= 11
70 test_is_assignable<E, int> ();
71
72 test_is_not_assignable<int, int&> ();
73 test_is_not_assignable<int, int> ();
74#endif
75 test_is_not_assignable<A, B> ();
76 test_is_not_assignable<void, const void> ();
77 test_is_not_assignable<const void, const void> ();
78 test_is_not_assignable<int(), int> ();
79
80// pointer to incomplete template type
81 test_is_assignable<X<D>*&, X<D>*> ();
82
83 return 0;
84}
85

source code of libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_assignable.pass.cpp