1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
|
// Copyright (C) 2019-2022 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
// { dg-options "-std=gnu++2a" }
// { dg-do run { target c++2a } }
#include <variant>
#include <testsuite_hooks.h>
void
test01()
{
struct Visitor
{
int operator()(int, void*) const { return 0; }
int operator()(char& c, void* p) const { return &c == p; }
int operator()(int i, const char* s) const { return s[i] == '\0'; }
int operator()(char c, const char* s) const { return c == *s; }
};
std::variant<int, char> v1{'c'};
std::variant<void*, const char*> v2{"chars"};
auto res = std::visit<bool>(Visitor{}, v1, v2);
static_assert(std::is_same_v<decltype(res), bool>);
VERIFY( res == true );
static_assert(std::is_void_v<decltype(std::visit<void>(Visitor{}, v1, v2))>);
}
void test02()
{
struct Visitor
{
int operator()(double) {return 42;}
double operator()(int) {return 0.02;}
};
std::variant<int, double> v;
std::visit<int>(Visitor(), v);
std::visit<const void>(Visitor(), v);
}
void test03()
{
// PR libstdc++/106589 - visit<void> rejects lambdas that do not return void
auto visitor = []{ return 0; };
std::visit<void>(visitor);
std::visit<void>(static_cast<int(*)()>(visitor));
}
int
main()
{
test01();
test02();
test03();
}
|
