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
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
|
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14
// Throwing bad_variant_access is supported starting in macosx10.13
// XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12}} && !no-exceptions
// <variant>
// template <class ...Types> class variant;
// constexpr variant() noexcept(see below);
#include <cassert>
#include <type_traits>
#include <variant>
#include "test_macros.h"
#include "variant_test_helpers.h"
struct NonDefaultConstructible {
constexpr NonDefaultConstructible(int) {}
};
struct NotNoexcept {
NotNoexcept() noexcept(false) {}
};
#ifndef TEST_HAS_NO_EXCEPTIONS
struct DefaultCtorThrows {
DefaultCtorThrows() { throw 42; }
};
#endif
void test_default_ctor_sfinae() {
{
using V = std::variant<std::monostate, int>;
static_assert(std::is_default_constructible<V>::value, "");
}
{
using V = std::variant<NonDefaultConstructible, int>;
static_assert(!std::is_default_constructible<V>::value, "");
}
#if !defined(TEST_VARIANT_HAS_NO_REFERENCES)
{
using V = std::variant<int &, int>;
static_assert(!std::is_default_constructible<V>::value, "");
}
#endif
}
void test_default_ctor_noexcept() {
{
using V = std::variant<int>;
static_assert(std::is_nothrow_default_constructible<V>::value, "");
}
{
using V = std::variant<NotNoexcept>;
static_assert(!std::is_nothrow_default_constructible<V>::value, "");
}
}
void test_default_ctor_throws() {
#ifndef TEST_HAS_NO_EXCEPTIONS
using V = std::variant<DefaultCtorThrows, int>;
try {
V v;
assert(false);
} catch (const int &ex) {
assert(ex == 42);
} catch (...) {
assert(false);
}
#endif
}
void test_default_ctor_basic() {
{
std::variant<int> v;
assert(v.index() == 0);
assert(std::get<0>(v) == 0);
}
{
std::variant<int, long> v;
assert(v.index() == 0);
assert(std::get<0>(v) == 0);
}
{
std::variant<int, NonDefaultConstructible> v;
assert(v.index() == 0);
assert(std::get<0>(v) == 0);
}
{
using V = std::variant<int, long>;
constexpr V v;
static_assert(v.index() == 0, "");
static_assert(std::get<0>(v) == 0, "");
}
{
using V = std::variant<int, long>;
constexpr V v;
static_assert(v.index() == 0, "");
static_assert(std::get<0>(v) == 0, "");
}
{
using V = std::variant<int, NonDefaultConstructible>;
constexpr V v;
static_assert(v.index() == 0, "");
static_assert(std::get<0>(v) == 0, "");
}
}
int main(int, char**) {
test_default_ctor_basic();
test_default_ctor_sfinae();
test_default_ctor_noexcept();
test_default_ctor_throws();
return 0;
}
|
