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
10
11 // Throwing bad_variant_access is supported starting in macosx10.13
12 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12}} && !no-exceptions
13
14 // <variant>
15
16 // template <class ...Types> class variant;
17
18 // constexpr variant() noexcept(see below);
19
20 #include <cassert>
21 #include <type_traits>
22 #include <variant>
23
24 #include "test_macros.h"
25 #include "variant_test_helpers.h"
26
27 struct NonDefaultConstructible {
NonDefaultConstructibleNonDefaultConstructible28 constexpr NonDefaultConstructible(int) {}
29 };
30
31 struct NotNoexcept {
NotNoexceptNotNoexcept32 NotNoexcept() noexcept(false) {}
33 };
34
35 #ifndef TEST_HAS_NO_EXCEPTIONS
36 struct DefaultCtorThrows {
DefaultCtorThrowsDefaultCtorThrows37 DefaultCtorThrows() { throw 42; }
38 };
39 #endif
40
test_default_ctor_sfinae()41 void test_default_ctor_sfinae() {
42 {
43 using V = std::variant<std::monostate, int>;
44 static_assert(std::is_default_constructible<V>::value, "");
45 }
46 {
47 using V = std::variant<NonDefaultConstructible, int>;
48 static_assert(!std::is_default_constructible<V>::value, "");
49 }
50 #if !defined(TEST_VARIANT_HAS_NO_REFERENCES)
51 {
52 using V = std::variant<int &, int>;
53 static_assert(!std::is_default_constructible<V>::value, "");
54 }
55 #endif
56 }
57
test_default_ctor_noexcept()58 void test_default_ctor_noexcept() {
59 {
60 using V = std::variant<int>;
61 static_assert(std::is_nothrow_default_constructible<V>::value, "");
62 }
63 {
64 using V = std::variant<NotNoexcept>;
65 static_assert(!std::is_nothrow_default_constructible<V>::value, "");
66 }
67 }
68
test_default_ctor_throws()69 void test_default_ctor_throws() {
70 #ifndef TEST_HAS_NO_EXCEPTIONS
71 using V = std::variant<DefaultCtorThrows, int>;
72 try {
73 V v;
74 assert(false);
75 } catch (const int &ex) {
76 assert(ex == 42);
77 } catch (...) {
78 assert(false);
79 }
80 #endif
81 }
82
test_default_ctor_basic()83 void test_default_ctor_basic() {
84 {
85 std::variant<int> v;
86 assert(v.index() == 0);
87 assert(std::get<0>(v) == 0);
88 }
89 {
90 std::variant<int, long> v;
91 assert(v.index() == 0);
92 assert(std::get<0>(v) == 0);
93 }
94 {
95 std::variant<int, NonDefaultConstructible> v;
96 assert(v.index() == 0);
97 assert(std::get<0>(v) == 0);
98 }
99 {
100 using V = std::variant<int, long>;
101 constexpr V v;
102 static_assert(v.index() == 0, "");
103 static_assert(std::get<0>(v) == 0, "");
104 }
105 {
106 using V = std::variant<int, long>;
107 constexpr V v;
108 static_assert(v.index() == 0, "");
109 static_assert(std::get<0>(v) == 0, "");
110 }
111 {
112 using V = std::variant<int, NonDefaultConstructible>;
113 constexpr V v;
114 static_assert(v.index() == 0, "");
115 static_assert(std::get<0>(v) == 0, "");
116 }
117 }
118
main(int,char **)119 int main(int, char**) {
120 test_default_ctor_basic();
121 test_default_ctor_sfinae();
122 test_default_ctor_noexcept();
123 test_default_ctor_throws();
124
125 return 0;
126 }
127