1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
4 // The LLVM Compiler Infrastructure
5 //
6 // This file is dual licensed under the MIT and the University of Illinois Open
7 // Source Licenses. See LICENSE.TXT for details.
8 //
9 //===----------------------------------------------------------------------===//
10
11 // UNSUPPORTED: c++98, c++03, c++11, c++14
12
13 // <variant>
14
15 // template <class ...Types> class variant;
16
17 // constexpr variant() noexcept(see below);
18
19 #include <cassert>
20 #include <type_traits>
21 #include <variant>
22
23 #include "test_macros.h"
24 #include "variant_test_helpers.hpp"
25
26 struct NonDefaultConstructible {
NonDefaultConstructibleNonDefaultConstructible27 NonDefaultConstructible(int) {}
28 };
29
30 struct NotNoexcept {
NotNoexceptNotNoexcept31 NotNoexcept() noexcept(false) {}
32 };
33
34 #ifndef TEST_HAS_NO_EXCEPTIONS
35 struct DefaultCtorThrows {
DefaultCtorThrowsDefaultCtorThrows36 DefaultCtorThrows() { throw 42; }
37 };
38 #endif
39
test_default_ctor_sfinae()40 void test_default_ctor_sfinae() {
41 {
42 using V = std::variant<std::monostate, int>;
43 static_assert(std::is_default_constructible<V>::value, "");
44 }
45 {
46 using V = std::variant<NonDefaultConstructible, int>;
47 static_assert(!std::is_default_constructible<V>::value, "");
48 }
49 #if !defined(TEST_VARIANT_HAS_NO_REFERENCES)
50 {
51 using V = std::variant<int &, int>;
52 static_assert(!std::is_default_constructible<V>::value, "");
53 }
54 #endif
55 }
56
test_default_ctor_noexcept()57 void test_default_ctor_noexcept() {
58 {
59 using V = std::variant<int>;
60 static_assert(std::is_nothrow_default_constructible<V>::value, "");
61 }
62 {
63 using V = std::variant<NotNoexcept>;
64 static_assert(!std::is_nothrow_default_constructible<V>::value, "");
65 }
66 }
67
test_default_ctor_throws()68 void test_default_ctor_throws() {
69 #ifndef TEST_HAS_NO_EXCEPTIONS
70 using V = std::variant<DefaultCtorThrows, int>;
71 try {
72 V v;
73 assert(false);
74 } catch (const int &ex) {
75 assert(ex == 42);
76 } catch (...) {
77 assert(false);
78 }
79 #endif
80 }
81
test_default_ctor_basic()82 void test_default_ctor_basic() {
83 {
84 std::variant<int> v;
85 assert(v.index() == 0);
86 assert(std::get<0>(v) == 0);
87 }
88 {
89 std::variant<int, long> v;
90 assert(v.index() == 0);
91 assert(std::get<0>(v) == 0);
92 }
93 {
94 using V = std::variant<int, long>;
95 constexpr V v;
96 static_assert(v.index() == 0, "");
97 static_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
main()107 int main() {
108 test_default_ctor_basic();
109 test_default_ctor_sfinae();
110 test_default_ctor_noexcept();
111 test_default_ctor_throws();
112 }
113