1
2// Copyright 2017 Peter Dimov.
3//
4// Distributed under the Boost Software License, Version 1.0.
5//
6// See accompanying file LICENSE_1_0.txt or copy at
7// http://www.boost.org/LICENSE_1_0.txt
8
9#include <boost/variant2/variant.hpp>
10#include <boost/core/lightweight_test.hpp>
11#include <boost/core/lightweight_test_trait.hpp>
12#include <type_traits>
13#include <utility>
14#include <string>
15
16using namespace boost::variant2;
17
18struct X
19{
20 X();
21};
22
23struct Y
24{
25 Y() = delete;
26};
27
28int main()
29{
30 {
31 variant<int> v;
32
33 BOOST_TEST_EQ( v.index(), 0 );
34 BOOST_TEST_EQ( get<0>(v), 0 );
35 }
36
37 {
38 variant<int const> v;
39
40 BOOST_TEST_EQ( v.index(), 0 );
41 BOOST_TEST_EQ( get<0>(v), 0 );
42 }
43
44 {
45 variant<int, float, std::string> v;
46
47 BOOST_TEST_EQ( v.index(), 0 );
48 BOOST_TEST_EQ( get<0>(v), 0 );
49 }
50
51 {
52 variant<int, int, std::string> v;
53
54 BOOST_TEST_EQ( v.index(), 0 );
55 BOOST_TEST_EQ( get<0>(v), 0 );
56 }
57
58 {
59 variant<std::string> v;
60
61 BOOST_TEST_EQ( v.index(), 0 );
62 BOOST_TEST_EQ( get<0>(v), std::string() );
63 }
64
65 {
66 variant<std::string const> v;
67
68 BOOST_TEST_EQ( v.index(), 0 );
69 BOOST_TEST_EQ( get<0>(v), std::string() );
70 }
71
72 {
73 variant<std::string, int, float> v;
74
75 BOOST_TEST_EQ( v.index(), 0 );
76 BOOST_TEST_EQ( get<0>(v), std::string() );
77 }
78
79 {
80 variant<std::string, std::string, float> v;
81
82 BOOST_TEST_EQ( v.index(), 0 );
83 BOOST_TEST_EQ( get<0>(v), std::string() );
84 }
85
86 {
87 BOOST_TEST_TRAIT_TRUE((std::is_nothrow_default_constructible<variant<int>>));
88 BOOST_TEST_TRAIT_TRUE((std::is_nothrow_default_constructible<variant<int const>>));
89 BOOST_TEST_TRAIT_TRUE((std::is_nothrow_default_constructible<variant<int, X>>));
90 BOOST_TEST_TRAIT_TRUE((std::is_nothrow_default_constructible<variant<int, float, X>>));
91 BOOST_TEST_TRAIT_TRUE((std::is_nothrow_default_constructible<variant<int, int, X>>));
92 BOOST_TEST_TRAIT_TRUE((std::is_nothrow_default_constructible<variant<int, X, X>>));
93
94 BOOST_TEST_TRAIT_FALSE((std::is_nothrow_default_constructible<variant<X>>));
95 BOOST_TEST_TRAIT_FALSE((std::is_nothrow_default_constructible<variant<X, int>>));
96 BOOST_TEST_TRAIT_FALSE((std::is_nothrow_default_constructible<variant<X, int, float>>));
97
98 BOOST_TEST_TRAIT_TRUE((std::is_default_constructible<variant<int, Y>>));
99 BOOST_TEST_TRAIT_FALSE((std::is_default_constructible<variant<Y, int>>));
100 }
101
102 return boost::report_errors();
103}
104

source code of boost/libs/variant2/test/variant_default_construct.cpp