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
11 using namespace boost::variant2;
12
13 struct X
14 {
15 int v;
16 X() = default;
XX17 constexpr explicit X( int v ): v( v ) {}
operator intX18 constexpr operator int() const { return v; }
19 };
20
21 struct Y
22 {
23 int v;
YY24 constexpr Y(): v() {}
YY25 constexpr explicit Y( int v ): v( v ) {}
operator intY26 constexpr operator int() const { return v; }
27 };
28
29 #define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
30
test(A const & a)31 template<class V, std::size_t I, class A> constexpr A test( A const& a )
32 {
33 V v;
34
35 v.template emplace<I>( a );
36
37 return get<I>(v);
38 }
39
main()40 int main()
41 {
42 {
43 constexpr auto w = test<variant<int>, 0>( 1 );
44 STATIC_ASSERT( w == 1 );
45 }
46
47 {
48 constexpr auto w = test<variant<X>, 0>( 1 );
49 STATIC_ASSERT( w == 1 );
50 }
51
52 #if defined( BOOST_LIBSTDCXX_VERSION ) && BOOST_LIBSTDCXX_VERSION < 50000
53 #else
54
55 {
56 constexpr auto w = test<variant<Y>, 0>( 1 );
57 STATIC_ASSERT( w == 1 );
58 }
59
60 #endif
61
62 {
63 constexpr auto w = test<variant<int, float>, 0>( 1 );
64 STATIC_ASSERT( w == 1 );
65 }
66
67 {
68 constexpr auto w = test<variant<int, float>, 1>( 3.0f );
69 STATIC_ASSERT( w == 3.0f );
70 }
71
72 {
73 constexpr auto w = test<variant<int, int, float, float, X, X>, 0>( 1 );
74 STATIC_ASSERT( w == 1 );
75 }
76
77 {
78 constexpr auto w = test<variant<int, int, float, float, X, X>, 1>( 1 );
79 STATIC_ASSERT( w == 1 );
80 }
81
82 {
83 constexpr auto w = test<variant<int, int, float, float, X, X>, 2>( 2.0f );
84 STATIC_ASSERT( w == 2.0f );
85 }
86
87 {
88 constexpr auto w = test<variant<int, int, float, float, X, X>, 3>( 3.0f );
89 STATIC_ASSERT( w == 3.0f );
90 }
91
92 {
93 constexpr auto w = test<variant<int, int, float, float, X, X>, 4>( 4 );
94 STATIC_ASSERT( w == 4 );
95 }
96
97 {
98 constexpr auto w = test<variant<int, int, float, float, X, X>, 5>( 5 );
99 STATIC_ASSERT( w == 5 );
100 }
101
102 #if defined( BOOST_LIBSTDCXX_VERSION ) && BOOST_LIBSTDCXX_VERSION < 50000
103 #else
104
105 {
106 constexpr auto w = test<variant<int, int, float, float, Y, Y>, 0>( 1 );
107 STATIC_ASSERT( w == 1 );
108 }
109
110 {
111 constexpr auto w = test<variant<int, int, float, float, Y, Y>, 1>( 1 );
112 STATIC_ASSERT( w == 1 );
113 }
114
115 {
116 constexpr auto w = test<variant<int, int, float, float, Y, Y>, 2>( 2.0f );
117 STATIC_ASSERT( w == 2.0f );
118 }
119
120 {
121 constexpr auto w = test<variant<int, int, float, float, Y, Y>, 3>( 3.0f );
122 STATIC_ASSERT( w == 3.0f );
123 }
124
125 {
126 constexpr auto w = test<variant<int, int, float, float, Y, Y>, 4>( 4 );
127 STATIC_ASSERT( w == 4 );
128 }
129
130 {
131 constexpr auto w = test<variant<int, int, float, float, Y, Y>, 5>( 5 );
132 STATIC_ASSERT( w == 5 );
133 }
134
135 #endif
136 }
137