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/mp11.hpp>
11#include <boost/core/lightweight_test.hpp>
12#include <boost/core/lightweight_test_trait.hpp>
13#include <type_traits>
14#include <cstddef>
15
16using namespace boost::variant2;
17using namespace boost::mp11;
18
19template<class I, class T> using var_alt_t = variant_alternative_t<I::value, T>;
20
21int main()
22{
23 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void>>, void>));
24 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void> const>, void const>));
25 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void> volatile>, void volatile>));
26 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void> const volatile>, void const volatile>));
27
28 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char>&>, char&>));
29 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char> const&>, char const&>));
30 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char>&&>, char&&>));
31 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char> const&&>, char const&&>));
32
33 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void, int>>, void>));
34 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void, int> const>, void const>));
35 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void, int> volatile>, void volatile>));
36 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void, int> const volatile>, void const volatile>));
37
38 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char, int>&>, char&>));
39 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char, int> const&>, char const&>));
40 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char, int>&&>, char&&>));
41 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char, int> const&&>, char const&&>));
42
43 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int>>, int>));
44 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int> const>, int const>));
45 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int> volatile>, int volatile>));
46 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int> const volatile>, int const volatile>));
47
48 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int>&>, int&>));
49 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int> const&>, int const&>));
50 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int>&&>, int&&>));
51 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int> const&&>, int const&&>));
52
53 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void, int, float>>, void>));
54 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void, int, float> const>, void const>));
55 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void, int, float> volatile>, void volatile>));
56 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<void, int, float> const volatile>, void const volatile>));
57
58 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char, int, float>&>, char&>));
59 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char, int, float> const&>, char const&>));
60 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char, int, float>&&>, char&&>));
61 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<0, variant<char, int, float> const&&>, char const&&>));
62
63 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int, float>>, int>));
64 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int, float> const>, int const>));
65 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int, float> volatile>, int volatile>));
66 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int, float> const volatile>, int const volatile>));
67
68 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int, float>&>, int&>));
69 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int, float> const&>, int const&>));
70 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int, float>&&>, int&&>));
71 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<1, variant<void, int, float> const&&>, int const&&>));
72
73 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<2, variant<void, int, float>>, float>));
74 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<2, variant<void, int, float> const>, float const>));
75 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<2, variant<void, int, float> volatile>, float volatile>));
76 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<2, variant<void, int, float> const volatile>, float const volatile>));
77
78 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<2, variant<void, int, float>&>, float&>));
79 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<2, variant<void, int, float> const&>, float const&>));
80 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<2, variant<void, int, float>&&>, float&&>));
81 BOOST_TEST_TRAIT_TRUE((std::is_same<variant_alternative_t<2, variant<void, int, float> const&&>, float const&&>));
82
83 variant_alternative<0, void>();
84 variant_alternative<0, void const>();
85 variant_alternative<0, void volatile>();
86 variant_alternative<0, void const volatile>();
87
88 variant_alternative<0, int&>();
89 variant_alternative<0, int const&>();
90 variant_alternative<0, int&&>();
91 variant_alternative<0, int const&&>();
92
93 variant_alternative<0, variant<>>();
94 variant_alternative<0, variant<> const>();
95 variant_alternative<0, variant<> volatile>();
96 variant_alternative<0, variant<> const volatile>();
97
98 variant_alternative<0, variant<>&>();
99 variant_alternative<0, variant<> const&>();
100 variant_alternative<0, variant<>&&>();
101 variant_alternative<0, variant<> const&&>();
102
103 variant_alternative<1, variant<int>>();
104 variant_alternative<1, variant<int> const>();
105 variant_alternative<1, variant<int> volatile>();
106 variant_alternative<1, variant<int> const volatile>();
107
108 variant_alternative<1, variant<int>&>();
109 variant_alternative<1, variant<int> const&>();
110 variant_alternative<1, variant<int>&&>();
111 variant_alternative<1, variant<int> const&&>();
112
113 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, void>));
114 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, void const>));
115 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, void volatile>));
116 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, void const volatile>));
117
118 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, int&>));
119 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, int const&>));
120 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, int&&>));
121 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, int const&&>));
122
123 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, variant<>>));
124 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, variant<> const>));
125 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, variant<> volatile>));
126 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, variant<> const volatile>));
127
128 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, variant<>&>));
129 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, variant<> const&>));
130 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, variant<>&&>));
131 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<0>, variant<> const&&>));
132
133 BOOST_TEST_TRAIT_TRUE((mp_valid<var_alt_t, mp_size_t<0>, variant<int>>));
134 BOOST_TEST_TRAIT_TRUE((mp_valid<var_alt_t, mp_size_t<0>, variant<int> const>));
135 BOOST_TEST_TRAIT_TRUE((mp_valid<var_alt_t, mp_size_t<0>, variant<int> volatile>));
136 BOOST_TEST_TRAIT_TRUE((mp_valid<var_alt_t, mp_size_t<0>, variant<int> const volatile>));
137
138 BOOST_TEST_TRAIT_TRUE((mp_valid<var_alt_t, mp_size_t<0>, variant<int>&>));
139 BOOST_TEST_TRAIT_TRUE((mp_valid<var_alt_t, mp_size_t<0>, variant<int> const&>));
140 BOOST_TEST_TRAIT_TRUE((mp_valid<var_alt_t, mp_size_t<0>, variant<int>&&>));
141 BOOST_TEST_TRAIT_TRUE((mp_valid<var_alt_t, mp_size_t<0>, variant<int> const&&>));
142
143 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<1>, variant<int>>));
144 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<1>, variant<int> const>));
145 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<1>, variant<int> volatile>));
146 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<1>, variant<int> const volatile>));
147
148 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<1>, variant<int>&>));
149 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<1>, variant<int> const&>));
150 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<1>, variant<int>&&>));
151 BOOST_TEST_TRAIT_FALSE((mp_valid<var_alt_t, mp_size_t<1>, variant<int> const&&>));
152
153 return boost::report_errors();
154}
155

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