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 // The following compilers don't allow constexpr variables of non-literal type.
14 // XFAIL: gcc-5, gcc-6
15 // XFAIL: clang-3.5, clang-3.6, clang-3.7, clang-3.8
16 // XFAIL: apple-clang-6, apple-clang-7, apple-clang-8
17 
18 // <variant>
19 
20 // template <class ...Types> class variant;
21 
22 // constexpr size_t index() const noexcept;
23 
24 #include <cassert>
25 #include <string>
26 #include <type_traits>
27 #include <variant>
28 
29 #include "archetypes.hpp"
30 #include "test_macros.h"
31 #include "variant_test_helpers.hpp"
32 
33 int main() {
34   {
35     using V = std::variant<int, ConstexprTestTypes::NoCtors>;
36     constexpr V v;
37     static_assert(v.index() == 0, "");
38   }
39   {
40     using V = std::variant<int, long>;
41     constexpr V v(std::in_place_index<1>);
42     static_assert(v.index() == 1, "");
43   }
44   {
45     using V = std::variant<int, std::string>;
46     V v("abc");
47     assert(v.index() == 1);
48     v = 42;
49     assert(v.index() == 0);
50   }
51 #ifndef TEST_HAS_NO_EXCEPTIONS
52   {
53     using V = std::variant<int, MakeEmptyT>;
54     V v;
55     assert(v.index() == 0);
56     makeEmpty(v);
57     assert(v.index() == std::variant_npos);
58   }
59 #endif
60 }
61