1 //===----------------------------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 // <optional>
11 
12 // template <class T>
13 // class optional
14 // {
15 // public:
16 //     typedef T value_type;
17 //     ...
18 
19 #include <experimental/optional>
20 #include <type_traits>
21 
22 #if _LIBCPP_STD_VER > 11
23 
24 using std::experimental::optional;
25 
26 template <class Opt, class T>
27 void
test()28 test()
29 {
30     static_assert(std::is_same<typename Opt::value_type, T>::value, "");
31 }
32 
33 #endif  // _LIBCPP_STD_VER > 11
34 
main()35 int main()
36 {
37 #if _LIBCPP_STD_VER > 11
38     test<optional<int>, int>();
39     test<optional<const int>, const int>();
40     test<optional<double>, double>();
41     test<optional<const double>, const double>();
42 #endif  // _LIBCPP_STD_VER > 11
43 }
44