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 // struct nullopt_t{see below};
13 // constexpr nullopt_t nullopt(unspecified);
14 
15 #include <experimental/optional>
16 #include <type_traits>
17 
18 #if _LIBCPP_STD_VER > 11
19 
20 using std::experimental::optional;
21 using std::experimental::nullopt_t;
22 using std::experimental::nullopt;
23 
24 constexpr
25 int
test(const nullopt_t &)26 test(const nullopt_t&)
27 {
28     return 3;
29 }
30 
31 #endif
32 
main()33 int main()
34 {
35 #if _LIBCPP_STD_VER > 11
36     static_assert((std::is_class<nullopt_t>::value), "");
37     static_assert((std::is_empty<nullopt_t>::value), "");
38     static_assert((std::is_literal_type<nullopt_t>::value), "");
39     static_assert((!std::is_default_constructible<nullopt_t>::value), "");
40 
41     static_assert(test(nullopt) == 3, "");
42 #endif
43 }
44