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 // constexpr const T& optional<T>::value() const;
13 
14 #include <experimental/optional>
15 #include <type_traits>
16 #include <cassert>
17 
18 #if _LIBCPP_STD_VER > 11
19 
20 using std::experimental::optional;
21 
22 struct X
23 {
testX24     constexpr int test() const {return 3;}
testX25     int test() {return 4;}
26 };
27 
28 #endif  // _LIBCPP_STD_VER > 11
29 
main()30 int main()
31 {
32 #if _LIBCPP_STD_VER > 11
33     {
34         constexpr optional<X> opt;
35         static_assert(opt.value().test() == 3, "");
36     }
37 #else
38 #error
39 #endif  // _LIBCPP_STD_VER > 11
40 }
41