1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 // UNSUPPORTED: c++03, c++11, c++14
10 // <optional>
11 
12 // constexpr const T& optional<T>::value() const &;
13 
14 #include <optional>
15 #include <type_traits>
16 #include <cassert>
17 
18 using std::optional;
19 
20 struct X
21 {
testX22     constexpr int test() const {return 3;}
testX23     int test() {return 4;}
24 };
25 
main(int,char **)26 int main(int, char**)
27 {
28     {
29         constexpr optional<X> opt;
30         static_assert(opt.value().test() == 3, "");
31     }
32 
33   return 0;
34 }
35