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 // template <class T> constexpr bool operator<(const optional<T>& x, nullopt_t) noexcept;
13 // template <class T> constexpr bool operator<(nullopt_t, const optional<T>& x) noexcept;
14 
15 #include <optional>
16 
17 #include "test_macros.h"
18 
19 int main(int, char**)
20 {
21     using std::optional;
22     using std::nullopt_t;
23     using std::nullopt;
24 
25     {
26     typedef int T;
27     typedef optional<T> O;
28 
29     constexpr O o1;     // disengaged
30     constexpr O o2{1};  // engaged
31 
32     static_assert ( !(nullopt < o1), "" );
33     static_assert (  (nullopt < o2), "" );
34     static_assert ( !(o1 < nullopt), "" );
35     static_assert ( !(o2 < nullopt), "" );
36 
37     static_assert (noexcept(nullopt < o1), "");
38     static_assert (noexcept(o1 < nullopt), "");
39     }
40 
41   return 0;
42 }
43