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++98, 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 int main(int, char**) 18 { 19 using std::optional; 20 using std::nullopt_t; 21 using std::nullopt; 22 23 { 24 typedef int T; 25 typedef optional<T> O; 26 27 constexpr O o1; // disengaged 28 constexpr O o2{1}; // engaged 29 30 static_assert ( (nullopt == o1), "" ); 31 static_assert ( !(nullopt == o2), "" ); 32 static_assert ( (o1 == nullopt), "" ); 33 static_assert ( !(o2 == nullopt), "" ); 34 35 static_assert (noexcept(nullopt == o1), ""); 36 static_assert (noexcept(o1 == nullopt), ""); 37 } 38 39 return 0; 40 } 41