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 // UNSUPPORTED: c++98, c++03, c++11, c++14 11 // <optional> 12 13 // template <class T> constexpr bool operator==(const optional<T>& x, nullopt_t) noexcept; 14 // template <class T> constexpr bool operator==(nullopt_t, const optional<T>& x) noexcept; 15 16 #include <optional> 17 18 int main() 19 { 20 using std::optional; 21 using std::nullopt_t; 22 using std::nullopt; 23 24 { 25 typedef int T; 26 typedef optional<T> O; 27 28 constexpr O o1; // disengaged 29 constexpr O o2{1}; // engaged 30 31 static_assert ( (nullopt == o1), "" ); 32 static_assert ( !(nullopt == o2), "" ); 33 static_assert ( (o1 == nullopt), "" ); 34 static_assert ( !(o2 == nullopt), "" ); 35 36 static_assert (noexcept(nullopt == o1), ""); 37 static_assert (noexcept(o1 == nullopt), ""); 38 } 39 } 40
