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// optional<T>& operator=(nullopt_t) noexcept; 13 14#include <experimental/optional> 15#include <type_traits> 16#include <cassert> 17 18#if _LIBCPP_STD_VER > 11 19 20using std::experimental::optional; 21using std::experimental::nullopt_t; 22using std::experimental::nullopt; 23 24struct X 25{ 26 static bool dtor_called; 27 ~X() {dtor_called = true;} 28}; 29 30bool X::dtor_called = false; 31 32#endif // _LIBCPP_STD_VER > 11 33 34int main() 35{ 36#if _LIBCPP_STD_VER > 11 37 { 38 optional<int> opt; 39 static_assert(noexcept(opt = nullopt) == true, ""); 40 opt = nullopt; 41 assert(static_cast<bool>(opt) == false); 42 } 43 { 44 optional<int> opt(3); 45 opt = nullopt; 46 assert(static_cast<bool>(opt) == false); 47 } 48 { 49 optional<X> opt; 50 static_assert(noexcept(opt = nullopt) == true, ""); 51 assert(X::dtor_called == false); 52 opt = nullopt; 53 assert(X::dtor_called == false); 54 assert(static_cast<bool>(opt) == false); 55 } 56 { 57 X x; 58 { 59 optional<X> opt(x); 60 assert(X::dtor_called == false); 61 opt = nullopt; 62 assert(X::dtor_called == true); 63 assert(static_cast<bool>(opt) == false); 64 } 65 } 66#endif // _LIBCPP_STD_VER > 11 67} 68