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 20 using std::experimental::optional; 21 using std::experimental::nullopt_t; 22 using std::experimental::nullopt; 23 24 struct X 25 { 26 static bool dtor_called; 27 ~X() {dtor_called = true;} 28 }; 29 30 bool X::dtor_called = false; 31 32 #endif // _LIBCPP_STD_VER > 11 33 34 int 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
