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 11 // <optional> 12 13 // optional<T>& operator=(nullopt_t) noexcept; 14 15 #include <experimental/optional> 16 #include <type_traits> 17 #include <cassert> 18 19 using std::experimental::optional; 20 using std::experimental::nullopt_t; 21 using std::experimental::nullopt; 22 23 struct X 24 { 25 static bool dtor_called; ~XX26 ~X() {dtor_called = true;} 27 }; 28 29 bool X::dtor_called = false; 30 main()31int main() 32 { 33 { 34 optional<int> opt; 35 static_assert(noexcept(opt = nullopt) == true, ""); 36 opt = nullopt; 37 assert(static_cast<bool>(opt) == false); 38 } 39 { 40 optional<int> opt(3); 41 opt = nullopt; 42 assert(static_cast<bool>(opt) == false); 43 } 44 { 45 optional<X> opt; 46 static_assert(noexcept(opt = nullopt) == true, ""); 47 assert(X::dtor_called == false); 48 opt = nullopt; 49 assert(X::dtor_called == false); 50 assert(static_cast<bool>(opt) == false); 51 } 52 { 53 X x; 54 { 55 optional<X> opt(x); 56 assert(X::dtor_called == false); 57 opt = nullopt; 58 assert(X::dtor_called == true); 59 assert(static_cast<bool>(opt) == false); 60 } 61 } 62 } 63