145 class Optional;  variable
165     friend class Optional;  variable
189     constexpr Optional() {}  in Optional()  function
190     constexpr Optional(NulloptT) {}  in Optional()  function
192     Optional(const Optional& other) : base_flag(other.constructed()) {  in Optional()  function
197     Optional(Optional&& other) : base_flag(other.constructed()) {  in Optional()  function
207     Optional(const Optional<U>& other) : base_flag(other.constructed()) {  in Optional()  function
217     Optional(Optional<U>&& other) : base_flag(other.constructed()) {  in Optional()  function
224     Optional(const T& value) : base_flag(true) { new (&get()) T(value); }  in Optional()  function
226     Optional(T&& value) : base_flag(true) { new (&get()) T(std::move(value)); }  in Optional()  function
230     Optional(InplaceT, Args&&... args) : base_flag(true) {  in Optional()  function
238     Optional(InplaceT, std::initializer_list<U> il) : base_flag(true) {  in Optional()  function