148 class Optional;  variable
168     friend class Optional;  variable
192     constexpr Optional() {}  in Optional()  function
193     constexpr Optional(NulloptT) {}  in Optional()  function
195     Optional(const Optional& other) : base_flag(other.constructed()) {  in Optional()  function
200     Optional(Optional&& other) : base_flag(other.constructed()) {  in Optional()  function
210     Optional(const Optional<U>& other) : base_flag(other.constructed()) {  in Optional()  function
220     Optional(Optional<U>&& other) : base_flag(other.constructed()) {  in Optional()  function
227     Optional(const T& value) : base_flag(true) { new (&get()) T(value); }  in Optional()  function
229     Optional(T&& value) : base_flag(true) { new (&get()) T(std::move(value)); }  in Optional()  function
233     Optional(InplaceT, Args&&... args) : base_flag(true) {  in Optional()  function
241     Optional(InplaceT, std::initializer_list<U> il) : base_flag(true) {  in Optional()  function