37 struct OptionalStorage {  struct
40   constexpr OptionalStorage() : empty_('\0') {}  in OptionalStorage()  function
42   constexpr explicit OptionalStorage(const T& value)  in OptionalStorage()  argument
46   explicit OptionalStorage(T&& value)  in OptionalStorage()  function
51   explicit OptionalStorage(in_place_t, Args&&... args)  in OptionalStorage()  argument
56   ~OptionalStorage() {  in ~OptionalStorage()  argument
72 struct OptionalStorage<T, true> {  argument
75   constexpr OptionalStorage() : empty_('\0') {}
77   constexpr explicit OptionalStorage(const T& value)
81   explicit OptionalStorage(T&& value)
86   explicit OptionalStorage(in_place_t, Args&&... args)
92   ~OptionalStorage() = default;
332   internal::OptionalStorage<T> storage_;