20 General utilities library [utilities]

20.10 Memory [memory]

20.10.3 Pointer traits [pointer.traits]

20.10.3.2 Member types [pointer.traits.types]

using element_type = see below;
Type: Ptr​::​element_­type if the qualified-id Ptr​::​element_­type is valid and denotes a type ([temp.deduct]); otherwise, T if Ptr is a class template instantiation of the form SomePointer<T, Args>, where Args is zero or more type arguments; otherwise, the specialization is ill-formed.
using difference_type = see below;
Type: Ptr​::​difference_­type if the qualified-id Ptr​::​difference_­type is valid and denotes a type ([temp.deduct]); otherwise, ptrdiff_­t.
template<class U> using rebind = see below;
Alias template: Ptr​::​rebind<U> if the qualified-id Ptr​::​rebind<U> is valid and denotes a type ([temp.deduct]); otherwise, SomePointer<U, Args> if Ptr is a class template instantiation of the form SomePointer<T, Args>, where Args is zero or more type arguments; otherwise, the instantiation of rebind is ill-formed.