For the sake of exposition, [support] through [exec]
and [depr] do not describe copy/move constructors, assignment
operators, or (non-virtual) destructors with the same apparent
semantics as those that can be generated
by default ([class.copy.ctor], [class.copy.assign], [class.dtor]).
It is unspecified whether
the implementation provides explicit definitions for such member function
signatures, or for virtual destructors that can be generated by default.