[committed] libstdc++: Specialize std::pointer_traits<__normal_iterator<I, C>>

[Jonathan Wakely]

On Sat, 2 Oct 2021 at 18:27, François Dumont wrote:
>
> I would like to propose this alternative approach.
>
> In this patch I make __normal_iterator and random iterator
> _Safe_iterator compatible for pointer_traits primary template.
>
> Regarding pointer_traits I wonder if it shouldn't check for the
> to_pointer method availability and use per default: return {
> std::addressof(__e) }; otherwise. This way we wouldn't have to provide a
> pointer_to method on __normal_iterator.

But I would rather not have these members present in vector::iterator
and string::iterator, in case users accidentally start to rely on them
being present.

Another option would be to overload std::__to_address so it knows how
to get the address from __normal_iterator and _Safe_iterator.