Proposed resolution:

This wording is relative to N4910.

1. Modify [reverse.iter.elem] as indicated:

   constexpr pointer operator->() const
     requires (is_pointer_v<Iterator> ||
               requires(const Iterator i) { { i.operator->() } -> convertible_to<pointer>; });
   

   -2- Effects:

   1. (2.1) — If Iterator is a pointer type, equivalent to: return prev(current);

   2. (2.2) — Otherwise, equivalent to: return prev(current).operator->();

For non-pointer types, reverse_iterator::operator-> only requires the expression i.operator->() to be well-formed.

Since the return type of this function is explicitly specified as pointer, this will cause a hard error in the function body when the return type of i.operator->() cannot be converted to pointer.

We should add a return type constraint for this.