Proposed resolution:

This wording is relative to N4981.

1. Modify [range.enumerate.iterator] as indicated:

   namespace std::ranges {
     template<view V>
       requires range-with-movable-references<V>
     template<bool Const>
     class enumerate_view<V>::iterator {
       using Base = maybe-const<Const, V>;                         // exposition only
   
     public:
       using iterator_category = input_iterator_tag;      // present only if Base
                                                          // models forward_range
       using iterator_concept = see below;
       […]
     };
   }
   

2. Modify [range.cartesian.iterator] as indicated:

   namespace std::ranges {
     template<input_range First, forward_range... Vs>
       requires (view<First> && ... && view<Vs>)
     template<bool Const>
     class cartesian_product_view<First, Vs...>::iterator {
     public:
       using iterator_category = input_iterator_tag;      // present only if maybe-const<Const, First>
                                                          // models forward_range
       using iterator_concept  = see below;
       […]
     };
   }
   

These two iterators do not support *r++ for non-forward iterators, so we should not provide iterator_category as they are not C++17 iterators.