Proposed resolution:

This wording is relative to N4849.

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

   namespace std::ranges {
     template<class Val, class CharT, class Traits>
     class basic_istream_view<Val, CharT, Traits>::iterator { // exposition only
     public:
       using iterator_categoryiterator_concept = input_iterator_tag;
       using difference_type = ptrdiff_t;
       using value_type = Val;
   
       iterator() = default;
       […]
     };
   }
   

[ 2020-02 Status to Immediate on Thursday night in Prague. ]

The ranges::basic_istream_view::iterator is a move-only type, and as such it does not meets the Cpp17 iterator requirements, yet it does provides iterator_category (intended to be used for Cpp17 iterators). We should provide iterator_concept instead.