Referring to the view in iterators  is not uncommon - for example http://eel.is/c++draft/ranges#range.istream.iterator

Per [range.range]p5, iterators produced from a borrowed range type (which utf_view is) are valid independently of the lifetime of the range object that produced them. Thus, such iterators cannot query their associated range object (but they might be able to query the underlying range object if known and if it is not a borrowed range).

Tom.

For the bidirectional-at-most, there is a blurb http://eel.is/c++draft/ranges#range.iota.iterator-1  - I think Jonathan was wanting to factorise that out somewhere but right now you basically have to copy the blob