> So here is the complete implementation that was made possible
> thanks to the suggestions in
> https://lists.gnu.org/archive/html/emacs-devel/2022-06/msg01208.html
>
> For example, searching for the word "nongnu" in etc/ORG-NEWS
> when all outlines are collapsed with isearch-lazy-count=t
> will show such prompts:
>
> search-invisible = t      1/4 I-search:
> search-invisible = open   1/2 (invisible 2) I-search:
> search-invisible = nil    0/0 (invisible 4) I-search:
>
> where such numbers as "1/2" show the matches that can be visited by isearch,
> and "(invisible 2)" are the rest of matches unreachable by isearch.

Here are more fixes with tests: