Subject: bug#37337: [PATCH] Fix bug in `TeX-fold-hide-item' when acting on evaporated overlays

From: Arash Esbati <[email-masked]>
Date: Thu, 24 Oct 2019 21:50:19 +0200

Hi Florent,

Florent Rougon <[email-masked]> writes:

> * tex-fold.el (TeX-fold-hide-item): wrap the end of the function in
> (unless (equal ov-start ov-end) ...). What is done in this part isn't
> useful with evaporated overlays and used to cause bugs because
> `overlay-start' and `overlay-end' return nil for such overlays, and
> functions such as `TeX-fold-overfull-p` try to move point to the
> overlay-end. Fixes bug#37337.

Many thanks for tracking this down.  I can confirm the bug you describe,
and have a question reg. your patch: If it's only about checking if
`overlay-start' and `overlay-end' are non-nil, wouldn't it be easier to
do:

    (when (and ov-start ov-end) ...)

instead of

    (unless (equal ov-start ov-end) ...)

?
Best, Arash