bug#35273: "Marker does not point anywhere" when reading next article

[Eli Zaretskii]

> From: Noam Postavsky <npostavs@gmail.com>
> Cc: contovob@tcd.ie,  35273@debbugs.gnu.org,  leah@vuxu.org
> Date: Sat, 20 Apr 2019 08:05:30 -0400
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> From: Noam Postavsky <npostavs@gmail.com>
> >> Date: Tue, 16 Apr 2019 09:56:36 -0400
> >> Cc: "Basil L. Contovounesios" <contovob@tcd.ie>, 35273@debbugs.gnu.org
> >> 
> >> Oh right, OVERLAY_POSITION calls marker_position.  I think the patch
> >> below should paper over the problem, but I'm not sure if it's the right
> >> thing.
> >
> > I think it would be better to try to understand how we got such an
> > overlay.  Was it deleted, per chance?
> 
> I entirely agree with this, but how to check for that?

But a breakpoint in delete-overlay?