bug#30800: 26.0.91; unknown crash on macos

[Eli Zaretskii]

> Date: Wed, 21 Mar 2018 19:00:12 +0200
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: 30800@debbugs.gnu.org
> 
> > > Which part of FRAME_NS_VIEW causes the crash?  There are 2
> > > dereferences there; which one is the culprit?
> > 
> > I believe it's the first:
> > 
> > (lldb) p represented_frame->output_data
> > error: Couldn't apply expression side effects : Couldn't dematerialize
> > a result variable: couldn't read its memory
> 
> Please also show the value of represented_frame itself.

And crystal ball says this has something to do with commit f7a853d.