bug#41321: 27.0.91; Emacs aborts due to invalid pseudovector objects

[Eli Zaretskii]

> From: Pip Cet <pipcet@gmail.com>
> Date: Fri, 22 May 2020 11:47:03 +0000
> Cc: Stefan Monnier <monnier@iro.umontreal.ca>, 41321@debbugs.gnu.org
> 
> On Fri, May 22, 2020 at 7:22 AM Eli Zaretskii <eliz@gnu.org> wrote:
> >   (gdb) p current_buffer->overlays_before
> >   $28 = (struct Lisp_Overlay *) 0x170cb080
> >   (gdb) p $28->start
> >   $29 = XIL(0xa0000000170cb040)
> >   (gdb) xtype
> >   Lisp_Vectorlike
> >   Cannot access memory at address 0x18ac04f8
> 
> Note that didn't try to print $29, but the original invalid marker.

Sorry, I don't follow.  "xtype" shows the type of the last result,
AFAIK, in this case the type of $29.  If this changed somehow, either
we have a bug in .gdbinit or I have been using GDB incorrectly for I
don't know how many years.

What am I missing?