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

[Eli Zaretskii]

> From: Pip Cet <pipcet@gmail.com>
> Date: Fri, 29 May 2020 11:47:46 +0000
> Cc: eggert@cs.ucla.edu, Stefan Monnier <monnier@iro.umontreal.ca>, 
> 41321@debbugs.gnu.org
> 
> > There's no bug:
> 
> I believe there is.
> 
> > the $size variable was not updated inside pvectype
> > because the 'set' command tried to access invalid memory.
> 
> Why would pvectype be called at all? xtype should have said
> "Lisp_Symbol", not "Lisp_Vectorlike", and never gotten to pvectype at
> all.

Look at what xtype does, and you will see.