bug#74771: Native compilation bug with struct predicates when lexical binding enabled (HEAD)

[Eli Zaretskii]

> Cc: 74771@debbugs.gnu.org
> From: Andrea Corallo <acorallo@gnu.org>
> Date: Wed, 11 Dec 2024 17:29:34 -0500
> 
> Eric Marsden <eric.marsden@risk-engineering.org> writes:
> 
> > Hi,
> >
> > With the attached source file, Emacs miscompiles the struct predicate such
> > that a repeated call to the predicate on a non-struct object returns t.
> > This occurs with current HEAD on Linux/AMD64, but not on the Emacs 30.0.92
> > pretest. It does not occur when the lexical binding cookie is not present.
> >
> > % /opt/emacs/bin/emacs -Q --batch --eval "(load (native-compile 
> > \"/tmp/bug.el\"))" -f run
> > Loading 
> > /home/emarsden/.emacs.d/eln-cache/31.0.50-c021c983/bug-59c4b27c-c70072f9.eln
> >  (native compiled elisp)...
> > Running in GNU Emacs 31.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 
> > 3.24.43, cairo version 1.18.2)
> >  of 2024-12-09
> > is? nil
> > is? t   ;; expecting nil
> > bar: 111
> >
> > ;;;   -*- lexical-binding: t -*-
> > ;;
> > ;; /opt/emacs/bin/emacs -Q --batch -L . --eval "(load (native-compile 
> > \"/tmp/bug.el\"))" -f run
> >
> > (require 'cl-lib)
> >
> > (cl-defstruct foobles bar baz)
> >
> > (defun bug (foo)
> >   (message "is? %s" (foobles-p foo))
> >   (message "is? %s" (foobles-p foo))
> >   (message "bar: %s" (foobles-bar foo)))
> >
> > (defun run ()
> >   (message "Running in %s" (version))
> >   (let ((foo "foo"))
> >     (bug foo)))
> 
> Hi Eric,
> 
> thanks for the report, I'll look at this in the coming days.

Any progress here?