Subject: Re: bug#46586: 26.3, 27.1.50; Emacs crash in a backtrace (core) dump (a long standing issue)

From: Eli Zaretskii <[email-masked]>
Date: Wed, 17 Feb 2021 18:04:37 +0200

> From: 路客 <[email-masked]>
> Date: Wed, 17 Feb 2021 18:13:56 +0800
> 
> ----- code begin -----
> (#1=(#("000008964 .gnus.el" 0 18 (r #1#))
> (def #2=#("000008964 .gnus.el" 0 18
> (r
> (#2#
> (def #3=#("000006393 .gnus.el" 0 18
> (r #4=(#3#
> (def
> #("000006393 .gnus.el" 0 18 (r #4#)) "x"))))"x"))))"x")))
> ----- code end -----
> 
> Try to `read' or `eval' this block of code (C-x C-e) will immediately
> crash Emacs 26.3 or 27.1.50; however, older Emacs 26.0.50 works well
> by entering the debugger with an error like:

It's an infinite recursion in substitute_object_recurse, called by
lread--substitute-object-in-subtree.