bug#5973: Crash in get_next_display_element

[Eli Zaretskii <eliz@gnu.org>]

> From: Juanma Barranquero <lekktu@gmail.com>
> Date: Tue, 20 Apr 2010 12:27:00 +0200
> Cc: david.reitter@gmail.com, 5973@debbugs.gnu.org
> 
> AFAICS, the start of etc/NEWS does not contain any composable
> character, just straight ASCII.

The contents of NEWS have nothing to do with this, I think.  The
problematic characters do not come from NEWS, they come from Edebug
trying to display a numeric result as a character.  At least this is
my current theory...

> Hmm. I got a reproducible recipe with -Q
> 
>    emacs -Q
>    M-: (setq force-load-messages t) <RET>
>    C-x C-f bug.el <RET>       ;; the file containing just the defadvice
>    C-u C-M-x
>    C-h n
>    ;; select line 22
>    C-x n n

Right, now I see it as well (except that, the 1st time I use C-x n n,
I need to answer the question about it being disabled; the crash
happens the next time I invoke C-x n n).

So you can forget about all my requests regarding various values in
the crashed frame.

Thanks.