bug#14666: 24.3.50; emacs_backtrace.txt

[Eli Zaretskii]

> From: Juanma Barranquero <lekktu@gmail.com>
> Date: Wed, 19 Jun 2013 17:14:43 +0200
> Cc: 14666@debbugs.gnu.org
> 
> 0x011ecbac: w32_backtrace at w32fns.c:7741
> 0x011ecc1e: emacs_abort at w32fns.c:7773
> 0x010d9fe0: terminate_due_to_signal at emacs.c:350
> 0x01151719: die at alloc.c:6520
> 0x01147b6b: XBUFFER at lisp.h:820
> 0x011e3ac1: w32_wnd_proc at w32fns.c:3189

I don't get it: it crashes here:

  LISP_INLINE struct buffer *
  XBUFFER (Lisp_Object a)
  {
    eassert (BUFFERP (a));
    return XUNTAG (a, Lisp_Vectorlike);  <<<<<<<<<<<<<<<
  }

I don't see how XUNTAG can crash, so the only possible cause that's
left is the assertion before that.  But how can the assertion be
false, when line 3189 of w32fns.c is only executed if w->contents _is_
a buffer?