GNU bug report logs - #27016
possible bug in `defsetf'

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Message #13 received at 27016 <at> debbugs.gnu.org (full text, mbox):

From: Rafael D Sorkin <rsorkin <at> perimeterinstitute.ca>
To: npostavs <at> users.sourceforge.net
Cc: 27016 <at> debbugs.gnu.org, Rafael D Sorkin <rsorkin <at> perimeterinstitute.ca>
Subject: Re: bug#27016: possible bug in `defsetf'
Date: Mon, 22 May 2017 16:25:14 -0400

Hi Noam,

Following your suggestion I tried starting with "emacs -Q" and
got the same results as you did.  However if I (require 'cl)
then the bug returns.  (I normally require CL automatically on
starting emacs.)  So perhaps it's an incompatibility between CL
and the new way that defsetf is implemented.

- Rafael

 > Sender: Noam Postavsky <npostavs <at> gmail.com>
 > From: npostavs <at> users.sourceforge.net
 > To: Rafael D Sorkin <rsorkin <at> perimeterinstitute.ca>
 > Cc: 27016 <at> debbugs.gnu.org
 > Subject: Re: bug#27016: possible bug in `defsetf'
 > Date: Mon, 22 May 2017 08:11:25 -0400
 > In-Reply-To: <E1dCh04-0001Bd-Ec <at> mars.pi.local> (Rafael D. Sorkin's message of
 >  "Mon, 22 May 2017 02:39:28 -0400")
 > User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.2 (gnu/linux)
 > 
 > tags 27016 unreproducible
 > quit
 > 
 > Rafael D Sorkin <rsorkin <at> perimeterinstitute.ca> writes:
 > 
 > > emacs-version				; 24.5.1
 > > (setq pair (cons 3 4))			; (3 . 4)
 > > (foobar pair)				; Symbol's function definition is void: foobar
 > > (setf (foobar pair) 0)			; (foobar pair) is not a valid place expression 
 > > (unless t
 > >   (defalias 'foobar 'cons)
 > >   (defsetf foobar setcar))		; nil 
 > > (foobar pair)				; same as above
 > > (setf (foobar pair) 0)			; 0       !
 > > pair					; (0 . 4) !
 > 
 > I'm not able to reproduce this behaviour on 24.5, the second setf throws
 > an error just like the first.  How are you evaluating these exactly
 > (starting from emacs -Q)?  I tried C-x C-e on each sexp in turn.

~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-
 Rafael Sorkin
 Perimeter Institute for Theoretical Physics
 31 Caroline Street North
 Waterloo, ON  N2L 2Y5
 Canada
~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-

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