From: Stefan Monnier <monnier@iro.umontreal.ca>
Date: Thu, 6 Nov 2014 03:27:23 +0000 (-0500)
Subject: * lisp/subr.el (pop): Don't call the getter twice.
X-Git-Tag: emacs-25.0.90~2635^2~555
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=577ef0bc58b5e8fd048bcc5bae8c34c4020fa2cc;p=emacs.git

* lisp/subr.el (pop): Don't call the getter twice.

Fixes: debbugs:18968
---

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 91a076e20e5..7dc4786aff5 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,5 +1,7 @@
 2014-11-06  Stefan Monnier  <monnier@iro.umontreal.ca>
 
+	* subr.el (pop): Don't call the getter twice (bug#18968).
+
 	* emacs-lisp/macroexp.el (macroexp--expand-all): Optimize away trivial
 	uses of `funcall'.
 
diff --git a/lisp/subr.el b/lisp/subr.el
index 55ff739fec5..6ce02b79a0a 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -169,7 +169,8 @@ change the list."
          ;; So we can use `pop' in the bootstrap before `gv' can be used.
          (list 'prog1 place (list 'setq place (list 'cdr place)))
        (gv-letplace (getter setter) place
-         `(prog1 ,getter ,(funcall setter `(cdr ,getter)))))))
+         (macroexp-let2 macroexp-copyable-p x getter
+           `(prog1 ,x ,(funcall setter `(cdr ,x))))))))
 
 (defmacro when (cond &rest body)
   "If COND yields non-nil, do BODY, else return nil.