gnus-util.el (gnus-macroexpand-all): Don't modify argument.

[bpt/emacs.git] / lisp / gnus / gnus-util.el

diff --git a/lisp/gnus/gnus-util.el b/lisp/gnus/gnus-util.el
index af5159e..1f391f0 100644 (file)
--- a/lisp/gnus/gnus-util.el
+++ b/lisp/gnus/gnus-util.el
@@ -2041,7 +2041,7 @@ Same as `string-match' except this function does not change the match data."
 If no macros are expanded, FORM is returned unchanged."
     (if (consp form)
        (let ((idx 1)
-             (len (length form))
+             (len (length (setq form (copy-sequence form))))
              expanded)
          (while (< idx len)
            (setcar (nthcdr idx form) (gnus-macroexpand-all (nth idx form)))