--- a/contrib/mercurial.el	Thu Apr 12 13:11:30 2007 +0200
+++ b/contrib/mercurial.el	Thu Oct 11 05:58:54 2007 +0900
@@ -521,7 +521,7 @@
 	    (completing-read (format "Revision%s (%s): "
 				     (or prompt "")
 				     (or default "tip"))
-			     (map 'list 'cons revs revs)
+			     (mapcar (lambda (x) (cons x x)) revs)
 			     nil
 			     nil
 			     nil