--- a/mercurial/ignore.py	Tue Feb 15 22:25:48 2011 +0100
+++ b/mercurial/ignore.py	Thu Feb 03 10:31:17 2011 +0100
@@ -86,7 +86,8 @@
                      (f, inst.strerror))
 
     allpats = []
-    [allpats.extend(patlist) for patlist in pats.values()]
+    for patlist in pats.values():
+        allpats.extend(patlist)
     if not allpats:
         return util.never