--- a/mercurial/fileset.py	Wed Aug 15 22:28:32 2012 +0200
+++ b/mercurial/fileset.py	Wed Aug 15 22:50:23 2012 +0200
@@ -485,7 +485,7 @@
             subset.extend(c)
     else:
         status = None
-        subset = ctx.walk(ctx.match([]))
+        subset = list(ctx.walk(ctx.match([])))
 
     return getset(matchctx(ctx, subset, status), tree)