--- a/src/Pure/Syntax/type_ext.ML Fri Feb 01 08:32:10 2008 +0100
+++ b/src/Pure/Syntax/type_ext.ML Fri Feb 01 08:32:26 2008 +0100
@@ -39,8 +39,10 @@
let
fun classes (Const (c, _)) = [c]
| classes (Free (c, _)) = [c]
+ | classes (Const ("_class",_) $ Free (c, _)) = [c]
| classes (Const ("_classes", _) $ Const (c, _) $ cs) = c :: classes cs
| classes (Const ("_classes", _) $ Free (c, _) $ cs) = c :: classes cs
+ | classes (Const ("_classes", _) $ (Const ("_class",_) $ Free (c, _)) $ cs) = c :: classes cs
| classes tm = raise TERM ("sort_of_term: bad encoding of classes", [tm]);
fun sort (Const ("_topsort", _)) = []