--- a/src/Pure/Isar/toplevel.ML Tue Jul 20 14:41:13 2010 +0200
+++ b/src/Pure/Isar/toplevel.ML Tue Jul 20 14:44:33 2010 +0200
@@ -699,7 +699,7 @@
val states =
(case States.get (presentation_context_of st'') of
- NONE => sys_error ("No future states for " ^ name_of tr ^ Position.str_of (pos_of tr))
+ NONE => raise Fail ("No future states for " ^ name_of tr ^ Position.str_of (pos_of tr))
| SOME states => states);
val result = Lazy.lazy
(fn () => (tr, st') :: (body_trs ~~ Future.join states) @ [(end_tr, st'')]);