diff -r 3bd4b3809bee -r 034ebe92f090 src/Tools/Code/code_simp.ML
--- a/src/Tools/Code/code_simp.ML	Thu Jun 17 15:59:46 2010 +0200
+++ b/src/Tools/Code/code_simp.ML	Thu Jun 17 15:59:47 2010 +0200
@@ -51,8 +51,8 @@
 
 fun add_stmt (Code_Thingol.Fun (_, ((_, eqs), some_cong))) ss =
       ss addsimps (map_filter (fst o snd)) eqs addcongs (the_list some_cong)
-  | add_stmt (Code_Thingol.Classinst (_, (_, classparam_insts))) ss =
-      ss addsimps (map (fst o snd) classparam_insts)
+  | add_stmt (Code_Thingol.Classinst (_, (_, (classparam_instances, _)))) ss =
+      ss addsimps (map (fst o snd) classparam_instances)
   | add_stmt _ ss = ss;
 
 val add_program = Graph.fold (add_stmt o fst o snd)