diff -r 854404b8f738 -r f860b7a98445 src/Pure/codegen.ML
--- a/src/Pure/codegen.ML	Wed Jun 07 02:01:27 2006 +0200
+++ b/src/Pure/codegen.ML	Wed Jun 07 02:01:28 2006 +0200
@@ -558,7 +558,7 @@
 (**** retrieve definition of constant ****)
 
 fun is_instance thy T1 T2 =
-  Sign.typ_instance thy (T1, Type.varifyT T2);
+  Sign.typ_instance thy (T1, Logic.legacy_varifyT T2);
 
 fun get_assoc_code thy s T = Option.map snd (Library.find_first (fn ((s', T'), _) =>
   s = s' andalso is_instance thy T T') (#consts (CodegenData.get thy)));