diff --git a/core/classes/builtin/builtin.factor b/core/classes/builtin/builtin.factor
index c0bc609c13..ad07e00756 100644
--- a/core/classes/builtin/builtin.factor
+++ b/core/classes/builtin/builtin.factor
@@ -11,7 +11,7 @@ PREDICATE: builtin-class < class
 
 : class>type ( class -- n ) "type" word-prop ; foldable
 
-: type>class ( n -- class ) builtins get-global nth ;
+: type>class ( n -- class ) builtins get-global nth ; foldable
 
 : bootstrap-type>class ( n -- class ) builtins get nth ;