Edson - I noticed (lost the JIRA for it) that if you have a fact field of type "Object" - and you do: Foo(someObject < 42) then if at runtime, you make someObject and integer, it fails (class cast exception) as it didn't know what type someObject would be (and it takes a bad guess). What should we do? Should we do some last minute dynamic coercion in the ObjectFactory.java ? Michael.