Yes, it's a trivial example. I'm not looking to support it, I'm looking to catch it at compile-time. if "Person.FirstName" is a string, then that encourages u

Yes, it's a trivial example. I'm not looking to support it, I'm looking to catch it at compile-time. if "Person.FirstName" is a string, then that encourages users to use string-operations against it, which will fail if this expression is being translated to SQL for executing in the DB. if "Person.FirstName" is some other type with no meaningful operations supported on it (which will get converted into a string when the query is executed) then it prevents many many classes of logic errors.