[psygnisfive]

This is really not true at all. Unless what you mean by "implementing type systems for general purpose languages" is a sort of weak, generally useless type system that punishes rather than helps.

This is ESPECIALLY false of Pfenning and co's work, which is aimed specifically at understanding how to apply type theoretic techniques to the design of PLs, so that you get a PL with exactly the sort of stuff you want.

I added a link to the page to PFPL, which is an entire book on how to implement programming languages using type theoretic tools. It even has sections on OO programming, if you're into that sort of thing. It's all the same toolkit, in the end.