[gpderetta]

> is Haskell's Hindley-Milner type identification system Turing complete?

I'm out of my depth, but I'm pretty sure HM is not Turing complete by design as otherwise it wouldn't be able to guarantee that inference completes. An HM type system is about as powerful you can get without being Turing complete.

There are extensions to the type systems of languages that use HM making them Turing complete, but when using those extensions inference is not guaranteed or doesn't work at all.