You mean that Haskell has one of the most complex of the practical type systems known to man. For example (correct me if I am wrong) but the Haskell type system

You mean that Haskell has one of the most complex of the practical type systems known to man. For example (correct me if I am wrong) but the Haskell type system does not allow specification of dependent types (though dependent typing can be simulated after a fashion). Haskell with extensions does have a Turing-complete type system though (I actually don't know what this means, but the internets says so -- perhaps someone can tell me the difference between Haskell and Haskell with extensions).