Haskell and SML both have sufficiently expressive type systems that I do not ever find myself writing correct code that fails to typecheck. If the code fails to

Haskell and SML both have sufficiently expressive type systems that I do not ever find myself writing correct code that fails to typecheck. If the code fails to typecheck, I have done something wrong. (If the code does typecheck, then I have guaranteed a lot of static properties of my code, but it may still be incorrect in terms of dynamic semantics.)