Hindley-Milner type inference is unification over types and unification is built-in to Prolog. Functional programmers ignore this because their textbooks never refer to the original description of unification by Robinson. Wait who? Unification was probably invented by Damas, Hindley or Milner right? Or maybe Haskell Curry? Hey maybe it was John McCarthy?
In any case, what was suggested is, frankly, a development of the (tailored up) type system.
My experiece suggests that this development will not be without caveats, especially related to performance.