[Haskell-cafe] Unification of PolyTypeable TypeReps ?

Hi haskell-cafe In my current project I'm working with type representations created with PolyTypeable, and it turns out that given two type representations I need to find out if they are unifiable. I've looked at polytypeable-utils and see that they have some functions for substituting/applying/free vars, but it doesn't seem like a full solution for what I need. So my question is: is there a library to do this? is there a known way to transform the TypeRep's to make them more amenable to other unification libraries. I noticed that in GHC-api there is an unification library, and that there is also unification-fd. I wanted to ask here first in case someone can point me to the right direction. Thanks! -- Ismael