I'm trying to get some information of the kinds of types in a program. In particular, I want to obtain the kinds of arguments to type family instances, that is, given:

type family F a b :: Nat

type instance F (List k) b = b

I would like to obtain the kinds of "k" and "b" in the left-hand side of the type instance.

In particular, I'm obtaining type family instance information via LTyFamInstEqn [http://www.haskell.org/ghc/docs/latest/html/libraries/ghc/HsDecls.html#t:LTyFamInstEqn]. Inside, I get a list of binders of type HsWithBndrs [LHsType name]. I'm assuming each of the LHsTypes inside is a pattern in the type family instance. Thus, I'm looking at those elements and try to find their kind there.

Thus, the specific question is: given a HsType, can I obtain its kind somehow?

Thanks in advance