tyVarsOfTypeAcc

[Richard Eisenberg]

Hi devs,

I'm (once again) merging master into my type=kind branch. I see that we now have tyVarsOfTypeAcc :: Type -> FV, distinct from tyVarsOfType :: Type -> TyVarSet. I trust that this new version is more performant. However, I have a question: in the implementation of these functions, the three extra FV parameters (fv_cand in_scope acc) are bound and passed each time. 

Why?

I've always understood that eta-reducing in function definitions is better than expanding. Or is this just a style choice?

Thanks,
Richard