-- arguments to the universals of the data constructor
-- (crucial when type checking interfaces)
dict_tys = mkPredTys theta
- result_ty_args = map (substTyVar subst) univ_tvs
+ result_ty_args = substTyVars subst univ_tvs
result_ty = case tyConFamInst_maybe tycon of
-- ordinary constructor
Nothing -> mkTyConApp tycon result_ty_args