normaliseType env (ForAllTy tyvar ty1)
= let (coi,nty1) = normaliseType env ty1
in (mkForAllTyCoI tyvar coi,ForAllTy tyvar nty1)
normaliseType env (ForAllTy tyvar ty1)
= let (coi,nty1) = normaliseType env ty1
in (mkForAllTyCoI tyvar coi,ForAllTy tyvar nty1)