assert false (* should not happen *)
| Cic.LetIn _ | Cic.Lambda _ | Cic.Prod _ | Cic.Cast _
| Cic.MutCase _ | Cic.Fix _ | Cic.CoFix _ ->
assert false (* should not happen *)
| Cic.LetIn _ | Cic.Lambda _ | Cic.Prod _ | Cic.Cast _
| Cic.MutCase _ | Cic.Fix _ | Cic.CoFix _ ->