| C.Sort s -> C.Sort C.Type (*CSC manca la gestione degli universi!!! *)
| C.Implicit -> raise (Impossible 21)
| C.Cast (te,ty) ->
| C.Sort s -> C.Sort C.Type (*CSC manca la gestione degli universi!!! *)
| C.Implicit -> raise (Impossible 21)
| C.Cast (te,ty) ->