Definition wt_fundef (fd: fundef) :=
  match fd with
  | Internal f => wt_function ge gtenv f
  | External ef targs tres cc => True
  end.Definition fundef_return (fd: fundef) : type :=
  match fd with
  | Internal f => f.(fn_return)
  | External ef targs tres cc => tres
  end.

Lemma wt_find_funct: forall v fd, Genv.find_funct ge v = Some fd -> wt_fundef fd.