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.