Fixpoint complete_members (env: composite_env) (m: members) : bool :=
match m with
| nil => true
| (id, t) :: m' => complete_type env t && complete_members env m'
end.

(* Specifications: *)
Lemma complete_member:
forall env id t m,
In (id, t) m -> complete_members env m = true -> complete_type env t = true.