Section tbled.
Variable tbl : SymEnv.functions RType_typ.
Let RSym_sym := RSym_sym tbl.
Existing Instance RSym_sym.
Let RSym_sym_ok :  RSymOk RSym_sym := _.
Existing Instance RSym_sym_ok.
Let Expr_expr_fs := Expr_expr_fs tbl.
Existing Instance Expr_expr_fs.
Let Expr_ok_fs := Expr_ok_fs tbl.
Existing Instance Expr_ok_fs.
Existing Instance MA.
Definition reflect tus tvs e (ty : typ)
:= @exprD _ _ _ Expr_expr_fs tus tvs e ty.
intros. congruence.
Qed.

Lemma as_tree_l : forall e t l o r,
as_tree e = Some (inl (t, l, o, r)) ->
e = (App (App (App (Inj (inr (Data (fnode t)))) l) o) r).