End TagFinType.
Section SumFinType.
Variables T1 T2 : finType.
Definition sum_enum :=
[seq inl _ x | x <- enumF T1] ++ [seq inr _ y | y <- enumF T2].

(* Specifications: *)
Lemma sum_enum_uniq : uniq sum_enum.
Lemma mem_sum_enum u : u \in sum_enum.