Definition unit_eqMixin := EqMixin unit_eqP.Canonical unit_eqType := Eval hnf in EqType unit unit_eqMixin.(* Comparison for booleans. *)

(* This is extensionally equal, but not convertible to Bool.eqb. *)
Definition eqb b := addb (~~ b).

Lemma eqbP : Equality.axiom eqb.