Module WFacts_fun (E:DecidableType)(Import M:WSfun E).
Notation eq_dec := E.eq_dec.
Definition eqb x y := if eq_dec x y then true else false.

Lemma eq_option_alt : forall (elt:Type)(o o':option elt),
o=o' <-> (forall e, o=Some e <-> o'=Some e).