Goal:
  
  elt : Type
  eq_elt : elt -> elt -> Prop
  m : t elt
  m' : t elt
  H : forall x y : key, E.eq x y -> find x m = find y m
  H0 : forall x y : key, E.eq x y -> find x m' = find y m'
  H1 : (forall k : key,
        (exists e : elt, find k m = Some e) <->
        (exists e : elt, find k m' = Some e)) /\
       (forall (k : key) (e e' : elt),
        find k m = Some e -> find k m' = Some e' -> eq_elt e e')
  ============================
   (forall k : key,
    (exists e : elt, find k m' = Some e) ->
    match find k m with
    | Some x =>
        match find k m' with
        | Some y => eq_elt x y
        | None => False
        end
    | None => match find k m' with
              | Some _ => False
              | None => True
              end
    end)


DEBUG:Going to execute:
intros