Goal:
    G : t  z : Z
  ============================
   (z <=? 0 -> exists z0 : Z, Some z = Some z0 /\ z0 <= 0)


DEBUG:Going to execute:
f x
Level 2: evaluation returns
<coq-core.plugins.tauto::with_uniform_flags@0>
where
f := fun flags => <Coq.Init.Tauto.intuition_gen> flags tac
     where
     tac := congruence
     of type
     tacvalue
of type
tacvalue of type tacvalue

Level 1: evaluation returns
<coq-core.plugins.tauto::with_uniform_flags@0>
where
f := fun flags => <Coq.Init.Tauto.intuition_gen> flags tac
     where
     tac := congruence
     of type
     tacvalue
of type
tacvalue of type tacvalue