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


DEBUG:Going to execute:
fun flags solver =>
             <Coq.Init.Tauto.tauto_intuit> flags
              ltac:(<Coq.Init.Tauto.reduction_not_iff>) solver