Goal:
    G : t  z : Z  le : z <= 0
  ============================
   (Some z = Some z /\ z <= 0)


DEBUG:Going to execute:
Ltac.split
Level 2: evaluation returns
<coq-core.plugins.tauto::is_conj@0>
where
tauto_flags := 
of type
tauto_flags
X1 := Some z = Some z /\ z <= 0
of type
constr of type tacvalue