Goal:
    z : Z  z0 : Z  H : (z <= z0)%Z  H0 : True
  ============================
   (z <= z0)%Z


DEBUG:Going to execute:
Ltac.assumption
Level 3: evaluation returns
<coq-core.plugins.tauto::is_empty@0>
where
tauto_flags := 
of type
tauto_flags
X1 := True
of type
constr of type tacvalue

Level 3: Backtrace:

Tactic failure.
Level 3: Backtrace:

Tactic failure.
Level 2: Backtrace:

Tactic failure.
Level 2: Backtrace:

Tactic failure.