Goal:
    x : Z  y : Z  H : (x <= y)%Z  H0 : False
  ============================
   False


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