Goal:
  
  x : V.t
  n : Z
  y : V.t
  H : V.lt x x \/ V.eq x x /\ n < n \/ V.eq x x /\ n = n /\ V.lt y y
  ============================
   False


DEBUG:Going to execute:
PTRDEBUGTAC<Coq.Init.Tauto.is_conj> flags X1; elim id; do 2 intro; clear id
Level 2: evaluation returns
<coq-core.plugins.tauto::is_conj@0>
where
tauto_flags := 
of type
tauto_flags
X1 := Z
of type
constr of type tacvalue

Level 2: Backtrace:

Tactic failure.
Level 2: Backtrace:

Tactic failure.
Level 1: Backtrace:

Tactic failure.
Level 1: Backtrace:

Tactic failure.
Level 1: Backtrace:

Tactic failure.
Level 1: Backtrace:

Tactic failure.