Goal:
  
  y1 : V.t
  y2 : V.t
  x3 : V.t
  n3 : Z
  y3 : V.t
  H1'' : V.lt y1 y2
  H2'' : V.lt y2 y3
  T1 : V.lt x3 x3 -> V.lt x3 x3 -> V.lt x3 x3
  H0 : V.lt y1 y3
  H1 : n3 = n3
  ============================
   (x3 = x3)


DEBUG:Going to execute:
constructor 1
Level 5: evaluation returns
<coq-core.plugins.tauto::is_unit_or_eq@0>
where
tauto_flags := 
of type
tauto_flags
X1 := x3 = x3
of type
constr of type tacvalue