Goal:
  
  hd : A.t
  tl'0 : t
  tl : t
  tl' : t
  H : lt_ tl tl'
  IHlt_ : forall z : t, lt tl' z -> lt tl z
  H' : lt_ tl' tl'0
  ============================
   (lt tl' tl'0)


DEBUG:Going to execute:
solve
[ trivial
with eq_true
| Ltac.reflexivity
| Ltac.symmetry; trivial
| contradiction ]