Goal:
    z : t  hd : A.t  tl : list A.t  H : lt (hd :: tl) z
  ============================
   (lt [] z)


DEBUG:Going to execute:
intro_block_id H || intro_block H
Level 0: Backtrace:

No quantified hypothesis named H in current goal even after head-reduction.
Level 0: Backtrace:

No quantified hypothesis named H in current goal even after head-reduction.