Goal:
    hd : A.t  tl' : t  tl : list A.t  H : lt_ tl tl'
  ============================
   (let H := CoreTactics.block in
    let H0 := CoreTactics.block in lt [] (hd :: tl'))


DEBUG:Going to execute:
fail 1

Goals:
    hd' : A.t  tl' : list A.t  hd : A.t  tl : list A.t  H : A.lt hd hd'
  ============================
   (let H := CoreTactics.block in
    let H0 := CoreTactics.block in lt [] (hd' :: tl'))

    hd : A.t  tl' : t  tl : list A.t  H : lt_ tl tl'
  ============================
   (let H := CoreTactics.block in
    let H0 := CoreTactics.block in lt [] (hd :: tl'))


DEBUG:Going to execute:
DepElim.simplify_IH_hyps
Level 2: Backtrace:

Tactic failure (level 1).
Level 1: Backtrace:

Tactic failure.
Level 0: Backtrace:

Tactic failure.

Goals:
    hd' : A.t  tl' : list A.t  hd : A.t  tl : list A.t  H : A.lt hd hd'
  ============================
   (let H := CoreTactics.block in
    let H0 := CoreTactics.block in lt [] (hd' :: tl'))

    hd : A.t  tl' : t  tl : list A.t  H : lt_ tl tl'
  ============================
   (let H := CoreTactics.block in
    let H0 := CoreTactics.block in lt [] (hd :: tl'))


DEBUG:Going to execute:
repeat
            match goal with
            | hyp:context [ CoreTactics.block ]
              |- _ =>
                  cbn beta in hyp; eqns_specialize_eqs_block hyp;
                   cbn[eq_rect_r eq_rect] in hyp
            end