Goal:
  
  A : Type
  x : A
  xs : list A
  f : A → bool
  H0 : (λ (l : list A) (H : ∀ x : A, In x l → bool) (x : bool),
          ∀ (H0 := CoreTactics.block) (f : A → bool) 
            (l0 : list A) (g : ∀ x0 : A, In x0 l0 → bool),
            g = (λ (x0 : A) (_ : In x0 l0), f x0)
            → {| pr1 := l; pr2 := H |} = {| pr1 := l0; pr2 := g |}
              → x = forallb_InP l0 g
                → let H1 := CoreTactics.block in
                  forallb_InP l0 g = forallb f l0) xs
         (λ (x0 : A) (inx : In x0 xs),
            (λ (x1 : A) (_ : In x1 (x :: xs)), f x1) x0
              (forallb_InP_obligations_obligation_2 x xs x0 inx))
         (forallb_InP xs
            (λ (x0 : A) (inx : In x0 xs),
               (λ (x1 : A) (_ : In x1 (x :: xs)), f x1) x0
                 (forallb_InP_obligations_obligation_2 x xs x0 inx)))
  ============================
   (let H := CoreTactics.block in
    forallb_InP (x :: xs) (λ (x0 : A) (_ : In x0 (x :: xs)), f x0) =
    forallb f (x :: xs))


DEBUG:Going to execute:
fail 1

Goals:
    A : Type  f : A → bool
  ============================
   (let H := CoreTactics.block in
    forallb_InP [] (λ (x : A) (_ : In x []), f x) = forallb f [])

  
  A : Type
  x : A
  xs : list A
  f : A → bool
  H0 : (λ (l : list A) (H : ∀ x : A, In x l → bool) (x : bool),
          ∀ (H0 := CoreTactics.block) (f : A → bool) 
            (l0 : list A) (g : ∀ x0 : A, In x0 l0 → bool),
            g = (λ (x0 : A) (_ : In x0 l0), f x0)
            → {| pr1 := l; pr2 := H |} = {| pr1 := l0; pr2 := g |}
              → x = forallb_InP l0 g
                → let H1 := CoreTactics.block in
                  forallb_InP l0 g = forallb f l0) xs
         (λ (x0 : A) (inx : In x0 xs),
            (λ (x1 : A) (_ : In x1 (x :: xs)), f x1) x0
              (forallb_InP_obligations_obligation_2 x xs x0 inx))
         (forallb_InP xs
            (λ (x0 : A) (inx : In x0 xs),
               (λ (x1 : A) (_ : In x1 (x :: xs)), f x1) x0
                 (forallb_InP_obligations_obligation_2 x xs x0 inx)))
  ============================
   (let H := CoreTactics.block in
    forallb_InP (x :: xs) (λ (x0 : A) (_ : In x0 (x :: xs)), f x0) =
    forallb f (x :: xs))


DEBUG:Going to execute:
cbn beta iota
            delta [Prop.Logic.transport Logic.eq_elim Logic.eq_elim_r eq_rect
                  DepElim.pack_sigma_eq DepElim.pack_sigma_eq_nondep] 
            in *
Level 3: Backtrace:

Tactic failure (level 1).
Level 2: Backtrace:

Tactic failure.
Level 1: Backtrace:

Tactic failure.

Goals:
    A : Type  f : A → bool
  ============================
   (let H := CoreTactics.block in
    forallb_InP [] (λ (x : A) (_ : In x []), f x) = forallb f [])

  
  A : Type
  x : A
  xs : list A
  f : A → bool
  H0 : ∀ (H := CoreTactics.block) (f0 : A → bool) 
         (l : list A) (g : ∀ x : A, In x l → bool),
         g = (λ (x : A) (_ : In x l), f0 x)
         → {| pr1 := xs; pr2 := λ (x : A) (_ : In x xs), f x |} =
           {| pr1 := l; pr2 := g |}
           → forallb_InP xs (λ (x : A) (_ : In x xs), f x) = forallb_InP l g
             → let H0 := CoreTactics.block in forallb_InP l g = forallb f0 l
  ============================
   (let H := CoreTactics.block in
    forallb_InP (x :: xs) (λ (x0 : A) (_ : In x0 (x :: xs)), f x0) =
    forallb f (x :: xs))


DEBUG:Going to execute:
DepElim.simplify_IH_hyps

Goals:
    A : Type  f : A → bool
  ============================
   (let H := CoreTactics.block in
    forallb_InP [] (λ (x : A) (_ : In x []), f x) = forallb f [])

  
  A : Type
  x : A
  xs : list A
  f : A → bool
  H0 : ∀ (H := CoreTactics.block) (f0 : A → bool) 
         (l : list A) (g : ∀ x : A, In x l → bool),
         g = (λ (x : A) (_ : In x l), f0 x)
         → {| pr1 := xs; pr2 := λ (x : A) (_ : In x xs), f x |} =
           {| pr1 := l; pr2 := g |}
           → forallb_InP xs (λ (x : A) (_ : In x xs), f x) = forallb_InP l g
             → let H0 := CoreTactics.block in forallb_InP l g = forallb f0 l
  ============================
   (let H := CoreTactics.block in
    forallb_InP (x :: xs) (λ (x0 : A) (_ : In x0 (x :: xs)), f x0) =
    forallb f (x :: xs))


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