Goal:
  
  A : Type
  B : Type
  C : Type
  D : Type
  E : Type
  P : E → A → Type
  Q : C → A → Type
  R : B → D → Type
  f : B → C → E
  b : B
  l : list B
  l''' : list D
  hb : All2 R (b :: l) l'''
  x : C
  y : A
  l0 : list C
  l' : list A
  r : Q x y
  ha : All2 Q l0 l'
  H : #|l| = #|l0|
  ============================
   (let H := CoreTactics.block in
    (∀ (x : B) (y : C) (z : A) (w : D), R x w → Q y z → P (f x y) z)
    → (∀ (l : list B) (l''' : list D),
         All2 R l l''' → #|l| = #|l0| → All2 P (map2 f l l0) l')
      → let H0 := CoreTactics.block in
        All2 P (map2 f (b :: l) (x :: l0)) (y :: l'))


DEBUG:Going to execute:
match goal with
           | |- context [ rew <- [_] eq_refl in _ ] =>
                 progress simpl eq_rect_r
           | |- context [ rew [_] eq_refl in _ ] => progress simpl eq_rect
           | |- context [ Prop.Logic.transport _ eq_refl _ ] =>
                 progress simpl Prop.Logic.transport
           | |- context [ Logic.eq_elim _ _ _ _ _ eq_refl ] =>
                 progress simpl eq_rect
           | |- context [ Logic.eq_elim_r _ _ _ _ eq_refl ] =>
                 progress simpl Logic.eq_elim_r
           | |- context [ noConfusion_inv _ ] =>
                 progress simpl noConfusion_inv
           | |- DepElim.opaque_ind_pack_eq_inv ?G eq_refl =>
                 apply (DepElim.simplify_ind_pack_inv B x p G)
           | |- let _ := CoreTactics.block in _ => fail 1
           | |- _ => simplify * || simplify ?; cbv beta
           | |- _ → ?B =>
                 let ty := type of B in
                 intro || (let H := fresh in
                           intro
                           H)
           | |- ∀ x, _ => let H := fresh x in
                          intro
                          H
           | |- _ => intro
           end