Goal:
  
  A : Type
  P : list A → list A → A → A → Type
  d : A
  d' : A
  Γ : list A
  Γ' : list A
  a : All2_fold P Γ Γ'
  p : P Γ Γ' d d'
  idx2 : list A
  idx1 : list A
  b : All2_fold P idx2 idx1
  e : NoConfusion_All2_fold A P
        {|
          pr1 := {| pr1 := d :: Γ; pr2 := d' :: Γ' |};
          pr2 := All2_fold_cons P a p
        |} {| pr1 := {| pr1 := idx2; pr2 := idx1 |}; pr2 := b |}
  ============================
   (noConfusion_All2_fold_obligation_2 A P
      {|
        pr1 := {| pr1 := d :: Γ; pr2 := d' :: Γ' |};
        pr2 := All2_fold_cons P a p
      |} {| pr1 := {| pr1 := idx2; pr2 := idx1 |}; pr2 := b |}
      (noConfusion_All2_fold_obligation_1 A P
         {|
           pr1 := {| pr1 := d :: Γ; pr2 := d' :: Γ' |};
           pr2 := All2_fold_cons P a p
         |} {| pr1 := {| pr1 := idx2; pr2 := idx1 |}; pr2 := b |} e) = e)


DEBUG:Going to execute:
intro_block_id H
DEBUG LTAC Evaluated term: (∀ (H := CoreTactics.block) 
                              (e : NoConfusion_All2_fold A P
                                     {|
                                       pr1 := {| pr1 := []; pr2 := [] |};
                                       pr2 := All2_fold_nil P
                                     |}
                                     {|
                                       pr1 := {| pr1 := idx2; pr2 := idx1 |};
                                       pr2 := b
                                     |}),
                              let H0 := CoreTactics.block in
                              noConfusion_All2_fold_obligation_2 A P
                                {|
                                  pr1 := {| pr1 := []; pr2 := [] |};
                                  pr2 := All2_fold_nil P
                                |}
                                {|
                                  pr1 := {| pr1 := idx2; pr2 := idx1 |};
                                  pr2 := b
                                |}
                                (noConfusion_All2_fold_obligation_1 A P
                                   {|
                                     pr1 := {| pr1 := []; pr2 := [] |};
                                     pr2 := All2_fold_nil P
                                   |}
                                   {|
                                     pr1 := {| pr1 := idx2; pr2 := idx1 |};
                                     pr2 := b
                                   |} e) = e)