Goal:
  
  A : Type
  B : Type
  R : nat → A → B → Type
  n : nat
  l : list A
  l' : list B
  a : All2i R n l l'
  ============================
   (let H := CoreTactics.block in
    let H0 := CoreTactics.block in
    let H1 := CoreTactics.block in
    All2i
      (λ (i : nat) (x : A) (y : B),
         (if i <? n then False else nth_error l (i - n) = Some x) × R i x y)
      n l l')


DEBUG:Going to execute:
induction p
Level 4: evaluation of term
raised the exception
Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2i R n l l')"
in
environment:
A : Type
B : Type
R : nat → A → B → Type
n : nat
l : list A
l' : list B
a : All2i R n l l'


Level 3: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2i R n l l')"
in
environment:
A : Type
B : Type
R : nat → A → B → Type
n : nat
l : list A
l' : list B
a : All2i R n l l'

Level 2: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2i R n l l')"
in
environment:
A : Type
B : Type
R : nat → A → B → Type
n : nat
l : list A
l' : list B
a : All2i R n l l'

Level 2: evaluation
raised the exception
Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2i R n l l')"
in
environment:
A : Type
B : Type
R : nat → A → B → Type
n : nat
l : list A
l' : list B
a : All2i R n l l'


Level 2: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2i R n l l')"
in
environment:
A : Type
B : Type
R : nat → A → B → Type
n : nat
l : list A
l' : list B
a : All2i R n l l'

Level 2: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2i R n l l')"
in
environment:
A : Type
B : Type
R : nat → A → B → Type
n : nat
l : list A
l' : list B
a : All2i R n l l'

Level 1: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2i R n l l')"
in
environment:
A : Type
B : Type
R : nat → A → B → Type
n : nat
l : list A
l' : list B
a : All2i R n l l'

Level 1: evaluation
raised the exception
Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2i R n l l')"
in
environment:
A : Type
B : Type
R : nat → A → B → Type
n : nat
l : list A
l' : list B
a : All2i R n l l'


Level 1: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2i R n l l')"
in
environment:
A : Type
B : Type
R : nat → A → B → Type
n : nat
l : list A
l' : list B
a : All2i R n l l'

Level 0: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2i R n l l')"
in
environment:
A : Type
B : Type
R : nat → A → B → Type
n : nat
l : list A
l' : list B
a : All2i R n l l'


Goals:
    A : Type  B : Type  R : nat → A → B → Type  n : nat
  ============================
   (let H := CoreTactics.block in
    let H0 := CoreTactics.block in
    let H1 := CoreTactics.block in
    All2i
      (λ (i : nat) (x : A) (y : B),
         (if i <? n then False else nth_error [] (i - n) = Some x) × R i x y)
      n [] [])

  
  A : Type
  B : Type
  R : nat → A → B → Type
  n : nat
  x : A
  y : B
  l : list A
  r : list B
  r0 : R n x y
  a : All2i R (S n) l r
  IHa : let H := CoreTactics.block in
        let H0 := CoreTactics.block in
        let H1 := CoreTactics.block in
        All2i
          (λ (i : nat) (x : A) (y : B),
             (if i <? S n then False else nth_error l (i - S n) = Some x)
             × R i x y) (S n) l r
  ============================
   (let H := CoreTactics.block in
    let H0 := CoreTactics.block in
    let H1 := CoreTactics.block in
    All2i
      (λ (i : nat) (x0 : A) (y : B),
         (if i <? n then False else nth_error (x :: l) (i - n) = Some x0)
         × R i x0 y) n (x :: l) (y :: r))


DEBUG:Going to execute:
CoreTactics.intros_until_block

Goals:
    A : Type  B : Type  R : nat → A → B → Type  n : nat
  ============================
   (let H := CoreTactics.block in
    let H0 := CoreTactics.block in
    let H1 := CoreTactics.block in
    All2i
      (λ (i : nat) (x : A) (y : B),
         (if i <? n then False else nth_error [] (i - n) = Some x) × R i x y)
      n [] [])

  
  A : Type
  B : Type
  R : nat → A → B → Type
  n : nat
  x : A
  y : B
  l : list A
  r : list B
  r0 : R n x y
  a : All2i R (S n) l r
  IHa : let H := CoreTactics.block in
        let H0 := CoreTactics.block in
        let H1 := CoreTactics.block in
        All2i
          (λ (i : nat) (x : A) (y : B),
             (if i <? S n then False else nth_error l (i - S n) = Some x)
             × R i x y) (S n) l r
  ============================
   (let H := CoreTactics.block in
    let H0 := CoreTactics.block in
    let H1 := CoreTactics.block in
    All2i
      (λ (i : nat) (x0 : A) (y : B),
         (if i <? n then False else nth_error (x :: l) (i - n) = Some x0)
         × R i x0 y) n (x :: l) (y :: r))


DEBUG:Going to execute:
match goal with
           | |- let _ := CoreTactics.block in _ => intros _
           | |- _ => try (intro; CoreTactics.intros_until_block)
           end