Goal:
  
  A : Type
  B : Type
  C : Type
  Q : C → Type
  P : C → A → Prop
  fn : ∀ x : A, (∀ y : C, Q y → P y x) → B
  Hl : ∀ y : C, Q y → ∥ All (P y) [] ∥
  n : nat
  x : A
  H2 : option A
  H0 : None = H2
  ============================
   (Some x = H2
    → let H := CoreTactics.block in
      let H0 := CoreTactics.block in
      ∃ D : ∀ y : C, Q y → P y x,
        nth_error (map_All fn [] Hl) (S n) = Some (fn x D))


DEBUG:Going to execute:
destruct p || (case p; clear p)
Level 4: evaluation of term
raised the exception
Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (None = H2)"
in
environment:
A : Type
B : Type
C : Type
Q : C → Type
P : C → A → Prop
fn : ∀ x : A, (∀ y : C, Q y → P y x) → B
Hl : ∀ y : C, Q y → ∥ All (P y) [] ∥
n : nat
x : A
H2 : option A
H0 : None = H2


Level 3: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (None = H2)"
in
environment:
A : Type
B : Type
C : Type
Q : C → Type
P : C → A → Prop
fn : ∀ x : A, (∀ y : C, Q y → P y x) → B
Hl : ∀ y : C, Q y → ∥ All (P y) [] ∥
n : nat
x : A
H2 : option A
H0 : None = H2

Level 2: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (None = H2)"
in
environment:
A : Type
B : Type
C : Type
Q : C → Type
P : C → A → Prop
fn : ∀ x : A, (∀ y : C, Q y → P y x) → B
Hl : ∀ y : C, Q y → ∥ All (P y) [] ∥
n : nat
x : A
H2 : option A
H0 : None = H2

Level 2: evaluation
raised the exception
Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (None = H2)"
in
environment:
A : Type
B : Type
C : Type
Q : C → Type
P : C → A → Prop
fn : ∀ x : A, (∀ y : C, Q y → P y x) → B
Hl : ∀ y : C, Q y → ∥ All (P y) [] ∥
n : nat
x : A
H2 : option A
H0 : None = H2


Level 2: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (None = H2)"
in
environment:
A : Type
B : Type
C : Type
Q : C → Type
P : C → A → Prop
fn : ∀ x : A, (∀ y : C, Q y → P y x) → B
Hl : ∀ y : C, Q y → ∥ All (P y) [] ∥
n : nat
x : A
H2 : option A
H0 : None = H2

Level 2: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (None = H2)"
in
environment:
A : Type
B : Type
C : Type
Q : C → Type
P : C → A → Prop
fn : ∀ x : A, (∀ y : C, Q y → P y x) → B
Hl : ∀ y : C, Q y → ∥ All (P y) [] ∥
n : nat
x : A
H2 : option A
H0 : None = H2

Level 1: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (None = H2)"
in
environment:
A : Type
B : Type
C : Type
Q : C → Type
P : C → A → Prop
fn : ∀ x : A, (∀ y : C, Q y → P y x) → B
Hl : ∀ y : C, Q y → ∥ All (P y) [] ∥
n : nat
x : A
H2 : option A
H0 : None = H2

Level 1: evaluation
raised the exception
Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (None = H2)"
in
environment:
A : Type
B : Type
C : Type
Q : C → Type
P : C → A → Prop
fn : ∀ x : A, (∀ y : C, Q y → P y x) → B
Hl : ∀ y : C, Q y → ∥ All (P y) [] ∥
n : nat
x : A
H2 : option A
H0 : None = H2


Level 1: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (None = H2)"
in
environment:
A : Type
B : Type
C : Type
Q : C → Type
P : C → A → Prop
fn : ∀ x : A, (∀ y : C, Q y → P y x) → B
Hl : ∀ y : C, Q y → ∥ All (P y) [] ∥
n : nat
x : A
H2 : option A
H0 : None = H2

Level 0: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (None = H2)"
in
environment:
A : Type
B : Type
C : Type
Q : C → Type
P : C → A → Prop
fn : ∀ x : A, (∀ y : C, Q y → P y x) → B
Hl : ∀ y : C, Q y → ∥ All (P y) [] ∥
n : nat
x : A
H2 : option A
H0 : None = H2