Goal:
  
  A : Type
  P : list A → list A → A → A → Type
  idx2 : list A
  idx1 : list A
  b : All2_fold P idx2 idx1
  ============================
   (let H := CoreTactics.block in
    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
      {| pr1 := {| pr1 := []; pr2 := [] |}; pr2 := All2_fold_nil P |} =
      {| pr1 := {| pr1 := idx2; pr2 := idx1 |}; pr2 := b |})


DEBUG:Going to execute:
destruct p || (case p; clear p)
Level 6: evaluation of term
raised the exception
Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2_fold P idx2 idx1)"
in
environment:
A : Type
P : list A → list A → A → A → Type
idx2, idx1 : list A
b : All2_fold P idx2 idx1


Level 5: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2_fold P idx2 idx1)"
in
environment:
A : Type
P : list A → list A → A → A → Type
idx2, idx1 : list A
b : All2_fold P idx2 idx1

Level 4: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2_fold P idx2 idx1)"
in
environment:
A : Type
P : list A → list A → A → A → Type
idx2, idx1 : list A
b : All2_fold P idx2 idx1

Level 4: evaluation
raised the exception
Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2_fold P idx2 idx1)"
in
environment:
A : Type
P : list A → list A → A → A → Type
idx2, idx1 : list A
b : All2_fold P idx2 idx1


Level 4: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2_fold P idx2 idx1)"
in
environment:
A : Type
P : list A → list A → A → A → Type
idx2, idx1 : list A
b : All2_fold P idx2 idx1

Level 4: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2_fold P idx2 idx1)"
in
environment:
A : Type
P : list A → list A → A → A → Type
idx2, idx1 : list A
b : All2_fold P idx2 idx1

Level 3: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2_fold P idx2 idx1)"
in
environment:
A : Type
P : list A → list A → A → A → Type
idx2, idx1 : list A
b : All2_fold P idx2 idx1

Level 3: evaluation
raised the exception
Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2_fold P idx2 idx1)"
in
environment:
A : Type
P : list A → list A → A → A → Type
idx2, idx1 : list A
b : All2_fold P idx2 idx1


Level 3: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2_fold P idx2 idx1)"
in
environment:
A : Type
P : list A → list A → A → A → Type
idx2, idx1 : list A
b : All2_fold P idx2 idx1

Level 2: Backtrace:


Could not find an instance for "DepElim.DependentEliminationPackage
                                  (All2_fold P idx2 idx1)"
in
environment:
A : Type
P : list A → list A → A → A → Type
idx2, idx1 : list A
b : All2_fold P idx2 idx1