Goal:
    A : Type  P : list A → A → Type  l : list A  a : All_fold P l
  ============================
   (noConfusionHom_All_fold_obligation_1 A P l a a
      (noConfusionHom_All_fold_obligation_2 A P l a a eq_refl) = eq_refl)


DEBUG:Going to execute:
intro_block_id H || intro_block H
Level 3: Backtrace:

No quantified hypothesis named a in current goal even after head-reduction.
Level 3: Backtrace:

No quantified hypothesis named a in current goal even after head-reduction.