Goal:
  
  A : Type
  p : A → bool
  a : A
  l : list A
  IHl : ∀ n : nat, nth_error l n = Some a → forallb p l → p a
  H : p a ∧ forallb p l
  ============================
   (is_true (p a))


DEBUG:Going to execute:
exact H || destruct_hyp H
DEBUG LTAC Evaluated term: H
DEBUG LTAC Evaluated term: (p a ∧ forallb p l)
Level 2: type of H
 has value 
(p a ∧ forallb p l)