Goal:
  
  A : Type
  p : A → bool
  q : A → bool
  l : list A
  H0 : ∀ x : A, In x l → p x → q x
  H1 : is_true (forallb p l)
  x : A
  H2 : In x l
  H : ∀ (A : Type) (f : A → bool) (l : list A),
        forallb f l = true → ∀ x : A, In x l → f x = true
  ============================
   (In ?x l)


DEBUG:Going to execute:
eassumption
Level 1: Backtrace:

No applicable tactic.
Level 0: Backtrace:

No applicable tactic.