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
  ============================
   (q x = true)


DEBUG:Going to execute:
eapply forallb_forall in H1
DEBUG LTAC Evaluated term: forallb_forall

Goals:
  
  A : Type
  p : A → bool
  q : A → bool
  l : list A
  H0 : ∀ x : A, In x l → p x → q x
  x : A
  H2 : In x l
  H1 : p ?x = true
  ============================
   (q x = true)

  
  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:
try eassumption
DEBUG LTAC Evaluated term: forallb_forall