Goal:
  
  A : Type
  P : A → Type
  p : A → bool
  q : A → bool
  x : A
  l : list A
  p0 : P x
  X : All P l
  H : ∀ x : A, P x → p x = q x
  H0 : forallb p l = forallb q l
  ============================
   (p x && forallb p l = q x && forallb q l)


DEBUG:Going to execute:
<Coq.Init.Tauto.is_empty> flags X1; elim H
Level 2: Backtrace:

In environment
A : Type
P : A → Type
p, q : A → bool
x : A
l : list A
p0 : P x
X : All P l
H : ∀ x : A, P x → p x = q x
H0 : forallb p l = forallb q l
Unable to unify "q x && forallb q l" with "p x && forallb p l".
Level 2: Backtrace:

In environment
A : Type
P : A → Type
p, q : A → bool
x : A
l : list A
p0 : P x
X : All P l
H : ∀ x : A, P x → p x = q x
H0 : forallb p l = forallb q l
Unable to unify "q x && forallb q l" with "p x && forallb p l".
Level 3: Backtrace:

In environment
A : Type
P : A → Type
p, q : A → bool
x : A
l : list A
p0 : P x
X : All P l
H : ∀ x : A, P x → p x = q x
H0 : forallb p l = forallb q l
Unable to unify "q x && forallb q l" with "p x && forallb p l".
Level 3: Backtrace:

In environment
A : Type
P : A → Type
p, q : A → bool
x : A
l : list A
p0 : P x
X : All P l
H : ∀ x : A, P x → p x = q x
H0 : forallb p l = forallb q l
Unable to unify "q x && forallb q l" with "p x && forallb p l".
Level 2: Backtrace:

In environment
A : Type
P : A → Type
p, q : A → bool
x : A
l : list A
p0 : P x
X : All P l
H : ∀ x : A, P x → p x = q x
H0 : forallb p l = forallb q l
Unable to unify "q x && forallb q l" with "p x && forallb p l".
Level 2: Backtrace:

In environment
A : Type
P : A → Type
p, q : A → bool
x : A
l : list A
p0 : P x
X : All P l
H : ∀ x : A, P x → p x = q x
H0 : forallb p l = forallb q l
Unable to unify "q x && forallb q l" with "p x && forallb p l".