Goal:
  
  A : Type
  B : Type
  p : A → B → bool
  b : B
  l' : list B
  H : is_true false
  ============================
   (All2 (λ (x : A) (y : B), p x y) [] (b :: l'))


DEBUG:Going to execute:
congruence
Level 0: Backtrace:

Tactic failure: congruence failed.
Level 0: Backtrace:

Tactic failure: congruence failed.