Goal:
  
  A : Type
  B : Type
  R : nat → A → B → Type
  H : ∀ (n : nat) (x : A) (y : B), R n x y
  n : nat
  ============================
   (0 = 0 → All2i R n [] [])


DEBUG:Going to execute:
<coq-core.plugins.ltac::discriminate@0>