Goal:
  
  A : Type
  B : Type
  R : A → B → Prop
  H : ∀ (x : A) (y : B), R x y
  e : 0 = #|[]|
  ============================
   (Forall2 R [] [])


DEBUG:Going to execute:
<coq-core.plugins.ltac::discriminate@1> $1