Goal:
    A : Type  B : Type  C : Type  R : A → C → Type  g : A → B → C
  ============================
   (All2 (λ (x : A) (y : B), R x (g x y)) [] [] → All2 R [] [])


DEBUG:Going to execute:
done
DEBUG LTAC Evaluated term: l'
DEBUG LTAC Evaluated term: l
DEBUG LTAC Evaluated term: l