Goal:
  
  A : Type
  B : Type
  I : Type
  I' : Type
  P : I' → B → B → Type
  g : I → I'
  f : A → B
  b : I
  bs : list I
  hd : A
  tl : list A
  tl' : list A
  X : OnOne2All (λ i : I, on_Trel (P (g i)) f) bs tl tl'
  IHX : OnOne2All P (map g bs) (map f tl) (map f tl')
  ============================
   (OnOne2All P (map g bs) (map f tl) (map f tl'))


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

Tactic failure: congruence failed.
Level 0: Backtrace:

Tactic failure: congruence failed.