Goal:
  
  A : Type
  B : Type
  C : Type
  R : A → B → C → Type
  l0 : list A
  l1 : list B
  l : list C
  a : All3 R l0 l1 l
  ============================
   (NoConfusionHom_All3 A B C R l0 l1 l a a)


DEBUG:Going to execute:
idtac
DEBUG LTAC Evaluated term: a
DEBUG LTAC Evaluated term: (All3 R l0 l1 l)
Level 5: type of id
 has value 
(All3 R l0 l1 l)