Goal:
  
  A : Type
  B : Type
  R : nat → A → B → Type
  n : nat
  b : All2i R n [] []
  H : NoConfusionHom_All2i A B R n [] [] All2i_nil b
  ============================
   (All2i_nil = b)


DEBUG:Going to execute:
match H' with
           | H => idtac
           end
Level 5: H'
 has value 
H

Level 5: Backtrace:

No matching clauses for match.
Level 4: Backtrace:

No matching clauses for match.