Goal:
  
  A : Type
  B : Type
  f : A → B
  a : A
  l' : list A
  h : ∀ x y : A, f x = f y → x = y
  e : map f [] = map f (a :: l')
  ============================
   ([] = a :: l')


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

No primitive equality found.
Level 0: Backtrace:

No primitive equality found.