Goal:
  
  eos : CoreTactics.end_of_section
  fix_0 : ∀ (A B : Type) (l : list A) (f : ∀ x : A, In x l → B),
            map_In_graph A B l f (map_In l f)
  ============================
   (∀ (A B : Type) (l : list A) (f : ∀ x : A, In x l → B),
      map_In_graph A B l f (map_In l f))


DEBUG:Going to execute:
specialize_mutual