anchor.diff:  %% @see c_call/3
   %% @see call_args/1
   
  --spec call_arity(c_call()) -> non_neg_integer().
  +-spec call_arity(c_call()) -> arity().
   
   call_arity(Node) ->
       length(call_args(Node)).
  
positive.code: %% @see c_fun/2
  %% @see fun_vars/1
  
  -spec fun_arity(c_fun()) -> non_neg_integer().
  
  fun_arity(Node) ->
      length(fun_vars(Node)).
  
negative.code: %% @see ann_c_fname/3
  %% @see update_c_fname/3
  
  -spec c_fname(atom(), arity()) -> c_var().
  
  c_fname(Atom, Arity) ->
      c_var({Atom, Arity}).
  
  
  %% @spec ann_c_fname(As::[term()], Name::atom(), Arity::arity()) ->
  %%           cerl()
  %% @equiv ann_c_var(As, {Atom, Arity})
  %% @see c_fname/2
  
  -spec ann_c_fname([term()], atom(), arity()) -> c_var().
  
  ann_c_fname(As, Atom, Arity) ->
      ann_c_var(As, {Atom, Arity}).
  