Title: The given variable name already exists
Goal: Generalize the function `swap_add/1' by selecting the subexpression `1', the new parameter name is `N'.
Parameters: [{file,"gen2.erl"},{posrange,{61,61}},{varname,"N"}].
Documentation: Variable `N' is already defined in the body of `swap_app/1', so the name conflict makes the refactoring invalid.
