# File lib/rspec/core/configuration.rb, line 337
      def filter_run_including(options={}, force_overwrite = false)
        if filter and filter[:line_number] || filter[:full_description]
          warn "Filtering by #{options.inspect} is not possible since " \
               "you are already filtering by #{filter.inspect}"
        else
          if force_overwrite
            self.filter = options
          else
            self.filter = (filter || {}).merge(options)
          end
        end
      end