accumulate_descendants

# File activesupport/lib/active_support/descendants_tracker.rb, line 45
        def accumulate_descendants(klass, acc)
          if direct_descendants = @@direct_descendants[klass]
            direct_descendants.each do |direct_descendant|
              acc << direct_descendant
              accumulate_descendants(direct_descendant, acc)
            end
          end
        end