through_scope

# File activerecord/lib/active_record/associations/preloader/through_association.rb, line 43
        def through_scope
          through_scope = through_reflection.klass.unscoped

          if options[:source_type]
            through_scope.where! reflection.foreign_type => options[:source_type]
          else
            unless reflection_scope.where_values.empty?
              through_scope.includes_values = Array(reflection_scope.values[:includes] || options[:source])
              through_scope.where_values    = reflection_scope.values[:where]
            end

            through_scope.references! reflection_scope.values[:references]
            through_scope.order! reflection_scope.values[:order] if through_scope.eager_loading?
          end

          through_scope
        end