diff --git a/actionpack/lib/action_controller/abstract/benchmarker.rb b/actionpack/lib/action_controller/abstract/benchmarker.rb
index 9be06f48fb..6999329144 100644
--- a/actionpack/lib/action_controller/abstract/benchmarker.rb
+++ b/actionpack/lib/action_controller/abstract/benchmarker.rb
@@ -1,6 +1,6 @@
 module AbstractController
   module Benchmarker
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     depends_on Logger
 
diff --git a/actionpack/lib/action_controller/abstract/callbacks.rb b/actionpack/lib/action_controller/abstract/callbacks.rb
index 4314235ba9..6c67315c58 100644
--- a/actionpack/lib/action_controller/abstract/callbacks.rb
+++ b/actionpack/lib/action_controller/abstract/callbacks.rb
@@ -1,6 +1,6 @@
 module AbstractController
   module Callbacks
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     depends_on ActiveSupport::NewCallbacks
 
diff --git a/actionpack/lib/action_controller/abstract/helpers.rb b/actionpack/lib/action_controller/abstract/helpers.rb
index 7b1b197e1d..43832f1e2d 100644
--- a/actionpack/lib/action_controller/abstract/helpers.rb
+++ b/actionpack/lib/action_controller/abstract/helpers.rb
@@ -1,6 +1,6 @@
 module AbstractController
   module Helpers
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     depends_on Renderer
 
diff --git a/actionpack/lib/action_controller/abstract/layouts.rb b/actionpack/lib/action_controller/abstract/layouts.rb
index dd38485271..b3f21f7b22 100644
--- a/actionpack/lib/action_controller/abstract/layouts.rb
+++ b/actionpack/lib/action_controller/abstract/layouts.rb
@@ -1,6 +1,6 @@
 module AbstractController
   module Layouts
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     depends_on Renderer
 
diff --git a/actionpack/lib/action_controller/abstract/logger.rb b/actionpack/lib/action_controller/abstract/logger.rb
index ce73888763..d6fa843485 100644
--- a/actionpack/lib/action_controller/abstract/logger.rb
+++ b/actionpack/lib/action_controller/abstract/logger.rb
@@ -3,7 +3,7 @@ require 'active_support/core_ext/logger'
 
 module AbstractController
   module Logger
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     class DelayedLog
       def initialize(&blk)
diff --git a/actionpack/lib/action_controller/abstract/renderer.rb b/actionpack/lib/action_controller/abstract/renderer.rb
index 374ceb5b74..cd3e87d861 100644
--- a/actionpack/lib/action_controller/abstract/renderer.rb
+++ b/actionpack/lib/action_controller/abstract/renderer.rb
@@ -2,7 +2,7 @@ require "action_controller/abstract/logger"
 
 module AbstractController
   module Renderer
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     depends_on AbstractController::Logger
 
diff --git a/actionpack/lib/action_controller/base/chained/flash.rb b/actionpack/lib/action_controller/base/chained/flash.rb
index 2d084ba1ab..04d27bf090 100644
--- a/actionpack/lib/action_controller/base/chained/flash.rb
+++ b/actionpack/lib/action_controller/base/chained/flash.rb
@@ -26,7 +26,7 @@ module ActionController #:nodoc:
   #
   # See docs on the FlashHash class for more details about the flash.
   module Flash
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     # TODO : Remove the defined? check when new base is the main base
     depends_on Session if defined?(ActionController::Http)
diff --git a/actionpack/lib/action_controller/base/filter_parameter_logging.rb b/actionpack/lib/action_controller/base/filter_parameter_logging.rb
index f5a678ca03..9df286ee24 100644
--- a/actionpack/lib/action_controller/base/filter_parameter_logging.rb
+++ b/actionpack/lib/action_controller/base/filter_parameter_logging.rb
@@ -1,6 +1,6 @@
 module ActionController
   module FilterParameterLogging
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     # TODO : Remove the defined? check when new base is the main base
     if defined?(ActionController::Http)
diff --git a/actionpack/lib/action_controller/base/helpers.rb b/actionpack/lib/action_controller/base/helpers.rb
index 96fa7896a9..f74158bc13 100644
--- a/actionpack/lib/action_controller/base/helpers.rb
+++ b/actionpack/lib/action_controller/base/helpers.rb
@@ -3,7 +3,7 @@ require 'active_support/dependencies'
 # FIXME: helper { ... } is broken on Ruby 1.9
 module ActionController #:nodoc:
   module Helpers #:nodoc:
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     included do
       # Initialize the base module to aggregate its helpers.
diff --git a/actionpack/lib/action_controller/base/request_forgery_protection.rb b/actionpack/lib/action_controller/base/request_forgery_protection.rb
index 0a0e20e1f1..368c6e9de8 100644
--- a/actionpack/lib/action_controller/base/request_forgery_protection.rb
+++ b/actionpack/lib/action_controller/base/request_forgery_protection.rb
@@ -3,7 +3,7 @@ module ActionController #:nodoc:
   end
 
   module RequestForgeryProtection
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     # TODO : Remove the defined? check when new base is the main base
     if defined?(ActionController::Http)
diff --git a/actionpack/lib/action_controller/base/streaming.rb b/actionpack/lib/action_controller/base/streaming.rb
index 5872ba99a2..5f56c95483 100644
--- a/actionpack/lib/action_controller/base/streaming.rb
+++ b/actionpack/lib/action_controller/base/streaming.rb
@@ -2,7 +2,7 @@ module ActionController #:nodoc:
   # Methods for sending arbitrary data and for streaming files to the browser,
   # instead of rendering.
   module Streaming
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     # TODO : Remove the defined? check when new base is the main base
     if defined?(ActionController::Http)
diff --git a/actionpack/lib/action_controller/base/verification.rb b/actionpack/lib/action_controller/base/verification.rb
index 3fa5a105b1..31654e36f3 100644
--- a/actionpack/lib/action_controller/base/verification.rb
+++ b/actionpack/lib/action_controller/base/verification.rb
@@ -1,6 +1,6 @@
 module ActionController #:nodoc:
   module Verification #:nodoc:
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     # TODO : Remove the defined? check when new base is the main base
     if defined?(ActionController::Http)
diff --git a/actionpack/lib/action_controller/caching.rb b/actionpack/lib/action_controller/caching.rb
index 2f2eec10f6..38cf1da6a8 100644
--- a/actionpack/lib/action_controller/caching.rb
+++ b/actionpack/lib/action_controller/caching.rb
@@ -24,7 +24,7 @@ module ActionController #:nodoc:
   #   ActionController::Base.cache_store = :mem_cache_store, "localhost"
   #   ActionController::Base.cache_store = MyOwnStore.new("parameter")
   module Caching
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     autoload :Actions, 'action_controller/caching/actions'
     autoload :Fragments, 'action_controller/caching/fragments'
diff --git a/actionpack/lib/action_controller/new_base/compatibility.rb b/actionpack/lib/action_controller/new_base/compatibility.rb
index 1d0cb601e3..f278c2da14 100644
--- a/actionpack/lib/action_controller/new_base/compatibility.rb
+++ b/actionpack/lib/action_controller/new_base/compatibility.rb
@@ -1,6 +1,6 @@
 module ActionController
   module Rails2Compatibility
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     class ::ActionController::ActionControllerError < StandardError #:nodoc:
     end
diff --git a/actionpack/lib/action_controller/new_base/conditional_get.rb b/actionpack/lib/action_controller/new_base/conditional_get.rb
index 38f3d3cf68..8bd6db500b 100644
--- a/actionpack/lib/action_controller/new_base/conditional_get.rb
+++ b/actionpack/lib/action_controller/new_base/conditional_get.rb
@@ -1,6 +1,6 @@
 module ActionController
   module ConditionalGet
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     depends_on RackConvenience
 
diff --git a/actionpack/lib/action_controller/new_base/helpers.rb b/actionpack/lib/action_controller/new_base/helpers.rb
index 1dece13114..c2ebd343e3 100644
--- a/actionpack/lib/action_controller/new_base/helpers.rb
+++ b/actionpack/lib/action_controller/new_base/helpers.rb
@@ -4,7 +4,7 @@ require 'active_support/dependencies'
 
 module ActionController
   module Helpers
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     depends_on AbstractController::Helpers
 
diff --git a/actionpack/lib/action_controller/new_base/hide_actions.rb b/actionpack/lib/action_controller/new_base/hide_actions.rb
index 10b8b582f5..b45e520bee 100644
--- a/actionpack/lib/action_controller/new_base/hide_actions.rb
+++ b/actionpack/lib/action_controller/new_base/hide_actions.rb
@@ -1,6 +1,6 @@
 module ActionController
   module HideActions
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     included do
       extlib_inheritable_accessor :hidden_actions
diff --git a/actionpack/lib/action_controller/new_base/layouts.rb b/actionpack/lib/action_controller/new_base/layouts.rb
index 9b4057caaa..727358c394 100644
--- a/actionpack/lib/action_controller/new_base/layouts.rb
+++ b/actionpack/lib/action_controller/new_base/layouts.rb
@@ -1,6 +1,6 @@
 module ActionController
   module Layouts
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     depends_on ActionController::Renderer
     depends_on AbstractController::Layouts
diff --git a/actionpack/lib/action_controller/new_base/rack_convenience.rb b/actionpack/lib/action_controller/new_base/rack_convenience.rb
index e465acca6e..5dfa7d12f3 100644
--- a/actionpack/lib/action_controller/new_base/rack_convenience.rb
+++ b/actionpack/lib/action_controller/new_base/rack_convenience.rb
@@ -1,6 +1,6 @@
 module ActionController
   module RackConvenience
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     included do
       delegate :headers, :status=, :location=,
diff --git a/actionpack/lib/action_controller/new_base/render_options.rb b/actionpack/lib/action_controller/new_base/render_options.rb
index f12198a710..04b954134f 100644
--- a/actionpack/lib/action_controller/new_base/render_options.rb
+++ b/actionpack/lib/action_controller/new_base/render_options.rb
@@ -1,6 +1,6 @@
 module ActionController
   module RenderOptions
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     included do
       extlib_inheritable_accessor :_renderers
@@ -36,14 +36,12 @@ module ActionController
     end
   end
 
-  module RenderOption
-    extend ActiveSupport::DependencyModule
+  module RenderOption #:nodoc:
+    def self.extended(base)
+      base.extend ActiveSupport::Concern
+      base.depends_on ::ActionController::RenderOptions
 
-    included do
-      extend ActiveSupport::DependencyModule
-      depends_on ::ActionController::RenderOptions
-
-      def self.register_renderer(name)
+      def base.register_renderer(name)
         included { _add_render_option(name) }
       end
     end
@@ -51,7 +49,7 @@ module ActionController
 
   module Renderers
     module Json
-      include RenderOption
+      extend RenderOption
       register_renderer :json
 
       def _render_json(json, options)
@@ -63,7 +61,7 @@ module ActionController
     end
 
     module Js
-      include RenderOption
+      extend RenderOption
       register_renderer :js
 
       def _render_js(js, options)
@@ -73,7 +71,7 @@ module ActionController
     end
 
     module Xml
-      include RenderOption
+      extend RenderOption
       register_renderer :xml
 
       def _render_xml(xml, options)
@@ -82,8 +80,8 @@ module ActionController
       end
     end
 
-    module Rjs
-      include RenderOption
+    module RJS
+      extend RenderOption
       register_renderer :update
 
       def _render_update(proc, options)
@@ -94,14 +92,12 @@ module ActionController
     end
 
     module All
-      extend ActiveSupport::DependencyModule
+      extend ActiveSupport::Concern
 
-      included do
-        include ::ActionController::Renderers::Json
-        include ::ActionController::Renderers::Js
-        include ::ActionController::Renderers::Xml
-        include ::ActionController::Renderers::Rjs
-      end
+      depends_on ActionController::Renderers::Json
+      depends_on ActionController::Renderers::Js
+      depends_on ActionController::Renderers::Xml
+      depends_on ActionController::Renderers::RJS
     end
   end
 end
diff --git a/actionpack/lib/action_controller/new_base/renderer.rb b/actionpack/lib/action_controller/new_base/renderer.rb
index 737a0d6fcf..e132d4fdbb 100644
--- a/actionpack/lib/action_controller/new_base/renderer.rb
+++ b/actionpack/lib/action_controller/new_base/renderer.rb
@@ -1,6 +1,6 @@
 module ActionController
   module Renderer
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     depends_on AbstractController::Renderer
 
diff --git a/actionpack/lib/action_controller/new_base/rescuable.rb b/actionpack/lib/action_controller/new_base/rescuable.rb
index 4450a1131a..029e643d93 100644
--- a/actionpack/lib/action_controller/new_base/rescuable.rb
+++ b/actionpack/lib/action_controller/new_base/rescuable.rb
@@ -15,7 +15,7 @@ module ActionController #:nodoc:
   # behavior is achieved by overriding the <tt>rescue_action_in_public</tt>
   # and <tt>rescue_action_locally</tt> methods.
   module Rescue
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     included do
       include ActiveSupport::Rescuable
diff --git a/actionpack/lib/action_controller/new_base/session.rb b/actionpack/lib/action_controller/new_base/session.rb
index 9ee3e9e136..a585630230 100644
--- a/actionpack/lib/action_controller/new_base/session.rb
+++ b/actionpack/lib/action_controller/new_base/session.rb
@@ -1,6 +1,6 @@
 module ActionController
   module Session
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     depends_on RackConvenience
 
diff --git a/actionpack/lib/action_controller/new_base/testing.rb b/actionpack/lib/action_controller/new_base/testing.rb
index 97aadfe78f..e8d210d149 100644
--- a/actionpack/lib/action_controller/new_base/testing.rb
+++ b/actionpack/lib/action_controller/new_base/testing.rb
@@ -1,6 +1,6 @@
 module ActionController
   module Testing
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     depends_on RackConvenience
 
diff --git a/actionpack/lib/action_controller/new_base/url_for.rb b/actionpack/lib/action_controller/new_base/url_for.rb
index 87bc689134..902cac4d15 100644
--- a/actionpack/lib/action_controller/new_base/url_for.rb
+++ b/actionpack/lib/action_controller/new_base/url_for.rb
@@ -1,6 +1,6 @@
 module ActionController
   module UrlFor
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     depends_on RackConvenience
 
diff --git a/actionpack/lib/action_controller/testing/integration.rb b/actionpack/lib/action_controller/testing/integration.rb
index cc157816e2..af4ccb7837 100644
--- a/actionpack/lib/action_controller/testing/integration.rb
+++ b/actionpack/lib/action_controller/testing/integration.rb
@@ -301,7 +301,7 @@ module ActionController
     # A module used to extend ActionController::Base, so that integration tests
     # can capture the controller used to satisfy a request.
     module ControllerCapture #:nodoc:
-      extend ActiveSupport::DependencyModule
+      extend ActiveSupport::Concern
 
       included do
         alias_method_chain :initialize, :capture
diff --git a/actionpack/lib/action_view/render/partials.rb b/actionpack/lib/action_view/render/partials.rb
index f2429e8cef..eacf117bea 100644
--- a/actionpack/lib/action_view/render/partials.rb
+++ b/actionpack/lib/action_view/render/partials.rb
@@ -171,7 +171,7 @@ module ActionView
   #   <% end %>
   module Partials
     extend ActiveSupport::Memoizable
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
     
     included do
       attr_accessor :_partial      
diff --git a/activerecord/lib/active_record/aggregations.rb b/activerecord/lib/active_record/aggregations.rb
index 359e70f5ed..9ecf231a66 100644
--- a/activerecord/lib/active_record/aggregations.rb
+++ b/activerecord/lib/active_record/aggregations.rb
@@ -1,6 +1,6 @@
 module ActiveRecord
   module Aggregations # :nodoc:
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     def clear_aggregation_cache #:nodoc:
       self.class.reflect_on_all_aggregations.to_a.each do |assoc|
diff --git a/activerecord/lib/active_record/association_preload.rb b/activerecord/lib/active_record/association_preload.rb
index 5df76bb183..af80a579d6 100644
--- a/activerecord/lib/active_record/association_preload.rb
+++ b/activerecord/lib/active_record/association_preload.rb
@@ -1,7 +1,7 @@
 module ActiveRecord
   # See ActiveRecord::AssociationPreload::ClassMethods for documentation.
   module AssociationPreload #:nodoc:
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     # Implements the details of eager loading of ActiveRecord associations.
     # Application developers should not use this module directly.
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index 76726b7845..157716a477 100755
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -79,7 +79,7 @@ module ActiveRecord
 
   # See ActiveRecord::Associations::ClassMethods for documentation.
   module Associations # :nodoc:
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     # These classes will be loaded when associations are created.
     # So there is no need to eager load them.
diff --git a/activerecord/lib/active_record/attribute_methods.rb b/activerecord/lib/active_record/attribute_methods.rb
index d5e215af9d..15358979c2 100644
--- a/activerecord/lib/active_record/attribute_methods.rb
+++ b/activerecord/lib/active_record/attribute_methods.rb
@@ -2,7 +2,7 @@ require 'active_support/core_ext/enumerable'
 
 module ActiveRecord
   module AttributeMethods #:nodoc:
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     DEFAULT_SUFFIXES = %w(= ? _before_type_cast)
     ATTRIBUTE_TYPES_CACHED_BY_DEFAULT = [:datetime, :timestamp, :time, :date]
diff --git a/activerecord/lib/active_record/autosave_association.rb b/activerecord/lib/active_record/autosave_association.rb
index 4ab2818282..ef9c40ed4d 100644
--- a/activerecord/lib/active_record/autosave_association.rb
+++ b/activerecord/lib/active_record/autosave_association.rb
@@ -125,7 +125,7 @@ module ActiveRecord
   #   post.author.name = ''
   #   post.save(false) # => true
   module AutosaveAssociation
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     ASSOCIATION_TYPES = %w{ has_one belongs_to has_many has_and_belongs_to_many }
 
diff --git a/activerecord/lib/active_record/batches.rb b/activerecord/lib/active_record/batches.rb
index 4836601297..e41d38fb8f 100644
--- a/activerecord/lib/active_record/batches.rb
+++ b/activerecord/lib/active_record/batches.rb
@@ -1,6 +1,6 @@
 module ActiveRecord
   module Batches # :nodoc:
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     # When processing large numbers of records, it's often a good idea to do
     # so in batches to prevent memory ballooning.
diff --git a/activerecord/lib/active_record/calculations.rb b/activerecord/lib/active_record/calculations.rb
index 7afa7c49bd..727f4c1dc6 100644
--- a/activerecord/lib/active_record/calculations.rb
+++ b/activerecord/lib/active_record/calculations.rb
@@ -1,6 +1,6 @@
 module ActiveRecord
   module Calculations #:nodoc:
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     CALCULATIONS_OPTIONS = [:conditions, :joins, :order, :select, :group, :having, :distinct, :limit, :offset, :include, :from]
 
diff --git a/activerecord/lib/active_record/callbacks.rb b/activerecord/lib/active_record/callbacks.rb
index a77fdb1c13..36f5f2ce47 100644
--- a/activerecord/lib/active_record/callbacks.rb
+++ b/activerecord/lib/active_record/callbacks.rb
@@ -211,7 +211,7 @@ module ActiveRecord
   # needs to be aware of it because an ordinary +save+ will raise such exception
   # instead of quietly returning +false+.
   module Callbacks
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     CALLBACKS = %w(
       after_find after_initialize before_save after_save before_create after_create before_update after_update before_validation
diff --git a/activerecord/lib/active_record/dirty.rb b/activerecord/lib/active_record/dirty.rb
index ac84f6b209..178767e0c3 100644
--- a/activerecord/lib/active_record/dirty.rb
+++ b/activerecord/lib/active_record/dirty.rb
@@ -34,7 +34,7 @@ module ActiveRecord
   #   person.name << 'by'
   #   person.name_change    # => ['uncle bob', 'uncle bobby']
   module Dirty
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     DIRTY_SUFFIXES = ['_changed?', '_change', '_will_change!', '_was']
 
diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
index 721114d9d0..2b0cfc2c3b 100644
--- a/activerecord/lib/active_record/fixtures.rb
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -807,7 +807,7 @@ end
 
 module ActiveRecord
   module TestFixtures
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     included do
       setup :setup_fixtures
diff --git a/activerecord/lib/active_record/locking/optimistic.rb b/activerecord/lib/active_record/locking/optimistic.rb
index cf4f8864c6..cec5ca3324 100644
--- a/activerecord/lib/active_record/locking/optimistic.rb
+++ b/activerecord/lib/active_record/locking/optimistic.rb
@@ -42,7 +42,7 @@ module ActiveRecord
     # To override the name of the lock_version column, invoke the <tt>set_locking_column</tt> method.
     # This method uses the same syntax as <tt>set_table_name</tt>
     module Optimistic
-      extend ActiveSupport::DependencyModule
+      extend ActiveSupport::Concern
 
       included do
         cattr_accessor :lock_optimistically, :instance_writer => false
diff --git a/activerecord/lib/active_record/named_scope.rb b/activerecord/lib/active_record/named_scope.rb
index e7151a3d47..1b22fa5e24 100644
--- a/activerecord/lib/active_record/named_scope.rb
+++ b/activerecord/lib/active_record/named_scope.rb
@@ -3,7 +3,7 @@ require 'active_support/core_ext/hash/except'
 
 module ActiveRecord
   module NamedScope
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     # All subclasses of ActiveRecord::Base have one named scope:
     # * <tt>scoped</tt> - which allows for the creation of anonymous \scopes, on the fly: <tt>Shirt.scoped(:conditions => {:color => 'red'}).scoped(:include => :washing_instructions)</tt>
diff --git a/activerecord/lib/active_record/nested_attributes.rb b/activerecord/lib/active_record/nested_attributes.rb
index c532d3dfa3..0beb4321a2 100644
--- a/activerecord/lib/active_record/nested_attributes.rb
+++ b/activerecord/lib/active_record/nested_attributes.rb
@@ -3,7 +3,7 @@ require 'active_support/core_ext/object/try'
 
 module ActiveRecord
   module NestedAttributes #:nodoc:
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     included do
       class_inheritable_accessor :reject_new_nested_attributes_procs, :instance_writer => false
diff --git a/activerecord/lib/active_record/observer.rb b/activerecord/lib/active_record/observer.rb
index 1ca76c7b2f..89ec0962bf 100644
--- a/activerecord/lib/active_record/observer.rb
+++ b/activerecord/lib/active_record/observer.rb
@@ -3,7 +3,7 @@ require 'set'
 
 module ActiveRecord
   module Observing # :nodoc:
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     module ClassMethods
       # Activates the observers assigned. Examples:
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index 3747ba449d..0baa9654b7 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -1,6 +1,6 @@
 module ActiveRecord
   module Reflection # :nodoc:
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     # Reflection allows you to interrogate Active Record classes and objects about their associations and aggregations.
     # This information can, for example, be used in a form builder that took an Active Record object and created input
diff --git a/activerecord/lib/active_record/serializers/json_serializer.rb b/activerecord/lib/active_record/serializers/json_serializer.rb
index d376fd5e1b..67e2b2abb3 100644
--- a/activerecord/lib/active_record/serializers/json_serializer.rb
+++ b/activerecord/lib/active_record/serializers/json_serializer.rb
@@ -2,7 +2,7 @@ require 'active_support/json'
 
 module ActiveRecord #:nodoc:
   module Serialization
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     included do
       cattr_accessor :include_root_in_json, :instance_writer => false
diff --git a/activerecord/lib/active_record/timestamp.rb b/activerecord/lib/active_record/timestamp.rb
index 3734e170af..da075dabd3 100644
--- a/activerecord/lib/active_record/timestamp.rb
+++ b/activerecord/lib/active_record/timestamp.rb
@@ -8,7 +8,7 @@ module ActiveRecord
   # Timestamps are in the local timezone by default but you can use UTC by setting
   #   <tt>ActiveRecord::Base.default_timezone = :utc</tt>
   module Timestamp
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     included do
       alias_method_chain :create, :timestamps
diff --git a/activerecord/lib/active_record/transactions.rb b/activerecord/lib/active_record/transactions.rb
index 471a81dfb5..4f8ccdd40e 100644
--- a/activerecord/lib/active_record/transactions.rb
+++ b/activerecord/lib/active_record/transactions.rb
@@ -3,7 +3,7 @@ require 'thread'
 module ActiveRecord
   # See ActiveRecord::Transactions::ClassMethods for documentation.
   module Transactions
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     class TransactionError < ActiveRecordError # :nodoc:
     end
diff --git a/activerecord/lib/active_record/validations.rb b/activerecord/lib/active_record/validations.rb
index a18fb3f426..efc59908cf 100644
--- a/activerecord/lib/active_record/validations.rb
+++ b/activerecord/lib/active_record/validations.rb
@@ -302,7 +302,7 @@ module ActiveRecord
   #
   # An Errors object is automatically created for every Active Record.
   module Validations
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     VALIDATIONS = %w( validate validate_on_create validate_on_update )
 
diff --git a/activerecord/test/cases/associations/eager_load_nested_include_test.rb b/activerecord/test/cases/associations/eager_load_nested_include_test.rb
index cb7fe9698b..f313a75233 100644
--- a/activerecord/test/cases/associations/eager_load_nested_include_test.rb
+++ b/activerecord/test/cases/associations/eager_load_nested_include_test.rb
@@ -7,7 +7,7 @@ require 'models/categorization'
 require 'active_support/core_ext/array/random_access'
 
 module Remembered
-  extend ActiveSupport::DependencyModule
+  extend ActiveSupport::Concern
 
   included do
     after_create :remember
diff --git a/activerecord/test/cases/repair_helper.rb b/activerecord/test/cases/repair_helper.rb
index 686bfee46d..80d04010d6 100644
--- a/activerecord/test/cases/repair_helper.rb
+++ b/activerecord/test/cases/repair_helper.rb
@@ -1,7 +1,7 @@
 module ActiveRecord
   module Testing
     module RepairHelper
-      extend ActiveSupport::DependencyModule
+      extend ActiveSupport::Concern
 
       module Toolbox
         def self.record_validations(*model_classes)
diff --git a/activesupport/lib/active_support/autoload.rb b/activesupport/lib/active_support/autoload.rb
index ed229d1c5f..75706855d6 100644
--- a/activesupport/lib/active_support/autoload.rb
+++ b/activesupport/lib/active_support/autoload.rb
@@ -5,7 +5,7 @@ module ActiveSupport
   autoload :BufferedLogger, 'active_support/buffered_logger'
   autoload :Cache, 'active_support/cache'
   autoload :Callbacks, 'active_support/callbacks'
-  autoload :NewCallbacks, 'active_support/new_callbacks'
+  autoload :Concern, 'active_support/concern'
   autoload :ConcurrentHash, 'active_support/concurrent_hash'
   autoload :DependencyModule, 'active_support/dependency_module'
   autoload :Deprecation, 'active_support/deprecation'
@@ -15,6 +15,7 @@ module ActiveSupport
   autoload :MessageEncryptor, 'active_support/message_encryptor'
   autoload :MessageVerifier, 'active_support/message_verifier'
   autoload :Multibyte, 'active_support/multibyte'
+  autoload :NewCallbacks, 'active_support/new_callbacks'
   autoload :OptionMerger, 'active_support/option_merger'
   autoload :OrderedHash, 'active_support/ordered_hash'
   autoload :OrderedOptions, 'active_support/ordered_options'
diff --git a/activesupport/lib/active_support/concern.rb b/activesupport/lib/active_support/concern.rb
new file mode 100644
index 0000000000..154f8807f7
--- /dev/null
+++ b/activesupport/lib/active_support/concern.rb
@@ -0,0 +1,22 @@
+require 'active_support/dependency_module'
+
+module ActiveSupport
+  module Concern
+    include DependencyModule
+
+    def append_features(base)
+      if super
+        base.extend const_get("ClassMethods") if const_defined?("ClassMethods")
+        base.class_eval(&@_included_block) if instance_variable_defined?("@_included_block")
+      end
+    end
+
+    def included(base = nil, &block)
+      if base.nil?
+        @_included_block = block
+      else
+        super
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/dependency_module.rb b/activesupport/lib/active_support/dependency_module.rb
index 9872b9654b..6847c0f86a 100644
--- a/activesupport/lib/active_support/dependency_module.rb
+++ b/activesupport/lib/active_support/dependency_module.rb
@@ -1,19 +1,9 @@
 module ActiveSupport
   module DependencyModule
     def append_features(base)
-      return if base < self
+      return false if base < self
       (@_dependencies ||= []).each { |dep| base.send(:include, dep) }
       super
-      base.extend const_get("ClassMethods") if const_defined?("ClassMethods")
-      base.class_eval(&@_included_block) if instance_variable_defined?("@_included_block")
-    end
-
-    def included(base = nil, &block)
-      if base.nil?
-        @_included_block = block
-      else
-        super
-      end
     end
 
     def depends_on(*mods)
diff --git a/activesupport/test/dependency_module_test.rb b/activesupport/test/concern_test.rb
similarity index 63%
rename from activesupport/test/dependency_module_test.rb
rename to activesupport/test/concern_test.rb
index be7db0fa7b..22f7ec2064 100644
--- a/activesupport/test/dependency_module_test.rb
+++ b/activesupport/test/concern_test.rb
@@ -1,9 +1,9 @@
 require 'abstract_unit'
-require 'active_support/dependency_module'
+require 'active_support/concern'
 
-class DependencyModuleTest < Test::Unit::TestCase
+class ConcernTest < Test::Unit::TestCase
   module Baz
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     module ClassMethods
       def baz
@@ -29,7 +29,7 @@ class DependencyModuleTest < Test::Unit::TestCase
   end
 
   module Bar
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     depends_on Baz
 
@@ -43,7 +43,7 @@ class DependencyModuleTest < Test::Unit::TestCase
   end
 
   module Foo
-    extend ActiveSupport::DependencyModule
+    extend ActiveSupport::Concern
 
     depends_on Bar, Baz
   end
@@ -55,17 +55,17 @@ class DependencyModuleTest < Test::Unit::TestCase
   def test_module_is_included_normally
     @klass.send(:include, Baz)
     assert_equal "baz", @klass.new.baz
-    assert_equal DependencyModuleTest::Baz, @klass.included_modules[0]
+    assert_equal ConcernTest::Baz, @klass.included_modules[0]
 
     @klass.send(:include, Baz)
     assert_equal "baz", @klass.new.baz
-    assert_equal DependencyModuleTest::Baz, @klass.included_modules[0]
+    assert_equal ConcernTest::Baz, @klass.included_modules[0]
   end
 
   def test_class_methods_are_extended
     @klass.send(:include, Baz)
     assert_equal "baz", @klass.baz
-    assert_equal DependencyModuleTest::Baz::ClassMethods, (class << @klass; self.included_modules; end)[0]
+    assert_equal ConcernTest::Baz::ClassMethods, (class << @klass; self.included_modules; end)[0]
   end
 
   def test_included_block_is_ran
@@ -78,11 +78,11 @@ class DependencyModuleTest < Test::Unit::TestCase
     assert_equal "bar", @klass.new.bar
     assert_equal "bar+baz", @klass.new.baz
     assert_equal "baz", @klass.baz
-    assert_equal [DependencyModuleTest::Bar, DependencyModuleTest::Baz], @klass.included_modules[0..1]
+    assert_equal [ConcernTest::Bar, ConcernTest::Baz], @klass.included_modules[0..1]
   end
 
   def test_depends_on_with_multiple_modules
     @klass.send(:include, Foo)
-    assert_equal [DependencyModuleTest::Foo, DependencyModuleTest::Bar, DependencyModuleTest::Baz], @klass.included_modules[0..2]
+    assert_equal [ConcernTest::Foo, ConcernTest::Bar, ConcernTest::Baz], @klass.included_modules[0..2]
   end
 end