3 files changed, 21 insertions, 2 deletions
diff --git a/activesupport/lib/active_support/concern.rb b/activesupport/lib/active_support/concern.rb
index b796d01dfd..9d5cee54e3 100644
--- a/activesupport/lib/active_support/concern.rb
+++ b/activesupport/lib/active_support/concern.rb
@@ -26,7 +26,7 @@ module ActiveSupport
   #       scope :disabled, -> { where(disabled: true) }
   #     end
   #
-  #     module ClassMethods
+  #     class_methods do
   #       ...
   #     end
   #   end
@@ -130,5 +130,13 @@ module ActiveSupport
         super
       end
     end
+
+    def class_methods(&class_methods_module_definition)
+      mod = const_defined?(:ClassMethods) ?
+        const_get(:ClassMethods) :
+        const_set(:ClassMethods, Module.new)
+
+      mod.module_eval(&class_methods_module_definition)
+    end
   end
 end
diff --git a/activesupport/lib/active_support/core_ext/kernel.rb b/activesupport/lib/active_support/core_ext/kernel.rb
index 0275f4c037..aa19aed43b 100644
--- a/activesupport/lib/active_support/core_ext/kernel.rb
+++ b/activesupport/lib/active_support/core_ext/kernel.rb
@@ -1,4 +1,5 @@
-require 'active_support/core_ext/kernel/reporting'
 require 'active_support/core_ext/kernel/agnostics'
+require 'active_support/core_ext/kernel/concern'
 require 'active_support/core_ext/kernel/debugger'
+require 'active_support/core_ext/kernel/reporting'
 require 'active_support/core_ext/kernel/singleton_class'
diff --git a/activesupport/lib/active_support/core_ext/kernel/concern.rb b/activesupport/lib/active_support/core_ext/kernel/concern.rb
new file mode 100644
index 0000000000..c200a78d36
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/kernel/concern.rb
@@ -0,0 +1,10 @@
+require 'active_support/core_ext/module/concerning'
+
+module Kernel
+  # A shortcut to define a toplevel concern, not within a module.
+  #
+  # See ActiveSupport::CoreExt::Module::Concerning for more.
+  def concern(topic, &module_definition)
+    Object.concern topic, &module_definition
+  end
+end