2 files changed, 18 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/json/encoding.rb b/activesupport/lib/active_support/json/encoding.rb
index 389df58ec4..1a95bd63e6 100644
--- a/activesupport/lib/active_support/json/encoding.rb
+++ b/activesupport/lib/active_support/json/encoding.rb
@@ -1,5 +1,6 @@
 require 'active_support/core_ext/object/to_json'
 require 'active_support/core_ext/module/delegation'
+require 'active_support/json/variable'
 
 require 'bigdecimal'
 require 'active_support/core_ext/big_decimal/conversions' # for #to_s
diff --git a/activesupport/lib/active_support/json/variable.rb b/activesupport/lib/active_support/json/variable.rb
new file mode 100644
index 0000000000..8af661a795
--- /dev/null
+++ b/activesupport/lib/active_support/json/variable.rb
@@ -0,0 +1,17 @@
+require 'active_support/deprecation'
+
+module ActiveSupport
+  module JSON
+    # Deprecated: A string that returns itself as its JSON-encoded form.
+    class Variable < String
+      def initialize(*args)
+        ActiveSupport::Deprecation.warn 'ActiveSupport::JSON::Variable is deprecated and will be removed in Rails 4.1. ' \
+                                        'For your own custom JSON literals, define #as_json and #encode_json yourself.'
+        super
+      end
+
+      def as_json(options = nil) self end #:nodoc:
+      def encode_json(encoder) self end #:nodoc:
+    end
+  end
+end