module ActiveSupport::JSON::Encoding

def const_missing(name)
  if name == :CircularReferenceError
    message = "The JSON encoder in Rails 4.1 no longer offers protection from circular references. " \
              "You are seeing this warning because you are rescuing from (or otherwise referencing) " \
              "ActiveSupport::Encoding::CircularReferenceError. In the future, this error will be " \
              "removed from Rails. You should remove these rescue blocks from your code and ensure " \
              "that your data structures are free of circular references so they can be properly " \
              "serialized into JSON.\n\n" \
              "For example, the following Hash contains a circular reference to itself:\n" \
              "   h = {}\n" \
              "   h['circular'] = h\n" \
              "In this case, calling h.to_json would not work properly."
    ActiveSupport::Deprecation.warn message
    SystemStackError
  else
    super
  end
end