class Rails::DeprecatedConstant

def method_missing(meth, *args, &block)
  ::ActiveSupport::Deprecation.warn("#{@old} is deprecated. Please use #{@new}") unless @warned
  @warned = true
  target = @target.call
  if target.respond_to?(meth)
    target.send(meth, *args, &block)
  else
    super
  end
end