3.1: params_wrapper raises error on anynomous controllers

Given this code:

controller = Class.new(ApplicationController) do
  # ...
end

I get the following error:

+/Users/david/.rvm/gems/ruby-1.9.2-p180@rspec-dev/gems/activesupport-3.1.0.beta1/lib/active_support/whiny_nil.rb:48:in `method_missing': undefined method `sub' for nil:NilClass (NoMethodError)
+   from /Users/david/.rvm/gems/ruby-1.9.2-p180@rspec-dev/gems/actionpack-3.1.0.beta1/lib/action_controller/metal/params_wrapper.rb:140:in `_default_wrap_model'

This is caused by model_name = self.name.sub(/Controller$/, '').singularize on https://github.com/rails/rails/blob/8b0262f9535cb9ad2215e5ed672150e...