Rails 3.0b3 and 3.0b4: :as option in resource router fails

In Rails 2.3.5,

1. create an app
2. ./script/generate scaffold Post title:string body:string
3. In routes.rb, add :as => :widgets to map.resources :posts
4. http://localhost:3000/widgets shows your resource

In Rails 3.0b4 (and b3),

1. create an app
2. rails g scaffold Post title:string body:string
3. In routes.rb, add :as => :widgets to map.resources :posts
4. http://localhost:3000/widgets throws a RoutingError