title: Is Rails 3.1 Edge breaking XmlMarkup::Builder?
body: <p>There are a number of examples on the Web (such as <a href="http://techoctave.com/c7/posts/32-create-an-rss-feed-in-rails" rel="nofollow">http://techoctave.com/c7/posts/32-create-an-rss-feed-in-rails</a>) showing how to make a nice RSS feed using Builder. The canonical template is something like this:</p>
  
  <pre><code>xml.instruct! :xml, :version =&gt; "1.0" 
  xml.rss :version =&gt; "2.0" do
  xml.channel do
    xml.title "Your Blog Title"
    xml.description "A blog about software and chocolate"
    xml.link posts_url
  
    for post in @posts
      xml.item do
        xml.title post.title
        xml.description post.content
        xml.pubDate post.posted_at.to_s(:rfc822)
        xml.link post_url(post)
        xml.guid post_url(post)
      end
    end
  end
  </code></pre>
  
  <p>This works fine in Rails 3.0.7. In Rails 3.1 Edge, every command seems to produce...</p>
  
  <pre><code>Rendered home/index.rss.builder (25.2ms)
  Completed 500 Internal Server Error in 875ms
  
  ActionView::Template::Error (wrong number of arguments (1 for 0)):
  1: xml.instruct!(:xml, :encoding =&gt; "UTF-8")
  2: 
  3: xml.rss :version =&gt; "2.0" do
  4:   xml.channel do
  app/views/home/index.rss.builder:1:in   `_app_views_home_index_rss_builder___2123990471_2215695900'
  app/controllers/home_controller.rb:17:in `index'
  app/controllers/home_controller.rb:11:in `index'
  </code></pre>