title: ArgumentError (too few arguments): when calling format.json on rails 4.04
body: <p>When executing</p>
  
  <pre><code>format.json{render json: {}, status: :ok}
  </code></pre>
  
  <p>in Rails 4.0.4, I get the following error:</p>
  
  <pre><code>ArgumentError (too few arguments):
  </code></pre>
  
  <p>Although I have another program (with Rails 3.2.13) where the exact same line executes with no problem. am I missing something here?</p>
  
  <p>any gems?</p>
  
  <p>or change in syntax with rails 4?</p>