title: Type HalfOpenInterval<T> does not conform to protocol BooleanType
body: <p>I have a very simple for loop that is giving me troubles. This code ran without issue in Xcode beta 4, but in beta 5 it is complaining that the half open interval (and the closed interval) don't conform to BooleanType. What has changed, why doesn't this work anymore, or is this a bug?</p>
  
  <pre><code>for let i = 0; i..&lt;cellCount!; ++i {
      //do stuff
  }
  </code></pre>
  
  <p><code>cellCount</code> is defined as an optional <code>Int</code> property:</p>
  
  <pre><code>private var cellCount: Int?
  </code></pre>
  
  <p>I have tried storing the cellCount into a non-optional constant but the issue still remains:</p>
  
  <pre><code>let numberOfCells: Int = cellCount!
  for let i = 0; i..&lt;numberOfCells; ++i {
      //do stuff
  }
  </code></pre>
  
  <p>I see in the Release Notes a lot has changed with Ranges, but nothing seems to be relevant to this issue.</p>