title: Can't pass Date to NSPredicate(format: ...) without "as CVarArg"
body: <p>Is this how I'm supposed to pass a <code>Date</code> to <code>NSPredicate.init(format predicateFormat: String, arguments argList: CVaListPointer)</code>.</p>
  
  <pre><code>let endDate = Date()
  NSPredicate(format: "endDate == %@", endDate as CVarArg)
  </code></pre>
  
  <p>It looks kinda clumsy, and I suspect I'm doing something wrong.</p>