title: Contextual type 'NSFastEnumeration' cannot be used with array literal
body: <p>Swift 3, would you do this?</p>
  
  <pre><code>let changeRequest = PHAssetCollectionChangeRequest(...)
  let fastEnumeration = NSArray(array: [PHObjectPlaceholder])
  albumChangeRequest?.addAssets(fastEnumeration)
  </code></pre>
  
  <p>or this?</p>
  
  <pre><code>let changeRequest = PHAssetCollectionChangeRequest(...)
  albumChangeRequest?.addAssets([PHObjectPlaceholder] as NSFastEnumeration)
  </code></pre>
  
  <p>and what is the difference?</p>