title: Guard with where in Swift 3
body: <p>In Swift 2, we can easy add where to a guard statment</p>
  
  <pre><code>guard let varA = 1 where varB == 2 else {return}
  </code></pre>
  
  <p>But the <code>where</code> removed in swift 3, how can I do like that in Swift 3 ?</p>