title: Type "myViewController" does not conform to protocol UIPIckerDataSource in Swift
body: <p>I just create a new class in Swift, it's called <code>myViewController</code> and it's a <code>UIViewController</code>. 
  Now I'm trying to make it a UIPickerViewDelegate and DataSource but <em>i got a strange error</em></p>
  
  <pre><code>import UIKit
  
  class myViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
     ...
  }
  </code></pre>
  
  <p>It says <code>Type "myViewController" does not conform to protocol UIPIckerDataSource</code> over the UIPickerViewDataSource. </p>
  
  <p><strong>Is it a bug of Xcode-Beta 3??</strong></p>
  
  <p><a href="https://i.stack.imgur.com/MUVhC.png" rel="noreferrer"><img src="https://i.stack.imgur.com/MUVhC.png" alt="Screenshot for compile-time error"></a></p>