title: Swift 2.0 Subclassing a subclass of UIViewController and called convenience initializers
body: <p>Have a bit of confusion regarding designated and convenience initializers for UIViewController in Swift 2.0/Xcode 7beta3. Our UIViewControllers are all defined in code, there are no Nibs</p>
  
  <p>Currently class A inherits from UIViewController like this</p>
  
  <pre><code>class A : UIViewController {
      convenience init() {
          ...
          self.init(nibName:nil, bundle:nil)
          ...
      }    
  }
  </code></pre>
  
  <p>Then class B inherits from class A and should override the convenience init and call its as super.init()</p>
  
  <pre><code>class B : A {
      convenience init() {
          super.init()
          ...
      }    
  }
  </code></pre>
  
  <p>The compiler does not allow this with <em>Must call a designated initializer of the superclass '...'</em> error on <code>super.init()</code></p>