title: Casting array of objects to array of subclassed objects in Swift
body: <p>I have an array of EKReminder, like so:</p>
  
  <pre><code>var currentReminders: [EKReminder]? = ....
  </code></pre>
  
  <p>I want to cast this array to an array of subclasses of EKReminder. Let's say this is the subclass:</p>
  
  <pre><code>import Foundation
  import EventKit
  
  class NNReminder: EKReminder {
      var additionalNotes: String?
  }
  </code></pre>
  
  <p>How would I cast currentReminders to [NNReminder]? I tried several ways but they all failed.</p>