title: Inheritance from non-protocol, non-class type 'CGPoint'
body: <p>I want to create a custom CGPoint subclass to add some proprieties, but I get this error:</p>
  
  <blockquote>
    <p>Inheritance from non-protocol, non-class type 'CGPoint'</p>
  </blockquote>
  
  <p>I have no idea why this is not possible. My class is as simple as this:</p>
  
  <pre><code>import UIKit
  
  class IYAttachPoint: CGPoint {
  
    var holder: String = "No holder"
    var unavailable: Bool = false
  
  }
  </code></pre>
  
  <p>I've tried adding some libraries like CoreGraphics or QuartzCore without success. If there are already some questions or solutions to this problem, please point me in the right direction.</p>