Inheritance from non-protocol, non-class type 'CGPoint'

Question

I want to create a custom CGPoint subclass to add some proprieties, but I get this error:

Inheritance from non-protocol, non-class type 'CGPoint'

I have no idea why this is not possible. My class is as simple as this:

import UIKit

class IYAttachPoint: CGPoint {

  var holder: String = "No holder"
  var unavailable: Bool = false

}

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.

Answer 1

This is not possible because you want to inherit a struct from a class. CGPoint is a struct and therefore it does not support inheritance, although it can conform to protocols.

If you really want to do this, use composition instead of inheritance.

class IYAttachPoint {

  var point:CGPoint?
  var holder: String = "No holder"
  var unavailable: Bool = false
}