Why can the keyword “weak” only be applied to class and class-bound protocol types

Question

When I\'m declaring variables as weak in Swift, I sometimes get the error message from Xcode:

\'weak\' may only be applied to class and

Answer 1

I find out in one case where you even have class type but still you get this error message.

For example,

class MyVC: UIViewController {
   var myText: UITextView = {
      [weak self]
      let text = UITextView()
      // some codes using self
      return text
   }()
}

Here an UITextView object is returned from an anonymous block as initialization of var myText. I got the same type of error message. To resolve the issue, the var has to be marked as lazy:

class MyVC: UIViewController {
   lasy var myText: UITextView = {
      [weak self]
      let text = UITextView()
      // some codes using self
      return text
   }()
}