Hi, the first code is the guided code. the second code is with strong referencing; i removed [weak ac, weak self]. The app works with both codes so I wonder whats the problem with strong reference cycling?

Guided code:

@objc func promptForAnswer(){
        let ac = UIAlertController(title: "Enter answer", message: nil, preferredStyle: .alert)
        ac.addTextField(configurationHandler: nil)

        let submitAction = UIAlertAction(title: "Submit", style: .default) {
            [weak self, weak ac] action in 
            guard let answer = ac?.textFields?[0].text else { return }
            self?.submit(answer)

        }
        ac.addAction(submitAction)
        present(ac, animated: true, completion: nil)
    }

After removing weak capture lists:

@objc func promptForAnswer(){
        let ac = UIAlertController(title: "Enter answer", message: nil, preferredStyle: .alert)
        ac.addTextField(configurationHandler: nil)

        let submitAction = UIAlertAction(title: "Submit", style: .default) {
             _ in 
            guard let answer = ac.textFields?[0].text else { return }
            self.submit(answer)

        }
        ac.addAction(submitAction)
        present(ac, animated: true, completion: nil)
    }