无法分配给 'localVc' 的 属性 这是一个只获取对象？

Question

就像下面显示的代码，为什么swift 不允许分配只读对象的属性？只读对象 'localVc' 具有设置写入 属性“refreshGesture”。

public protocol HVSHomeVideoChildProtocol {
    var refreshGesture: UIPanGestureRecognizer! {get set}
}

class HVSHomeLocalVideoController: HVSHomeVideoChildProtocol {

    public var refreshGesture: UIPanGestureRecognizer!
}


typealias HVSHomeVideoController = (UIViewController & HVSHomeVideoChildProtocol)

@objc(HSAVideoHomeViewController)
class HSAVideoHomeViewController: UIViewController {
    
    var refreshGesture: UIPanGestureRecognizer!
    let singleLocalVc = HVSHomeLocalVideoController.init()  
    var localVc: HVSHomeVideoController {
        return singleLocalVc
    }


    public override func viewDidLoad() {
        super.viewDidLoad()
        refreshGesture = UIPanGestureRecognizer.init(target: self, action: #selector(refreshGestureAction(sender:)))
        localVc.refreshGesture = refreshGesture
    }

}

Answer 1

改变

public protocol HVSHomeVideoChildProtocol {
    var refreshGesture: UIPanGestureRecognizer! {get set}
}

至

public protocol HVSHomeVideoChildProtocol : AnyObject {
    var refreshGesture: UIPanGestureRecognizer! {get set}
}