Подкласса URLSession IOS 10

Question

Я пытаюсь подкласс URLSession на прошивке 10 с помощью Xcode 8. Я считаю, что Swift система типа путается, но может быть что-то не хватаю:

class MyURLSession: URLSession { 

// No errors 
override func downloadTask(with request: URLRequest) -> URLSessionDownloadTask { 
    return URLSessionDownloadTask() 
} 

// No errors 
override func downloadTask(with url: URL) -> URLSessionDownloadTask { 
    return URLSessionDownloadTask() 
} 

// See errors below 
override func downloadTask(with request: URLRequest, completionHandler: @escaping (URL?, URLResponse?, Error?) -> Void) -> URLSessionDownloadTask { 
    return URLSessionDownloadTask() 
} 

// See errors below 
override func downloadTask(with url: URL, completionHandler: @escaping (URL?, URLResponse?, Error?) -> Void) -> URLSessionDownloadTask { 
    return URLSessionDownloadTask() 
} 
} 



error: method does not override any method from its superclass 
    override func downloadTask(with request: URLRequest, completionHandler: @escaping (URL?, URLResponse?, Error?) -> Void) -> URLSessionDownloadTask { 
       ^
Foundation.URLSession:6:15: note: potential overridden instance method 'downloadTask(with:completionHandler:)' here 
    open func downloadTask(with request: URLRequest, completionHandler: @escaping (URL?, URLResponse?, Error?) -> Swift.Void) -> URLSessionDownloadTask 
      ^
Foundation.URLSession:7:15: note: potential overridden instance method 'downloadTask(with:completionHandler:)' here 
    open func downloadTask(with url: URL, completionHandler: @escaping (URL?, URLResponse?, Error?) -> Swift.Void) -> URLSessionDownloadTask 
      ^
/Users/pshah/Networking/Webservice.swift:108:19: error: method does not override any method from its superclass 
    override func downloadTask(with url: URL, completionHandler: @escaping (URL?, URLResponse?, Error?) -> Void) -> URLSessionDownloadTask { 
       ^
Foundation.URLSession:6:15: note: potential overridden instance method 'downloadTask(with:completionHandler:)' here 
    open func downloadTask(with request: URLRequest, completionHandler: @escaping (URL?, URLResponse?, Error?) -> Swift.Void) -> URLSessionDownloadTask 
      ^
Foundation.URLSession:7:15: note: potential overridden instance method 'downloadTask(with:completionHandler:)' here 
    open func downloadTask(with url: URL, completionHandler: @escaping (URL?, URLResponse?, Error?) -> Swift.Void) -> URLSessionDownloadTask 
      ^

Answer 1

Я понял это. У меня есть Error в моем проекте, поэтому он должен был квалифицировать Error? как Swift.Error? в методах с ошибками.