ios - xcode 6 beta 4 - MessageComposeResult 不可转换为 OptionalNilComparisonType

Question

我刚刚从 Xcode 6 Beta 3 升级到 Beta 4。在 3 中，我的应用程序编译完美，但在 4 中出现以下错误。请任何人解释并提供解决方案。

func messageComposeViewController(sendMsg: MFMessageComposeViewController, didFinishWithResult result: MessageComposeResult) {

    switch result {

    case MessageComposeResultSent :    //Error: MessageComposeResult is not convertible to _OptionalNilComparisonType
        label2.text = "Msg Sent"

    case MessageComposeResultCancelled : //Error: MessageComposeResult is not convertible to _OptionalNilComparisonType
        label2.text = "Msg Send Cancelled"

    case MessageComposeResultFailed :   //Error: MessageComposeResult is not convertible to _OptionalNilComparisonType
        label2.text = "Msg Send Failed"

    default:
        label2.text = "Msg Error"

    }

    self.dismissViewControllerAnimated(true, completion: nil)
    self.reloadInputViews()

}

Answer 1

func messageComposeViewController(controller: MFMessageComposeViewController!, didFinishWithResult result: MessageComposeResult) {

    switch result.value {

    case MessageComposeResultSent.value :
        println("enviado")

    case MessageComposeResultCancelled.value :
        println("cancelado")

    case MessageComposeResultFailed.value :
        println("fallo")

    default:
        println("")

    }

}