可选类型的值必须解包以引用成员，但对于隐式解包的可选属性

Question

为什么我会收到这个？它是一个隐式展开的可选属性。我不认为我应该得到这个错误。我尝试清理我的构建文件夹并删除派生数据，然后关闭 Xcode。没有任何效果。

var questionsWrap: QuestionsWrapper
    
func userMadeSelection(
    _ responseId: Int,
    _ myTheir: Question.Response.Selections.MyTheir,
    _ choice: Question.Response.Selections.MyTheir.Choice
) {
    guard let id = question.id else { return }
    questionsWrap.saveSelection(
        questionId: id,
        responseID: responseId,
        myTheir: myTheir,
       choice: choice
    ) { success in
        if !success {
           AlertViewController<Any>.alertFailure(
               message:  "We made a mistake and we weren't able to save your selection."
            )
        }
    }
    singleQuestionDataSource.observableQuestion.value = question
    print(#line, "userMadeSelectionImportance: \(responseId) \(myTheir) \(choice)")
    if choice.changedBetweenPolarAndNeutral(
        with: questionsWrap.question.theirInteractionStyle
        ) {
        let presenter = Question.Importance.Presenter(question)
        update(presenter?.importance)
        questionCell?.importancePresenter = presenter
    }
}

方法定义

func saveSelection(
    questionId: Int,
    responseID: Int,
    myTheir: Question.Response.Selections.MyTheir,
    choice: Question.Response.Selections.MyTheir.Choice,
    context: Context,
    successAction: SuccessAction? = nil
) {
        
        guard let questionIndex = questions.index(of: questionId),
            let responseIndex = questions[questionIndex].responses.index(of: responseID) else {
                successAction?(false)
                return
        }
        
        questions[questionIndex].responses[responseIndex].set(myTheir, choice, for: context)
        let response = questions[questionIndex].responses[responseIndex]
        URL.make(
           my: response.choice(for: .my, UserDefaults.questionContext),
           their: response.choice(for: .their, UserDefaults.questionContext),
           forResponseID: responseID,
           forQuestionID: questionId,
           forContext: UserDefaults.questionContext
           ).get { jsonDict in
            successAction?(jsonDict.success)
        }
    }

不幸的是，我不知道要提供什么代码来自动重现这个问题。

我正在超越常规并发布屏幕截图以证明错误正在显示。

Answer 1

看到带有隐式解包 Optional 的错误消息的通常原因是隐式解包不会通过赋值传播自身。例如，这是合法的：

    var s : String!
    print(s.count)

但这不是：

    let s2 = s
    print(s2.count) // value must be unwrapped

Answer 2

我想通了，我更改了 saveSelection 的方法签名以需要另一个参数，但我忘记添加默认值或在调用中添加参数。我不知道为什么编译器不告诉我，而是...

可选类型的值必须解包以引用成员，但对于隐式解包的可选属性

Value of optional type must be unwrapped to refer to member, BUT its for an implicitly unwrapped optional property

optional

swift

可选类型的值必须解包以引用成员，但对于隐式解包的可选 属性

Value of optional type must be unwrapped to refer to member, BUT its for an implicitly unwrapped optional property

optional

swift

可选类型的值必须解包以引用成员，但对于隐式解包的可选属性