Swift 4.1 表达式类型在没有上下文的情况下不明确

Question

我已经尝试了一些来自其他具有类似问题的堆栈溢出问题的建议，但它们没有用。我的问题只发生在我从 Xcode 9.2 更新到最新的 Xcode 9.3 时。

这行代码给了我:

"Type of expression is ambiguous without more context"

data = try container.decodeIfPresent([Model].self, forKey: .data)

下面是我的类(class)的样子:

class JSONResponse<Model>: Decodable
{
    public var data: [Model]?
    public var details: JSONResponseDetails?
    public var errors: [JSONError]?

private enum CodingKeys: String, CodingKey
{
    case details
    case data
    case errors
}

public required init(from decoder: Decoder) throws
{
    let container = try decoder.container(keyedBy: CodingKeys.self)
    details = try container.decodeIfPresent(JSONResponseDetails.self, forKey: .details)
    errors = try container.decodeIfPresent([JSONError].self, forKey: .errors)
    data = try container.decodeIfPresent([Model].self, forKey: .data)

    }
}

Answer 1

通用模型也必须符合Decodable

class JSONResponse<Model : Decodable>: Decodable