swift - 对 Enum 的成员 'init(from:)' 的引用不明确

Question

假设我们有这个枚举:

enum NumberEnumSpecial: Int32 {
    case two = 2, three = 3
}

我想用 Int32 初始化它，所以我使用这个:

    let myEnum = NumberEnumSpecial.init(rawValue: 2)

这适用于 playground 项目，但不适用于我的常规 App 项目。对于完全相同的代码，我收到此错误:

Ambiguous reference to member 'init(from:)'

/Users/sjoerd/GitHub/flitsmeister-ios/app/Flitsmeister7/Model/Melding/DangerZone.swift:91:22: error: ambiguous reference to member 'init(from:)'
        let myEnum = NumberEnumSpecial.init(rawValue: 2)
                     ^~~~~~~~~~~~~~~~~
Swift.RawRepresentable:2:24: note: found this candidate
    public convenience init(from decoder: Decoder) throws
                       ^
Swift.RawRepresentable:2:24: note: found this candidate
    public convenience init(from decoder: Decoder) throws
                       ^
Swift.RawRepresentable:2:24: note: found this candidate
    public convenience init(from decoder: Decoder) throws
                       ^
Swift.RawRepresentable:2:24: note: found this candidate
    public convenience init(from decoder: Decoder) throws
                       ^
Swift.RawRepresentable:2:24: note: found this candidate
    public convenience init(from decoder: Decoder) throws
                       ^
Swift.RawRepresentable:2:24: note: found this candidate
    public convenience init(from decoder: Decoder) throws
                       ^
Swift.RawRepresentable:2:24: note: found this candidate
    public convenience init(from decoder: Decoder) throws
                       ^
Swift.RawRepresentable:2:24: note: found this candidate
    public convenience init(from decoder: Decoder) throws
                       ^
Swift.RawRepresentable:2:24: note: found this candidate
    public convenience init(from decoder: Decoder) throws
                       ^
Swift.RawRepresentable:2:24: note: found this candidate
    public convenience init(from decoder: Decoder) throws
                       ^
Swift.RawRepresentable:2:24: note: found this candidate
    public convenience init(from decoder: Decoder) throws
                       ^
Swift.RawRepresentable:2:24: note: found this candidate
    public convenience init(from decoder: Decoder) throws
                       ^
Swift.RawRepresentable:2:24: note: found this candidate
    public convenience init(from decoder: Decoder) throws
                       ^
Swift.RawRepresentable:2:24: note: found this candidate
    public convenience init(from decoder: Decoder) throws
                       ^



Build failed    13/10/2017, 09:32

点击候选人没有任何效果。

如果你问我，代码中某处似乎有一个 Enum，它的 init(from) 实现导致我的 Enum 出现此错误。但是搜索此文本没有任何结果。

这是什么错误以及如何找出导致此错误的原因？

使用 Swift 3.2 和 XCode9.0

目前的解决方法:

enum NumberEnumSpecial: Int32 {
    case two = 2, three = 3

    init?(withSpecialNumber number : Int32) {
          self.init(rawValue: number)
    }
}

Answer 1

我在使用 Xcode 9.2 beta (9C32c) 时遇到了同样的问题，如果它是一个错误，它在这个版本中仍然没有修复。我找到了一种解决方法，可以在不覆盖 init 的情况下使错误消失。

我改变了这个:

 NumberEnumSpecial.init(rawValue: 2)

为此:

 NumberEnumSpecial(rawValue: 2)