Swift:“Hashable.hashValue"作为协议要求已被弃用； [英] Swift: 'Hashable.hashValue' is deprecated as a protocol requirement;

问题描述

我的 iOS 项目一直面临以下问题(这只是一个警告).

I've been facing following issue (it's just a warning) with my iOS project.

'Hashable.hashValue' 作为协议要求被弃用；通过实现 'hash(into:)' 来使类型 'ActiveType' 符合 'Hashable'

'Hashable.hashValue' is deprecated as a protocol requirement; conform type 'ActiveType' to 'Hashable' by implementing 'hash(into:)' instead

• Xcode 10.2
• 斯威夫特 5

源代码:

public enum ActiveType {
    case mention
    case hashtag
    case url
    case custom(pattern: String)

    var pattern: String {
        switch self {
        case .mention: return RegexParser.mentionPattern
        case .hashtag: return RegexParser.hashtagPattern
        case .url: return RegexParser.urlPattern
        case .custom(let regex): return regex
        }
    }
}

extension ActiveType: Hashable, Equatable {
    public var hashValue: Int {
        switch self {
        case .mention: return -1
        case .hashtag: return -2
        case .url: return -3
        case .custom(let regex): return regex.hashValue
        }
    }
}

有更好的解决方案吗?警告本身建议我实施 'hash(into:)'，但我不知道，如何?

Any better solution? The warning itself suggesting me to implement 'hash(into:)' but I don't know, how?

参考:ActiveLabel

推荐答案

正如警告所说，现在您应该改为实现 hash(into:) 函数.

As the warning says, now you should implement the hash(into:) function instead.

func hash(into hasher: inout Hasher) {
    switch self {
    case .mention: hasher.combine(-1)
    case .hashtag: hasher.combine(-2)
    case .url: hasher.combine(-3)
    case .custom(let regex): hasher.combine(regex) // assuming regex is a string, that already conforms to hashable
    }
}

删除自定义 hash(into:) 实现(除非您需要特定实现)会更好(在枚举和结构的情况下)，因为编译器会自动为您合成它.

It would be even better (in case of enums and struct) to remove the custom hash(into:) implementation (unless you need a specific implementation) as the compiler will automatically synthesize it for you.

只要让你的枚举符合它:

Just make your enum conforming to it:

public enum ActiveType: Hashable {
    case mention
    case hashtag
    case url
    case custom(pattern: String)

    var pattern: String {
        switch self {
        case .mention: return RegexParser.mentionPattern
        case .hashtag: return RegexParser.hashtagPattern
        case .url: return RegexParser.urlPattern
        case .custom(let regex): return regex
        }
    }
}

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