Swift: 'Hashable.hashValue' is deprecated as a protocol requirement;

问题

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

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

• Xcode 10.2
• Swift 5

Source Code:

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
        }
    }
}

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

Reference: ActiveLabel

回答1:

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
    }
}

TIP: you don't need to make the enum explicitly conforms to Equatable because Hashable extends it.

来源：https://stackoverflow.com/questions/55395207/swift-hashable-hashvalue-is-deprecated-as-a-protocol-requirement