Swift enum with custom initializer loses rawValue initializer

Question

I have tried to boil this issue down to its simplest form with the following.

Setup

Xcode Version 6.1.1 (6A2008a)

An enum defined in MyEnum.swift

Answer 1

This works for Swift 4 on Xcode 9.2 together with my EnumSequence:

enum Word: Int, EnumSequenceElement, CustomStringConvertible {
    case apple, cat, fun

    var description: String {
        switch self {
        case .apple:
            return "Apple"
        case .cat:
            return "Cat"
        case .fun:
            return "Fun"
        }
    }
}

let Words: [String: Word] = [
    "A": .apple,
    "C": .cat,
    "F": .fun
]

extension Word {
    var letter: String? {
        return Words.first(where: { (_, word) -> Bool in
            word == self
        })?.key
    }

    init?(_ letter: String) {
        if let word = Words[letter] {
            self = word
        } else {
            return nil
        }
    }
}

for word in EnumSequence() {
    if let letter = word.letter, let lhs = Word(letter), let rhs = Word(letter), lhs == rhs {
        print("\(letter) for \(word)")
    }
}

Output

A for Apple
C for Cat
F for Fun