[swift-users] Handle deprecated enum cases from a library

Dennis Weissmann dennis at dennisweissmann.me
Mon Nov 6 05:47:36 CST 2017

Hey Charles,

Thanks for going through this with me :)

I'm not sure whether or not this is a compiler bug (that's partially why I posted it here), although I have the feeling that *something* is definitely wrong.

Funnily enough, the following code shows 3 compiler warnings which are incorrect:

private func handleLocalAuthenticationError(_ error: LAError) {
    switch error.code {
    case .userCancel, .appCancel, .systemCancel:
        print(".userCancel, .appCancel, .systemCancel")
    case .authenticationFailed:
    case .passcodeNotSet:
    case .biometryNotEnrolled, .touchIDNotEnrolled:             // Compiler: Case will never be executed
        print(".biometryNotEnrolled, .touchIDNotEnrolled")
    case .biometryNotAvailable, .touchIDNotAvailable:           // Compiler: Case will never be executed
        print(".biometryNotAvailable, .touchIDNotAvailable")
    case .biometryLockout, .touchIDLockout:                     // Compiler: Case will never be executed
        print(".biometryLockout, .touchIDLockout")
    case .userFallback:
    case .invalidContext:
    case .notInteractive:

let error = LAError(.touchIDLockout)

When you run it in a playground, you can see that the case *gets* executed.

- Dennis

> On Nov 5, 2017, at 7:13 PM, Charles Srstka <cocoadev at charlessoft.com> wrote:
>> On Nov 5, 2017, at 10:39 AM, Dennis Weissmann <dennis at dennisweissmann.me <mailto:dennis at dennisweissmann.me>> wrote:
>>> You can delete the default case here, and your switch will still be exhaustive
>> That's exactly my problem! It is *not*.
>> When I delete the default clause, the compiler warns that the switch is not exhaustive and fixits suggest to add the "missing" deprecated cases.
>> - Dennis
> Hi Dennis,
> Ah, I see—although the switch should be considered exhaustive since you have covered all the possible cases, the compiler is claiming that it is not. I would probably consider this to be a compiler bug. Have you considered filing a report at bugs.swift.org <http://bugs.swift.org/>?
> Charles

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