[SR-5279] Compiler reports: "Switch must be exhaustive" but switch is exhaustive

[swift-ci]

Previous ID	SR-5279
Radar	None
Original Reporter	ngocluu (JIRA User)
Type	Bug
Status	Resolved
Resolution	Done

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug
Assignee	None
Priority	Medium

md5: b30a833a82198122297db51fd5b0c3da

is duplicated by:

• SR-5321 Case Exhaustion Check Bug

Issue Description:

Xcode 9 beta 2 (9M137d)

enum Kind {
    case first(a: Int?, b: Int?, c: Int?, d: Int?, e: Int?, f: Bool?)
    case second(a: Int?, b: Int?, c: Int?, d: Int?, e: Bool?)
    
    var name: String {
        switch self {
        case .first:
            return "first"
        case .second:
            return "second"
        }
    }
}

Adding default case shows warning: "Default will never be executed".

Workaround:

var name: String {
    switch self {
    case .first(_):
        return "first"
    case .second(_):
        return "second"
    }
}

This worked in Xcode 9 beta 1.

[rintaro]

CC/ CodaFi (JIRA User)

This was already fixed in b4f5bc16
Although this commit is not included in Xcode9 beta2, you can try latest Swift 4.0 Development snapshot. https://swift.org/download/#snapshots

Also, I'd advice you not to keep that workaround. If I understand correctly, it wouldn't work when SE-0155 is implemented.