duplicates:

• SR-9920 Compiler error when an empty "return" precedes an "@unknown default" case.

Issue Description:

If the final case in a switch statement has a void return statement and you add an @unknown default statement after it, the compiler seems to interpret the default statement as being a continuation of the return. To fix the compiler, you need to explicitly return ().

Sample code exhibiting the issue:

enum Foo {
    case one
    case two
    case three
}

func something(foo: Foo) {
    switch foo {
    case .one:
        break
    case .two:
        break
    case .three:
        return

    @unknown default:
        return
    }
}