RedundantElseInWhen.md

Pattern: Redundant else in when

Issue: -

Description

Turn on this rule to flag when expressions that contain a redundant else case. This occurs when it can be verified that all cases are already covered when checking cases on an enum or sealed class.

Example of incorrect code:

enum class Color {
    RED,
    GREEN,
    BLUE
}

fun whenOnEnumFail(c: Color) {
    when(c) {
        Color.BLUE -> {}
        Color.GREEN -> {}
        Color.RED -> {}
        else -> {}
    }
}

Example of correct code:

enum class Color {
    RED,
    GREEN,
    BLUE
}

fun whenOnEnumCompliant(c: Color) {
    when(c) {
        Color.BLUE -> {}
        Color.GREEN -> {}
        else -> {}
    }
}

fun whenOnEnumCompliant2(c: Color) {
    when(c) {
        Color.BLUE -> {}
        Color.GREEN -> {}
        Color.RED -> {}
    }
}

Further Reading

• Detekt - RedundantElseInWhen