Is there a rule to disallow else branches in when statements?

[G00fY2]

Is there already a rule that allows you to report else branches in when statements for exhaustive conditions (enums, sealed classes)?

I am looking for a way to prevent such behaviour.

enum class MyEnum {
    ENUM1, ENUM2, ENUM3, ENUM4
}

Noncompliant Code:

when (type) {
    ENUM1 -> // ok
    ENUM2 -> // ok
    else ->  // detekt should report this else
}

Compliant Code:

when (type) {
    ENUM1 -> // ok
    ENUM2 -> // ok
    ENUM3 -> // ok
    ENUM4 -> // ok
}

Maybe I am missing a rule that does that?

[cortinico]

Yes, it's the RedundantElseInWhen rule :)

[G00fY2]

@cortinico Thanks for answering. Maybe my example code was missing the enum class to make sure what I meant (I edited my initial post).

I think RedundantElseInWhen is only there to find obsolete else branches.

I also tried MissingWhenCase in conjunction with allowElseExpression: false. But this also does not report my example above.

Looks like there is no such rule by now?

[cortinico]

That's correct. Thanks for updating the post. There is no such rule and could be created.

[G00fY2]

Thanks, then my question is answered. Maybe I find time to contribute such a rule. :)

[G00fY2]

I actually added this "missing" rule with #4632