fun main(args: Array<String>) {
    val current = Test(null, "foobar")

    val ret = with(current) {
        when {
            left != null && right != null -> null
            left != null -> 1
            right != null -> 2
            else -> 3
        }
    }

    println(ret)
}

class Test(
    val left: Any?,
    val right: Any?
)