KT element: KtWhenExpression
FIR element: FirWhenExpressionImpl
FIR source kind: KtRealSourceElementKind

FIR element rendered:
when (R|<local>/x|) {
    ($subj$ is R|kotlin/String|) ->  {
        String(1)
    }
    else ->  {
        String(2)
    }
}
