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)
    }
}

FIR FILE:
FILE: [ResolvedTo(IMPORTS)] whenExpression.kt
    public final [ResolvedTo(BODY_RESOLVE)] fun foo([ResolvedTo(BODY_RESOLVE)] x: R|kotlin/Any|): R|kotlin/String| {
        ^foo when (R|<local>/x|) {
            ($subj$ is R|kotlin/String|) ->  {
                String(1)
            }
            else ->  {
                String(2)
            }
        }

    }