UFile (package = ) [public final class WhenIsKt {...]
    UClass (name = WhenIsKt) [public final class WhenIsKt {...}]
        UMethod (name = foo) [public static final fun foo(bar: java.lang.Object) : void {...}]
            UParameter (name = bar) [var bar: java.lang.Object]
            UBlockExpression [{...}] = Nothing
                UReturnExpression [return [!] UnknownKotlinExpression (WHEN)] = Nothing
                    [!] UnknownKotlinExpression (WHEN) [[!] UnknownKotlinExpression (WHEN)] = Undetermined
