UFile (package = )
    UClass (name = ReceiverFunKt)
        UMethod (name = foo)
            UParameter (name = $this$foo)
            UBlockExpression
                UReturnExpression
                    UQualifiedReferenceExpression
                        UThisExpression (label = null)
                        USimpleNameReferenceExpression (identifier = length)
        UMethod (name = getRx)
            UParameter (name = $this$rx)
            UBlockExpression
                UReturnExpression
                    [!] UnknownKotlinExpression (CALL_EXPRESSION)
    UClass (name = MyReceiverAnnotation)
        UAnnotationMethod (name = name)
            ULiteralExpression (value = "")
