UFile (package = ) [public final class ReceiverFunKt {...]
    UClass (name = ReceiverFunKt) [public final class ReceiverFunKt {...}]
        UMethod (name = foo) [public static final fun foo($this$foo: java.lang.String) : int {...}]
            UParameter (name = $this$foo) [var $this$foo: java.lang.String]
            UBlockExpression [{...}] = Nothing
                UReturnExpression [return this.length] = Nothing
                    UQualifiedReferenceExpression [this.length] = external length()
                        UThisExpression (label = null) [this] = Undetermined
                        USimpleNameReferenceExpression (identifier = length) [length] = external length()
        UMethod (name = getRx) [public static final fun getRx($this$rx: java.lang.String) : kotlin.text.Regex {...}]
            UParameter (name = $this$rx) [var $this$rx: java.lang.String]
            UBlockExpression [{...}] = Nothing
                UReturnExpression [return [!] UnknownKotlinExpression (CALL_EXPRESSION)] = Nothing
                    [!] UnknownKotlinExpression (CALL_EXPRESSION) [[!] UnknownKotlinExpression (CALL_EXPRESSION)] = Undetermined
    UClass (name = MyReceiverAnnotation) [public abstract annotation MyReceiverAnnotation {...}]
        UAnnotationMethod (name = name) [public abstract fun name() : java.lang.String = UastEmptyExpression]
            ULiteralExpression (value = "") [""] = ""