why the following rule has a warning when I compile it.
<rule id="Rule1" scope="public">
<one-of>
<item>Hey</item>
<item>
<item>this is</item>
<ruleref special="GARBAGE"/>
<item>speaking</item>
</item>
</one-of>
</rule>
The compiled warning is "Wildcard should be contained within an element that is both optional and has no semantic tag."
Thank you for your help!