x00A0;&#x00A0;&#x00A0;&#x00A0;x&#x00A0;=&#x00A0;x&#x00A0;==&#x00A0;0
&#x00A0;<br />&#x00A0;&#x00A0;&#x00A0;&#x00A0;nonNull&#x00A0;x&#x00A0;=&#x00A0;not&#x00A0;(null&#x00A0;x)
</div>
     <p class="noindent"></div>
<p class="noindent"> Module <span 
class="pcrr7t-">A</span> redefines <span 
class="pcrr7t-">null</span>, and contains an unqualified reference to <span 
class="pcrr7t-">null</span> on the right hand side of <span 
class="pcrr7t-">nonNull</span>. The
latter would be ambiguous without the <span 
cl