ass="pcrr7t-">hiding(null)</span> on the <span 
class="pcrr7t-">import</span><span 
class="pcrr7t-">&#x00A0;Prelude</span> statement. Every module
that imports <span 
class="pcrr7t-">A</span> unqualified, and then makes an unqualified reference to <span 
class="pcrr7t-">null</span> must also resolve the
ambiguous use of <span 
class="pcrr7t-">null</span> just as <span 
class="pcrr7t-">A</span> does. Thus there is little danger of accidentally shadowing Prelude
names.
 <p class="noindent"> It is possible to 