title: How to get rid of 'Name ... used only once: possible typo at ...'?
body: <pre><code>use YAML::XS;
  local $YAML::XS::DumpCode=1;
  ...
  </code></pre>
  
  <p>I get the warning:</p>
  
  <pre><code>Name "YAML::XS::DumpCode" used only once: possible typo at ..
  </code></pre>
  
  <p>Well, I know I can suppress this specific warning, but it's kind'a ugly. Am I doing anything wrong? I'm not used to be warned :)</p>