title: Which C# compiler errors are undocumented?
body: <p>This is meant to be a collection of possible C# compiler errors that are not documented.</p>
  <p>If you encounter such an error, please post an answer here listing:</p>
  <ul>
  <li>The error number (CS<i>nnnn</i>)</li>
  <li>The associated error message</li>
  <li>If possible, a small snippet of code that will produce the error</li>
  </ul>
  <h3>Example:</h3>
  <blockquote>
  <h2>CS0224:</h2>
  <blockquote>
  <p>A method with vararg cannot be generic, be in a generic type, or have a params parameter</p>
  </blockquote>
  <h3>Produced by:</h3>
  <pre><code>int Foo&lt;T&gt;(__arglist) { return 0; }
  </code></pre>
  </blockquote>
  <p>If someone has already posted an answer listing the error you encountered, then edit that answer to add additional details.</p>
  <p><a href="http://msdn.microsoft.com/en-us/library/ms228296.aspx" rel="nofollow noreferrer">The list of <em>documented</em> errors can be found on MSDN</a>. There seem to be quite a few missing...</p>