title: Why is !0 a type in Microsoft Intermediate Language (MSIL)?
body: <p>In many MSIL listings, I have observed the following:</p>
  
  <pre><code>System.Nullable`1&lt;!0&gt; etc ...
  </code></pre>
  
  <p>or</p>
  
  <pre><code>class !0 etc ...
  </code></pre>
  
  <p>What's the meaning of <code>!0</code> in these circumstances?</p>