What does this parameter type constraint mean?
<p>I am looking at some code and I don't understand what a particular constraint means in the following class definition:</p>

<pre><code>internal abstract class Entity&lt;T&gt; : Entity
    where T : Entity&lt;T&gt;
{ ... }
</code></pre>

<p>I don't understand what this implies about parameter type <code>T</code>.</p>
