title: Why can't List<parent> = List<child>?
body: <p>Why won't the following code work?</p>
  
  <pre><code>class parent {}
  class kid:parent {}
  
  List&lt;parent&gt; parents=new List&lt;kid&gt;;
  </code></pre>
  
  <p>It seems obvious to me. What's going on here?</p>