title: Need help to understand how scala list.contains works
body: <p>why is it that something like: </p>
  
  <pre><code>val map = Map(....)
  
  List(1,2,3,4).contains(map)
  </code></pre>
  
  <p>or </p>
  
  <pre><code>List(1,2,3,4).contains("hello")
  </code></pre>
  
  <p>Are allowed to compile. I though scala was type safe.</p>