title: Strange Swift numbers type casting
body: <p>I've just noticed that Swift does some type casting over Int and Double.
  When I try to evaluate</p>
  
  <pre><code>(10 / 3.0) - (10 / 3)
  </code></pre>
  
  <p><code>0.333...</code> is expected, but it's actually <code>0.0</code>.
  Could someone explain this please?</p>