title: Swift compiler inconsistency with operator +=
body: <p>Compiler seems inconsistent with its compilation for +=.  Any idea why the last line has issue?</p>
  
  <pre><code>var num = 2;
  num += 2 //Works
  num+=2 // Works
  num +=2 //Error: Consecutive statements on a line must be separated by ;
  </code></pre>