title: lock inside lock
body: <p>I'm wondering if this construction will cause an error:</p>
  
  <pre><code>lock(sync)
  {
    // something
    lock(sync)
    {
      //something
      lock(sync)
      {
        //something
      }
    }
  }
  </code></pre>
  
  <p>I've run this code, and it seems fine, but maybe in some circumstances an error may be thrown?</p>