title: F#: always "unexpected 'when' keyword"
body: <p>The VS2010 Beta 2 F# compiler always complains about my usage of the when keyword, even when using copy-pasted code which is supposed to work, such as either of <a href="http://diditwith.net/2008/04/24/YetAnotherProjectEulerSeriesYAPES.aspx" rel="noreferrer">these snippets</a>. For instance, this is the error I get when trying to execute a very trivial expression:</p>
  
  <p>"Error FS0010: Unexpected keyword 'when' in expression. Expected '->' or other token.  "</p>
  
  <pre><code>[for i in 1..50 when i &lt; 10 -&gt; i]  
  ---------------^^^^
  </code></pre>