title: What is the experimental feature "indexed members"?
body: <p>On the new <a href="http://msdn.microsoft.com/en-us/vstudio/roslyn.aspx" rel="noreferrer">Roslyn Preview site</a> it mentions being able to try out potential language features, and lists three such features.</p>
  <p><img src="https://i.stack.imgur.com/Eml7e.png" alt="screenshot" /></p>
  <p>The first two I've heard of before (for example <a href="http://damieng.com/blog/2013/12/09/probable-c-6-0-features-illustrated" rel="noreferrer">here</a>), but I can't figure out from the code sample what &quot;indexed members&quot; are. Can anyone explain what these are, either based on another source or the code sample? (It's worth nothing <code>$x</code> is not a valid identifier in C# 5.)</p>
  <p><strong>UPDATE</strong> - According to the <a href="https://roslyn.codeplex.com/wikipage?title=Language%20Feature%20Status" rel="noreferrer">Roslyn Feature Status</a> page, this feature has been withdrawn.</p>