title: The extern alias 'xxx' was not specified in a /reference option
body: <p>I have two assemblies that unfortunately define the same type in the same namespace.  I'm trying to use a an <a href="http://msdn.microsoft.com/en-us/library/yabyz3h4.aspx" rel="noreferrer"><code>extern alias</code></a> to work around the problem.  In the Visual Studio IDE I have set the "Aliases" property of the reference to my alias.  This is supposed to change the C# compiler command line to be something like this:</p>
  
  <pre><code>/reference:MyAlias=MyAssembly.dll
  </code></pre>
  
  <p>But it doesn't actually do that.  The Visual Studio IDE seems to just ignore the Aliases property setting on the reference.  So when I go and add the line <code>extern alias MyAlias;</code> at the top of my C# code file I get the error that the alias was not specified in a /reference option to the compiler.  I can't figure out what I am doing wrong.  Any ideas?</p>