title: Resolving extension methods/LINQ ambiguity
body: <p>I'm writing an add-in for <a href="http://en.wikipedia.org/wiki/ReSharper" rel="noreferrer">ReSharper</a> 4. For this, I needed to reference several of ReSharper's assemblies. One of the assemblies (JetBrains.Platform.ReSharper.Util.dll) contains a <code>System.Linq</code> namespace, with a subset of extension methods already provided by System.Core.</p>
  
  <p>When I edit the code, it creates an ambiguity between those extensions, so that I cannot use <code>OrderBy</code>, for instance. How could I solve this? I would like to use the core <a href="http://en.wikipedia.org/wiki/Language_Integrated_Query" rel="noreferrer">LINQ</a> extensions, and not the ones from ReSharper.</p>
  
  <p>I get the following error when trying to compile:</p>
  
  <blockquote>
    <p>The call is ambiguous between the
    following methods or properties:
    '<code>System.Linq.Enumerable.OrderBy&lt;string,int&gt;(System.Collections.Generic.IEnumerable&lt;string&gt;</code>,
    <code>System.Func&lt;string,int&gt;)' and
    'System.Linq.Enumerable.OrderBy&lt;string,int&gt;(System.Collections.Generic.IEnumerable&lt;string&gt;,
    System.Func&lt;string,int&gt;</code>)'</p>
  </blockquote>
  
  <p><strong>EDIT:</strong> I tried the suggestion below, unfortunately without luck. In the meanwhile, I "solved" the problem by removing references to <code>System.Core</code>. This way I could use the extensions provided by ReSharper DLL files.</p>
  
  <p>I <a href="http://a.imagehost.org/download/0589/ClassLibrary1" rel="noreferrer">uploaded a sample program</a> where I just imported the ReSharper DLL files I needed. I changed the alias of <code>System.Core</code> to <code>SystemCore</code>, added the <code>extern alias</code> directive, but it still didn't work. If I missed something, please let me know.
  P.S. The references are to ReSharper v4.1 DLL files installed in the default directroy in <code>"C:\Program Files\JetBrains\ReSharper\v4.1\..."</code>.</p>