Here's what we recommend as a workaround.<div><br></div><div>The CodePlex work item that tracks this request (<a href="http://www.codeplex.com/IronPython/WorkItem/View.aspx?WorkItemId=19126">http://www.codeplex.com/IronPython/WorkItem/View.aspx?WorkItemId=19126</a>) now contains a modified version of Microsoft.Scripting.ExtensionAttribute.dll. For this one particular case, where simultaneous referencing of the original version of our assembly and System.Core.dll causes problems, you can replace the "shipping version" of our DLL with the modified version. This will eliminate the "is ambiguous" error message.</div>
<div><br></div><div>The magic that makes this work is called "type forwarding". The updated DLL simply contains a type forwarder to System.Core for the type System.Runtime.CompilerServices.ExtensionAttribute. As a result, there is no second copy of that class, and the CLR loader redirects all references from the rest of IronPython to System.Core.</div>
<div><div><br></div><div>This file, though strongly-named and signed, is even more "not supported" than the rest of IronPython :). By this I mean primarily that we haven't run any test passes using the new assembly, and don't plan to. However, as it doesn't actually contain any code, the risks from this modified version should be very small.</div>
<div><br></div><div>We hope to address this problem differently for the next release, but our promise to stay compatible with .NET 2.0 for this release has somewhat constrained the type of solution we are able to offer. Thanks for your patience!<br>
<br><div class="gmail_quote">On Thu, Oct 23, 2008 at 9:56 AM, Fernando Correia <span dir="ltr"><<a href="mailto:fernandoacorreia@gmail.com">fernandoacorreia@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
I'm trying to upgrade from Beta 5 to RC1 and I'm getting, again, errors trying to build an <a href="http://ASP.NET" target="_blank">ASP.NET</a> 3.5 website that uses IronPython.<br><br>The errors are similar to what happened with Beta 1:<br>
<br>(0,0): warning CS1685: The predefined type 'System.Runtime.CompilerServices.Ex<div>tensionAttribute'
is defined in multiple assemblies in the global alias; using definition
from 'c:\WINDOWS\assembly\GAC_MSIL\System.Core\3.5.0.0__b77a5c561934e089\System.Core.dll'<br><br>InternalXmlHelper.vb(9,0): error BC30560: 'ExtensionAttribute' is ambiguous in the namespace 'System.Runtime.CompilerServices'.</div>
<br>I opened issue 19126 with more details.<br><br>Regards,<br><font color="#888888"><br>Fernando.<br><br><br>
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