# [IronPython] defined in multiple assemblies (framework 3.5)

Dody Gunawinata empirebuilder at gmail.com
Mon Aug 18 23:01:03 CEST 2008

```I'm having the same problem. That makes the two of us :) I'm trying to
migrate from Beta 2 to Beta 4. Still diggin'

Dody G.

On Mon, Aug 18, 2008 at 9:53 PM, Fernando Correia <
fernandoacorreia at gmail.com> wrote:

> I'm getting lots of trouble trying to upgrade a C# project that
> embedds IronPython from Beta 1 to Beta 4. We target the 3.5 framework.
>
> The project has some assemblies and a website. I was able to make the
> assemblies compile by adding a reference to Microsoft.Scripting.Core
> and setting the alias to MSCore. In the source code where I use
> IronPython I inserted this line: extern alias MSCore.
>
> But in the website that uses these assemblies, I am getting 244 errors
> like this: The predefined type
> 'System.Runtime.CompilerServices.ExtensionAttribute' is defined in
> multiple assemblies in the global alias; using definition from
> 'c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET
>
> Files\website\4ab7ec98\acce05f3\assembly\dl3\b6dd741b\00e0903e_70f2c801\microsoft.scripting.core.DLL'
>
> and also: 'ExtensionAttribute' is ambiguous in the namespace
> 'System.Runtime.CompilerServices'. InternalXmlHelper.vb.
>
> I can't see a way to assign an alias to a reference in the website,
> since Microsoft.Scripting.Core.dll is just copied to the Bin
> directory.
>
> I think I have the latest version of the framework. Even installed the
> Visual Studio 2008 Service Pack today, along with .NET Framework 3.5
> SP1.
>
> It seems I am stuck with Beta 1... can someone give me some help?
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