Why no C# Edit and Continue?

I received an email from Bill T. who was asking why C# wont be doing Edit & Continue (EnC as we refer to it) in VS “Whidbey”. He asked “I've always wondered WHY that's so much more difficult in C#.  Perhaps you could write something in your blog describing the technical issues that make it difficult.  I'd love to know some of the rationale behind it“. Here goes:

We on the debugger team obviously contributed a bunch of work for VB EnC to work in “Whidbey“ along with the VB compiler and CLR teams. For the debugger, the additional work to support additional languages is close to zero. For C# EnC the work would require substantial resources on the C# compiler and C# IDE teams. For “Whidbey“ we asked customers and prioritized Generics and Refactoring as more important than EnC for C#. It is not that the C# team has anything against EnC, it was just a resource issue. It is highly likely it will show up in a future version of VS.

Hope that helps Bill, and thanks for the question.

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