Back in February of '04, I posted “.Net says - multiple languages supported. VS.Net says - don't try it“. A quick response by Paul Vick showed that it would probably never be fixed for Visual Studios 2002 and 2003 - but that they'd work on it for Whidbey.
Alas, the beta 1 and multiple CTPs came and went, and the bug continued. However, I am happy to report that in VS.NET 2005 Beta 2, the problem seems to have been resolved. My test case now works, and I'm a happy camper.
Thanks to the background compilation teams for c# and vb.net! While I'm sure this is an edge case, it's an edge that's cut me more than once.
Now if only Paul would allow us to turn off VB.Net default form instance codegen by the compiler, and make lots of friends. (sure - keep the feature, but make it opt-in, or at least opt-out)