Court of Lord Zoltan v2

I was going to post this as a question over at SO , but as I got to the end I realised a blog would probably be better (apart from the fact that only five people will read it!). The project I'm working uses runtime objects that are produced with configuration-driven delegates built using Expression trees. I'm doing a big functionality merge at the moment and have reached a class that, because of another that has grown, is now obsolete. So I want to make it 'properly' obsolete (generate compiler errors), go through the static codebase and change all the references. The problem is that the class library is used, through Expressions, by a few other apps so I can't yet get rid of the class completely - I'll perhaps look at farming that job off to somebody else. So I thought I'd just check whether the expression compiler honours the ObsoleteAttribute when marked as an error, and it doesn't: [ TestClass ] public class UnitTest1 {      [ Obsolete ( ...