I actually tried that, and it causes problems when reloading packages, as was the case with #168. The problem happens when a class B in a package has a reference to another class A (that's not in the package), and A has a reference back to B. If you remove all the `B@contains` references and then remove `B`, then A has a dangling reference back to B. When you try to create a class B again, you get errors because it tries to modify A to have a reference to B, but that reference already exists.

In the case of 168, the analog of class A was `oldClass`. And I think the problem happened with another class as well.