njackson/DCI-Rails — pull request #1 by markburns (2012-03-30 16:07:49+00:00)
Title: I think it's better to blow up when accidentally extending nil using DCI

This overrides extend on nil. TBH I'm not sure if that could cause problems - i.e. if other libraries actually extend nil and depend on it, but it seems like it would be a dangerous thing to do, so seems safe to try to prevent people from doing it.