ruby-debug/ruby-debug — pull request #12 by enebo (2012-12-14 17:02:12+00:00)
Title: nil can sometimes exist in context stack in 1.9...Even if this is not th...

...e case we have no reason to cast here since we only care about object equality

It could be a bug that contexts are nil at times but the commit itself should be fine regardless since we only care about a match against a specific object.