There hasn't been a change in scoping between perl versions (AFAIKT); it's always been like that, and it ends up undef on every perl I've tested it on from 5.5003 to 5.9.2. So the behaviour appears to be predictable, but you should't rely on it. For example, saying 'its undefined behaviour' reserves us the right to change its behaviour to something totally random if that makes the internal implementation more efficient.

Dave.