Did you have enjoy thinking about the problem? I definitely had fun during this weekend, pictures will be put on the website soon.
But back to the question off last friday, what will be the result? It would not have surprised me if PHP would raise a NOTICE, but this is not the case. It might have surprised me if PHP used the last statement in the definition as the result, but this is also not the case. The variable $result is just null, not initialized, nothing happens! This is probably not the intention of a programmer, either the function is misspelled or the function is not correctly implemented. So this pattern is added to the correctness-category and has id C005.
I have also worked on the constant-propagation again. There is now support for superglobals and the list-statement. The support for superglobals also implies that every variable is also accessible through the $GLOBALS array.