I think you already had plenty of good advices on this thread,
however I'd like to add a question and a comment :
Assuming that your goal was to make this guy code better :
Why didn't you try to talk to the coder first ?
You could have made him explain why he choosed to code this way.
You could even have made him understand why it's bad!
Don't get me wrong I'm not talking about morale/ethics/good...
I'm talking about efficiency.
When communicating with people you'll have to take as the fact that people listen/understand what you say
depending on the way/the moment/the context you say it.
Keeping that in mind, I'm pretty sure that he won't integrate your (good) advices during the planned meeting
which will now probably sound more like a court for him...
(He'll be the central point of a discussion about what he did wrong in front of judges(managers))
Usually you can't have efficient discussion with people on defensive...
It wouldn't have been the same if you had explained it to him, man to man, in front of a beer...
Just a "I've seen some problems but I talked to the coder and he will correct them soon" would have been fine with your manager, IMHO.
I'm not saying you did wrong ! I just show you another way to try, next time.
"Only Bad Coders Code Badly In Perl" (OBC2BIP)