That what I meant by "I can see what they were trying to do". It's would have been correct if the "+x" was inside the braces, even in context. He did in fact want to check if the variable was unset and error out, and that's what hurts so much.
There was a real and correct analysis that, hey, I want to make sure the variable is set here. Only to then drop it because you get told the syntax is wrong. The response I'm looking for when I say "This syntax won't do what you're looking to do" would be something like "what am I trying to do? and why wont this do it?" not "well it's just some AI code, I'll just remove it".