As a professional programmer, I spotted the error on my first read through, but it wasn't a fair test because the code wouldn't have been there if there wasn't a problem. Had I just been scanning the code quickly without being in a state where I was alerted to look for an issue I have no idea if I would have seen it.

In any case, this is something a competent lint tool or static code analyzer would warn about, which makes a good case for people using such tools as part of their normal process.