Looks like somewhere along the lines my comment got interpreted as criticism rather than merely an observation, that wasn't my intent. Anyway I'm not suggestin

Looks like somewhere along the lines my comment got interpreted as criticism rather than merely an observation, that wasn't my intent. Anyway I'm not suggesting they find it elsewise. In fact as you rightfully pointed out finding bugs like this is incredibly hard. However surely those code-generator bugs could have been spotted earlier? The reason they weren't was because they didn't cause any obviously wrong behaviour, which made it hard to find them using test, but as long as you pay attention you can still spot them (as evidenced by the fact that they were eventually fixed). So if you're wondering how a bug like this might have slipped past their 'extensive test coverage', I felt it was important to point out that putting too much trust in those test is also a viable explanation. Not necessarily the right explanation, as I have no way of knowing the situation at SQLite, but a possible explanation.