Here’s the difference imo, an average programmer with some experience would seek out well tested and used library to help them do something like this, not use sausage meet spat out of a cannon to validate email addresses.

I’d hope so, but then again, this is what their ML model spat out, which suggests people have written stuff like this, though hopefully not the wonkiness around the bit after the last dot.

But on the brighter side, the material the user provided to Copilot in this case was pretty much “I want to implement email validation from scratch” rather than “I want to validate an email address”, which is where hopefully people would look more to existing libraries. And they’ll commonly already such libraries or functions in their code base, e.g. under Django you’d use… uh oh, searching found https://stackoverflow.com/q/3217682/ first which looks frighteningly familiar here in half of the errors it contains; but anyway, you should use https://docs.djangoproject.com/en/3.2/ref/validators/#emailv.... I suspect the Copilot approach as used will be unintentionally biased much more towards boilerplate and implementing things from scratch, rather than using libraries.

>about as good as the average programmer who's going to validate E-Mail with regexes would

IMHO, the average programmer is not even aware of regexs, which is a problem, but here would lead the programmer to a simpler to read solution.

You need to be at a very particular point (good enough to be proficient with regexs, but bad enough to use them for everything and bad enough to not test your regex), and I strongly doubt that's the average.

P.S. The video question was to validate emails, not 'validate using regex'.