Indeed, it introduces subtle bugs related to indexing pretty often. At one point I had it autocomplete maybe 15 lines of code, and I trusted it because the code was all pretty easy and I had written a descriptive comment, which tends to help out Copilot a lot.

However, it introduced a very subtle bug where it used a loop counter `i` where it should have been indexing into an array like `arr[i]`, but it still typechecked and happened not to cause insane errors. Took a lot of time to track down later, and it's a bug I never would have written in myself.