As someone who likes Rust and uses it every day, how have you never screamed at your PC as a direct result of the borrow checker or trait solver? Have you never encountered errors such as higher-ranked lifetime error: failed to prove $FOO: Send, which is sometimes actually just a bug in the compiler? Or the classic the trait bound $FOO: $BAR is not satisfied. axum even has a #[debug_handler] macro just to improve this error. I have spent literal days of my life fixing these kinds of errors, when the compiler not only doesn't provide a solution but fails to pinpoint the cause of the problem.

I can only hope diagnostics continue to improve, because I know they matter to the Rust team.

[–] soulsource@discuss.tchncs.de 3 points 1 year ago

I have seen some errors along those lines (but not exactly those) while working on the Free Monads proof of concept. Especially while trying to come up with a solution that doesn't require macros (which I didn't manage in Stable Rust, exactly due to such issues).

I have yet to see them in actual production code though, but maybe I was just lucky up to now?