Rust's `!` never type finally lands on nightly, ending years of limbo
The never type `!` is now stabilized on nightly after a long, crater-checked fight to make it behave as the true bottom type. It lets functions express genuinely-unreachable returns cleanly, replacing the old crate-external `!` hack. The marker change from an uninhabited enum is an intended semver break — but one the ecosystem has been expecting for years.