TonyBai

Aug 20, 2026 · Fundamentals

Polonius Alpha: Rust’s Next‑Gen Borrow Checker Lands on Nightly After Ten Years

Polonius Alpha, the flow‑sensitive next‑generation borrow checker for Rust, has arrived in the Nightly channel, promising to accept code previously rejected by the flow‑insensitive NLL checker, with performance impact largely negligible across thousands of popular crates, while still offering a way to disable it.