Rust Borrow Checker 2.0 is Finally Here
Polonius, the next-generation Rust borrow checker, is now enabled by default on Nightly, resolving long-standing false positives from Non-Lexical Lifetimes (NLL) in conditional branches and common data structures like HashMap. Benchmarks across the top 10,000 crates show minimal compile-time regressions despite more precise control-flow analysis. The Rust team prioritizes correctness over pure compilation speed, giving developers more flexibility without sacrificing memory safety.