Polonius: Either Borrower or Lender Be, but Responsibly - Niko Matsakis

Rust 2018 brought with it “non-lexical lifetimes” (NLL), a big overhaul of how the borrow checker worked that allowed it to accept a lot more programs. And yet, we’re still not accepting the full range of programs that was envisioned by the original NLL RFC – this is both for performance reasons and because the formulation didn’t turn out to be as flexible as originally thought.