polonius

Non-lexical lifetimes [0] are scheduled to be enabled in the Rust 2018 edition, which will be the default edition as of Rust 1.31, the next release. After that, there's still some work that can be done towards NLL, specifically some details around how borrowing across functions works when the compiler "should" know that there actually isn't a borrow. This is part of some work codenamed "Polonius" [1], which should also improve the compiler time required to apply the borrow checker's rules. [0]: https://stackoverflow.com/q/50251487/155423 [1]: https://github.com/rust-lang-nursery/polonius

I was under the impression that the upcoming, shiny, great borrow checker is a tad slow, pathologically so in some cases. https://github.com/rust-lang-nursery/polonius But I do love the way they're tackling the issue know, as this is a much more generic solution.

For some interesting backlog here: As Rust moves from lexical to non-lexical lifetimes, there's been a few different ways of actually implementing it. The initial implementation had some bugs and was fairly slow; but Niko had some other ideas: http://smallcultfollowing.com/babysteps/blog/2018/04/27/an-a... The initial implementation used differential dataflow, but this was just merged in: https://github.com/rust-lang-nursery/polonius/pull/36#issuec... Very cool stuff!