Rust always cared about compile times. Much of the motivation to switch from rustboot to rustc was compile times.
(Source: I wrote much of the Rust compiler.)
(Source: I wrote much of the Rust compiler.)
Many foundational crates, serde for example, contribute much more to compile times than they need to.
I spent a long time reinventing many foundational rust crates for my game engine, and I proved its possible to attain similar features in a fraction of the compile time, but it’s a losing battle to forgo most of the ecosystem.
I think a significant portion of our pain with rust compile times is self inflicted due to the natural growth of our crate organization and stages.
I still think the rewrite in zig is the right choice for us for various reasons, but I think at least a chunk of our compile times issues are self inflicted (though this happens to any software project that grows organically and is 300k LOC)
On that note, thank you for your part! I sure enjoy your work! :)
But now it's 2025, and the new version still hasn't been enabled on stable Rust, since the Polonius implementation is seen as far too slow for larger programs. (I'm not exactly sure how horrible it really is, I haven't looked at the numbers.) A big goal of the types team since last year has been to reimplement a faster version within rustc [2].
I'd count this as a language feature (albeit a relatively minor one) that's been greatly deferred in favor of shorter compile times.
[0] https://blog.rust-lang.org/inside-rust/2023/10/06/polonius-u...
[1] https://github.com/rust-lang/rust/pull/51133
[2] https://rust-lang.github.io/rust-project-goals/2024h2/Poloni...
Why aren't people designing modern languages to make it easier to keep a stable ABI, rather than giving up entirely?