> it's just that the type of people who write in rust are bleeding edge types (for now) and have no consideration for forwards compatibility.
Feels like a pretty blanket statement. I'd assume that they'd base the minimum version on Rust's editions. An edition is released every 3 years and is meant to be a solid LTS (as far as I'm aware) version of the language. If they use Rust 2021 edition, you can tell the compiler that (like C89 vs C11) and it will reject code that's newer. C has plenty of newer stuff too that isn't allowed in kernel code at the moment as well.
Editions aren't that clear-cut- crates targeting old editions can still use most new language features, and all new library features. For example, the NLL borrow checker was originally enabled in the 2018 edition, but it's now available in 2015 as well.
Editions are more designed to manage backwards-incompatible changes, like new keywords or tweaks to corner cases in the type system.
Feels like a pretty blanket statement. I'd assume that they'd base the minimum version on Rust's editions. An edition is released every 3 years and is meant to be a solid LTS (as far as I'm aware) version of the language. If they use Rust 2021 edition, you can tell the compiler that (like C89 vs C11) and it will reject code that's newer. C has plenty of newer stuff too that isn't allowed in kernel code at the moment as well.