[BD103]

Technically yes, but editions are more like different "flavors" of Rust than actual breaking changes. A 2021 crate is supposed to be able to import a 2018 crate, likewise for 2015 and 2024. Because they all need to work together, edition changes still need to be somewhat compatible with older versions.

Because you can pass closures into functions across crate boundaries, which requires consistent lifetime semantics, I find it unlikely that this will be implemented.

[afdbcreid]

As far as I can tell, this change is compatible with other editions. Closures can already be higher-ranked, and changing closures to be higher-ranked will work with existing editions.

A more problematic thing is that `cargo fix --edition` should be able to transform existing code to the same meaning in a new edition, so there should be a way to opt-in for the old behavior.