I still don't see it being much different from using language switches, especially when language semantics, ABI across versions, and standard library are part of the whole upgrade story.
Additionally I have my doubts how long this will scale when Rust has like 40 years of history behind it.
> I have my doubts how long this will scale when Rust has like 40 years of history behind it.
We've been doing this for 10 years already, so if the cost is linear, it shouldn't be a problematic burden over another 30 years. It helps that editions don't need to be big. Just checked the codebase and there are exactly 70 gates for "at least edition X" (2018 21, 2021 19 and 2024 30) and 16 for "is edition 2015" (2 in the parser, most of the rest in name resolution).
Additionally I have my doubts how long this will scale when Rust has like 40 years of history behind it.