This is pretty silly. I mean -- this happens, but this happens to any language, because as others have noted: forwards compatibility isn't a thing. New featur

This is pretty silly. I mean -- this happens, but this happens to any language, because as others have noted: forwards compatibility isn't a thing. New features will be added, and, given the track record of Rust, these new features have been pretty good! I recently experienced this relatively trivial issue -- I had only tested some software with the latest stable Rust version, 1.62. A user reported it was not building on the Ubuntu default installed 1.59, and I decided building on that version of Ubuntu was worth it. The fix? Install and use the relevant rust toolchain `rustup default 1.59`, `cargo check` points out exactly the issue (BTW the language change was a good change!), fix and push. It was so easy.