Is anybody contemplating nontrivial breaking changes to the standard library? When env::set_var and env::remove_var were marked unsafe, that was done across an

Is anybody contemplating nontrivial breaking changes to the standard library? When env::set_var and env::remove_var were marked unsafe, that was done across an edition boundary even though it's unsound to leave them as-is in older editions. Do you have a particular scenario in mind for incompatible crates? This doesn't seem like a language evolution problem.