I'm not saying it's a bug. I'm saying that backwards compatibility means that you still have to deal with all of the historic flaws of the language today.
But that’s true for literally everything. If you have a cpp code base and are building new stuff in rust to interop then you still have legacy cpp code even though rust has fewer problems.
Not really. Legacy stuff can be contained. For example, you could specify language version level in file and it would disable removed/deprecated stuff.