Earlier quoted context omitted.
I think if Rust wants to evolve even more aggressively than C++ evolves, then that is a chasm that needs to be crossed. In lots of domains, having a language that doesn't change very much, or that only changes very carefully with backcompat being taken super seriously, is more important than the memory safety guarantees Rust offers.
Isn’t this solution solved by just compiling your libraries with your main app code? Computers are fast enough that this shouldn’t be a huge issue.
- the same entity has access to the source of both the library and the main app
- library and main app share the same build tooling
And even if that’s the case, you have the problem of end users accidentally using different versions of the main app and the library and getting unexpected UB.