[tatterdemalion]

There is a conflation happening here. What is the nature of this bug when you compose these two libraries together?

If it is a violation of Rust's safety guarantees, then at least one of those libraries has a bug, it is exposes a safe abstraction which is not actually safe. One could not argue that the safe Rust program is wrong; the library exposing an unsafe interface as safe is unarguably wrong.

If the library just behaves incorrectly in a manner disconnected from the type system because some global state was changed in a way it doesn't expect ("the hardware" in this case), then that's a normal bug & it is not connected to unsafe code at all.

[klodolph]

> then at least one of those libraries has a bug

Yes, we agree about this point. However, the process for determining if these bugs exist is not well understood. That's what I mean when I say that this is not only a pedagogical problem--even Rust experts struggle to prove that a library containing "unsafe" blocks is safe, and more research into the area is needed.

[tatterdemalion]

My apologies if I misunderstood you - I read your comment as suggesting that safe abstractions are "leaky" and therefore create additional responsibilities for users to validate that they are using them safely when composing them together. This is not the case unless those abstractions are incorrect - which is the same situation you are with any language, just most languages those abstractions exist within the language runtime & not in libraries.