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Comment by milesvp

3 days ago

It’s worse than that. Eventually everybody calls into code that hits hardware. That is the level that the compiler (ironically?) can no longer make guarantees. Registers change outside the scope of the currently running program all the time. Reading a register can cause other registers on a chip to change. Random chips with access to a shared memory bus can modify the memory that the comipler deduced was static. There be dragons everywhere at the hardware layer and no compiler can ever reason correctly about all of them, because, guess what, rev2 of the hardware could swap a footprint compatible chip clone that has undocumented behavior that. So even if you gave all you board information to the compiler, the program could only be verifiably correct for one potential state of one potential hardware rev.

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milesvp

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saghm  3 days ago

Sure, but eliminating bugs isn't a binary where you either eliminate all of them or it's a useless endeavor. There's a lot of value in eliminating a lot of bugs, even if it's not all of them, and I'd argue that empirically Rust does actually make it easier to avoid quite a large number of bugs that are often found in C code in spite of what you're saying.

To be clear, I'm not saying that I think it would necessarily be a good idea to try to rewrite an existing codebase that a team apparently doesn't trust they actually understand. There are a lot of other factors that would go into deciding to do a rewrite than just "would the new language be a better choice in a vaccuum", and I tend to be somewhat skeptical that rewriting something that's already widely being used will be possible in a way that doesn't end up risking breaking something for existing users. That's pretty different from "the language literally doesn't matter because you can't verify every possible bug on arbitrary hardware" though.