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Comment by devmor

11 days ago

> If a compiled safe Rust program has unsound behavior, the compiler needs to be fixed

Can you provide an example of such a program that can’t be fixed at the program level like a C++ example?

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devmor

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_flux  11 days ago

Sure, usually the program can be changed to avoid the issue, but the key here is that the Rust compiler is wrong and needs to be fixed. Once fixed, the actual program fix also falls in place, as it cannot be compiled anymore.

  • devmor  10 days ago

    That’s not an example, that is you restating your post.

    • _flux  10 days ago

      I don't find that anyone made a claim that the program could not be fixed. Why are you suggesting to find a proof of this?

      The point of course was not that what you can do, but what you should do. All cases of safe Rust compiler producing unsound code should be fixed, but the same argument is more difficult to make for C++.

      Sometimes should might be different of what you must. For example, if your program exhibits unsound behavior in safe Rust (or C++) code, it's probably a lot more practical to just change the program so that it doesn't, instead of updating the compiler, unless you happen to be a Rust compiler developer. But, at the same time, you should file an issue about it.

      You can of course find C++ compiler bugs as well, although I expect that to be quite rare nowadays. But the typical case is that if a C++ program exhibits unsound behavior, there is no reasonable compiler fix for it.

      Then there's of course Fil-C! This improves the situation greatly by converting most interesting cases of unsound behavior into runtime errors. It seems not everyone is happy with the runtime costs of making this happen, though. And you must compile everything with Fil-C. It doesn't work with Windows or MacOS either.

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