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by AlotOfReading 363 days ago 

    In a language with the `unsafe` construct and effectively no automated tooling to audit the uses of it.
You can forbid using unsafe code with the lints built into rustc: https://doc.rust-lang.org/stable/nightly-rustc/rustc_lint/bu...

Cargo allows you to apply rustc lints to the entire project, albeit not dependencies (currently). If you want dependencies you need something like cargo-geiger instead. If you find unsafe that way, you can report it to the rust safety dance people, who work with the community to eliminate unsafe in crates.

All of this is worlds ahead of the situation in C++.
1 comments
vlovich123 363 days ago
OP is wrong that there's no tooling. All the C++ tooling that I'm aware of (e.g. ASAN/UBSAN/MSAN/TSAN) is still available on Rust. Additionally, it has MIRI which can check certain code constructs for defined behavior at the MIR level which, unlike sanitizers, validates that all code is sound according to language rules regardless of what would be run by generated assembly; this validation includes unsafe code which still has to follow the language rules. C/C++ doesn't have anything like that for undefined behavior by the way.

However, if I can apply a nitpicking attitude here that you're applying to their argument about the ease with which unsafe can be kept out of a complex codebase. unsafe is pretty baked into the language because there's either simply convenient constructs that the Rust compiler can't ever prove safely (e.g. doubly-linked list), can't prove safely today (e.g. various accessors like split), or is required for basic operations (e.g. allocating memory). Pretending like you can really forbid unsafe code wholesale in your dependency chain is not practical & this is ignoring soundness bugs within the compiler itself. That doesn't detract from the inherent advantage of safe by default.

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AlotOfReading 363 days ago
I do safety critical code. I would consider banning allocation (e.g. just using Core) or avoiding certain data structures a completely feasible strategy to avoid unsafe if I wanted to exclude it from my safety model. It's what I'm already doing in C++. The difference is that in C++, I can never prove the absence of undefined behavior from any part of the codebase, even if I review every single line. Even if I could, that proof might be invalidated by a single change anywhere.

It's not easy in Rust, but it's possible.

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