Comment by tick_tock_tick

6 months ago

I mean we know for sure Rust is unsafe there is whole bug tracker dedicated to all the ways it's unsafe. My favorite is that you can cast any lifetime to static no matter how short it actually is in 100% safe Rust.

(doesn't mean it's not an improvement on C++)

5 comments

tick_tock_tick

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krukah  6 months ago

I think referencing the well-known cases in cve-rs[1] is quite a bad faith effort. Of course if you try reeeally hard to write unsound code, you can write unsound code. An edge case in the type system downstream of lifetime variance rules is simply not something that matters in any practical attempt to write safe software. I find the tracker interesting since it probes the boundary of the compiler, but it says absolute nothing to the effect of "Rust is unsafe".

[1] https://github.com/Speykious/cve-rs

ViewTrick1002  6 months ago

The unsound bug tracker is were my heart gets all warm and fuzzy in Rust land.

All the ways to coerce and poke the implementation of what should be safe constructs to produce unexpected garbage - and people spending time fixing the issues because they are treated as bugs.

It’s like the best possible advertisement for ”we enable soundness and correctness for all your programs.”

https://github.com/rust-lang/rust/issues?q=state%3Aopen%20la...

selfmodruntime  6 months ago

This doesn't 'cast' anything. The compiler prevents this because it would allow references that outlive their owners. Freely 'casting' only works for data that is static in nature anyways, at which point a coercion is taking place. Any other way involves `std::mem::transmute` or `Box::leak` and the like.