[ldng]

The argument Rust devs make is that most of the time you would not need to use unsafe code and when you do, being explicit about it would make you more careful and think twice about it.

To me it makes sense. And the example you give here is very relevant. First you'd try to do it within the standard language bounds and only when you realize you can't do it that way, I'll resort to unsafe code. But now your very aware that this part of the code needs to be treated why extra care. So, to me, you're not completely back to square one.

Nicholas Matsakis make this very point near the end of this talk: https://www.youtube.com/watch?v=9wOzjbgRoNU

I would even add, if care is taken to make that unsafe code really small it can even been generated by Coq for instance as stated in some comments here.

That said Rust might not be the best out there for the job but IMHO it shouldn't be dismissed to fast either. It is similar enough to C++ to allow a less painful transition for devs with the domain knowledge.

[NateDad]

Would you not assume that the entire OpenSSL library would count as being in need of extra scrutiny? The point is that any time you let people directly access memory, they can, and often will, screw it up.

[ldng]

Ok, maybe we should make a distinction between, let's say the plumbing code and algorithms. Rust could help with the former. According to some comments I've read here it seems OpenSSL is using it's own abstraction of malloc/free (not that I have actually read the code). I suppose that this part of the code would be a suitable candidate for unsafe code with special extra care taken, then the rest of the algorithm does not not to be unsafe code. If you watch the video you might understand better what I mean : the ARC is unsafe but provide you with a safe abstraction for you to use in the checked part of the language.

Of course such a project must require extra scrutiny on all level and Rust does not resolves all the problems. I'd say pick your battles. Rust provide some interesting middle ground between C/C++ and a completely different language like Ada.

[eatfish]

Oh, I'm not dismissing Rust. I think my overall point is that nothing is ever going to perfect. Plan for imperfection.