Rust isn't standardized. Last time I checked, everyone who uses it depends on its nightly build. Their toolchain is enormous and isn't vendorable. The binaries it builds are quite large. Programs take a very long time to compile. You need to depend on web servers to do your development and use lots of third party libraries maintained by people you've never heard of, because Rust adopted NodeJS' quadratic dependency model. Choosing Rust will greatly limit your audience if you're doing an open source project, since your users need to install Rust to build your program, and there are many platforms Rust doesn't support.

Rust programs use unsafe a lot in practice. One of the greatest difficulties I've had in supporting Rust with Cosmopolitan Libc is that Rust libraries all try to be clever by using raw assembly system calls rather than using libc. So our Rust binaries will break mysteriously when I run them on other OSes. Everyone who does AI or scientific computing with Rust, if you profile their programs, I guarantee you 99% of the time it's going to be inside C/C++ code. If better C/C++ tools can give us memory safety, then how much difference does it really make if it's baked into the language syntax. Rust can't prove everything at compile time.

Some of the Rust programs I've used like Alacrity will runtime panic all the time. Because the language doesn't actually save you. What saves you is smart people spending 5+ years hammering out all the bugs. That's why old tools we depend on every day like GNU programs never crash and their memory bugs are rare enough to be newsworthy. Finally, the Rust community has a reputation for toxic behavior that raises questions about its the reliability of its governance.

You may want to refresh your familiarity with Rust, I haven't touched nightly in ages and much of what you mention doesn't really resonate with what I've seen in practice. Not saying the language doesn't have issues and things that aren't frustrating but in my experience unless you're going to go to the nines in testing/validation/etc (which is the first thing that's cut when schedules/etc are in peril) I've seen Rust code scale better than C++ ever did.

More tools in the C/C++ realm are always welcome but I've yet to see more than 50% of projects I've worked on be able to successfully use ASAN(assuming you've got the time to burn to configure them and all their dependencies properly). I've used ASAN, CBMC and other tools to good effect but find Rust more productive overall.

> One of the greatest difficulties I've had in supporting Rust with Cosmopolitan Libc is that Rust libraries all try to be clever by using raw assembly system calls rather than using libc.

I’m sorry, this is coming from Justine “the magic syscall numbers are my god given right to use” Tunney?

Seems like it depends entirely on context. I'd expect code which intends to be portable to use some sort of dynamically linked wrapper, even if that wrapper isn't libc.

It's the stated mission of my project. Rust's stated mission is memory safety.

So using raw system calls is a distraction for them.