The concept of lifetimes was invented long before Rust borrow checker was even "scratched on paper." Of course, people who understand what they are they doing have known about these concepts for decades and have built their architectures around them. However, Rust borrow checker is much stricter than that. You have to build your architecture around the fact that you can't have more than one mutable reference at a time, and your data structures have to be represented as directed, acyclic graphs, etc. If you have to break all these rules by using a lot of unsafe because it's too difficult to represent your system within Rust safe subset using only value semantics and borrow-checked references, etc, then why use Rust instead of C++, C, or Zig?
What I mentioned is only a tiny part of the entire software, which has been successfully written in C, C++, and now in Zig as well, and is used daily by people around the world.
For 99.99% of cases, you're reading and writing this under an operating system whose kernel is written in a language without send/sync, and inside a browser that also largely written in languages without send/sync, because those systems are fundamentally well designed. So instead of fixing the bugs and rethinking the architecture, the author of Bun decided to transpile almost the entire codebase from Zig to Rust without a deep architectural review. Okay...
If you use Rust the way it was designed to be used, rather than relying on countless "unsafe" blocks, you need to redesign the entire codebase architecture to make it compatible with the borrow checker rules.
To me, this whole effort of rewriting Bun from Zig to Rust looks like a big marketing move. The question is: if Anthropic AI is really that powerful, why not just fix the bugs and give it the more ambitious task of redesigning the existing Bun Zig codebase in a way that eliminates not only the current bugs but also prevents similar ones from happening in the future?
2664 "unsafe {", 1835 "unsafe fn". This is completely unsafe. It doesn't look like a rewrite that understands what's actually going on or how the architecture should be redesigned to take advantage of Rust strengths. Instead, it looks like an AI generated transpilation with extensive use of raw pointers.
The biggest advantages of Zig for me are that everything is explicit (no hidden features like overloads or implicit conversions) and that its metaprogramming is powerful, easy to use, and easy to understand.
Just look at this: https://pvs-studio.com/en/blog/posts/cpp/1129/ - 11 parts about C++ undefined behavior from people who specialize in finding this stuff. And that’s only the tip of the iceberg.
I use C++ daily, and it’s an overcomplicated language. The really good thing about Rust or Zig is that (mostly) everything is explicit, and that’s a big win in my opinion.
In defense of C++, I can only say that lots of interesting projects in the world are written in it.