It depends. I migrated a 20k loc c++ project to rust via AI recently and I would say it did so pretty well. There is no unsafe or raw pointer usage. It did add Rc<RefCell in a bunch of places to make things happy, but that ultimately caught some real bugs in the original code. Refactoring it to avoid shared memory (and the need for Rc<RefCell<>> wasn't very difficult, but keeping the code structure identical at first allowed us to continue to work on the c++ code while the rust port was ongoing and keep the rust port aligned without needing to implement the features twice.
replyI would say modern c++ written by someone already familiar with rust will probably be structured in a way that's extremely easy to port because you end up modeling the borrow checker in your brain.
Yes, I just translated a Rust library from non-idiomatic and unsafe Rust to idiomatic and safe Rust and it was as much work as if I had rewritten it from scratch.
replyyeah, matches what I'd expect. when you're porting idiomatic -> idiomatic within a language, the cleanup is mechanical. crossing from C++ to Rust means the borrow checker surfaces assumptions that were latent in the original code, so you end up redesigning rather than translating. that's not a complaint about Rust -- it's actually doing its job.
replyThis is what I was trying to highlight in my post.
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