[jandrewrogers]

In my experience, rewriting C++ into Rust is non-trivial because idiomatic C++ expresses things that Rust cannot. This impedance mismatch breaks architecture, and that often isn’t allowed in a rewrite. I’ve seen multiple C++ rewrite attempts fail because of poor interoperability with Rust’s constraints. Language interoperability that is high quality and low friction matters to people, and in the case of C++ that is decidedly challenging.

My view at this point is that you are better off starting from a clean sheet of paper in Rust than trying to make Rust do C++ things it was not designed to do.

In the specific narrow case of performance-engineered code, Rust also seems to consistently produce slower code in my experience for myriad weird reasons, it isn’t one thing. In many cases I don’t even think it is the fault of the language per se, just a side effect of other factors. Nonetheless, customers don’t care about any of that, they won’t accept a performance regression just because you rewrote it.

[zozbot234]

Idiomatic "modern C++" as defined by the Core C++ Guidelines is very similar to Rust, it even has its own bespoke ownership+lifetime checking mechanism.

[steveklabnik]

Do you know if any big public projects using the GSL or similar? I haven’t found any but I’d like to check them out.