- "Crossing the C++/Rust boundary can be difficult."
- "For components that are relatively standalone, with small and simple APIs."
- "This minimizes the C++/Rust boundary layer issues."
Most of Firefox is still (8 years later) not written in Rust.
Chrome with C++ has a waaaaay better safety record than Firefox. Guess what? The C++ in Chrome tries to ensure memory safety for JS.
The C++ Chrome tooling does a better job of memory safety as a whole system than Firefox.
<nit>In part because 1.0 release of Rust popped up in 2015, not 2011.</nit>