Apple have chosen to go all in on Swift for their first-party code, from the kernel to the libraries to the apps. Even things running on microcontrollers (but there’s no official or standard embedded Swift subset yet).
It’s quite interesting actually that they’ve very intentionally focused on building two-way transition layers so they can start gradually integrating Swift into codebases built in C and Objective-C, and recently new support for C++ and Objective-C++. Which is the best way to do it, big rewrites are the worst, after years of effort you often have a replacement with fewer features than the old one! So being able to replace little bits at a time and write new features in a new language is cool.
They are definitely working a long term plan. The development apple has been doing with identity since they bought NeXT is very sophisticated. I think they are about to make a major push that will put their ecosystem at another level.
It’s quite interesting actually that they’ve very intentionally focused on building two-way transition layers so they can start gradually integrating Swift into codebases built in C and Objective-C, and recently new support for C++ and Objective-C++. Which is the best way to do it, big rewrites are the worst, after years of effort you often have a replacement with fewer features than the old one! So being able to replace little bits at a time and write new features in a new language is cool.
See this talk for the details on that - https://youtube.com/watch?v=lgivCGdmFrw
So don’t expect to see any Rust code from Apple, although of course they might ship third party things written in it at some point.