Compatibility with C++ is required at this point in time to interface with the thousands of lines of C++ code that have already been written. Assuming that everything will be written in Jakt at some point, then one could look into making more grave changes without having to care about compatibility (including maybe skipping the C++ part alltogether).

> Why not to just use Rust as their system language.

Rust has been evaluated, but discarded (mainly, iirc) due to it's approach (or lack thereof) for OOP. Also, the whole "we want to make things ourselves" thing.

It should be noted that most of the SerenityOS umbrella is written in modern C++ (modern enough that you may very well need to compile a compiler to build the project). Rust and C++ can interoperate, but the process isn't exactly user friendly.

The goal of the language, as I understand it, was to make working on the rest of the Serenity projects more pleasant and safe. Even modern C++ has some annoying footguns but rewriting the entire system simply wasn't an option.

As such, jakt compiles to C++, specially C++ that interoperates with a lot of SerenityOS code, and doing that from Rust code would probably be a much worse experience.

Rewriting it in jakt is now a thing!

What? From my knowledge Jakt is written in C++ and Jakt itself, not Rust.

Sure the first implementation was written in Rust but it was quickly replaced when Adreas took over the project.