I don't believe that the differences which you mentioned between those languages are relevant for kernel development. * Point one is a convenience/ease of use

I don't believe that the differences which you mentioned between those languages are relevant for kernel development. * Point one is a convenience/ease of use topic. Absent C++20 concepts or alternatively static asserts and enable_if, error messages will be harder to parse by the programmer. The one place where this may be relevant is for custom containers, but a kernel list for example wouldn't have to implement iterators and certainly doesn't need to follow the STL design which can cause hard to understand errors. * I don't understand what you mean when you say that Rust "solves" zero-cost abstractions, but C++ has had this goal for a very long time. * Exceptions would be disabled when doing kernel development. That being said, having exceptions in application development can be very convenient. C++ supports both, but std::optional and the like are not as elegant as in Rust.