alt Hacker NewsThis particular compiler does require bootstrapping, and that's obviously what "the compiler" is referring to in that comment.
Building your compiler in another language doesn't help at all. In fact, it just makes it worse. Dogfooding C++20 in your compiler that isn't even built in C++ is obviously impossible.
It absolutely does not. There is no part of C++20 that requires the implementing compiler to be written in C++20.
My original point is that you can write a compiler for any language in any language.