AFAICT, QT has its own implementation of signals and slots (events and event handlers essentially) which is a pain for Rust's ownership model and it also has a

AFAICT, QT has its own implementation of signals and slots (events and event handlers essentially) which is a pain for Rust's ownership model and it also has a code generator that deals with some of C++'s limitations, making it harder to generate usable bindings. If that weren't enough, there is no native (clean) Rust way to do C++ inheritance which is another big pain.