"Automatically figuring out which parent objects the class you're subclassing derives from" AFAIK this is a language limitation, there is no way in a Rust macr

"Automatically figuring out which parent objects the class you're subclassing derives from" AFAIK this is a language limitation, there is no way in a Rust macro to take a type and get all the traits that are implemented for that type. It would need some kind of reflection API. Maybe someone could try it with this crate? https://crates.io/crates/reflect https://crates.io/crates/reflect "Helpers for properties and signals" There are some open issues for this: https://github.com/gtk-rs/gtk-rs-core/issues/27 https://github.com/gtk-rs/gtk-rs-core/issues/27 https://github.com/gtk-rs/gtk-rs-core/issues/214 https://github.com/gtk-rs/gtk-rs-core/issues/214 "A flat list of methods, instead of the public/imp split" You can already do this in your code and use "pub fn" and "fn" like normal. "I feel like I had a difficult time figuring out how to share state between widgets. You end up with lots of OnceCell, Rc, and RefCell, and it quickly becomes confusing," I think you are supposed to use bind_property and the gtk::Expression objects to do data binding, though that part is not so convenient to use from C or Rust either.