We didn't push to upstream now, we were invited to upstream in CRuby and we accepted the invitation. As for the Rust rewrite, we just started to work on the prototype, and no decision had been made. The ticket linked in this thread is me essentially asking the Ruby core devs for permission to do so. We wanted to give everyone an opportunity to chime in.

Not sure what to tell you. Things don't aways happen in the most optimal order in the real world, sometimes plans change, but I'm fairly confident that we can make this work well.