The majority of the code in the project is already written in Rust. If we're judging Rust based on its acceptance in Fuchsia for some weird reason, it's doing very well. Doing the best, in fact.

I'm sorry your comment is in the grey here. I think if you'd just stuck to: "If we're judging Rust based on its acceptance in Fuchsia for some weird reason, it's doing very well.", It'd have been better received.

Calling it the "majority" or "doing the best" is probably coming off as disingenuously impling "most significant". Sloc dosn't meet anyone's idea of that.

That's probably in part demand driven? I.e., there's little need for rust to be supported officially for end users.

Moreover, C is supported for end users, and if C is supported then Rust is de facto supported though C bindings, which Rust understands natively.

Someone will have the fun of writing those wrappers, because Google won't do it.

Likewise a future Fuchsia Studio won't support templates, debugging, or OS libraries written in Rust.

And the Fuchsia team most likely won't prioritize toolchain bugs related to Rust.

This is the biggest difference between using an official SDK language and guest languages.

Rust doesn't have a stable ABI, so it's sensible to always go through C bindings anyway. The other things you mention are just a matter of what their future Fuchsia Studio chooses to support.