Citation needed.

From what I understand there is no Rust being used internally at Google (apart from perhaps individual engineers tinkering with it just for fun).

There is no support for it from the build tools, so anything more than just messing about on your own machine won't work at Google: no libraries, no way to compile it, no way to test it, no way to deploy it, and no way to monitor it.

I do not know about internally, fuschia apparently has major parts written in Rust.

And Chromium's crosvm. Rust is a perfect fit for that particular task (writing a VMM).

I would be surprised if there was widespread usage of it, though. Rust chose a whole different set of tradeoffs than Go.