I don’t see much, if any, generated Go code at Google. Not to say that it doesn’t happen but it’s not on my radar.
Here is an example: https://github.com/google/gvisor - https://github.com/google/gvisor/tree/master/tools/go_generi...
It was useful enough that someone made a standalone package: https://github.com/mmatczuk/go_generics
Kubernetes makes heavy use of generated code, as workaround for lack of generics.
They even gave a FOSDEM talk about this, with a very interesting title.
https://fosdem.org/2019/schedule/event/kubernetesclusterfuck...
The lack of generics just severely restricts the expressiveness of the type system.
I think the best way to work around this is use of code generation, which is a great tool for internal, controlled environments, but very cumbersome for open source libraries.