The Golang source code for the server code at google is built with this tool. The rules that accomplish this are rather complex due to their interactions with our C++ libraries, and predates the open source "Go" tool. The experience with the Google internal rules, motivated some of the choices in the "go" tool, I believe.

If you're interested, hanwen wrote a bunch rules with similar semantics as the internal rules, see https://github.com/google/bazel/tree/master/base_workspace/e... .

It would be nice to make these semantics match the external ones better, but it requires us to open up more tooling, so people won't need to write BUILD files.