Ah, yeah. Sounds like a problem for a (static) callgraph analyzer (and probably visualizer). I haven't played with the Go callgraph tooling at all, I'm guessing the static analysis is unsatisfactory?

Definitely not a panacea, but this sometimes helps: change a datatype and/or manually change a field name near the area being worked on, such that the compiler fails out at places that stuff gets used. Then just keep fixing each compile problem until you've visited all the affected sites.