When exploring Go interfaces, I noticed that it was not as simple to determine which Types are implementing a specific interface. This occurred when I was trying to find a
Reader implementation for my little unix cat program.
I ended up finding the guru tool and this helped me find my way.
guru tool describes itself as a:
a tool for answering questions about Go source code.
It has some documentation but I think that the tool itself is intended more towards editors than on a terminal.
guru is quite a neat tool which allows integrating editors to have code navigation/exploration functionality. I notice that much of Go is contained in these small utilities and that it just takes a bit of searching to find them.