Name mangling scheme preserves fully qualified package path. All goism sources live inside GOPATH (1), so nothing stops us from implementing a jump to Go definition.

For given `goism-foo/bar.baz` Emacs symbol, Go definition can be found in `GOPATH/src/foo/bar/` package. Exact location can be found by using existing Go tools (simple grep-like solution can work, too).

(1) It can change in future; see https://news.ycombinator.com/item?id=13368846 and even more relevant: https://github.com/golang/go/issues/17271