go get golang.org/x/tools/cmd/oracle package golang.org/x/tools/cmd/oracle: cannot find package "golang.org/x/tools/cmd/oracle" in any of: /usr/local/Cellar/go/1.8/libexec/src/golang.org/x/tools/cmd/oracle (from $GOROOT) /Users/me/go_vendor/src/golang.org/x/tools/cmd/oracle (from $GOPATH)
The reason why this error occured
At the moment, this tool has been replaced to tools/cmd/guru godoc.org
So, you just get tools/cmd/guru, this problem can be solved.
go get golang.org/x/tools/cmd/oracle