Although you cannot execute a Go package if it does not include a main() function, you are still allowed to compile it and create an object file as follows:

$ go tool compile aPackage.go
$ ls -l aPackage.*
-rw-r--r--@ 1 mtsouk  staff   201 Dec 22 06:06 aPackage.go
-rw-r--r--  1 mtsouk  staff  4677 Dec 22 06:20 aPackage.o

If you successfully compile a Go package that you are developing using the preceding method, you must also make sure that you do not have any syntax errors in your code.