How to import a package from a subpackage?

Question

go

There is a main package with a module subpackage.
That is, in the project folder there are files
main.go and module/module.go
How do I understand how to import a module from main, but vice versa?
in module.go I write
import "../main" does not work

Answer 1

main cannot be imported

Answer 2

Found a solution:
make another subpackage
a function from this subpackage can be used from in the main module, and in another subpackage.

Answer 3

Canvas https://habrahabr.ru/post/111308/