These are not source modules I'm talking about. If it was only necessary to set $GOPATH to point to source modules then everything would be fine. The problem

These are not source modules I'm talking about. If it was only necessary to set $GOPATH to point to source modules then everything would be fine. The problem is that go requires that $GOPATH points to a project's source tree to be able to build it, if the project is organized to store other go source files in subdirectories. We aren't talking about packages or modules intended to be reused in other programs. We are talking about how source code trees are organized.