Since the go directive in a module's go.mod file is a statement of the minimum Go version required to compile the packages in the module, it would be prudent to test that version of Go to ensure that nobody unknowingly introduces a language feature from a newer Go version.

Right now to do this you must list that Go version in your .travis.yml and keep it in sync with the version in your go.mod, which I think is error-prone.

I think it would be useful if there was a new alias to refer to the go directive in the go.mod file, such as:

go:
- stable
- module

It would choose the most recent patch release from that Go version.