I am not sure if it is a lack of clear documentation or dub just cannot do this at the moment.

I have struggled with a seemingly simple project (a root package with targetType "none" and a sub-package with targetType "executable"), and while I can make it build from command line, D language plugin for IntelliJ could not do auto-completion.

I have narrowed it down to the fact that auto-completion relies on the plugin's ability to ask dub for the locations of dependencies, which it does by calling dub describe. However, dub describe shows no dependencies, as the root package is just a group to hold a sub-package in it. If I make the root package to have the sub-package as its dependency - the build process fails as that is incompatible with targetType="none" (why?). And on top of that there is no obvious way to ask dub to list the sub-packages and then interrogate their dependencies one by one by calling dub describe :mysubpackage.

What could be done about this?

For the time being, I have updated a ticket in the dub-docs project: dlang/dub-docs#78
But perhaps a code change is required?