Can not jump to definition of unused extended module

[jurgenvinju]

Describe the bug

• Define an empty module A
• import ParseTree;
• hover and CMD+click will not work because there is "unused extend"

The issue is that of usability. I want to explore the ParseTree module before I start using it and at the moment in VScode the only way to get to the code of library modules is by following the links.

[PaulKlint]

The only solution is to not generate this message. Is that desirable? I am not so sure about this. Or is there another solution viable?

[jurgenvinju]

I think someone is filtering references for extended modules with warnings or errors; maybe just not filter the references if the module name is resolved but not used?