Just noticed this little broken gem...
The setup is two modules (module-1, module-2) where module-1 includes an
interface, and module2 includes an implementation.
If you add a method definition to the interface, then use the intention
to implement the interface, IDEA will tell you theres no classes which
can implement the method.
IDEA is successfully finding the class from its module dependencies to
give a hyperlink for existing methods.