"Shadowing" is a term we use as an approach to internal refactoring involving moving package structures where we keep a deprecated form of class to be moved in its old package and create a new one extending the old in the new location.

In the case of services though this causes problems the with ServiceRegistry and code that attempts to locate the service under the old role. Account for that use-case by adding an additional crawling (iterating) and possibly lazy xref building.