Failure when having rules on a package that only contains packages

[pkernevez]

I have a package named 'connectors' that contains several packages but not direct classes.
I want to have a rule like:

      DependencyRule common, connector;
  
      @Override
      public void defineRules() {
          common.mustNotUse(connector.allSubOf());
          connector.andAllSub().mayUse(common);
      }

But this test failed:

java.lang.AssertionError: 
Expected: Comply with rules
     but: 
NOT_EXISTING com.xxx.connector              There is a rule for this element, but it has not been found in the code.

But the package exists.
If I add a class directly in the package, the error disappears.

Do I miss something ?