Three Rascal Exceptions

[mhow2]

Already discussed with @tdegueul , I have observed those 3 exceptions while analyzing XWiki.

ERROR [RascalMetricProvider (Changed methods)] (05:07:40): metric threw an exception: |std:///Set.rsc|:313,0: EmptySet() at |std:///Set.rsc|(6603,397,<313,0>,<330,54>) ERROR [RascalMetricProvider (Number of changes)] (05:07:47): metric threw an exception: |std:///Set.rsc|:313,0: EmptySet() at |std:///Set.rsc|(6603,397,<313,0>,<330,54>) ERROR [RascalMetricProvider (Number of breaking changes)] (05:10:12): metric threw an exception: |std:///Set.rsc|:313,0: EmptySet() at |std:///Set.rsc|(6603,397,<313,0>,<330,54>)

metric-pf.log