java.lang.NullPointerException at org.hl7.fhir.r5.comparison.ProfileComparer.checkAddTypeUnion(ProfileComparer.java:601) at org.hl7.fhir.r5.comparison.ProfileComparer.unionTypes(ProfileComparer.java:537) at org.hl7.fhir.r5.comparison.ProfileComparer.compareElements(ProfileComparer.java:229) at org.hl7.fhir.r5.comparison.ProfileComparer.compareChildren(ProfileComparer.java:330) at org.hl7.fhir.r5.comparison.ProfileComparer.compareElements(ProfileComparer.java:246) at org.hl7.fhir.r5.comparison.ProfileComparer.compare(ProfileComparer.java:148) at org.hl7.fhir.r5.comparison.ComparisonSession.compare(ComparisonSession.java:97) at org.hl7.fhir.igtools.publisher.comparators.PreviousVersionComparator.finishChecks(PreviousVersionComparator.java:263) at org.hl7.fhir.igtools.publisher.Publisher.checkConformanceResources(Publisher.java:5085) at org.hl7.fhir.igtools.publisher.Publisher.loadConformance(Publisher.java:4954) at org.hl7.fhir.igtools.publisher.Publisher.createIg(Publisher.java:1067) at org.hl7.fhir.igtools.publisher.Publisher.execute(Publisher.java:897) at org.hl7.fhir.igtools.publisher.Publisher.main(Publisher.java:10598) at org.hl7.fhir.igtools.publisher.utils.PublicationProcess.runBuild(PublicationProcess.java:373) at org.hl7.fhir.igtools.publisher.utils.PublicationProcess.doPublish(PublicationProcess.java:259) at org.hl7.fhir.igtools.publisher.utils.PublicationProcess.publishInner(PublicationProcess.java:208) at org.hl7.fhir.igtools.publisher.utils.PublicationProcess.publish(PublicationProcess.java:64) at org.hl7.fhir.igtools.publisher.Publisher.main(Publisher.java:10360)