java.lang.NullPointerException: Cannot invoke "java.util.List.iterator()" because "lc" is null
	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compareDiffChildren(StructureDefinitionComparer.java:553)
	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compareDiff(StructureDefinitionComparer.java:475)
	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compareDiffChildren(StructureDefinitionComparer.java:581)
	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compareDiff(StructureDefinitionComparer.java:475)
	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compare(StructureDefinitionComparer.java:179)
	at org.hl7.fhir.r5.comparison.ComparisonSession.compare(ComparisonSession.java:107)
	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.checkAddTypeUnion(StructureDefinitionComparer.java:966)
	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.unionTypes(StructureDefinitionComparer.java:903)
	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compareElements(StructureDefinitionComparer.java:278)
	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compareChildren(StructureDefinitionComparer.java:382)
	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compareElements(StructureDefinitionComparer.java:295)
	at org.hl7.fhir.r5.comparison.StructureDefinitionComparer.compare(StructureDefinitionComparer.java:173)
	at org.hl7.fhir.r5.comparison.ComparisonSession.compare(ComparisonSession.java:107)
	at org.hl7.fhir.igtools.publisher.comparators.IpaComparator.finishChecks(IpaComparator.java:232)
	at org.hl7.fhir.igtools.publisher.Publisher.checkConformanceResources(Publisher.java:6573)
	at org.hl7.fhir.igtools.publisher.Publisher.loadConformance2(Publisher.java:6377)
	at org.hl7.fhir.igtools.publisher.Publisher.createIg(Publisher.java:1224)
	at org.hl7.fhir.igtools.publisher.Publisher.execute(Publisher.java:1083)
	at org.hl7.fhir.igtools.publisher.Publisher.main(Publisher.java:15393)