anchor.diff:    InboundReferences refs,
     BuildInboundEntry buildCallback,
   ) {
  -  final Iterable<InboundReference> elements = refs?.elements ?? [];
  +  final Iterable<InboundReference> elements = refs.elements ?? [];
     for (InboundReference element in elements) {
       // Could be a reference to an evaluate so this isn't known.
   
  
positive.code:         .toList();
    }
  
    Iterable<InboundReference> elements;
  }
  
  class InboundReference extends Response {
  
negative.code:     if (element.parentField.owner != null &&
          element.parentField.owner.name.contains('&')) continue;
  
      String? referenceName;
      String? owningAllocator; // Class or library that allocated.
      bool owningAllocatorIsAbstract = false;
  
      switch (element.parentField.runtimeType.toString()) {
        case 'ClassRef':
          final ClassRef classRef = element.classRef!;
          owningAllocator = classRef.name;
          // TODO(terry): Quick way to detect if class is probably abstract-
          // TODO(terry): Does it exist in the class list table?
  