anchor.diff:    final Map<String, int> refCountPerResource = {};
     final Map<String, String> localNames = {};
     final Map<String, List<js.Property>> propertiesPerResource = {};
  -  int _index;
  -  int _hashCode;
  +  late final int index;
  +  @override
  +  late final int hashCode = Hashing.objectsHash(key);
   
     Holder(this.key);
   
     int refCount(String resource) {
       assert(refCountPerResource.containsKey(resource));
  -    return refCountPerResource[resource];
  +    return refCountPerResource[resource]!;
     }
   
     String localName(String resource) {
       assert(localNames.containsKey(resource));
  -    return localNames[resource];
  +    return localNames[resource]!;
     }
   
     void setLocalName(String resource, String name) {
  
positive.code: 
    /// Returns a global object for a given [Object] based on the
    /// [DeferredHolderExpressionKind].
    Holder kindToHolder(DeferredHolderExpressionKind kind, Object data) {
      switch (kind) {
        case DeferredHolderExpressionKind.globalObjectForInterceptors:
          return globalObjectForInterceptors;
        case DeferredHolderExpressionKind.globalObjectForClass:
          return globalObjectForClass(data);
        case DeferredHolderExpressionKind.globalObjectForMember:
          return globalObjectForMember(data);
        case DeferredHolderExpressionKind.globalObjectForConstant:
          return globalObjectForConstant(data);
        case DeferredHolderExpressionKind.globalObjectForStaticState:
          return globalObjectForStaticState;
      }
      throw UnsupportedError("Unreachable");
    }
  
    /// Finalizes [DeferredHolderParameter]s.
  
negative.code: /// [DeferredHolderResource]s, [DeferredHolderResourceExpression]s.
  class DeferredHolderExpressionFinalizerImpl
      implements DeferredHolderExpressionFinalizer {
    late final _DeferredHolderExpressionCollectorVisitor _visitor;
    final Map<String, List<DeferredHolderExpression>> holderReferences = {};
    final List<DeferredHolderParameter> holderParameters = [];
    final List<DeferredHolderResource> holderResources = [];
  