anchor.diff:          CompileTimeErrorCode.NON_CONSTANT_MAP_KEY_FROM_DEFERRED_LIBRARY,
         );
   
  -      if (mapUniqueKeys!.containsKey(keyValue)) {
  -        mapDuplicateKeyExpressions![keyExpression] = mapUniqueKeys![keyValue]!;
  +      var existingKey = config.uniqueKeys[keyValue];
  +      if (existingKey != null) {
  +        config.duplicateKeys[keyExpression] = existingKey;
         } else {
  -        mapUniqueKeys![keyValue] = keyExpression;
  +        config.uniqueKeys[keyValue] = keyExpression;
         }
       }
   
       if (valueValue != null) {
  -      if (!verifier._runtimeTypeMatch(valueValue, mapValueType!)) {
  +      if (!verifier._runtimeTypeMatch(valueValue, config.valueType)) {
           verifier._errorReporter.reportErrorForNode(
             CompileTimeErrorCode.MAP_VALUE_TYPE_NOT_ASSIGNABLE,
             valueExpression,
  -          [valueValue.type, mapValueType],
  +          [valueValue.type, config.valueType],
           );
         }
   
  
positive.code:   bool _validateListOrSetSpread(SpreadElement element, DartObjectImpl value) {
      var listValue = value.toListValue();
      var setValue = value.toSetValue();
  
      if (listValue == null && setValue == null) {
        if (value.isNull && _isNullableSpread(element)) {
          return true;
        }
        verifier._errorReporter.reportErrorForNode(
  
negative.code:       var verifier = _ConstLiteralVerifier(
          this,
          errorCode: CompileTimeErrorCode.NON_CONSTANT_LIST_ELEMENT,
          listElementType: elementType,
        );
        for (CollectionElement element in node.elements) {
  