anchor.diff:        if (element == null) {
           AstNode parent = node.parent;
           if (parent is Annotation) {
  -          _resolver.errorReporter.reportErrorForNode(
  +          _errorReporter.reportErrorForNode(
                 CompileTimeErrorCode.UNDEFINED_ANNOTATION,
                 parent,
                 [identifier.name]);
           } else {
  -          _resolver.errorReporter.reportErrorForNode(
  +          _errorReporter.reportErrorForNode(
                 StaticTypeWarningCode.UNDEFINED_PREFIXED_NAME,
                 identifier,
                 [identifier.name, prefixElement.name]);
  
positive.code:           propertyName.staticElement = element;
            _checkForStaticAccessToInstanceMember(propertyName, element);
          } else {
            _resolver.errorReporter.reportErrorForNode(
              CompileTimeErrorCode.UNDEFINED_EXTENSION_SETTER,
              propertyName,
              [memberName, extension.name],
  
negative.code:               ClassElementImpl receiverSuperClass =
                    staticType.element.supertype.element;
                if (!receiverSuperClass.hasNoSuchMethod) {
                  _errorReporter.reportErrorForNode(
                    CompileTimeErrorCode.ABSTRACT_SUPER_MEMBER_REFERENCE,
                    propertyName,
                    [element.kind.displayName, propertyName.name],
                  );
                }
              } else {
                _errorReporter.reportErrorForNode(
                  StaticTypeWarningCode.UNDEFINED_SUPER_GETTER,
                  propertyName,
                  [propertyName.name, staticType],
  