public override void visit(StructureRef obj, bool visitSubNodes)
        {
            bool errorDetected = true;

            Structure enclosingStructure = obj.Enclosing as Structure;
            if (enclosingStructure != null)
            {
                Structure structure = Dictionary.EFSSystem.FindType(enclosingStructure.NameSpace, obj.Name) as Structure;
                if (structure != null)
                {
                    if (structure.IsAbstract)
                    {
                        errorDetected = false;
                    }
                }
            }

            if (errorDetected)
            {
                obj.AddError("Referenced interface not found");
            }
        }