public override void VisitClassDeclaration(ClassDeclarationSyntax node)
            {
                IImmutableList <ITypeSymbol> baseTypes = SemanticModel.GetAllBaseTypeSymbols(node);
                bool isController = baseTypes.Any(t => t.Equals(KnownTypes.Controller));

                if (!isController)
                {
                    return;
                }

                IImmutableList <AttributeUsageInfo> attributeInfo = SemanticModel.GetAttributeInfo(node.AttributeLists);
                bool isVersioned = attributeInfo.Any(info => info.AttributeType.Equals(KnownTypes.ApiVersionAttribute));

                if (!isVersioned)
                {
                    return;
                }

                base.VisitClassDeclaration(node);
            }