program project1; {$mode objfpc}{$H+} uses Classes, FGL; type TBaseClass = class (TObject) end; generic TFPGObjectListEx = class (specialize TFPGObjectList) function GetItemByID(AID: Integer): T; end; function TFPGObjectListEx.GetItemByID(AID: Integer): T; begin Result:=nil; //T(nil); end; begin end.