Generic method returning generic interface in Delphi 2010

Question

Given the code below, wich is a very trimmed down version of the actual code, I get the following error:

[DCC Error] Unit3.pas(31): E2010 Incompatible types: \'IXL

Answer 1

With three minor modification (IInterface, FindAll with "S: class" [Thanks Mason] and the typecasts in FindAll) I got it compiling.

Full code:

unit Unit16;

interface

uses
  Generics.Collections;

type
  IXList = interface
  end;

  TXList = class(TList, IInterface, IXList)
  protected
    FRefCount: Integer;
    function QueryInterface(const IID: TGUID; out Obj): HResult; stdcall;
    function _AddRef: Integer; stdcall;
    function _Release: Integer; stdcall;
  public
    function Find: IXList;
    function FindAll: IXList;
  end;

implementation
uses Windows;

function TXList.Find: IXList;
begin
  Result := TXList.Create;
end;

function TXList.FindAll: IXList;
begin
  Result := IXList(IUnknown(TXList.Create));
end;

function TXList.QueryInterface(const IID: TGUID; out Obj): HResult;
begin
  Result := E_NoInterface;
end;

function TXList._AddRef: Integer;
begin
  InterlockedIncrement(FRefCount);
end;

function TXList._Release: Integer;
begin
  InterlockedDecrement(FRefCount);
  if FRefCount = 0 then Self.Destroy;
end;

end.