procedure TForm1.Button1Click(Sender: TObject);
var a: TA;
begin
  a.Something;
end;

TA = class(TObject)

TA = object

  TMonitor = class(TObject)
  private
    FHandle: HMONITOR;
    FMonitorNum: Integer;
    function GetLeft: Integer;
    function GetHeight: Integer;
    function GetTop: Integer;
    function GetWidth: Integer;
    function GetBoundsRect: TRect;
    function GetWorkareaRect: TRect;
    function GetPrimary: Boolean;
    function GetPixelsPerInch: Integer;

  Application.CreateForm(TForm1, Form1);
  ShowMessage(Form1.Monitor.GetTop);

Posted via ActualForum NNTP Server 1.5

  TMonitor = class(TObject)
  private
    FHandle: HMONITOR;
    FMonitorNum: Integer;
    function GetLeft: Integer;
    function GetHeight: Integer;
    function GetTop: Integer;
    function GetWidth: Integer;
    function GetBoundsRect: TRect;
    function GetWorkareaRect: TRect;
    function GetPrimary: Boolean;
    function GetPixelsPerInch: Integer;

  Application.CreateForm(TForm1, Form1);
  ShowMessage(Form1.Monitor.GetTop);

  Application.CreateForm(TForm1, Form1);
  ShowMessage(Form1.Monitor.Top);

...

type
  TMyClass = class
    procedure Test;
  end;

procedure TMyClass.Test;
begin
  WriteLn(Integer(Self));
end;

var
  mc: TMyClass;
begin
  mc := TMyClass.Create;
  mc.Free;

  mc.Test; // <-- что тут будет напечатано?
  ...

var
  mc: TMyClass;
begin
  mc.Test; // <-- что тут будет напечатано?

procedure TObject.Free;
begin
// under ARC, this method isn't actually called since the compiler translates
// the call to be a mere nil assignment to the instance variable, which then calls _InstClear
{$IFNDEF AUTOREFCOUNT}
  if Self <> nil then
    Destroy;
{$ENDIF}
end;

type 
  X = class
    метод;
  end;
var
  a, b : C;
...
begin
  a := C.Create();
...
  b := a; // Алиас
...
  FreeAndNil(a);
...
  b.метод; // Ничего не знает, что self теперь nil