Just realized:

For me the most dangerous thing in ARC is the fact that you can never rely that a destructor gets called when you call Free. It is twice as dangerous because Embarcadero are advertising "debug mobile apps on Windows", which is impossible because ARC is missing on the Windows platform and therefore very different behaviour can occur.

Consider this code:

unit uFreeTest;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs, FMX.Layouts,
  FMX.Memo;

type
  TForm1 = class(TForm)
  public
    FSomeObject: TObject;
    procedure InitializeNewForm; override;
  end;

var
  Form1: TForm1;

implementation

{$R *.fmx}

type
  TMyObject = class
  public
    [weak] Console: TMemo;
    destructor Destroy; override;
  end;

destructor TMyObject.Destroy;
begin
  Console.Lines.Add('TMyObject.Destroy');

  inherited;
end;

{ TForm1 }

procedure TForm1.InitializeNewForm;
var
  Memo: TMemo;
  xObj: TMyObject;
begin
  inherited;

  Memo := TMemo.Create(Self);
  Memo.Parent := Self;
  Memo.Align := TAlignLayout.alClient;

  xObj := TMyObject.Create;
  try
    xObj.Console := Memo;
    FSomeObject := xObj;
  finally
    xObj.Free;
  end;
end;

end.


When running on Win32, the line 'TMyObject.Destroy' appears in the memo because the destructor is called normally.
In ARC (NextGen), the memo is clear. In more complex scenarios you basically never know if there is any reference left in your code. (Just image sending an object reference to a custom procedure which stores the reference somewhere.)
Hence you can basically never rely on the fact that the destructor gets called along with Free.

-> Yes, handle classes just like interfaces.
-> Therefore I am convinced that there shouldn't be any Free method in NextGen at all and the public destructor should be moved to the protected section (interfaces haven't got a free method either). Yes and Embarcadero should write NextGen for Win/Mac as well so that mobile projects behave correctly on all platforms.
-> And please, separate NextGen from Desktop development, they are just too different...

Please discuss :)
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