[fpc-pascal] Memory leak on TFPGInterfacedObjectList

[Joao Morais]

Hello list. Whenever I add interfaced objects to a 
TFPGInterfacedObjectList, those objects apparently add two references, 
while release only one when the list is cleaned or destroyed.

The following code shows:

==========>>>==========
$ /tmp/project1
just before vl.add(v1)..: 1
just after vl.add(v1)...: 3
after destroy the list..: 2
Heap dump by heaptrc unit
9 memory blocks allocated : 773/784
8 memory blocks freed     : 757/768
1 unfreed memory blocks : 16
True heap size : 622592 (32 used in System startup)
True free heap : 622464
Should be : 622480
Call trace for block $000F31E0 size 16
   $000210DF  _P$PROJECT1_finalize_implicit,  of 
/private/tmp//tmp/project1.lpr
   $00021EF1  _P$PROJECT1_finalize_implicit,  of 
/private/tmp//tmp/project1.lpr
   $00020E4F  _P$PROJECT1_finalize_implicit,  of 
/private/tmp//tmp/project1.lpr
==========<<<==========

The code:

==========>>>==========
program Project1;

uses
   heaptrc, fgl, sysutils;

type
   i1 = interface(iinterface)
     function ref: integer;
   end;

   tl = specialize TFPGInterfacedObjectList<i1>;

   t1 = class(TInterfacedObject, i1)
   public
     function ref: integer;
   end;

var
   v1: i1;
   vl: tl;

function t1.ref: integer;
begin
   result := frefcount;
end;

begin
   v1 := t1.create;
   vl := tl.create;
   try
     writeln('just before vl.add(v1)..: ', v1.ref);
     vl.add(v1);
     writeln('just after vl.add(v1)...: ', v1.ref);
     vl.Clear;
   finally
     freeandnil(vl);
   end;
   writeln('after destroy the list..: ', v1.ref);
end.
==========<<<==========

Am I missing something?

Thanks!