Delphi const intf problem

program Project1;

{$APPTYPE CONSOLE}

uses
  SysUtils;

type TYoyop = class(TInterfacedObject)
  public
    constructor Create();
    destructor Destroy; override;
end;

{ TYoyop }

constructor TYoyop.Create;
begin
  Writeln('Created');
end;

destructor TYoyop.Destroy;
begin
  Writeln('Freed');
end;

procedure DoSmthg(const intf: IUnknown);
begin
  //
  Writeln('Some action');
end;

procedure Jojoba;
begin
  DoSmthg(TYoyop.Create);
end;

begin
  Jojoba;
  readln;
end.