Delphi的接口陷阱

Delphi的接口陷阱(2)     function Do: Boolean;
end;

TC1 = Class
    ATT1: Integer;
end;

TC2 = Class(TC1, I1)
    ATT2: Integer;
    function Do: Boolean;
end;

Intf1: I1;

OBJ1: TC!;

OBJ2: TC2;

OBJ2 := TC2.Create;
OBJ1 := OBJ2.
I1(OBJ2).DO;正确。