Undocumented Delphi 8 Language changes

Before Delphi 8, the following code does not compile.

In Delphi 8, the following code compiles. Something to take note of if you're backporting Delphi 8 code to previous Delphi versions.

type
  TA = record
   F: Byte;
  end;

var
 O: TObject;
 A: TA;
begin
  O := A;
end.

Quiz

1. Before Delphi 8, what error message does the compiler emit?