This code in a GUI application compiles and runs:

procedure TForm1.Button1Click(Sender: TObject);
begin
  Self := TForm1.Create(Owner);
end;

(tested with Delphi 6 and 2009)

• why is Self writeable and not read-only?
• in which situations could this be useful?

Edit:

• is this also possible in Delphi Prism? (I think yes it is, see here)

Update: Delphi applications/libraries which make use of Self assignment:

• python4delphi