title: Delphi : Variable used in the "for In" cannot be assigned!
body: <p>Why is the assignment in the for...in loop disallowed by the compiler?</p>
  
  <pre><code>procedure TForm1.Button1Click(Sender: TObject);
  Var
    ars : Array [0..10] of Integer;
    s : Integer;
    ct : Integer;
  begin
    ct := 0;
    for s in ars do
    Begin
      s := ct; // Does not compile!
      Inc(ct);
    End;
  End;
  </code></pre>