System.Address'Size - not a static integer expression?

[vgodunko@vipmail.ru (Vadim Godunko)]

Hello,

I some type like this:

1  with System;
2
3  package A is
4
5     type T is private;
6
7  private
8
9     type T is record
10       P : System.Address := System.Null_Address;
11    end record;
12    for T'Size use System.Address'Size;
13
14 end A;

GNAT compiler report:
a.ads:12:33: static integer expression required here

Is this a compiler bug?

Thanks,
Vadim Godunko.