Why this error, value not in range of subtype of "Standard.Integer"?

["Nasser M. Abbasi" <nma@12000.org>]

experts;

If I write this, I get an error as show: (notice the B
matrix declaration, that is where the problem is)

-------------- this does not work ------
with Ada.Numerics.Real_Arrays;  use Ada.Numerics.Real_Arrays;

procedure foo2 is
     A : constant Real_Matrix :=
              (( 1.0,  2.0,  3.0),
               ( 4.0,  5.0,  6.0),
               ( 7.0,  8.0,  9.0));
     B : Real_Matrix(1 .. 3,1 .. 3);  -- this is the problem
begin

     FOR I in A'range(1) LOOP
           FOR J in A'range(2) LOOP
               B(I,J) := 1.0;
           END LOOP;
     END LOOP;
     
end foo2;
-------------------------------

>gnatmake foo2.adb
gcc-4.6 -c foo2.adb
foo2.adb:13:17: warning: value not in range of subtype of "Standard.Integer" defined at line 8
foo2.adb:13:17: warning: "Constraint_Error" will be raised at run time
foo2.adb:13:19: warning: value not in range of subtype of "Standard.Integer" defined at line 8
foo2.adb:13:19: warning: "Constraint_Error" will be raised at run time
gnatbind -x foo2.ali
gnatlink foo2.ali

But if I change the declaration of B from
      B : Real_Matrix(1 .. 3,1 .. 3);
to
      B : Real_Matrix(A'RANGE(1), A'RANGE(2));

then Ada is happy now.

Isn't A'RANGE(1) the same as 1 .. 3 and A'RANGE(2) the same as 1 .. 3?
or is this one of those typing issues?

---------------------------------------------
with Ada.Numerics.Real_Arrays;  use Ada.Numerics.Real_Arrays;

procedure foo1 is
     A : constant Real_Matrix :=
              (( 1.0,  2.0,  3.0),
               ( 4.0,  5.0,  6.0),
               ( 7.0,  8.0,  9.0));
     B : Real_Matrix(A'RANGE(1), A'RANGE(2));
begin
     FOR I in A'range(1) LOOP
           FOR J in A'range(2) LOOP
               B(I,J) := 1.0;
           END LOOP;
     END LOOP;
         
end foo1;
------------------------------

(one thing I like about Ada, is that once the program compiles clean,
then it runs fine !)

thanks
--Nasser