G.4.5 scalb code will not compile

In G.4.5 Overloading (page 574 in 2019), the sample code will not compile:

   constant half: ufixed (2 downto -2) := "00010"; -- 000.10
   variable two: ufixed (5 downto 0);
   variable someval: ufixed (5 downto -5);
begin
   two := scalb(half, 2); -- returns "00010.", or 2.0

This code will not compile because the two'length = 6 but half'length = 5