In Ada 95, the package Ada.Text_IO.Integer_IO is a subpackage of Text_IO.
This is for compatibility with Ada 83. In GNAT we make it a child package
to avoid loading the necessary code if Integer_IO is not instantiated. See
routine Rtsfind.Text_IO_Kludge for a description of how we patch up the
difference in semantics so that it is invisible to the Ada programmer.