Renaming an abstract function

["Nick Roberts" <nickroberts@adaos.worldonline.co.uk>]

When given the program:

   package Test1 is
      type T is abstract tagged limited private;
      function P (X, Y: in T) return T is abstract;
      function "*" (A, B: in T) return T renames P; -- error line
   private
      type T is abstract tagged limited null record;
   end;

GNAT 3.12p on Windows 95 returns the error message:

   function that returns abstract type must be abstract

Is this a bug in: (a) GNAT; (b) the RM95; or (c) my brain?

Full detailed explanation welcome (if applicable).

--
Best wishes,
Nick Roberts