Legality: formal packages with controlled types

[Simon Wright <simon@pushface.org>]

The code below fails on OA 7.2 with

bug.ada: Error: line 21 col 42 LRM:3.9.1(3), The accessibility level
       of a record extension shall not exceed that of its parent; this
       also applies in a generic instantiation (In instance of generic
       base at bug.ada: line 7 col 7)

and similar code fails similarly on OA 7.2.1 and AdaMULTI v3.1 I'm
told.  Presumably they all share a front end.

The code compiles OK if Base.Container isn't derived from Controlled.

Is it really the case that it's legal to instantiate a generic package
with a package that contains a controlled type but illegal to
instantiate a generic subprogram?

========================================================
with ada.finalization;
generic
	type item is private;
package base is
	type container is tagged private;
private
	type container is new ada.finalization.controlled with record
		the_item : item;
	end record;
end base;

with base;
generic
	type item is private;
	with package New_Base is new base (item);  -- <==== ok
package Generic_package is end Generic_package;

with base;
generic
	type item is private;
	with package new_base is new base (item);  -- <==== failure
procedure Generic_Procedure;

procedure generic_procedure is
begin
	null;
end generic_procedure;