[Ada] Spurious visibility error with entity in formal package.

[Arnaud Charlet <charlet at adacore dot com>]

This patch removes a spurious visibility error on a reference to a formal T
of a formal package, when T is declared as a formal derived type and there
is no corresponding actual for T in the formal package declaration, that is
to say it is covered by an (others => <>) clause.

Compiling c.adb must yield:

   c.adb:19:17: "Value_Type" is not a visible entity of "Bs"
   c.ads:10:40: "Value_Type" is not a visible entity of "Bs"

---
with A;
with B;
generic
   with package As is new  A (<>);
   with package Bs is new  B (Value_Type => As.Value_Type, others => <>);
package C is

   procedure Update_A_Value (Value : As.Value_Type);

   procedure Update_B_Value (Value : Bs.Value_Type);

   procedure Update_Object (Object : Bs.Derived_Object);

end C;
---
package body C is

   --------------------
   -- Update_A_Value --
   --------------------

   procedure Update_A_Value
     (Value : As.Value_Type)
   is
   begin
      null;
   end Update_A_Value;

   --------------------
   -- Update_B_Value --
   --------------------

   procedure Update_B_Value
     (Value : Bs.Value_Type)
   is
   begin
      null;
   end Update_B_Value;

   -------------------
   -- Update_Object --
   -------------------

   procedure Update_Object
     (Object : Bs.Derived_Object)
   is
   begin
      null;
   end Update_Object;

end C;
---
with Objects;

generic
   type Value_Type is limited private;
   type Derived_Object is new Objects.Object with private;
package B is
end B;
---
package Objects is

   type Object is tagged null record;

end Objects;

Tested on x86_64-pc-linux-gnu, committed on trunk

2017-04-27  Ed Schonberg  <schonberg@adacore.com>

	* sem_aux.adb (Is_Generic_Formal): Use original node to locate
	corresponding declaration, because formal derived types are
	rewritten as private extensions.

Attachment: difs
Description: Text document