Re: Visibility of package parameters in child packages

[Andrea Taverna <a.tavs@hotmail.it>]

On 15 Dic, 22:00, Georg Bauhaus <rm.dash-bauh...@futureapps.de> wrote:
> Andrea Taverna schrieb:
>
>
>
> > generic
> >    with package P is new Q (<>);
> >    use P;
> > package Parent is
> > ...
> > end Parent;
>
> > generic
> > Parent.Child is
> > ...
> > end Parent.Child;
>
> > I can see P declarations inside Parent, but in Child I need to prefix
> > everything with 'P.', even if I add a use-clause.
> > This happens with gnat-4.3.0 .
> > Is it normal? How can I "use" P inside Child?
>
> generic
> Parent.Child is
>   use P;
> end Parent.Child;

I compiled the following
-----%<-----%<-----%<-----%<-----%<
-- SIGNATURE PACKAGE
generic
   type T is private;
   with function F(X : T) return T;
package Q is end Q;

-- PARENT
with Q;
with Ada.Text_IO;
 generic
    with package P is new Q(<>);
    use P;
 package Parent is

    procedure A (X : T);
 end Parent;

 package body Parent is

    procedure A (X : T) is
       C : T := F(X);
    begin
       Ada.Text_IO("Hello");
    end A;

 end Parent;

-- CHILD
 generic
 package Parent.Child is
    use P;
    function B(X : T) return T;
 end Parent.Child;

 package body Parent.Child is

function B(X : T) return T is
   use P;
       D : T := F(X);
    begin
       return F(D);
    end B;
end Parent.Child;

-- INSTANTIATION
 with Parent.Child;
 with Q;

 procedure Main is
    function Incf(X : Integer) return Integer is begin  return X + 1;
end Incf;
    package R is new Q(Integer, Incf);
    package Par is new Parent(R);
    package Ch is new Par.Child;
 begin
    null;
 end Main;
-----%<-----%<-----%<-----%<-----%<

and the compiler replied

-----%<-----%<-----%<-----%<-----%<
]# gnatmake main.adb
gcc -c main.adb
main.adb:9:05: instantiation error at parent-child.adb:6
main.adb:9:05: "F" is not visible (more references follow)
main.adb:9:05: instantiation error at parent-child.adb:6
main.adb:9:05: non-visible declaration at q.ads:3
gnatmake: "main.adb" compilation error
-----%<-----%<-----%<-----%<-----%<

Am I missing something?