[Ada] Parent_Unit_Names and unit renaming declarations

[Arnaud Charlet]

If the parent unit name that appears in a with_clause denotes a renaming
declaration, the parser has already retrieved the renamed unit in order to
obtain the real library unit denoted by the clause. If the parent unit nsme
is a simple name we set its entity to be the renamed unit. If the parent unit
name is itself a child unit, the prefix of its name is irrelevant to subsequent
visibility, and we replace it directly with a reference to the renamed unit.

Compiling and executing main.adb below must yield;

   P2
   P2.Sub
   P2
   P2.Sub

-----
with Root.P1;
with Root.P1.Sub;
with P3;
procedure Main is
begin
   Root.P1.Proc;
   Root.P1.Sub.Proc;
   P3.Run;
end Main;
---
package Root is
   procedure proc;
end Root;
---
package P2 is
   procedure Proc;
end P2;
---
package P3 is
  procedure Run;
end P3;
---
with P2;
package Root.P1 renames P2;
---
with Ada.Text_IO;
package body P2.Sub is

   procedure Proc is
   begin
      Ada.Text_IO.Put_Line ("P2.Sub");
   end Proc;

end P2.Sub;
---
package P2.Sub is
  procedure Proc;
end P2.Sub;
---
with Ada.Text_IO;
package body P2 is

  procedure Proc is
  begin
    Ada.Text_IO.Put_Line ("P2");
  end Proc;
end P2;
---
with Root.P1;
with Root.P1.Sub;
package body P3 is

  procedure Run is
  begin
    Root.P1.Proc;
    Root.P1.Sub.Proc;
  end Run;

end P3;
---
with Ada.Text_IO;
package body Root is

  procedure Proc is
  begin
    Ada.Text_IO.Put_Line ("Root");
  end Proc;

end Root;
---

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

2010-10-22  Ed Schonberg  <schonberg@adacore.com>

	* sem_ch10.adb (Analyze_With_Clause): If the parent_unit_name in a with
	clause is a child unit that denotes a renaming, replace the
	parent_unit_name with a reference to the renamed unit, because the
	prefix is irrelevant to subsequent visibility..

-------------- next part --------------
Index: sem_ch10.adb
===================================================================
--- sem_ch10.adb	(revision 165803)
+++ sem_ch10.adb	(working copy)
@@ -2556,6 +2556,22 @@ package body Sem_Ch10 is
          Par_Name := Scope (E_Name);
          while Nkind (Pref) = N_Selected_Component loop
             Change_Selected_Component_To_Expanded_Name (Pref);
+
+            if Present (Entity (Selector_Name (Pref)))
+              and then
+                Present (Renamed_Entity (Entity (Selector_Name (Pref))))
+              and then Entity (Selector_Name (Pref)) /= Par_Name
+            then
+
+            --  The prefix is a child unit that denotes a renaming
+            --  declaration. Replace the prefix directly with the renamed
+            --  unit, because the rest of the prefix is irrelevant to the
+            --  visibility of the real unit.
+
+               Rewrite (Pref, New_Occurrence_Of (Par_Name, Sloc (Pref)));
+               exit;
+            end if;
+
             Set_Entity_With_Style_Check (Pref, Par_Name);
 
             Generate_Reference (Par_Name, Pref);