[Bug ada/107536] New: [12 regression] Wrong 'not referenced' warning on renamed variable

["simon at pushface dot org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107536

            Bug ID: 107536
           Summary: [12 regression] Wrong 'not referenced' warning on
                    renamed variable
           Product: gcc
           Version: 12.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ada
          Assignee: unassigned at gcc dot gnu.org
          Reporter: simon at pushface dot org
  Target Milestone: ---

Created attachment 53834
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53834&action=edit
Demonstrator

If a record has aspect Volatile_Full_Access, a renaming of one of the record’s
components will be reported as unreferenced even though it plainly is.

$ gnatmake -gnatwa -c -u -f renaming.adb -gnatl
gcc -c -gnatwa -gnatl renaming.adb

GNAT 12.2.0
Copyright 1992-2022, Free Software Foundation, Inc.


Compiling: renaming.adb
Source file time stamp: 2022-11-05 16:48:11
Compiled at: 2022-11-05 16:50:40

     1. procedure Renaming is
     2.
     3.    type T is record
     4.       Item : Integer;
     5.    end record;
     6.    A_T : T;
     7.    Item : Integer renames A_T.Item;
     8.
     9.    type VFA_T is record
    10.       Item : Integer;
    11.    end record
    12.    with Volatile_Full_Access;
    13.    A_VFA_T : VFA_T;
    14.    VFA_Item : Integer renames A_VFA_T.Item;
           |
        >>> warning: renamed variable "VFA_Item" is not referenced [-gnatwu]

    15.
    16. begin
    17.    Item := 42;
    18.    VFA_Item := 42;
    19. end Renaming;

 19 lines: No errors, 1 warning

This is also present on 12.1.0.