[Bug ada/123185] bogus component visibility error for class-wide type in generic package

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123185

--- Comment #5 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-15 branch has been updated by Eric Botcazou
<ebotcazou@gcc.gnu.org>:

https://gcc.gnu.org/g:1d26b1b37aac4bd898abf4425ffd6310d29db234

commit r15-10633-g1d26b1b37aac4bd898abf4425ffd6310d29db234
Author: Eric Botcazou <ebotcazou@adacore.com>
Date:   Mon Dec 22 18:50:59 2025 +0100

    Ada: Fix bogus component visibility error for class-wide type in generic

    The problem is that Analyze_Overloaded_Selected_Component does:

                --  If the prefix is a class-wide type, the visible components
                --  are those of the base type.

                if Is_Class_Wide_Type (T) then
                   T := Etype (T);
                end if;

    and Resolve_Selected_Component does:

                   --  The visible components of a class-wide type are those of
                   --  the root type.

                   if Is_Class_Wide_Type (T) then
                      T := Etype (T);
                   end if;

    while Analyze_Selected_Component does:

          --  For class-wide types, use the entity list of the root type

          if Is_Class_Wide_Type (Prefix_Type) then
             Type_To_Use := Root_Type (Prefix_Type);
          end if;

    when faced with a selected component.  So the 3rd goes to the root type,
the
    1st to the base type, and the 2nd wants to do like the 3rd but ends up
doing
    like the 1st!  This does not change anything for the class-wide type
itself,
    but does for its class-wide subtypes.  The correct processing is the 3rd.

    gcc/ada/
            PR ada/123185
            * sem_ch4.adb (Analyze_Overloaded_Selected_Component): Go to the
            root when the prefix has a class-wide type.
            * sem_res.adb (Resolve_Selected_Component): Likewise.

    gcc/testsuite/
            * gnat.dg/specs/class_wide1.ads: New test.