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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/16186] gcc should have an option to warn about enumerations
 with duplicate values
Date: Mon, 13 Mar 2023 13:44:53 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D16186

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to trashyankes from comment #7)
> Should be way to disable/enable this warning per `enum`?
> Like:
>=20
> ```
> enum [[gnu::enum_unique]] X
> {
>   I =3D 1,
>   J =3D 2,
> };
>=20
> enum [[gnu::enum_not_unique]] Y
> {
>   K =3D 1,
>   L =3D 1,
> };
>=20
> ```

No, it should warn solely if enumerator gets implicitly assigned value of s=
ome
other enumerator.  After all, the clang wording also mentions that:
element 'D' has been implicitly assigned 5 which another element has been
assigned [-Wduplicate-enum]
If there is =3D value for it, we should never warn, that is most likely
completely intentional.
Of course, we should use better wording, because we should talk about
enumerators, not elements...=