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From: "marxin at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/107377] New: Warn about duplicate enum values?
Date: Mon, 24 Oct 2022 13:38:53 +0000
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X-Bugzilla-Version: 13.0
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D107377

            Bug ID: 107377
           Summary: Warn about duplicate enum values?
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
                CC: mpolacek at gcc dot gnu.org
  Target Milestone: ---

Noticed that while investigating PR107364:

enum processor_vendor
{
  VENDOR_INTEL =3D 1,
  VENDOR_AMD,
  VENDOR_ZHAOXIN,
  VENDOR_OTHER,
  VENDOR_CENTAUR,
  VENDOR_CYRIX,
  VENDOR_NSC,
  BUILTIN_VENDOR_MAX =3D VENDOR_OTHER,
  VENDOR_MAX
};

As one can see VENDOR_CENTAUR =3D=3D 5, but VENDOR_MAX is also =3D=3D 5 as
BUILTIN_VENDOR_MAX points to 4 and thus VENDOR_MAX =3D=3D 5.

Maybe we can warn about 2 enum values that have the same value and none of =
them
is defined with '=3D some_value'. What do you think?=