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From: "gabravier at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/95180] New: Failure to reject invalid code with attempted
 redefinition of symbol with different linkage
Date: Sun, 17 May 2020 20:36:25 +0000
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X-Bugzilla-Product: gcc
X-Bugzilla-Component: c++
X-Bugzilla-Version: 11.0
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D95180

            Bug ID: 95180
           Summary: Failure to reject invalid code with attempted
                    redefinition of symbol with different linkage
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gabravier at gmail dot com
  Target Milestone: ---

void g(int i)
{
  extern int i;
}

`extern int i;` redefines the `i` parameter and is thus invalid (Clang also
rejects it). This is not warned about by `-std=3Dc++20 -pedantic-errors` so=
 I'll
assume this is a bug, rather than some part of GNU C++. Furthermore, GCC
correctly rejects=20

void g(int i)
{
  int i;
}

, so this really looks like a bug to me.=