[Bug c++/95180] New: Failure to reject invalid code with attempted redefinition of symbol with different linkage

[gabravier at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95180

            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=c++20 -pedantic-errors` so I'll
assume this is a bug, rather than some part of GNU C++. Furthermore, GCC
correctly rejects 

void g(int i)
{
  int i;
}

, so this really looks like a bug to me.