[Bug c++/126421] New: Accepts mismatched thread_local

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126421

            Bug ID: 126421
           Summary: Accepts mismatched thread_local
           Product: gcc
           Version: 17.0
            Status: UNCONFIRMED
          Keywords: accepts-invalid
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---

Take:
```
int foo9_decl;
int foo9() {
  extern thread_local int foo9_decl;
  return foo9_decl;
}

void test_foo9() {
  foo9();
}
```
This should be rejected but currently it is not.