[Bug c++/106729] New: Missing diagnostic for violation of 9.2.8.5

[whh8b at obs dot cr via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106729

            Bug ID: 106729
           Summary: Missing diagnostic for violation of 9.2.8.5
           Product: gcc
           Version: 12.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: whh8b at obs dot cr
  Target Milestone: ---

According to 9.2.8.5 of the C++ standard, the following code should produce a
diagnostic:

void testing() {
    return;
}

inline void testing();

int main() {
    return 0;
}

I can confirm that clang++ v 14.0.0 produces the proper diagnostic.