[Bug c++/109833] New: The value of constexpr anonymous union can be changed in runtime

[fchelnokov at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109833

            Bug ID: 109833
           Summary: The value of constexpr anonymous union can be changed
                    in runtime
           Product: gcc
           Version: 13.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: fchelnokov at gmail dot com
  Target Milestone: ---

The code as follows is accepted by GCC

constexpr static union {
  int k = 1;
};

int main() {
    k = 10;
}
static_assert(k == 1);


yet crashes in runtime, online demo: https://gcc.godbolt.org/z/r5h7eEjde