The program as follows is ill-formed:
```
constexpr bool g() {
    int * p = nullptr;
    {
        int c = 0;
        p = &c;
    }
    return *p == 0; //indirection via dangling pointer
};

int main() {
    static_assert( g() );
}
```
but GCC erroneously accepts it, demo: https://gcc.godbolt.org/z/8xE7csGKo

The compiler must fail the program, see stackoverflow explanation: https://stackoverflow.com/a/69446660/7325599