gistfile1.txt

malets@mac:~$ cat 2.cc
constexpr int f() {
  int x[] = {0};
  return x[1];
}

int main(void) {
  return f();
}
malets@mac:~$ clang++ -std=c++14 2.cc
2.cc:3:10: warning: array index 1 is past the end of the array (which contains 1 element) [-Warray-bounds]
  return x[1];
         ^ ~
2.cc:2:3: note: array 'x' declared here
  int x[] = {0};
  ^
1 warning generated.
malets@mac:~$ ./a.out
malets@mac:~$ echo $?
240
malets@mac:~$