Online PHP editor | output for oJBnZ

Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6: Fatal error: Uncaught TypeError: array_keys(): Argument #1 ($array) must be of type array, string given in /in/oJBnZ:3 Stack trace: #0 /in/oJBnZ(3): array_keys('foo', Array, true) #1 {main} thrown in /in/oJBnZ on line 3
Process exited with code 255.
Output for 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33: Warning: array_keys() expects parameter 1 to be array, string given in /in/oJBnZ on line 3 Warning: count(): Parameter must be an array or an object that implements Countable in /in/oJBnZ on line 3 int(0)
Output for 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.7 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.33: Warning: array_keys() expects parameter 1 to be array, string given in /in/oJBnZ on line 3 int(0)
Output for 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17: Warning: array_keys(): The first argument should be an array in /in/oJBnZ on line 3 int(0)
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9: Warning: Wrong parameter count for array_keys() in /in/oJBnZ on line 3 int(0)