Online PHP editor | output for 0P3BK

Output for 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.34, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.34, 8.2.0 - 8.2.30, 8.3.0 - 8.3.30, 8.4.1 - 8.4.18, 8.5.0 - 8.5.3: Array ( [0] => 1 [1] => 2 [2] => 3 )
Output for 5.6.0 - 5.6.40: Catchable fatal error: Argument 1 passed to f() must be an instance of string, integer given, called in /in/0P3BK on line 3 and defined in /in/0P3BK on line 2
Process exited with code 255.
Output for 5.4.0 - 5.4.45, 5.5.0 - 5.5.38: Parse error: syntax error, unexpected '.', expecting '&' or variable (T_VARIABLE) in /in/0P3BK on line 2
Process exited with code 255.
Output for 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29: Parse error: syntax error, unexpected '.', expecting '&' or T_VARIABLE in /in/0P3BK on line 2
Process exited with code 255.
Output for 5.0.0 - 5.0.5: Parse error: parse error, unexpected '.', expecting '&' or T_VARIABLE in /in/0P3BK on line 2
Process exited with code 255.
Output for 4.4.2 - 4.4.9: Parse error: syntax error, unexpected T_STRING, expecting ')' in /in/0P3BK on line 2
Process exited with code 255.
Output for 4.3.0 - 4.3.1, 4.3.5 - 4.3.11, 4.4.0 - 4.4.1: Parse error: parse error, unexpected T_STRING, expecting ')' in /in/0P3BK on line 2
Process exited with code 255.
Output for 4.3.2 - 4.3.4: Parse error: parse error, expecting `')'' in /in/0P3BK on line 2
Process exited with code 255.