3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $foo = new ArrayObject(); $bar = new ArrayObject(); $bar[] = null; $foo[] = $bar; var_dump(json_encode($foo));
based on f4J2T
Output for 5.2.0 - 5.6.28, hhvm-3.10.0 - 3.13.2, 7.0.0 - 7.1.0
string(16) "{"0":{"0":null}}"
Output for 5.0.0 - 5.1.6
Fatal error: Call to undefined function json_encode() in /in/OZJpe on line 7
Process exited with code 255.
Output for 4.3.2 - 4.4.9
Fatal error: Cannot instantiate non-existent class: arrayobject in /in/OZJpe on line 3
Process exited with code 255.
Output for 4.3.0 - 4.3.1
Fatal error: Cannot instantiate non-existent class: arrayobject in /in/OZJpe on line 3