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run code in 200+ php & hhvm versions
Bugs & Features
<?php $in = [0]; $out = array_filter($in, function(&$v) { $v = 1; return 1; }); var_dump($in, $out);
Output for 7.0.0 - 7.3.0rc6
array(1) { [0]=> int(0) } array(1) { [0]=> int(0) }
Output for 5.6.0 - 5.6.25
array(1) { [0]=> int(1) } array(1) { [0]=> int(1) }