--TEST-- usort() in combination with "Call to a member function method() on null" --FILE-- compare($a, $b); } catch (Error $e) { var_dump($e->getCode(), $e->getMessage()); return 0; } }); var_dump($list); echo "Alive\n"; ?> --EXPECT-- int(0) string(43) "Call to a member function compare() on null" int(0) string(43) "Call to a member function compare() on null" int(0) string(43) "Call to a member function compare() on null" int(0) string(43) "Call to a member function compare() on null" array(5) { [0]=> int(1) [1]=> int(4) [2]=> int(2) [3]=> int(3) [4]=> int(-1) } Alive