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<?php $a = '1234'; $b = '34564'; $z[1] = &$a; $x[] = &$z[1]; $z[1] = &$b; var_dump($a, $b, $z, $x);
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.8 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
string(4) "1234" string(5) "34564" array(1) { [1]=> &string(5) "34564" } array(1) { [0]=> &string(4) "1234" }

preferences:
223.21 ms | 406 KiB | 358 Q