3v4l.org

run code in 300+ PHP versions simultaneously
<?php class Test { public function foo() { $x = ['foo', 'bar']; // The actual operation isn't important, just need to do something to turn the literal // strings into refcounted strings var_dump(__LINE__); debug_zval_dump($x[0]); $y = array_map(function($it) { return $it.$it; }, $x); var_dump(__LINE__); debug_zval_dump($x[0]); debug_zval_dump($y[0]); $z = array_unique($y, SORT_STRING); var_dump(__LINE__); debug_zval_dump($x[0]); debug_zval_dump($y[0]); debug_zval_dump($z[0]); return $z; } } $result = (new Test())->foo(); var_dump(__LINE__); debug_zval_dump($result[0]); debug_zval_dump($result[1]); var_dump($result);
based on UvYaH
Output for 7.1.0 - 7.1.20, 7.2.6 - 7.2.33, 7.3.16 - 7.3.28, 7.4.0 - 7.4.16, 8.0.0 - 8.0.3
int(10) string(3) "foo" refcount(2) int(13) string(3) "foo" refcount(2) string(6) "foofoo" refcount(2) int(17) string(3) "foo" refcount(2) string(6) "foofoo" refcount(3) string(6) "foofoo" refcount(3) int(26) string(6) "foofoo" refcount(2) string(6) "barbar" refcount(2) array(2) { [0]=> string(6) "foofoo" [1]=> string(6) "barbar" }
Output for 7.0.0 - 7.0.24
int(10) string(3) "foo" refcount(3) int(13) string(3) "foo" refcount(3) string(6) "foofoo" refcount(2) int(17) string(3) "foo" refcount(3) string(6) "foofoo" refcount(3) string(6) "foofoo" refcount(3) int(26) string(6) "foofoo" refcount(2) string(6) "barbar" refcount(2) array(2) { [0]=> string(6) "foofoo" [1]=> string(6) "barbar" }