shouldn't PHP array recursion throw an error?

[Kaili]

This is the test and the response I get. I think this could be problematic and should throw an error or a notice but I cannot understand why is tolerated.\[code\]<?php $test = array( 0 => 'test', 1=> &$test ); var_dump( $test ); // array(2) { [0]=> string(4) "test" [1]=> &array(2) { [0]=> string(4) "test" [1]=> &array(2) { [0]=> string(4) "test" [1]=> *RECURSION* } } }?>\[/code\]