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<?php $credentials = array(); var_dump( $credentials['user_login'] ); var_dump( array( &$credentials['user_login'] ) ); var_dump( $credentials['user_login'] );
Output for 8.0.1 - 8.0.30, 8.1.0 - 8.1.26, 8.2.0 - 8.2.13, 8.3.0
Warning: Undefined array key "user_login" in /in/8JMRM on line 4 NULL array(1) { [0]=> &NULL } NULL
Output for 7.4.0 - 7.4.33
Notice: Undefined index: user_login in /in/8JMRM on line 4 NULL array(1) { [0]=> &NULL } NULL

preferences:
91.83 ms | 402 KiB | 108 Q