Index: wp-includes/functions.php
===================================================================
--- wp-includes/functions.php	(revision 17521)
+++ wp-includes/functions.php	(working copy)
@@ -3092,12 +3092,13 @@
  * @return array
  */
 function wp_list_pluck( $list, $field ) {
+	$field_values = array();
 	foreach ( $list as $key => $value ) {
 		$value = (array) $value;
-		$list[ $key ] = $value[ $field ];
+		$field_values[ $key ] = $value[ $field ];
 	}
 
-	return $list;
+	return $field_values;
 }
 
 /**