WP_User_Query unexpected output after upgrading toWordPress 4.0.1

You shouldn’t be passing in $users["results"] directly to a foreach without checking that $users is an array, and that it has a ‘results’ key. What if $users is empty, or false, and a WP_Error object?

In this case, it isn’t an array, it’s a WP_User_Query object. Casting it to an array won’t fix that. Instead you should be using it like this:

$user_query = new WP_User_Query( $args );

if ( ! empty( $user_query->results ) ) {
    foreach ( $user_query->results as $user ) {
        echo '<p>' . $user->display_name . '</p>';
    }
} else {
    echo 'No users found.';
}

Where $user_query->results is an array in the $user_query object

Not like this:

// this will fail!
$user_query = new WP_User_Query( $args );
$user_query = ( array ) $user_query;
foreach ( $user_query["results"] as $user ) {
    echo '<p>' . $user->display_name . '</p>';
}

Further reading

• WP Codex WP_User_Query
• Type Juggling PHP.net