Use a type-secure check

diff --git a/wcfsetup/install/files/lib/system/mail/MailSender.class.php b/wcfsetup/install/files/lib/system/mail/MailSender.class.php
index 674a122212768b841e3030deff32e6ab0e1bfdc1..4c7f7208e0a1f84dd8797044c3cfe4f8e2cb83e4 100644 (file)
--- a/wcfsetup/install/files/lib/system/mail/MailSender.class.php
+++ b/wcfsetup/install/files/lib/system/mail/MailSender.class.php
@@ -24,7 +24,7 @@ abstract class MailSender {
         * @return      MailSender
         */
        public static function getInstance() {
-               if (self::$instance == null) {
+               if (self::$instance === null) {
                        switch (MAIL_SEND_METHOD) {
                                case 'php':
                                        self::$instance = new PHPMailSender();