Ignore missing SMTP class in PHPMailer

.phpstan.neon

@@ -40,3 +40,27 @@ parameters:
             # Ignore missing IMAP\Connection class in PHP <= 8.0
             message: '(^Parameter .+ has invalid type IMAP\\Connection\.$)'
             path: src
+
+        -
+            # Ignore missing SMTP class in PHPMailer 5.2.21
+            # see https://github.com/PHPMailer/PHPMailer/blob/v5.2.21/class.smtp.php
+            message: '(^.+ an unknown class SMTP\.$)'
+            path: addon/mailstream/phpmailer
+
+        -
+            # Ignore missing SMTP class in PHPMailer 5.2.21
+            # see https://github.com/PHPMailer/PHPMailer/blob/v5.2.21/class.smtp.php
+            message: '(^Property .+ has unknown class SMTP as its type\.$)'
+            path: addon/mailstream/phpmailer
+
+        -
+            # Ignore missing SMTP class in PHPMailer 5.2.21
+            # see https://github.com/PHPMailer/PHPMailer/blob/v5.2.21/class.smtp.php
+            message: '(^Method .+ has invalid return type SMTP\.$)'
+            path: addon/mailstream/phpmailer
+
+        -
+            # Ignore missing SMTP class in PHPMailer 5.2.21
+            # see https://github.com/PHPMailer/PHPMailer/blob/v5.2.21/class.smtp.php
+            message: '(^Instantiated class SMTP not found\.$)'
+            path: addon/mailstream/phpmailer