Use FQN since class is not imported

src/Monolog/Handler/StreamHandler.php

@@ -35,7 +35,7 @@ class StreamHandler extends AbstractProcessingHandler
      * @param int|null        $filePermission Optional file permissions (default (0644) are only for owner read/write)
      * @param Boolean         $useLocking     Try to lock log file before doing any writes
      *
-     * @throws InvalidArgumentException If stream is not a resource or string
+     * @throws \InvalidArgumentException If stream is not a resource or string
      */
     public function __construct($stream, $level = Logger::DEBUG, $bubble = true, $filePermission = null, $useLocking = false)
     {