PHP 7.4 fix - Check if 'args' key exists, if not, use an empty array.

Author: drupol

src/DocBlock/Tags/InvalidTag.php

@@ -104,8 +104,7 @@ static function (&$value) : void {
         do {
             $trace = array_map(
                 static function (array $call) use ($flatten) : array {
-                    $call += ['args' => []];
-                    array_walk_recursive($call['args'], $flatten);
+                    array_walk_recursive($call['args'] ?? [], $flatten);
 
                     return $call;
                 },