PHP 7.4 fix - Ensure the existence of the 'args' key.

Author: drupol

src/DocBlock/Tags/InvalidTag.php

@@ -104,6 +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);
 
                     return $call;