vendor/symfony/serializer/Normalizer/ObjectNormalizer.php line 351

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  2.             if (null !== $discriminatorMapping = $this->classDiscriminatorResolver->getMappingForClass($class)) {
  3.                 $attributes = [];
  4.                 foreach ($discriminatorMapping->getTypesMapping() as $mappedClass) {
  5.                     $attributes[] = parent::getAllowedAttributes($mappedClass, $context, $attributesAsString);
  6.                 }
  7.                 $allowedAttributes = array_merge($allowedAttributes, ...$attributes);
  8.             }
  9.         }
  11.         return $allowedAttributes;
  12.     }
  13. }