diff --git a/src/Symfony/Component/Serializer/Normalizer/AbstractNormalizer.php b/src/Symfony/Component/Serializer/Normalizer/AbstractNormalizer.php
index 80ea6903dad25..791a744d9dadd 100644
--- a/src/Symfony/Component/Serializer/Normalizer/AbstractNormalizer.php
+++ b/src/Symfony/Component/Serializer/Normalizer/AbstractNormalizer.php
@@ -378,32 +378,32 @@ protected function instantiateObject(array &$data, string $class, array &$contex
                 } elseif ($allowed && !$ignored && (isset($data[$key]) || \array_key_exists($key, $data))) {
                     $parameterData = $data[$key];
                     if (null === $parameterData && $constructorParameter->allowsNull()) {
-                        $params[] = null;
+                        $params[$paramName] = null;
                         $unsetKeys[] = $key;
 
                         continue;
                     }
 
                     try {
-                        $params[] = $this->denormalizeParameter($reflectionClass, $constructorParameter, $paramName, $parameterData, $context, $format);
+                        $params[$paramName] = $this->denormalizeParameter($reflectionClass, $constructorParameter, $paramName, $parameterData, $context, $format);
                     } catch (NotNormalizableValueException $exception) {
                         if (!isset($context['not_normalizable_value_exceptions'])) {
                             throw $exception;
                         }
 
                         $context['not_normalizable_value_exceptions'][] = $exception;
-                        $params[] = $parameterData;
+                        $params[$paramName] = $parameterData;
                     }
 
                     $unsetKeys[] = $key;
                 } elseif (\array_key_exists($key, $context[static::DEFAULT_CONSTRUCTOR_ARGUMENTS][$class] ?? [])) {
-                    $params[] = $context[static::DEFAULT_CONSTRUCTOR_ARGUMENTS][$class][$key];
+                    $params[$paramName] = $context[static::DEFAULT_CONSTRUCTOR_ARGUMENTS][$class][$key];
                 } elseif (\array_key_exists($key, $this->defaultContext[self::DEFAULT_CONSTRUCTOR_ARGUMENTS][$class] ?? [])) {
-                    $params[] = $this->defaultContext[self::DEFAULT_CONSTRUCTOR_ARGUMENTS][$class][$key];
+                    $params[$paramName] = $this->defaultContext[self::DEFAULT_CONSTRUCTOR_ARGUMENTS][$class][$key];
                 } elseif ($constructorParameter->isDefaultValueAvailable()) {
-                    $params[] = $constructorParameter->getDefaultValue();
+                    $params[$paramName] = $constructorParameter->getDefaultValue();
                 } elseif ($constructorParameter->hasType() && $constructorParameter->getType()->allowsNull()) {
-                    $params[] = null;
+                    $params[$paramName] = null;
                 } else {
                     if (!isset($context['not_normalizable_value_exceptions'])) {
                         $missingConstructorArguments[] = $constructorParameter->name;
diff --git a/src/Symfony/Component/Serializer/Tests/Fixtures/Php80WithOptionalConstructorParameter.php b/src/Symfony/Component/Serializer/Tests/Fixtures/Php80WithOptionalConstructorParameter.php
new file mode 100644
index 0000000000000..6593635df4125
--- /dev/null
+++ b/src/Symfony/Component/Serializer/Tests/Fixtures/Php80WithOptionalConstructorParameter.php
@@ -0,0 +1,22 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Serializer\Tests\Fixtures;
+
+final class Php80WithOptionalConstructorParameter
+{
+    public function __construct(
+        public string $one,
+        public string $two,
+        public ?string $three = null,
+    ) {
+    }
+}
diff --git a/src/Symfony/Component/Serializer/Tests/SerializerTest.php b/src/Symfony/Component/Serializer/Tests/SerializerTest.php
index 265c3f2c3d246..447e0f882a8c5 100644
--- a/src/Symfony/Component/Serializer/Tests/SerializerTest.php
+++ b/src/Symfony/Component/Serializer/Tests/SerializerTest.php
@@ -69,6 +69,7 @@
 use Symfony\Component\Serializer\Tests\Fixtures\FalseBuiltInDummy;
 use Symfony\Component\Serializer\Tests\Fixtures\NormalizableTraversableDummy;
 use Symfony\Component\Serializer\Tests\Fixtures\Php74Full;
+use Symfony\Component\Serializer\Tests\Fixtures\Php80WithOptionalConstructorParameter;
 use Symfony\Component\Serializer\Tests\Fixtures\Php80WithPromotedTypedConstructor;
 use Symfony\Component\Serializer\Tests\Fixtures\TraversableDummy;
 use Symfony\Component\Serializer\Tests\Fixtures\WithTypedConstructor;
@@ -1433,6 +1434,61 @@ public static function provideCollectDenormalizationErrors()
             [new ClassMetadataFactory(new AnnotationLoader(new AnnotationReader()))],
         ];
     }
+
+    /**
+     * @requires PHP 8
+     */
+    public function testPartialDenormalizationWithMissingConstructorTypes()
+    {
+        $json = '{"one": "one string", "three": "three string"}';
+
+        $extractor = new PropertyInfoExtractor([], [new ReflectionExtractor()]);
+
+        $serializer = new Serializer(
+            [new ObjectNormalizer(null, null, null, $extractor)],
+            ['json' => new JsonEncoder()]
+        );
+
+        try {
+            $serializer->deserialize($json, Php80WithOptionalConstructorParameter::class, 'json', [
+                DenormalizerInterface::COLLECT_DENORMALIZATION_ERRORS => true,
+            ]);
+
+            $this->fail();
+        } catch (\Throwable $th) {
+            $this->assertInstanceOf(PartialDenormalizationException::class, $th);
+        }
+
+        $this->assertInstanceOf(Php80WithOptionalConstructorParameter::class, $object = $th->getData());
+
+        $this->assertSame('one string', $object->one);
+        $this->assertFalse(isset($object->two));
+        $this->assertSame('three string', $object->three);
+
+        $exceptionsAsArray = array_map(function (NotNormalizableValueException $e): array {
+            return [
+                'currentType' => $e->getCurrentType(),
+                'expectedTypes' => $e->getExpectedTypes(),
+                'path' => $e->getPath(),
+                'useMessageForUser' => $e->canUseMessageForUser(),
+                'message' => $e->getMessage(),
+            ];
+        }, $th->getErrors());
+
+        $expected = [
+            [
+                'currentType' => 'array',
+                'expectedTypes' => [
+                    'unknown',
+                ],
+                'path' => null,
+                'useMessageForUser' => true,
+                'message' => 'Failed to create object because the class misses the "two" property.',
+            ],
+        ];
+
+        $this->assertSame($expected, $exceptionsAsArray);
+    }
 }
 
 class Model