diff --git a/src/Symfony/Component/DependencyInjection/Tests/Compiler/AutowirePassTest.php b/src/Symfony/Component/DependencyInjection/Tests/Compiler/AutowirePassTest.php
index e11154889c..2482db6314 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Compiler/AutowirePassTest.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Compiler/AutowirePassTest.php
@@ -254,6 +254,25 @@ class AutowirePassTest extends TestCase
         $pass->process($container);
     }
 
+    /**
+     * @requires PHP 8
+     */
+    public function testTypeNotGuessableUnionType()
+    {
+        $this->expectException('Symfony\Component\DependencyInjection\Exception\AutowiringFailedException');
+        $this->expectExceptionMessage('Cannot autowire service "a": argument "$collision" of method "Symfony\Component\DependencyInjection\Tests\Compiler\UnionClasses::__construct()" has type "Symfony\Component\DependencyInjection\Tests\Compiler\CollisionA|Symfony\Component\DependencyInjection\Tests\Compiler\CollisionB" but this class was not found.');
+        $container = new ContainerBuilder();
+
+        $container->register(CollisionA::class);
+        $container->register(CollisionB::class);
+
+        $aDefinition = $container->register('a', UnionClasses::class);
+        $aDefinition->setAutowired(true);
+
+        $pass = new AutowirePass();
+        $pass->process($container);
+    }
+
     public function testTypeNotGuessableWithTypeSet()
     {
         $container = new ContainerBuilder();
@@ -350,6 +369,40 @@ class AutowirePassTest extends TestCase
         $this->assertEquals(Foo::class, $definition->getArgument(2));
     }
 
+    /**
+     * @requires PHP 8
+     */
+    public function testParameterWithNullUnionIsSkipped()
+    {
+        $container = new ContainerBuilder();
+
+        $optDefinition = $container->register('opt', UnionNull::class);
+        $optDefinition->setAutowired(true);
+
+        (new AutowirePass())->process($container);
+
+        $definition = $container->getDefinition('opt');
+        $this->assertNull($definition->getArgument(0));
+    }
+
+    /**
+     * @requires PHP 8
+     */
+    public function testParameterWithNullUnionIsAutowired()
+    {
+        $container = new ContainerBuilder();
+
+        $container->register(CollisionInterface::class, CollisionA::class);
+
+        $optDefinition = $container->register('opt', UnionNull::class);
+        $optDefinition->setAutowired(true);
+
+        (new AutowirePass())->process($container);
+
+        $definition = $container->getDefinition('opt');
+        $this->assertEquals(CollisionInterface::class, $definition->getArgument(0));
+    }
+
     public function testDontTriggerAutowiring()
     {
         $container = new ContainerBuilder();
@@ -459,6 +512,21 @@ class AutowirePassTest extends TestCase
         (new AutowirePass())->process($container);
     }
 
+    /**
+     * @requires PHP 8
+     */
+    public function testUnionScalarArgsCannotBeAutowired()
+    {
+        $this->expectException('Symfony\Component\DependencyInjection\Exception\AutowiringFailedException');
+        $this->expectExceptionMessage('Cannot autowire service "union_scalars": argument "$timeout" of method "Symfony\Component\DependencyInjection\Tests\Compiler\UnionScalars::__construct()" is type-hinted "int|float", you should configure its value explicitly.');
+        $container = new ContainerBuilder();
+
+        $container->register('union_scalars', UnionScalars::class)
+            ->setAutowired(true);
+
+        (new AutowirePass())->process($container);
+    }
+
     public function testNoTypeArgsCannotBeAutowired()
     {
         $this->expectException('Symfony\Component\DependencyInjection\Exception\AutowiringFailedException');
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Fixtures/includes/autowiring_classes.php b/src/Symfony/Component/DependencyInjection/Tests/Fixtures/includes/autowiring_classes.php
index 8db7edf1a1..42545c9c2b 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Fixtures/includes/autowiring_classes.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Fixtures/includes/autowiring_classes.php
@@ -2,6 +2,10 @@
 
 namespace Symfony\Component\DependencyInjection\Tests\Compiler;
 
+if (PHP_VERSION_ID >= 80000) {
+    require __DIR__.'/uniontype_classes.php';
+}
+
 class Foo
 {
 }
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Fixtures/includes/uniontype_classes.php b/src/Symfony/Component/DependencyInjection/Tests/Fixtures/includes/uniontype_classes.php
new file mode 100644
index 0000000000..3a0c77c539
--- /dev/null
+++ b/src/Symfony/Component/DependencyInjection/Tests/Fixtures/includes/uniontype_classes.php
@@ -0,0 +1,24 @@
+<?php
+
+namespace Symfony\Component\DependencyInjection\Tests\Compiler;
+
+class UnionScalars
+{
+    public function __construct(int|float $timeout)
+    {
+    }
+}
+
+class UnionClasses
+{
+    public function __construct(CollisionA|CollisionB $collision)
+    {
+    }
+}
+
+class UnionNull
+{
+    public function __construct(CollisionInterface|null $c)
+    {
+    }
+}
diff --git a/src/Symfony/Component/PropertyInfo/Extractor/ReflectionExtractor.php b/src/Symfony/Component/PropertyInfo/Extractor/ReflectionExtractor.php
index cbcb349d2e..59af87584b 100644
--- a/src/Symfony/Component/PropertyInfo/Extractor/ReflectionExtractor.php
+++ b/src/Symfony/Component/PropertyInfo/Extractor/ReflectionExtractor.php
@@ -243,12 +243,15 @@ class ReflectionExtractor implements PropertyListExtractorInterface, PropertyTyp
 
         foreach ($reflectionType instanceof \ReflectionUnionType ? $reflectionType->getTypes() : [$reflectionType] as $type) {
             $phpTypeOrClass = $reflectionType instanceof \ReflectionNamedType ? $reflectionType->getName() : (string) $type;
+            if ('null' === $phpTypeOrClass) {
+                continue;
+            }
 
             if (Type::BUILTIN_TYPE_ARRAY === $phpTypeOrClass) {
                 $types[] = new Type(Type::BUILTIN_TYPE_ARRAY, $nullable, null, true);
-            } elseif ('void' === $phpTypeOrClass || 'null' === $phpTypeOrClass) {
+            } elseif ('void' === $phpTypeOrClass) {
                 $types[] = new Type(Type::BUILTIN_TYPE_NULL, $nullable);
-            } elseif ($reflectionType->isBuiltin()) {
+            } elseif ($type->isBuiltin()) {
                 $types[] = new Type($phpTypeOrClass, $nullable);
             } else {
                 $types[] = new Type(Type::BUILTIN_TYPE_OBJECT, $nullable, $this->resolveTypeName($phpTypeOrClass, $reflectionMethod));
diff --git a/src/Symfony/Component/PropertyInfo/Tests/Extractor/ReflectionExtractorTest.php b/src/Symfony/Component/PropertyInfo/Tests/Extractor/ReflectionExtractorTest.php
index 36fc9d55e3..bac036aa5b 100644
--- a/src/Symfony/Component/PropertyInfo/Tests/Extractor/ReflectionExtractorTest.php
+++ b/src/Symfony/Component/PropertyInfo/Tests/Extractor/ReflectionExtractorTest.php
@@ -204,6 +204,26 @@ class ReflectionExtractorTest extends TestCase
         ];
     }
 
+    /**
+     * @dataProvider php80TypesProvider
+     * @requires PHP 8
+     */
+    public function testExtractPhp80Type($property, array $type = null)
+    {
+        $this->assertEquals($type, $this->extractor->getTypes('Symfony\Component\PropertyInfo\Tests\Fixtures\Php80Dummy', $property, []));
+    }
+
+    public function php80TypesProvider()
+    {
+        return [
+            ['foo', [new Type(Type::BUILTIN_TYPE_ARRAY, true, null, true)]],
+            ['bar', [new Type(Type::BUILTIN_TYPE_INT, true)]],
+            ['timeout', [new Type(Type::BUILTIN_TYPE_INT), new Type(Type::BUILTIN_TYPE_FLOAT)]],
+            ['optional', [new Type(Type::BUILTIN_TYPE_INT, true), new Type(Type::BUILTIN_TYPE_FLOAT, true)]],
+            ['string', [new Type(Type::BUILTIN_TYPE_OBJECT, false, 'Stringable'), new Type(Type::BUILTIN_TYPE_STRING)]],
+        ];
+    }
+
     /**
      * @dataProvider getReadableProperties
      */
diff --git a/src/Symfony/Component/PropertyInfo/Tests/Fixtures/Php80Dummy.php b/src/Symfony/Component/PropertyInfo/Tests/Fixtures/Php80Dummy.php
new file mode 100644
index 0000000000..484498f4a6
--- /dev/null
+++ b/src/Symfony/Component/PropertyInfo/Tests/Fixtures/Php80Dummy.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace Symfony\Component\PropertyInfo\Tests\Fixtures;
+
+class Php80Dummy
+{
+    public function getFoo(): array|null
+    {
+    }
+
+    public function setBar(int|null $bar)
+    {
+    }
+
+    public function setTimeout(int|float $timeout)
+    {
+    }
+
+    public function getOptional(): int|float|null
+    {
+    }
+
+    public function setString(string|\Stringable $string)
+    {
+    }
+}