diff --git a/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php b/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
index 25cb14b193..b6a0f513f0 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
@@ -741,7 +741,7 @@ class YamlFileLoader extends FileLoader
                         throw new InvalidArgumentException(sprintf('"!%s" tag contains unsupported key "%s"; supported ones are "tag", "index_by" and "default_index_method".', $value->getTag(), implode('"", "', $diff)));
                     }
 
-                    $argument = new TaggedIteratorArgument($argument['tag'], $argument['index_by'], $argument['default_index_method'] ?? null, $forLocator);
+                    $argument = new TaggedIteratorArgument($argument['tag'], $argument['index_by'] ?? null, $argument['default_index_method'] ?? null, $forLocator);
 
                     if ($forLocator) {
                         $argument = new ServiceLocatorArgument($argument);
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Fixtures/yaml/tagged_iterator_optional.yml b/src/Symfony/Component/DependencyInjection/Tests/Fixtures/yaml/tagged_iterator_optional.yml
new file mode 100644
index 0000000000..4694f543fd
--- /dev/null
+++ b/src/Symfony/Component/DependencyInjection/Tests/Fixtures/yaml/tagged_iterator_optional.yml
@@ -0,0 +1,4 @@
+services:
+    iterator_service:
+        class: FooClass
+        arguments: [!tagged_iterator {tag: test.tag}]
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Loader/YamlFileLoaderTest.php b/src/Symfony/Component/DependencyInjection/Tests/Loader/YamlFileLoaderTest.php
index adb2b925f3..5d7e6bf707 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Loader/YamlFileLoaderTest.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Loader/YamlFileLoaderTest.php
@@ -858,4 +858,18 @@ class YamlFileLoaderTest extends TestCase
 
         $this->assertSame('overridden', $container->get('bar')->quz);
     }
+
+    /**
+     * When creating a tagged iterator using the array syntax, all optional parameters should be properly handled.
+     */
+    public function testDefaultValueOfTagged()
+    {
+        $container = new ContainerBuilder();
+        $loader = new YamlFileLoader($container, new FileLocator(self::$fixturesPath.'/yaml'));
+        $loader->load('tagged_iterator_optional.yml');
+
+        $iteratorArgument = $container->getDefinition('iterator_service')->getArgument(0);
+        $this->assertInstanceOf(TaggedIteratorArgument::class, $iteratorArgument);
+        $this->assertNull($iteratorArgument->getIndexAttribute());
+    }
 }
diff --git a/src/Symfony/Component/Mailer/Bridge/Mailchimp/Http/Api/MandrillTransport.php b/src/Symfony/Component/Mailer/Bridge/Mailchimp/Http/Api/MandrillTransport.php
index bf1c154b5d..67600d42d2 100644
--- a/src/Symfony/Component/Mailer/Bridge/Mailchimp/Http/Api/MandrillTransport.php
+++ b/src/Symfony/Component/Mailer/Bridge/Mailchimp/Http/Api/MandrillTransport.php
@@ -84,7 +84,7 @@ class MandrillTransport extends AbstractApiTransport
         }
 
         $headersToBypass = ['from', 'to', 'cc', 'bcc', 'subject', 'content-type'];
-        foreach ($email->getHeaders()->getAll() as $name => $header) {
+        foreach ($email->getHeaders()->all() as $name => $header) {
             if (\in_array($name, $headersToBypass, true)) {
                 continue;
             }
diff --git a/src/Symfony/Component/Mailer/Bridge/Mailgun/Http/Api/MailgunTransport.php b/src/Symfony/Component/Mailer/Bridge/Mailgun/Http/Api/MailgunTransport.php
index 56f90eb97c..74a3ab2086 100644
--- a/src/Symfony/Component/Mailer/Bridge/Mailgun/Http/Api/MailgunTransport.php
+++ b/src/Symfony/Component/Mailer/Bridge/Mailgun/Http/Api/MailgunTransport.php
@@ -45,7 +45,7 @@ class MailgunTransport extends AbstractApiTransport
     {
         $body = new FormDataPart($this->getPayload($email, $envelope));
         $headers = [];
-        foreach ($body->getPreparedHeaders()->getAll() as $header) {
+        foreach ($body->getPreparedHeaders()->all() as $header) {
             $headers[] = $header->toString();
         }
 
@@ -98,7 +98,7 @@ class MailgunTransport extends AbstractApiTransport
         }
 
         $headersToBypass = ['from', 'to', 'cc', 'bcc', 'subject', 'content-type'];
-        foreach ($headers->getAll() as $name => $header) {
+        foreach ($headers->all() as $name => $header) {
             if (\in_array($name, $headersToBypass, true)) {
                 continue;
             }
diff --git a/src/Symfony/Component/Mailer/Bridge/Mailgun/Http/MailgunTransport.php b/src/Symfony/Component/Mailer/Bridge/Mailgun/Http/MailgunTransport.php
index 6ddf1f3ed5..1ba6df4745 100644
--- a/src/Symfony/Component/Mailer/Bridge/Mailgun/Http/MailgunTransport.php
+++ b/src/Symfony/Component/Mailer/Bridge/Mailgun/Http/MailgunTransport.php
@@ -47,7 +47,7 @@ class MailgunTransport extends AbstractHttpTransport
             'message' => new DataPart($message->toString(), 'message.mime'),
         ]);
         $headers = [];
-        foreach ($body->getPreparedHeaders()->getAll() as $header) {
+        foreach ($body->getPreparedHeaders()->all() as $header) {
             $headers[] = $header->toString();
         }
         $endpoint = str_replace(['%domain%', '%region_dot%'], [urlencode($this->domain), 'us' !== ($this->region ?: 'us') ? $this->region.'.' : ''], self::ENDPOINT);
diff --git a/src/Symfony/Component/Mailer/Bridge/Postmark/Http/Api/PostmarkTransport.php b/src/Symfony/Component/Mailer/Bridge/Postmark/Http/Api/PostmarkTransport.php
index 8114395762..5d327182b5 100644
--- a/src/Symfony/Component/Mailer/Bridge/Postmark/Http/Api/PostmarkTransport.php
+++ b/src/Symfony/Component/Mailer/Bridge/Postmark/Http/Api/PostmarkTransport.php
@@ -69,7 +69,7 @@ class PostmarkTransport extends AbstractApiTransport
         ];
 
         $headersToBypass = ['from', 'to', 'cc', 'bcc', 'subject', 'content-type', 'sender'];
-        foreach ($email->getHeaders()->getAll() as $name => $header) {
+        foreach ($email->getHeaders()->all() as $name => $header) {
             if (\in_array($name, $headersToBypass, true)) {
                 continue;
             }
diff --git a/src/Symfony/Component/Mailer/Bridge/Sendgrid/Http/Api/SendgridTransport.php b/src/Symfony/Component/Mailer/Bridge/Sendgrid/Http/Api/SendgridTransport.php
index 3beec418da..628951aaf9 100644
--- a/src/Symfony/Component/Mailer/Bridge/Sendgrid/Http/Api/SendgridTransport.php
+++ b/src/Symfony/Component/Mailer/Bridge/Sendgrid/Http/Api/SendgridTransport.php
@@ -83,7 +83,7 @@ class SendgridTransport extends AbstractApiTransport
         // these headers can't be overwritten according to Sendgrid docs
         // see https://developers.pepipost.com/migration-api/new-subpage/email-send
         $headersToBypass = ['x-sg-id', 'x-sg-eid', 'received', 'dkim-signature', 'content-transfer-encoding', 'from', 'to', 'cc', 'bcc', 'subject', 'content-type', 'reply-to'];
-        foreach ($email->getHeaders()->getAll() as $name => $header) {
+        foreach ($email->getHeaders()->all() as $name => $header) {
             if (\in_array($name, $headersToBypass, true)) {
                 continue;
             }
diff --git a/src/Symfony/Component/Mailer/DelayedSmtpEnvelope.php b/src/Symfony/Component/Mailer/DelayedSmtpEnvelope.php
index 4c5ed46cfe..f32b240476 100644
--- a/src/Symfony/Component/Mailer/DelayedSmtpEnvelope.php
+++ b/src/Symfony/Component/Mailer/DelayedSmtpEnvelope.php
@@ -71,7 +71,7 @@ final class DelayedSmtpEnvelope extends SmtpEnvelope
     {
         $recipients = [];
         foreach (['to', 'cc', 'bcc'] as $name) {
-            foreach ($headers->getAll($name) as $header) {
+            foreach ($headers->all($name) as $header) {
                 foreach ($header->getAddresses() as $address) {
                     $recipients[] = new Address($address->getAddress());
                 }
diff --git a/src/Symfony/Component/Mailer/EventListener/MessageListener.php b/src/Symfony/Component/Mailer/EventListener/MessageListener.php
index 6211ffb25b..f300f6370a 100644
--- a/src/Symfony/Component/Mailer/EventListener/MessageListener.php
+++ b/src/Symfony/Component/Mailer/EventListener/MessageListener.php
@@ -51,7 +51,7 @@ class MessageListener implements EventSubscriberInterface
         }
 
         $headers = $message->getHeaders();
-        foreach ($this->headers->getAll() as $name => $header) {
+        foreach ($this->headers->all() as $name => $header) {
             if (!$headers->has($name)) {
                 $headers->add($header);
             } else {
diff --git a/src/Symfony/Component/Mime/Email.php b/src/Symfony/Component/Mime/Email.php
index 557f2dbb52..9d9b48eff5 100644
--- a/src/Symfony/Component/Mime/Email.php
+++ b/src/Symfony/Component/Mime/Email.php
@@ -101,7 +101,7 @@ class Email extends Message
     }
 
     /**
-     * @param Address|NamedAddress|string $addresses
+     * @param Address|NamedAddress|string ...$addresses
      *
      * @return $this
      */
@@ -111,7 +111,7 @@ class Email extends Message
     }
 
     /**
-     * @param Address|NamedAddress|string $addresses
+     * @param Address|NamedAddress|string ...$addresses
      *
      * @return $this
      */
@@ -129,7 +129,7 @@ class Email extends Message
     }
 
     /**
-     * @param Address|string $addresses
+     * @param Address|string ...$addresses
      *
      * @return $this
      */
@@ -139,7 +139,7 @@ class Email extends Message
     }
 
     /**
-     * @param Address|string $addresses
+     * @param Address|string ...$addresses
      *
      * @return $this
      */
@@ -157,7 +157,7 @@ class Email extends Message
     }
 
     /**
-     * @param Address|NamedAddress|string $addresses
+     * @param Address|NamedAddress|string ...$addresses
      *
      * @return $this
      */
@@ -167,7 +167,7 @@ class Email extends Message
     }
 
     /**
-     * @param Address|NamedAddress|string $addresses
+     * @param Address|NamedAddress|string ...$addresses
      *
      * @return $this
      */
@@ -185,7 +185,7 @@ class Email extends Message
     }
 
     /**
-     * @param Address|NamedAddress|string $addresses
+     * @param Address|NamedAddress|string ...$addresses
      *
      * @return $this
      */
@@ -195,7 +195,7 @@ class Email extends Message
     }
 
     /**
-     * @param Address|string $addresses
+     * @param Address|string ...$addresses
      *
      * @return $this
      */
@@ -213,7 +213,7 @@ class Email extends Message
     }
 
     /**
-     * @param Address|NamedAddress|string $addresses
+     * @param Address|NamedAddress|string ...$addresses
      *
      * @return $this
      */
@@ -223,7 +223,7 @@ class Email extends Message
     }
 
     /**
-     * @param Address|string $addresses
+     * @param Address|string ...$addresses
      *
      * @return $this
      */
diff --git a/src/Symfony/Component/Mime/Header/Headers.php b/src/Symfony/Component/Mime/Header/Headers.php
index 2797058266..dc8cb3476b 100644
--- a/src/Symfony/Component/Mime/Header/Headers.php
+++ b/src/Symfony/Component/Mime/Header/Headers.php
@@ -49,7 +49,7 @@ final class Headers
     public function setMaxLineLength(int $lineLength)
     {
         $this->lineLength = $lineLength;
-        foreach ($this->getAll() as $header) {
+        foreach ($this->all() as $header) {
             $header->setMaxLineLength($lineLength);
         }
     }
@@ -175,7 +175,7 @@ final class Headers
         return array_shift($values);
     }
 
-    public function getAll(string $name = null): iterable
+    public function all(string $name = null): iterable
     {
         if (null === $name) {
             foreach ($this->headers as $name => $collection) {
@@ -218,7 +218,7 @@ final class Headers
     public function toArray(): array
     {
         $arr = [];
-        foreach ($this->getAll() as $header) {
+        foreach ($this->all() as $header) {
             if ('' !== $header->getBodyAsString()) {
                 $arr[] = $header->toString();
             }
diff --git a/src/Symfony/Component/Mime/Tests/Header/HeadersTest.php b/src/Symfony/Component/Mime/Tests/Header/HeadersTest.php
index 2f4a1dd635..3568c9a6e4 100644
--- a/src/Symfony/Component/Mime/Tests/Header/HeadersTest.php
+++ b/src/Symfony/Component/Mime/Tests/Header/HeadersTest.php
@@ -141,7 +141,7 @@ class HeadersTest extends TestCase
         $this->assertNull($headers->get('Message-ID'));
     }
 
-    public function testGetAllReturnsAllHeadersMatchingName()
+    public function testAllReturnsAllHeadersMatchingName()
     {
         $header0 = new UnstructuredHeader('X-Test', 'some@id');
         $header1 = new UnstructuredHeader('X-Test', 'other@id');
@@ -150,10 +150,10 @@ class HeadersTest extends TestCase
         $headers->addTextHeader('X-Test', 'some@id');
         $headers->addTextHeader('X-Test', 'other@id');
         $headers->addTextHeader('X-Test', 'more@id');
-        $this->assertEquals([$header0, $header1, $header2], iterator_to_array($headers->getAll('X-Test')));
+        $this->assertEquals([$header0, $header1, $header2], iterator_to_array($headers->all('X-Test')));
     }
 
-    public function testGetAllReturnsAllHeadersIfNoArguments()
+    public function testAllReturnsAllHeadersIfNoArguments()
     {
         $header0 = new IdentificationHeader('Message-ID', 'some@id');
         $header1 = new UnstructuredHeader('Subject', 'thing');
@@ -162,13 +162,13 @@ class HeadersTest extends TestCase
         $headers->addIdHeader('Message-ID', 'some@id');
         $headers->addTextHeader('Subject', 'thing');
         $headers->addMailboxListHeader('To', [new Address('person@example.org')]);
-        $this->assertEquals(['message-id' => $header0, 'subject' => $header1, 'to' => $header2], iterator_to_array($headers->getAll()));
+        $this->assertEquals(['message-id' => $header0, 'subject' => $header1, 'to' => $header2], iterator_to_array($headers->all()));
     }
 
-    public function testGetAllReturnsEmptyArrayIfNoneSet()
+    public function testAllReturnsEmptyArrayIfNoneSet()
     {
         $headers = new Headers();
-        $this->assertEquals([], iterator_to_array($headers->getAll('Received')));
+        $this->assertEquals([], iterator_to_array($headers->all('Received')));
     }
 
     public function testRemoveRemovesAllHeadersWithName()
@@ -199,12 +199,12 @@ class HeadersTest extends TestCase
         $this->assertEquals($header, $headers->get('message-id'));
     }
 
-    public function testGetAllIsNotCaseSensitive()
+    public function testAllIsNotCaseSensitive()
     {
         $header = new IdentificationHeader('Message-ID', 'some@id');
         $headers = new Headers();
         $headers->addIdHeader('Message-ID', 'some@id');
-        $this->assertEquals([$header], iterator_to_array($headers->getAll('message-id')));
+        $this->assertEquals([$header], iterator_to_array($headers->all('message-id')));
     }
 
     public function testRemoveIsNotCaseSensitive()
diff --git a/src/Symfony/Component/Mime/Tests/MessageTest.php b/src/Symfony/Component/Mime/Tests/MessageTest.php
index dbeb0a5544..cc806b919e 100644
--- a/src/Symfony/Component/Mime/Tests/MessageTest.php
+++ b/src/Symfony/Component/Mime/Tests/MessageTest.php
@@ -68,7 +68,7 @@ class MessageTest extends TestCase
         $message = new Message();
         $message->getHeaders()->addMailboxListHeader('From', ['fabien@symfony.com']);
         $h = $message->getPreparedHeaders();
-        $this->assertCount(4, iterator_to_array($h->getAll()));
+        $this->assertCount(4, iterator_to_array($h->all()));
         $this->assertEquals(new MailboxListHeader('From', [new Address('fabien@symfony.com')]), $h->get('From'));
         $this->assertEquals(new UnstructuredHeader('MIME-Version', '1.0'), $h->get('mime-version'));
         $this->assertTrue($h->has('Message-Id'));