From 90c83b214c39c26633c3f7a0d4b8541bef6c6a26 Mon Sep 17 00:00:00 2001
From: Wouter de Jong <wouter@wouterj.nl>
Date: Sun, 8 Nov 2020 14:35:47 +0100
Subject: [PATCH 1/3] Added PHP types to the Doctrine related articles

---
 doctrine.rst                          | 193 ++++++++++++++++----------
 doctrine/associations.rst             |  81 +++++++----
 doctrine/dbal.rst                     |   4 +-
 doctrine/events.rst                   |  16 +--
 doctrine/multiple_entity_managers.rst |   9 +-
 doctrine/resolve_target_entity.rst    |   5 +-
 6 files changed, 186 insertions(+), 122 deletions(-)

diff --git a/doctrine.rst b/doctrine.rst
index 21b14c2ae4c..8226bf22700 100644
--- a/doctrine.rst
+++ b/doctrine.rst
@@ -51,7 +51,7 @@ The database connection information is stored as an environment variable called
 
     # to use sqlite:
     # DATABASE_URL="sqlite:///%kernel.project_dir%/var/app.db"
-    
+
     # to use postgresql:
     # DATABASE_URL="postgresql://db_user:db_password@127.0.0.1:5432/db_name?serverVersion=11&charset=utf8"
 
@@ -506,46 +506,60 @@ Fetching an object back out of the database is even easier. Suppose you want to
 be able to go to ``/product/1`` to see your new product::
 
     // src/Controller/ProductController.php
+    namespace App\Controller;
+
+    use App\Entity\Product;
+    use Symfony\Component\HttpFoundation\Response;
     // ...
 
-    /**
-     * @Route("/product/{id}", name="product_show")
-     */
-    public function show($id)
+    class ProductController extends AbstractController
     {
-        $product = $this->getDoctrine()
-            ->getRepository(Product::class)
-            ->find($id);
-
-        if (!$product) {
-            throw $this->createNotFoundException(
-                'No product found for id '.$id
-            );
-        }
+        /**
+         * @Route("/product/{id}", name="product_show")
+         */
+        public function show(int $id): Response
+        {
+            $product = $this->getDoctrine()
+                ->getRepository(Product::class)
+                ->find($id);
+
+            if (!$product) {
+                throw $this->createNotFoundException(
+                    'No product found for id '.$id
+                );
+            }
 
-        return new Response('Check out this great product: '.$product->getName());
+            return new Response('Check out this great product: '.$product->getName());
 
-        // or render a template
-        // in the template, print things with {{ product.name }}
-        // return $this->render('product/show.html.twig', ['product' => $product]);
+            // or render a template
+            // in the template, print things with {{ product.name }}
+            // return $this->render('product/show.html.twig', ['product' => $product]);
+        }
     }
 
 Another possibility is to use the ``ProductRepository`` using Symfony's autowiring
 and injected by the dependency injection container::
 
     // src/Controller/ProductController.php
-    // ...
+    namespace App\Controller;
+
+    use App\Entity\Product;
     use App\Repository\ProductRepository;
+    use Symfony\Component\HttpFoundation\Response;
+    // ...
 
-    /**
-     * @Route("/product/{id}", name="product_show")
-     */
-    public function show($id, ProductRepository $productRepository)
+    class ProductController extends AbstractController
     {
-        $product = $productRepository
-            ->find($id);
+        /**
+         * @Route("/product/{id}", name="product_show")
+         */
+        public function show(int $id, ProductRepository $productRepository): Response
+        {
+            $product = $productRepository
+                ->find($id);
 
-        // ...
+            // ...
+        }
     }
 
 Try it out!
@@ -611,15 +625,23 @@ for you automatically! First, install the bundle in case you don't have it:
 Now, simplify your controller::
 
     // src/Controller/ProductController.php
+    namespace App\Controller;
+
     use App\Entity\Product;
+    use App\Repository\ProductRepository;
+    use Symfony\Component\HttpFoundation\Response;
+    // ...
 
-    /**
-     * @Route("/product/{id}", name="product_show")
-     */
-    public function show(Product $product)
+    class ProductController extends AbstractController
     {
-        // use the Product!
-        // ...
+        /**
+         * @Route("/product/{id}", name="product_show")
+         */
+        public function show(Product $product): Response
+        {
+            // use the Product!
+            // ...
+        }
     }
 
 That's it! The bundle uses the ``{id}`` from the route to query for the ``Product``
@@ -633,26 +655,37 @@ Updating an Object
 Once you've fetched an object from Doctrine, you interact with it the same as
 with any PHP model::
 
-    /**
-     * @Route("/product/edit/{id}")
-     */
-    public function update($id)
+    // src/Controller/ProductController.php
+    namespace App\Controller;
+
+    use App\Entity\Product;
+    use App\Repository\ProductRepository;
+    use Symfony\Component\HttpFoundation\Response;
+    // ...
+
+    class ProductController extends AbstractController
     {
-        $entityManager = $this->getDoctrine()->getManager();
-        $product = $entityManager->getRepository(Product::class)->find($id);
+        /**
+         * @Route("/product/edit/{id}")
+         */
+        public function update(int $id): Response
+        {
+            $entityManager = $this->getDoctrine()->getManager();
+            $product = $entityManager->getRepository(Product::class)->find($id);
 
-        if (!$product) {
-            throw $this->createNotFoundException(
-                'No product found for id '.$id
-            );
-        }
+            if (!$product) {
+                throw $this->createNotFoundException(
+                    'No product found for id '.$id
+                );
+            }
 
-        $product->setName('New product name!');
-        $entityManager->flush();
+            $product->setName('New product name!');
+            $entityManager->flush();
 
-        return $this->redirectToRoute('product_show', [
-            'id' => $product->getId()
-        ]);
+            return $this->redirectToRoute('product_show', [
+                'id' => $product->getId()
+            ]);
+        }
     }
 
 Using Doctrine to edit an existing product consists of three steps:
@@ -728,7 +761,7 @@ a new method for this to your repository::
         /**
          * @return Product[]
          */
-        public function findAllGreaterThanPrice($price): array
+        public function findAllGreaterThanPrice(int $price): array
         {
             $entityManager = $this->getEntityManager();
 
@@ -773,25 +806,28 @@ based on PHP conditions)::
     // src/Repository/ProductRepository.php
 
     // ...
-    public function findAllGreaterThanPrice($price, $includeUnavailableProducts = false): array
+    class ProductRepository extends ServiceEntityRepository
     {
-        // automatically knows to select Products
-        // the "p" is an alias you'll use in the rest of the query
-        $qb = $this->createQueryBuilder('p')
-            ->where('p.price > :price')
-            ->setParameter('price', $price)
-            ->orderBy('p.price', 'ASC');
-
-        if (!$includeUnavailableProducts) {
-            $qb->andWhere('p.available = TRUE');
-        }
+        public function findAllGreaterThanPrice(int $price, bool $includeUnavailableProducts = false): array
+        {
+            // automatically knows to select Products
+            // the "p" is an alias you'll use in the rest of the query
+            $qb = $this->createQueryBuilder('p')
+                ->where('p.price > :price')
+                ->setParameter('price', $price)
+                ->orderBy('p.price', 'ASC');
+
+            if (!$includeUnavailableProducts) {
+                $qb->andWhere('p.available = TRUE');
+            }
 
-        $query = $qb->getQuery();
+            $query = $qb->getQuery();
 
-        return $query->execute();
+            return $query->execute();
 
-        // to get just one result:
-        // $product = $query->setMaxResults(1)->getOneOrNullResult();
+            // to get just one result:
+            // $product = $query->setMaxResults(1)->getOneOrNullResult();
+        }
     }
 
 Querying with SQL
@@ -802,20 +838,23 @@ In addition, you can query directly with SQL if you need to::
     // src/Repository/ProductRepository.php
 
     // ...
-    public function findAllGreaterThanPrice($price): array
+    class ProductRepository extends ServiceEntityRepository
     {
-        $conn = $this->getEntityManager()->getConnection();
-
-        $sql = '
-            SELECT * FROM product p
-            WHERE p.price > :price
-            ORDER BY p.price ASC
-            ';
-        $stmt = $conn->prepare($sql);
-        $stmt->execute(['price' => $price]);
-
-        // returns an array of arrays (i.e. a raw data set)
-        return $stmt->fetchAllAssociative();
+        public function findAllGreaterThanPrice(int $price): array
+        {
+            $conn = $this->getEntityManager()->getConnection();
+
+            $sql = '
+                SELECT * FROM product p
+                WHERE p.price > :price
+                ORDER BY p.price ASC
+                ';
+            $stmt = $conn->prepare($sql);
+            $stmt->execute(['price' => $price]);
+
+            // returns an array of arrays (i.e. a raw data set)
+            return $stmt->fetchAllAssociative();
+        }
     }
 
 With SQL, you will get back raw data, not objects (unless you use the `NativeQuery`_
diff --git a/doctrine/associations.rst b/doctrine/associations.rst
index 8bdddab536b..4a2fafb6467 100644
--- a/doctrine/associations.rst
+++ b/doctrine/associations.rst
@@ -327,7 +327,7 @@ Now you can see this new code in action! Imagine you're inside a controller::
         /**
          * @Route("/product", name="product")
          */
-        public function index()
+        public function index(): Response
         {
             $category = new Category();
             $category->setName('Computer Peripherals');
@@ -378,20 +378,26 @@ When you need to fetch associated objects, your workflow looks like it did
 before. First, fetch a ``$product`` object and then access its related
 ``Category`` object::
 
+    // src/Controller/ProductController.php
+    namespace App\Controller;
+
     use App\Entity\Product;
     // ...
 
-    public function show($id)
+    class ProductController extends AbstractController
     {
-        $product = $this->getDoctrine()
-            ->getRepository(Product::class)
-            ->find($id);
+        public function show(int $id): Response
+        {
+            $product = $this->getDoctrine()
+                ->getRepository(Product::class)
+                ->find($id);
 
-        // ...
+            // ...
 
-        $categoryName = $product->getCategory()->getName();
+            $categoryName = $product->getCategory()->getName();
 
-        // ...
+            // ...
+        }
     }
 
 In this example, you first query for a ``Product`` object based on the product's
@@ -411,15 +417,21 @@ the category (i.e. it's "lazily loaded").
 Because we mapped the optional ``OneToMany`` side, you can also query in the other
 direction::
 
-    public function showProducts($id)
+    // src/Controller/ProductController.php
+
+    // ...
+    class ProductController extends AbstractController
     {
-        $category = $this->getDoctrine()
-            ->getRepository(Category::class)
-            ->find($id);
+        public function showProducts(int $id): Response
+        {
+            $category = $this->getDoctrine()
+                ->getRepository(Category::class)
+                ->find($id);
 
-        $products = $category->getProducts();
+            $products = $category->getProducts();
 
-        // ...
+            // ...
+        }
     }
 
 In this case, the same things occur: you first query for a single ``Category``
@@ -475,18 +487,23 @@ can avoid the second query by issuing a join in the original query. Add the
 following method to the ``ProductRepository`` class::
 
     // src/Repository/ProductRepository.php
-    public function findOneByIdJoinedToCategory($productId)
+
+    // ...
+    class ProductRepository extends ServiceEntityRepository
     {
-        $entityManager = $this->getEntityManager();
+        public function findOneByIdJoinedToCategory(int $productId): ?Product
+        {
+            $entityManager = $this->getEntityManager();
 
-        $query = $entityManager->createQuery(
-            'SELECT p, c
-            FROM App\Entity\Product p
-            INNER JOIN p.category c
-            WHERE p.id = :id'
-        )->setParameter('id', $productId);
+            $query = $entityManager->createQuery(
+                'SELECT p, c
+                FROM App\Entity\Product p
+                INNER JOIN p.category c
+                WHERE p.id = :id'
+            )->setParameter('id', $productId);
 
-        return $query->getOneOrNullResult();
+            return $query->getOneOrNullResult();
+        }
     }
 
 This will *still* return an array of ``Product`` objects. But now, when you call
@@ -495,15 +512,21 @@ This will *still* return an array of ``Product`` objects. But now, when you call
 Now, you can use this method in your controller to query for a ``Product``
 object and its related ``Category`` in one query::
 
-    public function show($id)
+    // src/Controller/ProductController.php
+
+    // ...
+    class ProductController extends AbstractController
     {
-        $product = $this->getDoctrine()
-            ->getRepository(Product::class)
-            ->findOneByIdJoinedToCategory($id);
+        public function show(int $id): Response
+        {
+            $product = $this->getDoctrine()
+                ->getRepository(Product::class)
+                ->findOneByIdJoinedToCategory($id);
 
-        $category = $product->getCategory();
+            $category = $product->getCategory();
 
-        // ...
+            // ...
+        }
     }
 
 .. _associations-inverse-side:
diff --git a/doctrine/dbal.rst b/doctrine/dbal.rst
index 3ddb98d837f..80c145d3d6a 100644
--- a/doctrine/dbal.rst
+++ b/doctrine/dbal.rst
@@ -48,10 +48,12 @@ object::
     namespace App\Controller;
 
     use Doctrine\DBAL\Driver\Connection;
+    use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+    use Symfony\Component\HttpFoundation\Response;
 
     class UserController extends AbstractController
     {
-        public function index(Connection $connection)
+        public function index(Connection $connection): Response
         {
             $users = $connection->fetchAll('SELECT * FROM users');
 
diff --git a/doctrine/events.rst b/doctrine/events.rst
index 1ce0bfa8ac0..309d10a7e12 100644
--- a/doctrine/events.rst
+++ b/doctrine/events.rst
@@ -74,7 +74,7 @@ define a callback for the ``prePersist`` Doctrine event:
             /**
              * @ORM\PrePersist
              */
-            public function setCreatedAtValue()
+            public function setCreatedAtValue(): void
             {
                 $this->createdAt = new \DateTime();
             }
@@ -132,7 +132,7 @@ do so, define a listener for the ``postPersist`` Doctrine event::
     {
         // the listener methods receive an argument which gives you access to
         // both the entity object of the event and the entity manager itself
-        public function postPersist(LifecycleEventArgs $args)
+        public function postPersist(LifecycleEventArgs $args): void
         {
             $entity = $args->getObject();
 
@@ -241,7 +241,7 @@ define a listener for the ``postUpdate`` Doctrine event::
     {
         // the entity listener methods receive two arguments:
         // the entity instance and the lifecycle event
-        public function postUpdate(User $user, LifecycleEventArgs $event)
+        public function postUpdate(User $user, LifecycleEventArgs $event): void
         {
             // ... do something to notify the changes
         }
@@ -365,7 +365,7 @@ want to log all the database activity. To do so, define a subscriber for the
     {
         // this method can only return the event names; you cannot define a
         // custom method name to execute when each event triggers
-        public function getSubscribedEvents()
+        public function getSubscribedEvents(): array
         {
             return [
                 Events::postPersist,
@@ -377,22 +377,22 @@ want to log all the database activity. To do so, define a subscriber for the
         // callback methods must be called exactly like the events they listen to;
         // they receive an argument of type LifecycleEventArgs, which gives you access
         // to both the entity object of the event and the entity manager itself
-        public function postPersist(LifecycleEventArgs $args)
+        public function postPersist(LifecycleEventArgs $args): void
         {
             $this->logActivity('persist', $args);
         }
 
-        public function postRemove(LifecycleEventArgs $args)
+        public function postRemove(LifecycleEventArgs $args): void
         {
             $this->logActivity('remove', $args);
         }
 
-        public function postUpdate(LifecycleEventArgs $args)
+        public function postUpdate(LifecycleEventArgs $args): void
         {
             $this->logActivity('update', $args);
         }
 
-        private function logActivity(string $action, LifecycleEventArgs $args)
+        private function logActivity(string $action, LifecycleEventArgs $args): void
         {
             $entity = $args->getObject();
 
diff --git a/doctrine/multiple_entity_managers.rst b/doctrine/multiple_entity_managers.rst
index faffc480877..ba3475dbfbc 100644
--- a/doctrine/multiple_entity_managers.rst
+++ b/doctrine/multiple_entity_managers.rst
@@ -234,12 +234,11 @@ the default entity manager (i.e. ``default``) is returned::
     namespace App\Controller;
 
     // ...
-
     use Doctrine\ORM\EntityManagerInterface;
 
     class UserController extends AbstractController
     {
-        public function index(EntityManagerInterface $entityManager)
+        public function index(EntityManagerInterface $entityManager): Response
         {
             // These methods also return the default entity manager, but it's preferred
             // to get it by injecting EntityManagerInterface in the action method
@@ -250,6 +249,8 @@ the default entity manager (i.e. ``default``) is returned::
             // Both of these return the "customer" entity manager
             $customerEntityManager = $this->getDoctrine()->getManager('customer');
             $customerEntityManager = $this->get('doctrine.orm.customer_entity_manager');
+
+            // ...
         }
     }
 
@@ -268,7 +269,7 @@ The same applies to repository calls::
 
     class UserController extends AbstractController
     {
-        public function index()
+        public function index(): Response
         {
             // Retrieves a repository managed by the "default" em
             $products = $this->getDoctrine()
@@ -287,6 +288,8 @@ The same applies to repository calls::
                 ->getRepository(Customer::class, 'customer')
                 ->findAll()
             ;
+
+            // ...
         }
     }
 
diff --git a/doctrine/resolve_target_entity.rst b/doctrine/resolve_target_entity.rst
index 36038fd9f3c..765f5d187ce 100644
--- a/doctrine/resolve_target_entity.rst
+++ b/doctrine/resolve_target_entity.rst
@@ -96,10 +96,7 @@ An InvoiceSubjectInterface::
         // will need to access on the subject so that you can
         // be sure that you have access to those methods.
 
-        /**
-         * @return string
-         */
-        public function getName();
+        public function getName(): string;
     }
 
 Next, you need to configure the listener, which tells the DoctrineBundle

From aec1016d94db1de37eaedb7f8567046168d0805a Mon Sep 17 00:00:00 2001
From: Wouter de Jong <wouter@wouterj.nl>
Date: Sun, 8 Nov 2020 14:57:22 +0100
Subject: [PATCH 2/3] Added PHP types to the Form related articles

---
 form/create_custom_field_type.rst          |  18 ++--
 form/create_form_type_extension.rst        |   8 +-
 form/data_based_validation.rst             |   6 +-
 form/data_mappers.rst                      |   8 +-
 form/data_transformers.rst                 |  28 +++---
 form/direct_submit.rst                     |   3 +-
 form/disabling_validation.rst              |   2 +-
 form/dynamic_form_modification.rst         |  31 ++++---
 form/embedded.rst                          |  10 +-
 form/events.rst                            |  10 +-
 form/form_collections.rst                  | 102 +++++++++++----------
 form/form_themes.rst                       |  10 +-
 form/inherit_data_option.rst               |  12 +--
 form/type_guesser.rst                      |  14 +--
 form/use_empty_data.rst                    |   6 +-
 form/validation_group_service_resolver.rst |   8 +-
 form/validation_groups.rst                 |   2 +-
 form/without_class.rst                     |  43 +++++----
 forms.rst                                  | 100 +++++++++++---------
 19 files changed, 224 insertions(+), 197 deletions(-)

diff --git a/form/create_custom_field_type.rst b/form/create_custom_field_type.rst
index 58e265fd2ad..59816006041 100644
--- a/form/create_custom_field_type.rst
+++ b/form/create_custom_field_type.rst
@@ -38,7 +38,7 @@ By convention they are stored in the ``src/Form/Type/`` directory::
 
     class ShippingType extends AbstractType
     {
-        public function configureOptions(OptionsResolver $resolver)
+        public function configureOptions(OptionsResolver $resolver): void
         {
             $resolver->setDefaults([
                 'choices' => [
@@ -49,7 +49,7 @@ By convention they are stored in the ``src/Form/Type/`` directory::
             ]);
         }
 
-        public function getParent()
+        public function getParent(): string
         {
             return ChoiceType::class;
         }
@@ -82,7 +82,7 @@ Now you can add this form type when :doc:`creating Symfony forms </forms>`::
 
     class OrderType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 // ...
@@ -168,7 +168,7 @@ in the postal address. For the moment, all fields are of type ``TextType``::
     {
         // ...
 
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 ->add('addressLine1', TextType::class, [
@@ -209,7 +209,7 @@ correctly rendered in any template::
 
     class OrderType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 // ...
@@ -254,7 +254,7 @@ to define, validate and process their values::
     {
         // ...
 
-        public function configureOptions(OptionsResolver $resolver)
+        public function configureOptions(OptionsResolver $resolver): void
         {
             // this defines the available options and their default values when
             // they are not configured explicitly when using the form type
@@ -293,7 +293,7 @@ Now you can configure these options when using the form type::
 
     class OrderType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 // ...
@@ -320,7 +320,7 @@ The last step is to use these options when building the form::
     {
         // ...
 
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             // ...
 
@@ -473,7 +473,7 @@ defined by the form or be completely independent::
 
         // ...
 
-        public function buildView(FormView $view, FormInterface $form, array $options)
+        public function buildView(FormView $view, FormInterface $form, array $options): void
         {
             // pass the form type option directly to the template
             $view->vars['isExtendedAddress'] = $options['is_extended_address'];
diff --git a/form/create_form_type_extension.rst b/form/create_form_type_extension.rst
index 59b1c06e9fe..55d3d34776f 100644
--- a/form/create_form_type_extension.rst
+++ b/form/create_form_type_extension.rst
@@ -114,7 +114,7 @@ the database::
 
         // ...
 
-        public function getWebPath()
+        public function getWebPath(): string
         {
             // ... $webPath being the full image URL, to be used in templates
 
@@ -149,13 +149,13 @@ For example::
             return [FileType::class];
         }
 
-        public function configureOptions(OptionsResolver $resolver)
+        public function configureOptions(OptionsResolver $resolver): void
         {
             // makes it legal for FileType fields to have an image_property option
             $resolver->setDefined(['image_property']);
         }
 
-        public function buildView(FormView $view, FormInterface $form, array $options)
+        public function buildView(FormView $view, FormInterface $form, array $options): void
         {
             if (isset($options['image_property'])) {
                 // this will be whatever class/entity is bound to your form (e.g. Media)
@@ -221,7 +221,7 @@ next to the file field. For example::
 
     class MediaType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 ->add('name', TextType::class)
diff --git a/form/data_based_validation.rst b/form/data_based_validation.rst
index 383883ba91f..226284db439 100644
--- a/form/data_based_validation.rst
+++ b/form/data_based_validation.rst
@@ -12,7 +12,7 @@ to an array callback::
     use Symfony\Component\OptionsResolver\OptionsResolver;
 
     // ...
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'validation_groups' => [
@@ -32,7 +32,7 @@ example).  You can also define whole logic inline by using a ``Closure``::
     use Symfony\Component\OptionsResolver\OptionsResolver;
 
     // ...
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'validation_groups' => function (FormInterface $form) {
@@ -56,7 +56,7 @@ of the entity as well you have to adjust the option as follows::
     use Symfony\Component\OptionsResolver\OptionsResolver;
 
     // ...
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'validation_groups' => function (FormInterface $form) {
diff --git a/form/data_mappers.rst b/form/data_mappers.rst
index 15e66ce54b3..c14eabd7683 100644
--- a/form/data_mappers.rst
+++ b/form/data_mappers.rst
@@ -98,7 +98,7 @@ in your form type::
         /**
          * @param Color|null $viewData
          */
-        public function mapDataToForms($viewData, $forms)
+        public function mapDataToForms($viewData, $forms): void
         {
             // there is no data yet, so nothing to prepopulate
             if (null === $viewData) {
@@ -119,7 +119,7 @@ in your form type::
             $forms['blue']->setData($viewData->getBlue());
         }
 
-        public function mapFormsToData($forms, &$viewData)
+        public function mapFormsToData($forms, &$viewData): void
         {
             /** @var FormInterface[] $forms */
             $forms = iterator_to_array($forms);
@@ -158,7 +158,7 @@ method::
 
     final class ColorType extends AbstractType implements DataMapperInterface
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 ->add('red', IntegerType::class, [
@@ -177,7 +177,7 @@ method::
             ;
         }
 
-        public function configureOptions(OptionsResolver $resolver)
+        public function configureOptions(OptionsResolver $resolver): void
         {
             // when creating a new color, the initial data should be null
             $resolver->setDefault('empty_data', null);
diff --git a/form/data_transformers.rst b/form/data_transformers.rst
index 4a087a0aaff..aa0e88789bf 100644
--- a/form/data_transformers.rst
+++ b/form/data_transformers.rst
@@ -40,12 +40,12 @@ Suppose you have a Task form with a tags ``text`` type::
     // ...
     class TaskType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder->add('tags', TextType::class);
         }
 
-        public function configureOptions(OptionsResolver $resolver)
+        public function configureOptions(OptionsResolver $resolver): void
         {
             $resolver->setDefaults([
                 'data_class' => Task::class,
@@ -72,7 +72,7 @@ class::
 
     class TaskType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder->add('tags', TextType::class);
 
@@ -136,7 +136,7 @@ Start by setting up the text field like normal::
     // ...
     class TaskType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 ->add('description', TextareaType::class)
@@ -144,7 +144,7 @@ Start by setting up the text field like normal::
             ;
         }
 
-        public function configureOptions(OptionsResolver $resolver)
+        public function configureOptions(OptionsResolver $resolver): void
         {
             $resolver->setDefaults([
                 'data_class' => Task::class,
@@ -188,9 +188,8 @@ to and from the issue number and the ``Issue`` object::
          * Transforms an object (issue) to a string (number).
          *
          * @param  Issue|null $issue
-         * @return string
          */
-        public function transform($issue)
+        public function transform($issue): string
         {
             if (null === $issue) {
                 return '';
@@ -203,10 +202,9 @@ to and from the issue number and the ``Issue`` object::
          * Transforms a string (number) to an object (issue).
          *
          * @param  string $issueNumber
-         * @return Issue|null
          * @throws TransformationFailedException if object (issue) is not found.
          */
-        public function reverseTransform($issueNumber)
+        public function reverseTransform($issueNumber): ?Issue
         {
             // no issue number? It's optional, so that's ok
             if (!$issueNumber) {
@@ -273,7 +271,7 @@ and type-hint the new class::
             $this->transformer = $transformer;
         }
 
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 ->add('description', TextareaType::class)
@@ -306,7 +304,7 @@ end-user error message in the data transformer using the
     {
         // ...
 
-        public function reverseTransform($issueNumber)
+        public function reverseTransform($issueNumber): ?Issue
         {
             // ...
 
@@ -394,19 +392,19 @@ First, create the custom field type class::
             $this->transformer = $transformer;
         }
 
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder->addModelTransformer($this->transformer);
         }
 
-        public function configureOptions(OptionsResolver $resolver)
+        public function configureOptions(OptionsResolver $resolver): void
         {
             $resolver->setDefaults([
                 'invalid_message' => 'The selected issue does not exist',
             ]);
         }
 
-        public function getParent()
+        public function getParent(): string
         {
             return TextType::class;
         }
@@ -427,7 +425,7 @@ As long as you're using :ref:`autowire <services-autowire>` and
 
     class TaskType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 ->add('description', TextareaType::class)
diff --git a/form/direct_submit.rst b/form/direct_submit.rst
index ef6897611ad..876ad3964b1 100644
--- a/form/direct_submit.rst
+++ b/form/direct_submit.rst
@@ -11,9 +11,10 @@ to detect when the form has been submitted. However, you can also use the
 control over when exactly your form is submitted and what data is passed to it::
 
     use Symfony\Component\HttpFoundation\Request;
+    use Symfony\Component\HttpFoundation\Response;
     // ...
 
-    public function new(Request $request)
+    public function new(Request $request): Response
     {
         $task = new Task();
         $form = $this->createForm(TaskType::class, $task);
diff --git a/form/disabling_validation.rst b/form/disabling_validation.rst
index f23cc73dbbf..2844d0c865d 100644
--- a/form/disabling_validation.rst
+++ b/form/disabling_validation.rst
@@ -9,7 +9,7 @@ these cases you can set the ``validation_groups`` option to ``false``::
 
     use Symfony\Component\OptionsResolver\OptionsResolver;
 
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'validation_groups' => false,
diff --git a/form/dynamic_form_modification.rst b/form/dynamic_form_modification.rst
index 69339480248..279b5b4118d 100644
--- a/form/dynamic_form_modification.rst
+++ b/form/dynamic_form_modification.rst
@@ -45,13 +45,13 @@ a bare form class looks like::
 
     class ProductType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder->add('name');
             $builder->add('price');
         }
 
-        public function configureOptions(OptionsResolver $resolver)
+        public function configureOptions(OptionsResolver $resolver): void
         {
             $resolver->setDefaults([
                 'data_class' => Product::class,
@@ -92,7 +92,7 @@ creating that particular field is delegated to an event listener::
 
     class ProductType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder->add('price');
 
@@ -109,7 +109,7 @@ object is new (e.g. hasn't been persisted to the database). Based on that,
 the event listener might look like the following::
 
     // ...
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         // ...
         $builder->addEventListener(FormEvents::PRE_SET_DATA, function (FormEvent $event) {
@@ -151,14 +151,14 @@ you can also move the logic for creating the ``name`` field to an
 
     class AddNameFieldSubscriber implements EventSubscriberInterface
     {
-        public static function getSubscribedEvents()
+        public static function getSubscribedEvents(): array
         {
             // Tells the dispatcher that you want to listen on the form.pre_set_data
             // event and that the preSetData method should be called.
             return [FormEvents::PRE_SET_DATA => 'preSetData'];
         }
 
-        public function preSetData(FormEvent $event)
+        public function preSetData(FormEvent $event): void
         {
             $product = $event->getData();
             $form = $event->getForm();
@@ -179,7 +179,7 @@ Great! Now use that in your form class::
 
     class ProductType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder->add('price');
 
@@ -217,7 +217,7 @@ Using an event listener, your form might look like this::
 
     class FriendMessageFormType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 ->add('subject', TextType::class)
@@ -274,7 +274,7 @@ security helper to fill in the listener logic::
             $this->security = $security;
         }
 
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 ->add('subject', TextType::class)
@@ -337,10 +337,12 @@ and :doc:`tag it </service_container/tags>` with the ``form.type`` tag.
 In a controller, create the form like normal::
 
     use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+    use Symfony\Component\HttpFoundation\Request;
+    use Symfony\Component\HttpFoundation\Response;
 
     class FriendMessageController extends AbstractController
     {
-        public function new(Request $request)
+        public function new(Request $request): Response
         {
             $form = $this->createForm(FriendMessageFormType::class);
 
@@ -351,7 +353,7 @@ In a controller, create the form like normal::
 You can also  embed the form type into another form::
 
     // inside some other "form type" class
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder->add('message', FriendMessageFormType::class);
     }
@@ -384,7 +386,7 @@ sport like this::
 
     class SportMeetupType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 ->add('sport', EntityType::class, [
@@ -448,7 +450,7 @@ The type would now look like::
 
     class SportMeetupType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 ->add('sport', EntityType::class, [
@@ -515,11 +517,12 @@ your application. Assume that you have a sport meetup creation controller::
     use App\Form\Type\SportMeetupType;
     use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
     use Symfony\Component\HttpFoundation\Request;
+    use Symfony\Component\HttpFoundation\Response;
     // ...
 
     class MeetupController extends AbstractController
     {
-        public function create(Request $request)
+        public function create(Request $request): Response
         {
             $meetup = new SportMeetup();
             $form = $this->createForm(SportMeetupType::class, $meetup);
diff --git a/form/embedded.rst b/form/embedded.rst
index 9da8104b143..787580a41d1 100644
--- a/form/embedded.rst
+++ b/form/embedded.rst
@@ -46,12 +46,12 @@ Next, add a new ``category`` property to the ``Task`` class::
 
         // ...
 
-        public function getCategory()
+        public function getCategory(): ?Category
         {
             return $this->category;
         }
 
-        public function setCategory(Category $category = null)
+        public function setCategory(?Category $category)
         {
             $this->category = $category;
         }
@@ -76,12 +76,12 @@ create a form class so that a ``Category`` object can be modified by the user::
 
     class CategoryType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder->add('name');
         }
 
-        public function configureOptions(OptionsResolver $resolver)
+        public function configureOptions(OptionsResolver $resolver): void
         {
             $resolver->setDefaults([
                 'data_class' => Category::class,
@@ -97,7 +97,7 @@ class::
     use App\Form\CategoryType;
     use Symfony\Component\Form\FormBuilderInterface;
 
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         // ...
 
diff --git a/form/events.rst b/form/events.rst
index 5620ec96f46..0f2e26e2775 100644
--- a/form/events.rst
+++ b/form/events.rst
@@ -308,7 +308,7 @@ callback for better readability::
     // ...
     class SubscriptionType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 ->add('username', TextType::class)
@@ -320,7 +320,7 @@ callback for better readability::
             ;
         }
 
-        public function onPreSetData(FormEvent $event)
+        public function onPreSetData(FormEvent $event): void
         {
             // ...
         }
@@ -347,7 +347,7 @@ Consider the following example of a form event subscriber::
 
     class AddEmailFieldListener implements EventSubscriberInterface
     {
-        public static function getSubscribedEvents()
+        public static function getSubscribedEvents(): array
         {
             return [
                 FormEvents::PRE_SET_DATA => 'onPreSetData',
@@ -355,7 +355,7 @@ Consider the following example of a form event subscriber::
             ];
         }
 
-        public function onPreSetData(FormEvent $event)
+        public function onPreSetData(FormEvent $event): void
         {
             $user = $event->getData();
             $form = $event->getForm();
@@ -367,7 +367,7 @@ Consider the following example of a form event subscriber::
             }
         }
 
-        public function onPreSubmit(FormEvent $event)
+        public function onPreSubmit(FormEvent $event): void
         {
             $user = $event->getData();
             $form = $event->getForm();
diff --git a/form/form_collections.rst b/form/form_collections.rst
index 405ffed53e4..cd1f66a7a8f 100644
--- a/form/form_collections.rst
+++ b/form/form_collections.rst
@@ -15,6 +15,7 @@ Let's start by creating a ``Task`` entity::
     namespace App\Entity;
 
     use Doctrine\Common\Collections\ArrayCollection;
+    use Doctrine\Common\Collections\Collection;
 
     class Task
     {
@@ -26,17 +27,17 @@ Let's start by creating a ``Task`` entity::
             $this->tags = new ArrayCollection();
         }
 
-        public function getDescription()
+        public function getDescription(): string
         {
             return $this->description;
         }
 
-        public function setDescription($description)
+        public function setDescription(string $description): void
         {
             $this->description = $description;
         }
 
-        public function getTags()
+        public function getTags(): Collection
         {
             return $this->tags;
         }
@@ -58,12 +59,12 @@ objects::
     {
         private $name;
 
-        public function getName()
+        public function getName(): string
         {
             return $this->name;
         }
 
-        public function setName($name)
+        public function setName(string $name): void
         {
             $this->name = $name;
         }
@@ -81,12 +82,12 @@ Then, create a form class so that a ``Tag`` object can be modified by the user::
 
     class TagType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder->add('name');
         }
 
-        public function configureOptions(OptionsResolver $resolver)
+        public function configureOptions(OptionsResolver $resolver): void
         {
             $resolver->setDefaults([
                 'data_class' => Tag::class,
@@ -110,7 +111,7 @@ inside the task form itself::
 
     class TaskType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder->add('description');
 
@@ -120,7 +121,7 @@ inside the task form itself::
             ]);
         }
 
-        public function configureOptions(OptionsResolver $resolver)
+        public function configureOptions(OptionsResolver $resolver): void
         {
             $resolver->setDefaults([
                 'data_class' => Task::class,
@@ -138,10 +139,11 @@ In your controller, you'll create a new form from the ``TaskType``::
     use App\Form\TaskType;
     use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
     use Symfony\Component\HttpFoundation\Request;
+    use Symfony\Component\HttpFoundation\Response;
 
     class TaskController extends AbstractController
     {
-        public function new(Request $request)
+        public function new(Request $request): Response
         {
             $task = new Task();
 
@@ -224,7 +226,7 @@ it will receive an *unknown* number of tags. Otherwise, you'll see a
 
     // ...
 
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         // ...
 
@@ -367,12 +369,12 @@ for the tags in the ``Task`` class::
     {
         // ...
 
-        public function addTag(Tag $tag)
+        public function addTag(Tag $tag): void
         {
             $this->tags->add($tag);
         }
 
-        public function removeTag(Tag $tag)
+        public function removeTag(Tag $tag): void
         {
             // ...
         }
@@ -383,7 +385,7 @@ Next, add a ``by_reference`` option to the ``tags`` field and set it to ``false`
     // src/Form/TaskType.php
 
     // ...
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         // ...
 
@@ -484,7 +486,7 @@ you will learn about next!).
         // src/Entity/Task.php
 
         // ...
-        public function addTag(Tag $tag)
+        public function addTag(Tag $tag): void
         {
             // for a many-to-many association:
             $tag->addTask($this);
@@ -501,7 +503,7 @@ you will learn about next!).
         // src/Entity/Tag.php
 
         // ...
-        public function addTask(Task $task)
+        public function addTask(Task $task): void
         {
             if (!$this->tasks->contains($task)) {
                 $this->tasks->add($task);
@@ -521,7 +523,7 @@ Start by adding the ``allow_delete`` option in the form Type::
     // src/Form/TaskType.php
 
     // ...
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         // ...
 
@@ -540,7 +542,7 @@ Now, you need to put some code into the ``removeTag()`` method of ``Task``::
     {
         // ...
 
-        public function removeTag(Tag $tag)
+        public function removeTag(Tag $tag): void
         {
             $this->tags->removeElement($tag);
         }
@@ -617,52 +619,56 @@ the relationship between the removed ``Tag`` and ``Task`` object.
     is handling the "update" of your Task::
 
         // src/Controller/TaskController.php
+
+        // ...
         use App\Entity\Task;
         use Doctrine\Common\Collections\ArrayCollection;
 
-        // ...
-        public function edit($id, Request $request, EntityManagerInterface $entityManager)
+        class TaskController extends AbstractController
         {
-            if (null === $task = $entityManager->getRepository(Task::class)->find($id)) {
-                throw $this->createNotFoundException('No task found for id '.$id);
-            }
+            public function edit($id, Request $request, EntityManagerInterface $entityManager): Response
+            {
+                if (null === $task = $entityManager->getRepository(Task::class)->find($id)) {
+                    throw $this->createNotFoundException('No task found for id '.$id);
+                }
 
-            $originalTags = new ArrayCollection();
+                $originalTags = new ArrayCollection();
 
-            // Create an ArrayCollection of the current Tag objects in the database
-            foreach ($task->getTags() as $tag) {
-                $originalTags->add($tag);
-            }
+                // Create an ArrayCollection of the current Tag objects in the database
+                foreach ($task->getTags() as $tag) {
+                    $originalTags->add($tag);
+                }
 
-            $editForm = $this->createForm(TaskType::class, $task);
+                $editForm = $this->createForm(TaskType::class, $task);
 
-            $editForm->handleRequest($request);
+                $editForm->handleRequest($request);
 
-            if ($editForm->isSubmitted() && $editForm->isValid()) {
-                // remove the relationship between the tag and the Task
-                foreach ($originalTags as $tag) {
-                    if (false === $task->getTags()->contains($tag)) {
-                        // remove the Task from the Tag
-                        $tag->getTasks()->removeElement($task);
+                if ($editForm->isSubmitted() && $editForm->isValid()) {
+                    // remove the relationship between the tag and the Task
+                    foreach ($originalTags as $tag) {
+                        if (false === $task->getTags()->contains($tag)) {
+                            // remove the Task from the Tag
+                            $tag->getTasks()->removeElement($task);
 
-                        // if it was a many-to-one relationship, remove the relationship like this
-                        // $tag->setTask(null);
+                            // if it was a many-to-one relationship, remove the relationship like this
+                            // $tag->setTask(null);
 
-                        $entityManager->persist($tag);
+                            $entityManager->persist($tag);
 
-                        // if you wanted to delete the Tag entirely, you can also do that
-                        // $entityManager->remove($tag);
+                            // if you wanted to delete the Tag entirely, you can also do that
+                            // $entityManager->remove($tag);
+                        }
                     }
-                }
 
-                $entityManager->persist($task);
-                $entityManager->flush();
+                    $entityManager->persist($task);
+                    $entityManager->flush();
 
-                // redirect back to some edit page
-                return $this->redirectToRoute('task_edit', ['id' => $id]);
-            }
+                    // redirect back to some edit page
+                    return $this->redirectToRoute('task_edit', ['id' => $id]);
+                }
 
-            // render some form template
+                // ... render some form template
+            }
         }
 
     As you can see, adding and removing the elements correctly can be tricky.
diff --git a/form/form_themes.rst b/form/form_themes.rst
index 3811b042c28..1b5a3594a2d 100644
--- a/form/form_themes.rst
+++ b/form/form_themes.rst
@@ -266,7 +266,7 @@ form. You can also define this value explicitly with the ``block_name`` option::
     use Symfony\Component\Form\Extension\Core\Type\TextType;
     use Symfony\Component\Form\FormBuilderInterface;
 
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         // ...
 
@@ -290,7 +290,7 @@ field without having to :doc:`create a custom form type </form/create_custom_fie
     use Symfony\Component\Form\Extension\Core\Type\TextType;
     use Symfony\Component\Form\FormBuilderInterface;
 
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder->add('name', TextType::class, [
             'block_prefix' => 'wrapped_text',
@@ -316,7 +316,7 @@ following complex example where a ``TaskManagerType`` has a collection of
 
     class TaskManagerType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options = [])
+        public function buildForm(FormBuilderInterface $builder, array $options = []): void
         {
             // ...
             $builder->add('taskLists', CollectionType::class, [
@@ -328,7 +328,7 @@ following complex example where a ``TaskManagerType`` has a collection of
 
     class TaskListType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options = [])
+        public function buildForm(FormBuilderInterface $builder, array $options = []): void
         {
             // ...
             $builder->add('tasks', CollectionType::class, [
@@ -339,7 +339,7 @@ following complex example where a ``TaskManagerType`` has a collection of
 
     class TaskType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options = [])
+        public function buildForm(FormBuilderInterface $builder, array $options = []): void
         {
             $builder->add('name');
             // ...
diff --git a/form/inherit_data_option.rst b/form/inherit_data_option.rst
index 3321ab2153a..f4161a21111 100644
--- a/form/inherit_data_option.rst
+++ b/form/inherit_data_option.rst
@@ -52,7 +52,7 @@ Start with building two forms for these entities, ``CompanyType`` and ``Customer
 
     class CompanyType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 ->add('name', TextType::class)
@@ -71,7 +71,7 @@ Start with building two forms for these entities, ``CompanyType`` and ``Customer
 
     class CustomerType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 ->add('firstName', TextType::class)
@@ -94,7 +94,7 @@ for that::
 
     class LocationType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 ->add('address', TextareaType::class)
@@ -103,7 +103,7 @@ for that::
                 ->add('country', TextType::class);
         }
 
-        public function configureOptions(OptionsResolver $resolver)
+        public function configureOptions(OptionsResolver $resolver): void
         {
             $resolver->setDefaults([
                 'inherit_data' => true,
@@ -131,7 +131,7 @@ Finally, make this work by adding the location form to your two original forms::
     use App\Entity\Company;
     // ...
 
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         // ...
 
@@ -148,7 +148,7 @@ Finally, make this work by adding the location form to your two original forms::
     use App\Entity\Customer;
     // ...
 
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         // ...
 
diff --git a/form/type_guesser.rst b/form/type_guesser.rst
index f990aad4115..49488e524ba 100644
--- a/form/type_guesser.rst
+++ b/form/type_guesser.rst
@@ -40,22 +40,24 @@ Start by creating the class and these methods. Next, you'll learn how to fill ea
     namespace App\Form\TypeGuesser;
 
     use Symfony\Component\Form\FormTypeGuesserInterface;
+    use Symfony\Component\Form\Guess\TypeGuess;
+    use Symfony\Component\Form\Guess\ValueGuess;
 
     class PHPDocTypeGuesser implements FormTypeGuesserInterface
     {
-        public function guessType($class, $property)
+        public function guessType($class, $property): ?TypeGuess
         {
         }
 
-        public function guessRequired($class, $property)
+        public function guessRequired($class, $property): ?ValueGuess
         {
         }
 
-        public function guessMaxLength($class, $property)
+        public function guessMaxLength($class, $property): ?ValueGuess
         {
         }
 
-        public function guessPattern($class, $property)
+        public function guessPattern($class, $property): ?ValueGuess
         {
         }
     }
@@ -94,7 +96,7 @@ With this knowledge, you can implement the ``guessType()`` method of the
 
     class PHPDocTypeGuesser implements FormTypeGuesserInterface
     {
-        public function guessType($class, $property)
+        public function guessType($class, $property): ?TypeGuess
         {
             $annotations = $this->readPhpDocAnnotations($class, $property);
 
@@ -129,7 +131,7 @@ With this knowledge, you can implement the ``guessType()`` method of the
             }
         }
 
-        protected function readPhpDocAnnotations($class, $property)
+        protected function readPhpDocAnnotations(string $class, string $property): array
         {
             $reflectionProperty = new \ReflectionProperty($class, $property);
             $phpdoc = $reflectionProperty->getDocComment();
diff --git a/form/use_empty_data.rst b/form/use_empty_data.rst
index 6a567286094..c2cba15ad7f 100644
--- a/form/use_empty_data.rst
+++ b/form/use_empty_data.rst
@@ -9,7 +9,7 @@ form class. This empty data set would be used if you submit your form, but
 haven't called ``setData()`` on your form or passed in data when you created
 your form. For example, in a controller::
 
-    public function index()
+    public function index(): Response
     {
         $blog = ...;
 
@@ -61,7 +61,7 @@ that constructor with no arguments::
         }
         // ...
 
-        public function configureOptions(OptionsResolver $resolver)
+        public function configureOptions(OptionsResolver $resolver): void
         {
             $resolver->setDefaults([
                 'empty_data' => new Blog($this->someDependency),
@@ -96,7 +96,7 @@ The closure must accept a ``FormInterface`` instance as the first argument::
     use Symfony\Component\OptionsResolver\OptionsResolver;
     // ...
 
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             'empty_data' => function (FormInterface $form) {
diff --git a/form/validation_group_service_resolver.rst b/form/validation_group_service_resolver.rst
index e497a7556df..ad741fbdb3a 100644
--- a/form/validation_group_service_resolver.rst
+++ b/form/validation_group_service_resolver.rst
@@ -23,11 +23,7 @@ parameter::
             $this->service2 = $service2;
         }
 
-        /**
-         * @param FormInterface $form
-         * @return array
-         */
-        public function __invoke(FormInterface $form)
+        public function __invoke(FormInterface $form): array
         {
             $groups = [];
 
@@ -56,7 +52,7 @@ Then in your form, inject the resolver and set it as the ``validation_groups``::
         }
 
         // ...
-        public function configureOptions(OptionsResolver $resolver)
+        public function configureOptions(OptionsResolver $resolver): void
         {
             $resolver->setDefaults([
                 'validation_groups' => $this->groupResolver,
diff --git a/form/validation_groups.rst b/form/validation_groups.rst
index 2dfe2889de9..a215ed02aba 100644
--- a/form/validation_groups.rst
+++ b/form/validation_groups.rst
@@ -20,7 +20,7 @@ following to the ``configureOptions()`` method::
 
     use Symfony\Component\OptionsResolver\OptionsResolver;
 
-    public function configureOptions(OptionsResolver $resolver)
+    public function configureOptions(OptionsResolver $resolver): void
     {
         $resolver->setDefaults([
             // ...
diff --git a/form/without_class.rst b/form/without_class.rst
index 50efc1dbcc7..85838d77ce9 100644
--- a/form/without_class.rst
+++ b/form/without_class.rst
@@ -12,28 +12,35 @@ But sometimes, you may want to use a form without a class, and get back an
 array of the submitted data. The ``getData()`` method allows you to do
 exactly that::
 
-    // make sure you've imported the Request namespace above the class
+    // src/Controller/ContactController.php
+    namespace App\Controller;
+
+    use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
     use Symfony\Component\HttpFoundation\Request;
+    use Symfony\Component\HttpFoundation\Response;
     // ...
 
-    public function contact(Request $request)
+    class ContactController extends AbstractController
     {
-        $defaultData = ['message' => 'Type your message here'];
-        $form = $this->createFormBuilder($defaultData)
-            ->add('name', TextType::class)
-            ->add('email', EmailType::class)
-            ->add('message', TextareaType::class)
-            ->add('send', SubmitType::class)
-            ->getForm();
-
-        $form->handleRequest($request);
-
-        if ($form->isSubmitted() && $form->isValid()) {
-            // data is an array with "name", "email", and "message" keys
-            $data = $form->getData();
+        public function contact(Request $request): Response
+        {
+            $defaultData = ['message' => 'Type your message here'];
+            $form = $this->createFormBuilder($defaultData)
+                ->add('name', TextType::class)
+                ->add('email', EmailType::class)
+                ->add('message', TextareaType::class)
+                ->add('send', SubmitType::class)
+                ->getForm();
+
+            $form->handleRequest($request);
+
+            if ($form->isSubmitted() && $form->isValid()) {
+                // data is an array with "name", "email", and "message" keys
+                $data = $form->getData();
+            }
+
+            // ... render the form
         }
-
-        // ... render the form
     }
 
 By default, a form actually assumes that you want to work with arrays of
@@ -85,7 +92,7 @@ but here's a short example::
     use Symfony\Component\Validator\Constraints\Length;
     use Symfony\Component\Validator\Constraints\NotBlank;
 
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    public function buildForm(FormBuilderInterface $builder, array $options): void
     {
         $builder
             ->add('firstName', TextType::class, [
diff --git a/forms.rst b/forms.rst
index 6923660a016..12013e8fbfc 100644
--- a/forms.rst
+++ b/forms.rst
@@ -49,22 +49,22 @@ following ``Task`` class::
         protected $task;
         protected $dueDate;
 
-        public function getTask()
+        public function getTask(): string
         {
             return $this->task;
         }
 
-        public function setTask($task)
+        public function setTask(string $task): void
         {
             $this->task = $task;
         }
 
-        public function getDueDate()
+        public function getDueDate(): ?\DateTime
         {
             return $this->dueDate;
         }
 
-        public function setDueDate(\DateTime $dueDate = null)
+        public function setDueDate(?\DateTime $dueDate): void
         {
             $this->dueDate = $dueDate;
         }
@@ -122,10 +122,11 @@ use the ``createFormBuilder()`` helper::
     use Symfony\Component\Form\Extension\Core\Type\SubmitType;
     use Symfony\Component\Form\Extension\Core\Type\TextType;
     use Symfony\Component\HttpFoundation\Request;
+    use Symfony\Component\HttpFoundation\Response;
 
     class TaskController extends AbstractController
     {
-        public function new(Request $request)
+        public function new(Request $request): Response
         {
             // creates a task object and initializes some data for this example
             $task = new Task();
@@ -178,7 +179,7 @@ implements the interface and provides some utilities::
 
     class TaskType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 ->add('task', TextType::class)
@@ -206,7 +207,7 @@ use the ``createForm()`` helper (otherwise, use the ``create()`` method of the
 
     class TaskController extends AbstractController
     {
-        public function new()
+        public function new(): Response
         {
             // creates a task object and initializes some data for this example
             $task = new Task();
@@ -241,7 +242,7 @@ the ``data_class`` option by adding the following to your form type class::
     {
         // ...
 
-        public function configureOptions(OptionsResolver $resolver)
+        public function configureOptions(OptionsResolver $resolver): void
         {
             $resolver->setDefaults([
                 'data_class' => Task::class,
@@ -265,10 +266,11 @@ to build another object with the visual representation of the form::
     use App\Form\Type\TaskType;
     use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
     use Symfony\Component\HttpFoundation\Request;
+    use Symfony\Component\HttpFoundation\Response;
 
     class TaskController extends AbstractController
     {
-        public function new(Request $request)
+        public function new(Request $request): Response
         {
             $task = new Task();
             // ...
@@ -374,34 +376,39 @@ Processing a form means to translate user-submitted data back to the properties
 of an object. To make this happen, the submitted data from the user must be
 written into the form object::
 
+    // src/Controller/TaskController.php
+
     // ...
     use Symfony\Component\HttpFoundation\Request;
 
-    public function new(Request $request)
+    class TaskController extends AbstractController
     {
-        // just setup a fresh $task object (remove the example data)
-        $task = new Task();
+        public function new(Request $request): Response
+        {
+            // just setup a fresh $task object (remove the example data)
+            $task = new Task();
 
-        $form = $this->createForm(TaskType::class, $task);
+            $form = $this->createForm(TaskType::class, $task);
 
-        $form->handleRequest($request);
-        if ($form->isSubmitted() && $form->isValid()) {
-            // $form->getData() holds the submitted values
-            // but, the original `$task` variable has also been updated
-            $task = $form->getData();
+            $form->handleRequest($request);
+            if ($form->isSubmitted() && $form->isValid()) {
+                // $form->getData() holds the submitted values
+                // but, the original `$task` variable has also been updated
+                $task = $form->getData();
 
-            // ... perform some action, such as saving the task to the database
-            // for example, if Task is a Doctrine entity, save it!
-            // $entityManager = $this->getDoctrine()->getManager();
-            // $entityManager->persist($task);
-            // $entityManager->flush();
+                // ... perform some action, such as saving the task to the database
+                // for example, if Task is a Doctrine entity, save it!
+                // $entityManager = $this->getDoctrine()->getManager();
+                // $entityManager->persist($task);
+                // $entityManager->flush();
 
-            return $this->redirectToRoute('task_success');
-        }
+                return $this->redirectToRoute('task_success');
+            }
 
-        return $this->render('task/new.html.twig', [
-            'form' => $form->createView(),
-        ]);
+            return $this->render('task/new.html.twig', [
+                'form' => $form->createView(),
+            ]);
+        }
     }
 
 This controller follows a common pattern for handling forms and has three
@@ -534,7 +541,7 @@ object.
         {
             // ...
 
-            public static function loadValidatorMetadata(ClassMetadata $metadata)
+            public static function loadValidatorMetadata(ClassMetadata $metadata): void
             {
                 $metadata->addPropertyConstraint('task', new NotBlank());
 
@@ -571,7 +578,7 @@ argument of ``createForm()``::
 
     class TaskController extends AbstractController
     {
-        public function new()
+        public function new(): Response
         {
             $task = new Task();
             // use some PHP logic to decide if this form field is required or not
@@ -599,7 +606,7 @@ options they accept using the ``configureOptions()`` method::
     {
         // ...
 
-        public function configureOptions(OptionsResolver $resolver)
+        public function configureOptions(OptionsResolver $resolver): void
         {
             $resolver->setDefaults([
                 // ...,
@@ -623,7 +630,7 @@ Now you can use this new form option inside the ``buildForm()`` method::
 
     class TaskType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 // ...
@@ -699,6 +706,7 @@ use the ``setAction()`` and ``setMethod()`` methods to change this::
     // src/Controller/TaskController.php
     namespace App\Controller;
 
+    // ...
     use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
     use Symfony\Component\Form\Extension\Core\Type\DateType;
     use Symfony\Component\Form\Extension\Core\Type\SubmitType;
@@ -706,7 +714,7 @@ use the ``setAction()`` and ``setMethod()`` methods to change this::
 
     class TaskController extends AbstractController
     {
-        public function new()
+        public function new(): Response
         {
             // ...
 
@@ -727,10 +735,11 @@ When building the form in a class, pass the action and method as form options::
 
     use App\Form\TaskType;
     use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+    // ...
 
     class TaskController extends AbstractController
     {
-        public function new()
+        public function new(): Response
         {
             // ...
 
@@ -775,10 +784,11 @@ method::
 
     use App\Form\TaskType;
     use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+    // ...
 
     class TaskController extends AbstractController
     {
-        public function new()
+        public function new(): Response
         {
             $task = ...;
             $form = $this->get('form.factory')->createNamed('my_name', TaskType::class, $task);
@@ -839,7 +849,7 @@ pass ``null`` to it, to enable Symfony's "guessing mechanism"::
 
     class TaskType extends AbstractType
     {
-        public function buildForm(FormBuilderInterface $builder, array $options)
+        public function buildForm(FormBuilderInterface $builder, array $options): void
         {
             $builder
                 // if you don't define field options, you can omit the second argument
@@ -897,16 +907,20 @@ If you need extra fields in the form that won't be stored in the object (for
 example to add an *"I agree with these terms"* checkbox), set the ``mapped``
 option to ``false`` in those fields::
 
+    // ...
     use Symfony\Component\Form\FormBuilderInterface;
 
-    public function buildForm(FormBuilderInterface $builder, array $options)
+    class TaskType extends AbstractType
     {
-        $builder
-            ->add('task')
-            ->add('dueDate')
-            ->add('agreeTerms', CheckboxType::class, ['mapped' => false])
-            ->add('save', SubmitType::class)
-        ;
+        public function buildForm(FormBuilderInterface $builder, array $options): void
+        {
+            $builder
+                ->add('task')
+                ->add('dueDate')
+                ->add('agreeTerms', CheckboxType::class, ['mapped' => false])
+                ->add('save', SubmitType::class)
+            ;
+        }
     }
 
 These "unmapped fields" can be set and accessed in a controller with::

From 8f8621d99c344a3937f505ca12fade3a6e95f04a Mon Sep 17 00:00:00 2001
From: Wouter de Jong <wouter@wouterj.nl>
Date: Sun, 8 Nov 2020 15:05:59 +0100
Subject: [PATCH 3/3] Added PHP types to the DI related articles

---
 service_container.rst                         |  4 ++--
 service_container/autowiring.rst              | 19 +++++++++++--------
 service_container/calls.rst                   |  4 ++--
 service_container/compiler_passes.rst         |  4 ++--
 service_container/configurators.rst           |  8 ++++----
 service_container/factories.rst               |  4 ++--
 service_container/injection_types.rst         |  6 +++---
 service_container/optional_dependencies.rst   |  2 +-
 service_container/parent_services.rst         |  2 +-
 .../service_subscribers_locators.rst          | 12 ++++++------
 service_container/synthetic_services.rst      |  2 +-
 service_container/tags.rst                    | 18 ++++++++++--------
 12 files changed, 45 insertions(+), 40 deletions(-)

diff --git a/service_container.rst b/service_container.rst
index ff80ac27a14..09e26cd4d0b 100644
--- a/service_container.rst
+++ b/service_container.rst
@@ -340,7 +340,7 @@ you can type-hint the new ``SiteUpdateManager`` class and use it::
 
     // src/Controller/SiteController.php
     namespace App\Controller;
-    
+
     // ...
     use App\Service\SiteUpdateManager;
 
@@ -378,7 +378,7 @@ example, suppose you want to make the admin email configurable:
     +    private $adminEmail;
 
     -    public function __construct(MessageGenerator $messageGenerator, MailerInterface $mailer)
-    +    public function __construct(MessageGenerator $messageGenerator, MailerInterface $mailer, $adminEmail)
+    +    public function __construct(MessageGenerator $messageGenerator, MailerInterface $mailer, string $adminEmail)
         {
             // ...
     +        $this->adminEmail = $adminEmail;
diff --git a/service_container/autowiring.rst b/service_container/autowiring.rst
index 167fb4562f4..04058c6b9ac 100644
--- a/service_container/autowiring.rst
+++ b/service_container/autowiring.rst
@@ -29,7 +29,7 @@ Start by creating a ROT13 transformer class::
 
     class Rot13Transformer
     {
-        public function transform($value)
+        public function transform(string $value): string
         {
             return str_rot13($value);
         }
@@ -41,6 +41,7 @@ And now a Twitter client using this transformer::
     namespace App\Service;
 
     use App\Util\Rot13Transformer;
+    // ...
 
     class TwitterClient
     {
@@ -51,7 +52,7 @@ And now a Twitter client using this transformer::
             $this->transformer = $transformer;
         }
 
-        public function tweet($user, $key, $status)
+        public function tweet(User $user, string $key, string $status): void
         {
             $transformedStatus = $this->transformer->transform($status);
 
@@ -129,6 +130,8 @@ Now, you can use the ``TwitterClient`` service immediately in a controller::
 
     use App\Service\TwitterClient;
     use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+    use Symfony\Component\HttpFoundation\Request;
+    use Symfony\Component\HttpFoundation\Response;
     use Symfony\Component\Routing\Annotation\Route;
 
     class DefaultController extends AbstractController
@@ -136,7 +139,7 @@ Now, you can use the ``TwitterClient`` service immediately in a controller::
         /**
          * @Route("/tweet", methods={"POST"})
          */
-        public function tweet(TwitterClient $twitterClient)
+        public function tweet(TwitterClient $twitterClient, Request $request): Response
         {
             // fetch $user, $key, $status from the POST'ed data
 
@@ -288,7 +291,7 @@ To follow this best practice, suppose you decide to create a ``TransformerInterf
 
     interface TransformerInterface
     {
-        public function transform($value);
+        public function transform(string $value): string;
     }
 
 Then, you update ``Rot13Transformer`` to implement it::
@@ -388,7 +391,7 @@ Suppose you create a second class - ``UppercaseTransformer`` that implements
 
     class UppercaseTransformer implements TransformerInterface
     {
-        public function transform($value)
+        public function transform(string $value): string
         {
             return strtoupper($value);
         }
@@ -426,7 +429,7 @@ the injection::
             $this->transformer = $shoutyTransformer;
         }
 
-        public function toot($user, $key, $status)
+        public function toot(User $user, string $key, string $status): void
         {
             $transformedStatus = $this->transformer->transform($status);
 
@@ -565,12 +568,12 @@ to inject the ``logger`` service, and decide to use setter-injection::
         /**
          * @required
          */
-        public function setLogger(LoggerInterface $logger)
+        public function setLogger(LoggerInterface $logger): void
         {
             $this->logger = $logger;
         }
 
-        public function transform($value)
+        public function transform(string $value): string
         {
             $this->logger->info('Transforming '.$value);
             // ...
diff --git a/service_container/calls.rst b/service_container/calls.rst
index 00069a2ccb2..78418aadf13 100644
--- a/service_container/calls.rst
+++ b/service_container/calls.rst
@@ -22,7 +22,7 @@ example::
     {
         private $logger;
 
-        public function setLogger(LoggerInterface $logger)
+        public function setLogger(LoggerInterface $logger): void
         {
             $this->logger = $logger;
         }
@@ -97,7 +97,7 @@ instead of mutating the object they were called on::
         /**
          * @return static
          */
-        public function withLogger(LoggerInterface $logger)
+        public function withLogger(LoggerInterface $logger): self
         {
             $new = clone $this;
             $new->logger = $logger;
diff --git a/service_container/compiler_passes.rst b/service_container/compiler_passes.rst
index 4d959e93dc6..79f666a4237 100644
--- a/service_container/compiler_passes.rst
+++ b/service_container/compiler_passes.rst
@@ -52,7 +52,7 @@ and process the services inside the ``process()`` method::
 
         // ...
 
-        public function process(ContainerBuilder $container)
+        public function process(ContainerBuilder $container): void
         {
             // in this method you can manipulate the service container:
             // for example, changing some container service:
@@ -81,7 +81,7 @@ method in the extension)::
 
     class MyBundle extends Bundle
     {
-        public function build(ContainerBuilder $container)
+        public function build(ContainerBuilder $container): void
         {
             parent::build($container);
 
diff --git a/service_container/configurators.rst b/service_container/configurators.rst
index 92c1afc5794..5331d0ba7ac 100644
--- a/service_container/configurators.rst
+++ b/service_container/configurators.rst
@@ -28,7 +28,7 @@ You start defining a ``NewsletterManager`` class like this::
     {
         private $enabledFormatters;
 
-        public function setEnabledFormatters(array $enabledFormatters)
+        public function setEnabledFormatters(array $enabledFormatters): void
         {
             $this->enabledFormatters = $enabledFormatters;
         }
@@ -45,7 +45,7 @@ and also a ``GreetingCardManager`` class::
     {
         private $enabledFormatters;
 
-        public function setEnabledFormatters(array $enabledFormatters)
+        public function setEnabledFormatters(array $enabledFormatters): void
         {
             $this->enabledFormatters = $enabledFormatters;
         }
@@ -65,7 +65,7 @@ in the application::
     {
         // ...
 
-        public function getEnabledFormatters()
+        public function getEnabledFormatters(): array
         {
             // code to configure which formatters to use
             $enabledFormatters = [...];
@@ -92,7 +92,7 @@ to create a configurator class to configure these instances::
             $this->formatterManager = $formatterManager;
         }
 
-        public function configure(EmailFormatterAwareInterface $emailManager)
+        public function configure(EmailFormatterAwareInterface $emailManager): void
         {
             $emailManager->setEnabledFormatters(
                 $this->formatterManager->getEnabledFormatters()
diff --git a/service_container/factories.rst b/service_container/factories.rst
index f6ccd5a1198..9f01e7dc7a6 100644
--- a/service_container/factories.rst
+++ b/service_container/factories.rst
@@ -26,7 +26,7 @@ object by calling the static ``createNewsletterManager()`` method::
 
     class NewsletterManagerStaticFactory
     {
-        public static function createNewsletterManager()
+        public static function createNewsletterManager(): NewsletterManager
         {
             $newsletterManager = new NewsletterManager();
 
@@ -180,7 +180,7 @@ factory service can be used as a callback::
     // ...
     class InvokableNewsletterManagerFactory
     {
-        public function __invoke()
+        public function __invoke(): NewsletterManager
         {
             $newsletterManager = new NewsletterManager();
 
diff --git a/service_container/injection_types.rst b/service_container/injection_types.rst
index 097540bd8f6..6b7b74d1d24 100644
--- a/service_container/injection_types.rst
+++ b/service_container/injection_types.rst
@@ -130,7 +130,7 @@ by cloning the original service, this approach allows you to make a service immu
          * @required
          * @return static
          */
-        public function withMailer(MailerInterface $mailer)
+        public function withMailer(MailerInterface $mailer): self
         {
             $new = clone $this;
             $new->mailer = $mailer;
@@ -224,7 +224,7 @@ that accepts the dependency::
 
     // src/Mail/NewsletterManager.php
     namespace App\Mail;
-    
+
     // ...
     class NewsletterManager
     {
@@ -233,7 +233,7 @@ that accepts the dependency::
         /**
          * @required
          */
-        public function setMailer(MailerInterface $mailer)
+        public function setMailer(MailerInterface $mailer): void
         {
             $this->mailer = $mailer;
         }
diff --git a/service_container/optional_dependencies.rst b/service_container/optional_dependencies.rst
index ca702176341..b981877a942 100644
--- a/service_container/optional_dependencies.rst
+++ b/service_container/optional_dependencies.rst
@@ -113,7 +113,7 @@ In YAML, the special ``@?`` syntax tells the service container that the
 dependency is optional. The ``NewsletterManager`` must also be rewritten by
 adding a ``setLogger()`` method::
 
-        public function setLogger(LoggerInterface $logger)
+        public function setLogger(LoggerInterface $logger): void
         {
             // ...
         }
diff --git a/service_container/parent_services.rst b/service_container/parent_services.rst
index 561721a2a8a..de0d5658b15 100644
--- a/service_container/parent_services.rst
+++ b/service_container/parent_services.rst
@@ -26,7 +26,7 @@ you may have multiple repository classes which need the
             $this->objectManager = $objectManager;
         }
 
-        public function setLogger(LoggerInterface $logger)
+        public function setLogger(LoggerInterface $logger): void
         {
             $this->logger = $logger;
         }
diff --git a/service_container/service_subscribers_locators.rst b/service_container/service_subscribers_locators.rst
index a9579bcfcc3..2fc0ec54fb1 100644
--- a/service_container/service_subscribers_locators.rst
+++ b/service_container/service_subscribers_locators.rst
@@ -87,7 +87,7 @@ a PSR-11 ``ContainerInterface``::
             $this->locator = $locator;
         }
 
-        public static function getSubscribedServices()
+        public static function getSubscribedServices(): array
         {
             return [
                 'App\FooCommand' => FooHandler::class,
@@ -130,7 +130,7 @@ service locator::
 
     use Psr\Log\LoggerInterface;
 
-    public static function getSubscribedServices()
+    public static function getSubscribedServices(): array
     {
         return [
             // ...
@@ -142,7 +142,7 @@ Service types can also be keyed by a service name for internal use::
 
     use Psr\Log\LoggerInterface;
 
-    public static function getSubscribedServices()
+    public static function getSubscribedServices(): array
     {
         return [
             // ...
@@ -159,7 +159,7 @@ typically happens when extending ``AbstractController``::
 
     class MyController extends AbstractController
     {
-        public static function getSubscribedServices()
+        public static function getSubscribedServices(): array
         {
             return array_merge(parent::getSubscribedServices(), [
                 // ...
@@ -176,7 +176,7 @@ errors if there's no matching service found in the service container::
 
     use Psr\Log\LoggerInterface;
 
-    public static function getSubscribedServices()
+    public static function getSubscribedServices(): array
     {
         return [
             // ...
@@ -395,7 +395,7 @@ will share identical locators among all the services referencing them::
     use Symfony\Component\DependencyInjection\ContainerBuilder;
     use Symfony\Component\DependencyInjection\Reference;
 
-    public function process(ContainerBuilder $container)
+    public function process(ContainerBuilder $container): void
     {
         // ...
 
diff --git a/service_container/synthetic_services.rst b/service_container/synthetic_services.rst
index 5a3ea59d276..59869d5d7f3 100644
--- a/service_container/synthetic_services.rst
+++ b/service_container/synthetic_services.rst
@@ -18,7 +18,7 @@ from within the ``Kernel`` class::
     {
         // ...
 
-        protected function initializeContainer()
+        protected function initializeContainer(): void
         {
             // ...
             $this->container->set('kernel', $this);
diff --git a/service_container/tags.rst b/service_container/tags.rst
index bbe7df1af6b..8bddd65c795 100644
--- a/service_container/tags.rst
+++ b/service_container/tags.rst
@@ -126,7 +126,7 @@ In a Symfony application, call this method in your kernel class::
     {
         // ...
 
-        protected function build(ContainerBuilder $container)
+        protected function build(ContainerBuilder $container): void
         {
             $container->registerForAutoconfiguration(CustomInterface::class)
                 ->addTag('app.custom_tag')
@@ -142,7 +142,7 @@ In a Symfony bundle, call this method in the ``load()`` method of the
     {
         // ...
 
-        public function load(array $configs, ContainerBuilder $container)
+        public function load(array $configs, ContainerBuilder $container): void
         {
             $container->registerForAutoconfiguration(CustomInterface::class)
                 ->addTag('app.custom_tag')
@@ -178,7 +178,7 @@ To begin with, define the ``TransportChain`` class::
             $this->transports = [];
         }
 
-        public function addTransport(\Swift_Transport $transport)
+        public function addTransport(\Swift_Transport $transport): void
         {
             $this->transports[] = $transport;
         }
@@ -304,7 +304,7 @@ container for any services with the ``app.mail_transport`` tag::
 
     class MailTransportPass implements CompilerPassInterface
     {
-        public function process(ContainerBuilder $container)
+        public function process(ContainerBuilder $container): void
         {
             // always first check if the primary service is defined
             if (!$container->has(TransportChain::class)) {
@@ -341,7 +341,7 @@ or from your kernel::
     {
         // ...
 
-        protected function build(ContainerBuilder $container)
+        protected function build(ContainerBuilder $container): void
         {
             $container->addCompilerPass(new MailTransportPass());
         }
@@ -372,16 +372,18 @@ To begin with, change the ``TransportChain`` class::
             $this->transports = [];
         }
 
-        public function addTransport(\Swift_Transport $transport, $alias)
+        public function addTransport(\Swift_Transport $transport, $alias): void
         {
             $this->transports[$alias] = $transport;
         }
 
-        public function getTransport($alias)
+        public function getTransport($alias): ?\Swift_Transport
         {
             if (array_key_exists($alias, $this->transports)) {
                 return $this->transports[$alias];
             }
+
+            return null;
         }
     }
 
@@ -476,7 +478,7 @@ use this, update the compiler::
 
     class TransportCompilerPass implements CompilerPassInterface
     {
-        public function process(ContainerBuilder $container)
+        public function process(ContainerBuilder $container): void
         {
             // ...