diff --git a/validation/custom_constraint.rst b/validation/custom_constraint.rst
index faee09778b9..d2e7e148266 100644
--- a/validation/custom_constraint.rst
+++ b/validation/custom_constraint.rst
@@ -115,6 +115,8 @@ You can use custom validators like the ones provided by Symfony itself:
     .. code-block:: php-annotations
 
         // src/Entity/AcmeEntity.php
+        namespace App\Entity;
+
         use App\Validator\Constraints as AcmeAssert;
         use Symfony\Component\Validator\Constraints as Assert;
 
@@ -159,6 +161,8 @@ You can use custom validators like the ones provided by Symfony itself:
     .. code-block:: php
 
         // src/Entity/AcmeEntity.php
+        namespace App\Entity;
+
         use App\Validator\Constraints\ContainsAlphanumeric;
         use Symfony\Component\Validator\Constraints\NotBlank;
         use Symfony\Component\Validator\Mapping\ClassMetadata;
@@ -249,6 +253,8 @@ not to the property:
     .. code-block:: php
 
         // src/Entity/AcmeEntity.php
+        namespace App\Entity;
+
         use App\Validator\Constraints\ProtocolClass;
         use Symfony\Component\Validator\Mapping\ClassMetadata;
 
diff --git a/validation/sequence_provider.rst b/validation/sequence_provider.rst
index 98a9389212f..11edc43a7e0 100644
--- a/validation/sequence_provider.rst
+++ b/validation/sequence_provider.rst
@@ -149,6 +149,9 @@ that group are valid, the second group, ``Strict``, will be validated.
 
 You can also define a group sequence in the ``validation_groups`` form option::
 
+    // src/Form/MyType.php
+    namespace App\Form;
+    
     use Symfony\Component\Form\AbstractType;
     use Symfony\Component\OptionsResolver\OptionsResolver;
     use Symfony\Component\Validator\Constraints\GroupSequence;
diff --git a/validation/translations.rst b/validation/translations.rst
index 33d7afdf384..5c22f9362c3 100644
--- a/validation/translations.rst
+++ b/validation/translations.rst
@@ -28,6 +28,8 @@ property is not empty, add the following:
     .. code-block:: php-annotations
 
         // src/Entity/Author.php
+        namespace App\Entity;
+
         use Symfony\Component\Validator\Constraints as Assert;
 
         class Author
@@ -67,6 +69,7 @@ property is not empty, add the following:
     .. code-block:: php
 
         // src/Entity/Author.php
+        namespace App\Entity;
 
         // ...
         use Symfony\Component\Validator\Constraints\NotBlank;