diff --git a/src/Symfony/Component/DependencyInjection/Loader/Configurator/AbstractConfigurator.php b/src/Symfony/Component/DependencyInjection/Loader/Configurator/AbstractConfigurator.php
index 2c4538e201..73ca320e31 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/Configurator/AbstractConfigurator.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/Configurator/AbstractConfigurator.php
@@ -22,6 +22,9 @@ abstract class AbstractConfigurator
 {
     const FACTORY = 'unknown';
 
+    /** @internal */
+    protected $definition;
+
     public function __call($method, $args)
     {
         if (method_exists($this, 'set'.$method)) {
@@ -37,7 +40,7 @@ abstract class AbstractConfigurator
      * @param mixed $value
      * @param bool  $allowServices whether Definition and Reference are allowed; by default, only scalars and arrays are
      *
-     * @return mixed the value, optionaly cast to a Definition/Reference
+     * @return mixed the value, optionally cast to a Definition/Reference
      */
     public static function processValue($value, $allowServices = false)
     {
@@ -50,32 +53,14 @@ abstract class AbstractConfigurator
         }
 
         if ($value instanceof ReferenceConfigurator) {
-            static $refCast;
-
-            if (!$refCast) {
-                $refCast = \Closure::bind(function ($value) {
-                    return new Reference($value->id, $value->invalidBehavior);
-                }, null, $value);
-            }
-
-            // cast ReferenceConfigurator to Reference
-            return $refCast($value);
+            return new Reference($value->id, $value->invalidBehavior);
         }
 
         if ($value instanceof InlineServiceConfigurator) {
-            static $defCast;
+            $def = $value->definition;
+            $value->definition = null;
 
-            if (!$defCast) {
-                $defCast = \Closure::bind(function ($value) {
-                    $def = $value->definition;
-                    $value->definition = null;
-
-                    return $def;
-                }, null, $value);
-            }
-
-            // cast InlineServiceConfigurator to Definition
-            return $defCast($value);
+            return $def;
         }
 
         if ($value instanceof self) {
diff --git a/src/Symfony/Component/DependencyInjection/Loader/Configurator/AbstractServiceConfigurator.php b/src/Symfony/Component/DependencyInjection/Loader/Configurator/AbstractServiceConfigurator.php
index 72ca7320b9..40b6c2f389 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/Configurator/AbstractServiceConfigurator.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/Configurator/AbstractServiceConfigurator.php
@@ -17,9 +17,8 @@ use Symfony\Component\DependencyInjection\Exception\ServiceNotFoundException;
 abstract class AbstractServiceConfigurator extends AbstractConfigurator
 {
     protected $parent;
-    protected $definition;
     protected $id;
-    protected $defaultTags = array();
+    private $defaultTags = array();
 
     public function __construct(ServicesConfigurator $parent, Definition $definition, $id = null, array $defaultTags = array())
     {
@@ -59,7 +58,7 @@ abstract class AbstractServiceConfigurator extends AbstractConfigurator
      * Creates an alias.
      *
      * @param string $id
-     * @param string $ref
+     * @param string $referencedId
      *
      * @return AliasConfigurator
      */
diff --git a/src/Symfony/Component/DependencyInjection/Loader/Configurator/ReferenceConfigurator.php b/src/Symfony/Component/DependencyInjection/Loader/Configurator/ReferenceConfigurator.php
index 93fdf3960e..1585c0872a 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/Configurator/ReferenceConfigurator.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/Configurator/ReferenceConfigurator.php
@@ -16,10 +16,13 @@ use Symfony\Component\DependencyInjection\ContainerInterface;
 /**
  * @author Nicolas Grekas <p@tchwork.com>
  */
-class ReferenceConfigurator
+class ReferenceConfigurator extends AbstractConfigurator
 {
-    private $id;
-    private $invalidBehavior = ContainerInterface::EXCEPTION_ON_INVALID_REFERENCE;
+    /** @internal */
+    protected $id;
+
+    /** @internal */
+    protected $invalidBehavior = ContainerInterface::EXCEPTION_ON_INVALID_REFERENCE;
 
     public function __construct($id)
     {
diff --git a/src/Symfony/Component/DependencyInjection/Loader/Configurator/Traits/AbstractTrait.php b/src/Symfony/Component/DependencyInjection/Loader/Configurator/Traits/AbstractTrait.php
index 47e0dee287..f69a7a5be1 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/Configurator/Traits/AbstractTrait.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/Configurator/Traits/AbstractTrait.php
@@ -11,8 +11,6 @@
 
 namespace Symfony\Component\DependencyInjection\Loader\Configurator\Traits;
 
-use Symfony\Component\DependencyInjection\Definition;
-
 /**
  * @method $this abstract(bool $abstract = true)
  */
diff --git a/src/Symfony/Component/DependencyInjection/Loader/Configurator/Traits/AutoconfigureTrait.php b/src/Symfony/Component/DependencyInjection/Loader/Configurator/Traits/AutoconfigureTrait.php
index e3dccc9656..42a692353e 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/Configurator/Traits/AutoconfigureTrait.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/Configurator/Traits/AutoconfigureTrait.php
@@ -11,6 +11,7 @@
 
 namespace Symfony\Component\DependencyInjection\Loader\Configurator\Traits;
 
+use Symfony\Component\DependencyInjection\ChildDefinition;
 use Symfony\Component\DependencyInjection\Exception\InvalidArgumentException;
 
 trait AutoconfigureTrait
diff --git a/src/Symfony/Component/DependencyInjection/Loader/Configurator/Traits/DeprecateTrait.php b/src/Symfony/Component/DependencyInjection/Loader/Configurator/Traits/DeprecateTrait.php
index 331be473e2..b14a6557ee 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/Configurator/Traits/DeprecateTrait.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/Configurator/Traits/DeprecateTrait.php
@@ -11,7 +11,6 @@
 
 namespace Symfony\Component\DependencyInjection\Loader\Configurator\Traits;
 
-use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\DependencyInjection\Exception\InvalidArgumentException;
 
 trait DeprecateTrait
diff --git a/src/Symfony/Component/DependencyInjection/Loader/Configurator/Traits/TagTrait.php b/src/Symfony/Component/DependencyInjection/Loader/Configurator/Traits/TagTrait.php
index 4094acdbfc..aeb8b047d4 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/Configurator/Traits/TagTrait.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/Configurator/Traits/TagTrait.php
@@ -11,7 +11,6 @@
 
 namespace Symfony\Component\DependencyInjection\Loader\Configurator\Traits;
 
-use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\DependencyInjection\Exception\InvalidArgumentException;
 
 trait TagTrait
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Fixtures/config/services_autoconfigure_with_parent.php b/src/Symfony/Component/DependencyInjection/Tests/Fixtures/config/services_autoconfigure_with_parent.php
new file mode 100644
index 0000000000..f8ffb1dee9
--- /dev/null
+++ b/src/Symfony/Component/DependencyInjection/Tests/Fixtures/config/services_autoconfigure_with_parent.php
@@ -0,0 +1,9 @@
+<?php
+
+namespace Symfony\Component\DependencyInjection\Loader\Configurator;
+
+return function (ContainerConfigurator $c) {
+    $c->services()
+        ->set('parent_service', \stdClass::class)
+        ->set('child_service')->parent('parent_service')->autoconfigure(true);
+};
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Loader/PhpFileLoaderTest.php b/src/Symfony/Component/DependencyInjection/Tests/Loader/PhpFileLoaderTest.php
index 02f84311e6..a8f10d9ef0 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Loader/PhpFileLoaderTest.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Loader/PhpFileLoaderTest.php
@@ -76,4 +76,17 @@ class PhpFileLoaderTest extends TestCase
             yield array('php7');
         }
     }
+
+    /**
+     * @expectedException \Symfony\Component\DependencyInjection\Exception\InvalidArgumentException
+     * @expectedExceptionMessage The service "child_service" cannot have a "parent" and also have "autoconfigure". Try disabling autoconfiguration for the service.
+     */
+    public function testAutoConfigureAndChildDefinitionNotAllowed()
+    {
+        $fixtures = realpath(__DIR__.'/../Fixtures');
+        $container = new ContainerBuilder();
+        $loader = new PhpFileLoader($container, new FileLocator());
+        $loader->load($fixtures.'/config/services_autoconfigure_with_parent.php');
+        $container->compile();
+    }
 }