diff --git a/src/Symfony/Component/DependencyInjection/Loader/FileLoader.php b/src/Symfony/Component/DependencyInjection/Loader/FileLoader.php
index bb9dc214e6a50..def72ad142530 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/FileLoader.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/FileLoader.php
@@ -59,11 +59,48 @@ public function registerClasses(Definition $prototype, $namespace, $resource)
         }
 
         $classes = $this->findClasses($namespace, $resource);
+
+        $unusedArguments = array();
+        foreach ($prototype->getArguments() as $key => $argument) {
+            if ('' === $key || '$' !== $key[0]) {
+                continue;
+            }
+
+            $unusedArguments[$key] = true;
+        }
+
         // prepare for deep cloning
         $prototype = serialize($prototype);
 
-        foreach ($classes as $class) {
-            $this->setDefinition($class, unserialize($prototype));
+        foreach ($classes as $class => $reflectionClass) {
+            $parameters = array();
+            if ($reflectionClass->hasMethod('__construct')) {
+                foreach ($reflectionClass->getMethod('__construct')->getParameters() as $parameter) {
+                    $parameters['$'.$parameter->name] = true;
+                }
+            }
+
+            $definition = unserialize($prototype);
+
+            $arguments = array();
+            foreach ($definition->getArguments() as $key => $argument) {
+                if ('' !== $key && '$' === $key[0]) {
+                    if (!isset($parameters[$key])) {
+                        continue;
+                    }
+
+                    unset($unusedArguments[$key]);
+                }
+
+                $arguments[$key] = $argument;
+            }
+            $definition->setArguments($arguments);
+
+            $this->setDefinition($class, $definition);
+        }
+
+        if ($unusedArguments) {
+            throw new InvalidArgumentException(sprintf('Unused named arguments in a prototype: "%s".', implode('", "', array_keys($unusedArguments))));
         }
     }
 
@@ -104,7 +141,7 @@ private function findClasses($namespace, $resource)
                 continue;
             }
             if (!$r->isInterface() && !$r->isTrait()) {
-                $classes[] = $class;
+                $classes[$class] = $r;
             }
         }
 
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Fixtures/Prototype/Foo.php b/src/Symfony/Component/DependencyInjection/Tests/Fixtures/Prototype/Foo.php
index 1e4f283c8f16e..5520c2fd1dbf4 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Fixtures/Prototype/Foo.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Fixtures/Prototype/Foo.php
@@ -4,4 +4,7 @@
 
 class Foo
 {
+    public function __construct($bar = null)
+    {
+    }
 }
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Fixtures/yaml/prototype_named_args.yml b/src/Symfony/Component/DependencyInjection/Tests/Fixtures/yaml/prototype_named_args.yml
new file mode 100644
index 0000000000000..005085b30b3bc
--- /dev/null
+++ b/src/Symfony/Component/DependencyInjection/Tests/Fixtures/yaml/prototype_named_args.yml
@@ -0,0 +1,5 @@
+services:
+    Symfony\Component\DependencyInjection\Tests\Fixtures\Prototype\:
+        resource: ../Prototype
+        arguments:
+            $bar: foo
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Fixtures/yaml/prototype_unused_named_args.yml b/src/Symfony/Component/DependencyInjection/Tests/Fixtures/yaml/prototype_unused_named_args.yml
new file mode 100644
index 0000000000000..6baa759d72fc1
--- /dev/null
+++ b/src/Symfony/Component/DependencyInjection/Tests/Fixtures/yaml/prototype_unused_named_args.yml
@@ -0,0 +1,6 @@
+services:
+    Symfony\Component\DependencyInjection\Tests\Fixtures\Prototype\:
+        resource: ../Prototype
+        arguments:
+            $invalid: foo
+            $invalid2: quz
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Loader/YamlFileLoaderTest.php b/src/Symfony/Component/DependencyInjection/Tests/Loader/YamlFileLoaderTest.php
index a30aa12c52712..ee04d03a8926b 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Loader/YamlFileLoaderTest.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Loader/YamlFileLoaderTest.php
@@ -24,7 +24,6 @@
 use Symfony\Component\Config\Resource\DirectoryResource;
 use Symfony\Component\Config\Resource\FileResource;
 use Symfony\Component\DependencyInjection\Tests\Fixtures\CaseSensitiveClass;
-use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\DependencyInjection\Tests\Fixtures\Prototype;
 use Symfony\Component\DependencyInjection\Tests\Fixtures\NamedArgumentsDummy;
 use Symfony\Component\ExpressionLanguage\Expression;
@@ -450,6 +449,33 @@ public function testNamedArguments()
         $this->assertEquals(array(array('setApiKey', array('123'))), $container->getDefinition('another_one')->getMethodCalls());
     }
 
+    public function testNamedArgumentsInPrototypes()
+    {
+        $container = new ContainerBuilder();
+        $loader = new YamlFileLoader($container, new FileLocator(self::$fixturesPath.'/yaml'));
+        $loader->load('prototype_named_args.yml');
+
+        $fooDefinition = $container->getDefinition('Symfony\Component\DependencyInjection\Tests\Fixtures\Prototype\Foo');
+        $this->assertEquals(array('$bar' => 'foo'), $fooDefinition->getArguments());
+
+        $this->assertEmpty($container->getDefinition('Symfony\Component\DependencyInjection\Tests\Fixtures\Prototype\Sub\Bar')->getArguments());
+
+        $container->compile();
+
+        $this->assertEquals(array('foo'), $fooDefinition->getArguments());
+    }
+
+    /**
+     * @expectedException \Symfony\Component\DependencyInjection\Exception\InvalidArgumentException
+     * @expectedExceptionMessage Unused named arguments in a prototype: "$invalid", "$invalid2".
+     */
+    public function testUnusedNamedArgumentsInPrototypes()
+    {
+        $container = new ContainerBuilder();
+        $loader = new YamlFileLoader($container, new FileLocator(self::$fixturesPath.'/yaml'));
+        $loader->load('prototype_unused_named_args.yml');
+    }
+
     public function testInstanceof()
     {
         $container = new ContainerBuilder();