1.  class ContainerBuilder extends SymfonyContainerBuilder {
2.  
3. +  protected $explicitlySet = [];
4. +
5.    /**
6.     * {@inheritdoc}
7.     */
8. @@ -44,6 +48,7 @@ public function set($id, $service, $scope = self::SCOPE_CONTAINER) {
9.      if (strtolower($id) !== $id) {
10.        throw new \InvalidArgumentException("Service ID names must be lowercase: $id");
11.      }
12. +    $this->explicitlySet[$id] = TRUE;
13.      SymfonyContainer::set($id, $service, $scope);
14.  
15.      // Ensure that the _serviceId property is set on synthetic services as well.
16. @@ -100,6 +105,17 @@ private function synchronize($id) {
17.    }
18.  
19.    /**
20. +   * {@inheritdoc}
21. +   */
22. +  public function compile() {
23. +    parent::compile();
24. +    // Remove all non-synthetic services set by compiler passes. For example,
25. +    // cache bins are forced to NulLBackend before the ListCacheBinsPass and
26. +    // so cache services might got stored as NullBackend.
27. +    $this->services = array_intersect_key($this->services, $this->explicitlySet);
28. +  }
29. +
30. +  /**
31.     * A 1to1 copy of parent::callMethod.
32.     */
33.    protected function callMethod($service, $call) {
34.