diff --git a/core/lib/Drupal/Component/ProxyBuilder/ProxyDumper.php b/core/lib/Drupal/Component/ProxyBuilder/ProxyDumper.php
index 07e30ee..db3278a 100644
--- a/core/lib/Drupal/Component/ProxyBuilder/ProxyDumper.php
+++ b/core/lib/Drupal/Component/ProxyBuilder/ProxyDumper.php
@@ -37,13 +37,17 @@ public function isProxyCandidate(Definition $definition) {
    * {@inheritdoc}
    */
   public function getProxyFactoryCode(Definition $definition, $id) {
-    $id = var_export($id, TRUE);
     // Note: the specific get method is called initially with $lazyLoad=TRUE;
     // When you want to retrieve the actual service, the code generated in
     // ProxyBuilder calls the method with lazy loading disabled.
-    $output = "        if (\$lazyLoad) {\n";
-    $output .= "            return \$this->services[$id] = new " . $this->builder->buildProxyClassName($definition->getClass()) . '(' . $id . ");\n";
-    $output .= "        }\n";
+    $output = <<<'EOS'
+        if ($lazyLoad) {
+            return $this->services['{{ id }}'] = new {{ class_name }}('{{ id }}');
+        }
+
+EOS;
+    $output = str_replace('{{ id }}', $id, $output);
+    $output = str_replace('{{ class_name }}', $this->builder->buildProxyClassName($definition->getClass()), $output);
 
     return $output;
   }
diff --git a/core/tests/Drupal/Tests/Component/ProxyBuilder/ProxyBuilderTest.php b/core/tests/Drupal/Tests/Component/ProxyBuilder/ProxyBuilderTest.php
index e284902..c8acb00 100644
--- a/core/tests/Drupal/Tests/Component/ProxyBuilder/ProxyBuilderTest.php
+++ b/core/tests/Drupal/Tests/Component/ProxyBuilder/ProxyBuilderTest.php
@@ -161,33 +161,41 @@ public function testMethod($parameter) {
    */
   protected function buildExpectedClass($class, $expected_methods_body, $interface_string = ' ') {
     $proxy_class = $this->proxyBuilder->buildProxyClassName($class);
-    $expected_string = "class $proxy_class $interface_string {
+    $expected_string = <<<'EOS'
+class {{ proxy_class }} {{ interface_string }} {
 
   /**
    * @var string
    */
-  protected \$serviceId;
+  protected $serviceId;
 
   /**
-   * @var \\$class
+   * @var \{{ class }}
    */
-  protected \$service;
+  protected $service;
 
-  public function __construct(\$service_id) {
-    \$this->serviceId = \$service_id;
+  public function __construct($service_id) {
+    $this->serviceId = $service_id;
   }
 
   protected function lazyLoadItself() {
-    if (!isset(\$this->service)) {
-      \$method_name = 'get' . Container::camelize(\$this->serviceId) . 'Service';
-      \$this->service = \\Drupal::getContainer()->\$method_name(FALSE);
+    if (!isset($this->service)) {
+      $method_name = 'get' . Container::camelize($this->serviceId) . 'Service';
+      $this->service = \Drupal::getContainer()->$method_name(FALSE);
     }
 
-    return \$this->service;
+    return $this->service;
   }
-$expected_methods_body
+
+{{ expected_methods_body }}
+
 }
-";
+
+EOS;
+    $expected_string = str_replace('{{ proxy_class }}', $proxy_class, $expected_string);
+    $expected_string = str_replace('{{ class }}', $class, $expected_string);
+    $expected_string = str_replace('{{ expected_methods_body }}', $expected_methods_body, $expected_string);
+    $expected_string = str_replace('{{ interface_string }}', $interface_string, $expected_string);
 
     return $expected_string;
   }