diff --git a/core/lib/Drupal/Core/Template/TwigEnvironment.php b/core/lib/Drupal/Core/Template/TwigEnvironment.php
index cb4df85..0176208 100644
--- a/core/lib/Drupal/Core/Template/TwigEnvironment.php
+++ b/core/lib/Drupal/Core/Template/TwigEnvironment.php
@@ -127,6 +127,11 @@ public function getCacheFilename($name) {
     $class = substr($this->getTemplateClass($name), strlen($this->templateClassPrefix));
 
     // The first part is what is invalidated.
+    if (strpos($name, '{# inline_template_start #}') !== FALSE) {
+      // $name is an inline template, and can have characters that are not valid
+      // for a filename.
+      $name = 'inline-template-' . hash('sha256', $name);
+    }
     return $this->templateCacheFilenamePrefix . '_' . basename($name) . '_' . $class;
   }
 
diff --git a/core/modules/system/src/Tests/Theme/TwigEnvironmentTest.php b/core/modules/system/src/Tests/Theme/TwigEnvironmentTest.php
index 1bab9bf..07eb8ae 100644
--- a/core/modules/system/src/Tests/Theme/TwigEnvironmentTest.php
+++ b/core/modules/system/src/Tests/Theme/TwigEnvironmentTest.php
@@ -65,6 +65,13 @@ public function testInlineTemplate() {
     // Render it twice so that twig caching is triggered.
     $this->assertEqual($renderer->renderRoot($element), 'test-with-context muuh');
     $this->assertEqual($renderer->renderRoot($element_copy), 'test-with-context muuh');
+
+    // Tests caching of inline templates.
+    $name = '{# inline_template_start #}test-with-context {{ llama }}';
+    $hash = $this->container->getParameter('twig_extension_hash');
+    $class = substr($environment->getTemplateClass($name), strlen('__TwigTemplate_'));
+    $expected = $hash . '_inline-template-' . hash('sha256', $name) . '_' . $class;
+    $this->assertEqual($expected, $environment->getCacheFilename($name));
   }
 
   /**