diff --git a/core/lib/Drupal/Core/Template/TwigPhpStorageCache.php b/core/lib/Drupal/Core/Template/TwigPhpStorageCache.php
index 258aa36..f83605e 100644
--- a/core/lib/Drupal/Core/Template/TwigPhpStorageCache.php
+++ b/core/lib/Drupal/Core/Template/TwigPhpStorageCache.php
@@ -74,8 +74,18 @@ protected function storage() {
   public function generateKey($name, $className) {
     $hash = hash('sha256', $className);
 
+    if (strpos($name, '{# inline_template_start #}') === 0) {
+      // $name is an inline template, and can have characters that are not valid
+      // for a filename. $hash is unique for each inline template so we just use
+      // the generic name 'inline-template' here.
+      $name = 'inline-template';
+    }
+    else {
+      $name = basename($name);
+    }
+
     // The first part is what is invalidated.
-    return $this->templateCacheFilenamePrefix . '_' . basename($name) . '_' . $hash;
+    return $this->templateCacheFilenamePrefix . '_' . $name . '_' . $hash;
   }
 
   /**
diff --git a/core/modules/system/src/Tests/Theme/TwigEnvironmentTest.php b/core/modules/system/src/Tests/Theme/TwigEnvironmentTest.php
index 1bab9bf..6423c23 100644
--- a/core/modules/system/src/Tests/Theme/TwigEnvironmentTest.php
+++ b/core/modules/system/src/Tests/Theme/TwigEnvironmentTest.php
@@ -65,6 +65,15 @@ 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');
+
+    $cache = $environment->getCache();
+    $class = $environment->getTemplateClass($name);
+    $expected = $hash . '_inline-template' . '_' . hash('sha256', $class);
+    $this->assertEqual($expected, $cache->generateKey($name, $class));
   }
 
   /**