.../src/EventSubscriber/DynamicPageCacheSubscriber.php     |  4 ++--
 .../src/Tests/DynamicPageCacheIntegrationTest.php          |  6 ++++++
 .../dynamic_page_cache_test.routing.yml                    |  7 +++++++
 .../src/DynamicPageCacheTestController.php                 | 14 ++++++++++++--
 4 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/core/modules/dynamic_page_cache/src/EventSubscriber/DynamicPageCacheSubscriber.php b/core/modules/dynamic_page_cache/src/EventSubscriber/DynamicPageCacheSubscriber.php
index 17c2f33..ec0b716 100644
--- a/core/modules/dynamic_page_cache/src/EventSubscriber/DynamicPageCacheSubscriber.php
+++ b/core/modules/dynamic_page_cache/src/EventSubscriber/DynamicPageCacheSubscriber.php
@@ -234,9 +234,9 @@ public function onResponse(FilterResponseEvent $event) {
 
     // If #cache was not set, complain.
     // @see ::onViewRenderArray()
-    // If #cache is not set, complain.
     if ($request->attributes->get(self::ATTRIBUTE_CONTROLLER_RESULT_RENDER_ARRAY_HAS_CACHEABILITY) === FALSE) {
-      throw new \LogicException('The controller returned a render array without cacheability metadata. See https://www.drupal.org/developing/api/8/render/arrays/cacheability.');
+      trigger_error('The controller for the route \'' . $request->attributes->get('_route') . '\' returned a render array without cacheability metadata. See https://www.drupal.org/developing/api/8/render/arrays/cacheability.', E_USER_ERROR);
+      return;
     }
 
     // Embed the response object in a render array so that RenderCache is able
diff --git a/core/modules/dynamic_page_cache/src/Tests/DynamicPageCacheIntegrationTest.php b/core/modules/dynamic_page_cache/src/Tests/DynamicPageCacheIntegrationTest.php
index 5c174a8..31c1636 100644
--- a/core/modules/dynamic_page_cache/src/Tests/DynamicPageCacheIntegrationTest.php
+++ b/core/modules/dynamic_page_cache/src/Tests/DynamicPageCacheIntegrationTest.php
@@ -127,6 +127,12 @@ public function testDynamicPageCache() {
     // Cache.
     $this->drupalGet('dynamic-page-cache-test/html/uncacheable/tags');
     $this->assertEqual('MISS', $this->drupalGetHeader(DynamicPageCacheSubscriber::HEADER), 'By default, Drupal has no auto-placeholdering cache tags.');
+
+    // Finally, controllers returning render arrays without a top-level #cache
+    // trigger an exception urging the developer to add cacheability metadata.
+    $this->drupalGet(Url::fromRoute('dynamic_page_cache_test.html_without_cacheability'));
+    $this->assertResponse(200);
+    $this->assertRaw("The controller for the route 'dynamic_page_cache_test.html_without_cacheability' returned a render array without cacheability metadata. See https://www.drupal.org/developing/api/8/render/arrays/cacheability.");
   }
 
 }
diff --git a/core/modules/dynamic_page_cache/tests/dynamic_page_cache_test/dynamic_page_cache_test.routing.yml b/core/modules/dynamic_page_cache/tests/dynamic_page_cache_test/dynamic_page_cache_test.routing.yml
index 77125b6..1b06b47 100644
--- a/core/modules/dynamic_page_cache/tests/dynamic_page_cache_test/dynamic_page_cache_test.routing.yml
+++ b/core/modules/dynamic_page_cache/tests/dynamic_page_cache_test/dynamic_page_cache_test.routing.yml
@@ -73,3 +73,10 @@ dynamic_page_cache_test.html.uncacheable.tags:
     _controller: '\Drupal\dynamic_page_cache_test\DynamicPageCacheTestController::htmlUncacheableTags'
   requirements:
     _access: 'TRUE'
+
+dynamic_page_cache_test.html_without_cacheability:
+  path: '/dynamic-page-cache-test/html-without-cacheability'
+  defaults:
+    _controller: '\Drupal\dynamic_page_cache_test\DynamicPageCacheTestController::htmlWithoutCacheability'
+  requirements:
+    _access: 'TRUE'
diff --git a/core/modules/dynamic_page_cache/tests/dynamic_page_cache_test/src/DynamicPageCacheTestController.php b/core/modules/dynamic_page_cache/tests/dynamic_page_cache_test/src/DynamicPageCacheTestController.php
index b11984e..9550a45 100644
--- a/core/modules/dynamic_page_cache/tests/dynamic_page_cache_test/src/DynamicPageCacheTestController.php
+++ b/core/modules/dynamic_page_cache/tests/dynamic_page_cache_test/src/DynamicPageCacheTestController.php
@@ -45,12 +45,12 @@ public function cacheableResponse() {
   }
 
   /**
-   * A route returning a render array (without cache contexts, so cacheable).
+   * A route returning a render array without #cache.
    *
    * @return array
    *   A render array.
    */
-  public function html() {
+  public function htmlWithoutCacheability() {
     return [
       'content' => [
         '#markup' => 'Hello world.',
@@ -59,6 +59,16 @@ public function html() {
   }
 
   /**
+   * A route returning a render array (without cache contexts, so cacheable).
+   *
+   * @return array
+   *   A render array.
+   */
+  public function html() {
+    return $this->htmlWithoutCacheability() + ['#cache' => []];
+  }
+
+  /**
    * A route returning a render array (with cache contexts, so cacheable).
    *
    * @param \Symfony\Component\HttpFoundation\Request $request