diff -u b/core/lib/Drupal/Core/Cache/Context/CacheContextsManager.php b/core/lib/Drupal/Core/Cache/Context/CacheContextsManager.php
--- b/core/lib/Drupal/Core/Cache/Context/CacheContextsManager.php
+++ b/core/lib/Drupal/Core/Cache/Context/CacheContextsManager.php
@@ -109,17 +109,15 @@
     $optimized_tokens = $this->optimizeTokens($context_tokens);
     // Iterate through cache contexts that has been optimized away and get their
     // cacheable metadata.
-    if ($cacheable_metadata) {
-      foreach (static::parseTokens(array_diff($context_tokens, $optimized_tokens)) as $context_token) {
-        list($context_id, $parameter) = $context_token;
-        if (!in_array($context_id, $this->contexts)) {
-          throw new \InvalidArgumentException(SafeMarkup::format('"@context" is not a valid cache context ID.', ['@context' => $context_id]));
-        }
-        $context = $this->getService($context_id);
-        // To make it possible to return NULL instead of CacheableMetadata.
-        if ($metadata = $context->getCacheableMetadata($parameter)) {
-          $cacheable_metadata = $cacheable_metadata->merge($metadata);
-        }
+    foreach (static::parseTokens(array_diff($context_tokens, $optimized_tokens)) as $context_token) {
+      list($context_id, $parameter) = $context_token;
+      if (!in_array($context_id, $this->contexts)) {
+        throw new \InvalidArgumentException(SafeMarkup::format('"@context" is not a valid cache context ID.', ['@context' => $context_id]));
+      }
+      $context = $this->getService($context_id);
+      // To make it possible to return NULL instead of CacheableMetadata.
+      if ($metadata = $context->getCacheableMetadata($parameter)) {
+        $cacheable_metadata = $cacheable_metadata->merge($metadata);
       }
     }
 
only in patch2:
unchanged:
--- a/core/modules/views/src/Plugin/views/cache/CachePluginBase.php
+++ b/core/modules/views/src/Plugin/views/cache/CachePluginBase.php
@@ -211,7 +211,7 @@ public function generateResultsKey() {
         'items_per_page' => $this->view->getItemsPerPage(),
         'offset' => $this->view->getOffset(),
       ];
-      $key_data += \Drupal::service('cache_contexts_manager')->convertTokensToKeys($this->displayHandler->getCacheMetadata()['contexts']);
+      $key_data += \Drupal::service('cache_contexts_manager')->convertTokensToKeys($this->displayHandler->getCacheMetadata()['contexts'])->getKeys();
 
       $this->resultsKey = $this->view->storage->id() . ':' . $this->displayHandler->display['id'] . ':results:' . hash('sha256', serialize($key_data));
     }