diff --git a/core/modules/block/block.module b/core/modules/block/block.module
index a08254a..8af67c9 100644
--- a/core/modules/block/block.module
+++ b/core/modules/block/block.module
@@ -175,7 +175,7 @@
  * @see block_menu()
  */
 function _block_themes_access($theme) {
-  return user_access('administer blocks') && drupal_theme_access($theme);
+  return Drupal::currentUser()->hasPermission('administer blocks') && drupal_theme_access($theme);
 }
 
 /**
diff --git a/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockAccessController.php b/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockAccessController.php
index 9990a2e..169a576 100644
--- a/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockAccessController.php
+++ b/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockAccessController.php
@@ -24,7 +24,7 @@
       return TRUE;
     }
     elseif (in_array($operation, array('update', 'delete'))) {
-      return user_access('administer blocks', $account);
+      return $account->hasPermission('administer blocks');
     }
   }
 
@@ -32,7 +32,7 @@
    * {@inheritdoc}
    */
   protected function checkCreateAccess(AccountInterface $account, array $context, $entity_bundle = NULL) {
-    return user_access('administer blocks', $account);
+    return $account->hasPermission('administer blocks');
   }
 
 }
diff --git a/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockFormController.php b/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockFormController.php
index eb58dd6..613c6c2 100644
--- a/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockFormController.php
+++ b/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockFormController.php
@@ -41,7 +41,8 @@
    */
   public function form(array $form, array &$form_state) {
     $block = $this->entity;
-
+    $account = \Drupal::currentUser();
+    
     if ($this->operation == 'edit') {
       // @todo Remove this once https://drupal.org/node/1981644 is in.
       drupal_set_title(t('Edit custom block %label', array('%label' => $block->label())), PASS_THROUGH);
@@ -106,14 +107,14 @@
         'js' => array(drupal_get_path('module', 'custom_block') . '/custom_block.js'),
       ),
       '#weight' => 20,
-      '#access' => $block->isNewRevision() || user_access('administer blocks'),
+      '#access' => $block->isNewRevision() || $account->hasPermission('administer blocks'),
     );
 
     $form['revision_information']['revision'] = array(
       '#type' => 'checkbox',
       '#title' => t('Create new revision'),
       '#default_value' => $block->isNewRevision(),
-      '#access' => user_access('administer blocks'),
+      '#access' => $account->hasPermission('administer blocks'),
     );
 
     // Check the revision log checkbox when the log textarea is filled in.
diff --git a/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockTypeAccessController.php b/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockTypeAccessController.php
index 95b74ac..150a688 100644
--- a/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockTypeAccessController.php
+++ b/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockTypeAccessController.php
@@ -24,7 +24,7 @@
       return TRUE;
     }
     elseif (in_array($operation, array('update', 'delete'))) {
-      return user_access('administer blocks', $account);
+      return $account->hasPermission('administer blocks');
     }
   }
 
@@ -32,7 +32,7 @@
    * {@inheritdoc}
    */
   protected function checkCreateAccess(AccountInterface $account, array $context, $entity_bundle = NULL) {
-    return user_access('administer blocks', $account);
+    return $account->hasPermission('administer blocks');
   }
 
 }
diff --git a/core/modules/block/custom_block/lib/Drupal/custom_block/Plugin/Block/CustomBlockBlock.php b/core/modules/block/custom_block/lib/Drupal/custom_block/Plugin/Block/CustomBlockBlock.php
index cdd7016..f6c69e6 100644
--- a/core/modules/block/custom_block/lib/Drupal/custom_block/Plugin/Block/CustomBlockBlock.php
+++ b/core/modules/block/custom_block/lib/Drupal/custom_block/Plugin/Block/CustomBlockBlock.php
@@ -132,7 +132,7 @@
           '%uuid' => $uuid,
           '!url' => url('block/add')
         )),
-        '#access' => user_access('administer blocks')
+        '#access' => \Drupal::currentUser()->hasPermission('administer blocks')
       );
     }
   }
diff --git a/core/modules/block/lib/Drupal/block/Access/BlockThemeAccessCheck.php b/core/modules/block/lib/Drupal/block/Access/BlockThemeAccessCheck.php
index 97b53d4..0c882cd 100644
--- a/core/modules/block/lib/Drupal/block/Access/BlockThemeAccessCheck.php
+++ b/core/modules/block/lib/Drupal/block/Access/BlockThemeAccessCheck.php
@@ -28,7 +28,7 @@
    */
   public function access(Route $route, Request $request) {
     $theme = $request->attributes->get('theme');
-    return (user_access('administer blocks') && drupal_theme_access($theme)) ? static::ALLOW : static::DENY;
+    return (\Drupal::currentUser()->hasPermission('administer blocks') && drupal_theme_access($theme)) ? static::ALLOW : static::DENY;
   }
 
 }
diff --git a/core/modules/block/lib/Drupal/block/BlockAccessController.php b/core/modules/block/lib/Drupal/block/BlockAccessController.php
index 85f449e..2271746 100644
--- a/core/modules/block/lib/Drupal/block/BlockAccessController.php
+++ b/core/modules/block/lib/Drupal/block/BlockAccessController.php
@@ -55,7 +55,7 @@
    */
   protected function checkAccess(EntityInterface $entity, $operation, $langcode, AccountInterface $account) {
     if ($operation != 'view') {
-      return user_access('administer blocks', $account);
+      return $account->hasPermission('administer blocks');
     }
 
     // Deny access to disabled blocks.
diff --git a/core/modules/block/tests/modules/block_test/lib/Drupal/block_test/Plugin/Block/TestBlockInstantiation.php b/core/modules/block/tests/modules/block_test/lib/Drupal/block_test/Plugin/Block/TestBlockInstantiation.php
index 96f60b2..db402cb 100644
--- a/core/modules/block/tests/modules/block_test/lib/Drupal/block_test/Plugin/Block/TestBlockInstantiation.php
+++ b/core/modules/block/tests/modules/block_test/lib/Drupal/block_test/Plugin/Block/TestBlockInstantiation.php
@@ -10,6 +10,7 @@
 use Drupal\block\BlockBase;
 use Drupal\block\Annotation\Block;
 use Drupal\Core\Annotation\Translation;
+use Drupal\Core\Session\AccountInterface;
 
 /**
  * Provides a basic block for testing block instantiation and configuration.
@@ -34,7 +35,7 @@
    * {@inheritdoc}
    */
   public function access() {
-    return user_access('access content');
+    return \Drupal::currentUser()->hasPermission('access content');
   }
 
   /**