diff -u b/core/modules/openid/openid.module b/core/modules/openid/openid.module
--- b/core/modules/openid/openid.module
+++ b/core/modules/openid/openid.module
@@ -6,7 +6,7 @@
  */
 
 use Guzzle\Http\Exception\RequestException;
-use Drupal\block\BlockInterface;
+use Drupal\block\BlockPluginInterface;
 
 /**
  * Implements hook_menu().
@@ -167,7 +167,7 @@
  *
  * @see \Drupal\user\Plugin\block\block\UserLoginBlock
  */
-function openid_block_view_user_login_block_alter(array &$build, BlockInterface $block) {
+function openid_block_view_user_login_block_alter(array &$build, BlockPluginInterface $block) {
   // Only alter the block when it is non-empty, i.e. when no user is logged in.
   if (!isset($build['content']['user_login_form'])) {
     return;