diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -6836,6 +6836,7 @@
       'PhabricatorCustomFieldInterface',
       'PhabricatorDestructibleInterface',
       'PhabricatorSSHPublicKeyInterface',
+      'PhabricatorFlaggableInterface',
       'PhabricatorApplicationTransactionInterface',
     ),
     'PhabricatorUserBlurbField' => 'PhabricatorUserCustomField',
diff --git a/src/applications/people/storage/PhabricatorUser.php b/src/applications/people/storage/PhabricatorUser.php
--- a/src/applications/people/storage/PhabricatorUser.php
+++ b/src/applications/people/storage/PhabricatorUser.php
@@ -14,6 +14,7 @@
     PhabricatorCustomFieldInterface,
     PhabricatorDestructibleInterface,
     PhabricatorSSHPublicKeyInterface,
+    PhabricatorFlaggableInterface,
     PhabricatorApplicationTransactionInterface {
 
   const SESSION_TABLE = 'phabricator_session';