diff --git a/src/applications/files/iconset/PhabricatorIconSet.php b/src/applications/files/iconset/PhabricatorIconSet.php
index baf5422375..c31c3e11fc 100644
--- a/src/applications/files/iconset/PhabricatorIconSet.php
+++ b/src/applications/files/iconset/PhabricatorIconSet.php
@@ -3,6 +3,8 @@
 abstract class PhabricatorIconSet
   extends Phobject {
 
+  abstract protected function newIcons();
+
   final public function getIconSetKey() {
     return $this->getPhobjectClassConstant('ICONSETKEY');
   }