diff --git a/runtime/indent/hare.vim b/runtime/indent/hare.vim
index bc4fea4..0a9d8da 100644
--- a/runtime/indent/hare.vim
+++ b/runtime/indent/hare.vim
@@ -2,6 +2,7 @@
 " Language: Hare
 " Maintainer: Amelia Clarke <me@rsaihe.dev>
 " Last Change: 2022 Sep 22
+"              2023 Aug 28 by Vim Project (undo_indent)
 
 if exists("b:did_indent")
   finish
@@ -40,6 +41,8 @@
 
 setlocal indentexpr=GetHareIndent()
 
+let b:undo_indent = "setl cin< cino< cinw< inde< indk<"
+
 function! FloorCindent(lnum)
   return cindent(a:lnum) / shiftwidth() * shiftwidth()
 endfunction