diff --git a/lisp/shell.el b/lisp/shell.el
index 008fcc4c4e8..a9990f5d551 100644
--- a/lisp/shell.el
+++ b/lisp/shell.el
@@ -98,6 +98,7 @@
 (require 'comint)
 (require 'pcomplete)
 (eval-when-compile (require 'files-x)) ;with-connection-local-variables
+(require 'subr-x)
 
 ;;; Customization and Buffer Variables