1 files changed, 3 insertions, 2 deletions

diff --git a/lisp/shell.el b/lisp/shell.el
index 33a60fdedd9..369e0ac14d0 100644
--- a/lisp/shell.el
+++ b/lisp/shell.el
@@ -688,8 +688,9 @@ See `shell-dynamic-complete-filename'.  Returns t if successful."
          (paths (cdr (reverse exec-path)))
          (cwd (file-name-as-directory (expand-file-name default-directory)))
          (ignored-extensions
-          (mapconcat (function (lambda (x) (concat (regexp-quote x) "$")))
-                     comint-completion-fignore "\\|"))
+          (and comint-completion-fignore
+               (mapconcat (function (lambda (x) (concat (regexp-quote x) "$")))
+                          comint-completion-fignore "\\|")))
          (path "") (comps-in-path ()) (file "") (filepath "") (completions ()))
     ;; Go thru each path in the search path, finding completions.
     (while paths