diff --git a/dtrt-indent.el b/dtrt-indent.el
index a522ed0..af0ba22 100644
--- a/dtrt-indent.el
+++ b/dtrt-indent.el
@@ -197,6 +197,7 @@ adjusted transparently."
   (if dtrt-indent-mode
       (if (and (boundp 'smie-grammar) (not (null smie-grammar)) (not (eq smie-grammar 'unset)))
           (progn
+            ;; FIXME: Emacs warns about unbound identifiers: https://github.com/jscheid/dtrt-indent/issues/79
             (when (null smie-config--buffer-local) (smie-config-guess))
             (when dtrt-indent-run-after-smie
               (dtrt-indent-try-set-offset)))