Clarify lexvar restrictions for add-to-ordered-list, add-to-history

* lisp/subr.el (add-to-ordered-list, add-to-history):
* doc/lispref/lists.texi (List Variables):
* doc/lispref/minibuf.texi (Minibuffer History):
Note in the doc string and manual that the variable arguments to
add-to-ordered-list and add-to-history cannot refer to a lexical
variable (bug#39373).

1 files changed, 3 insertions, 1 deletions

diff --git a/lisp/subr.el b/lisp/subr.el
index 05fb82321e5..c1c4cad18d1 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -1935,6 +1935,7 @@ of ELEMENT if it has one.
 
 The list order for each element is stored in LIST-VAR's
 `list-order' property.
+LIST-VAR cannot refer to a lexical variable.
 
 The return value is the new value of LIST-VAR."
   (let ((ordering (get list-var 'list-order)))
@@ -1963,7 +1964,8 @@ variable.  The possible values of maximum length have the same meaning as
 the values of `history-length'.
 Remove duplicates of NEWELT if `history-delete-duplicates' is non-nil.
 If optional fourth arg KEEP-ALL is non-nil, add NEWELT to history even
-if it is empty or duplicates the most recent entry in the history."
+if it is empty or duplicates the most recent entry in the history.
+HISTORY-VAR cannot refer to a lexical variable."
   (unless maxelt
     (setq maxelt (or (get history-var 'history-length)
                      history-length)))