From ee3389e3bf67eb6742ea0e8ae99f901a2cca3b4b Mon Sep 17 00:00:00 2001
From: Shingo Kitagawa <shingogo@hotmail.co.jp>
Date: Wed, 15 Dec 2021 01:47:00 +0900
Subject: [PATCH 1/2] show warning message if copy-tree with non list

---
 lisp/l/common.l | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lisp/l/common.l b/lisp/l/common.l
index 4c2c22520..b6624fc28 100644
--- a/lisp/l/common.l
+++ b/lisp/l/common.l
@@ -433,7 +433,10 @@ if pos is bigger than the length of list, item is nconc'ed at the tail"
 (defun last (x)
   (while (consp (cdr x)) (setq x (cdr x)))
   x)
-(defun copy-tree (x) (subst t t x))
+(defun copy-tree (x)
+  (if (not (listp x))
+    (warning-message 1 "copy-tree should be used with list: ~A~%" x))
+  (subst t t x))
 (defun copy-list (x) (nreverse (reverse x)))
 (defun nreconc (x y) (nconc (nreverse x) y))
 (defun rassoc (item alist)

From e602258e59d1b1b2f62349a5ac959aca9c3a1c06 Mon Sep 17 00:00:00 2001
From: Shingo Kitagawa <shingogo@hotmail.co.jp>
Date: Wed, 15 Dec 2021 19:28:34 +0900
Subject: [PATCH 2/2] add warning in copy-tree manual

---
 doc/jlatex/jsequences.tex | 6 +++++-
 doc/latex/sequences.tex   | 5 ++++-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/doc/jlatex/jsequences.tex b/doc/jlatex/jsequences.tex
index 6780e5ffb..37c58123d 100644
--- a/doc/jlatex/jsequences.tex
+++ b/doc/jlatex/jsequences.tex
@@ -396,7 +396,11 @@ \subsection{リスト}
 入れこリストである{\em tree}のコピーを返す。
 しかし、環状参照はできない。環状リストは、
 {\bf copy-object}でコピーできる。
-実際に、{\bf copy-tree}は{\tt (subst t t tree)}と簡単に記述される。}
+実際に、{\bf copy-tree}は{\tt (subst t t tree)}と簡単に記述される。
+なお{\bf copy-tree}は{\em list}しかコピーできず、
+{\em integer-vector, float-vector}などは{\bf copy-seq}を使用しないとコピーできず、
+{\em interger-vector, float-vector}などを含む{\em list}は{\bf copy-object}を
+使用しないとディープコピーできない。}
 
 \funcdesc{mapc}{func arg-list \&rest more-arg-lists}{
 {\em arg-list}や{\em more-arg-lists}それぞれのN番目($N=0,1,\cdots$)の要素からなるリストに
diff --git a/doc/latex/sequences.tex b/doc/latex/sequences.tex
index ab94ba857..fbd75c0f0 100644
--- a/doc/latex/sequences.tex
+++ b/doc/latex/sequences.tex
@@ -393,7 +393,10 @@ \subsection{Lists}
 returns the copy of {\em tree} which may be a nested list
 but cannot have circular reference. Circular lists can be copied by
 {\bf copy-object}.
-Actually, {\bf copy-tree} is simply coded as {\tt (subst t t tree)}.}
+Actually, {\bf copy-tree} is simply coded as {\tt (subst t t tree)}.
+Be careful that {\bf copy-tree} only return the copy of {\em list}.
+and you need to use {\bf copy-seq} to copy {\em integer-vector, float-vector}, etc.,
+or {\bf copy-object} to deep-copy {\em list} with {\em integer-vector, float-vector} etc.}
 
 \funcdesc{mapc}{func arg-list \&rest more-arg-lists}{
 applies {\em func} to a list of N-th elements in {\em arg-list} and each of