diff --git a/src/evalwindow.c b/src/evalwindow.c
index 34d202e..672bfc1 100644
--- a/src/evalwindow.c
+++ b/src/evalwindow.c
@@ -808,7 +808,8 @@
     wp = find_win_by_nr_or_id(&argvars[0]);
     targetwin = find_win_by_nr_or_id(&argvars[1]);
 
-    if (wp == NULL || targetwin == NULL || wp == targetwin)
+    if (wp == NULL || targetwin == NULL || wp == targetwin
+	    || !win_valid(wp) || !win_valid(targetwin))
     {
         emsg(_(e_invalwindow));
 	rettv->vval.v_number = -1;
diff --git a/src/testdir/test_window_cmd.vim b/src/testdir/test_window_cmd.vim
index d543ef7..87c1f1f 100644
--- a/src/testdir/test_window_cmd.vim
+++ b/src/testdir/test_window_cmd.vim
@@ -927,6 +927,10 @@
   call assert_fails('call win_splitmove(winnr(), 123)', 'E957:')
   call assert_fails('call win_splitmove(123, winnr())', 'E957:')
   call assert_fails('call win_splitmove(winnr(), winnr())', 'E957:')
+
+  tabnew
+  call assert_fails('call win_splitmove(1, win_getid(1, 1))', 'E957:')
+  tabclose
 endfunc
 
 " vim: shiftwidth=2 sts=2 expandtab
diff --git a/src/version.c b/src/version.c
index 28590ad..36dee83 100644
--- a/src/version.c
+++ b/src/version.c
@@ -743,6 +743,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    93,
+/**/
     92,
 /**/
     91,