patch 8.2.0422: crash when passing popup window to win_splitmove()

Problem:    Crash when passing popup window to win_splitmove(). (john Devin)
Solution:   Disallow moving a popup window. (closes #5816)

src/evalwindow.c

@@ -810,7 +810,8 @@ f_win_splitmove(typval_T *argvars, typval_T *rettv)
     targetwin = find_win_by_nr_or_id(&argvars[1]);
 
     if (wp == NULL || targetwin == NULL || wp == targetwin
-	    || !win_valid(wp) || !win_valid(targetwin))
+	    || !win_valid(wp) || !win_valid(targetwin)
+	    || win_valid_popup(wp) || win_valid_popup(targetwin))
     {
         emsg(_(e_invalwindow));
 	rettv->vval.v_number = -1;

src/testdir/test_popupwin.vim

@@ -3307,4 +3307,16 @@ func Test_popupwin_atcursor_far_right()
   set signcolumn&
 endfunc
 
+func Test_popupwin_splitmove()
+  vsplit
+  let win2 = win_getid()
+  let popup_winid = popup_dialog('hello', {})
+  call assert_fails('call win_splitmove(popup_winid, win2)', 'E957:')
+  call assert_fails('call win_splitmove(win2, popup_winid)', 'E957:')
+
+  call popup_clear()
+  bwipe
+endfunc
+
+
 " vim: shiftwidth=2 sts=2

src/version.c

@@ -738,6 +738,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    422,
 /**/
     421,
 /**/