vim-patch:8.2.4026: ml_get error with specific win_execute() command

Problem:    ml_get error with specific win_execute() command. (Sean Dewar)
Solution:   Check cursor and Visual area are OK.
e664a32701

src/nvim/eval/funcs.c

@@ -2193,6 +2193,13 @@ static void f_win_execute(typval_T *argvars, typval_T *rettv, FunPtr fptr)
     if (win_valid(wp) && !equalpos(curpos, wp->w_cursor)) {
       wp->w_redr_status = true;
     }
+
+    // In case the command moved the cursor or changed the Visual area,
+    // check it is valid.
+    check_cursor();
+    if (VIsual_active) {
+      check_pos(curbuf, &VIsual);
+    }
   }
 }
 

src/nvim/testdir/test_execute_func.vim

@@ -152,8 +152,23 @@ func Test_win_execute_visual_redraw()
   call setline(1, ['a', 'b', 'c'])
   new
   wincmd p
+  " start Visual in current window, redraw in other window with fewer lines
   call feedkeys("G\<C-V>", 'txn')
   call win_execute(winnr('#')->win_getid(), 'redraw')
+  call feedkeys("\<Esc>", 'txn')
+  bwipe!
+  bwipe!
+
+  enew
+  new
+  call setline(1, ['a', 'b', 'c'])
+  let winid = win_getid()
+  wincmd p
+  " start Visual in current window, extend it in other window with more lines
+  call feedkeys("\<C-V>", 'txn')
+  call win_execute(winid, 'call feedkeys("G\<C-V>", ''txn'')')
+  redraw
+
   bwipe!
   bwipe!
 endfunc