vim-patch:8.2.4215: illegal memory access when copying lines in Visual mode

Problem:    Illegal memory access when copying lines in Visual mode.
Solution:   Adjust the Visual position after copying lines.
dc5490e2cb

src/nvim/ex_cmds.c

@@ -1099,6 +1099,9 @@ void ex_copy(linenr_T line1, linenr_T line2, linenr_T n)
   }
 
   appended_lines_mark(n, count);
+  if (VIsual_active) {
+    check_pos(curbuf, &VIsual);
+  }
 
   msgmore((long)count);
 }

src/nvim/testdir/test_visual.vim

@@ -1151,5 +1151,16 @@ func Test_visual_reselect_with_count()
   call delete('XvisualReselect')
 endfunc
 
+" this was leaving the end of the Visual area beyond the end of a line
+func Test_visual_ex_copy_line()
+  new
+  call setline(1, ["aaa", "bbbbbbbbbxbb"])
+  /x
+  exe "normal ggvjfxO"
+  t0
+  normal gNU
+  bwipe!
+endfunc
+
 
 " vim: shiftwidth=2 sts=2 expandtab