commit https://github.com/vim/vim/commit/ffec3c53496d49668669deabc0724ec78e2274fd Author: Bram Moolenaar <Bram@vim.org> Date: Wed Mar 23 20:55:42 2016 +0100 patch 7.4.1640 Problem: Crash when an autocommand changes a quickfix list. (Dominique) Solution: Check wether an entry is still valid. (Yegappan Lakshmanan, Hirohito Higashi)

" Settings for test script execution
" Always use "COMMAND.COM", don't use the value of "$SHELL".
set shell=c:\COMMAND.COM shellquote= shellxquote= shellcmdflag=/c shellredir=>
" This is used only when the +eval feature is available.
if executable("cmd.exe")
   set shell=cmd.exe
endif