commit https://github.com/vim/vim/commit/f609dcf8c1094f6fc95f4fc36321a1fb08a7110c Author: Bram Moolenaar <Bram@vim.org> Date: Thu Dec 3 17:43:17 2015 +0100 patch 7.4.954 Problem: When using Lua there may be a crash. (issue https://github.com/vim/vim/issues/468) Solution: Avoid using an unitialized tv. (Yukihiro Nakadaira)

" 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