patch 8.1.1357: test 37 is old style commit https://github.com/vim/vim/commit/999dc14644b8a9530ce0da22e90ca402c95c9c5a Author: Bram Moolenaar <Bram@vim.org> Date: Sun May 19 21:44:08 2019 +0200 patch 8.1.1357: test 37 is old style Problem: Test 37 is old style. Solution: Turn it into a new style test. (Yegappan Lakshmanan, closes https://github.com/vim/vim/issues/4398)

" Simplistic way to make spaces and Tabs visible

" This can be added to an already active syntax.

syn match Space " "
syn match Tab "\t"
if &background == "dark"
  hi def Space ctermbg=darkred guibg=#500000
  hi def Tab ctermbg=darkgreen guibg=#003000
else
  hi def Space ctermbg=lightred guibg=#ffd0d0
  hi def Tab ctermbg=lightgreen guibg=#d0ffd0
endif