patch 8.2.3704: Vim9: cannot use a list declaration in a :def function Commit: https://github.com/vim/vim/commit/ab36e6ae7b87b0295fb19270e4339a734875c6b1 Author: Bram Moolenaar <Bram@vim.org> Date: Tue Nov 30 16:14:49 2021 +0000 patch 8.2.3704: Vim9: cannot use a list declaration in a :def function Problem: Vim9: cannot use a list declaration in a :def function. Solution: Make it work.

" 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