patch 8.2.1502: Vim9: can use += with a :let command at script level Commit: https://github.com/vim/vim/commit/122616d9c1b57f1e1f29f1151f8e26d24df9092a Author: Bram Moolenaar <Bram@vim.org> Date: Fri Aug 21 21:32:50 2020 +0200 patch 8.2.1502: Vim9: can use += with a :let command at script level Problem: Vim9: can use += with a :let command at script level. Solution: Give an error.

" Provide 'PrintVer' command to print the interface versions.

func s:print_ver(lang, ...)
  if has(a:lang)
    exec a:lang join(a:000)
  else
    echo 'N/A'
  endif
  echo ''
endfunc

command -nargs=+ PrintVer call <SID>print_ver(<f-args>)