patch 8.2.2846: Vim9: "echo Func()" does not give an error for using void Commit: https://github.com/vim/vim/commit/68db996b621b98066fb7ab7028ed5c6aaa3954a8 Author: Bram Moolenaar <Bram@vim.org> Date: Sun May 9 23:19:22 2021 +0200 patch 8.2.2846: Vim9: "echo Func()" does not give an error for using void Problem: Vim9: "echo Func()" does not give an error for a function without a return value. Solution: Give an error. Be more specific about why a value is invalid.

" Vim filetype plugin file
" Language:	Diff
" Maintainer:	Bram Moolenaar <Bram@vim.org>
" Last Change:	2020 Jul 18

" Only do this when not done yet for this buffer
if exists("b:did_ftplugin")
  finish
endif
let b:did_ftplugin = 1

let b:undo_ftplugin = "setl modeline<"

" Don't use modelines in a diff, they apply to the diffed file
setlocal nomodeline

" If there are comments they start with #
let &commentstring = "# %s"