patch 8.2.2157: Vim9: can delete a Vim9 script variable from a function Commit: https://github.com/vim/vim/commit/9aed729fe9e62536236875a42fb170d2c8fb3046 Author: Bram Moolenaar <Bram@vim.org> Date: Fri Dec 18 15:38:00 2020 +0100 patch 8.2.2157: Vim9: can delete a Vim9 script variable from a function Problem: Vim9: can delete a Vim9 script variable from a function. Solution: Check the variable is defined in Vim9 script. (closes https://github.com/vim/vim/issues/7483)

" Vim filetype plugin file
" Language:             mutt RC File
" Previous Maintainer:  Nikolai Weibull <now@bitwi.se>
" Latest Revision:      2006-04-19

if exists("b:did_ftplugin")
  finish
endif
let b:did_ftplugin = 1

let s:cpo_save = &cpo
set cpo&vim

let b:undo_ftplugin = "setl com< cms< inc< fo<"

setlocal comments=:# commentstring=#\ %s
setlocal formatoptions-=t formatoptions+=croql

let &l:include = '^\s*source\>'

let &cpo = s:cpo_save
unlet s:cpo_save