commit https://github.com/vim/vim/commit/c4dcd60c76666bf113719f929709ad6120eb6528 Author: Bram Moolenaar <Bram@vim.org> Date: Sat Mar 26 22:56:46 2016 +0100 patch 7.4.1662 Problem: No test for an invalid Ex command on a channel. Solution: Test handling an invalid command gracefully. Avoid getting an error message, do write it to the channel log.

" Vim compiler file
" Compiler:     ATT dot
" Maintainer:	Marcos Macedo <bar4ka@bol.com.br>
" Last Change:	2004 May 16

if exists("current_compiler")
  finish
endif
let current_compiler = "dot"

if exists(":CompilerSet") != 2		" older Vim always used :setlocal
  command -nargs=* CompilerSet setlocal <args>
endif

CompilerSet makeprg=dot\ -T$*\ \"%:p\"\ -o\ \"%:p:r.$*\"