commit https://github.com/vim/vim/commit/8f79acdf7ede2693fbda53c3c9693f16db4f193b Author: Bram Moolenaar <Bram@vim.org> Date: Fri Jan 1 14:48:20 2016 +0100 patch 7.4.1017 Problem: When there is a backslash in an option ":set -=" doesn't work. Solution: Handle a backslash better. (Jacob Niehus) Add a new test, merge in old test.

Tests for writefile()

STARTTEST
:source small.vim
:%delete _
:let f = tempname()
:call writefile(["over","written"], f, "b")
:call writefile(["hello","world"], f, "b")
:call writefile(["!", "good"], f, "a")
:call writefile(["morning"], f, "ab")
:call writefile(["", "vimmers"], f, "ab")
:bwipeout!
:$put =readfile(f)
:1 delete _
:w! test.out
:qa!
ENDTEST