Environment

• fish --version
  fish, version 3.5.0

• uname -a
  Darwin Egoist 21.5.0 Darwin Kernel Version 21.5.0: Tue Apr 26 21:08:37 PDT 2022; root:xnu-8020.121.3~4/RELEASE_ARM64_T6000 arm64

• $TERM
  xterm-256color
  Also happens with Alacritty, Kitty, Terminal.app

• Issue also affects fish without third party customization

Issue

I believe this is similar, yet an edge case of #4570 .

the backslash bug only occurs when autocompleting something that require escaping without the user escaping it themselves.

to reproduce, run the following commands:

mkdir ~/fish_bug
cd ~/fish_bug
touch '[Hello]World.txt'
vim ~/fish_bug/[ **Tab**           <--- Notice that I deliberately did not escape the bracket.

result: vim \~/fish_bug/[Hello]\ World.txt

expected result: vim ~/fish_bug/[Hello]\ World.txt