zsh-users/zsh-syntax-highlighting — pull request #133 by lucc (2013-11-04 23:56:15+00:00)
Title: protect alias expansion from interpreting aliases as options

If one defines aliases like `++` the alias builtin tries to interprete these
as options so they have to be protected like this

alias -- ++=true

The same goes for a call to `alias` in order to expand the alias again.