Zsh does not allow the variable name or the equals sign to be quoted or
escaped. The previous code incorrectly highlighted the following
examples as assignments:
$ 'x=y'
zsh: command not found: x=y
$ x\=y
zsh: command not found: x=y
$ "x"=y
zsh: command not found: x=y
$ \x=y
zsh: command not found: x=y
