# Fire a fatal error about an unexpected character.
	#
	# Return `false`.
	fun fire_unexpected_char(rest_of_message: String): Bool do
		if is_xml_char then
			return fire_fatal_error("Unexpected character `{last_char.code_point.to_s}`{rest_of_message}.")
		else if eof then
			return fire_fatal_error("Unexpected end of file{rest_of_message}.")
		else
			return fire_fatal_error("Forbidden character.")
		end
	end