# The rank of the main ellipsis (`...`) for vararg (starting from 0).
	# value is -1 if there is no vararg.
	# Example: for "(a: Int, b: Bool..., c: Char)" #-> vararg_rank=1
	#
	# From a model POV, a signature can contain more than one vararg parameter,
	# the `vararg_rank` just indicates the one that will receive the additional arguments.
	# However, currently, if there is more that one vararg parameter, no one will be the main one,
	# and additional arguments will be refused.
	var vararg_rank: Int is noinit