# Visit all tokens between `current_token` and `target`.
	fun catch_up(target: nullable ANode) do
		if target == null then return
		if current_token == null then return
		var token: Token
		if target isa Token then
			token = target
		else if target isa Prod then
			token = target.first_token.as(not null)
		else
			abort
		end
		if current_token.location > token.location then return
		while current_token != token do visit current_token
	end