# Parse a super class declaration
	# Fatal error if the `string` is not a syntactically correct super class declaration
	fun parse_superclass(string: String): APropdef
	do
		var mod_string = "class Dummy\nsuper {string}\nend"
		var nclassdef = parse_classdef(mod_string).as(AStdClassdef)
		var nsuperclasses = nclassdef.n_propdefs
		if nsuperclasses.length != 1 then
			self.fatal_error(null, "Fatal Error: not a super class declaration.")
			abort
		end
		return nsuperclasses.first
	end