aspect ZSdevirt {
	// A virtual method call is *ZSdevirt* if it is
	// devirtualizable according to the Zero Subclasses condition
	syn boolean VirtualMethodAccess.ZSdevirt() {
		TypeDecl F = isQualified() ? qualifier().type(): hostType(); // Formal type of receiver
		if (F instanceof ClassDecl) {
			return ((ClassDecl) F).subclasses().size()==0;
		}
		else return false;
	}
}