GetFieldValue has: public class GetFieldValue extends VDLFunction { [...] public static final Arg PA_VAR1 = new Arg.Positional("var"); and also inherits from VDLFunction: public static final Arg PA_VAR = new Arg.Positional("var"); >From the name, it looks like PA_VAR1 was deliberately made to not be PA_VAR but I don't really understand why. --