This variant of the server in net/rpc/server_test.go works fine:

type args struct {
    A, B int
}

type reply struct {
    C int
}

type arith struct {
    Nothing int
}

func (t *arith) Add(args args, reply *reply) error {
    reply.C = args.A + args.B
    return nil
}


if we use RegisterName("Arith", new(arith)) and disable the export checks in
server.go.  Since those checks are there for early identification of problematic
methods, it makes sense to relax this restriction. However, it can't be done before Go 1
because methods might become RPC-able that are not currently, and that's an unwise
change to make at this point.