alias tuples?

[Janice Caron]

We've got value tuples, and we've got type tuples. Could we also have
alias tuples?

Here's what I mean. Right now I can do:

struct A
{
    X x;
    Y y;
    Z z;

    mixin Serialize!(x,y,z);
}
A a;

template Serialize(alias x,alias y,alias z)
{
    void serialize()
    {
        x.serialize();
        y.serialize();
        z.serialize();
    }
}

where the types X, Y and Z all have a serialize() function (and so on
recursively for every object in need of serialization). Now it seems
to me, if I wanted to make Serialize!() variadic, I'd need not a value
tuple, nor a type tuple, but an "alias tuple". I'd want to be able to
write something like:

struct A
{
    X x;
    Y y;
    Z z;

    mixin Serialize!(this.aliastupleof); /* expands to (x,y,z) */
}
A a;

template Serialize(alias T...)
{
    void serialize()
    {
        foreach(a;T)
            a.serialize();
    }
}

Of course this won't work right now. The template won't compile
because (alias T...) has no meaning, and even if it did, structs don't
have an aliastupleof property.

Thoughts?