foreach syntax, std.mixin

[dsimcha]

What are the chances that D gets auto tuple unpacking for foreach loops before
D2 goes gold?  In other words, it would be nice to write:

uint[] foo = [1,2,3,4,5];
uint[] bar = [6,7,8,9,10];

foreach(a, b; zip(foo, bar)) {
    // Does what you think it does.
}

Also, how about foreach over ranges with an index variable?  For example:

foreach(index, elem; chain(foo, bar)) {
   // Does what you think it does.
}

If these aren't going to happen, would it be worth having in Phobos a
std.mixin module (I've already considered such a thing a few times here) that
would allow someone writing a range to add goodies like these to structs and
classes with a single line of code?  For example:

struct MyRange {
    Tuple!(float, float) _front;
    bool _empty;

    typeof(_front) front() {
        return _front;
    }

    void popFront() {
        // do stuff.
    }

    bool empty() {
        return _empty;
    }

    mixin(UnpackTupleForeach);

    mixin(IndexForeach);
}

The mixin(UnpackTupleForeach) would make this work:
foreach(float float1, float float2; MyRange.init) {}

The mixin(IndexForeach) would make this work:
foreach(size_t index, float floatTuple; MyRange.init) {}

This would work via opApply, which some don't like for efficiency reasons.
It's been shown a while back that, while opApply does have some overhead, it's
pretty small and LDC actually optimizes it out.