Zero-sized data structures are not initialised in MIR

I played around a bit with empty data structures ((), [usize;0] , and struct EmptyStruct(), which all don't require any stored bytes...
Interestingly, the MIR I am getting somewhat relies on the fact that there are no stored bytes for these. I have a program like this (example: (), but the same happens for the other types):

const EMPTY: () = ();
fn main() {
    let e = ();
    assert!(e == EMPTY);
}

The first statement in main (block 0, first statement) becomes _3 <- &_1. which assumes there is nothing to do to initialise _1 to be ().
That assumption is untrue for our semantics, though, where () is represented as Aggregate(variantIdx(0), .List) but we get newValue(...) in _1 and end up with a reference pointing to it in _3.
For my 3 programs with empty data I did not find any point where that reference would be Dereferenced but I cannot be sure. The eq instances for () and EmptyStruct() just return constant true but the one for [usize;0] blindly calls the raw_eq intrinsic.
We should adapt our forthcoming implementation of raw_eq to this.

Reproduce the three examples involving (), [usize; 0], and EmptyStruct(), then inspect the generated MIR where _1 is assigned and _3 takes a reference to it. Read the planned raw_eq implementation and determine how zero-sized Aggregate values should be initialized and compared. Done means the examples no longer rely on an uninitialized zero-sized value.