Fixed weird struct problem from downs, see mini/compile_structs1.d Rewrote DtoIndexStruct/Class , the old implementation were way too complex for what we really need now - since the DotVar changes.

module aa5;

void main()
{
    int[int] aa;
    aa[42] = 1;
    int i = aa[42];
    assert(i == 1);
}