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 bug52;
struct Vec { double x,y,z; }
struct Pair(T, U) { T first; U second; }
typedef Pair!(double, Vec) Hit;
void main() {}