Discussion: Storable instances for tuples

It seems surprising that there are no Storable instances for tuple types. I would expect any tuple of Storable types to be Storable. To provide a sensible FFI experience, the order of the fields should be preserved. Since Storable generally aligns values, I believe elements should be aligned within tuples as well, in the default fashion used for C structs. We could offer a Packed newtype to override this behavior. Why store tuples like this, and not the way Data.Vector.Unboxed does? A moment's reflection will show that it simply can't. A Ptr is a single pointer and must remain one; there's no room in it to deal with multiple arrays or extra offset info.