At
https://github.com/nordlow/phobos-next/blob/master/src/variant_pointer.d
I've implemented a pointer-only version of Variant called
VariantPointer.
I plan to use it to construct light-weight polymorphism in trie
containers for D I'm currently writing.
VariantPointer uses the top N-bits (N currently 8) to encode the
type pointed to be the untyped-pointer encoded in the 64-N bits
lower bits.
My question is:
It safe to assume that `typeBits` most significant bits of a
pointer on a 64-bit system are always zero?
Note that I didn't want to use the lower bits because I'm
currently unsure whether I need to represent stack-pointers
aswell.
