Red-Black tree storing color without additional memory requirements

[safety0ff]

On Wednesday, 20 November 2013 at 08:48:33 UTC, simendsjo wrote:
> But I would think this trick would break the GC, as well as 
> making code less portable.

Since the GC supports interior pointers, I think you can justify 
using the least significant bits as long as the size and 
alignment of the pointed object guarantee that the pointer + tag 
will always lie inside the memory block.