RFC: tagged pointer

[deadalnix via Digitalmars-d]

Hi all,

There is something that is badly needed in std.butmanip : a way 
to create tagged pointers. It is doable safely by checking 
pointer alignment and allowing for n bits to be taken for various 
things.

This is something I want to do for ages (and need) but constantly 
run out of time. I think it would be useful to others as well.

Would someone champion it ?