REF: use fused types in hashtables
This just gets the helper functions.  Getting the rest is more difficult.
does this have any perf impact? > does this have any perf impact?

will let you know in ~8 hours This appears to cause a significant slowdown in `duplicated`.  Will look into this. > This appears to cause a significant slowdown in `duplicated`. Will look into this.

k great thanks for running the asvs Closing to clear the queue while i figure this out locally