Without lifetime tracking, ranges pose a number of issues with regards
to memory safety - use openArray instead which is limited but safe.
In its present form, ranges take a copy of whatever is passed to them
which obscures the copies that they take, leading to misleading and slow
code.
If openArray is not applicable, simply do a seq copy - it's fine and
really doesn't matter in 95% of all cases, then profile and use other
techniques where needed.
Jacek Sieka