InputRange for data structure without order?

[Monkyyy]

On Wednesday, 4 June 2025 at 02:11:18 UTC, H. S. Teoh wrote:
> . But in general, containers should NOT be conflated with 
> ranges. That only leads to wrong design.
>
> range should NOT mutate the container.  It should be regarded 
> as something separate from the container.

Not "general". It's a safety vs speed tradeoff. Immutable 
whatever's data structure do just make allot of copies or allot 
of pointer overhead and indirection.