Is interning as a general primitive something that should be in the standard library?

Thank you for the feedback, Mr. robofinch.

To clarify: I was not suggesting that Vec belongs in core. The mention of slice and Vec was just to say they are not what here I wanted.

You are right that I was imprecise about core vs alloc. Since the implementation relies on alloc, the more accurate claim is that these concepts are absent from core/alloc, and if they were to be added anywhere, alloc would be the appropriate place. That was my mistake.

Thank you again for taking the time to respond.