From the maintainer Li Haoyi: I'm putting a 300USD bounty on this issue, payable by bank transfer on a merged PR implementing this.

See https://github.com/orgs/com-lihaoyi/discussions/6 for other bounties and the terms and conditions that bounties operate under

Following the final implementation of scala/improvement-proposals#78, we should only allow @unroll on methods that are final, or on an object (which is final), or on a final class.

@unroll on constructors and case classes are not affected, since the <init> and apply companion methods are already final