Idea: keyword gate annotation #![keywords(...)]

My apologies, Steve. In my haste to write this up, I didn't include the feedback you and others provided in the throw/fail PR. I updated the FP with links to each person's initial response to the idea.

This was one of the original models we proposed for editions generally, but was rejected. What’s changed since then? It’d be worth re-exploring.

I agree we should explore this more deeply. The motivation section, above, provides the seed for such a discussion: Keyword reservation is supposed to be a way to defer argument, but we ended up having the argument anyway, with greater time pressure.

I’m also very wary of doing this now.

To be clear: I don't know if I want this feature at all, and I certainly don't want to add it now. What I'm after is twofold:

  • seeding the discussion, so that if there's a need to revise the policy, it can incorporate the 2018 edition's lived experience.
  • providing a topic to discuss keyword reservation policy, so that threads like Reserve `never` for 2018 epoch can focus on the technical merits.

In service of those ends, the above idea is intentionally light on the details.