We already have a reverse function for the rawValue property; every RawRepresentable type gets a failable initializer init?(rawValue: Self.RawValue).

As for {{allValues}, I'd like to point out that this could only be done for C-like enums (enums without associated values). It's also not obvious how it should work; does it return an Array or some lazy generator? If it returns an Array, does it generate one on every call, or does it save it as a static value? Generating it on every call has performance implications, but saving it as a static value takes memory. Furthermore, once you have an allValues list, the next natural thing to want is some way to get the previous/next variant from a given variant, but does it actually make sense to do that? Also, making any change like this means automatically adding a member to all C-like enums even when they don't declare any protocol conformance, which may be undesired (maybe I want to have an allValues member that returns something else, e.g. if I have variants in my enum that aren't truly "values" but are instead things like bitmasks if my enum is a set of bitflags).

It seems to me that swift-evolution is the right place to discuss the allValues suggestion.

CodaFi (JIRA User), found this issue. Hasn't it been fixed recently?

Yep. Addressed by the merge of #13655.

Swift evolution proposal: SE-0194.