Sets: officially ordered
Officially, set elements have uncertain order. This predades when Hash started being ordered (Ruby 1.9.0, Xmas 2007). Sets have since been de-facto insertion-ordered. FYI, in those 13 years, there have been about 70 commits to
I have the impression that a non-negligible amount of code in the wild rely on sets being ordered, at least under most circumstances. I feel that this should be officialized.
If sets are truly unordered, then why do we hesitate to make an optimization of
See also: https://bugs.ruby-lang.org/issues/14069