The hash value of ordered sets is order-dependent

[willow-ahrens]

hash(OrderedSet([1, 2])) != hash(OrderedSet([2, 1])). This can lead to surprising bugs when using ordered sets as keys in dictionaries.

[willow-ahrens]

Also note that isequal(OrderedSet([1, 2]), OrderedSet([2, 1])) is true. https://github.com/JuliaLang/julia/blob/5c869cd363da605f51454be03c98fe4c1ec4ba5b/base/hashing.jl#L5-L16

[willow-ahrens]

I think this should also get fixed for all the other types in this repo, is that right?