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snoyberg / mono-traversable

Type classes for mapping, folding, and traversing monomorphic containers
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Eq key => SetContainer [key] #135

Closed jchia closed 7 years ago

jchia commented 7 years ago

Is there an intrinsic reason for having an instance Eq key => SetContainer [(key, value)] but not Eq key => SetContainer [key]? Because of this missing instance, ClassyPrelude.(\\) can't do the same thing as Data.List.(\\).

snoyberg commented 7 years ago

The instance is impossible without something like OverlappingInstances, which would be a bad thing to add.