Control.Parallel.Strategies: definitions of rnf for most collections are poor

These all perform a lot of consing, which seems rather undesirable. It would be very nice indeed if they could be rebaked in terms of strict left folds. Unfortunately, all of the collections in question seem only to expose non-strict left folds publicly.

instance (NFData k, NFData a) => NFData (Data.Map.Map k a) where
    rnf = rnf . Data.Map.toList

instance NFData a => NFData (Data.Set.Set a) where
    rnf = rnf . Data.Set.toList

instance NFData a => NFData (Data.Tree.Tree a) where
    rnf (Data.Tree.Node r f) = rnf r `seq` rnf f

instance NFData a => NFData (Data.IntMap.IntMap a) where
    rnf = rnf . Data.IntMap.toList

instance NFData Data.IntSet.IntSet where
    rnf = rnf . Data.IntSet.toList

Trac metadata

Trac field	Value
Version	6.8.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	libraries/base
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system	Unknown
Architecture	Unknown