Remove Foldable from Traversable (was Haskell Foldable Wats)

Jeremy voldermort at
Thu Feb 25 08:28:54 UTC 2016

Several suggestions have been made in this thread. The one with the highest
cost-to-benefit ratio would seem to be removing the Foldable constraint from
Traversable, as it is simply not required by the Traversable definition.
Lennart actually tried recompiling base with this "and it hardly needed any

I suggest that we consider this change first, as it brings the benefit of
allowing Traversable types without having to define possibly nonsensical
Foldable instances, and according to Lennart's experiment, has trivial

Lennart, what changes did you have to make? Anybody care to recompile their
pet project with this change and see if there's any significant impact?

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