haskell/containers — pull request #68 by treeowl (2014-11-17 22:56:37+00:00)
Title: Improve Foldable methods

Define `foldMap` for `Seq` directly, instead of relying on the default
based on `foldr`.

Define `length` and `null` for `ViewR` directly, instead of relying on
(inappropriate) defaults.