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gelisam/Regression.hs

Created May 3, 2014 17:58
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RankNTypes Regression
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Regression.hs
{-# LANGUAGE RankNTypes #-}
applyId :: (forall a. a -> a) -> b -> b
applyId f = f
passes :: [b] -> [b]
passes = map (applyId id)
-- works with ghc 7.6, fails with ghc 7.8
fails :: [b] -> [b]
fails = (map . applyId) id
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