From 30b58becf1dfe7ed6755542ecb1a587f0e0d1375 Mon Sep 17 00:00:00 2001 From: Rob Rix Date: Thu, 31 Mar 2016 15:04:33 -0400 Subject: [PATCH] Handle the Nothing/Nothing case. --- src/Data/Align.hs | 1 + 1 file changed, 1 insertion(+) diff --git a/src/Data/Align.hs b/src/Data/Align.hs index 67194feec..19079e9bf 100644 --- a/src/Data/Align.hs +++ b/src/Data/Align.hs @@ -33,6 +33,7 @@ instance Align Maybe where align (Just a) (Just b) = Just (These a b) align Nothing (Just b) = Just (That b) align (Just a) Nothing = Just (This a) + align _ _ = Nothing -- | A functor which can be traversed through an `Align`able functor, inverting the nesting of one in the other, given some default value. -- |