🔥 the Coalescent instance over Both (Line a).

src/Line.hs

@@ -2,9 +2,7 @@
 module Line where
 
 import Control.Applicative
-import Data.Align
 import Data.Coalescent
-import Data.Functor.Both
 
 -- | A line of items or an empty line.
 data Line a = Line [a] | Closed [a]
@@ -55,6 +53,3 @@ instance Monoid (Line a) where
 instance Coalescent (Line a) where
   coalesce a b | isOpen a = pure (a `mappend` b)
                | otherwise = pure a <|> pure b
-
-instance Coalescent (Both (Line a)) where
- coalesce as bs = tsequenceL (pure (Line [])) (coalesce <$> as <*> bs)