scanl1 and scanr1: Does not fuse (branches on null t)

Author: nomeata

Data/Text.hs

@@ -1033,8 +1033,7 @@ scanl f z t = unstream (S.scanl g z (stream t))
 {-# INLINE scanl #-}
 
 -- | /O(n)/ 'scanl1' is a variant of 'scanl' that has no starting
--- value argument.  Subject to fusion.  Performs replacement on
--- invalid scalar values.
+-- value argument. Performs replacement on invalid scalar values.
 --
 -- > scanl1 f [x1, x2, ...] == [x1, x1 `f` x2, ...]
 scanl1 :: (Char -> Char -> Char) -> Text -> Text
@@ -1052,8 +1051,7 @@ scanr f z = S.reverse . S.reverseScanr g z . reverseStream
 {-# INLINE scanr #-}
 
 -- | /O(n)/ 'scanr1' is a variant of 'scanr' that has no starting
--- value argument.  Subject to fusion.  Performs replacement on
--- invalid scalar values.
+-- value argument. Performs replacement on invalid scalar values.
 scanr1 :: (Char -> Char -> Char) -> Text -> Text
 scanr1 f t | null t    = empty
            | otherwise = scanr f (last t) (init t)