From 42bde27d2b08ddfb79742d7eed6d9d0c34ea0256 Mon Sep 17 00:00:00 2001
From: Hussein Ait Lahcen <hussein.aitlahcen@gmail.com>
Date: Thu, 22 Mar 2018 17:56:46 +0100
Subject: [PATCH 1/2] fix: Zip/AsyncZip applicative instances

refact: type consistency

refact: introduce srepeat
---
 src/Streamly/Core.hs    | 4 ++++
 src/Streamly/Streams.hs | 4 ++--
 test/Main.hs            | 8 ++++++--
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/Streamly/Core.hs b/src/Streamly/Core.hs
index 7ed7362f..8a763111 100644
--- a/src/Streamly/Core.hs
+++ b/src/Streamly/Core.hs
@@ -25,6 +25,7 @@ module Streamly.Core
 
     -- * Construction
     , scons
+    , srepeat
     , snil
 
     -- * Composition
@@ -217,6 +218,9 @@ type MonadAsync m = (MonadIO m, MonadBaseControl IO m, MonadThrow m)
 scons :: a -> Maybe (Stream m a) -> Stream m a
 scons a r = Stream $ \_ _ yld -> yld a r
 
+srepeat :: a -> Stream m a
+srepeat a = let x = scons a (Just x) in x
+
 snil :: Stream m a
 snil = Stream $ \_ stp _ -> stp
 
diff --git a/src/Streamly/Streams.hs b/src/Streamly/Streams.hs
index fd3a2201..0e410766 100644
--- a/src/Streamly/Streams.hs
+++ b/src/Streamly/Streams.hs
@@ -751,7 +751,7 @@ instance Monad m => Functor (ZipStream m) where
         in m Nothing stp yield
 
 instance Monad m => Applicative (ZipStream m) where
-    pure a = ZipStream $ scons a Nothing
+    pure = ZipStream . srepeat
     (<*>) = zipWith id
 
 instance Streaming ZipStream where
@@ -838,7 +838,7 @@ instance Monad m => Functor (ZipAsync m) where
         in m Nothing stp yield
 
 instance MonadAsync m => Applicative (ZipAsync m) where
-    pure a = ZipAsync $ scons a Nothing
+    pure = ZipAsync . srepeat
     (<*>) = zipAsyncWith id
 
 instance Streaming ZipAsync where
diff --git a/test/Main.hs b/test/Main.hs
index e740b876..f8dba955 100644
--- a/test/Main.hs
+++ b/test/Main.hs
@@ -422,8 +422,12 @@ zipOps z zM app = do
     it "Applicative zip" $
         let s1 = adapt $ serially $ foldMapWith (<>) return [1..10]
             s2 = adapt $ serially $ foldMapWith (<>) return [1..]
-         in (A.toList . app) ((+) <$> s1 <*> s2)
-        `shouldReturn` ([2,4..20] :: [Int])
+            f = A.toList . app
+            functorial = f $ (+) <$> s1 <*> s2
+            applicative = f $ pure (+) <*> s1 <*> s2
+            expected = ([2,4..20] :: [Int])
+         in (,) <$> functorial <*> applicative
+        `shouldReturn` (expected, expected)
 
 timed :: Int -> StreamT IO Int
 timed x = liftIO (threadDelay (x * 100000)) >> return x

From 20b2d97bc78f953127432151110d7c748b9ba182 Mon Sep 17 00:00:00 2001
From: Hussein Ait Lahcen <hussein.aitlahcen@gmail.com>
Date: Thu, 22 Mar 2018 18:31:08 +0100
Subject: [PATCH 2/2] add: 'Unreleased' changelog section

docs: typo
---
 Changelog.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Changelog.md b/Changelog.md
index b8c9865a..d2e3d510 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,3 +1,8 @@
+## Unreleased
+
+### Bug Fixes
+* Fix Zip/AsyncZip applicative instances to handle applicative injection of function like `pure f <*> s1 <*> s2`
+
 ## 0.1.1
 
 ### Enhancements