9 files changed, 15 insertions, 28 deletions
diff --git a/libraries/base/Data/Complex.hs b/libraries/base/Data/Complex.hs
index 09314f163e..31550d5ac7 100644
--- a/libraries/base/Data/Complex.hs
+++ b/libraries/base/Data/Complex.hs
@@ -213,5 +213,4 @@ instance Applicative Complex where
   f :+ g <*> a :+ b = f a :+ g b
 
 instance Monad Complex where
-  return a = a :+ a
   a :+ b >>= f = realPart (f a) :+ imagPart (f b)
diff --git a/libraries/base/Data/Either.hs b/libraries/base/Data/Either.hs
index d727e5219d..50e95824c8 100644
--- a/libraries/base/Data/Either.hs
+++ b/libraries/base/Data/Either.hs
@@ -134,7 +134,6 @@ instance Applicative (Either e) where
     Right f <*> r = fmap f r
 
 instance Monad (Either e) where
-    return = Right
     Left  l >>= _ = Left l
     Right r >>= k = k r
 
diff --git a/libraries/base/Data/Functor/Identity.hs b/libraries/base/Data/Functor/Identity.hs
index 9f7ae24e66..46fb66650c 100644
--- a/libraries/base/Data/Functor/Identity.hs
+++ b/libraries/base/Data/Functor/Identity.hs
@@ -88,7 +88,6 @@ instance Applicative Identity where
     (<*>)    = coerce
 
 instance Monad Identity where
-    return   = Identity
     m >>= k  = k (runIdentity m)
 
 instance MonadFix Identity where
diff --git a/libraries/base/Data/List/NonEmpty.hs b/libraries/base/Data/List/NonEmpty.hs
index 6698a0ba58..d8bad07c7b 100644
--- a/libraries/base/Data/List/NonEmpty.hs
+++ b/libraries/base/Data/List/NonEmpty.hs
@@ -189,7 +189,6 @@ instance Applicative NonEmpty where
   (<*>) = ap
 
 instance Monad NonEmpty where
-  return a = a :| []
   ~(a :| as) >>= f = b :| (bs ++ bs')
     where b :| bs = f a
           bs' = as >>= toList . f
diff --git a/libraries/base/Data/Monoid.hs b/libraries/base/Data/Monoid.hs
index c5a4d8bdf9..eff3836396 100644
--- a/libraries/base/Data/Monoid.hs
+++ b/libraries/base/Data/Monoid.hs
@@ -82,7 +82,6 @@ instance Applicative Dual where
     (<*>)    = coerce
 
 instance Monad Dual where
-    return   = Dual
     m >>= k  = k (getDual m)
 
 -- | The monoid of endomorphisms under composition.
@@ -126,7 +125,6 @@ instance Applicative Sum where
     (<*>)    = coerce
 
 instance Monad Sum where
-    return   = Sum
     m >>= k  = k (getSum m)
 
 -- | Monoid under multiplication.
@@ -146,7 +144,6 @@ instance Applicative Product where
     (<*>)    = coerce
 
 instance Monad Product where
-    return   = Product
     m >>= k  = k (getProduct m)
 
 -- $MaybeExamples
diff --git a/libraries/base/Data/Proxy.hs b/libraries/base/Data/Proxy.hs
index a9146214c0..2dad8e4e78 100644
--- a/libraries/base/Data/Proxy.hs
+++ b/libraries/base/Data/Proxy.hs
@@ -90,8 +90,6 @@ instance Applicative Proxy where
     {-# INLINE (<*>) #-}
 
 instance Monad Proxy where
-    return _ = Proxy
-    {-# INLINE return #-}
     _ >>= _ = Proxy
     {-# INLINE (>>=) #-}
 
diff --git a/libraries/base/Data/Semigroup.hs b/libraries/base/Data/Semigroup.hs
index 661e513cba..f3f9f0b326 100644
--- a/libraries/base/Data/Semigroup.hs
+++ b/libraries/base/Data/Semigroup.hs
@@ -332,8 +332,7 @@ instance Applicative Min where
   Min f <*> Min x = Min (f x)
 
 instance Monad Min where
-  return = Min
-  _ >> a = a
+  (>>) = (*>)
   Min a >>= f = f a
 
 instance MonadFix Min where
@@ -389,8 +388,7 @@ instance Applicative Max where
   Max f <*> Max x = Max (f x)
 
 instance Monad Max where
-  return = Max
-  _ >> a = a
+  (>>) = (*>)
   Max a >>= f = f a
 
 instance MonadFix Max where
@@ -476,8 +474,7 @@ instance Applicative First where
   First f <*> First x = First (f x)
 
 instance Monad First where
-  return = First
-  _ >> a = a
+  (>>) = (*>)
   First a >>= f = f a
 
 instance MonadFix First where
@@ -523,8 +520,7 @@ instance Applicative Last where
   Last f <*> Last x = Last (f x)
 
 instance Monad Last where
-  return = Last
-  _ >> a = a
+  (>>) = (*>)
   Last a >>= f = f a
 
 instance MonadFix Last where
@@ -584,14 +580,13 @@ instance Applicative Option where
   pure a = Option (Just a)
   Option a <*> Option b = Option (a <*> b)
 
-instance Monad Option where
-  return = pure
+  Option Nothing  *>  _ = Option Nothing
+  _               *>  b = b
 
+instance Monad Option where
   Option (Just a) >>= k = k a
   _               >>= _ = Option Nothing
-
-  Option Nothing  >>  _ = Option Nothing
-  _               >>  b = b
+  (>>) = (*>)
 
 instance Alternative Option where
   empty = Option Nothing
diff --git a/libraries/base/Data/Traversable.hs b/libraries/base/Data/Traversable.hs
index 81e639cf37..9da76c6a34 100644
--- a/libraries/base/Data/Traversable.hs
+++ b/libraries/base/Data/Traversable.hs
@@ -196,9 +196,9 @@ instance Traversable Proxy where
     {-# INLINE traverse #-}
     sequenceA _ = pure Proxy
     {-# INLINE sequenceA #-}
-    mapM _ _ = return Proxy
+    mapM _ _ = pure Proxy
     {-# INLINE mapM #-}
-    sequence _ = return Proxy
+    sequence _ = pure Proxy
     {-# INLINE sequence #-}
 
 instance Traversable (Const m) where
diff --git a/libraries/base/Data/Version.hs b/libraries/base/Data/Version.hs
index aba8cf7f74..414b2aa859 100644
--- a/libraries/base/Data/Version.hs
+++ b/libraries/base/Data/Version.hs
@@ -36,7 +36,8 @@ module Data.Version (
         makeVersion
   ) where
 
-import Control.Monad    ( Monad(..), liftM )
+import Data.Functor     ( Functor(..) )
+import Control.Applicative ( Applicative(..) )
 import Data.Bool        ( (&&) )
 import Data.Char        ( isDigit, isAlphaNum )
 import Data.Eq
@@ -120,9 +121,9 @@ showVersion (Version branch tags)
 -- | A parser for versions in the format produced by 'showVersion'.
 --
 parseVersion :: ReadP Version
-parseVersion = do branch <- sepBy1 (liftM read (munch1 isDigit)) (char '.')
-                  tags   <- many (char '-' >> munch1 isAlphaNum)
-                  return Version{versionBranch=branch, versionTags=tags}
+parseVersion = do branch <- sepBy1 (fmap read (munch1 isDigit)) (char '.')
+                  tags   <- many (char '-' *> munch1 isAlphaNum)
+                  pure Version{versionBranch=branch, versionTags=tags}
 
 -- | Construct tag-less 'Version'
 --