Use explicit deriving strategies

effectful-core/effectful-core.cabal

@@ -29,7 +29,10 @@ source-repository head
   location: https://github.com/haskell-effectful/effectful.git
 
 common language
-    ghc-options:        -Wall -Wcompat -Wno-unticked-promoted-constructors
+    ghc-options:        -Wall
+                        -Wcompat
+                        -Wno-unticked-promoted-constructors
+                        -Wmissing-deriving-strategies
                         -Werror=prepositive-qualified-module
 
     default-language:   Haskell2010

effectful-core/src/Effectful/Error/Static.hs

@@ -238,7 +238,7 @@ tryError m = (Right <$> m) `catchError` \es e -> pure $ Left (es, e)
 -- Helpers
 
 newtype ErrorId = ErrorId Unique
-  deriving Eq
+  deriving newtype Eq
 
 -- | A unique is picked so that distinct 'Error' handlers for the same type
 -- don't catch each other's exceptions.

effectful-core/src/Effectful/Internal/Monad.hs

@@ -119,7 +119,7 @@ type role Eff nominal representational
 --
 -- - Allows the effects to be handled in any order.
 newtype Eff (es :: [Effect]) a = Eff (Env es -> IO a)
-  deriving (Monoid, Semigroup)
+  deriving newtype (Monoid, Semigroup)
 
 -- | Run a pure 'Eff' computation.
 --

effectful-core/src/Effectful/Internal/Unlift.hs

@@ -96,7 +96,7 @@ data UnliftStrategy
   -- ^ The concurrent strategy makes it possible for the unlifting function to
   -- be called in threads distinct from its creator. See 'Persistence' and
   -- 'Limit' settings for more information.
-  deriving (Eq, Generic, Ord, Show)
+  deriving stock (Eq, Generic, Ord, Show)
 
 -- | Persistence setting for the 'ConcUnlift' strategy.
 --
@@ -116,7 +116,7 @@ data Persistence
   | Persistent
   -- ^ Persist the environment between calls to the unlifting function within a
   -- particular thread.
-  deriving (Eq, Generic, Ord, Show)
+  deriving stock (Eq, Generic, Ord, Show)
 
 -- | Limit setting for the 'ConcUnlift' strategy.
 data Limit
@@ -135,7 +135,7 @@ data Limit
   -- when called in @N@ threads and @K+1@ copies when called in @K < N@ threads.
   | Unlimited
   -- ^ Unlimited use of the unlifting function.
-  deriving (Eq, Generic, Ord, Show)
+  deriving stock (Eq, Generic, Ord, Show)
 
 ----------------------------------------
 -- Unlift functions
@@ -229,7 +229,7 @@ persistentConcUnlift es0 cleanUp threads k = do
 -- Data types
 
 newtype EntryId = EntryId Int
-  deriving Eq
+  deriving newtype Eq
 
 newEntryId :: EntryId
 newEntryId = EntryId 0

effectful-core/src/Effectful/NonDet.hs

@@ -47,7 +47,7 @@ data OnEmptyPolicy
   --
   -- /Note:/ state modifications are rolled back on 'Empty' only. In particular,
   -- they are __not__ rolled back on exceptions.
-  deriving (Eq, Generic, Ord, Show)
+  deriving stock (Eq, Generic, Ord, Show)
 
 -- | Run the 'NonDet' effect with a given 'OnEmptyPolicy'.
 --

effectful-plugin/effectful-plugin.cabal

@@ -25,7 +25,10 @@ source-repository head
   location: https://github.com/haskell-effectful/effectful.git
 
 common language
-    ghc-options:        -Wall -Wcompat -Wno-unticked-promoted-constructors
+    ghc-options:        -Wall
+                        -Wcompat
+                        -Wno-unticked-promoted-constructors
+                        -Wmissing-deriving-strategies
                         -Werror=prepositive-qualified-module
 
     default-language:   Haskell2010

effectful-plugin/tests/PluginTests.hs

@@ -72,7 +72,7 @@ errState = do
   err
 
 newtype MyString = MyString String
-  deriving (IsString, Eq, Show)
+  deriving newtype (IsString, Eq, Show)
 
 data Janky = forall s. Janky (forall _i. Eff '[State s] ())
 

effectful-th/effectful-th.cabal

@@ -25,7 +25,10 @@ source-repository head
   location: https://github.com/haskell-effectful/effectful.git
 
 common language
-    ghc-options:        -Wall -Wcompat -Wno-unticked-promoted-constructors
+    ghc-options:        -Wall
+                        -Wcompat
+                        -Wno-unticked-promoted-constructors
+                        -Wmissing-deriving-strategies
                         -Werror=prepositive-qualified-module
 
     default-language:   Haskell2010

effectful/bench/FileSizes.hs

@@ -363,7 +363,7 @@ fe_tryFileSize :: FE.Has FE_File sig m => FilePath -> m (Maybe Int)
 fe_tryFileSize = FE.send . FE_tryFileSize
 
 newtype FE_FileC m a = FE_FileC { fe_runFileC :: m a }
-  deriving (Applicative, Functor, Monad, MonadIO)
+  deriving newtype (Applicative, Functor, Monad, MonadIO)
 
 instance
   ( MonadIO m
@@ -380,7 +380,7 @@ fe_logMsg :: FE.Has FE_Logging sig m => String -> m ()
 fe_logMsg = FE.send . FE_logMsg . T.pack
 
 newtype FE_LoggingC m a = FE_LoggingC { fe_runLoggingC :: FE.StateC [Text] m a }
-  deriving (Applicative, Functor, Monad)
+  deriving newtype (Applicative, Functor, Monad)
 
 instance
   ( FE.Algebra sig m
@@ -440,7 +440,7 @@ class Monad m => MonadFile m where
   mtl_tryFileSize :: FilePath -> m (Maybe Int)
 
 newtype FileT m a = FileT { runFileT :: m a }
-  deriving (Functor, Applicative, Monad, MonadIO)
+  deriving newtype (Functor, Applicative, Monad, MonadIO)
 
 instance M.MonadTrans FileT where
   lift = FileT
@@ -459,7 +459,7 @@ class Monad m => MonadLog m where
   mtl_logMsg :: String -> m ()
 
 newtype LoggingT m a = LoggingT (M.StateT [Text] m a)
-  deriving (Functor, Applicative, Monad, MonadIO, M.MonadTrans)
+  deriving newtype (Functor, Applicative, Monad, MonadIO, M.MonadTrans)
 
 instance {-# OVERLAPPABLE #-}
   ( MonadLog m

effectful/effectful.cabal

@@ -34,7 +34,10 @@ flag benchmark-foreign-libraries
     default: False
 
 common language
-    ghc-options:        -Wall -Wcompat -Wno-unticked-promoted-constructors
+    ghc-options:        -Wall
+                        -Wcompat
+                        -Wno-unticked-promoted-constructors
+                        -Wmissing-deriving-strategies
                         -Werror=prepositive-qualified-module
 
     default-language:   Haskell2010

effectful/src/Effectful/Concurrent/Async.hs

@@ -474,7 +474,7 @@ data Conc :: [Effect] -> Type -> Type where
   Alt    :: Conc es a -> Conc es a -> Conc es a
   Empty  :: Conc es a
 
-deriving instance Functor (Conc es)
+deriving stock instance Functor (Conc es)
 
 instance Applicative (Conc es) where
   pure   = Pure

effectful/tests/Utils.hs

@@ -43,5 +43,6 @@ assertThrowsErrorCall
   => String -> Eff es a -> Eff es ()
 assertThrowsErrorCall err = assertThrows err (\ErrorCall{} -> True)
 
-data Ex = Ex deriving (Eq, Show)
+data Ex = Ex
+  deriving stock (Eq, Show)
 instance Exception Ex