More testsuite thingswip/final-mfp

23 files changed, 34 insertions, 296 deletions

diff --git a/testsuite/tests/deSugar/should_run/dsrun010.hs b/testsuite/tests/deSugar/should_run/dsrun010.hs
index 1d4fc485e0..c11fa2a765 100644
--- a/testsuite/tests/deSugar/should_run/dsrun010.hs
+++ b/testsuite/tests/deSugar/should_run/dsrun010.hs
@@ -2,13 +2,11 @@
 -- is reflected by calling the monadic 'fail', not by a
 -- runtime exception
 
-{-# LANGUAGE NoMonadFailDesugaring #-}
-{-# OPTIONS -Wno-missing-monadfail-instances #-}
-
 import Control.Monad
+import Control.Monad.Fail
 import Data.Maybe
 
-test :: (MonadPlus m) => [a] -> m Bool
+test :: (MonadPlus m, MonadFail m) => [a] -> m Bool
 test xs
   =   do
         (_:_) <- return xs
diff --git a/testsuite/tests/determinism/determ017/A.hs b/testsuite/tests/determinism/determ017/A.hs
index 5e3c3d0809..082c9380de 100644
--- a/testsuite/tests/determinism/determ017/A.hs
+++ b/testsuite/tests/determinism/determ017/A.hs
@@ -20,7 +20,7 @@
 -- | Module "Trampoline" defines the pipe computations and their basic building blocks.
 
 {-# LANGUAGE ScopedTypeVariables, Rank2Types, MultiParamTypeClasses,
-             TypeFamilies, KindSignatures, FlexibleContexts, NoMonadFailDesugaring,
+             TypeFamilies, KindSignatures, FlexibleContexts,
              FlexibleInstances, OverlappingInstances, UndecidableInstances
  #-}
 
@@ -81,6 +81,9 @@ instance Monad Identity where
     return a = Identity a
     m >>= k  = k (runIdentity m)
 
+instance MonadFail Identity where
+    fail = error "Identity(fail)"
+
 newtype Trampoline m s r = Trampoline {bounce :: m (TrampolineState m s r)}
 data TrampolineState m s r = Done r | Suspend! (s (Trampoline m s r))
 
@@ -97,6 +100,9 @@ instance (Monad m, Functor s) => Monad (Trampoline m s) where
       where apply f (Done x) = bounce (f x)
             apply f (Suspend s) = return (Suspend (fmap (>>= f) s))
 
+instance (MonadFail m, Functor s) => MonadFail (Trampoline m s) where
+   fail = error "Trampoline(fail)"
+
 data Yield x y = Yield! x y
 instance Functor (Yield x) where
    fmap f (Yield x y) = trace "fmap yield" $ Yield x (f y)
diff --git a/testsuite/tests/monadfail/MonadFailWarningsDisabled.hs b/testsuite/tests/monadfail/MonadFailWarningsDisabled.hs
deleted file mode 100644
index 858a212b45..0000000000
--- a/testsuite/tests/monadfail/MonadFailWarningsDisabled.hs
+++ /dev/null
@@ -1,100 +0,0 @@
--- Test purpose:
--- Make sure that not enabling MonadFail warnings makes code compile just
--- as it did in < 8.0
-
--- NOTE: starting w/ GHC 8.6 sugaring is turned on by default; so we have
---       to disable to keep supporting this test-case
---
-{-# LANGUAGE NoMonadFailDesugaring #-}
-{-# OPTIONS -Wno-missing-monadfail-instances #-}
-
-module MonadFailWarnings where
-
-import Control.Monad.Fail
-import Control.Monad.ST
-import Data.Functor.Identity
-
-
-
-general :: Monad m => m a
-general = do
-    Just x <- undefined
-    undefined
-
-
-
-general' :: MonadFail m => m a
-general' = do
-    Just x <- undefined
-    undefined
-
-
-
-identity :: Identity a
-identity = do
-    Just x <- undefined
-    undefined
-
-
-
-io :: IO a
-io = do
-    Just x <- undefined
-    undefined
-
-
-
-st :: ST s a
-st = do
-    Just x <- undefined
-    undefined
-
-
-
-reader :: r -> a
-reader = do
-    Just x <- undefined
-    undefined
-
-
-
-newtype Newtype a = Newtype a
-newtypeMatch :: Identity a
-newtypeMatch = do
-    Newtype x <- undefined
-    undefined
-
-
-
-data Data a = Data a
-singleConMatch :: Identity a
-singleConMatch = do
-    Data x <- undefined
-    undefined
-
-
-
-data Maybe' a = Nothing' | Just' a
-instance Functor Maybe' where fmap = undefined
-instance Applicative Maybe' where pure = undefined; (<*>) = undefined
-instance Monad Maybe' where (>>=) = undefined
-instance MonadFail Maybe' where fail = undefined
-customFailable :: Maybe' a
-customFailable = do
-    Just x <- undefined
-    undefined
-
-
-wildcardx, explicitlyIrrefutable, wildcard_, tuple :: Monad m => m a
-wildcardx = do
-    x <- undefined
-    undefined
-explicitlyIrrefutable = do
-    ~(x:y) <- undefined
-    undefined
-wildcard_ = do
-    _ <- undefined
-    undefined
-tuple = do
-    (a,b) <- undefined
-    undefined
diff --git a/testsuite/tests/monadfail/all.T b/testsuite/tests/monadfail/all.T
index 32eddb9e98..c718e91eef 100644
--- a/testsuite/tests/monadfail/all.T
+++ b/testsuite/tests/monadfail/all.T
@@ -1,4 +1,3 @@
 test('MonadFailWarnings', normal, compile, [''])
 test('MonadFailErrors', normal, compile_fail, [''])
-test('MonadFailWarningsDisabled', normal, compile, [''])
 test('MonadFailWarningsWithRebindableSyntax', normal, compile, [''])
diff --git a/testsuite/tests/perf/compiler/T3064.hs b/testsuite/tests/perf/compiler/T3064.hs
index dacca79296..e29dd95564 100644
--- a/testsuite/tests/perf/compiler/T3064.hs
+++ b/testsuite/tests/perf/compiler/T3064.hs
@@ -19,6 +19,8 @@ instance (Monad m) => Monad (ReaderT r m) where
     m >>= k  = ReaderT $ \r -> do
         a <- runReaderT m r
         runReaderT (k a) r
+
+instance (MonadFail m) => MonadFail (ReaderT r m) where
     fail msg = ReaderT $ \_ -> fail msg
 
 newtype ResourceT r s m v = ResourceT { unResourceT :: ReaderT r m v }
diff --git a/testsuite/tests/programs/galois_raytrace/Eval.hs b/testsuite/tests/programs/galois_raytrace/Eval.hs
index 001842edad..250c4c4afb 100644
--- a/testsuite/tests/programs/galois_raytrace/Eval.hs
+++ b/testsuite/tests/programs/galois_raytrace/Eval.hs
@@ -33,7 +33,6 @@ instance Applicative Pure where
 instance Monad Pure where
     Pure x >>= k = k x
     return       = pure
-    fail s       = error s
 
 instance MonadEval Pure where
   doOp   = doPureOp
@@ -306,6 +305,8 @@ instance Monad Abs where
                                    AbsState r s' -> runAbs (k r) s'
                                    AbsFail m     -> AbsFail m)
     return       = pure
+
+instance MonadFail Abs where
     fail s       = Abs (\ n -> AbsFail s)
 
 instance MonadEval Abs where
diff --git a/testsuite/tests/quasiquotation/qq005/Expr.hs b/testsuite/tests/quasiquotation/qq005/Expr.hs
index 1c51d9db1f..767d906ba4 100644
--- a/testsuite/tests/quasiquotation/qq005/Expr.hs
+++ b/testsuite/tests/quasiquotation/qq005/Expr.hs
@@ -64,7 +64,7 @@ anti   = lexeme $
              cs <- many idchar
              return $ AntiIntExpr (c : cs)
 
-parseExpr :: Monad m => TH.Loc -> String -> m Expr
+parseExpr :: MonadFail m => TH.Loc -> String -> m Expr
 parseExpr (Loc {loc_filename = file, loc_start = (line,col)}) s =
     case runParser p () "" s of
       Left err  -> fail $ show err
diff --git a/testsuite/tests/quasiquotation/qq006/Expr.hs b/testsuite/tests/quasiquotation/qq006/Expr.hs
index 1c51d9db1f..767d906ba4 100644
--- a/testsuite/tests/quasiquotation/qq006/Expr.hs
+++ b/testsuite/tests/quasiquotation/qq006/Expr.hs
@@ -64,7 +64,7 @@ anti   = lexeme $
              cs <- many idchar
              return $ AntiIntExpr (c : cs)
 
-parseExpr :: Monad m => TH.Loc -> String -> m Expr
+parseExpr :: MonadFail m => TH.Loc -> String -> m Expr
 parseExpr (Loc {loc_filename = file, loc_start = (line,col)}) s =
     case runParser p () "" s of
       Left err  -> fail $ show err
diff --git a/testsuite/tests/rebindable/DoRestrictedM.hs b/testsuite/tests/rebindable/DoRestrictedM.hs
index 4f7885783e..de28079769 100644
--- a/testsuite/tests/rebindable/DoRestrictedM.hs
+++ b/testsuite/tests/rebindable/DoRestrictedM.hs
@@ -30,10 +30,11 @@ m1 >> m2 = m1 >>= (const m2)
 
 newtype RegularM m a = RegularM{unRM :: m a}
 
-instance Prelude.Monad m => MN2 (RegularM m) a where
+instance Prelude.MonadFail m => MN2 (RegularM m) a where
     return = RegularM . Prelude.return
+    fail = fail
 
-instance Prelude.Monad m => MN3 (RegularM m) a b where
+instance Prelude.MonadFail m => MN3 (RegularM m) a b where
     m >>= f = RegularM ((Prelude.>>=) (unRM m) (unRM . f))
 
 -- We try to inject Maybe (as the regular monad) into Restricted Monad
diff --git a/testsuite/tests/rebindable/rebindable2.hs b/testsuite/tests/rebindable/rebindable2.hs
index 9fe15150f4..3858d2b9f3 100644
--- a/testsuite/tests/rebindable/rebindable2.hs
+++ b/testsuite/tests/rebindable/rebindable2.hs
@@ -8,7 +8,7 @@ module Main where
         import Prelude(String,undefined,Maybe(..),IO,putStrLn,
                 Integer,(++),Rational, (==), (>=) );
 
-        import Prelude(Monad(..),Applicative(..),Functor(..));
+        import Prelude(Monad(..),Applicative(..),Functor(..),MonadFail(..));
         import Control.Monad(ap, liftM);
 
         debugFunc :: String -> IO a -> IO a;
@@ -35,7 +35,9 @@ module Main where
                 (>>=) ma amb = MkTM (debugFunc ">>=" ((Prelude.>>=) (unTM ma) (\a -> unTM (amb a))));
 
                 (>>) ma mb = MkTM (debugFunc ">>" ((Prelude.>>) (unTM ma) (unTM mb)));
-
+                };
+        instance (MonadFail TM) where
+                {
                 fail s = MkTM (debugFunc "fail" (Prelude.return undefined));
                 };
 
diff --git a/testsuite/tests/simplCore/prog002/Simpl009Help.hs b/testsuite/tests/simplCore/prog002/Simpl009Help.hs
index e4c6df351e..b64639ec8a 100644
--- a/testsuite/tests/simplCore/prog002/Simpl009Help.hs
+++ b/testsuite/tests/simplCore/prog002/Simpl009Help.hs
@@ -28,9 +28,6 @@ instance Monad (Parser s) where
   Parser f >>= k =
     Parser (\fut -> f (\a -> let Parser g = k a in g fut))
 
-  fail s =
-    Parser (\fut exp -> Fail exp [s])
-
 instance Alternative (Parser s) where
     empty = mzero
     (<|>) = mplus
diff --git a/testsuite/tests/simplCore/should_compile/T8331.hs b/testsuite/tests/simplCore/should_compile/T8331.hs
index 04cb1aff73..a7dc318826 100644
--- a/testsuite/tests/simplCore/should_compile/T8331.hs
+++ b/testsuite/tests/simplCore/should_compile/T8331.hs
@@ -23,6 +23,8 @@ instance (Monad m) => Monad (ReaderT r m) where
     m >>= k  = ReaderT $ \ r -> do
         a <- runReaderT m r
         runReaderT (k a) r
+
+instance MonadFail m => MonadFail (ReaderT r m) where
     fail msg = ReaderT (\_ -> fail msg)
 
 mapReaderT :: (m a -> n b) -> ReaderT r m a -> ReaderT r n b
diff --git a/testsuite/tests/typecheck/should_compile/T4524.hs b/testsuite/tests/typecheck/should_compile/T4524.hs
index 669c4b268a..fbdc0cd77c 100644
--- a/testsuite/tests/typecheck/should_compile/T4524.hs
+++ b/testsuite/tests/typecheck/should_compile/T4524.hs
@@ -174,6 +174,8 @@ instance  Monad Perhaps where
     (Succeeded _) >> k  =  k
     Unknown  >> k       =  k
     return              =  Succeeded
+
+instance MonadFail Perhaps where
     fail _              =  Unknown
 
 instance Alternative Perhaps where
diff --git a/testsuite/tests/typecheck/should_compile/T4969.hs b/testsuite/tests/typecheck/should_compile/T4969.hs
index 6a087974c7..b8332bdcba 100644
--- a/testsuite/tests/typecheck/should_compile/T4969.hs
+++ b/testsuite/tests/typecheck/should_compile/T4969.hs
@@ -89,7 +89,6 @@ instance Applicative (TCMT m) where
 instance Monad (TCMT m) where
     return = undefined
     (>>=) = undefined
-    fail = undefined
 
 instance Monad m => MonadIO (TCMT m) where
 
diff --git a/testsuite/tests/typecheck/should_compile/Tc239_Help.hs b/testsuite/tests/typecheck/should_compile/Tc239_Help.hs
index 4f39612e4e..1718c99088 100644
--- a/testsuite/tests/typecheck/should_compile/Tc239_Help.hs
+++ b/testsuite/tests/typecheck/should_compile/Tc239_Help.hs
@@ -20,4 +20,3 @@ instance Monad (WrapIO e) where
   m >>= f  = MkWrapIO (do x <- unwrap m
                           unwrap (f x) )
 
-  fail str = error str
\ No newline at end of file
diff --git a/testsuite/tests/typecheck/should_run/T1735_Help/State.hs b/testsuite/tests/typecheck/should_run/T1735_Help/State.hs
index 44078ae944..093a7e2c81 100644
--- a/testsuite/tests/typecheck/should_run/T1735_Help/State.hs
+++ b/testsuite/tests/typecheck/should_run/T1735_Help/State.hs
@@ -11,7 +11,9 @@ instance Monad m => Monad (StateT s m) where
     m >>= k  = StateT $ \s -> do
         ~(a, s') <- runStateT m s
         runStateT (k a) s'
-    fail str = StateT $ \_ -> fail str
+
+instance MonadFail m => MonadFail (StateT s m) where
+    fail s = StateT $ \_ -> fail s
 
 instance Monad m => Functor (StateT s m) where
     fmap = liftM
diff --git a/testsuite/tests/warnings/should_compile/T11128.hs b/testsuite/tests/warnings/should_compile/T11128.hs
deleted file mode 100644
index 23725c1e4b..0000000000
--- a/testsuite/tests/warnings/should_compile/T11128.hs
+++ /dev/null
@@ -1,50 +0,0 @@
-{-# LANGUAGE DeriveFunctor #-}
-{-# OPTIONS_GHC -fwarn-noncanonical-monad-instances  #-}
-
--- | Test noncanonical-monad-instances warnings
-module T11128 where
-
-import Control.Applicative as A
-import Control.Monad as M
-
-----------------------------------------------------------------------------
--- minimal definition
-
-data T0 a  = T0 a deriving Functor
-
-instance A.Applicative T0 where
-    pure   = T0
-    (<*>)  = M.ap
-
-instance M.Monad T0 where
-    (>>=)  = undefined
-
-----------------------------------------------------------------------------
--- trigger all 4 warnings
-
-data T1 a  = T1 a deriving Functor
-
-instance A.Applicative T1 where
-    pure   = return
-    (<*>)  = M.ap
-    (*>)   = (M.>>)
-
-instance M.Monad T1 where
-    (>>=)  = undefined
-    return = T1
-    (>>)   = undefined
-
-----------------------------------------------------------------------------
--- backward compat canonical definition
-
-data T2 a  = T2 a deriving Functor
-
-instance Applicative T2 where
-    pure   = T2
-    (<*>)  = ap
-    (*>)   = undefined
-
-instance M.Monad T2 where
-    (>>=)  = undefined
-    return = pure
-    (>>)   = (*>)
diff --git a/testsuite/tests/warnings/should_compile/T11128.stderr b/testsuite/tests/warnings/should_compile/T11128.stderr
deleted file mode 100644
index b8d788236c..0000000000
--- a/testsuite/tests/warnings/should_compile/T11128.stderr
+++ /dev/null
@@ -1,20 +0,0 @@
-
-T11128.hs:28:5: warning: [-Wnoncanonical-monad-instances]
-    Noncanonical ‘pure = return’ definition detected
-    in the instance declaration for ‘Applicative T1’.
-    Move definition from ‘return’ to ‘pure’
-
-T11128.hs:30:5: warning: [-Wnoncanonical-monad-instances]
-    Noncanonical ‘(*>) = (>>)’ definition detected
-    in the instance declaration for ‘Applicative T1’.
-    Move definition from ‘(>>)’ to ‘(*>)’
-
-T11128.hs:34:5: warning: [-Wnoncanonical-monad-instances]
-    Noncanonical ‘return’ definition detected
-    in the instance declaration for ‘Monad T1’.
-    Either remove definition for ‘return’ or define as ‘return = pure’
-
-T11128.hs:35:5: warning: [-Wnoncanonical-monad-instances]
-    Noncanonical ‘(>>)’ definition detected
-    in the instance declaration for ‘Monad T1’.
-    Either remove definition for ‘(>>)’ or define as ‘(>>) = (*>)’
diff --git a/testsuite/tests/warnings/should_compile/T11128b.hs b/testsuite/tests/warnings/should_compile/T11128b.hs
deleted file mode 100644
index 497927716c..0000000000
--- a/testsuite/tests/warnings/should_compile/T11128b.hs
+++ /dev/null
@@ -1,64 +0,0 @@
-{-# LANGUAGE DeriveFunctor #-}
-{-# OPTIONS_GHC -Wnoncanonical-monadfail-instances  #-}
-
--- | Test noncanonical-monadfail-instances warnings
-module T11128b where
-
-import Control.Applicative as A
-import Control.Monad as M
-import Control.Monad.Fail as MF
-
-----------------------------------------------------------------------------
--- minimal definition
-
-data T0 a  = T0 a deriving Functor
-
-instance A.Applicative T0 where
-    pure   = T0
-    (<*>)  = M.ap
-
-instance M.Monad T0 where
-    (>>=)  = undefined
-
-instance MF.MonadFail T0 where
-    fail   = error "fail"
-
-----------------------------------------------------------------------------
--- trigger all 2 warnings
-
-data T1 a  = T1 a deriving Functor
-
-instance A.Applicative T1 where
-    pure   = return
-    (<*>)  = M.ap
-    (*>)   = (M.>>)
-
-instance M.Monad T1 where
-    (>>=)  = undefined
-    return = T1
-    (>>)   = undefined
-    fail   = error "fail"
-
-instance MF.MonadFail T1 where
-    fail   = M.fail
-
-----------------------------------------------------------------------------
--- backward compat canonical definition
-
-data T2 a  = T2 a deriving Functor
-
-instance Applicative T2 where
-    pure   = T2
-    (<*>)  = ap
-    (*>)   = undefined
-
-instance M.Monad T2 where
-    (>>=)  = undefined
-    return = pure
-    (>>)   = (*>)
-    fail   = MF.fail
-
-instance MF.MonadFail T2 where
-    fail   = error "fail"
-
-----------------------------------------------------------------------------
diff --git a/testsuite/tests/warnings/should_compile/T11128b.stderr b/testsuite/tests/warnings/should_compile/T11128b.stderr
deleted file mode 100644
index e3fd3e83dc..0000000000
--- a/testsuite/tests/warnings/should_compile/T11128b.stderr
+++ /dev/null
@@ -1,10 +0,0 @@
-
-T11128b.hs:40:5: warning: [-Wnoncanonical-monadfail-instances]
-    Noncanonical ‘fail’ definition detected
-    in the instance declaration for ‘Monad T1’.
-    Either remove definition for ‘fail’ or define as ‘fail = Control.Monad.Fail.fail’
-
-T11128b.hs:43:5: warning: [-Wnoncanonical-monadfail-instances]
-    Noncanonical ‘fail = Control.Monad.fail’ definition detected
-    in the instance declaration for ‘MonadFail T1’.
-    Move definition from ‘Control.Monad.fail’ to ‘fail’
diff --git a/testsuite/tests/warnings/should_compile/all.T b/testsuite/tests/warnings/should_compile/all.T
index 10a3ecf12c..36e6b1beeb 100644
--- a/testsuite/tests/warnings/should_compile/all.T
+++ b/testsuite/tests/warnings/should_compile/all.T
@@ -9,8 +9,6 @@ test('T10908', normal, compile, [''])
 test('T10930', normal, compile, [''])
 test('T10930b', normal, compile, [''])
 test('T11077', normal, compile, ['-fwarn-missing-exported-signatures'])
-test('T11128', normal, compile, [''])
-test('T11128b', normal, compile, [''])
 test('T13256', normal, compile, [''])
 test('T15460', normal, compile, [''])
 test('PluralS', normal, compile, [''])
diff --git a/testsuite/tests/wcompat-warnings/Template.hs b/testsuite/tests/wcompat-warnings/Template.hs
index 03f9a4957e..798eafc787 100644
--- a/testsuite/tests/wcompat-warnings/Template.hs
+++ b/testsuite/tests/wcompat-warnings/Template.hs
@@ -1,14 +1,9 @@
-{-# LANGUAGE NoMonadFailDesugaring, KindSignatures #-}
+{-# LANGUAGE KindSignatures #-}
 
 module WCompatWarningsOnOff where
 
 import qualified Data.Semigroup as Semi
 
-monadFail :: Monad m => m a
-monadFail = do
-    Just _ <- undefined
-    undefined
-
 (<>) = undefined -- Semigroup warnings
 
 -- -fwarn-noncanonical-monoid-instances
diff --git a/testsuite/tests/wcompat-warnings/WCompatWarningsOn.stderr b/testsuite/tests/wcompat-warnings/WCompatWarningsOn.stderr
index 3c3e73ddf6..b0d7bb2636 100644
--- a/testsuite/tests/wcompat-warnings/WCompatWarningsOn.stderr
+++ b/testsuite/tests/wcompat-warnings/WCompatWarningsOn.stderr
@@ -1,40 +1,19 @@
 
-Template.hs:9:5: warning: [-Wmissing-monadfail-instances (in -Wcompat)]
-    • Could not deduce (Control.Monad.Fail.MonadFail m)
-        arising from the failable pattern ‘Just _’
-        (this will become an error in a future GHC release)
-      from the context: Monad m
-        bound by the type signature for:
-                   monadFail :: forall (m :: * -> *) a. Monad m => m a
-        at Template.hs:7:1-27
-      Possible fix:
-        add (Control.Monad.Fail.MonadFail m) to the context of
-          the type signature for:
-            monadFail :: forall (m :: * -> *) a. Monad m => m a
-    • In a stmt of a 'do' block: Just _ <- undefined
-      In the expression:
-        do Just _ <- undefined
-           undefined
-      In an equation for ‘monadFail’:
-          monadFail
-            = do Just _ <- undefined
-                 undefined
-
-Template.hs:12:1: warning: [-Wsemigroup (in -Wcompat)]
+Template.hs:7:1: warning: [-Wsemigroup (in -Wcompat)]
     Local definition of ‘<>’ clashes with a future Prelude name.
     This will become an error in a future release.
 
-Template.hs:18:3: warning: [-Wnoncanonical-monoid-instances (in -Wcompat)]
+Template.hs:13:3: warning: [-Wnoncanonical-monoid-instances (in -Wcompat)]
     Noncanonical ‘(<>) = mappend’ definition detected
     in the instance declaration for ‘Semigroup S’.
     Move definition from ‘mappend’ to ‘(<>)’
 
-Template.hs:21:3: warning: [-Wnoncanonical-monoid-instances (in -Wcompat)]
+Template.hs:16:3: warning: [-Wnoncanonical-monoid-instances (in -Wcompat)]
     Noncanonical ‘mappend’ definition detected
     in the instance declaration for ‘Monoid S’.
     Define as ‘mappend = (<>)’
 
-Template.hs:25:15: warning: [-Wstar-is-type (in -Wcompat)]
+Template.hs:20:15: warning: [-Wstar-is-type (in -Wcompat)]
     Using ‘*’ (or its Unicode variant) to mean ‘Data.Kind.Type’
     relies on the StarIsType extension, which will become
     deprecated in the future.