base: Remove `Monad(fail)` method and reexport `MonadFail(fail)` instead

As per https://prime.haskell.org/wiki/Libraries/Proposals/MonadFail

Coauthored-by: Ben Gamari <ben@well-typed.com>

14 files changed, 18 insertions, 40 deletions

diff --git a/testsuite/tests/typecheck/should_compile/T12763.stderr b/testsuite/tests/typecheck/should_compile/T12763.stderr
index eff7c0a28f..d5abb6c6af 100644
--- a/testsuite/tests/typecheck/should_compile/T12763.stderr
+++ b/testsuite/tests/typecheck/should_compile/T12763.stderr
@@ -8,5 +8,5 @@ COERCION AXIOMS
 CLASS INSTANCES
   instance C Int -- Defined at T12763.hs:9:10
 Dependent modules: []
-Dependent packages: [base-4.12.0.0, ghc-prim-0.5.3,
+Dependent packages: [base-4.13.0.0, ghc-prim-0.5.3,
                      integer-gmp-1.0.2.0]
diff --git a/testsuite/tests/typecheck/should_compile/T15645.stderr b/testsuite/tests/typecheck/should_compile/T15645.stderr
deleted file mode 100644
index 566d6bf18e..0000000000
--- a/testsuite/tests/typecheck/should_compile/T15645.stderr
+++ /dev/null
@@ -1,4 +0,0 @@
-T15645.hs:8:5: warning: [-Wmissing-monadfail-instances (in -Wcompat)]
-    The failable pattern ‘Just y’
-      is used together with -XRebindableSyntax. If this is intentional,
-      compile with -Wno-missing-monadfail-instances.
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_compile/abstract_refinement_hole_fits.stderr b/testsuite/tests/typecheck/should_compile/abstract_refinement_hole_fits.stderr
index d3ea7d4533..227df63ecc 100644
--- a/testsuite/tests/typecheck/should_compile/abstract_refinement_hole_fits.stderr
+++ b/testsuite/tests/typecheck/should_compile/abstract_refinement_hole_fits.stderr
@@ -36,8 +36,6 @@ abstract_refinement_hole_fits.hs:4:5: warning: [-Wtyped-holes (in -Wdefault)]
           where const :: forall a b. a -> b -> a
         ($) (_ :: [Integer] -> Integer)
           where ($) :: forall a b. (a -> b) -> a -> b
-        fail (_ :: [Char])
-          where fail :: forall (m :: * -> *) a. Monad m => String -> m a
         return (_ :: Integer)
           where return :: forall (m :: * -> *) a. Monad m => a -> m a
         pure (_ :: Integer)
@@ -116,8 +114,6 @@ abstract_refinement_hole_fits.hs:4:5: warning: [-Wtyped-holes (in -Wdefault)]
           where const :: forall a b. a -> b -> a
         ($) (_ :: a5 -> [Integer] -> Integer) (_ :: a5)
           where ($) :: forall a b. (a -> b) -> a -> b
-        fail (_ :: [Char]) (_ :: t1)
-          where fail :: forall (m :: * -> *) a. Monad m => String -> m a
         return (_ :: [Integer] -> Integer) (_ :: t1)
           where return :: forall (m :: * -> *) a. Monad m => a -> m a
         pure (_ :: [Integer] -> Integer) (_ :: t1)
@@ -156,8 +152,6 @@ abstract_refinement_hole_fits.hs:7:5: warning: [-Wtyped-holes (in -Wdefault)]
           where const :: forall a b. a -> b -> a
         ($) (_ :: Integer -> [Integer] -> Integer)
           where ($) :: forall a b. (a -> b) -> a -> b
-        fail (_ :: [Char])
-          where fail :: forall (m :: * -> *) a. Monad m => String -> m a
         return (_ :: [Integer] -> Integer)
           where return :: forall (m :: * -> *) a. Monad m => a -> m a
         pure (_ :: [Integer] -> Integer)
@@ -240,8 +234,6 @@ abstract_refinement_hole_fits.hs:7:5: warning: [-Wtyped-holes (in -Wdefault)]
           where const :: forall a b. a -> b -> a
         ($) (_ :: a5 -> Integer -> [Integer] -> Integer) (_ :: a5)
           where ($) :: forall a b. (a -> b) -> a -> b
-        fail (_ :: [Char]) (_ :: t1)
-          where fail :: forall (m :: * -> *) a. Monad m => String -> m a
         return (_ :: Integer -> [Integer] -> Integer) (_ :: t1)
           where return :: forall (m :: * -> *) a. Monad m => a -> m a
         pure (_ :: Integer -> [Integer] -> Integer) (_ :: t1)
diff --git a/testsuite/tests/typecheck/should_compile/constraint_hole_fits.stderr b/testsuite/tests/typecheck/should_compile/constraint_hole_fits.stderr
index 3ba80087e5..233f8e23d2 100644
--- a/testsuite/tests/typecheck/should_compile/constraint_hole_fits.stderr
+++ b/testsuite/tests/typecheck/should_compile/constraint_hole_fits.stderr
@@ -37,8 +37,6 @@ constraint_hole_fits.hs:4:5: warning: [-Wtyped-holes (in -Wdefault)]
           where const :: forall a b. a -> b -> a
         ($) (_ :: [a] -> a)
           where ($) :: forall a b. (a -> b) -> a -> b
-        fail (_ :: [Char])
-          where fail :: forall (m :: * -> *) a. Monad m => String -> m a
         return (_ :: a)
           where return :: forall (m :: * -> *) a. Monad m => a -> m a
         pure (_ :: a)
diff --git a/testsuite/tests/typecheck/should_compile/refinement_hole_fits.stderr b/testsuite/tests/typecheck/should_compile/refinement_hole_fits.stderr
index 888680d228..51e29fd3a2 100644
--- a/testsuite/tests/typecheck/should_compile/refinement_hole_fits.stderr
+++ b/testsuite/tests/typecheck/should_compile/refinement_hole_fits.stderr
@@ -71,11 +71,6 @@ refinement_hole_fits.hs:4:5: warning: [-Wtyped-holes (in -Wdefault)]
           with ($) @'GHC.Types.LiftedRep @[Integer] @Integer
           (imported from ‘Prelude’ at refinement_hole_fits.hs:1:8-30
            (and originally defined in ‘GHC.Base’))
-        fail (_ :: [Char])
-          where fail :: forall (m :: * -> *) a. Monad m => String -> m a
-          with fail @((->) [Integer]) @Integer
-          (imported from ‘Prelude’ at refinement_hole_fits.hs:1:8-30
-           (and originally defined in ‘GHC.Base’))
         return (_ :: Integer)
           where return :: forall (m :: * -> *) a. Monad m => a -> m a
           with return @((->) [Integer]) @Integer
@@ -172,11 +167,6 @@ refinement_hole_fits.hs:7:5: warning: [-Wtyped-holes (in -Wdefault)]
           with ($) @'GHC.Types.LiftedRep @Integer @([Integer] -> Integer)
           (imported from ‘Prelude’ at refinement_hole_fits.hs:1:8-30
            (and originally defined in ‘GHC.Base’))
-        fail (_ :: [Char])
-          where fail :: forall (m :: * -> *) a. Monad m => String -> m a
-          with fail @((->) Integer) @([Integer] -> Integer)
-          (imported from ‘Prelude’ at refinement_hole_fits.hs:1:8-30
-           (and originally defined in ‘GHC.Base’))
         return (_ :: [Integer] -> Integer)
           where return :: forall (m :: * -> *) a. Monad m => a -> m a
           with return @((->) Integer) @([Integer] -> Integer)
diff --git a/testsuite/tests/typecheck/should_compile/subsumption_sort_hole_fits.stderr b/testsuite/tests/typecheck/should_compile/subsumption_sort_hole_fits.stderr
index 7751113761..0d15bc4d1d 100644
--- a/testsuite/tests/typecheck/should_compile/subsumption_sort_hole_fits.stderr
+++ b/testsuite/tests/typecheck/should_compile/subsumption_sort_hole_fits.stderr
@@ -9,10 +9,10 @@ subsumption_sort_hole_fits.hs:2:5: warning: [-Wtyped-holes (in -Wdefault)]
       Valid hole fits include
         lines :: String -> [String]
           (imported from ‘Prelude’ at subsumption_sort_hole_fits.hs:1:1
-           (and originally defined in ‘base-4.12.0.0:Data.OldList’))
+           (and originally defined in ‘base-4.13.0.0:Data.OldList’))
         words :: String -> [String]
           (imported from ‘Prelude’ at subsumption_sort_hole_fits.hs:1:1
-           (and originally defined in ‘base-4.12.0.0:Data.OldList’))
+           (and originally defined in ‘base-4.13.0.0:Data.OldList’))
         read :: forall a. Read a => String -> a
           with read @[String]
           (imported from ‘Prelude’ at subsumption_sort_hole_fits.hs:1:1
@@ -25,6 +25,10 @@ subsumption_sort_hole_fits.hs:2:5: warning: [-Wtyped-holes (in -Wdefault)]
           with mempty @([Char] -> [String])
           (imported from ‘Prelude’ at subsumption_sort_hole_fits.hs:1:1
            (and originally defined in ‘GHC.Base’))
+        fail :: forall (m :: * -> *) a. MonadFail m => String -> m a
+          with fail @[] @String
+          (imported from ‘Prelude’ at subsumption_sort_hole_fits.hs:1:1
+           (and originally defined in ‘Control.Monad.Fail’))
         return :: forall (m :: * -> *) a. Monad m => a -> m a
           with return @[] @String
           (imported from ‘Prelude’ at subsumption_sort_hole_fits.hs:1:1
@@ -33,7 +37,3 @@ subsumption_sort_hole_fits.hs:2:5: warning: [-Wtyped-holes (in -Wdefault)]
           with pure @[] @String
           (imported from ‘Prelude’ at subsumption_sort_hole_fits.hs:1:1
            (and originally defined in ‘GHC.Base’))
-        fail :: forall (m :: * -> *) a. Monad m => String -> m a
-          with fail @[] @String
-          (imported from ‘Prelude’ at subsumption_sort_hole_fits.hs:1:1
-           (and originally defined in ‘GHC.Base’))
diff --git a/testsuite/tests/typecheck/should_compile/tc231.stderr b/testsuite/tests/typecheck/should_compile/tc231.stderr
index 8340d3f033..ed38d5309a 100644
--- a/testsuite/tests/typecheck/should_compile/tc231.stderr
+++ b/testsuite/tests/typecheck/should_compile/tc231.stderr
@@ -15,5 +15,5 @@ DATA CONSTRUCTORS
   Z :: forall a. a -> Z a
   Node :: forall s a chain. s -> a -> chain -> Q s a chain
 Dependent modules: []
-Dependent packages: [base-4.12.0.0, ghc-prim-0.5.3,
+Dependent packages: [base-4.13.0.0, ghc-prim-0.5.3,
                      integer-gmp-1.0.2.0]
diff --git a/testsuite/tests/typecheck/should_compile/valid_hole_fits.stderr b/testsuite/tests/typecheck/should_compile/valid_hole_fits.stderr
index c9d6f44e20..355bfe959c 100644
--- a/testsuite/tests/typecheck/should_compile/valid_hole_fits.stderr
+++ b/testsuite/tests/typecheck/should_compile/valid_hole_fits.stderr
@@ -244,10 +244,10 @@ valid_hole_fits.hs:41:8: warning: [-Wtyped-holes (in -Wdefault)]
           with print @[Char]
           (imported from ‘Prelude’ at valid_hole_fits.hs:3:1-40
            (and originally defined in ‘System.IO’))
-        fail :: forall (m :: * -> *) a. Monad m => String -> m a
+        fail :: forall (m :: * -> *) a. MonadFail m => String -> m a
           with fail @IO @()
           (imported from ‘Prelude’ at valid_hole_fits.hs:3:1-40
-           (and originally defined in ‘GHC.Base’))
+           (and originally defined in ‘Control.Monad.Fail’))
         mempty :: forall a. Monoid a => a
           with mempty @([Char] -> IO ())
           (imported from ‘Prelude’ at valid_hole_fits.hs:3:1-40
diff --git a/testsuite/tests/typecheck/should_fail/TcStaticPointersFail02.stderr b/testsuite/tests/typecheck/should_fail/TcStaticPointersFail02.stderr
index c4d811c567..ef6e0def11 100644
--- a/testsuite/tests/typecheck/should_fail/TcStaticPointersFail02.stderr
+++ b/testsuite/tests/typecheck/should_fail/TcStaticPointersFail02.stderr
@@ -1,13 +1,13 @@
 
 TcStaticPointersFail02.hs:9:6: error:
-    • No instance for (base-4.12.0.0:Data.Typeable.Internal.Typeable b)
+    • No instance for (base-4.13.0.0:Data.Typeable.Internal.Typeable b)
         arising from a static form
     • In the expression: static (undefined :: (forall a. a -> a) -> b)
       In an equation for ‘f1’:
           f1 = static (undefined :: (forall a. a -> a) -> b)
 
 TcStaticPointersFail02.hs:12:6: error:
-    • No instance for (base-4.12.0.0:Data.Typeable.Internal.Typeable
+    • No instance for (base-4.13.0.0:Data.Typeable.Internal.Typeable
                          (Monad m => a -> m a))
         arising from a static form
         (maybe you haven't applied a function to enough arguments?)
diff --git a/testsuite/tests/typecheck/should_fail/tcfail182.stderr b/testsuite/tests/typecheck/should_fail/tcfail182.stderr
index 35e2e2d2c9..e57c3c1672 100644
--- a/testsuite/tests/typecheck/should_fail/tcfail182.stderr
+++ b/testsuite/tests/typecheck/should_fail/tcfail182.stderr
@@ -4,7 +4,7 @@ tcfail182.hs:9:3: error:
                   with actual type ‘Maybe a0’
       NB: ‘Maybe’ is defined at tcfail182.hs:6:1-18
           ‘Prelude.Maybe’
-            is defined in ‘GHC.Maybe’ in package ‘base-4.12.0.0’
+            is defined in ‘GHC.Maybe’ in package ‘base-4.13.0.0’
     • In the pattern: Foo
       In an equation for ‘f’: f Foo = 3
     • Relevant bindings include
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