diff --git a/libraries/base/Control/Monad/Fix.hs b/libraries/base/Control/Monad/Fix.hs
index 4c333c32edf37c5d7cdbecc268bb8200698f3dde..bb269847b6a011e3f671969a6f300b2af680a26b 100644
--- a/libraries/base/Control/Monad/Fix.hs
+++ b/libraries/base/Control/Monad/Fix.hs
@@ -29,6 +29,7 @@ import Data.Function ( fix )
import Data.Maybe
import Data.Monoid ( Dual(..), Sum(..), Product(..)
, First(..), Last(..), Alt(..), Ap(..) )
+import Data.Ord ( Down(..) )
import GHC.Base ( Monad, NonEmpty(..), errorWithoutStackTrace, (.) )
import GHC.Generics
import GHC.List ( head, tail )
@@ -149,3 +150,10 @@ instance (MonadFix f, MonadFix g) => MonadFix (f :*: g) where
where
fstP (a :*: _) = a
sndP (_ :*: b) = b
+
+-- Instances for Data.Ord
+
+-- | @since 4.12.0.0
+instance MonadFix Down where
+ mfix f = Down (fix (getDown . f))
+ where getDown (Down x) = x
diff --git a/libraries/base/Control/Monad/Zip.hs b/libraries/base/Control/Monad/Zip.hs
index d484d1fa8358cf2e01ccc23123d293311bada1e9..beef913119cb607af63a23d79c95cab1aaa2e4a3 100644
--- a/libraries/base/Control/Monad/Zip.hs
+++ b/libraries/base/Control/Monad/Zip.hs
@@ -21,6 +21,7 @@ module Control.Monad.Zip where
import Control.Monad (liftM, liftM2)
import Data.Functor.Identity
import Data.Monoid
+import Data.Ord ( Down(..) )
import Data.Proxy
import qualified Data.List.NonEmpty as NE
import GHC.Generics
@@ -124,3 +125,9 @@ instance MonadZip f => MonadZip (M1 i c f) where
-- | @since 4.9.0.0
instance (MonadZip f, MonadZip g) => MonadZip (f :*: g) where
mzipWith f (x1 :*: y1) (x2 :*: y2) = mzipWith f x1 x2 :*: mzipWith f y1 y2
+
+-- instances for Data.Ord
+
+-- | @since 4.12.0.0
+instance MonadZip Down where
+ mzipWith = liftM2
diff --git a/libraries/base/Data/Data.hs b/libraries/base/Data/Data.hs
index 194df0800391fb44a816c483e6238903846e7a02..fa199f1117ffd5a9266ed74eec9e003286699575 100644
--- a/libraries/base/Data/Data.hs
+++ b/libraries/base/Data/Data.hs
@@ -1334,3 +1334,9 @@ deriving instance Data SourceStrictness
-- | @since 4.9.0.0
deriving instance Data DecidedStrictness
+
+----------------------------------------------------------------------------
+-- Data instances for Data.Ord
+
+-- | @since 4.12.0.0
+deriving instance Data a => Data (Down a)
diff --git a/libraries/base/Data/Foldable.hs b/libraries/base/Data/Foldable.hs
index 47f22e343bbf10210d6e8edf29683194ce3355e3..847eb56dcfe23d77a4ceba840611f726ce94653a 100644
--- a/libraries/base/Data/Foldable.hs
+++ b/libraries/base/Data/Foldable.hs
@@ -505,6 +505,10 @@ deriving instance Foldable UInt
-- | @since 4.9.0.0
deriving instance Foldable UWord
+-- Instances for Data.Ord
+-- | @since 4.12.0.0
+deriving instance Foldable Down
+
-- | Monadic fold over the elements of a structure,
-- associating to the right, i.e. from right to left.
foldrM :: (Foldable t, Monad m) => (a -> b -> m b) -> b -> t a -> m b
diff --git a/libraries/base/Data/Functor/Classes.hs b/libraries/base/Data/Functor/Classes.hs
index 32d9929e32e8a420ec5becb532f7c38b617535e2..e44c817b641abf928fd8626f0a232451bcc527e5 100644
--- a/libraries/base/Data/Functor/Classes.hs
+++ b/libraries/base/Data/Functor/Classes.hs
@@ -70,6 +70,7 @@ import Data.Functor.Identity (Identity(Identity))
import Data.Proxy (Proxy(Proxy))
import Data.List.NonEmpty (NonEmpty(..))
import Data.Monoid (mappend)
+import Data.Ord (Down(Down))
import GHC.Read (expectP, list, paren)
@@ -644,6 +645,24 @@ instance Read1 Proxy where
liftReadListPrec = liftReadListPrecDefault
liftReadList = liftReadListDefault
+-- | @since 4.12.0.0
+instance Eq1 Down where
+ liftEq eq (Down x) (Down y) = eq x y
+
+-- | @since 4.12.0.0
+instance Ord1 Down where
+ liftCompare comp (Down x) (Down y) = comp x y
+
+-- | @since 4.12.0.0
+instance Read1 Down where
+ liftReadsPrec rp _ = readsData $
+ readsUnaryWith rp "Down" Down
+
+-- | @since 4.12.0.0
+instance Show1 Down where
+ liftShowsPrec sp _ d (Down x) = showsUnaryWith sp "Down" d x
+
+
-- Building blocks
-- | @'readsData' p d@ is a parser for datatypes where each alternative
diff --git a/libraries/base/Data/Traversable.hs b/libraries/base/Data/Traversable.hs
index bed2ef93ab30aa089a3027ee14df58d8e2c84c1c..5e88dc7dd1a9bc7be97c20a22f9e3f730182b272 100644
--- a/libraries/base/Data/Traversable.hs
+++ b/libraries/base/Data/Traversable.hs
@@ -62,6 +62,7 @@ import Data.Functor.Identity ( Identity(..) )
import Data.Functor.Utils ( StateL(..), StateR(..) )
import Data.Monoid ( Dual(..), Sum(..), Product(..),
First(..), Last(..), Alt(..), Ap(..) )
+import Data.Ord ( Down(..) )
import Data.Proxy ( Proxy(..) )
import GHC.Arr
@@ -360,6 +361,10 @@ deriving instance Traversable UInt
-- | @since 4.9.0.0
deriving instance Traversable UWord
+-- Instance for Data.Ord
+-- | @since 4.12.0.0
+deriving instance Traversable Down
+
-- general functions
-- | 'for' is 'traverse' with its arguments flipped. For a version
diff --git a/libraries/base/GHC/Generics.hs b/libraries/base/GHC/Generics.hs
index 05a96b98ebfc6610d66b818334d3d37630eab61e..34425f2b5f80b61084dfbb9396e50a9d14a1c26e 100644
--- a/libraries/base/GHC/Generics.hs
+++ b/libraries/base/GHC/Generics.hs
@@ -731,6 +731,7 @@ module GHC.Generics (
-- We use some base types
import Data.Either ( Either (..) )
import Data.Maybe ( Maybe(..), fromMaybe )
+import Data.Ord ( Down(..) )
import GHC.Integer ( Integer, integerToInt )
import GHC.Prim ( Addr#, Char#, Double#, Float#, Int#, Word# )
import GHC.Ptr ( Ptr )
@@ -1435,6 +1436,9 @@ deriving instance Generic ((,,,,,) a b c d e f)
-- | @since 4.6.0.0
deriving instance Generic ((,,,,,,) a b c d e f g)
+-- | @since 4.12.0.0
+deriving instance Generic (Down a)
+
-- | @since 4.6.0.0
deriving instance Generic1 []
@@ -1469,6 +1473,9 @@ deriving instance Generic1 ((,,,,,) a b c d e)
-- | @since 4.6.0.0
deriving instance Generic1 ((,,,,,,) a b c d e f)
+-- | @since 4.12.0.0
+deriving instance Generic1 Down
+
--------------------------------------------------------------------------------
-- Copied from the singletons package
--------------------------------------------------------------------------------
diff --git a/libraries/base/changelog.md b/libraries/base/changelog.md
index 9e896d367177a637d0d23fd4771976518b638ee6..43bdf0256c68818231d303ddeb10476e1a2b6c83 100644
--- a/libraries/base/changelog.md
+++ b/libraries/base/changelog.md
@@ -37,6 +37,11 @@
* `Control.Exception.throw` is now levity polymorphic. (#15180)
+ * `Data.Ord.Down` now has a number of new instances. These include:
+ `MonadFix`, `MonadZip`, `Data`, `Foldable`, `Traversable`, `Eq1`, `Ord1`,
+ `Read1`, `Show1`, `Generic`, `Generic1`. (#15098)
+
+
## 4.11.1.0 *TBA*
* Bundled with GHC 8.4.2
diff --git a/testsuite/tests/annotations/should_fail/annfail10.stderr b/testsuite/tests/annotations/should_fail/annfail10.stderr
index 9aa4c4047f14f350c117e63e4d5e9523145a3d30..d29a861566cd4456d672298ae8fafc667a80af93 100644
--- a/testsuite/tests/annotations/should_fail/annfail10.stderr
+++ b/testsuite/tests/annotations/should_fail/annfail10.stderr
@@ -10,7 +10,7 @@ annfail10.hs:9:1: error:
instance Data.Data.Data Ordering -- Defined in ‘Data.Data’
instance Data.Data.Data Integer -- Defined in ‘Data.Data’
...plus 15 others
- ...plus 46 instances involving out-of-scope types
+ ...plus 47 instances involving out-of-scope types
(use -fprint-potential-instances to see them all)
• In the annotation: {-# ANN f 1 #-}
@@ -23,6 +23,6 @@ annfail10.hs:9:11: error:
instance Num Double -- Defined in ‘GHC.Float’
instance Num Float -- Defined in ‘GHC.Float’
...plus two others
- ...plus 18 instances involving out-of-scope types
+ ...plus 19 instances involving out-of-scope types
(use -fprint-potential-instances to see them all)
• In the annotation: {-# ANN f 1 #-}
diff --git a/testsuite/tests/ghci/scripts/T10963.stderr b/testsuite/tests/ghci/scripts/T10963.stderr
index de0b094ac42c997bdd76b4eaeb7fa8aa3ee45974..2efd138be8032f41342cb44102dc3fb53e9114ad 100644
--- a/testsuite/tests/ghci/scripts/T10963.stderr
+++ b/testsuite/tests/ghci/scripts/T10963.stderr
@@ -8,5 +8,5 @@
instance Num Double -- Defined in ‘GHC.Float’
instance Num Float -- Defined in ‘GHC.Float’
...plus two others
- ...plus 7 instances involving out-of-scope types
+ ...plus 8 instances involving out-of-scope types
(use -fprint-potential-instances to see them all)
diff --git a/testsuite/tests/polykinds/T13393.stderr b/testsuite/tests/polykinds/T13393.stderr
index 1c4294e8a30e7a5a5ee8bf4f9161b8886047abd0..beea4732ebf0dc588b1c4cce85bacded3401a21f 100644
--- a/testsuite/tests/polykinds/T13393.stderr
+++ b/testsuite/tests/polykinds/T13393.stderr
@@ -8,7 +8,7 @@ T13393.hs:61:3: error:
instance Traversable Identity -- Defined in ‘Data.Traversable’
instance Traversable Maybe -- Defined in ‘Data.Traversable’
...plus two others
- ...plus 27 instances involving out-of-scope types
+ ...plus 28 instances involving out-of-scope types
(use -fprint-potential-instances to see them all)
• In a stmt of a 'do' block:
mapM putBackLeftOverInputAndReturnOutput undefined
diff --git a/testsuite/tests/typecheck/should_compile/T14273.stderr b/testsuite/tests/typecheck/should_compile/T14273.stderr
index ca739a3ac753fe84770ccbc03cf7be23c21a974c..cb4be120f7b7178987105a57df6041c465dbeb48 100644
--- a/testsuite/tests/typecheck/should_compile/T14273.stderr
+++ b/testsuite/tests/typecheck/should_compile/T14273.stderr
@@ -12,7 +12,7 @@ T14273.hs:7:27: warning: [-Wdeferred-type-errors (in -Wdefault)]
instance Show Ordering -- Defined in ‘GHC.Show’
instance Show Integer -- Defined in ‘GHC.Show’
...plus 23 others
- ...plus 69 instances involving out-of-scope types
+ ...plus 70 instances involving out-of-scope types
(use -fprint-potential-instances to see them all)
• In the first argument of ‘Just’, namely ‘(show _a)’
In the expression: Just (show _a)
@@ -65,7 +65,7 @@ T14273.hs:13:10: warning: [-Wdeferred-type-errors (in -Wdefault)]
instance Show Ordering -- Defined in ‘GHC.Show’
instance Show Integer -- Defined in ‘GHC.Show’
...plus 23 others
- ...plus 69 instances involving out-of-scope types
+ ...plus 70 instances involving out-of-scope types
(use -fprint-potential-instances to see them all)
• In the expression: show (_h ++ [])
In an equation for ‘foo’: foo xs = show (_h ++ [])
diff --git a/testsuite/tests/typecheck/should_compile/holes2.stderr b/testsuite/tests/typecheck/should_compile/holes2.stderr
index 329e939c5d567d2b8679aeecb2dae37ef996524f..4ed5dfc552b4dc4730e7e397e7a8945376b07f9a 100644
--- a/testsuite/tests/typecheck/should_compile/holes2.stderr
+++ b/testsuite/tests/typecheck/should_compile/holes2.stderr
@@ -9,7 +9,7 @@ holes2.hs:3:5: warning: [-Wdeferred-type-errors (in -Wdefault)]
instance Show Ordering -- Defined in ‘GHC.Show’
instance Show Integer -- Defined in ‘GHC.Show’
...plus 23 others
- ...plus 69 instances involving out-of-scope types
+ ...plus 70 instances involving out-of-scope types
(use -fprint-potential-instances to see them all)
• In the expression: show _
In an equation for ‘f’: f = show _
diff --git a/testsuite/tests/typecheck/should_compile/valid_hole_fits.stderr b/testsuite/tests/typecheck/should_compile/valid_hole_fits.stderr
index 17c487ffee9b160adf387fff00df8705ee8d17e2..6dde6ea5cff1a92e295143c4efe34a367995b9f6 100644
--- a/testsuite/tests/typecheck/should_compile/valid_hole_fits.stderr
+++ b/testsuite/tests/typecheck/should_compile/valid_hole_fits.stderr
@@ -98,7 +98,7 @@ valid_hole_fits.hs:30:5: warning: [-Wdeferred-type-errors (in -Wdefault)]
instance Show Ordering -- Defined in ‘GHC.Show’
instance Show Integer -- Defined in ‘GHC.Show’
...plus 23 others
- ...plus 69 instances involving out-of-scope types
+ ...plus 70 instances involving out-of-scope types
(use -fprint-potential-instances to see them all)
• In the expression: show _
In an equation for ‘f’: f = show _
@@ -148,7 +148,7 @@ valid_hole_fits.hs:34:5: warning: [-Wdeferred-type-errors (in -Wdefault)]
instance Show Ordering -- Defined in ‘GHC.Show’
instance Show Integer -- Defined in ‘GHC.Show’
...plus 23 others
- ...plus 69 instances involving out-of-scope types
+ ...plus 70 instances involving out-of-scope types
(use -fprint-potential-instances to see them all)
• In the expression: show (_ (_ :: Bool))
In an equation for ‘h’: h = show (_ (_ :: Bool))
diff --git a/testsuite/tests/typecheck/should_fail/T10971b.stderr b/testsuite/tests/typecheck/should_fail/T10971b.stderr
index 42e8fab656879f42f098aae77462ae51f73d9d5f..3ac8c4400b2df8000d88afd1c1a7b9104b3ec317 100644
--- a/testsuite/tests/typecheck/should_fail/T10971b.stderr
+++ b/testsuite/tests/typecheck/should_fail/T10971b.stderr
@@ -11,7 +11,7 @@ T10971b.hs:4:11: error:
instance Foldable Maybe -- Defined in ‘Data.Foldable’
instance Foldable ((,) a) -- Defined in ‘Data.Foldable’
...plus one other
- ...plus 28 instances involving out-of-scope types
+ ...plus 29 instances involving out-of-scope types
(use -fprint-potential-instances to see them all)
• In the expression: length x
In the expression: \ x -> length x
@@ -29,7 +29,7 @@ T10971b.hs:5:13: error:
instance Traversable Maybe -- Defined in ‘Data.Traversable’
instance Traversable ((,) a) -- Defined in ‘Data.Traversable’
...plus one other
- ...plus 28 instances involving out-of-scope types
+ ...plus 29 instances involving out-of-scope types
(use -fprint-potential-instances to see them all)
• In the expression: fmapDefault f x
In the expression: \ f x -> fmapDefault f x
@@ -47,7 +47,7 @@ T10971b.hs:6:14: error:
instance Traversable Maybe -- Defined in ‘Data.Traversable’
instance Traversable ((,) a) -- Defined in ‘Data.Traversable’
...plus one other
- ...plus 28 instances involving out-of-scope types
+ ...plus 29 instances involving out-of-scope types
(use -fprint-potential-instances to see them all)
• In the expression: fmapDefault f x
In the expression: (fmapDefault f x, length x)
@@ -65,7 +65,7 @@ T10971b.hs:6:31: error:
instance Foldable Maybe -- Defined in ‘Data.Foldable’
instance Foldable ((,) a) -- Defined in ‘Data.Foldable’
...plus one other
- ...plus 28 instances involving out-of-scope types
+ ...plus 29 instances involving out-of-scope types
(use -fprint-potential-instances to see them all)
• In the expression: length x
In the expression: (fmapDefault f x, length x)
diff --git a/testsuite/tests/typecheck/should_fail/T12921.stderr b/testsuite/tests/typecheck/should_fail/T12921.stderr
index b6c14061cecb9a7ee9fd2c5f801fb908ed739f2f..d38ccf22b9e6a1984435ed42974252cfc9cfe5d6 100644
--- a/testsuite/tests/typecheck/should_fail/T12921.stderr
+++ b/testsuite/tests/typecheck/should_fail/T12921.stderr
@@ -10,7 +10,7 @@ T12921.hs:4:1: error:
instance Data.Data.Data Ordering -- Defined in ‘Data.Data’
instance Data.Data.Data Integer -- Defined in ‘Data.Data’
...plus 15 others
- ...plus 46 instances involving out-of-scope types
+ ...plus 47 instances involving out-of-scope types
(use -fprint-potential-instances to see them all)
• In the annotation:
{-# ANN module "HLint: ignore Reduce duplication" #-}
diff --git a/testsuite/tests/typecheck/should_fail/T14884.stderr b/testsuite/tests/typecheck/should_fail/T14884.stderr
index 89ddef9947c5f1e2b5332d0bb5f9e1cf3d1fd903..cb85da14a5870aadeef39aa162a94c6c9697df1f 100644
--- a/testsuite/tests/typecheck/should_fail/T14884.stderr
+++ b/testsuite/tests/typecheck/should_fail/T14884.stderr
@@ -42,7 +42,7 @@ T14884.hs:4:7: error:
instance Show Ordering -- Defined in ‘GHC.Show’
instance Show Integer -- Defined in ‘GHC.Show’
...plus 23 others
- ...plus 66 instances involving out-of-scope types
+ ...plus 67 instances involving out-of-scope types
(use -fprint-potential-instances to see them all)
• In the first argument of ‘_’, namely ‘print’
In the expression: _ print "abc"