[Git][ghc/ghc][master] 5 commits: Export liftA2 from Prelude
Marge Bot (@marge-bot)
gitlab at gitlab.haskell.org
Thu Sep 8 21:49:27 UTC 2022
Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC
Commits:
77209ab3 by Georgi Lyubenov at 2022-09-08T17:14:36+03:00
Export liftA2 from Prelude
Changes:
In order to be warning free and compatible, we hide Applicative(..)
from Prelude in a few places and instead import it directly from
Control.Applicative.
Please see the migration guide at
https://github.com/haskell/core-libraries-committee/blob/main/guides/export-lifta2-prelude.md
for more details.
This means that Applicative is now exported in its entirety from
Prelude.
Motivation:
This change is motivated by a few things:
* liftA2 is an often used function, even more so than (<*>) for some
people.
* When implementing Applicative, the compiler will prompt you for either
an implementation of (<*>) or of liftA2, but trying to use the latter
ends with an error, without further imports. This could be confusing
for newbies.
* For teaching, it is often times easier to introduce liftA2 first,
as it is a natural generalisation of fmap.
* This change seems to have been unanimously and enthusiastically
accepted by the CLC members, possibly indicating a lot of love for it.
* This change causes very limited breakage, see the linked issue below
for an investigation on this.
See https://github.com/haskell/core-libraries-committee/issues/50
for the surrounding discussion and more details.
- - - - -
442a94e8 by Georgi Lyubenov at 2022-09-08T17:14:36+03:00
Add changelog entry for liftA2 export from Prelude
- - - - -
fb968680 by Georgi Lyubenov at 2022-09-08T17:14:36+03:00
Bump submodule containers to one with liftA2 warnings fixed
- - - - -
f54ff818 by Georgi Lyubenov at 2022-09-08T17:14:36+03:00
Bump submodule Cabal to one with liftA2 warnings fixed
- - - - -
a4b34808 by Georgi Lyubenov at 2022-09-08T17:14:36+03:00
Isolate some Applicative hidings to GHC.Prelude
By reexporting the entirety of Applicative from GHC.Prelude, we can save
ourselves some `hiding` and importing of `Applicative` in consumers of GHC.Prelude.
This also has the benefit of isolating this type of change to
GHC.Prelude, so that people in the future don't have to think about it.
- - - - -
15 changed files:
- compiler/GHC/Hs/Doc.hs
- compiler/GHC/Prelude.hs
- compiler/GHC/Types/SrcLoc.hs
- compiler/GHC/Utils/Misc.hs
- compiler/GHC/Utils/Monad.hs
- libraries/Cabal
- libraries/base/Data/Complex.hs
- libraries/base/Data/List/NonEmpty.hs
- libraries/base/Data/Semigroup.hs
- libraries/base/Prelude.hs
- libraries/base/changelog.md
- libraries/containers
- libraries/template-haskell/Language/Haskell/TH/Lib.hs
- libraries/template-haskell/Language/Haskell/TH/Lib/Internal.hs
- libraries/template-haskell/Language/Haskell/TH/Syntax.hs
Changes:
=====================================
compiler/GHC/Hs/Doc.hs
=====================================
@@ -38,7 +38,6 @@ import GHC.Types.Avail
import GHC.Types.Name.Set
import GHC.Driver.Flags
-import Control.Applicative (liftA2)
import Data.Data
import Data.IntMap (IntMap)
import qualified Data.IntMap as IntMap
=====================================
compiler/GHC/Prelude.hs
=====================================
@@ -14,6 +14,7 @@
module GHC.Prelude
(module X
+ ,Applicative (..)
,module Bits
,shiftL, shiftR
) where
@@ -47,7 +48,8 @@ NoImplicitPrelude. There are two motivations for this:
extensions.
-}
-import Prelude as X hiding ((<>))
+import Prelude as X hiding ((<>), Applicative(..))
+import Control.Applicative (Applicative(..))
import Data.Foldable as X (foldl')
#if MIN_VERSION_base(4,16,0)
=====================================
compiler/GHC/Types/SrcLoc.hs
=====================================
@@ -125,7 +125,6 @@ import GHC.Data.FastString
import qualified GHC.Data.Strict as Strict
import Control.DeepSeq
-import Control.Applicative (liftA2)
import Data.Data
import Data.List (sortBy, intercalate)
import Data.Function (on)
=====================================
compiler/GHC/Utils/Misc.hs
=====================================
@@ -141,7 +141,6 @@ import Data.List.NonEmpty ( NonEmpty(..) )
import GHC.Exts
import GHC.Stack (HasCallStack)
-import Control.Applicative ( liftA2 )
import Control.Monad ( liftM, guard )
import Control.Monad.IO.Class ( MonadIO, liftIO )
import System.IO.Error as IO ( isDoesNotExistError )
=====================================
compiler/GHC/Utils/Monad.hs
=====================================
@@ -29,7 +29,6 @@ module GHC.Utils.Monad
import GHC.Prelude
-import Control.Applicative
import Control.Monad
import Control.Monad.Fix
import Control.Monad.IO.Class
=====================================
libraries/Cabal
=====================================
@@ -1 +1 @@
-Subproject commit 5d18b763356dca719f5286a52328cb41b9fa4192
+Subproject commit dac10555299fa0d750838529a67598821264e5e3
=====================================
libraries/base/Data/Complex.hs
=====================================
@@ -35,6 +35,7 @@ module Data.Complex
) where
+import Prelude hiding (Applicative(..))
import GHC.Base (Applicative (..))
import GHC.Generics (Generic, Generic1)
import GHC.Float (Floating(..))
=====================================
libraries/base/Data/List/NonEmpty.hs
=====================================
@@ -102,7 +102,7 @@ import Prelude hiding (break, cycle, drop, dropWhile,
last, length, map, repeat, reverse,
scanl, scanl1, scanr, scanr1, span,
splitAt, tail, take, takeWhile,
- unzip, zip, zipWith, (!!))
+ unzip, zip, zipWith, (!!), Applicative(..))
import qualified Prelude
import Control.Applicative (Applicative (..), Alternative (many))
=====================================
libraries/base/Data/Semigroup.hs
=====================================
@@ -98,7 +98,7 @@ module Data.Semigroup (
, ArgMax
) where
-import Prelude hiding (foldr1)
+import Prelude hiding (foldr1, Applicative(..))
import GHC.Base (Semigroup(..))
=====================================
libraries/base/Prelude.hs
=====================================
@@ -73,7 +73,7 @@ module Prelude (
-- ** Monads and functors
Functor(fmap, (<$)), (<$>),
- Applicative(pure, (<*>), (*>), (<*)),
+ Applicative(pure, (<*>), (*>), (<*), liftA2),
Monad((>>=), (>>), return),
MonadFail(fail),
mapM_, sequence_, (=<<),
=====================================
libraries/base/changelog.md
=====================================
@@ -25,6 +25,10 @@
* Change default `Ord` implementation of `(>=)`, `(>)`, and `(<)` to use
`(<=)` instead of `compare` per
[Core Libraries proposal](https://github.com/haskell/core-libraries-committee/issues/24).
+ * Export `liftA2` from `Prelude`. This means that the entirety of `Applicative`
+ is now exported from `Prelude`. See [CLC #50](https://github.com/haskell/core-libraries-committee/issues/50)
+ for the related discussion,
+ as well as [the migration guide](https://github.com/haskell/core-libraries-committee/blob/main/guides/export-lifta2-prelude.md)
## 4.17.0.0 *August 2022*
=====================================
libraries/containers
=====================================
@@ -1 +1 @@
-Subproject commit 50175b72dc781f82a419bddafba1bdd758fbee4b
+Subproject commit 5e338df84454b56d649360a57d2c186785aff2b4
=====================================
libraries/template-haskell/Language/Haskell/TH/Lib.hs
=====================================
@@ -178,10 +178,10 @@ import Language.Haskell.TH.Lib.Internal hiding
import qualified Language.Haskell.TH.Lib.Internal as Internal
import Language.Haskell.TH.Syntax
-import Control.Applicative ( liftA2 )
+import Control.Applicative (Applicative(..))
import Foreign.ForeignPtr
import Data.Word
-import Prelude
+import Prelude hiding (Applicative(..))
-- All definitions below represent the "old" API, since their definitions are
-- different in Language.Haskell.TH.Lib.Internal. Please think carefully before
=====================================
libraries/template-haskell/Language/Haskell/TH/Lib/Internal.hs
=====================================
@@ -20,12 +20,12 @@ module Language.Haskell.TH.Lib.Internal where
import Language.Haskell.TH.Syntax hiding (Role, InjectivityAnn)
import qualified Language.Haskell.TH.Syntax as TH
-import Control.Applicative(liftA, liftA2)
+import Control.Applicative(liftA, Applicative(..))
import qualified Data.Kind as Kind (Type)
import Data.Word( Word8 )
import Data.List.NonEmpty ( NonEmpty(..) )
import GHC.Exts (TYPE)
-import Prelude
+import Prelude hiding (Applicative(..))
----------------------------------------------------------
-- * Type synonyms
=====================================
libraries/template-haskell/Language/Haskell/TH/Syntax.hs
=====================================
@@ -39,7 +39,7 @@ import GHC.IO.Unsafe ( unsafeDupableInterleaveIO )
import Control.Monad (liftM)
import Control.Monad.IO.Class (MonadIO (..))
import Control.Monad.Fix (MonadFix (..))
-import Control.Applicative (liftA2)
+import Control.Applicative (Applicative(..))
import Control.Exception (BlockedIndefinitelyOnMVar (..), catch, throwIO)
import Control.Exception.Base (FixIOException (..))
import Control.Concurrent.MVar (newEmptyMVar, readMVar, putMVar)
@@ -60,7 +60,7 @@ import GHC.Lexeme ( startsVarSym, startsVarId )
import GHC.ForeignSrcLang.Type
import Language.Haskell.TH.LanguageExtensions
import Numeric.Natural
-import Prelude
+import Prelude hiding (Applicative(..))
import Foreign.ForeignPtr
import Foreign.C.String
import Foreign.C.Types
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/7918265d53db963bfd3dd529b1063fb844549733...a4b34808720e93b434b4fcf18db114bc1f0599aa
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/7918265d53db963bfd3dd529b1063fb844549733...a4b34808720e93b434b4fcf18db114bc1f0599aa
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