[Git][ghc/ghc][wip/eqtycon-rn] Export (~) from Data.Type.Equality (#18862)
Vladislav Zavialov
gitlab at gitlab.haskell.org
Sun Oct 18 15:35:07 UTC 2020
Vladislav Zavialov pushed to branch wip/eqtycon-rn at Glasgow Haskell Compiler / GHC
Commits:
8c1aa21f by Vladislav Zavialov at 2020-10-18T18:34:50+03:00
Export (~) from Data.Type.Equality (#18862)
* Users can define their own (~) type operator
* Haddock can display documentation for the built-in (~)
Updates the haddock submodule.
- - - - -
14 changed files:
- compiler/GHC/Builtin/Names.hs
- compiler/GHC/Builtin/Types.hs
- compiler/GHC/Parser.y
- compiler/GHC/Parser/PostProcess.hs
- compiler/GHC/Rename/Env.hs
- libraries/base/Data/Type/Equality.hs
- libraries/base/GHC/Exts.hs
- libraries/ghc-prim/GHC/Types.hs
- testsuite/tests/rename/should_fail/T15214.hs → testsuite/tests/rename/should_compile/T15214.hs
- + testsuite/tests/rename/should_compile/T18862.hs
- testsuite/tests/rename/should_compile/all.T
- − testsuite/tests/rename/should_fail/T15214.stderr
- testsuite/tests/rename/should_fail/all.T
- utils/haddock
Changes:
=====================================
compiler/GHC/Builtin/Names.hs
=====================================
@@ -2600,4 +2600,5 @@ pretendNameIsInScope :: Name -> Bool
pretendNameIsInScope n
= any (n `hasKey`)
[ liftedTypeKindTyConKey, tYPETyConKey
- , runtimeRepTyConKey, liftedRepDataConKey ]
+ , runtimeRepTyConKey, liftedRepDataConKey
+ , eqTyConKey ]
=====================================
compiler/GHC/Builtin/Types.hs
=====================================
@@ -295,18 +295,14 @@ eqSCSelIdName = mkWiredInIdName gHC_TYPES (fsLit "eq_sel") eqSCSelIdKey eqSCSelI
The (~) type operator used in equality constraints (a~b) is considered built-in
syntax. This has a few consequences:
-* The user is not allowed to define their own type constructors with this name:
-
- ghci> class a ~ b
- <interactive>:1:1: error: Illegal binding of built-in syntax: ~
-
* Writing (a ~ b) does not require enabling -XTypeOperators. It does, however,
require -XGADTs or -XTypeFamilies.
* The (~) type operator is always in scope. It doesn't need to be imported,
and it cannot be hidden.
-* We have a bunch of special cases in the compiler to arrange all of the above.
+In the past, users also could not define their own (~), but this restriction
+has been lifted.
There's no particular reason for (~) to be special, but fixing this would be a
breaking change.
=====================================
compiler/GHC/Parser.y
=====================================
@@ -87,7 +87,7 @@ import GHC.Parser.Errors
import GHC.Builtin.Types ( unitTyCon, unitDataCon, tupleTyCon, tupleDataCon, nilDataCon,
unboxedUnitTyCon, unboxedUnitDataCon,
- listTyCon_RDR, consDataCon_RDR, eqTyCon_RDR)
+ listTyCon_RDR, consDataCon_RDR )
}
%expect 0 -- shift/reduce conflicts
@@ -3517,11 +3517,7 @@ qtyconsym :: { Located RdrName }
tyconsym :: { Located RdrName }
: CONSYM { sL1 $1 $! mkUnqual tcClsName (getCONSYM $1) }
- | VARSYM { sL1 $1 $!
- -- See Note [eqTyCon (~) is built-in syntax] in GHC.Builtin.Types
- if getVARSYM $1 == fsLit "~"
- then eqTyCon_RDR
- else mkUnqual tcClsName (getVARSYM $1) }
+ | VARSYM { sL1 $1 $! mkUnqual tcClsName (getVARSYM $1) }
| ':' { sL1 $1 $! consDataCon_RDR }
| '-' { sL1 $1 $! mkUnqual tcClsName (fsLit "-") }
| '.' { sL1 $1 $! mkUnqual tcClsName (fsLit ".") }
=====================================
compiler/GHC/Parser/PostProcess.hs
=====================================
@@ -121,7 +121,7 @@ import GHC.Utils.Lexeme ( isLexCon )
import GHC.Core.Type ( TyThing(..), unrestrictedFunTyCon, Specificity(..) )
import GHC.Builtin.Types( cTupleTyConName, tupleTyCon, tupleDataCon,
nilDataConName, nilDataConKey,
- listTyConName, listTyConKey, eqTyCon_RDR )
+ listTyConName, listTyConKey )
import GHC.Types.ForeignCall
import GHC.Types.SrcLoc
import GHC.Types.Unique ( hasKey )
@@ -2128,8 +2128,7 @@ checkPrecP (L l (_,i)) (L _ ol)
| otherwise = addFatalError $ Error (ErrPrecedenceOutOfRange i) [] l
where
-- If you change this, consider updating Note [Fixity of (->)] in GHC/Types.hs
- specialOp op = unLoc op `elem` [ eqTyCon_RDR
- , getRdrName unrestrictedFunTyCon ]
+ specialOp op = unLoc op `elem` [ getRdrName unrestrictedFunTyCon ]
mkRecConstrOrUpdate
:: LHsExpr GhcPs
=====================================
compiler/GHC/Rename/Env.hs
=====================================
@@ -90,6 +90,7 @@ import qualified Data.Semigroup as Semi
import Data.Either ( partitionEithers )
import Data.List ( find, sortBy )
import Control.Arrow ( first )
+import Control.Applicative ( (<|>) )
import Data.Function
{-
@@ -963,10 +964,16 @@ lookupTypeOccRn rdr_name
= badVarInType rdr_name
| otherwise
= do { mb_name <- lookupOccRn_maybe rdr_name
- ; case mb_name of
+ ; case mb_name <|> matchEqTyName rdr_name of
Just name -> return name
Nothing -> lookup_demoted rdr_name }
+-- See Note [eqTyCon (~) is built-in syntax] in GHC.Builtin.Types
+matchEqTyName :: RdrName -> Maybe Name
+matchEqTyName rdr_name
+ | occName rdr_name == occName eqTyCon_RDR = Just eqTyConName
+ | otherwise = Nothing
+
lookup_demoted :: RdrName -> RnM Name
lookup_demoted rdr_name
| Just demoted_rdr <- demoteRdrName rdr_name
@@ -1153,6 +1160,7 @@ lookupInfoOccRn rdr_name =
lookupExactOrOrig rdr_name (:[]) $
do { rdr_env <- getGlobalRdrEnv
; let ns = map gre_name (lookupGRE_RdrName rdr_name rdr_env)
+ ++ maybeToList (matchEqTyName rdr_name)
; qual_ns <- lookupQualifiedNameGHCi rdr_name
; return (ns ++ (qual_ns `minusList` ns)) }
@@ -1655,13 +1663,7 @@ dataTcOccs rdr_name
= [rdr_name]
where
occ = rdrNameOcc rdr_name
- rdr_name_tc =
- case rdr_name of
- -- The (~) type operator is always in scope, so we need a special case
- -- for it here, or else :info (~) fails in GHCi.
- -- See Note [eqTyCon (~) is built-in syntax]
- Unqual occ | occNameFS occ == fsLit "~" -> eqTyCon_RDR
- _ -> setRdrNameSpace rdr_name tcName
+ rdr_name_tc = setRdrNameSpace rdr_name tcName
{-
Note [dataTcOccs and Exact Names]
=====================================
libraries/base/Data/Type/Equality.hs
=====================================
@@ -31,7 +31,9 @@
module Data.Type.Equality (
-- * The equality types
- (:~:)(..), type (~~),
+ type (~),
+ type (~~),
+ (:~:)(..),
(:~~:)(..),
-- * Working with equality
=====================================
libraries/base/GHC/Exts.hs
=====================================
@@ -88,6 +88,7 @@ module GHC.Exts
unsafeCoerce#,
-- * Equality
+ type (~),
type (~~),
-- * Representation polymorphism
=====================================
libraries/ghc-prim/GHC/Types.hs
=====================================
@@ -32,7 +32,7 @@ module GHC.Types (
SPEC(..),
Symbol,
Any,
- type (~~), Coercible,
+ type (~), type (~~), Coercible,
TYPE, RuntimeRep(..), Type, Constraint,
-- The historical type * should ideally be written as
-- `type *`, without the parentheses. But that's a true
@@ -225,7 +225,6 @@ newtype IO a = IO (State# RealWorld -> (# State# RealWorld, a #))
* *
(~) and Coercible
- NB: (~) is built-in syntax, and hence not explicitly exported
* *
********************************************************************* -}
=====================================
testsuite/tests/rename/should_fail/T15214.hs → testsuite/tests/rename/should_compile/T15214.hs
=====================================
=====================================
testsuite/tests/rename/should_compile/T18862.hs
=====================================
@@ -0,0 +1,11 @@
+{-# LANGUAGE PolyKinds, DataKinds, TypeOperators, TypeFamilies #-}
+
+module T18862 where
+
+import Data.Kind (Constraint)
+import qualified Data.Type.Equality as E
+
+type family (a :: k) ~ (b :: k) :: result_kind
+
+type instance a ~ b = (a E.~ b :: Constraint)
+type instance a ~ b = (a E.== b :: Bool)
=====================================
testsuite/tests/rename/should_compile/all.T
=====================================
@@ -162,6 +162,7 @@ test('T14881', [], multimod_compile, ['T14881', '-W'])
test('T14487', [], multimod_compile, ['T14487', '-v0'])
test('T14747', [], multimod_compile, ['T14747', '-v0'])
test('T15149', [], multimod_compile, ['T15149', '-v0'])
+test('T15214', normal, compile, [''])
test('T13064', normal, compile, [''])
test('T15994', [], makefile_test, ['T15994'])
test('T15798a', normal, compile, [''])
@@ -177,3 +178,4 @@ test('T17837', normal, compile, [''])
test('T18497', [], makefile_test, ['T18497'])
test('T18264', [], makefile_test, ['T18264'])
test('T18302', expect_broken(18302), compile, [''])
+test('T18862', normal, compile, [''])
=====================================
testsuite/tests/rename/should_fail/T15214.stderr deleted
=====================================
@@ -1,2 +0,0 @@
-
-T15214.hs:4:1: error: Illegal binding of built-in syntax: ~
=====================================
testsuite/tests/rename/should_fail/all.T
=====================================
@@ -135,7 +135,6 @@ test('T14307', normal, compile_fail, [''])
test('T14591', normal, compile_fail, [''])
test('T14907a', normal, compile_fail, [''])
test('T14907b', normal, compile_fail, [''])
-test('T15214', normal, compile_fail, [''])
test('T15539', normal, compile_fail, [''])
test('T15487', normal, multimod_compile_fail, ['T15487','-v0'])
test('T15659', normal, compile_fail, [''])
=====================================
utils/haddock
=====================================
@@ -1 +1 @@
-Subproject commit f7d9e0bb987ca31c3b15cbe63198dafbeee3a395
+Subproject commit 75226997a379981cf2e343e166094887bb3a8295
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/8c1aa21f2dc3858e09e0432ee38bdb3f3c01bd5a
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/8c1aa21f2dc3858e09e0432ee38bdb3f3c01bd5a
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