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-rw-r--r--compiler/hsSyn/PlaceHolder.hs12
-rw-r--r--compiler/main/DynFlags.hs5
-rw-r--r--compiler/rename/RnEnv.hs10
-rw-r--r--compiler/rename/RnSource.hs6
-rw-r--r--compiler/rename/RnTypes.hs2
-rw-r--r--docs/users_guide/8.0.1-notes.rst18
-rw-r--r--docs/users_guide/glasgow_exts.rst28
-rw-r--r--docs/users_guide/using-warnings.rst46
-rw-r--r--libraries/base/Data/Either.hs4
-rw-r--r--libraries/base/Data/Type/Bool.hs12
-rw-r--r--libraries/base/Data/Type/Equality.hs16
-rw-r--r--libraries/base/GHC/Generics.hs28
-rw-r--r--libraries/base/GHC/TypeLits.hs8
-rw-r--r--testsuite/tests/determinism/should_compile/determ004.hs6
-rw-r--r--testsuite/tests/indexed-types/should_compile/all.T4
-rw-r--r--testsuite/tests/simplCore/should_compile/T10689a.hs4
-rw-r--r--utils/mkUserGuidePart/Options/Warnings.hs12
17 files changed, 150 insertions, 71 deletions
diff --git a/compiler/hsSyn/PlaceHolder.hs b/compiler/hsSyn/PlaceHolder.hs
index 004f465d76..87736ac3d0 100644
--- a/compiler/hsSyn/PlaceHolder.hs
+++ b/compiler/hsSyn/PlaceHolder.hs
@@ -37,15 +37,15 @@ data PlaceHolder = PlaceHolder
-- | Types that are not defined until after type checking
type family PostTc it ty :: * -- Note [Pass sensitive types]
-type instance PostTc Id ty = ty
-type instance PostTc Name _ty = PlaceHolder
-type instance PostTc RdrName _ty = PlaceHolder
+type instance PostTc Id ty = ty
+type instance PostTc Name ty = PlaceHolder
+type instance PostTc RdrName ty = PlaceHolder
-- | Types that are not defined until after renaming
type family PostRn id ty :: * -- Note [Pass sensitive types]
-type instance PostRn Id ty = ty
-type instance PostRn Name ty = ty
-type instance PostRn RdrName _ty = PlaceHolder
+type instance PostRn Id ty = ty
+type instance PostRn Name ty = ty
+type instance PostRn RdrName ty = PlaceHolder
placeHolderKind :: PlaceHolder
placeHolderKind = PlaceHolder
diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs
index f6496d5fa6..22c2915960 100644
--- a/compiler/main/DynFlags.hs
+++ b/compiler/main/DynFlags.hs
@@ -562,6 +562,8 @@ data WarningFlag =
| Opt_WarnUnusedPatternBinds
| Opt_WarnUnusedImports
| Opt_WarnUnusedMatches
+ | Opt_WarnUnusedTypePatterns
+ | Opt_WarnUnusedForalls
| Opt_WarnContextQuantification -- remove in 8.2
| Opt_WarnWarningsDeprecations
| Opt_WarnDeprecatedFlags
@@ -2970,11 +2972,13 @@ wWarningFlags = [
flagSpec "unticked-promoted-constructors"
Opt_WarnUntickedPromotedConstructors,
flagSpec "unused-do-bind" Opt_WarnUnusedDoBind,
+ flagSpec "unused-foralls" Opt_WarnUnusedForalls,
flagSpec "unused-imports" Opt_WarnUnusedImports,
flagSpec "unused-local-binds" Opt_WarnUnusedLocalBinds,
flagSpec "unused-matches" Opt_WarnUnusedMatches,
flagSpec "unused-pattern-binds" Opt_WarnUnusedPatternBinds,
flagSpec "unused-top-binds" Opt_WarnUnusedTopBinds,
+ flagSpec "unused-type-patterns" Opt_WarnUnusedTypePatterns,
flagSpec "warnings-deprecations" Opt_WarnWarningsDeprecations,
flagSpec "wrong-do-bind" Opt_WarnWrongDoBind,
flagSpec "missing-pat-syn-sigs" Opt_WarnMissingPatSynSigs,
@@ -3512,6 +3516,7 @@ minusWOpts
Opt_WarnUnusedLocalBinds,
Opt_WarnUnusedPatternBinds,
Opt_WarnUnusedMatches,
+ Opt_WarnUnusedForalls,
Opt_WarnUnusedImports,
Opt_WarnIncompletePatterns,
Opt_WarnDodgyExports,
diff --git a/compiler/rename/RnEnv.hs b/compiler/rename/RnEnv.hs
index 0add967a35..d1ec1de6e6 100644
--- a/compiler/rename/RnEnv.hs
+++ b/compiler/rename/RnEnv.hs
@@ -41,7 +41,7 @@ module RnEnv (
checkDupNames, checkDupAndShadowedNames, dupNamesErr,
checkTupSize,
addFvRn, mapFvRn, mapMaybeFvRn, mapFvRnCPS,
- warnUnusedMatches,
+ warnUnusedMatches, warnUnusedTypePatterns,
warnUnusedTopBinds, warnUnusedLocalBinds,
mkFieldEnv,
dataTcOccs, kindSigErr, perhapsForallMsg, unknownSubordinateErr,
@@ -2072,9 +2072,11 @@ warnUnusedTopBinds gres
else gres
warnUnusedGREs gres'
-warnUnusedLocalBinds, warnUnusedMatches :: [Name] -> FreeVars -> RnM ()
-warnUnusedLocalBinds = check_unused Opt_WarnUnusedLocalBinds
-warnUnusedMatches = check_unused Opt_WarnUnusedMatches
+warnUnusedLocalBinds, warnUnusedMatches, warnUnusedTypePatterns
+ :: [Name] -> FreeVars -> RnM ()
+warnUnusedLocalBinds = check_unused Opt_WarnUnusedLocalBinds
+warnUnusedMatches = check_unused Opt_WarnUnusedMatches
+warnUnusedTypePatterns = check_unused Opt_WarnUnusedTypePatterns
check_unused :: WarningFlag -> [Name] -> FreeVars -> RnM ()
check_unused flag bound_names used_names
diff --git a/compiler/rename/RnSource.hs b/compiler/rename/RnSource.hs
index ad5418a046..98aacd0467 100644
--- a/compiler/rename/RnSource.hs
+++ b/compiler/rename/RnSource.hs
@@ -729,7 +729,7 @@ rnFamInstDecl doc mb_cls tycon (HsIB { hsib_body = pats }) payload rnPayload
-- appear *more than once* on the LHS
-- e.g. F a Int a = Bool
; let tv_nms_used = extendNameSetList rhs_fvs tv_nms_dups
- ; warnUnusedMatches var_names tv_nms_used
+ ; warnUnusedTypePatterns var_names tv_nms_used
-- See Note [Renaming associated types]
; let bad_tvs = case mb_cls of
@@ -854,7 +854,7 @@ fresh meta-variables whereas the former generate fresh skolems.
Note [Unused type variables in family instances]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-When the flag -fwarn-unused-matches is on, the compiler reports warnings
+When the flag -fwarn-unused-type-patterns is on, the compiler reports warnings
about unused type variables. (rnFamInstDecl) A type variable is considered
used
* when it is either occurs on the RHS of the family instance, or
@@ -869,7 +869,7 @@ beginning with an underscore.
Extra-constraints wild cards are not supported in type/data family
instance declarations.
-Relevant tickets: #3699, #10586 and #10982.
+Relevant tickets: #3699, #10586, #10982 and #11451.
Note [Renaming associated types]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/compiler/rename/RnTypes.hs b/compiler/rename/RnTypes.hs
index 0ddbf8ef0f..0d7f68c6b6 100644
--- a/compiler/rename/RnTypes.hs
+++ b/compiler/rename/RnTypes.hs
@@ -1400,7 +1400,7 @@ inTypeDoc ty = text "In the type" <+> quotes (ppr ty)
warnUnusedForAll :: SDoc -> LHsTyVarBndr Name -> FreeVars -> TcM ()
warnUnusedForAll in_doc (L loc tv) used_names
- = whenWOptM Opt_WarnUnusedMatches $
+ = whenWOptM Opt_WarnUnusedForalls $
unless (hsTyVarName tv `elemNameSet` used_names) $
addWarnAt loc $
vcat [ text "Unused quantified type variable" <+> quotes (ppr tv)
diff --git a/docs/users_guide/8.0.1-notes.rst b/docs/users_guide/8.0.1-notes.rst
index 6239ea5c52..b31223eef4 100644
--- a/docs/users_guide/8.0.1-notes.rst
+++ b/docs/users_guide/8.0.1-notes.rst
@@ -268,10 +268,20 @@ Compiler
a warning when a pattern synonym definition doesn't have a type signature.
It is turned off by default but enabled by :ghc-flag:`-Wall`.
-- Changed the :ghc-flag:`-fwarn-unused-matches` flag to report unused type variables
- in data and type families in addition to its previous behaviour.
- To avoid warnings, unused type variables should be prefixed or replaced with
- underscores.
+- Added the :ghc-flag:`-Wunused-type-patterns` flag to report unused
+ type variables in data and type family instances. This flag is not implied
+ by :ghc-flag:`-Wall`, since :ghc-flag:`-Wunused-type-patterns` will
+ warn about unused type variables even if the types themselves are intended
+ to be used as documentation. If :ghc-flag:`-Wunused-type-patterns` is
+ enabled, one can prefix or replace unused type variables with underscores to
+ avoid warnings.
+
+- Split off the new flag :ghc-flag:`-Wunused-foralls` from the previously
+ existing flag :ghc-flag:`-Wunused-matches`. :ghc-flag:`-Wunused-foralls`
+ emits a warning in the specific case that a user writes explicit ``forall``
+ syntax with unused type variables, while :ghc-flag:`-Wunused-matches` only
+ warns in the case of unused term-level patterns. Both flags are implied by
+ :ghc-flag:`-W`.
- Added the :ghc-flag:`-Wtoo-many-guards` flag. When enabled, this will issue a
warning if a pattern match contains too many guards (over 20 at the
diff --git a/docs/users_guide/glasgow_exts.rst b/docs/users_guide/glasgow_exts.rst
index 6d02391c16..6ea2ef65df 100644
--- a/docs/users_guide/glasgow_exts.rst
+++ b/docs/users_guide/glasgow_exts.rst
@@ -6035,12 +6035,13 @@ declaration doesn't matter, it can be replaced with an underscore
-- Equivalent to
data instance F Int b = Int
-When the flag :ghc-flag:`-fwarn-unused-matches` is enabled, type variables that are
-mentioned in the patterns on the left hand side, but not used on the right
-hand side are reported. Variables that occur multiple times on the left hand side
-are also considered used. To suppress the warnings, unused variables should
-be either replaced or prefixed with underscores. Type variables starting with
-an underscore (``_x``) are otherwise treated as ordinary type variables.
+When the flag :ghc-flag:`-Wunused-type-patterns` is enabled, type
+variables that are mentioned in the patterns on the left hand side, but not
+used on the right hand side are reported. Variables that occur multiple times
+on the left hand side are also considered used. To suppress the warnings,
+unused variables should be either replaced or prefixed with underscores. Type
+variables starting with an underscore (``_x``) are otherwise treated as
+ordinary type variables.
This resembles the wildcards that can be used in
:ref:`partial-type-signatures`. However, there are some differences.
@@ -6193,9 +6194,10 @@ for data instances. For example, the ``[e]`` instance for ``Elem`` is ::
Type arguments can be replaced with underscores (``_``) if the names of
the arguments don't matter. This is the same as writing type variables
-with unique names. Unused type arguments should be replaced or prefixed
-with underscores to avoid warnings when the `-fwarn-unused-matches` flag
-is enabled. The same rules apply as for :ref:`data-instance-declarations`.
+with unique names. Unused type arguments can be replaced or prefixed
+with underscores to avoid warnings when the
+:ghc-flag:`-Wunused-type-patterns` flag is enabled. The same rules apply
+as for :ref:`data-instance-declarations`.
Type family instance declarations are only legitimate when an
appropriate family declaration is in scope - just like class instances
@@ -7701,6 +7703,14 @@ The two are treated identically.
Of course ``forall`` becomes a keyword; you can't use ``forall`` as a
type variable any more!
+If the :ghc-flag:`-Wunused-foralls` flag is enabled, a warning will be emitted
+when you write a type variable in an explicit ``forall`` statement that is
+otherwise unused. For instance: ::
+
+ g :: forall a b. (b -> b)
+
+would warn about the unused type variable `a`.
+
.. _flexible-contexts:
The context of a type signature
diff --git a/docs/users_guide/using-warnings.rst b/docs/users_guide/using-warnings.rst
index e4f8d2c3a7..afcee5b5d7 100644
--- a/docs/users_guide/using-warnings.rst
+++ b/docs/users_guide/using-warnings.rst
@@ -44,6 +44,7 @@ The following flags are simple ways to select standard "packages" of warnings:
* :ghc-flag:`-Wunused-binds`
* :ghc-flag:`-Wunused-matches`
+ * :ghc-flag:`-Wunused-foralls`
* :ghc-flag:`-Wunused-imports`
* :ghc-flag:`-Wincomplete-patterns`
* :ghc-flag:`-Wdodgy-exports`
@@ -871,14 +872,18 @@ of ``-W(no-)*``.
single: unused matches, warning
single: matches, unused
- Report all unused variables which arise from pattern matches,
- including patterns consisting of a single variable. This includes
- unused type variables in type family instances. For instance
+ Report all unused variables which arise from term-level pattern matches,
+ including patterns consisting of a single variable. For instance
``f x y = []`` would report ``x`` and ``y`` as unused. The warning
is suppressed if the variable name begins with an underscore, thus: ::
f _x = True
+ Note that :ghc-flag:`-Wunused-matches` does not warn about variables which
+ arise from type-level patterns, as found in type family and data family
+ instances. This must be enabled separately through the
+ :ghc-flag:`-Wunused-type-patterns` flag.
+
.. ghc-flag:: -Wunused-do-bind
.. index::
@@ -900,6 +905,41 @@ of ``-W(no-)*``.
do { mapM_ popInt xs ; return 10 }
+.. ghc-flag:: -Wunused-type-patterns
+
+ .. index::
+ single: unused type patterns, warning
+ single: type patterns, unused
+
+ Report all unused type variables which arise from patterns in type family
+ and data family instances. For instance: ::
+
+ type instance F x y = []
+
+ would report ``x`` and ``y`` as unused. The warning is suppressed if the
+ type variable name begins with an underscore, like so: ::
+
+ type instance F _x _y = []
+
+ Unlike :ghc-flag:`-Wunused-matches`, :ghc-flag:`-Wunused-type-variables` is
+ not implied by :ghc-flag:`-Wall`. The rationale for this decision is that
+ unlike term-level pattern names, type names are often chosen expressly for
+ documentation purposes, so using underscores in type names can make the
+ documentation harder to read.
+
+.. ghc-flag:: -Wunused-foralls
+
+ .. index::
+ single: unused foralls, warning
+ single: foralls, unused
+
+ Report all unused type variables which arise from explicit, user-written
+ ``forall`` statements. For instance: ::
+
+ g :: forall a b c. (b -> b)
+
+ would report ``a`` and ``c`` as unused.
+
.. ghc-flag:: -Wwrong-do-bind
.. index::
diff --git a/libraries/base/Data/Either.hs b/libraries/base/Data/Either.hs
index 26cd7aa7fd..db340923e1 100644
--- a/libraries/base/Data/Either.hs
+++ b/libraries/base/Data/Either.hs
@@ -8,7 +8,7 @@
-- Module : Data.Either
-- Copyright : (c) The University of Glasgow 2001
-- License : BSD-style (see the file libraries/base/LICENSE)
---
+--
-- Maintainer : libraries@haskell.org
-- Stability : experimental
-- Portability : portable
@@ -281,7 +281,7 @@ isRight (Right _) = True
type family EqEither a b where
EqEither ('Left x) ('Left y) = x == y
EqEither ('Right x) ('Right y) = x == y
- EqEither _a _b = 'False
+ EqEither a b = 'False
type instance a == b = EqEither a b
{-
diff --git a/libraries/base/Data/Type/Bool.hs b/libraries/base/Data/Type/Bool.hs
index acac3eb592..cfd4bfada6 100644
--- a/libraries/base/Data/Type/Bool.hs
+++ b/libraries/base/Data/Type/Bool.hs
@@ -28,14 +28,14 @@ import Data.Bool
-- | Type-level "If". @If True a b@ ==> @a@; @If False a b@ ==> @b@
type family If cond tru fls where
- If 'True tru _fls = tru
- If 'False _tru fls = fls
+ If 'True tru fls = tru
+ If 'False tru fls = fls
-- | Type-level "and"
type family a && b where
- 'False && _a = 'False
+ 'False && a = 'False
'True && a = a
- _a && 'False = 'False
+ a && 'False = 'False
a && 'True = a
a && a = a
infixr 3 &&
@@ -43,9 +43,9 @@ infixr 3 &&
-- | Type-level "or"
type family a || b where
'False || a = a
- 'True || _a = 'True
+ 'True || a = 'True
a || 'False = a
- _a || 'True = 'True
+ a || 'True = 'True
a || a = a
infixr 2 ||
diff --git a/libraries/base/Data/Type/Equality.hs b/libraries/base/Data/Type/Equality.hs
index a72e268a71..75d2a6ca7e 100644
--- a/libraries/base/Data/Type/Equality.hs
+++ b/libraries/base/Data/Type/Equality.hs
@@ -205,37 +205,37 @@ families.
-- all of the following closed type families are local to this module
type family EqStar (a :: *) (b :: *) where
- EqStar _a _a = 'True
- EqStar _a _b = 'False
+ EqStar a a = 'True
+ EqStar a b = 'False
-- This looks dangerous, but it isn't. This allows == to be defined
-- over arbitrary type constructors.
type family EqArrow (a :: k1 -> k2) (b :: k1 -> k2) where
- EqArrow _a _a = 'True
- EqArrow _a _b = 'False
+ EqArrow a a = 'True
+ EqArrow a b = 'False
type family EqBool a b where
EqBool 'True 'True = 'True
EqBool 'False 'False = 'True
- EqBool _a _b = 'False
+ EqBool a b = 'False
type family EqOrdering a b where
EqOrdering 'LT 'LT = 'True
EqOrdering 'EQ 'EQ = 'True
EqOrdering 'GT 'GT = 'True
- EqOrdering _a _b = 'False
+ EqOrdering a b = 'False
type EqUnit (a :: ()) (b :: ()) = 'True
type family EqList a b where
EqList '[] '[] = 'True
EqList (h1 ': t1) (h2 ': t2) = (h1 == h2) && (t1 == t2)
- EqList _a _b = 'False
+ EqList a b = 'False
type family EqMaybe a b where
EqMaybe 'Nothing 'Nothing = 'True
EqMaybe ('Just x) ('Just y) = x == y
- EqMaybe _a _b = 'False
+ EqMaybe a b = 'False
type family Eq2 a b where
Eq2 '(a1, b1) '(a2, b2) = a1 == a2 && b1 == b2
diff --git a/libraries/base/GHC/Generics.hs b/libraries/base/GHC/Generics.hs
index 3ac4d5c500..4cadf437e5 100644
--- a/libraries/base/GHC/Generics.hs
+++ b/libraries/base/GHC/Generics.hs
@@ -763,27 +763,27 @@ newtype (:.:) f (g :: * -> *) (p :: *) = Comp1 { unComp1 :: f (g p) }
data family URec (a :: *) (p :: *)
-- | Used for marking occurrences of 'Addr#'
-data instance URec (Ptr ()) _p = UAddr { uAddr# :: Addr# }
+data instance URec (Ptr ()) p = UAddr { uAddr# :: Addr# }
deriving (Eq, Ord, Generic)
-- | Used for marking occurrences of 'Char#'
-data instance URec Char _p = UChar { uChar# :: Char# }
+data instance URec Char p = UChar { uChar# :: Char# }
deriving (Eq, Ord, Show, Generic)
-- | Used for marking occurrences of 'Double#'
-data instance URec Double _p = UDouble { uDouble# :: Double# }
+data instance URec Double p = UDouble { uDouble# :: Double# }
deriving (Eq, Ord, Show, Generic)
-- | Used for marking occurrences of 'Float#'
-data instance URec Float _p = UFloat { uFloat# :: Float# }
+data instance URec Float p = UFloat { uFloat# :: Float# }
deriving (Eq, Ord, Show, Generic)
-- | Used for marking occurrences of 'Int#'
-data instance URec Int _p = UInt { uInt# :: Int# }
+data instance URec Int p = UInt { uInt# :: Int# }
deriving (Eq, Ord, Show, Generic)
-- | Used for marking occurrences of 'Word#'
-data instance URec Word _p = UWord { uWord# :: Word# }
+data instance URec Word p = UWord { uWord# :: Word# }
deriving (Eq, Ord, Show, Generic)
-- | Type synonym for 'URec': 'Addr#'
@@ -1051,7 +1051,7 @@ class (kparam ~ 'KProxy) => SingKind (kparam :: KProxy k) where
fromSing :: Sing (a :: k) -> DemoteRep kparam
-- Singleton symbols
-data instance Sing (_s :: Symbol) where
+data instance Sing (s :: Symbol) where
SSym :: KnownSymbol s => Sing s
instance KnownSymbol a => SingI a where sing = SSym
@@ -1061,7 +1061,7 @@ instance SingKind ('KProxy :: KProxy Symbol) where
fromSing (SSym :: Sing s) = symbolVal (Proxy :: Proxy s)
-- Singleton booleans
-data instance Sing (_a :: Bool) where
+data instance Sing (a :: Bool) where
STrue :: Sing 'True
SFalse :: Sing 'False
@@ -1074,7 +1074,7 @@ instance SingKind ('KProxy :: KProxy Bool) where
fromSing SFalse = False
-- Singleton Maybe
-data instance Sing (_b :: Maybe _a) where
+data instance Sing (b :: Maybe a) where
SNothing :: Sing 'Nothing
SJust :: Sing a -> Sing ('Just a)
@@ -1089,7 +1089,7 @@ instance SingKind ('KProxy :: KProxy a) =>
fromSing (SJust a) = Just (fromSing a)
-- Singleton Fixity
-data instance Sing (_a :: FixityI) where
+data instance Sing (a :: FixityI) where
SPrefix :: Sing 'PrefixI
SInfix :: Sing a -> Integer -> Sing ('InfixI a n)
@@ -1103,7 +1103,7 @@ instance SingKind ('KProxy :: KProxy FixityI) where
fromSing (SInfix a n) = Infix (fromSing a) (I# (integerToInt n))
-- Singleton Associativity
-data instance Sing (_a :: Associativity) where
+data instance Sing (a :: Associativity) where
SLeftAssociative :: Sing 'LeftAssociative
SRightAssociative :: Sing 'RightAssociative
SNotAssociative :: Sing 'NotAssociative
@@ -1119,7 +1119,7 @@ instance SingKind ('KProxy :: KProxy Associativity) where
fromSing SNotAssociative = NotAssociative
-- Singleton SourceUnpackedness
-data instance Sing (_a :: SourceUnpackedness) where
+data instance Sing (a :: SourceUnpackedness) where
SNoSourceUnpackedness :: Sing 'NoSourceUnpackedness
SSourceNoUnpack :: Sing 'SourceNoUnpack
SSourceUnpack :: Sing 'SourceUnpack
@@ -1135,7 +1135,7 @@ instance SingKind ('KProxy :: KProxy SourceUnpackedness) where
fromSing SSourceUnpack = SourceUnpack
-- Singleton SourceStrictness
-data instance Sing (_a :: SourceStrictness) where
+data instance Sing (a :: SourceStrictness) where
SNoSourceStrictness :: Sing 'NoSourceStrictness
SSourceLazy :: Sing 'SourceLazy
SSourceStrict :: Sing 'SourceStrict
@@ -1151,7 +1151,7 @@ instance SingKind ('KProxy :: KProxy SourceStrictness) where
fromSing SSourceStrict = SourceStrict
-- Singleton DecidedStrictness
-data instance Sing (_a :: DecidedStrictness) where
+data instance Sing (a :: DecidedStrictness) where
SDecidedLazy :: Sing 'DecidedLazy
SDecidedStrict :: Sing 'DecidedStrict
SDecidedUnpack :: Sing 'DecidedUnpack
diff --git a/libraries/base/GHC/TypeLits.hs b/libraries/base/GHC/TypeLits.hs
index b32721d63c..a51ba910e0 100644
--- a/libraries/base/GHC/TypeLits.hs
+++ b/libraries/base/GHC/TypeLits.hs
@@ -146,13 +146,13 @@ instance Read SomeSymbol where
readsPrec p xs = [ (someSymbolVal a, ys) | (a,ys) <- readsPrec p xs ]
type family EqNat (a :: Nat) (b :: Nat) where
- EqNat _a _a = 'True
- EqNat _a _b = 'False
+ EqNat a a = 'True
+ EqNat a b = 'False
type instance a == b = EqNat a b
type family EqSymbol (a :: Symbol) (b :: Symbol) where
- EqSymbol _a _a = 'True
- EqSymbol _a _b = 'False
+ EqSymbol a a = 'True
+ EqSymbol a b = 'False
type instance a == b = EqSymbol a b
--------------------------------------------------------------------------------
diff --git a/testsuite/tests/determinism/should_compile/determ004.hs b/testsuite/tests/determinism/should_compile/determ004.hs
index 88fe88a770..c74f8d02d8 100644
--- a/testsuite/tests/determinism/should_compile/determ004.hs
+++ b/testsuite/tests/determinism/should_compile/determ004.hs
@@ -225,7 +225,7 @@ data TyFun (a :: *) (b :: *)
type family Apply (f :: TyFun k1 k2 -> *) (x :: k1) :: k2
-data instance Sing (f :: TyFun _k1 _k2 -> *) =
+data instance Sing (f :: TyFun k1 k2 -> *) =
SLambda { applySing :: forall t. Sing t -> Sing (Apply f t) }
type SingFunction1 f = forall t. Sing t -> Sing (Apply f t)
@@ -273,9 +273,9 @@ type family Foldr1 (a_afe5 :: TyFun a_afdP (TyFun a_afdP a_afdP
-> *)
-> *)
(a_afe6 :: [a_afdP]) :: a_afdP where
- Foldr1 _z_afe7 '[x_afe8] = x_afe8
+ Foldr1 z_afe7 '[x_afe8] = x_afe8
Foldr1 f_afe9 ((:) x_afea ((:) wild_1627448474_afeb wild_1627448476_afec)) = Apply (Apply f_afe9 x_afea) (Apply (Apply Foldr1Sym0 f_afe9) (Let1627448493XsSym4 f_afe9 x_afea wild_1627448474_afeb wild_1627448476_afec))
- Foldr1 _z_afew '[] = Apply ErrorSym0 "Data.Singletons.List.foldr1: empty list"
+ Foldr1 z_afew '[] = Apply ErrorSym0 "Data.Singletons.List.foldr1: empty list"
sFoldr1 ::
forall (x :: TyFun a_afdP (TyFun a_afdP a_afdP -> *) -> *)
diff --git a/testsuite/tests/indexed-types/should_compile/all.T b/testsuite/tests/indexed-types/should_compile/all.T
index 28ea8bd624..9fece9c1c4 100644
--- a/testsuite/tests/indexed-types/should_compile/all.T
+++ b/testsuite/tests/indexed-types/should_compile/all.T
@@ -268,8 +268,8 @@ test('T10931', normal, compile, [''])
test('T11187', normal, compile, [''])
test('T11067', normal, compile, [''])
test('T10318', normal, compile, [''])
-test('UnusedTyVarWarnings', normal, compile, ['-W'])
-test('UnusedTyVarWarningsNamedWCs', normal, compile, ['-W'])
+test('UnusedTyVarWarnings', normal, compile, ['-Wunused-type-patterns'])
+test('UnusedTyVarWarningsNamedWCs', normal, compile, ['-Wunused-type-patterns'])
test('T11408', normal, compile, [''])
test('T11361', normal, compile, [''])
test('T11361a', normal, compile_fail, [''])
diff --git a/testsuite/tests/simplCore/should_compile/T10689a.hs b/testsuite/tests/simplCore/should_compile/T10689a.hs
index 477d80cb14..5b21b42db7 100644
--- a/testsuite/tests/simplCore/should_compile/T10689a.hs
+++ b/testsuite/tests/simplCore/should_compile/T10689a.hs
@@ -76,9 +76,9 @@ type family Foldr1 (a_afe5 :: TyFun a_afdP (TyFun a_afdP a_afdP
-> *)
-> *)
(a_afe6 :: [a_afdP]) :: a_afdP where
- Foldr1 _z_afe7 '[x_afe8] = x_afe8
+ Foldr1 z_afe7 '[x_afe8] = x_afe8
Foldr1 f_afe9 ((:) x_afea ((:) wild_1627448474_afeb wild_1627448476_afec)) = Apply (Apply f_afe9 x_afea) (Apply (Apply Foldr1Sym0 f_afe9) (Let1627448493XsSym4 f_afe9 x_afea wild_1627448474_afeb wild_1627448476_afec))
- Foldr1 _z_afew '[] = Apply ErrorSym0 "Data.Singletons.List.foldr1: empty list"
+ Foldr1 z_afew '[] = Apply ErrorSym0 "Data.Singletons.List.foldr1: empty list"
sFoldr1 ::
forall (x :: TyFun a_afdP (TyFun a_afdP a_afdP -> *) -> *)
diff --git a/utils/mkUserGuidePart/Options/Warnings.hs b/utils/mkUserGuidePart/Options/Warnings.hs
index 256d01f9fa..3fa9bf087e 100644
--- a/utils/mkUserGuidePart/Options/Warnings.hs
+++ b/utils/mkUserGuidePart/Options/Warnings.hs
@@ -291,6 +291,18 @@ warningsOptions =
, flagType = DynamicFlag
, flagReverse = "-Wno-unused-matches"
}
+ , flag { flagName = "-Wunused-foralls"
+ , flagDescription = "warn about type variables in user-written "++
+ "``forall``\\s that are unused"
+ , flagType = DynamicFlag
+ , flagReverse = "-Wno-unused-foralls"
+ }
+ , flag { flagName = "-Wunused-type-variables"
+ , flagDescription = "warn about variables in type family or data "++
+ "family instances that are unused"
+ , flagType = DynamicFlag
+ , flagReverse = "-Wno-unused-type-variables"
+ }
, flag { flagName = "-Wunused-do-bind"
, flagDescription =
"warn about do bindings that appear to throw away values of types "++
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