Safe Haskell	None
Language	GHC2021

GHC.Core.InstEnv

Synopsis

type DFunId = Id
type InstMatch = (ClsInst, [DFunInstType])
type ClsInstLookupResult = ([InstMatch], PotentialUnifiers, [InstMatch])
type Canonical = Bool
data PotentialUnifiers
- = NoUnifiers Canonical
- | OneOrMoreUnifiers (NonEmpty ClsInst)
getPotentialUnifiers :: PotentialUnifiers -> [ClsInst]
nullUnifiers :: PotentialUnifiers -> Bool
data OverlapFlag = OverlapFlag {
- overlapMode :: OverlapMode
- isSafeOverlap :: Bool
}
data OverlapMode
- = NoOverlap SourceText
- | Overlappable SourceText
- | Overlapping SourceText
- | Overlaps SourceText
- | Incoherent SourceText
- | NonCanonical SourceText
setOverlapModeMaybe :: OverlapFlag -> Maybe OverlapMode -> OverlapFlag
data ClsInst = ClsInst {
- is_cls_nm :: Name
- is_tcs :: [RoughMatchTc]
- is_dfun_name :: Name
- is_tvs :: [TyVar]
- is_cls :: Class
- is_tys :: [Type]
- is_dfun :: DFunId
- is_flag :: OverlapFlag
- is_orphan :: IsOrphan
- is_warn :: Maybe (WarningTxt GhcRn)
}
type DFunInstType = Maybe Type
pprInstance :: ClsInst -> SDoc
pprInstanceHdr :: ClsInst -> SDoc
pprDFunId :: DFunId -> SDoc
pprInstances :: [ClsInst] -> SDoc
instanceWarning :: ClsInst -> Maybe (WarningTxt GhcRn)
instanceHead :: ClsInst -> ([TyVar], Class, [Type])
instanceSig :: ClsInst -> ([TyVar], [Type], Class, [Type])
mkLocalClsInst :: DFunId -> OverlapFlag -> [TyVar] -> Class -> [Type] -> Maybe (WarningTxt GhcRn) -> ClsInst
mkImportedClsInst :: Name -> [RoughMatchTc] -> Name -> DFunId -> OverlapFlag -> IsOrphan -> Maybe (WarningTxt GhcRn) -> ClsInst
instanceDFunId :: ClsInst -> DFunId
updateClsInstDFuns :: (DFunId -> DFunId) -> InstEnv -> InstEnv
updateClsInstDFun :: (DFunId -> DFunId) -> ClsInst -> ClsInst
fuzzyClsInstCmp :: ClsInst -> ClsInst -> Ordering
orphNamesOfClsInst :: ClsInst -> NameSet
data InstEnvs = InstEnvs {
- ie_global :: InstEnv
- ie_local :: InstEnv
- ie_visible :: VisibleOrphanModules
}
type VisibleOrphanModules = ModuleSet
data InstEnv
data LookupInstanceErrReason
- = LookupInstErrNotExact
- | LookupInstErrFlexiVar
- | LookupInstErrNotFound
mkInstEnv :: [ClsInst] -> InstEnv
emptyInstEnv :: InstEnv
unionInstEnv :: InstEnv -> InstEnv -> InstEnv
extendInstEnv :: InstEnv -> ClsInst -> InstEnv
filterInstEnv :: (ClsInst -> Bool) -> InstEnv -> InstEnv
deleteFromInstEnv :: InstEnv -> ClsInst -> InstEnv
deleteDFunFromInstEnv :: InstEnv -> DFunId -> InstEnv
anyInstEnv :: (ClsInst -> Bool) -> InstEnv -> Bool
identicalClsInstHead :: ClsInst -> ClsInst -> Bool
extendInstEnvList :: InstEnv -> [ClsInst] -> InstEnv
lookupUniqueInstEnv :: InstEnvs -> Class -> [Type] -> Either LookupInstanceErrReason (ClsInst, [Type])
lookupInstEnv :: Bool -> InstEnvs -> Class -> [Type] -> ClsInstLookupResult
instEnvElts :: InstEnv -> [ClsInst]
instEnvClasses :: InstEnv -> UniqDSet Class
mapInstEnv :: (ClsInst -> ClsInst) -> InstEnv -> InstEnv
memberInstEnv :: InstEnv -> ClsInst -> Bool
instIsVisible :: VisibleOrphanModules -> ClsInst -> Bool
classInstances :: InstEnvs -> Class -> [ClsInst]
instanceBindFun :: BindFun
classNameInstances :: InstEnvs -> Name -> [ClsInst]
instanceCantMatch :: [RoughMatchTc] -> [RoughMatchTc] -> Bool
roughMatchTcs :: [Type] -> [RoughMatchTc]
isOverlappable :: ClsInst -> Bool
isOverlapping :: ClsInst -> Bool
isIncoherent :: ClsInst -> Bool

Documentation

type DFunId = Id Source #

Dictionary Function Identifier

type InstMatch = (ClsInst, [DFunInstType]) Source #

type ClsInstLookupResult = ([InstMatch], PotentialUnifiers, [InstMatch]) Source #

type Canonical = Bool Source #

data PotentialUnifiers Source #

Constructors

NoUnifiers Canonical
OneOrMoreUnifiers (NonEmpty ClsInst)

Instances

Instances details

Outputable PotentialUnifiers Source #
Instance details Defined in GHC.Core.InstEnv Methods ppr :: PotentialUnifiers -> SDoc Source #
Semigroup PotentialUnifiers Source #
Instance details Defined in GHC.Core.InstEnv Methods (<>) :: PotentialUnifiers -> PotentialUnifiers -> PotentialUnifiers # sconcat :: NonEmpty PotentialUnifiers -> PotentialUnifiers # stimes :: Integral b => b -> PotentialUnifiers -> PotentialUnifiers #

getPotentialUnifiers :: PotentialUnifiers -> [ClsInst] Source #

nullUnifiers :: PotentialUnifiers -> Bool Source #

data OverlapFlag Source #

The semantics allowed for overlapping instances for a particular instance. See Note [Safe Haskell isSafeOverlap] in GHC.Core.InstEnv for a explanation of the isSafeOverlap field.

AnnKeywordId : AnnOpen '{-# OVERLAPPABLE' or '{-# OVERLAPPING' or '{-# OVERLAPS' or '{-# INCOHERENT', AnnClose `#-}`,

Constructors

OverlapFlag
Fields overlapMode :: OverlapMode isSafeOverlap :: Bool

Instances

Instances details

Binary OverlapFlag Source #
Instance details Defined in GHC.Types.Basic Methods put_ :: BinHandle -> OverlapFlag -> IO () Source # put :: BinHandle -> OverlapFlag -> IO (Bin OverlapFlag) Source # get :: BinHandle -> IO OverlapFlag Source #
Outputable OverlapFlag Source #
Instance details Defined in GHC.Types.Basic Methods ppr :: OverlapFlag -> SDoc Source #
Data OverlapFlag Source #
Instance details Defined in GHC.Types.Basic Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> OverlapFlag -> c OverlapFlag # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c OverlapFlag # toConstr :: OverlapFlag -> Constr # dataTypeOf :: OverlapFlag -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c OverlapFlag) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c OverlapFlag) # gmapT :: (forall b. Data b => b -> b) -> OverlapFlag -> OverlapFlag # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> OverlapFlag -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> OverlapFlag -> r # gmapQ :: (forall d. Data d => d -> u) -> OverlapFlag -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> OverlapFlag -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> OverlapFlag -> m OverlapFlag # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> OverlapFlag -> m OverlapFlag # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> OverlapFlag -> m OverlapFlag #
Eq OverlapFlag Source #
Instance details Defined in GHC.Types.Basic Methods (==) :: OverlapFlag -> OverlapFlag -> Bool # (/=) :: OverlapFlag -> OverlapFlag -> Bool #

data OverlapMode Source #

Constructors

NoOverlap SourceText	This instance must not overlap another `NoOverlap` instance. However, it may be overlapped by `Overlapping` instances, and it may overlap `Overlappable` instances.
Overlappable SourceText	Silently ignore this instance if you find a more specific one that matches the constraint you are trying to resolve Example: constraint (Foo [Int]) instance Foo [Int] instance {-# OVERLAPPABLE #-} Foo [a] Since the second instance has the Overlappable flag, the first instance will be chosen (otherwise its ambiguous which to choose)
Overlapping SourceText	Silently ignore any more general instances that may be used to solve the constraint. Example: constraint (Foo [Int]) instance {-# OVERLAPPING #-} Foo [Int] instance Foo [a] Since the first instance has the Overlapping flag, the second---more general---instance will be ignored (otherwise it is ambiguous which to choose)
Overlaps SourceText	Equivalent to having both `Overlapping` and `Overlappable` flags.
Incoherent SourceText	Behave like Overlappable and Overlapping, and in addition pick an arbitrary one if there are multiple matching candidates, and don't worry about later instantiation Example: constraint (Foo [b]) instance {-# INCOHERENT -} Foo [Int] instance Foo [a] Without the Incoherent flag, we'd complain that instantiating `b` would change which instance was chosen. See also Note [Incoherent instances] in GHC.Core.InstEnv
NonCanonical SourceText	Behave like Incoherent, but the instance choice is observable by the program behaviour. See Note [Coherence and specialisation: overview]. We don't have surface syntax for the distinction between Incoherent and NonCanonical instances; instead, the flag `-f{no-}specialise-incoherents` (on by default) controls whether `INCOHERENT` instances are regarded as Incoherent or NonCanonical.

Instances

Instances details

Binary OverlapMode Source #
Instance details Defined in GHC.Types.Basic Methods put_ :: BinHandle -> OverlapMode -> IO () Source # put :: BinHandle -> OverlapMode -> IO (Bin OverlapMode) Source # get :: BinHandle -> IO OverlapMode Source #
Outputable OverlapMode Source #
Instance details Defined in GHC.Types.Basic Methods ppr :: OverlapMode -> SDoc Source #
Data OverlapMode Source #
Instance details Defined in GHC.Types.Basic Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> OverlapMode -> c OverlapMode # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c OverlapMode # toConstr :: OverlapMode -> Constr # dataTypeOf :: OverlapMode -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c OverlapMode) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c OverlapMode) # gmapT :: (forall b. Data b => b -> b) -> OverlapMode -> OverlapMode # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> OverlapMode -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> OverlapMode -> r # gmapQ :: (forall d. Data d => d -> u) -> OverlapMode -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> OverlapMode -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> OverlapMode -> m OverlapMode # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> OverlapMode -> m OverlapMode # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> OverlapMode -> m OverlapMode #
Eq OverlapMode Source #
Instance details Defined in GHC.Types.Basic Methods (==) :: OverlapMode -> OverlapMode -> Bool # (/=) :: OverlapMode -> OverlapMode -> Bool #
type Anno OverlapMode Source #
Instance details Defined in GHC.Hs.Decls type Anno OverlapMode = SrcSpanAnnP
type Anno OverlapMode Source #
Instance details Defined in GHC.Hs.Decls type Anno OverlapMode = SrcSpanAnnP

setOverlapModeMaybe :: OverlapFlag -> Maybe OverlapMode -> OverlapFlag Source #

data ClsInst Source #

A type-class instance. Note that there is some tricky laziness at work here. See Note [ClsInst laziness and the rough-match fields] for more details.

Constructors

ClsInst

Fields

is_cls_nm :: Name
Class name
is_tcs :: [RoughMatchTc]
Top of type args The class itself is always the first element of this list
is_dfun_name :: Name
is_dfun_name = idName . is_dfun.
We use is_dfun_name for the visibility check, instIsVisible, which needs to know the Module which the dictionary is defined in. However, we cannot use the Module attached to is_dfun since doing so would mean we would potentially pull in an entire interface file unnecessarily. This was the cause of #12367.
is_tvs :: [TyVar]
is_cls :: Class
is_tys :: [Type]
is_dfun :: DFunId
is_flag :: OverlapFlag
is_orphan :: IsOrphan
is_warn :: Maybe (WarningTxt GhcRn)

Instances

Instances details

NamedThing ClsInst Source #
Instance details Defined in GHC.Core.InstEnv Methods getOccName :: ClsInst -> OccName Source # getName :: ClsInst -> Name Source #
Outputable ClsInst Source #
Instance details Defined in GHC.Core.InstEnv Methods ppr :: ClsInst -> SDoc Source #
Data ClsInst Source #
Instance details Defined in GHC.Core.InstEnv Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> ClsInst -> c ClsInst # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c ClsInst # toConstr :: ClsInst -> Constr # dataTypeOf :: ClsInst -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c ClsInst) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c ClsInst) # gmapT :: (forall b. Data b => b -> b) -> ClsInst -> ClsInst # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> ClsInst -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> ClsInst -> r # gmapQ :: (forall d. Data d => d -> u) -> ClsInst -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> ClsInst -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> ClsInst -> m ClsInst # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> ClsInst -> m ClsInst # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> ClsInst -> m ClsInst #

type DFunInstType = Maybe Type Source #

pprInstance :: ClsInst -> SDoc Source #

pprInstanceHdr :: ClsInst -> SDoc Source #

pprDFunId :: DFunId -> SDoc Source #

pprInstances :: [ClsInst] -> SDoc Source #

instanceWarning :: ClsInst -> Maybe (WarningTxt GhcRn) Source #

instanceHead :: ClsInst -> ([TyVar], Class, [Type]) Source #

instanceSig :: ClsInst -> ([TyVar], [Type], Class, [Type]) Source #

mkLocalClsInst :: DFunId -> OverlapFlag -> [TyVar] -> Class -> [Type] -> Maybe (WarningTxt GhcRn) -> ClsInst Source #

mkImportedClsInst Source #

Arguments

:: Name	the name of the class
-> [RoughMatchTc]	the rough match signature of the instance
-> Name	the `Name` of the dictionary binding
-> DFunId	the `Id` of the dictionary.
-> OverlapFlag	may this instance overlap?
-> IsOrphan	is this instance an orphan?
-> Maybe (WarningTxt GhcRn)	warning emitted when solved
-> ClsInst

instanceDFunId :: ClsInst -> DFunId Source #

updateClsInstDFuns :: (DFunId -> DFunId) -> InstEnv -> InstEnv Source #

updateClsInstDFun :: (DFunId -> DFunId) -> ClsInst -> ClsInst Source #

fuzzyClsInstCmp :: ClsInst -> ClsInst -> Ordering Source #

A fuzzy comparison function for class instances, intended for sorting instances before displaying them to the user.

orphNamesOfClsInst :: ClsInst -> NameSet Source #

Collects the names of concrete types and type constructors that make up the head of a class instance. For instance, given `class Foo a b`:

`instance Foo (Either (Maybe Int) a) Bool` would yield [Either, Maybe, Int, Bool]

Used in the implementation of ":info" in GHCi.

The tcSplitSigmaTy is because of instance Foo a => Baz T where ... The decl is an orphan if Baz and T are both not locally defined, even if Foo *is* locally defined

data InstEnvs Source #

InstEnvs represents the combination of the global type class instance environment, the local type class instance environment, and the set of transitively reachable orphan modules (according to what modules have been directly imported) used to test orphan instance visibility.

Constructors

InstEnvs
Fields ie_global :: InstEnv ie_local :: InstEnv ie_visible :: VisibleOrphanModules

type VisibleOrphanModules = ModuleSet Source #

Set of visible orphan modules, according to what modules have been directly imported. This is based off of the dep_orphs field, which records transitively reachable orphan modules (modules that define orphan instances).

data InstEnv Source #

Instances

Instances details

Outputable InstEnv Source #
Instance details Defined in GHC.Core.InstEnv Methods ppr :: InstEnv -> SDoc Source #

data LookupInstanceErrReason Source #

Why a particular typeclass application couldn't be looked up.

Constructors

LookupInstErrNotExact	Tyvars aren't an exact match.
LookupInstErrFlexiVar	One of the tyvars is flexible.
LookupInstErrNotFound	No matching instance was found.

Instances

Instances details

Generic LookupInstanceErrReason Source #

Instance details

Defined in GHC.Core.InstEnv

Associated Types

type Rep LookupInstanceErrReason

Instance details

Defined in GHC.Core.InstEnv

type Rep LookupInstanceErrReason = D1 ('MetaData "LookupInstanceErrReason" "GHC.Core.InstEnv" "ghc-9.10.1-25ec" 'False) (C1 ('MetaCons "LookupInstErrNotExact" 'PrefixI 'False) (U1 :: Type -> Type) :+: (C1 ('MetaCons "LookupInstErrFlexiVar" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "LookupInstErrNotFound" 'PrefixI 'False) (U1 :: Type -> Type)))

Methods

from :: LookupInstanceErrReason -> Rep LookupInstanceErrReason x #

to :: Rep LookupInstanceErrReason x -> LookupInstanceErrReason #

type Rep LookupInstanceErrReason Source #

Instance details

Defined in GHC.Core.InstEnv

type Rep LookupInstanceErrReason = D1 ('MetaData "LookupInstanceErrReason" "GHC.Core.InstEnv" "ghc-9.10.1-25ec" 'False) (C1 ('MetaCons "LookupInstErrNotExact" 'PrefixI 'False) (U1 :: Type -> Type) :+: (C1 ('MetaCons "LookupInstErrFlexiVar" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "LookupInstErrNotFound" 'PrefixI 'False) (U1 :: Type -> Type)))

mkInstEnv :: [ClsInst] -> InstEnv Source #

emptyInstEnv :: InstEnv Source #

unionInstEnv :: InstEnv -> InstEnv -> InstEnv Source #

Makes no particular effort to detect conflicts.

extendInstEnv :: InstEnv -> ClsInst -> InstEnv Source #

filterInstEnv :: (ClsInst -> Bool) -> InstEnv -> InstEnv Source #

deleteFromInstEnv :: InstEnv -> ClsInst -> InstEnv Source #

deleteDFunFromInstEnv :: InstEnv -> DFunId -> InstEnv Source #

anyInstEnv :: (ClsInst -> Bool) -> InstEnv -> Bool Source #

identicalClsInstHead :: ClsInst -> ClsInst -> Bool Source #

True when when the instance heads are the same e.g. both are Eq [(a,b)] Used for overriding in GHCi Obviously should be insensitive to alpha-renaming

extendInstEnvList :: InstEnv -> [ClsInst] -> InstEnv Source #

lookupUniqueInstEnv :: InstEnvs -> Class -> [Type] -> Either LookupInstanceErrReason (ClsInst, [Type]) Source #

Look up an instance in the given instance environment. The given class application must match exactly one instance and the match may not contain any flexi type variables. If the lookup is unsuccessful, yield 'Left errorMessage'.

lookupInstEnv :: Bool -> InstEnvs -> Class -> [Type] -> ClsInstLookupResult Source #

See Note [Rules for instance lookup] ^ See Note [Safe Haskell Overlapping Instances] in GHC.Tc.Solver ^ See Note [Safe Haskell Overlapping Instances Implementation] in GHC.Tc.Solver

instEnvElts :: InstEnv -> [ClsInst] Source #

instEnvClasses :: InstEnv -> UniqDSet Class Source #

mapInstEnv :: (ClsInst -> ClsInst) -> InstEnv -> InstEnv Source #

memberInstEnv :: InstEnv -> ClsInst -> Bool Source #

Checks for an exact match of ClsInst in the instance environment. We use this when we do signature checking in GHC.Tc.Module

instIsVisible :: VisibleOrphanModules -> ClsInst -> Bool Source #

Test if an instance is visible, by checking that its origin module is in VisibleOrphanModules. See Note [Instance lookup and orphan instances]

classInstances :: InstEnvs -> Class -> [ClsInst] Source #

instanceBindFun :: BindFun Source #

classNameInstances :: InstEnvs -> Name -> [ClsInst] Source #

instanceCantMatch :: [RoughMatchTc] -> [RoughMatchTc] -> Bool Source #

roughMatchTcs :: [Type] -> [RoughMatchTc] Source #

isOverlappable :: ClsInst -> Bool Source #

isOverlapping :: ClsInst -> Bool Source #

isIncoherent :: ClsInst -> Bool Source #