GHC.Tc.Utils.TcType

ghc-lib-parser-9.14.1.20251220: The GHC API, decoupled from GHC versions

Safe Haskell | Ignore
Language | GHC2021

GHC.Tc.Utils.TcType

Contents

- Finding type instances
- Finding "exact" (non-dead) type variables

Description

Types used in the typechecker

This module provides the Type interface for front-end parts of the compiler. These parts

- treat "source types" as opaque: newtypes, and predicates are meaningful.
- look through usage types

Synopsis

- type TcType = Type
- type TcSigmaType = TcType
- type TcTypeFRR = TcType
- type TcSigmaTypeFRR = TcSigmaType
- type TcRhoType = TcType
- type TcRhoTypeFRR = TcRhoType
- type TcTauType = TcType
- type TcPredType = PredType
- type TcThetaType = ThetaType
- type TcTyVar = Var
- type TcTyVarSet = TyVarSet
- type TcDTyVarSet = DTyVarSet
- type TcTyCoVarSet = TyCoVarSet
- type TcDTyCoVarSet = DTyCoVarSet
- type TcKind = Kind
- type TcCoVar = CoVar
- type TcTyCoVar = Var
- type TcTyVarBinder = TyVarBinder
- type TcInvisTVBinder = InvisTVBinder
- type TcReqTVBinder = ReqTVBinder
- type TcTyCon = TyCon
- type MonoTcTyCon = TcTyCon
- type PolyTcTyCon = TcTyCon
- type TcTyConBinder = TyConBinder
- type KnotTied (ty :: k) = ty
- data ExpType
  - = Check TcType
  - | Infer !InferResult
- type ExpKind = ExpType
- data InferResult = IR {
  - ir_uniq :: Unique
  - ir_lvl :: TcLevel
  - ir_frr :: InferFRRFlag
  - ir_inst :: InferInstFlag
  - ir_ref :: IORef (Maybe TcType)
  }
- data InferInstFlag
  - = IIF_Sigma
  - | IIF_ShallowRho
  - | IIF_DeepRho
- data InferFRRFlag
  - = IFRR_Check FixedRuntimeRepContext
  - | IFRR_Any
- type ExpTypeFRR = ExpType
- type ExpSigmaType = ExpType
- type ExpSigmaTypeFRR = ExpTypeFRR
- type ExpRhoType = ExpType
- type ExpRhoTypeFRR = ExpTypeFRR
- mkCheckExpType :: TcType -> ExpType
- checkingExpType_maybe :: ExpType -> Maybe TcType
- checkingExpType :: ExpType -> TcType
- data ExpPatType
  - = ExpFunPatTy (Scaled ExpSigmaTypeFRR)
  - | ExpForAllPatTy ForAllTyBinder
- mkCheckExpFunPatTy :: Scaled TcType -> ExpPatType
- mkInvisExpPatType :: InvisTyBinder -> ExpPatType
- isVisibleExpPatType :: ExpPatType -> Bool
- isExpFunPatType :: ExpPatType -> Bool
- data SyntaxOpType
  - = SynAny
  - | SynRho
  - | SynList
  - | SynFun SyntaxOpType SyntaxOpType
  - | SynType ExpType
- synKnownType :: TcType -> SyntaxOpType
- mkSynFunTys :: [SyntaxOpType] -> ExpType -> SyntaxOpType
- data TcLevel
  - = TcLevel !Int
  - | QLInstVar
- topTcLevel :: TcLevel
- pushTcLevel :: TcLevel -> TcLevel
- isTopTcLevel :: TcLevel -> Bool
- strictlyDeeperThan :: TcLevel -> TcLevel -> Bool
- deeperThanOrSame :: TcLevel -> TcLevel -> Bool
- sameDepthAs :: TcLevel -> TcLevel -> Bool
- tcTypeLevel :: TcType -> TcLevel
- tcTyVarLevel :: TcTyVar -> TcLevel
- maxTcLevel :: TcLevel -> TcLevel -> TcLevel
- minTcLevel :: TcLevel -> TcLevel -> TcLevel
- data TcTyVarDetails
  - = SkolemTv SkolemInfo TcLevel Bool
  - | RuntimeUnk
  - | MetaTv {
    - mtv_info :: MetaInfo
    - mtv_ref :: IORef MetaDetails
    - mtv_tclvl :: TcLevel
    }
- pprTcTyVarDetails :: TcTyVarDetails -> SDoc
- vanillaSkolemTvUnk :: HasDebugCallStack => TcTyVarDetails
- data MetaDetails
  - = Flexi
  - | Indirect TcType
- data MetaInfo
  - = TauTv
  - | TyVarTv
  - | RuntimeUnkTv
  - | CycleBreakerTv
  - | ConcreteTv ConcreteTvOrigin
- skolemSkolInfo :: TcTyVar -> SkolemInfo
- isImmutableTyVar :: TyVar -> Bool
- isSkolemTyVar :: TcTyVar -> Bool
- isMetaTyVar :: TcTyVar -> Bool
- isMetaTyVarTy :: TcType -> Bool
- isTyVarTy :: Type -> Bool
- tcIsTcTyVar :: TcTyVar -> Bool
- isTyVarTyVar :: Var -> Bool
- isOverlappableTyVar :: TcTyVar -> Bool
- isTyConableTyVar :: TcTyVar -> Bool
- data ConcreteTvOrigin = ConcreteFRR FixedRuntimeRepOrigin
- isConcreteTyVar_maybe :: TcTyVar -> Maybe ConcreteTvOrigin
- isConcreteTyVar :: TcTyVar -> Bool
- isConcreteTyVarTy :: TcType -> Bool
- isConcreteTyVarTy_maybe :: TcType -> Maybe (TcTyVar, ConcreteTvOrigin)
- concreteInfo_maybe :: MetaInfo -> Maybe ConcreteTvOrigin
- type ConcreteTyVars = NameEnv ConcreteTvOrigin
- noConcreteTyVars :: ConcreteTyVars
- isAmbiguousTyVar :: TcTyVar -> Bool
- isCycleBreakerTyVar :: TcTyVar -> Bool
- metaTyVarRef :: TyVar -> IORef MetaDetails
- metaTyVarInfo :: TcTyVar -> MetaInfo
- isFlexi :: MetaDetails -> Bool
- isIndirect :: MetaDetails -> Bool
- isRuntimeUnkSkol :: TyVar -> Bool
- isQLInstTyVar :: TcTyVar -> Bool
- isRuntimeUnkTyVar :: TcTyVar -> Bool
- metaTyVarTcLevel :: TcTyVar -> TcLevel
- setMetaTyVarTcLevel :: TcTyVar -> TcLevel -> TcTyVar
- metaTyVarTcLevel_maybe :: TcTyVar -> Maybe TcLevel
- isTouchableMetaTyVar :: TcLevel -> TcTyVar -> Bool
- isPromotableMetaTyVar :: TcTyVar -> Bool
- findDupTyVarTvs :: [(Name, TcTyVar)] -> [(Name, Name)]
- mkTyVarNamePairs :: [TyVar] -> [(Name, TyVar)]
- mkInfSigmaTy :: HasDebugCallStack => [TyCoVar] -> [PredType] -> Type -> Type
- mkSpecSigmaTy :: HasDebugCallStack => [TyVar] -> [PredType] -> Type -> Type
- mkSigmaTy :: HasDebugCallStack => [ForAllTyBinder] -> [PredType] -> Type -> Type
- mkPhiTy :: HasDebugCallStack => [PredType] -> Type -> Type
- tcMkPhiTy :: HasDebugCallStack => [PredType] -> Type -> Type
- tcMkDFunSigmaTy :: [TyVar] -> ThetaType -> Type -> Type
- tcMkDFunPhiTy :: HasDebugCallStack => [PredType] -> Type -> Type
- getTyVar :: HasDebugCallStack => Type -> TyVar
- getTyVar_maybe :: Type -> Maybe TyVar
- getCastedTyVar_maybe :: Type -> Maybe (TyVar, CoercionN)
- tcSplitForAllTyVarBinder_maybe :: Type -> Maybe (TyVarBinder, Type)
- tcSplitForAllTyVarsReqTVBindersN :: Arity -> Type -> (Arity, [ForAllTyBinder], Type)
- tcSplitForAllTyVars :: Type -> ([TyVar], Type)
- tcSplitForAllInvisTyVars :: Type -> ([TyVar], Type)
- tcSplitSomeForAllTyVars :: (ForAllTyFlag -> Bool) -> Type -> ([TyVar], Type)
- tcSplitForAllReqTVBinders :: Type -> ([TcReqTVBinder], Type)
- tcSplitForAllInvisTVBinders :: Type -> ([TcInvisTVBinder], Type)
- tcSplitPiTys :: Type -> ([PiTyVarBinder], Type)
- tcSplitPiTy_maybe :: Type -> Maybe (PiTyVarBinder, Type)
- tcSplitForAllTyVarBinders :: Type -> ([TyVarBinder], Type)
- tcSplitPhiTy :: Type -> (ThetaType, Type)
- tcSplitPredFunTy_maybe :: Type -> Maybe (PredType, Type)
- tcSplitFunTy_maybe :: Type -> Maybe (Scaled Type, Type)
- tcSplitFunTys :: Type -> ([Scaled Type], Type)
- tcFunArgTy :: Type -> Scaled Type
- tcFunResultTy :: Type -> Type
- tcFunResultTyN :: HasDebugCallStack => Arity -> Type -> Type
- tcSplitFunTysN :: Arity -> TcRhoType -> Either Arity ([Scaled TcSigmaType], TcSigmaType)
- tcSplitTyConApp :: Type -> (TyCon, [Type])
- tcSplitTyConApp_maybe :: HasDebugCallStack => Type -> Maybe (TyCon, [Type])
- tcTyConAppTyCon :: Type -> TyCon
- tcTyConAppTyCon_maybe :: Type -> Maybe TyCon
- tcTyConAppArgs :: Type -> [Type]
- tcSplitAppTy_maybe :: Type -> Maybe (Type, Type)
- tcSplitAppTy :: Type -> (Type, Type)
- tcSplitAppTys :: Type -> (Type, [Type])
- tcSplitAppTyNoView_maybe :: Type -> Maybe (Type, Type)
- tcSplitSigmaTy :: Type -> ([TyVar], ThetaType, Type)
- tcSplitSigmaTyBndrs :: Type -> ([TcInvisTVBinder], ThetaType, Type)
- tcSplitNestedSigmaTys :: Type -> ([TyVar], ThetaType, Type)
- tcSplitIOType_maybe :: Type -> Maybe (TyCon, Type)
- isSigmaTy :: TcType -> Bool
- isRhoTy :: TcType -> Bool
- isRhoExpTy :: ExpType -> Bool
- isOverloadedTy :: Type -> Bool
- isFloatingPrimTy :: Type -> Bool
- isDoubleTy :: Type -> Bool
- isFloatTy :: Type -> Bool
- isIntTy :: Type -> Bool
- isWordTy :: Type -> Bool
- isStringTy :: Type -> Bool
- isIntegerTy :: Type -> Bool
- isNaturalTy :: Type -> Bool
- isBoolTy :: Type -> Bool
- isUnitTy :: Type -> Bool
- isAnyTy :: Type -> Bool
- isZonkAnyTy :: Type -> Bool
- isCharTy :: Type -> Bool
- isTauTy :: Type -> Bool
- isTauTyCon :: TyCon -> Bool
- tcIsTyVarTy :: Type -> Bool
- isPredTy :: Type -> Bool
- isSimplePredTy :: HasDebugCallStack => Type -> Bool
- isTyVarClassPred :: PredType -> Bool
- checkValidClsArgs :: Bool -> Class -> [KindOrType] -> Bool
- hasTyVarHead :: Type -> Bool
- isRigidTy :: TcType -> Bool
- anyTy_maybe :: Type -> Maybe Kind
- eqType :: HasCallStack => Type -> Type -> Bool
- eqTypes :: [Type] -> [Type] -> Bool
- nonDetCmpType :: Type -> Type -> Ordering
- eqTypeX :: HasCallStack => RnEnv2 -> Type -> Type -> Bool
- pickyEqType :: Type -> Type -> Bool
- tcEqType :: HasDebugCallStack => Type -> Type -> Bool
- tcEqKind :: HasDebugCallStack => Kind -> Kind -> Bool
- tcEqTypeNoKindCheck :: Type -> Type -> Bool
- mayLookIdentical :: Type -> Type -> Bool
- tcEqTyConApps :: TyCon -> [Type] -> TyCon -> [Type] -> Bool
- eqForAllVis :: ForAllTyFlag -> ForAllTyFlag -> Bool
- eqVarBndrs :: HasCallStack => RnEnv2 -> [Var] -> [Var] -> Maybe RnEnv2
- deNoteType :: Type -> Type
- getDFunTyKey :: Type -> OccName
- evVarPred :: EvVar -> PredType
- ambigTkvsOfTy :: TcType -> ([Var], [Var])
- mkMinimalBySCs :: (a -> PredType) -> [a] -> [a]
- transSuperClasses :: PredType -> [PredType]
- pickCapturedPreds :: TyVarSet -> TcThetaType -> TcThetaType
- immSuperClasses :: Class -> [Type] -> [PredType]
- boxEqPred :: EqRel -> Type -> Type -> Maybe (Class, [Type])
- isImprovementPred :: PredType -> Bool
- tcTyFamInsts :: Type -> [(TyCon, [Type])]
- tcTyFamInstsAndVis :: Type -> [(Bool, TyCon, [Type])]
- tcTyConAppTyFamInstsAndVis :: TyCon -> [Type] -> [(Bool, TyCon, [Type])]
- isTyFamFree :: Type -> Bool
- exactTyCoVarsOfType :: Type -> TyCoVarSet
- exactTyCoVarsOfTypes :: [Type] -> TyCoVarSet
- anyRewritableTyVar :: EqRel -> (UnderFam -> EqRel -> TcTyVar -> Bool) -> TcType -> Bool
- anyRewritableTyFamApp :: EqRel -> (UnderFam -> EqRel -> TyCon -> [TcType] -> Bool) -> TcType -> Bool
- type UnderFam = Bool
- data PatersonSize
  - = PS_TyFam TyCon
  - | PS_Vanilla {
    - ps_tvs :: [TyVar]
    - ps_size :: Int
    }
- data PatersonCondFailure
  - = PCF_TyVar [TyVar]
  - | PCF_Size
  - | PCF_TyFam TyCon
- data PatersonCondFailureContext
  - = InInstanceDecl
  - | InTyFamEquation
- ltPatersonSize :: PatersonSize -> PatersonSize -> Maybe PatersonCondFailure
- pSizeZero :: PatersonSize
- pSizeOne :: PatersonSize
- pSizeType :: Type -> PatersonSize
- pSizeTypeX :: VarSet -> Type -> PatersonSize
- pSizeTypes :: [Type] -> PatersonSize
- pSizeClassPred :: Class -> [Type] -> PatersonSize
- pSizeClassPredX :: VarSet -> Class -> [Type] -> PatersonSize
- pSizeTyConApp :: TyCon -> [Type] -> PatersonSize
- pSizeHead :: PredType -> PatersonSize
- noMoreTyVars :: [TyVar] -> [TyVar] -> [TyVar]
- allDistinctTyVars :: TyVarSet -> [KindOrType] -> Bool
- type TypeSize = IntWithInf
- sizeType :: Type -> TypeSize
- sizeTypes :: [Type] -> TypeSize
- scopedSort :: [Var] -> [Var]
- isTerminatingClass :: Class -> Bool
- isStuckTypeFamily :: TyCon -> Bool
- type Kind = Type
- liftedTypeKind :: Type
- constraintKind :: Kind
- isLiftedTypeKind :: Kind -> Bool
- isUnliftedTypeKind :: Kind -> Bool
- isTYPEorCONSTRAINT :: Kind -> Bool
- data Type
- type PredType = Type
- type ThetaType = [PredType]
- data PiTyBinder
- data ForAllTyFlag where
  - Invisible !Specificity
  - Required
  - pattern Specified :: ForAllTyFlag
  - pattern Inferred :: ForAllTyFlag
- data FunTyFlag
  - = FTF_T_T
  - | FTF_T_C
  - | FTF_C_T
  - | FTF_C_C
- mkForAllTy :: ForAllTyBinder -> Type -> Type
- mkForAllTys :: [ForAllTyBinder] -> Type -> Type
- mkInvisForAllTys :: [InvisTVBinder] -> Type -> Type
- mkTyCoInvForAllTys :: [TyCoVar] -> Type -> Type
- mkSpecForAllTys :: [TyVar] -> Type -> Type
- mkTyCoInvForAllTy :: TyCoVar -> Type -> Type
- mkInfForAllTy :: TyVar -> Type -> Type
- mkInfForAllTys :: [TyVar] -> Type -> Type
- mkVisFunTy :: HasDebugCallStack => Mult -> Type -> Type -> Type
- mkVisFunTyMany :: HasDebugCallStack => Type -> Type -> Type
- mkVisFunTysMany :: [Type] -> Type -> Type
- mkScaledFunTys :: HasDebugCallStack => [Scaled Type] -> Type -> Type
- mkInvisFunTy :: HasDebugCallStack => Type -> Type -> Type
- mkInvisFunTys :: HasDebugCallStack => [Type] -> Type -> Type
- mkTyConApp :: TyCon -> [Type] -> Type
- mkAppTy :: Type -> Type -> Type
- mkAppTys :: Type -> [Type] -> Type
- mkTyConTy :: TyCon -> Type
- mkTyVarTy :: TyVar -> Type
- mkTyVarTys :: [TyVar] -> [Type]
- mkTyCoVarTy :: TyCoVar -> Type
- mkTyCoVarTys :: [TyCoVar] -> [Type]
- isClassPred :: PredType -> Bool
- isEqPred :: PredType -> Bool
- couldBeIPLike :: Type -> Bool
- isEqClassPred :: PredType -> Bool
- isEqualityClass :: Class -> Bool
- mkClassPred :: Class -> [Type] -> PredType
- tcSplitQuantPredTy :: Type -> ([TyVar], [Type], PredType)
- tcSplitDFunTy :: Type -> ([TyVar], [Type], Class, [Type])
- tcSplitDFunHead :: Type -> (Class, [Type])
- tcSplitMethodTy :: Type -> ([TyVar], PredType, Type)
- isRuntimeRepVar :: TyVar -> Bool
- isFixedRuntimeRepKind :: HasDebugCallStack => Kind -> Bool
- isVisiblePiTyBinder :: PiTyBinder -> Bool
- isInvisiblePiTyBinder :: PiTyBinder -> Bool
- data Subst = Subst InScopeSet IdSubstEnv TvSubstEnv CvSubstEnv
- type TvSubstEnv = TyVarEnv Type
- emptySubst :: Subst
- mkEmptySubst :: InScopeSet -> Subst
- zipTvSubst :: HasDebugCallStack => [TyVar] -> [Type] -> Subst
- mkTvSubstPrs :: [(TyVar, Type)] -> Subst
- notElemSubst :: Var -> Subst -> Bool
- unionSubst :: Subst -> Subst -> Subst
- getTvSubstEnv :: Subst -> TvSubstEnv
- substInScopeSet :: Subst -> InScopeSet
- extendSubstInScope :: Subst -> Var -> Subst
- extendSubstInScopeList :: Subst -> [Var] -> Subst
- extendSubstInScopeSet :: Subst -> VarSet -> Subst
- extendTvSubstAndInScope :: Subst -> TyVar -> Type -> Subst
- lookupTyVar :: Subst -> TyVar -> Maybe Type
- extendTCvSubst :: Subst -> TyCoVar -> Type -> Subst
- substTyVarBndr :: HasDebugCallStack => Subst -> TyVar -> (Subst, TyVar)
- extendTvSubst :: Subst -> TyVar -> Type -> Subst
- isInScope :: Var -> Subst -> Bool
- mkTCvSubst :: InScopeSet -> TvSubstEnv -> CvSubstEnv -> Subst
- mkTvSubst :: InScopeSet -> TvSubstEnv -> Subst
- zipTyEnv :: HasDebugCallStack => [TyVar] -> [Type] -> TvSubstEnv
- zipCoEnv :: HasDebugCallStack => [CoVar] -> [Coercion] -> CvSubstEnv
- substTy :: HasDebugCallStack => Subst -> Type -> Type
- substTys :: HasDebugCallStack => Subst -> [Type] -> [Type]
- substScaledTys :: HasDebugCallStack => Subst -> [Scaled Type] -> [Scaled Type]
- substTyWith :: HasDebugCallStack => [TyVar] -> [Type] -> Type -> Type
- substTyWithCoVars :: [CoVar] -> [Coercion] -> Type -> Type
- substTyAddInScope :: HasDebugCallStack => Subst -> Type -> Type
- substTyUnchecked :: Subst -> Type -> Type
- substTysUnchecked :: Subst -> [Type] -> [Type]
- substScaledTyUnchecked :: HasDebugCallStack => Subst -> Scaled Type -> Scaled Type
- substThetaUnchecked :: Subst -> ThetaType -> ThetaType
- substTyWithUnchecked :: [TyVar] -> [Type] -> Type -> Type
- substCoUnchecked :: Subst -> Coercion -> Coercion
- substCoWithUnchecked :: [TyVar] -> [Type] -> Coercion -> Coercion
- substTheta :: HasDebugCallStack => Subst -> ThetaType -> ThetaType
- isUnliftedType :: HasDebugCallStack => Type -> Bool
- isUnboxedTupleType :: Type -> Bool
- isPrimitiveType :: Type -> Bool
- coreView :: Type -> Maybe Type
- tyCoVarsOfType :: Type -> TyCoVarSet
- tyCoVarsOfTypes :: [Type] -> TyCoVarSet
- closeOverKinds :: TyCoVarSet -> TyCoVarSet
- tyCoFVsOfType :: Type -> FV
- tyCoFVsOfTypes :: [Type] -> FV
- tyCoVarsOfTypeDSet :: Type -> DTyCoVarSet
- tyCoVarsOfTypesDSet :: [Type] -> DTyCoVarSet
- closeOverKindsDSet :: DTyVarSet -> DTyVarSet
- tyCoVarsOfTypeList :: Type -> [TyCoVar]
- tyCoVarsOfTypesList :: [Type] -> [TyCoVar]
- noFreeVarsOfType :: Type -> Bool
- pprKind :: Kind -> SDoc
- pprParendKind :: Kind -> SDoc
- pprSigmaType :: Type -> SDoc
- pprType :: Type -> SDoc
- pprParendType :: Type -> SDoc
- pprTypeApp :: TyCon -> [Type] -> SDoc
- pprTheta :: ThetaType -> SDoc
- pprParendTheta :: ThetaType -> SDoc
- pprThetaArrowTy :: ThetaType -> SDoc
- pprClassPred :: Class -> [Type] -> SDoc
- pprTCvBndr :: ForAllTyBinder -> SDoc
- pprTCvBndrs :: [ForAllTyBinder] -> SDoc
- tyConVisibilities :: TyCon -> [Bool]
- isNextTyConArgVisible :: TyCon -> [Type] -> Bool
- isNextArgVisible :: TcType -> Bool

# Documentation

type TcType = Type #

type TcSigmaType = TcType #

type TcTypeFRR = TcType #

A type which has a syntactically fixed RuntimeRep as per Note [Fixed RuntimeRep] in GHC.Tc.Utils.Concrete.

type TcSigmaTypeFRR = TcSigmaType #

A `TcSigmaTypeFRR` is a `TcSigmaType` which has a syntactically fixed `RuntimeRep` in the sense of Note [Fixed RuntimeRep] in GHC.Tc.Utils.Concrete.

In particular, this means that:

- `typePrimRep` does not panic,
- `typeLevity_maybe` does not return `Nothing`.

This property is important in functions such as `matchExpectedFunTys`, where we want to provide argument types which have a known runtime representation. See Note [Return arguments with a fixed RuntimeRep.

type TcRhoType = TcType #

type TcRhoTypeFRR = TcRhoType #

type TcTauType = TcType #

type TcPredType = PredType #

type TcThetaType = ThetaType #

type TcTyVar = Var #

Type variable that might be a metavariable

type TcTyVarSet = TyVarSet #

type TcDTyVarSet = DTyVarSet #

type TcTyCoVarSet = TyCoVarSet #

type TcDTyCoVarSet = DTyCoVarSet #

type TcKind = Kind #

type TcCoVar = CoVar #

type TcTyCoVar = Var #

type TcTyVarBinder = TyVarBinder #

type TcInvisTVBinder = InvisTVBinder #

type TcReqTVBinder = ReqTVBinder #

type TcTyCon = TyCon #

type MonoTcTyCon = TcTyCon #

type PolyTcTyCon = TcTyCon #

type TcTyConBinder = TyConBinder #

type KnotTied (ty :: k) = ty #

A type labeled `KnotTied` might have knot-tied tycons in it. See Note [Type checking recursive type and class declarations] in GHC.Tc.TyCl

data ExpType #

An expected type to check against during type-checking. See Note [ExpType] in GHC.Tc.Utils.TcMType, where you'll also find manipulators.

Constructors

Check TcType |
Infer !InferResult |

#### Instances

Instances details

Outputable ExpType # |
Instance details Defined in GHC.Tc.Utils.TcType Methods ppr :: ExpType -> SDoc #

type ExpKind = ExpType #

Like `ExpType`, but on kind level

data InferResult #

Constructors

IR |
Fields ir_uniq :: Unique This `Unique` is for debugging only ir_lvl :: TcLevel See Note [TcLevel of ExpType] in GHC.Tc.Utils.TcMType ir_frr :: InferFRRFlag See Note [FixedRuntimeRep context in ExpType] in GHC.Tc.Utils.TcMType ir_inst :: InferInstFlag True = when DeepSubsumption is on, deeply instantiate before filling, See Note [Instantiation of InferResult] in GHC.Tc.Utils.Unify ir_ref :: IORef (Maybe TcType) The type that fills in this hole should be a `Type`, that is, its kind should be `TYPE rr` for some `rr :: RuntimeRep`. Additionally, if the `ir_frr` field is `Just frr_orig` then `rr` must be concrete, in the sense of Note [Concrete types] in GHC.Tc.Utils.Concrete.

#### Instances

Instances details

Outputable InferResult # |
Instance details Defined in GHC.Tc.Utils.TcType Methods ppr :: InferResult -> SDoc #

data InferInstFlag #

Constructors

IIF_Sigma |
IIF_ShallowRho |
IIF_DeepRho |

data InferFRRFlag #

Constructors

IFRR_Check FixedRuntimeRepContext |
IFRR_Any |

type ExpTypeFRR = ExpType #

An `ExpType` which has a fixed RuntimeRep.

For a `Check` `ExpType`, the stored `TcType` must have a fixed RuntimeRep. For an `Infer` `ExpType`, the `ir_frr` field must be of the form `IFRR_Check frr_orig`.

type ExpSigmaType = ExpType #

type ExpSigmaTypeFRR = ExpTypeFRR #

Like `TcSigmaTypeFRR`, but for an expected type.

See `ExpTypeFRR`.

type ExpRhoType = ExpType #

type ExpRhoTypeFRR = ExpTypeFRR #

mkCheckExpType :: TcType -> ExpType #

Make an `ExpType` suitable for checking.

checkingExpType_maybe :: ExpType -> Maybe TcType #

Returns the expected type when in checking mode.

checkingExpType :: ExpType -> TcType #

Returns the expected type when in checking mode. Panics if in inference mode.

data ExpPatType #

Constructors

ExpFunPatTy (Scaled ExpSigmaTypeFRR) |
ExpForAllPatTy ForAllTyBinder |

#### Instances

Instances details

Outputable ExpPatType # |
Instance details Defined in GHC.Tc.Utils.TcType Methods ppr :: ExpPatType -> SDoc #

mkCheckExpFunPatTy :: Scaled TcType -> ExpPatType #

mkInvisExpPatType :: InvisTyBinder -> ExpPatType #

isVisibleExpPatType :: ExpPatType -> Bool #

isExpFunPatType :: ExpPatType -> Bool #

data SyntaxOpType #

What to expect for an argument to a rebindable-syntax operator. Quite like `Type`, but allows for holes to be filled in by tcSyntaxOp. The callback called from tcSyntaxOp gets a list of types; the meaning of these types is determined by a left-to-right depth-first traversal of the `SyntaxOpType` tree. So if you pass in

    SynAny `SynFun` (SynList `SynFun` SynType Int) `SynFun` SynAny

you'll get three types back: one for the first `SynAny`, the element type of the list, and one for the last `SynAny`. You don't get anything for the `SynType`, because you've said positively that it should be an Int, and so it shall be.

You'll also get three multiplicities back: one for each function arrow. See also Note [Linear types] in Multiplicity.

This is defined here to avoid defining it in GHC.Tc.Gen.Expr boot file.

Constructors

SynAny | Any type
SynRho | A rho type, skolemised or instantiated as appropriate
SynList | A list type. You get back the element type of the list
SynFun SyntaxOpType SyntaxOpType infixr 0 | A function.
SynType ExpType | A known type.

synKnownType :: TcType -> SyntaxOpType #

Like `SynType` but accepts a regular TcType

mkSynFunTys :: [SyntaxOpType] -> ExpType -> SyntaxOpType #

Like `mkFunTys` but for `SyntaxOpType`

data TcLevel #

Constructors

TcLevel !Int |
QLInstVar |

#### Instances

Instances details

Outputable TcLevel # |
Instance details Defined in GHC.Tc.Utils.TcType Methods ppr :: TcLevel -> SDoc #

topTcLevel :: TcLevel #

pushTcLevel :: TcLevel -> TcLevel #

isTopTcLevel :: TcLevel -> Bool #

strictlyDeeperThan :: TcLevel -> TcLevel -> Bool #

deeperThanOrSame :: TcLevel -> TcLevel -> Bool #

sameDepthAs :: TcLevel -> TcLevel -> Bool #

tcTypeLevel :: TcType -> TcLevel #

tcTyVarLevel :: TcTyVar -> TcLevel #

maxTcLevel :: TcLevel -> TcLevel -> TcLevel #

minTcLevel :: TcLevel -> TcLevel -> TcLevel #

data TcTyVarDetails #

Constructors

SkolemTv SkolemInfo TcLevel Bool |
RuntimeUnk |
MetaTv |
Fields mtv_info :: MetaInfo mtv_ref :: IORef MetaDetails mtv_tclvl :: TcLevel

#### Instances

Instances details

Outputable TcTyVarDetails # |
Instance details Defined in GHC.Tc.Utils.TcType Methods ppr :: TcTyVarDetails -> SDoc #

pprTcTyVarDetails :: TcTyVarDetails -> SDoc #

vanillaSkolemTvUnk :: HasDebugCallStack => TcTyVarDetails #

data MetaDetails #

Constructors

Flexi |
Indirect TcType |

#### Instances

Instances details

Outputable MetaDetails # |
Instance details Defined in GHC.Tc.Utils.TcType Methods ppr :: MetaDetails -> SDoc #

data MetaInfo #

What restrictions are on this metavariable around unification? These are checked in GHC.Tc.Utils.Unify.checkTopShape

Constructors

TauTv | This MetaTv is an ordinary unification variable A TauTv is always filled in with a tau-type, which never contains any ForAlls.
TyVarTv | A variant of TauTv, except that it should not be unified with a type, only with a type variable See Note [TyVarTv] in GHC.Tc.Utils.TcMType
RuntimeUnkTv | A unification variable used in the GHCi debugger. It is allowed to unify with a polytype, unlike TauTv
CycleBreakerTv | Used to fix occurs-check problems in Givens See Note [Type equality cycles] in GHC.Tc.Solver.Equality
ConcreteTv ConcreteTvOrigin | A unification variable that can only be unified with a concrete type, in the sense of Note [Concrete types] in GHC.Tc.Utils.Concrete. See Note [ConcreteTv] in GHC.Tc.Utils.Concrete. See also Note [The Concrete mechanism] in GHC.Tc.Utils.Concrete for an overview of how this works in context.

#### Instances

Instances details

Outputable MetaInfo # |
Instance details Defined in GHC.Tc.Utils.TcType Methods ppr :: MetaInfo -> SDoc #

skolemSkolInfo :: TcTyVar -> SkolemInfo #

isImmutableTyVar :: TyVar -> Bool #

isSkolemTyVar :: TcTyVar -> Bool #

isMetaTyVar :: TcTyVar -> Bool #

isMetaTyVarTy :: TcType -> Bool #

isTyVarTy :: Type -> Bool #

tcIsTcTyVar :: TcTyVar -> Bool #

isTyVarTyVar :: Var -> Bool #

isOverlappableTyVar :: TcTyVar -> Bool #

isTyConableTyVar :: TcTyVar -> Bool #

data ConcreteTvOrigin #

What caused us to create a `ConcreteTv` metavariable? See Note [ConcreteTv] in GHC.Tc.Utils.Concrete.

Constructors

ConcreteFRR FixedRuntimeRepOrigin | A `ConcreteTv` used to enforce the representation-polymorphism invariants. See `FixedRuntimeRepOrigin` for more information.

isConcreteTyVar_maybe :: TcTyVar -> Maybe ConcreteTvOrigin #

Is this type variable a concrete type variable, i.e. it is a metavariable with `ConcreteTv` `MetaInfo`?

Returns the `ConcreteTvOrigin` stored in the type variable if so, or `Nothing` otherwise.

isConcreteTyVar :: TcTyVar -> Bool #

Is this type variable a concrete type variable, i.e. it is a metavariable with `ConcreteTv` `MetaInfo`?

isConcreteTyVarTy :: TcType -> Bool #

Is this type concrete type variable, i.e. a metavariable with `ConcreteTv` `MetaInfo`?

isConcreteTyVarTy_maybe :: TcType -> Maybe (TcTyVar, ConcreteTvOrigin) #

Is this type a concrete type variable? If so, return the associated `TcTyVar` and `ConcreteTvOrigin`.

concreteInfo_maybe :: MetaInfo -> Maybe ConcreteTvOrigin #

type ConcreteTyVars = NameEnv ConcreteTvOrigin #

A mapping from skolem type variable `Name` to concreteness information,

See Note [Representation-polymorphism checking built-ins] in GHC.Tc.Utils.Concrete.

noConcreteTyVars :: ConcreteTyVars #

The `Id` has no outer forall'd type variables which must be instantiated to concrete types.

isAmbiguousTyVar :: TcTyVar -> Bool #

isCycleBreakerTyVar :: TcTyVar -> Bool #

metaTyVarRef :: TyVar -> IORef MetaDetails #

metaTyVarInfo :: TcTyVar -> MetaInfo #

isFlexi :: MetaDetails -> Bool #

isIndirect :: MetaDetails -> Bool #

isRuntimeUnkSkol :: TyVar -> Bool #

isQLInstTyVar :: TcTyVar -> Bool #

isRuntimeUnkTyVar :: TcTyVar -> Bool #

metaTyVarTcLevel :: TcTyVar -> TcLevel #

setMetaTyVarTcLevel :: TcTyVar -> TcLevel -> TcTyVar #

metaTyVarTcLevel_maybe :: TcTyVar -> Maybe TcLevel #

isTouchableMetaTyVar :: TcLevel -> TcTyVar -> Bool #

isPromotableMetaTyVar :: TcTyVar -> Bool #

findDupTyVarTvs :: [(Name, TcTyVar)] -> [(Name, Name)] #

mkTyVarNamePairs :: [TyVar] -> [(Name, TyVar)] #

mkInfSigmaTy :: HasDebugCallStack => [TyCoVar] -> [PredType] -> Type -> Type #

Make a sigma ty where all type variables are `Inferred`. That is, they cannot be used with visible type application.

mkSpecSigmaTy :: HasDebugCallStack => [TyVar] -> [PredType] -> Type -> Type #

Make a sigma ty where all type variables are "specified". That is, they can be used with visible type application

mkSigmaTy :: HasDebugCallStack => [ForAllTyBinder] -> [PredType] -> Type -> Type #

mkPhiTy :: HasDebugCallStack => [PredType] -> Type -> Type #

tcMkPhiTy :: HasDebugCallStack => [PredType] -> Type -> Type #

tcMkDFunSigmaTy :: [TyVar] -> ThetaType -> Type -> Type #

tcMkDFunPhiTy :: HasDebugCallStack => [PredType] -> Type -> Type #

getTyVar :: HasDebugCallStack => Type -> TyVar #

Attempts to obtain the type variable underlying a `Type`, and panics with the given message if this is not a type variable type. See also `getTyVar_maybe`

getTyVar_maybe :: Type -> Maybe TyVar #

Attempts to obtain the type variable underlying a `Type`

getCastedTyVar_maybe :: Type -> Maybe (TyVar, CoercionN) #

If the type is a tyvar, possibly under a cast, returns it, along with the coercion. Thus, the co is :: kind tv ~N kind ty

tcSplitForAllTyVarBinder_maybe :: Type -> Maybe (TyVarBinder, Type) #

tcSplitForAllTyVarsReqTVBindersN :: Arity -> Type -> (Arity, [ForAllTyBinder], Type) #

tcSplitForAllTyVars :: Type -> ([TyVar], Type) #

Like `tcSplitPiTys`, but splits off only named binders, returning just the tyvars.

tcSplitForAllInvisTyVars :: Type -> ([TyVar], Type) #

Like `tcSplitForAllTyVars`, but only splits `ForAllTy`s with `Invisible` type variable binders.

tcSplitSomeForAllTyVars :: (ForAllTyFlag -> Bool) -> Type -> ([TyVar], Type) #

Like `tcSplitForAllTyVars`, but only splits a `ForAllTy` if `argf_pred argf` is `True`, where `argf` is the visibility of the `ForAllTy`'s binder and `argf_pred` is a predicate over visibilities provided as an argument to this function.

tcSplitForAllReqTVBinders :: Type -> ([TcReqTVBinder], Type) #

Like `tcSplitForAllTyVars`, but only splits `ForAllTy`s with `Required` type variable binders. All split tyvars are annotated with `()`.

tcSplitForAllInvisTVBinders :: Type -> ([TcInvisTVBinder], Type) #

Like `tcSplitForAllTyVars`, but only splits `ForAllTy`s with `Invisible` type variable binders. All split tyvars are annotated with their `Specificity`.

tcSplitPiTys :: Type -> ([PiTyVarBinder], Type) #

Splits a forall type into a list of `PiTyVarBinder`s and the inner type. Always succeeds, even if it returns an empty list.

tcSplitPiTy_maybe :: Type -> Maybe (PiTyVarBinder, Type) #

Splits a type into a PiTyVarBinder and a body, if possible.

tcSplitForAllTyVarBinders :: Type -> ([TyVarBinder], Type) #

Like `tcSplitForAllTyVars`, but splits off only named binders.

tcSplitPhiTy :: Type -> (ThetaType, Type) #

tcSplitPredFunTy_maybe :: Type -> Maybe (PredType, Type) #

tcSplitFunTy_maybe :: Type -> Maybe (Scaled Type, Type) #

tcSplitFunTys :: Type -> ([Scaled Type], Type) #

tcFunArgTy :: Type -> Scaled Type #

tcFunResultTy :: Type -> Type #

tcFunResultTyN :: HasDebugCallStack => Arity -> Type -> Type #

Strips off n *visible* arguments and returns the resulting type

tcSplitFunTysN :: Arity -> TcRhoType -> Either Arity ([Scaled TcSigmaType], TcSigmaType) #

Split off exactly the specified number argument types Returns (Left m) if there are `m` missing arrows in the type (Right (tys,res)) if the type looks like t1 -> ... -> tn -> res

tcSplitTyConApp :: Type -> (TyCon, [Type]) #

tcSplitTyConApp_maybe :: HasDebugCallStack => Type -> Maybe (TyCon, [Type]) #

tcSplitTyConApp_maybe splits a type constructor application into its type constructor and applied types.

Differs from splitTyConApp_maybe in that it does *not* split types headed with (=>), as that's not a TyCon in the type-checker.

Note that this may fail (in funTyConAppTy_maybe) in the case of a `FunTy` with an argument of unknown kind `FunTy` (e.g. `FunTy (a :: k) Int`, since the kind of `a` isn't of the form `TYPE rep`. This isn't usually a problem but may be temporarily the case during canonicalization: see Note [Decomposing FunTy] in GHC.Tc.Solver.Equality and Note [The Purely Kinded Type Invariant (PKTI)] in GHC.Tc.Gen.HsType, Wrinkle around FunTy

Consequently, you may need to zonk your type before using this function.

tcTyConAppTyCon :: Type -> TyCon #

tcTyConAppTyCon_maybe :: Type -> Maybe TyCon #

Like `tcRepSplitTyConApp_maybe`, but only returns the `TyCon`.

tcTyConAppArgs :: Type -> [Type] #

tcSplitAppTy_maybe :: Type -> Maybe (Type, Type) #

tcSplitAppTy :: Type -> (Type, Type) #

tcSplitAppTys :: Type -> (Type, [Type]) #

tcSplitAppTyNoView_maybe :: Type -> Maybe (Type, Type) #

Just like splitAppTyNoView_maybe, but does not split (c => t) See Note [Decomposing fat arrow c=>t]

tcSplitSigmaTy :: Type -> ([TyVar], ThetaType, Type) #

Split a sigma type into its parts. This only splits invisible type variable binders, as these are the only forms of binder that the typechecker will implicitly instantiate.

tcSplitSigmaTyBndrs :: Type -> ([TcInvisTVBinder], ThetaType, Type) #

tcSplitNestedSigmaTys :: Type -> ([TyVar], ThetaType, Type) #

Split a sigma type into its parts, going underneath as many arrows and foralls as possible. See Note [tcSplitNestedSigmaTys]

tcSplitIOType_maybe :: Type -> Maybe (TyCon, Type) #

isSigmaTy :: TcType -> Bool #

isRhoTy :: TcType -> Bool #

isRhoExpTy :: ExpType -> Bool #

Like `isRhoTy`, but also says `True` for `Infer` types

isOverloadedTy :: Type -> Bool #

isFloatingPrimTy :: Type -> Bool #

Is the type inhabited by machine floating-point numbers?

Used to check that we don't use floating-point literal patterns in Core.

See #9238 and Note [Rules for floating-point comparisons] in GHC.Core.Opt.ConstantFold.

isDoubleTy :: Type -> Bool #

isFloatTy :: Type -> Bool #

isIntTy :: Type -> Bool #

isWordTy :: Type -> Bool #

isStringTy :: Type -> Bool #

Is a type `String`?

isIntegerTy :: Type -> Bool #

isNaturalTy :: Type -> Bool #

isBoolTy :: Type -> Bool #

isUnitTy :: Type -> Bool #

isAnyTy :: Type -> Bool #

isZonkAnyTy :: Type -> Bool #

isCharTy :: Type -> Bool #

isTauTy :: Type -> Bool #

isTauTyCon :: TyCon -> Bool #

tcIsTyVarTy :: Type -> Bool #

isPredTy :: Type -> Bool #

isSimplePredTy :: HasDebugCallStack => Type -> Bool #

isTyVarClassPred :: PredType -> Bool #

checkValidClsArgs :: Bool -> Class -> [KindOrType] -> Bool #

hasTyVarHead :: Type -> Bool #

isRigidTy :: TcType -> Bool #

anyTy_maybe :: Type -> Maybe Kind #

Check whether the type is of the form `Any :: k`, returning the kind `k`.

eqType :: HasCallStack => Type -> Type -> Bool #

Type equality comparing both visible and invisible arguments, expanding synonyms and respecting multiplicities.

eqTypes :: [Type] -> [Type] -> Bool #

Type equality on lists of types, looking through type synonyms

nonDetCmpType :: Type -> Type -> Ordering #

eqTypeX :: HasCallStack => RnEnv2 -> Type -> Type -> Bool #

Compare types with respect to a (presumably) non-empty `RnEnv2`.

pickyEqType :: Type -> Type -> Bool #

Like `pickyEqTypeVis`, but returns a Bool for convenience

tcEqType :: HasDebugCallStack => Type -> Type -> Bool #

tcEqKind :: HasDebugCallStack => Kind -> Kind -> Bool #

tcEqTypeNoKindCheck :: Type -> Type -> Bool #

Just like `tcEqType`, but will return True for types of different kinds as long as their non-coercion structure is identical.

mayLookIdentical :: Type -> Type -> Bool #

Returns True if the visible part of the types might look equal, even if they are really unequal (in the invisible bits)

This function is very similar to tc_eq_type but it is much more heuristic. Notably, it is always safe to return True, even with types that might (in truth) be unequal -- this affects error messages only (Originally this test was done by eqType with an extra flag, but the result was hard to understand.)

tcEqTyConApps :: TyCon -> [Type] -> TyCon -> [Type] -> Bool #

Check whether two TyConApps are the same; if the number of arguments are different, just checks the common prefix of arguments.

eqForAllVis :: ForAllTyFlag -> ForAllTyFlag -> Bool #

Do these denote the same level of visibility? `Required` arguments are visible, others are not. So this function equates `Specified` and `Inferred`. Used for printing.

eqVarBndrs :: HasCallStack => RnEnv2 -> [Var] -> [Var] -> Maybe RnEnv2 #

deNoteType :: Type -> Type #

getDFunTyKey :: Type -> OccName #

evVarPred :: EvVar -> PredType #

ambigTkvsOfTy :: TcType -> ([Var], [Var]) #

Returns the (kind, type) variables in a type that are as-yet-unknown: metavariables and RuntimeUnks

mkMinimalBySCs :: (a -> PredType) -> [a] -> [a] #

transSuperClasses :: PredType -> [PredType] #

pickCapturedPreds :: TyVarSet -> TcThetaType -> TcThetaType #

immSuperClasses :: Class -> [Type] -> [PredType] #

boxEqPred :: EqRel -> Type -> Type -> Maybe (Class, [Type]) #

isImprovementPred :: PredType -> Bool #

# Finding type instances

tcTyFamInsts :: Type -> [(TyCon, [Type])] #

Finds outermost type-family applications occurring in a type, after expanding synonyms. In the list (F, tys) that is returned we guarantee that tys matches F's arity. For example, given type family F a :: * -> * (arity 1) calling tcTyFamInsts on (Maybe (F Int Bool) will return (F, [Int]), not (F, [Int,Bool])

This is important for its use in deciding termination of type instances (see #11581). E.g. type instance G [Int] = ...(F Int <big type>)... we don't need to take <big type> into account when asking if the calls on the RHS are smaller than the LHS

tcTyFamInstsAndVis :: Type -> [(Bool, TyCon, [Type])] #

Like `tcTyFamInsts`, except that the output records whether the type family and its arguments occur as an invisible argument in some type application. This information is useful because it helps GHC know when to turn on `-fprint-explicit-kinds` during error reporting so that users can actually see the type family being mentioned.

As an example, consider:

    class C a
    data T (a :: k)
    type family F a :: k
    instance C (T @(F Int) (F Bool))

There are two occurrences of the type family `F` in that `C` instance, so ``tcTyFamInstsAndVis` (C (T @(F Int) (F Bool)))` will return:

    [ (True,  F, [Int])
    , (False, F, [Bool]) ]

`F Int` is paired with `True` since it appears as an invisible argument to `C`, whereas `F Bool` is paired with `False` since it appears an a visible argument to `C`.

See also Note [Showing invisible bits of types in error messages] in GHC.Tc.Errors.Ppr.

tcTyConAppTyFamInstsAndVis :: TyCon -> [Type] -> [(Bool, TyCon, [Type])] #

In an application of a `TyCon` to some arguments, find the outermost occurrences of type family applications within the arguments. This function will not consider the `TyCon` itself when checking for type family applications.

See `tcTyFamInstsAndVis` for more details on how this works (as this function is called inside of `tcTyFamInstsAndVis`).

isTyFamFree :: Type -> Bool #

Check that a type does not contain any type family applications.

# Finding "exact" (non-dead) type variables

exactTyCoVarsOfType :: Type -> TyCoVarSet #

exactTyCoVarsOfTypes :: [Type] -> TyCoVarSet #

anyRewritableTyVar :: EqRel -> (UnderFam -> EqRel -> TcTyVar -> Bool) -> TcType -> Bool #

anyRewritableTyFamApp :: EqRel -> (UnderFam -> EqRel -> TyCon -> [TcType] -> Bool) -> TcType -> Bool #

type UnderFam = Bool #

data PatersonSize #

The Paterson size of a given type, in the sense of Note [Paterson conditions] in GHC.Tc.Validity

- after expanding synonyms,
- ignoring coercions (as they are not user written).

Constructors

PS_TyFam TyCon | The type mentions a type family, so the size could be anything.
PS_Vanilla | The type does not mention a type family.
Fields ps_tvs :: [TyVar] free tyvars, including repetitions; ps_size :: Int number of type constructors and variables

#### Instances

Instances details

Outputable PatersonSize # |
Instance details Defined in GHC.Tc.Utils.TcType Methods ppr :: PatersonSize -> SDoc #

data PatersonCondFailure #

Why did the Paterson conditions fail; that is, why was the context P not Paterson-smaller than the head H?

See Note [Paterson conditions] in GHC.Tc.Validity.

Constructors

PCF_TyVar | Some type variables occur more often in P than in H. See (PC1) in Note [Paterson conditions] in GHC.Tc.Validity.
Fields [TyVar] the type variables which appear more often in the context | P is not smaller in size than H. See (PC2) in Note [Paterson conditions] in GHC.Tc.Validity.
PCF_Size |
PCF_TyFam | P contains a type family. See (PC3) in Note [Paterson conditions] in GHC.Tc.Validity.
Fields TyCon the type constructor of the type family

data PatersonCondFailureContext #

Indicates whether a Paterson condition failure occurred in an instance declaration or a type family equation. Useful for differentiating context in error messages.

Constructors

InInstanceDecl |
InTyFamEquation |

ltPatersonSize :: PatersonSize -> PatersonSize -> Maybe PatersonCondFailure #

`ltPatersonSize ps1 ps2` returns:

- `Nothing` iff `ps1` is definitely strictly smaller than `ps2`,
- `Just ps_fail` otherwise; `ps_fail` says what went wrong.

pSizeZero :: PatersonSize #

pSizeOne :: PatersonSize #

pSizeType :: Type -> PatersonSize #

pSizeTypeX :: VarSet -> Type -> PatersonSize #

pSizeTypes :: [Type] -> PatersonSize #

pSizeClassPred :: Class -> [Type] -> PatersonSize #

pSizeClassPredX :: VarSet -> Class -> [Type] -> PatersonSize #

pSizeTyConApp :: TyCon -> [Type] -> PatersonSize #

pSizeHead :: PredType -> PatersonSize #

noMoreTyVars :: [TyVar] -> [TyVar] -> [TyVar] #

allDistinctTyVars :: TyVarSet -> [KindOrType] -> Bool #

type TypeSize = IntWithInf #

sizeType :: Type -> TypeSize #

sizeTypes :: [Type] -> TypeSize #

scopedSort :: [Var] -> [Var] #

Do a topological sort on a list of tyvars, so that binders occur before occurrences E.g. given `[ a::k, k::Type, b::k ]` it'll return a well-scoped list `[ k::Type, a::k, b::k ]`.

This is a deterministic sorting operation (that is, doesn't depend on Uniques).

It is also meant to be stable: that is, variables should not be reordered unnecessarily. This is specified in Note [ScopedSort] See also Note [Ordering of implicit variables] in GHC.Rename.HsType

isTerminatingClass :: Class -> Bool #

When this says True, ignore this class constraint during a termination check See (PS1) in Note [The PatersonSize of a type]

isStuckTypeFamily :: TyCon -> Bool #

type Kind = Type #

The key type representing kinds in the compiler.

liftedTypeKind :: Type #

constraintKind :: Kind #

isLiftedTypeKind :: Kind -> Bool #

Returns True if the argument is (lifted) Type or Constraint See Note [TYPE and CONSTRAINT] in GHC.Builtin.Types.Prim

isUnliftedTypeKind :: Kind -> Bool #

Returns True if the kind classifies unlifted types (like 'Int#') and False otherwise. Note that this returns False for representation-polymorphic kinds, which may be specialized to a kind that classifies unlifted types.

isTYPEorCONSTRAINT :: Kind -> Bool #

Does this classify a type allowed to have values? Responds True to things like *, TYPE Lifted, TYPE IntRep, TYPE v, Constraint.

True of a kind `TYPE _` or `CONSTRAINT _`

data Type #

#### Instances

Instances details

Data Type # |
Instance details Defined in GHC.Core.TyCo.Rep Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Type -> c Type # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Type # toConstr :: Type -> Constr # dataTypeOf :: Type -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Type) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Type) # gmapT :: (forall b. Data b => b -> b) -> Type -> Type # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Type -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Type -> r # gmapQ :: (forall d. Data d => d -> u) -> Type -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Type -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Type -> m Type # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Type -> m Type # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Type -> m Type #
Outputable Type # |
Instance details Defined in GHC.Core.TyCo.Rep Methods ppr :: Type -> SDoc #
Eq (DeBruijn Type) # |
Instance details Defined in GHC.Core.Map.Type Methods (==) :: DeBruijn Type -> DeBruijn Type -> Bool # (/=) :: DeBruijn Type -> DeBruijn Type -> Bool #

type PredType = Type #

A type of the form `p` of constraint kind represents a value whose type is the Haskell predicate `p`, where a predicate is what occurs before the `=>` in a Haskell type.

We use `PredType` as documentation to mark those types that we guarantee to have this kind.

It can be expanded into its representation, but:

- The type checker must treat it as opaque
- The rest of the compiler treats it as transparent

Consider these examples:

    f :: (Eq a) => a -> Int
    g :: (?x :: Int -> Int) => a -> Int
    h :: (r\l) => {r} => {l::Int | r}

Here the `Eq a` and `?x :: Int -> Int` and `rl` are all called "predicates"

type ThetaType = [PredType] #

A collection of `PredType`s

data PiTyBinder #

A `PiTyBinder` represents an argument to a function. PiTyBinders can be dependent (`Named`) or nondependent (`Anon`). They may also be visible or not. See Note [PiTyBinders]

#### Instances

Instances details

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

data ForAllTyFlag #

ForAllTyFlag

Is something required to appear in source Haskell (`Required`), permitted by request (`Specified`) (visible type application), or prohibited entirely from appearing in source Haskell (`Inferred`)? See Note [VarBndrs, ForAllTyBinders, TyConBinders, and visibility] in GHC.Core.TyCo.Rep

Constructors

Invisible !Specificity |
Required |

Bundled Patterns

pattern Specified :: ForAllTyFlag |
pattern Inferred :: ForAllTyFlag |

#### Instances

Instances details

NFData ForAllTyFlag # |
Instance details Defined in GHC.Hs.Specificity Methods rnf :: ForAllTyFlag -> () #
Data ForAllTyFlag # |
Instance details Defined in Language.Haskell.Syntax.Specificity Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> ForAllTyFlag -> c ForAllTyFlag # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c ForAllTyFlag # toConstr :: ForAllTyFlag -> Constr # dataTypeOf :: ForAllTyFlag -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c ForAllTyFlag) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c ForAllTyFlag) # gmapT :: (forall b. Data b => b -> b) -> ForAllTyFlag -> ForAllTyFlag # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> ForAllTyFlag -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> ForAllTyFlag -> r # gmapQ :: (forall d. Data d => d -> u) -> ForAllTyFlag -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> ForAllTyFlag -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> ForAllTyFlag -> m ForAllTyFlag # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> ForAllTyFlag -> m ForAllTyFlag # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> ForAllTyFlag -> m ForAllTyFlag #
Binary ForAllTyFlag # |
Instance details Defined in GHC.Hs.Specificity Methods put_ :: WriteBinHandle -> ForAllTyFlag -> IO () # put :: WriteBinHandle -> ForAllTyFlag -> IO (Bin ForAllTyFlag) # get :: ReadBinHandle -> IO ForAllTyFlag #
Outputable ForAllTyFlag # |
Instance details Defined in GHC.Hs.Specificity Methods ppr :: ForAllTyFlag -> SDoc #
Eq ForAllTyFlag # |
Instance details Defined in Language.Haskell.Syntax.Specificity Methods (==) :: ForAllTyFlag -> ForAllTyFlag -> Bool # (/=) :: ForAllTyFlag -> ForAllTyFlag -> Bool #
Ord ForAllTyFlag # |
Instance details Defined in Language.Haskell.Syntax.Specificity Methods compare :: ForAllTyFlag -> ForAllTyFlag -> Ordering # (<) :: ForAllTyFlag -> ForAllTyFlag -> Bool # (<=) :: ForAllTyFlag -> ForAllTyFlag -> Bool # (>) :: ForAllTyFlag -> ForAllTyFlag -> Bool # (>=) :: ForAllTyFlag -> ForAllTyFlag -> Bool # max :: ForAllTyFlag -> ForAllTyFlag -> ForAllTyFlag # min :: ForAllTyFlag -> ForAllTyFlag -> ForAllTyFlag #
OutputableBndrFlag ForAllTyFlag p # |
Instance details Defined in GHC.Hs.Type Methods pprTyVarBndr :: HsTyVarBndr ForAllTyFlag (GhcPass p) -> SDoc
Outputable tv => Outputable (VarBndr tv ForAllTyFlag) # |
Instance details Defined in GHC.Types.Var Methods ppr :: VarBndr tv ForAllTyFlag -> SDoc #

data FunTyFlag #

The non-dependent version of `ForAllTyFlag`. See Note [FunTyFlag] Appears here partly so that it's together with its friends ForAllTyFlag and ForallVisFlag, but also because it is used in IfaceType, rather early in the compilation chain

Constructors

FTF_T_T |
FTF_T_C |
FTF_C_T |
FTF_C_C |

#### Instances

Instances details

NFData FunTyFlag # |
Instance details Defined in GHC.Types.Var Methods rnf :: FunTyFlag -> () #
Data FunTyFlag # |
Instance details Defined in GHC.Types.Var Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> FunTyFlag -> c FunTyFlag # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c FunTyFlag # toConstr :: FunTyFlag -> Constr # dataTypeOf :: FunTyFlag -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c FunTyFlag) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c FunTyFlag) # gmapT :: (forall b. Data b => b -> b) -> FunTyFlag -> FunTyFlag # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> FunTyFlag -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> FunTyFlag -> r # gmapQ :: (forall d. Data d => d -> u) -> FunTyFlag -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> FunTyFlag -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> FunTyFlag -> m FunTyFlag # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> FunTyFlag -> m FunTyFlag # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> FunTyFlag -> m FunTyFlag #
Binary FunTyFlag # |
Instance details Defined in GHC.Types.Var Methods put_ :: WriteBinHandle -> FunTyFlag -> IO () # put :: WriteBinHandle -> FunTyFlag -> IO (Bin FunTyFlag) # get :: ReadBinHandle -> IO FunTyFlag #
Outputable FunTyFlag # |
Instance details Defined in GHC.Types.Var Methods ppr :: FunTyFlag -> SDoc #
Eq FunTyFlag # |
Instance details Defined in GHC.Types.Var Methods (==) :: FunTyFlag -> FunTyFlag -> Bool # (/=) :: FunTyFlag -> FunTyFlag -> Bool #
Ord FunTyFlag # |
Instance details Defined in GHC.Types.Var Methods compare :: FunTyFlag -> FunTyFlag -> Ordering # (<) :: FunTyFlag -> FunTyFlag -> Bool # (<=) :: FunTyFlag -> FunTyFlag -> Bool # (>) :: FunTyFlag -> FunTyFlag -> Bool # (>=) :: FunTyFlag -> FunTyFlag -> Bool # max :: FunTyFlag -> FunTyFlag -> FunTyFlag # min :: FunTyFlag -> FunTyFlag -> FunTyFlag #

mkForAllTy :: ForAllTyBinder -> Type -> Type #

Like `mkTyCoForAllTy`, but does not check the occurrence of the binder See Note [Unused coercion variable in ForAllTy]

mkForAllTys :: [ForAllTyBinder] -> Type -> Type #

Wraps foralls over the type using the provided `TyCoVar`s from left to right

mkInvisForAllTys :: [InvisTVBinder] -> Type -> Type #

Wraps foralls over the type using the provided `InvisTVBinder`s from left to right

mkTyCoInvForAllTys :: [TyCoVar] -> Type -> Type #

Like `mkForAllTys`, but assumes all variables are dependent and `Inferred`, a common case

mkSpecForAllTys :: [TyVar] -> Type -> Type #

Like `mkForAllTys`, but assumes all variables are dependent and `Specified`, a common case

mkTyCoInvForAllTy :: TyCoVar -> Type -> Type #

Make a dependent forall over an `Inferred` variable

mkInfForAllTy :: TyVar -> Type -> Type #

Like `mkTyCoInvForAllTy`, but tv should be a tyvar

mkInfForAllTys :: [TyVar] -> Type -> Type #

Like `mkTyCoInvForAllTys`, but tvs should be a list of tyvar

mkVisFunTy :: HasDebugCallStack => Mult -> Type -> Type -> Type #

mkVisFunTyMany :: HasDebugCallStack => Type -> Type -> Type infixr 3 #

Make nested arrow types | Special, common, case: Arrow type with mult Many

mkVisFunTysMany :: [Type] -> Type -> Type #

mkScaledFunTys :: HasDebugCallStack => [Scaled Type] -> Type -> Type #

mkInvisFunTy :: HasDebugCallStack => Type -> Type -> Type infixr 3 #

mkInvisFunTys :: HasDebugCallStack => [Type] -> Type -> Type #

mkTyConApp :: TyCon -> [Type] -> Type #

A key function: builds a `TyConApp` or `FunTy` as appropriate to its arguments. Applies its arguments to the constructor from left to right.

mkAppTy :: Type -> Type -> Type #

Applies a type to another, as in e.g. `k a`

mkAppTys :: Type -> [Type] -> Type #

mkTyConTy :: TyCon -> Type #

(mkTyConTy tc) returns (TyConApp tc []) but arranges to share that TyConApp among all calls See Note [Sharing nullary TyConApps] So it's just an alias for tyConNullaryTy!

mkTyVarTy :: TyVar -> Type #

mkTyVarTys :: [TyVar] -> [Type] #

mkTyCoVarTy :: TyCoVar -> Type #

mkTyCoVarTys :: [TyCoVar] -> [Type] #

isClassPred :: PredType -> Bool #

isEqPred :: PredType -> Bool #

Does this type classify a core (unlifted) Coercion? At either role nominal or representational (t1 ~# t2) or (t1 ~R# t2) See Note [Types for coercions, predicates, and evidence] in GHC.Core.TyCo.Rep

couldBeIPLike :: Type -> Bool #

isEqClassPred :: PredType -> Bool #

isEqualityClass :: Class -> Bool #

mkClassPred :: Class -> [Type] -> PredType #

tcSplitQuantPredTy :: Type -> ([TyVar], [Type], PredType) #

tcSplitDFunTy :: Type -> ([TyVar], [Type], Class, [Type]) #

tcSplitDFunHead :: Type -> (Class, [Type]) #

tcSplitMethodTy :: Type -> ([TyVar], PredType, Type) #

isRuntimeRepVar :: TyVar -> Bool #

Is a tyvar of type `RuntimeRep`?

isFixedRuntimeRepKind :: HasDebugCallStack => Kind -> Bool #

Checks that a kind of the form `Type`, `Constraint` or `'TYPE r` is concrete. See `isConcreteType`.

Precondition: The type has kind `TYPE blah` or `CONSTRAINT blah`

isVisiblePiTyBinder :: PiTyBinder -> Bool #

Does this binder bind a visible argument?

isInvisiblePiTyBinder :: PiTyBinder -> Bool #

Does this binder bind an invisible argument?

data Subst #

Type & coercion & id substitution

The Subst data type defined in this module contains substitution for tyvar, covar and id. However, operations on IdSubstEnv (mapping from Id to CoreExpr) that require the definition of the Expr data type are defined in GHC.Core.Subst to avoid circular module dependency.

Constructors

Subst InScopeSet IdSubstEnv TvSubstEnv CvSubstEnv |

#### Instances

Instances details

Outputable Subst # |
Instance details Defined in GHC.Core.TyCo.Subst Methods ppr :: Subst -> SDoc #

type TvSubstEnv = TyVarEnv Type #

A substitution of `Type`s for `TyVar`s and `Kind`s for `KindVar`s

emptySubst :: Subst #

mkEmptySubst :: InScopeSet -> Subst #

zipTvSubst :: HasDebugCallStack => [TyVar] -> [Type] -> Subst #

Generates the in-scope set for the `Subst` from the types in the incoming environment. No CoVars or Ids, please!

mkTvSubstPrs :: [(TyVar, Type)] -> Subst #

Generates the in-scope set for the `TCvSubst` from the types in the incoming environment. No CoVars, please! The InScopeSet is just a thunk so with a bit of luck it'll never be evaluated

notElemSubst :: Var -> Subst -> Bool #

unionSubst :: Subst -> Subst -> Subst #

getTvSubstEnv :: Subst -> TvSubstEnv #

substInScopeSet :: Subst -> InScopeSet #

Find the in-scope set: see Note [The substitution invariant]

extendSubstInScope :: Subst -> Var -> Subst #

Add the `Var` to the in-scope set

extendSubstInScopeList :: Subst -> [Var] -> Subst #

Add the `Var`s to the in-scope set: see also `extendInScope`

extendSubstInScopeSet :: Subst -> VarSet -> Subst #

Add the `Var`s to the in-scope set: see also `extendInScope`

extendTvSubstAndInScope :: Subst -> TyVar -> Type -> Subst #

lookupTyVar :: Subst -> TyVar -> Maybe Type #

extendTCvSubst :: Subst -> TyCoVar -> Type -> Subst #

substTyVarBndr :: HasDebugCallStack => Subst -> TyVar -> (Subst, TyVar) #

extendTvSubst :: Subst -> TyVar -> Type -> Subst #

Add a substitution for a `TyVar` to the `Subst` The `TyVar` *must* be a real TyVar, and not a CoVar You must ensure that the in-scope set is such that Note [The substitution invariant] holds after extending the substitution like this.

isInScope :: Var -> Subst -> Bool #

mkTCvSubst :: InScopeSet -> TvSubstEnv -> CvSubstEnv -> Subst #

mkTvSubst :: InScopeSet -> TvSubstEnv -> Subst #

Make a TCvSubst with specified tyvar subst and empty covar subst

zipTyEnv :: HasDebugCallStack => [TyVar] -> [Type] -> TvSubstEnv #

The InScopeSet is just a thunk so with a bit of luck it'll never be evaluated

zipCoEnv :: HasDebugCallStack => [CoVar] -> [Coercion] -> CvSubstEnv #

substTy :: HasDebugCallStack => Subst -> Type -> Type #

Substitute within a `Type` The substitution has to satisfy the invariants described in Note [The substitution invariant].

substTys :: HasDebugCallStack => Subst -> [Type] -> [Type] #

Substitute within several `Type`s The substitution has to satisfy the invariants described in Note [The substitution invariant].

substScaledTys :: HasDebugCallStack => Subst -> [Scaled Type] -> [Scaled Type] #

substTyWith :: HasDebugCallStack => [TyVar] -> [Type] -> Type -> Type #

Type substitution, see `zipTvSubst`

substTyWithCoVars :: [CoVar] -> [Coercion] -> Type -> Type #

Substitute covars within a type

substTyAddInScope :: HasDebugCallStack => Subst -> Type -> Type #

Substitute within a `Type` after adding the free variables of the type to the in-scope set. This is useful for the case when the free variables aren't already in the in-scope set or easily available. See also Note [The substitution invariant].

substTyUnchecked :: Subst -> Type -> Type #

Substitute within a `Type` disabling the sanity checks. The problems that the sanity checks in substTy catch are described in Note [The substitution invariant]. The goal of #11371 is to migrate all the calls of substTyUnchecked to substTy and remove this function. Please don't use in new code.

substTysUnchecked :: Subst -> [Type] -> [Type] #

Substitute within several `Type`s disabling the sanity checks. The problems that the sanity checks in substTys catch are described in Note [The substitution invariant]. The goal of #11371 is to migrate all the calls of substTysUnchecked to substTys and remove this function. Please don't use in new code.

substScaledTyUnchecked :: HasDebugCallStack => Subst -> Scaled Type -> Scaled Type #

substThetaUnchecked :: Subst -> ThetaType -> ThetaType #

Substitute within a `ThetaType` disabling the sanity checks. The problems that the sanity checks in substTys catch are described in Note [The substitution invariant]. The goal of #11371 is to migrate all the calls of substThetaUnchecked to substTheta and remove this function. Please don't use in new code.

substTyWithUnchecked :: [TyVar] -> [Type] -> Type -> Type #

Type substitution, see `zipTvSubst`. Disables sanity checks. The problems that the sanity checks in substTy catch are described in Note [The substitution invariant]. The goal of #11371 is to migrate all the calls of substTyUnchecked to substTy and remove this function. Please don't use in new code.

substCoUnchecked :: Subst -> Coercion -> Coercion #

Substitute within a `Coercion` disabling sanity checks. The problems that the sanity checks in substCo catch are described in Note [The substitution invariant]. The goal of #11371 is to migrate all the calls of substCoUnchecked to substCo and remove this function. Please don't use in new code.

substCoWithUnchecked :: [TyVar] -> [Type] -> Coercion -> Coercion #

Coercion substitution, see `zipTvSubst`. Disables sanity checks. The problems that the sanity checks in substCo catch are described in Note [The substitution invariant]. The goal of #11371 is to migrate all the calls of substCoUnchecked to substCo and remove this function. Please don't use in new code.

substTheta :: HasDebugCallStack => Subst -> ThetaType -> ThetaType #

Substitute within a `ThetaType` The substitution has to satisfy the invariants described in Note [The substitution invariant].

isUnliftedType :: HasDebugCallStack => Type -> Bool #

Is the given type definitely unlifted? See Type for what an unlifted type is.

Panics on representation-polymorphic types; See `mightBeUnliftedType` for a more approximate predicate that behaves better in the presence of representation polymorphism.

isUnboxedTupleType :: Type -> Bool #

isPrimitiveType :: Type -> Bool #

Returns true of types that are opaque to Haskell.

coreView :: Type -> Maybe Type #

This function strips off the top layer only of a type synonym application (if any) its underlying representation type. Returns `Nothing` if there is nothing to look through.

This function does not look through type family applications.

By being non-recursive and inlined, this case analysis gets efficiently joined onto the case analysis that the caller is already doing

tyCoVarsOfType :: Type -> TyCoVarSet #

tyCoVarsOfTypes :: [Type] -> TyCoVarSet #

closeOverKinds :: TyCoVarSet -> TyCoVarSet #

tyCoFVsOfType :: Type -> FV #

The worker for `tyCoFVsOfType` and `tyCoFVsOfTypeList`. The previous implementation used `unionVarSet` which is O(n+m) and can make the function quadratic. It's exported, so that it can be composed with other functions that compute free variables. See Note [FV naming conventions] in GHC.Utils.FV.

Eta-expanded because that makes it run faster (apparently) See Note [FV eta expansion] in GHC.Utils.FV for explanation.

tyCoFVsOfTypes :: [Type] -> FV #

tyCoVarsOfTypeDSet :: Type -> DTyCoVarSet #

`tyCoFVsOfType` that returns free variables of a type in a deterministic set. For explanation of why using `VarSet` is not deterministic see Note [Deterministic FV] in GHC.Utils.FV.

tyCoVarsOfTypesDSet :: [Type] -> DTyCoVarSet #

Returns free variables of types, including kind variables as a deterministic set. For type synonyms it does not expand the synonym.

closeOverKindsDSet :: DTyVarSet -> DTyVarSet #

Add the kind variables free in the kinds of the tyvars in the given set. Returns a deterministic set.

tyCoVarsOfTypeList :: Type -> [TyCoVar] #

`tyCoFVsOfType` that returns free variables of a type in deterministic order. For explanation of why using `VarSet` is not deterministic see Note [Deterministic FV] in GHC.Utils.FV.

tyCoVarsOfTypesList :: [Type] -> [TyCoVar] #

Returns free variables of types, including kind variables as a deterministically ordered list. For type synonyms it does not expand the synonym.

noFreeVarsOfType :: Type -> Bool #

pprKind :: Kind -> SDoc #

pprParendKind :: Kind -> SDoc #

pprSigmaType :: Type -> SDoc #

pprType :: Type -> SDoc #

pprParendType :: Type -> SDoc #

pprTypeApp :: TyCon -> [Type] -> SDoc #

pprTheta :: ThetaType -> SDoc #

pprParendTheta :: ThetaType -> SDoc #

pprThetaArrowTy :: ThetaType -> SDoc #

pprClassPred :: Class -> [Type] -> SDoc #

pprTCvBndr :: ForAllTyBinder -> SDoc #

pprTCvBndrs :: [ForAllTyBinder] -> SDoc #

tyConVisibilities :: TyCon -> [Bool] #

For every arg a tycon can take, the returned list says True if the argument is taken visibly, and False otherwise. Ends with an infinite tail of Trues to allow for oversaturation.

isNextTyConArgVisible :: TyCon -> [Type] -> Bool #

If the tycon is applied to the types, is the next argument visible?

isNextArgVisible :: TcType -> Bool #

Should this type be applied to a visible argument? E.g. (s t): is `t` a visible argument of `s`?