Safe Haskell	None
Language	GHC2021

GHC.Core.Predicate

Contents

Well-scoped free variables

Synopsis

data Pred
- = ClassPred Class [Type]
- | EqPred EqRel Type Type
- | IrredPred PredType
- | ForAllPred [TyVar] [PredType] PredType
classifyPredType :: PredType -> Pred
isPredTy :: HasDebugCallStack => Type -> Bool
isEvVarType :: Type -> Bool
data EqRel
- = NomEq
- | ReprEq
eqRelRole :: EqRel -> Role
isEqPred :: PredType -> Bool
isReprEqPred :: PredType -> Bool
isEqClassPred :: PredType -> Bool
isCoVarType :: Type -> Bool
getEqPredTys :: PredType -> (Type, Type)
getEqPredTys_maybe :: PredType -> Maybe (Role, Type, Type)
getEqPredRole :: PredType -> Role
predTypeEqRel :: PredType -> EqRel
mkNomEqPred :: Type -> Type -> Type
mkReprEqPred :: Type -> Type -> Type
mkEqPred :: EqRel -> Type -> Type -> PredType
mkEqPredRole :: Role -> Type -> Type -> PredType
mkClassPred :: Class -> [Type] -> PredType
isDictTy :: Type -> Bool
typeDeterminesValue :: Type -> Bool
isClassPred :: PredType -> Bool
isEqualityClass :: Class -> Bool
isCTupleClass :: Class -> Bool
getClassPredTys :: HasDebugCallStack => PredType -> (Class, [Type])
getClassPredTys_maybe :: PredType -> Maybe (Class, [Type])
classMethodTy :: Id -> Type
classMethodInstTy :: Id -> [Type] -> Type
isIPLikePred :: Type -> Bool
mentionsIP :: (Type -> Bool) -> (Type -> Bool) -> Class -> [Type] -> Bool
isIPTyCon :: TyCon -> Bool
isIPClass :: Class -> Bool
isCallStackTy :: Type -> Bool
isCallStackPred :: Class -> [Type] -> Maybe FastString
isCallStackPredTy :: Type -> Bool
isExceptionContextPred :: Class -> [Type] -> Maybe FastString
isExceptionContextTy :: Type -> Bool
isIPPred_maybe :: Class -> [Type] -> Maybe (Type, Type)
type DictId = EvId
isEvVar :: Var -> Bool
isDictId :: Id -> Bool
scopedSort :: [Var] -> [Var]
tyCoVarsOfTypeWellScoped :: Type -> [TyVar]
tyCoVarsOfTypesWellScoped :: [Type] -> [TyVar]
data CanEqLHS
- = TyVarLHS TyVar
- | TyFamLHS TyCon [Type]
canEqLHS_maybe :: Type -> Maybe CanEqLHS
canTyFamEqLHS_maybe :: Type -> Maybe CanEqLHS
canEqLHSKind :: CanEqLHS -> Kind
canEqLHSType :: CanEqLHS -> Type
eqCanEqLHS :: CanEqLHS -> CanEqLHS -> Bool

Documentation

data Pred Source #

A predicate in the solver. The solver tries to prove Wanted predicates from Given ones.

Constructors

ClassPred Class [Type]	A typeclass predicate.
EqPred EqRel Type Type	A type equality predicate, (t1 ~#N t2) or (t1 ~#R t2)
IrredPred PredType	An irreducible predicate.
ForAllPred [TyVar] [PredType] PredType	A quantified predicate. See Note [Quantified constraints] in GHC.Tc.Solver.Solve

classifyPredType :: PredType -> Pred Source #

isPredTy :: HasDebugCallStack => Type -> Bool Source #

isEvVarType :: Type -> Bool Source #

data EqRel Source #

A choice of equality relation. This is separate from the type Role because Phantom does not define a (non-trivial) equality relation.

Constructors

NomEq
ReprEq

Instances

Instances details

Outputable EqRel Source #
Instance details Defined in GHC.Core.Predicate Methods ppr :: EqRel -> SDoc Source #
Eq EqRel Source #
Instance details Defined in GHC.Core.Predicate Methods (==) :: EqRel -> EqRel -> Bool # (/=) :: EqRel -> EqRel -> Bool #
Ord EqRel Source #
Instance details Defined in GHC.Core.Predicate Methods compare :: EqRel -> EqRel -> Ordering # (<) :: EqRel -> EqRel -> Bool # (<=) :: EqRel -> EqRel -> Bool # (>) :: EqRel -> EqRel -> Bool # (>=) :: EqRel -> EqRel -> Bool # max :: EqRel -> EqRel -> EqRel # min :: EqRel -> EqRel -> EqRel #

eqRelRole :: EqRel -> Role Source #

isEqPred :: PredType -> Bool Source #

isReprEqPred :: PredType -> Bool Source #

isEqClassPred :: PredType -> Bool Source #

isCoVarType :: Type -> Bool Source #

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

getEqPredTys :: PredType -> (Type, Type) Source #

getEqPredTys_maybe :: PredType -> Maybe (Role, Type, Type) Source #

getEqPredRole :: PredType -> Role Source #

predTypeEqRel :: PredType -> EqRel Source #

Get the equality relation relevant for a pred type Returns NomEq for dictionary predicates, etc

mkNomEqPred :: Type -> Type -> Type Source #

Creates a primitive nominal type equality predicate. t1 ~# t2 Invariant: the types are not Coercions

mkReprEqPred :: Type -> Type -> Type Source #

Creates a primitive representational type equality predicate. t1 ~R# t2 Invariant: the types are not Coercions

mkEqPred :: EqRel -> Type -> Type -> PredType Source #

Makes a lifted equality predicate at the given role

mkEqPredRole :: Role -> Type -> Type -> PredType Source #

Makes a lifted equality predicate at the given role

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

isDictTy :: Type -> Bool Source #

typeDeterminesValue :: Type -> Bool Source #

isClassPred :: PredType -> Bool Source #

isEqualityClass :: Class -> Bool Source #

isCTupleClass :: Class -> Bool Source #

getClassPredTys :: HasDebugCallStack => PredType -> (Class, [Type]) Source #

getClassPredTys_maybe :: PredType -> Maybe (Class, [Type]) Source #

classMethodTy :: Id -> Type Source #

classMethodInstTy :: Id -> [Type] -> Type Source #

isIPLikePred :: Type -> Bool Source #

mentionsIP Source #

Arguments

:: (Type -> Bool)	predicate on the string
-> (Type -> Bool)	predicate on the type
-> Class
-> [Type]
-> Bool

mentionsIP str_cond ty_cond cls tys returns True if:

cls tys is of the form IP str ty, where str_cond str and ty_cond ty are both True,
or any superclass of cls tys has this property.

See Note [Local implicit parameters]

isIPTyCon :: TyCon -> Bool Source #

isIPClass :: Class -> Bool Source #

isCallStackTy :: Type -> Bool Source #

Is a type a CallStack?

isCallStackPred :: Class -> [Type] -> Maybe FastString Source #

Is a PredType a CallStack implicit parameter?

If so, return the name of the parameter.

isCallStackPredTy :: Type -> Bool Source #

isExceptionContextPred :: Class -> [Type] -> Maybe FastString Source #

Is a PredType an ExceptionContext implicit parameter?

If so, return the name of the parameter.

isExceptionContextTy :: Type -> Bool Source #

Is a type an ExceptionContext?

isIPPred_maybe :: Class -> [Type] -> Maybe (Type, Type) Source #

Decomposes a predicate if it is an implicit parameter. Does not look in superclasses. See also [Local implicit parameters].

type DictId = EvId Source #

Dictionary Identifier

isEvVar :: Var -> Bool Source #

isDictId :: Id -> Bool Source #

Well-scoped free variables

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

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

tyCoVarsOfTypeWellScoped :: Type -> [TyVar] Source #

Get the free vars of a type in scoped order

tyCoVarsOfTypesWellScoped :: [Type] -> [TyVar] Source #

Get the free vars of types in scoped order

data CanEqLHS Source #

A CanEqLHS is a type that can appear on the left of a canonical equality: a type variable or exactly-saturated type family application.

Constructors

TyVarLHS TyVar
TyFamLHS
Fields TyCon TyCon of the family [Type] Arguments, exactly saturating the family

Instances

Instances details

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

canEqLHS_maybe :: Type -> Maybe CanEqLHS Source #

Is a type a canonical LHS? That is, is it a tyvar or an exactly-saturated type family application? Does not look through type synonyms.

canTyFamEqLHS_maybe :: Type -> Maybe CanEqLHS Source #

canEqLHSKind :: CanEqLHS -> Kind Source #

Retrieve the kind of a CanEqLHS

canEqLHSType :: CanEqLHS -> Type Source #

Convert a CanEqLHS back into a Type

eqCanEqLHS :: CanEqLHS -> CanEqLHS -> Bool Source #

Are two CanEqLHSs equal?