Safe Haskell	None
Language	Haskell2010

GHC.Core.Predicate

Synopsis

data Pred
- = ClassPred Class [Type]
- | EqPred EqRel Type Type
- | IrredPred PredType
- | ForAllPred [TyVar] [PredType] PredType
- | SpecialPred SpecialPred Type
classifyPredType :: PredType -> Pred
isPredTy :: HasDebugCallStack => Type -> Bool
isEvVarType :: Type -> Bool
data EqRel
- = NomEq
- | ReprEq
eqRelRole :: EqRel -> Role
isEqPrimPred :: PredType -> Bool
isEqPred :: PredType -> Bool
getEqPredTys :: PredType -> (Type, Type)
getEqPredTys_maybe :: PredType -> Maybe (Role, Type, Type)
getEqPredRole :: PredType -> Role
predTypeEqRel :: PredType -> EqRel
mkPrimEqPred :: Type -> Type -> Type
mkReprPrimEqPred :: Type -> Type -> Type
mkPrimEqPredRole :: Role -> Type -> Type -> PredType
mkHeteroPrimEqPred :: Kind -> Kind -> Type -> Type -> Type
mkHeteroReprPrimEqPred :: Kind -> Kind -> Type -> Type -> Type
data SpecialPred = ConcretePrimPred
specialPredTyCon :: SpecialPred -> TyCon
mkClassPred :: Class -> [Type] -> PredType
isDictTy :: Type -> Bool
isClassPred :: PredType -> Bool
isEqPredClass :: 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
hasIPSuperClasses :: Class -> [Type] -> Bool
isIPTyCon :: TyCon -> Bool
isIPClass :: Class -> Bool
isCallStackTy :: Type -> Bool
isCallStackPred :: Class -> [Type] -> Maybe FastString
isCallStackPredTy :: Type -> Bool
type DictId = EvId
isEvVar :: Var -> Bool
isDictId :: Id -> 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.
IrredPred PredType	An irreducible predicate.
ForAllPred [TyVar] [PredType] PredType	A quantified predicate. See Note [Quantified constraints] in GHC.Tc.Solver.Canonical
SpecialPred SpecialPred Type	A special predicate, used internally in GHC. The meaning of the type argument is dictated by the `SpecialPred` specified in the first agument; see the documentation of `SpecialPred` for more info. Example: `Concrete# rep`, used for representation-polymorphism checks within GHC. See Note [The Concrete mechanism] in GHC.Tc.Utils.Concrete. (This is the only example currently. More to come: see GHC ticket #20000.)

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

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

eqRelRole :: EqRel -> Role Source #

isEqPrimPred :: PredType -> Bool Source #

isEqPred :: PredType -> Bool Source #

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.

mkPrimEqPred :: Type -> Type -> Type Source #

Creates a primitive type equality predicate. Invariant: the types are not Coercions

mkReprPrimEqPred :: Type -> Type -> Type Source #

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

Makes a lifted equality predicate at the given role

mkHeteroPrimEqPred :: Kind -> Kind -> Type -> Type -> Type Source #

Creates a primitive type equality predicate with explicit kinds

mkHeteroReprPrimEqPred :: Kind -> Kind -> Type -> Type -> Type Source #

Creates a primitive representational type equality predicate with explicit kinds

data SpecialPred Source #

SpecialPred describes all the special predicates that are currently used in GHC.

These are different from the special typeclasses (such as KnownNat, Typeable, Coercible, ...), as special predicates can't be expressed as typeclasses, as they hold evidence of a different kind.

Constructors

ConcretePrimPred

A Concrete# predicate, to check for representation polymorphism.

When the first argument to the SpecialPred data constructor of Pred is ConcretePrimPred, the second argument is the type we are inspecting to decide whether it is concrete. That is, it refers to the second argument of the 'Concrete#' TyCon. Recall that this TyCon has kind

forall k. k -> TupleRep '[]

See Note [The Concrete mechanism] in GHC.Tc.Utils.Concrete for further details.

Instances

Instances details

Eq SpecialPred Source #
Instance details Defined in GHC.Core.Predicate Methods (==) :: SpecialPred -> SpecialPred -> Bool # (/=) :: SpecialPred -> SpecialPred -> Bool #
Outputable SpecialPred Source #
Instance details Defined in GHC.Core.Predicate Methods ppr :: SpecialPred -> SDoc Source #