GHC.Tc.Types.Constraint · ghc-10.0.0.20260917

typetype Xi = TcType

A Xi-type is one that has been fully rewritten with respect to the inert set; that is, it has been rewritten by the algorithm in GHC.Tc.Solver.Rewrite. (Historical note: Xi, for years and years, meant that a type was type-family-free. It does *not* mean this any more.)

datadata Ct

#

Constraint

Constructors

CDictCan DictCt
A dictionary constraint (canonical)
CIrredCan IrredCt
An irreducible constraint (non-canonical)
CEqCan EqCt
An equality constraint (canonical)
CQuantCan QCInst
A quantified constraint (canonical)
CNonCanonical CtEvidence
A non-canonical constraint
See Note [NonCanonical Semantics] in GHC.Tc.Solver.Monad

Instances1Outputable

Outputable CtDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

typetype Cts = Bag Ct

#

valuesingleCt :: Ct -> Cts

#

valuelistToCts :: [Ct] -> Cts

#

valuectsElts :: Cts -> [Ct]

#

valueconsCts :: Ct -> Cts -> Cts

#

valuesnocCts :: Cts -> Ct -> Cts

#

valueextendCtsList :: Cts -> [Ct] -> Cts

#

valueisEmptyCts :: Cts -> Bool

#

valueemptyCts :: Cts

#

valueandCts :: Cts -> Cts -> Cts

#

valuectsPreds :: Cts -> [PredType]

#

valueisPendingScDictCt :: DictCt -> Bool

#

valueisPendingScDict :: Ct -> Bool

#

valuependingScDict_maybe :: Ct -> Maybe Ct

#

valuesuperClassesMightHelp :: WantedConstraints -> Bool

#

True if taking superclasses of givens, or of wanteds (to perhaps expose more equalities or functional dependencies) might help to solve this constraint. See Note [When superclasses help]

valuegetPendingWantedScs :: Cts -> ([Ct], Cts)

#

valueisWantedCt :: Ct -> Bool

#

valueisGivenCt :: Ct -> Bool

#

valueuserTypeError_maybe

:: Bool
Look everywhere: inside type-family applications, class constraints, AppTys etc?
-> Type
-> Maybe ErrorMsgType

#

Does this type contain 'TypeError msg', either at the top-level or nested within it somewhere?

If so, return the error message.

See Note [Custom type errors in constraints].

valuecontainsUserTypeError

:: Bool
look inside type-family applications, AppTy, etc?
-> PredType
-> Bool

#

Does this constraint contain an user error message?

That is, the type is either of the form Unsatisfiable err, or it contains a type of the form TypeError msg, either at the top level or nested inside the type.

See Note [Custom type errors in constraints].

valueisUnsatisfiableCt_maybe :: Type -> Maybe ErrorMsgType

#

Is this type an unsatisfiable constraint? If so, return the error message.

valuectEvidence :: Ct -> CtEvidence

#

valueupdCtEvidence :: (CtEvidence -> CtEvidence) -> Ct -> Ct

#

valuectLoc :: Ct -> CtLoc

#

valuectPred :: Ct -> PredType

#

valuectFlavour :: Ct -> CtFlavour

#

Get the flavour of the given Ct

valuectEqRel :: Ct -> EqRel

#

Get the equality relation for the given Ct

valuectOrigin :: Ct -> CtOrigin

#

valuectRewriters :: Ct -> CoHoleSet

#

valuectHasNoRewriters :: Ct -> Bool

#

valuewantedCtHasNoRewriters :: WantedCtEvidence -> Bool

#

valuectEvId :: HasDebugCallStack => Ct -> EvVar

#

valuewantedEvId_maybe :: Ct -> Maybe EvVar

#

Returns the evidence Id for the argument Ct when this Ct is a Wanted.

Returns Nothing otherwise.

valuemkTcEqPredLikeEv :: CtEvidence -> TcType -> TcType -> TcType

#

Makes a new equality predicate with the same role as the given evidence.

valuemkNonCanonical :: CtEvidence -> Ct

#

valuemkGivens :: CtLoc -> [EvId] -> [Ct]

#

valuetyCoVarsOfCt :: Ct -> TcTyCoVarSet

#

Returns free variables of constraints as a non-deterministic set This must consult only the ctPred, so that it gets *tidied* fvs if the constraint has been tidied. Tidying a constraint does not tidy the fields of the Ct, only the predicate in the CtEvidence.

valuetyCoVarsOfCts :: Cts -> TcTyCoVarSet

#

Returns free variables of a bag of constraints as a non-deterministic set. See Note [Deterministic FV] in GHC.Utils.FV.

valuetyCoVarsOfCtList :: Ct -> [TcTyCoVar]

#

Returns free variables of constraints as a deterministically ordered list. See Note [Deterministic FV] in GHC.Utils.FV.

valuetyCoVarsOfCtsList :: Cts -> [TcTyCoVar]

#

Returns free variables of a bag of constraints as a deterministically ordered list. See Note [Deterministic FV] in GHC.Types.Var.FV.

valueboundOccNamesOfWC :: WantedConstraints -> [OccName]

#

datadata EqCt

#

A canonical equality constraint.

See Note [Canonical equalities] in GHC.Tc.Types.Constraint.

Constructors

EqCt
- eq_ev :: CtEvidence
- eq_lhs :: CanEqLHS
- eq_rhs :: Xi
- eq_eq_rel :: EqRel

Instances1Outputable

Outputable EqCtDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

valueeqCtEvidence :: EqCt -> CtEvidence

#

valueeqCtLHS :: EqCt -> CanEqLHS

#

datadata DictCt

#

A canonical dictionary constraint

Constructors

DictCt
- di_ev :: CtEvidence
- di_cls :: Class
- di_tys :: [Xi]
- di_pend_sc :: ExpansionFuel

Instances1Outputable

Outputable DictCtDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

valuedictCtEvidence :: DictCt -> CtEvidence

#

valuedictCtPred :: DictCt -> TcPredType

#

datadata IrredCt

#

Constructors

IrredCt
- ir_ev :: CtEvidence
- ir_reason :: CtIrredReason

Instances1Outputable

Outputable IrredCtDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

valueirredCtEvidence :: IrredCt -> CtEvidence

#

valuemkIrredCt :: CtIrredReason -> CtEvidence -> Ct

#

valuectIrredCt :: CtIrredReason -> Ct -> IrredCt

#

valueirredCtPred :: IrredCt -> PredType

#

datadata QCInst

#

A quantified constraint, also called a "local instance" (a simplified version of ClsInst).

See Note [Quantified constraints] in GHC.Tc.Solver.Solve

Constructors

QCI
A quantified constraint, of type forall tvs. context => ty
- qci_ev :: CtEvidence
- qci_tvs :: [TcTyVar]
```
tvs
```
- qci_theta :: TcThetaType
- qci_body :: TcPredType
  the body of the forall, i.e. ty
- qci_pend_sc :: ExpansionFuel
  Invariants: qci_pend_sc > 0 =>
  (a) qci_body is a ClassPred (b) this class has superclass(es), and (c) the superclass(es) are not explored yet
  Same as di_pend_sc flag in DictCt See Note [Expanding Recursive Superclasses and ExpansionFuel] in GHC.Tc.Solver

Instances1Outputable

Outputable QCInstDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

valuependingScInst_maybe :: QCInst -> Maybe QCInst

#

typetype ExpansionFuel = Int

#

Says how many layers of superclasses can we expand. Invariant: ExpansionFuel should always be >= 0 see Note [Expanding Recursive Superclasses and ExpansionFuel]

valuedoNotExpand :: ExpansionFuel

#

Do not expand superclasses any further

valueconsumeFuel :: ExpansionFuel -> ExpansionFuel

#

Consumes one unit of fuel. Precondition: fuel > 0

valuependingFuel :: ExpansionFuel -> Bool

#

Returns True if we have any fuel left for superclass expansion

valueassertFuelPrecondition :: ExpansionFuel -> a -> a

#

asserts if fuel is non-negative

valueassertFuelPreconditionStrict :: ExpansionFuel -> a -> a

#

asserts if fuel is strictly greater than 0

datadata CtIrredReason

#

Used to indicate extra information about why a CIrredCan is irreducible

Constructors

IrredShapeReason
This constraint has a non-canonical shape (e.g. c Int, for a variable c)
NonCanonicalReason CheckTyEqResult
An equality where some invariant other than (TyEq:H) of CEqCan is not satisfied; the CheckTyEqResult states exactly why
ReprEqReason
An equality that cannot be decomposed because it is representational. Example: a b ~R# Int. These might still be solved later. INVARIANT: The constraint is a representational equality constraint
ShapeMismatchReason
A nominal equality that relates two wholly different types, like Int ~# Bool or a b ~# 3. INVARIANT: The constraint is a nominal equality constraint
AbstractTyConReason
An equality like T a b c ~ Q d e where either T or Q is an abstract type constructor. See Note [Skolem abstract data] in GHC.Core.TyCon. INVARIANT: The constraint is an equality constraint between two TyConApps
PluginReason
A typechecker plugin returned this in the pluginBadCts field of TcPluginProgress
InsolubleFunDepReason Bool
This constraint generated a functional dependency that is insoluble -- so we can regard this constraint too as insoluble See Note [Insoluble fundeps] in GHC.Tc.Solver.FunDeps
Bool = True = insolubility arises from top-level constraints only See (IFD2) in the Note [Insoluble fundeps]

Instances1Outputable

Outputable CtIrredReasonDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

valueisInsolubleReason :: CtIrredReason -> Bool

#

Are we sure that more solving will never solve this constraint?

newtypenewtype CheckTyEqResult

#

A set of problems in checking the validity of a type equality. See checkTypeEq.

Instances3Semigroup, Monoid, Outputable

Semigroup CheckTyEqResultDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint
Monoid CheckTyEqResultDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint
Outputable CheckTyEqResultDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

newtypenewtype CheckTyEqProblem

#

An individual problem that might be logged in a CheckTyEqResult

Instances2Eq, Outputable

Eq CheckTyEqProblemDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint
Outputable CheckTyEqProblemDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

valuecteProblem :: CheckTyEqProblem -> CheckTyEqResult

#

valuecterClearOccursCheck :: CheckTyEqResult -> CheckTyEqResult

#

valuecteOK :: CheckTyEqResult

#

No problems in checking the validity of a type equality.

valuecteImpredicative :: CheckTyEqProblem

#

valuecteTypeFamily :: CheckTyEqProblem

#

valuecteInsolubleOccurs :: CheckTyEqProblem

#

valuecteSolubleOccurs :: CheckTyEqProblem

#

valuecterSetOccursCheckSoluble :: CheckTyEqResult -> CheckTyEqResult

#

Mark a CheckTyEqResult as not having an insoluble occurs-check: any occurs check under a type family or in a representation equality is soluble.

valuecteConcrete :: CheckTyEqProblem

#

valuecteSkolemEscape :: CheckTyEqProblem

#

valueimpredicativeProblem :: CheckTyEqResult

#

valueinsolubleOccursProblem :: CheckTyEqResult

#

valuesolubleOccursProblem :: CheckTyEqResult

#

valuecterHasNoProblem :: CheckTyEqResult -> Bool

#

Check whether a CheckTyEqResult is marked successful.

valuecterHasProblem :: CheckTyEqResult -> CheckTyEqProblem -> Bool

#

Check whether a CheckTyEqResult has a CheckTyEqProblem

valuecterHasOnlyProblem :: CheckTyEqResult -> CheckTyEqProblem -> Bool

#

Check whether a CheckTyEqResult has one CheckTyEqProblem and no other

valuecterHasOnlyProblems :: CheckTyEqResult -> CheckTyEqResult -> Bool

#

valuecterRemoveProblem :: CheckTyEqResult -> CheckTyEqProblem -> CheckTyEqResult

#

valuecterHasOccursCheck :: CheckTyEqResult -> Bool

#

valuecterFromKind :: CheckTyEqResult -> CheckTyEqResult

#

Retain only information about occurs-check failures, because only that matters after recurring into a kind.

datadata CanEqLHS

#

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 TyCon [Type]

Instances1Outputable

Outputable CanEqLHSDefined in ghc-10.0.0.20260917 · GHC.Core.Predicate

valuecanEqLHS_maybe :: Type -> Maybe CanEqLHS

#

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.

valuecanTyFamEqLHS_maybe :: Type -> Maybe CanEqLHS

#

valuecanEqLHSKind :: CanEqLHS -> Kind

#

Retrieve the kind of a CanEqLHS

valuecanEqLHSType :: CanEqLHS -> Type

#

Convert a CanEqLHS back into a Type

valueeqCanEqLHS :: CanEqLHS -> CanEqLHS -> Bool

#

Are two CanEqLHSs equal?

datadata Hole

#

A hole stores the information needed to report diagnostics about holes in terms (unbound identifiers or underscores) or in types (also called wildcards, as used in partial type signatures). See Note [Holes in expressions] for holes in terms.

Constructors

Hole
- hole_sort :: HoleSort
  What flavour of hole is this?
- hole_occ :: RdrName
  The name of this hole
- hole_ty :: TcType
  Type to be printed to the user For expression holes: type of expr For type holes: the missing type
- hole_loc :: CtLoc
  Where hole was written

Instances1Outputable

Outputable HoleDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

datadata HoleSort

#

Used to indicate which sort of hole we have.

Constructors

ExprHole HoleExprRef
Either an out-of-scope variable or a "true" hole in an expression (TypedHoles). The HoleExprRef says where to write the the erroring expression for -fdefer-type-errors.
TypeHole
A hole in a type (PartialTypeSignatures)
ConstraintHole
A hole in a constraint, like @f :: (_, Eq a) => ... Differentiated from TypeHole because a ConstraintHole is simplified differently. See Note [Do not simplify ConstraintHoles] in GHC.Tc.Solver.

Instances1Outputable

Outputable HoleSortDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

valueisOutOfScopeHole :: Hole -> Bool

#

Does this hole represent an "out of scope" error?

See Note [Insoluble holes]

datadata DelayedError

#

A delayed error, to be reported after constraint solving, in order to benefit from deferred unifications.

Constructors

DE_Hole Hole
A hole (in a type or in a term).
See Note [Holes in expressions].
DE_NotConcrete NotConcreteError
A type could not be ensured to be concrete.
See Note [The Concrete mechanism] in GHC.Tc.Utils.Concrete.
DE_Multiplicity TcCoercion CtLoc
An error if the TcCoercion isn't a reflexivity constraint.
See Note [Coercion errors in tcSubMult] in GHC.Tc.Utils.Unify.

Instances1Outputable

Outputable DelayedErrorDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

datadata NotConcreteError

#

Why did we require that a certain type be concrete?

Constructors

NCE_FRR
Concreteness was required by a representation-polymorphism check.
See Note [The Concrete mechanism] in GHC.Tc.Utils.Concrete.
- nce_loc :: CtLoc
  Where did this check take place?
- nce_frr_origin :: FixedRuntimeRepOrigin
  Which representation-polymorphism check did we perform?

Instances1Outputable

Outputable NotConcreteErrorDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

datadata WantedConstraints

#

Constructors

WC
- wc_simple :: Cts
- wc_impl :: Bag Implication
- wc_errors :: Bag DelayedError

Instances3Semigroup, Monoid, Outputable

Semigroup WantedConstraintsDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint
Monoid WantedConstraintsDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint
Outputable WantedConstraintsDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

valueinsolubleWC :: WantedConstraints -> Bool

#

valueemptyWC :: WantedConstraints

#

valueisEmptyWC :: WantedConstraints -> Bool

#

isEmptyWC sees if a WantedConstraints is truly empty, including having no implications.

It's possible that it might have solved implications, which are left around just so we can report unreachable code. So: isEmptyWC implies isSolvedWC but not vice versa

valueisSolvedWC :: WantedConstraints -> Bool

#

Checks whether a the given wanted constraints are solved, i.e. that there are no simple constraints left and all the implications are solved.

valueandWC :: WantedConstraints -> WantedConstraints -> WantedConstraints

#

valueunionsWC :: [WantedConstraints] -> WantedConstraints

#

valuemkSimpleWC :: [CtEvidence] -> WantedConstraints

#

valuemkImplicWC :: Bag Implication -> WantedConstraints

#

valueaddInsols :: WantedConstraints -> Bag IrredCt -> WantedConstraints

#

valuedropMisleading :: WantedConstraints -> WantedConstraints

#

valueaddSimples :: WantedConstraints -> Bag Ct -> WantedConstraints

#

valueaddImplics :: WantedConstraints -> Bag Implication -> WantedConstraints

#

valueaddHoles :: WantedConstraints -> Bag Hole -> WantedConstraints

#

valueaddNotConcreteError

:: WantedConstraints
-> NotConcreteError
-> WantedConstraints

#

valueaddMultiplicityCoercionError

:: WantedConstraints
-> TcCoercion
-> CtLoc
-> WantedConstraints

#

valueaddDelayedErrors

:: WantedConstraints
-> Bag DelayedError
-> WantedConstraints

#

valuetyCoVarsOfWC :: WantedConstraints -> TyCoVarSet

#

Returns free variables of WantedConstraints as a non-deterministic set. See Note [Deterministic FV] in GHC.Types.Var.FV.

valuetyCoVarsOfWCList :: WantedConstraints -> [TyCoVar]

#

Returns free variables of WantedConstraints as a deterministically ordered list. See Note [Deterministic FV] in GHC.Types.Var.FV.

valueinsolubleWantedCt :: Ct -> Bool

#

Is this a definitely insoluble Wanted constraint? Namely:

a Wanted,
which is insoluble (as per insolubleCt),
that does not arise from a Given or a Wanted/Wanted fundep interaction.

See Note [Insoluble Wanteds]

valueinsolubleCt :: Ct -> Bool

#

Returns True of constraints that are definitely insoluble, including constraints that include custom type errors, as per (1) in Note [Custom type errors in constraints].

Can return True for Given constraints, unlike insolubleWantedCt.

valueinsolubleImplic :: Implication -> Bool

#

valuenonDefaultableTyVarsOfWC :: WantedConstraints -> TyCoVarSet

#

Gather all the type variables from WantedConstraints that it would be unhelpful to default. For the moment, these are only ConcreteTv metavariables participating in a nominal equality whose other side is not concrete; it's usually better to report those as errors instead of defaulting.

valueapproximateWCX :: Bool -> WantedConstraints -> ApproxWC

#

valueapproximateWC :: Bool -> WantedConstraints -> Bag Ct

#

datadata Implication

#

Constructors

Implic
- ic_tclvl :: TcLevel
- ic_info :: SkolemInfoAnon
- ic_skols :: [TcTyVar]
- ic_given :: [EvVar]
- ic_given_eqs :: HasGivenEqs
- ic_warn_inaccessible :: Bool
- ic_env :: !CtLocEnv
- ic_wanted :: WantedConstraints
- ic_binds :: EvBindsVar
- ic_status :: ImplicStatus

Instances1Outputable

Outputable ImplicationDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

valueimplicationPrototype :: CtLocEnv -> Implication

#

valuecheckTelescopeSkol :: SkolemInfoAnon -> Bool

#

datadata ImplicStatus

#

Constructors

IC_Solved
- ics_dead :: [EvVar]
- ics_dm :: NeededEvIds
- ics_non_dm :: NeededEvIds
IC_Insoluble
IC_BadTelescope
IC_Unsolved

Instances1Outputable

Outputable ImplicStatusDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

valueisInsolubleStatus :: ImplicStatus -> Bool

#

valueisSolvedStatus :: ImplicStatus -> Bool

#

typetype UserGiven = Implication

#

valuegetGivensFromImplics :: [Implication] -> [UserGiven]

#

datadata HasGivenEqs

#

NoGivenEqs LocalGivenEqs MaybeGivenEqs

Instances4Eq, Semigroup, Monoid, Outputable

Eq HasGivenEqsDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint
Semigroup HasGivenEqsDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint
Monoid HasGivenEqsDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint
Outputable HasGivenEqsDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

valuecheckImplicationInvariants

:: (HasCallStack, Applicative m)
=> Implication
-> m ()

#

datadata CtLocEnv

#

Local typechecker environment for a constraint.

Used to restore the environment of a constraint when reporting errors, see setCtLocM.

Constructors

CtLocEnv
- ctl_ctxt :: !ErrCtxtStack
- ctl_loc :: !RealSrcSpan
- ctl_bndrs :: !TcBinderStack
- ctl_tclvl :: !TcLevel
- ctl_in_gen_code :: !Bool
- ctl_rdr :: !LocalRdrEnv

valuesetCtLocEnvLoc :: CtLocEnv -> SrcSpan -> CtLocEnv

#

valuesetCtLocEnvLvl :: CtLocEnv -> TcLevel -> CtLocEnv

#

valuegetCtLocEnvLoc :: CtLocEnv -> RealSrcSpan

#

valuegetCtLocEnvLvl :: CtLocEnv -> TcLevel

#

valuectLocEnvInGeneratedCode :: CtLocEnv -> Bool

#

datadata CtEvidence

#

Instances1Outputable

Outputable CtEvidenceDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

datadata TcEvDest

#

A place for type-checking evidence to go after it is generated.

Wanted equalities use HoleDest,
other Wanteds use EvVarDest.

Constructors

EvVarDest EvVar
bind this var to the evidence EvVarDest is always used for non-type-equalities e.g. class constraints
HoleDest CoercionHole
fill in this hole with the evidence HoleDest is always used for type-equalities See Note [Coercion holes] in GHC.Core.TyCo.Rep

Instances1Outputable

Outputable TcEvDestDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

valueisWanted :: CtEvidence -> Bool

#

valueisGiven :: CtEvidence -> Bool

#

valuectEvPred :: CtEvidence -> TcPredType

#

valuectEvLoc :: CtEvidence -> CtLoc

#

valuectEvOrigin :: CtEvidence -> CtOrigin

#

valuectEvEqRel :: HasDebugCallStack => CtEvidence -> EqRel

#

Get the equality relation relevant for a CtEvidence

valuectEvExpr :: HasDebugCallStack => CtEvidence -> EvExpr

#

valuectEvTerm :: CtEvidence -> EvTerm

#

valuectEvCoercion :: HasDebugCallStack => CtEvidence -> TcCoercion

#

valuewantedCtEvCoercion :: HasDebugCallStack => WantedCtEvidence -> TcCoercion

#

valuegivenCtEvCoercion :: HasDebugCallStack => GivenCtEvidence -> TcCoercion

#

valuectEvEvId :: CtEvidence -> EvVar

#

valuewantedCtEvEvId :: WantedCtEvidence -> EvVar

#

valuectEvRewriters :: CtEvidence -> CoHoleSet

#

Extract the set of rewriters from a CtEvidence See Note [Wanteds rewrite Wanteds: rewriter-sets] If the provided CtEvidence is not for a Wanted, just return an empty set.

valuectEvCoHoleSet :: CtEvidence -> CoHoleSet

#

valuesetWantedCtEvRewriters :: WantedCtEvidence -> CoHoleSet -> WantedCtEvidence

#

Set the rewriter set of a Wanted constraint.

valuectEvUnique :: CtEvidence -> Unique

#

valuetcEvDestUnique :: TcEvDest -> Unique

#

valuectEvRewriteRole :: HasDebugCallStack => CtEvidence -> Role

#

Get the rewrite-role relevant for a CtEvidence See Note [The rewrite-role of a constraint]

valuectEvRewriteEqRel :: CtEvidence -> EqRel

#

Return the rewrite-role of an abitrary CtEvidence See Note [The rewrite-role of a constraint] We return ReprEq for (a ~R# b) and NomEq for all other preds

valuesetCtEvPredType :: HasDebugCallStack => CtEvidence -> Type -> CtEvidence

#

Set the type of CtEvidence.

This function ensures that the invariants on CtEvidence hold, by updating the evidence and the ctev_pred in sync with each other. See Note [CtEvidence invariants].

valuesetCtEvLoc :: CtEvidence -> CtLoc -> CtEvidence

#

valuetyCoVarsOfCtEvList :: CtEvidence -> [TcTyCoVar]

#

Returns free variables of constraints as a deterministically ordered list. See Note [Deterministic FV] in GHC.Types.Var.FV.

valuetyCoVarsOfCtEv :: CtEvidence -> TcTyCoVarSet

#

Returns free variables of constraints as a non-deterministic set

valuetyCoVarsOfCtEvsList :: [CtEvidence] -> [TcTyCoVar]

#

Returns free variables of a bag of constraints as a deterministically ordered list. See Note [Deterministic FV] in GHC.Types.Var.FV.

datadata GivenCtEvidence

#

Evidence for a Given constraint

Constructors

GivenCt
- ctev_pred :: TcPredType
- ctev_evar :: EvVar
- ctev_loc :: CtLoc

Instances1Outputable

Outputable GivenCtEvidenceDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

datadata WantedCtEvidence

#

Evidence for a Wanted constraint

Constructors

WantedCt
- ctev_pred :: TcPredType
- ctev_dest :: TcEvDest
- ctev_loc :: CtLoc
- ctev_rewriters :: CoHoleSet

Instances1Outputable

Outputable WantedCtEvidenceDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

newtypenewtype CoHoleSet

#

A CoHoleSet stores a set of CoercionHoles that have been used to rewrite a constraint. See Note [Wanteds rewrite Wanteds: rewriter-sets] in GHC.Tc.Types.Constraint

Constructors

CoHoleSet (UniqSet CoercionHole)

Instances3Semigroup, Monoid, Outputable

Semigroup CoHoleSetDefined in ghc-10.0.0.20260917 · GHC.Core.TyCo.Rep
Monoid CoHoleSetDefined in ghc-10.0.0.20260917 · GHC.Core.TyCo.Rep
Outputable CoHoleSetDefined in ghc-10.0.0.20260917 · GHC.Core.TyCo.Rep

valueemptyCoHoleSet :: CoHoleSet

#

valueisEmptyCoHoleSet :: CoHoleSet -> Bool

#

valueelemCoHoleSet :: CoercionHole -> CoHoleSet -> Bool

#

valueaddRewriter :: CoHoleSet -> CoercionHole -> CoHoleSet

#

valueunitCoHoleSet :: CoercionHole -> CoHoleSet

#

valueunionCoHoleSet :: CoHoleSet -> CoHoleSet -> CoHoleSet

#

valuedelCoHoleSet :: CoHoleSet -> CoercionHole -> CoHoleSet

#

datadata CoercionPlusHoles

#

Constructors

CPH
- cph_co :: Coercion
- cph_holes :: CoHoleSet

Instances1Outputable

Outputable CoercionPlusHolesDefined in ghc-10.0.0.20260917 · GHC.Core.TyCo.Rep

valuerewriterSetFromCts :: Bag Ct -> CoHoleSet

#

valuemkReflCPH :: EqRel -> Type -> CoercionPlusHoles

#

valuewrapType :: Type -> [TyVar] -> [PredType] -> Type

#

datadata CtFlavour

#

Given Wanted

Instances2Eq, Outputable

Eq CtFlavourDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint
Outputable CtFlavourDefined in ghc-10.0.0.20260917 · GHC.Tc.Types.Constraint

valuectEvFlavour :: CtEvidence -> CtFlavour

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typetype CtFlavourRole = (CtFlavour, EqRel)

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Whether or not one Ct can rewrite another is determined by its flavour and its equality relation. See also Note [Flavours with roles] in GHC.Tc.Solver.InertSet