Safe Haskell	Safe-Inferred
Language	Haskell2010

GHC.Tc.Types.Constraint

Description

This module defines types and simple operations over constraints, as used in the type-checker and constraint solver.

Synopsis

data QCInst = QCI {
- qci_ev :: CtEvidence
- qci_tvs :: [TcTyVar]
- qci_pred :: TcPredType
- qci_pend_sc :: Bool
}
isPendingScInst :: QCInst -> Maybe QCInst
type Xi = TcType
data Ct
- = CDictCan {
  - cc_ev :: CtEvidence
  - cc_class :: Class
  - cc_tyargs :: [Xi]
  - cc_pend_sc :: Bool
  }
- | CIrredCan {
  - cc_ev :: CtEvidence
  - cc_status :: CtIrredStatus
  }
- | CEqCan {
  - cc_ev :: CtEvidence
  - cc_lhs :: CanEqLHS
  - cc_rhs :: Xi
  - cc_eq_rel :: EqRel
  }
- | CNonCanonical {
  - cc_ev :: CtEvidence
  }
- | CQuantCan QCInst
type Cts = Bag Ct
data CtIrredStatus
- = InsolubleCIS
- | BlockedCIS HoleSet
- | OtherCIS
type HoleSet = UniqSet CoercionHole
emptyCts :: Cts
andCts :: Cts -> Cts -> Cts
andManyCts :: [Cts] -> Cts
pprCts :: Cts -> SDoc
singleCt :: Ct -> Cts
listToCts :: [Ct] -> Cts
ctsElts :: Cts -> [Ct]
consCts :: Ct -> Cts -> Cts
snocCts :: Cts -> Ct -> Cts
extendCtsList :: Cts -> [Ct] -> Cts
isEmptyCts :: Cts -> Bool
isPendingScDict :: Ct -> Maybe Ct
superClassesMightHelp :: WantedConstraints -> Bool
getPendingWantedScs :: Cts -> ([Ct], Cts)
isWantedCt :: Ct -> Bool
isDerivedCt :: Ct -> Bool
isGivenCt :: Ct -> Bool
isUserTypeErrorCt :: Ct -> Bool
getUserTypeErrorMsg :: Ct -> Maybe Type
ctEvidence :: Ct -> CtEvidence
ctLoc :: Ct -> CtLoc
setCtLoc :: Ct -> CtLoc -> Ct
ctPred :: Ct -> PredType
ctFlavour :: Ct -> CtFlavour
ctEqRel :: Ct -> EqRel
ctOrigin :: Ct -> CtOrigin
ctEvId :: Ct -> EvVar
mkTcEqPredLikeEv :: CtEvidence -> TcType -> TcType -> TcType
mkNonCanonical :: CtEvidence -> Ct
mkNonCanonicalCt :: Ct -> Ct
mkGivens :: CtLoc -> [EvId] -> [Ct]
mkIrredCt :: CtIrredStatus -> CtEvidence -> Ct
ctEvPred :: CtEvidence -> TcPredType
ctEvLoc :: CtEvidence -> CtLoc
ctEvOrigin :: CtEvidence -> CtOrigin
ctEvEqRel :: CtEvidence -> EqRel
ctEvExpr :: CtEvidence -> EvExpr
ctEvTerm :: CtEvidence -> EvTerm
ctEvCoercion :: HasDebugCallStack => CtEvidence -> TcCoercion
ctEvEvId :: CtEvidence -> EvVar
tyCoVarsOfCt :: Ct -> TcTyCoVarSet
tyCoVarsOfCts :: Cts -> TcTyCoVarSet
tyCoVarsOfCtList :: Ct -> [TcTyCoVar]
tyCoVarsOfCtsList :: Cts -> [TcTyCoVar]
data CanEqLHS
- = TyVarLHS TcTyVar
- | TyFamLHS TyCon [Xi]
canEqLHS_maybe :: Xi -> Maybe CanEqLHS
canEqLHSKind :: CanEqLHS -> TcKind
canEqLHSType :: CanEqLHS -> TcType
eqCanEqLHS :: CanEqLHS -> CanEqLHS -> Bool
data Hole = Hole {
- hole_sort :: HoleSort
- hole_occ :: OccName
- hole_ty :: TcType
- hole_loc :: CtLoc
}
data HoleSort
- = ExprHole HoleExprRef
- | TypeHole
- | ConstraintHole
isOutOfScopeHole :: Hole -> Bool
data WantedConstraints = WC {
- wc_simple :: Cts
- wc_impl :: Bag Implication
- wc_holes :: Bag Hole
}
insolubleWC :: WantedConstraints -> Bool
emptyWC :: WantedConstraints
isEmptyWC :: WantedConstraints -> Bool
isSolvedWC :: WantedConstraints -> Bool
andWC :: WantedConstraints -> WantedConstraints -> WantedConstraints
unionsWC :: [WantedConstraints] -> WantedConstraints
mkSimpleWC :: [CtEvidence] -> WantedConstraints
mkImplicWC :: Bag Implication -> WantedConstraints
addInsols :: WantedConstraints -> Bag Ct -> WantedConstraints
dropMisleading :: WantedConstraints -> WantedConstraints
addSimples :: WantedConstraints -> Bag Ct -> WantedConstraints
addImplics :: WantedConstraints -> Bag Implication -> WantedConstraints
addHoles :: WantedConstraints -> Bag Hole -> WantedConstraints
tyCoVarsOfWC :: WantedConstraints -> TyCoVarSet
dropDerivedWC :: WantedConstraints -> WantedConstraints
dropDerivedSimples :: Cts -> Cts
tyCoVarsOfWCList :: WantedConstraints -> [TyCoVar]
insolubleCt :: Ct -> Bool
insolubleEqCt :: Ct -> Bool
isDroppableCt :: Ct -> Bool
insolubleImplic :: Implication -> Bool
arisesFromGivens :: Ct -> Bool
data Implication = Implic {
- ic_tclvl :: TcLevel
- ic_skols :: [TcTyVar]
- ic_info :: SkolemInfo
- ic_given :: [EvVar]
- ic_given_eqs :: HasGivenEqs
- ic_warn_inaccessible :: Bool
- ic_env :: TcLclEnv
- ic_wanted :: WantedConstraints
- ic_binds :: EvBindsVar
- ic_need_inner :: VarSet
- ic_need_outer :: VarSet
- ic_status :: ImplicStatus
}
implicationPrototype :: Implication
checkTelescopeSkol :: SkolemInfo -> Bool
data ImplicStatus
- = IC_Solved {
  - ics_dead :: [EvVar]
  }
- | IC_Insoluble
- | IC_BadTelescope
- | IC_Unsolved
isInsolubleStatus :: ImplicStatus -> Bool
isSolvedStatus :: ImplicStatus -> Bool
data HasGivenEqs
- = NoGivenEqs
- | LocalGivenEqs
- | MaybeGivenEqs
data SubGoalDepth
initialSubGoalDepth :: SubGoalDepth
maxSubGoalDepth :: SubGoalDepth -> SubGoalDepth -> SubGoalDepth
bumpSubGoalDepth :: SubGoalDepth -> SubGoalDepth
subGoalDepthExceeded :: DynFlags -> SubGoalDepth -> Bool
data CtLoc = CtLoc {
- ctl_origin :: CtOrigin
- ctl_env :: TcLclEnv
- ctl_t_or_k :: Maybe TypeOrKind
- ctl_depth :: !SubGoalDepth
}
ctLocSpan :: CtLoc -> RealSrcSpan
ctLocEnv :: CtLoc -> TcLclEnv
ctLocLevel :: CtLoc -> TcLevel
ctLocOrigin :: CtLoc -> CtOrigin
ctLocTypeOrKind_maybe :: CtLoc -> Maybe TypeOrKind
ctLocDepth :: CtLoc -> SubGoalDepth
bumpCtLocDepth :: CtLoc -> CtLoc
isGivenLoc :: CtLoc -> Bool
setCtLocOrigin :: CtLoc -> CtOrigin -> CtLoc
updateCtLocOrigin :: CtLoc -> (CtOrigin -> CtOrigin) -> CtLoc
setCtLocEnv :: CtLoc -> TcLclEnv -> CtLoc
setCtLocSpan :: CtLoc -> RealSrcSpan -> CtLoc
pprCtLoc :: CtLoc -> SDoc
data CtEvidence
- = CtGiven {
  - ctev_pred :: TcPredType
  - ctev_evar :: EvVar
  - ctev_loc :: CtLoc
  }
- | CtWanted {
  - ctev_pred :: TcPredType
  - ctev_dest :: TcEvDest
  - ctev_nosh :: ShadowInfo
  - ctev_loc :: CtLoc
  }
- | CtDerived {
  - ctev_pred :: TcPredType
  - ctev_loc :: CtLoc
  }
data TcEvDest
- = EvVarDest EvVar
- | HoleDest CoercionHole
mkKindLoc :: TcType -> TcType -> CtLoc -> CtLoc
toKindLoc :: CtLoc -> CtLoc
mkGivenLoc :: TcLevel -> SkolemInfo -> TcLclEnv -> CtLoc
isWanted :: CtEvidence -> Bool
isGiven :: CtEvidence -> Bool
isDerived :: CtEvidence -> Bool
ctEvRole :: CtEvidence -> Role
wrapType :: Type -> [TyVar] -> [PredType] -> Type
data CtFlavour
- = Given
- | Wanted ShadowInfo
- | Derived
data ShadowInfo
- = WDeriv
- | WOnly
ctEvFlavour :: CtEvidence -> CtFlavour
type CtFlavourRole = (CtFlavour, EqRel)
ctEvFlavourRole :: CtEvidence -> CtFlavourRole
ctFlavourRole :: Ct -> CtFlavourRole
eqCanRewrite :: EqRel -> EqRel -> Bool
eqCanRewriteFR :: CtFlavourRole -> CtFlavourRole -> Bool
eqMayRewriteFR :: CtFlavourRole -> CtFlavourRole -> Bool
eqCanDischargeFR :: CtFlavourRole -> CtFlavourRole -> Bool
pprEvVarTheta :: [EvVar] -> SDoc
pprEvVars :: [EvVar] -> SDoc
pprEvVarWithType :: EvVar -> SDoc

Documentation

data QCInst Source #

Constructors

QCI
Fields qci_ev :: CtEvidence qci_tvs :: [TcTyVar] qci_pred :: TcPredType qci_pend_sc :: Bool

Instances

Instances details

Outputable QCInst #
Instance details Defined in GHC.Tc.Types.Constraint Methods ppr :: QCInst -> SDoc Source #

isPendingScInst :: QCInst -> Maybe QCInst Source #

type Xi = TcType Source #

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.)

data Ct Source #

Constructors

CDictCan
Fields cc_ev :: CtEvidence cc_class :: Class cc_tyargs :: [Xi] cc_pend_sc :: Bool
CIrredCan
Fields cc_ev :: CtEvidence cc_status :: CtIrredStatus
CEqCan
Fields cc_ev :: CtEvidence cc_lhs :: CanEqLHS cc_rhs :: Xi cc_eq_rel :: EqRel
CNonCanonical
Fields cc_ev :: CtEvidence
CQuantCan QCInst

Instances

Instances details

Outputable Ct #
Instance details Defined in GHC.Tc.Types.Constraint Methods ppr :: Ct -> SDoc Source #

type Cts = Bag Ct Source #

data CtIrredStatus Source #

Used to indicate extra information about why a CIrredCan is irreducible

Constructors

InsolubleCIS
BlockedCIS HoleSet
OtherCIS

Instances

Instances details

Outputable CtIrredStatus #
Instance details Defined in GHC.Tc.Types.Constraint Methods ppr :: CtIrredStatus -> SDoc Source #

type HoleSet = UniqSet CoercionHole Source #

A set of CoercionHoles

emptyCts :: Cts Source #

andCts :: Cts -> Cts -> Cts Source #

andManyCts :: [Cts] -> Cts Source #

pprCts :: Cts -> SDoc Source #

singleCt :: Ct -> Cts Source #

listToCts :: [Ct] -> Cts Source #

ctsElts :: Cts -> [Ct] Source #

consCts :: Ct -> Cts -> Cts Source #

snocCts :: Cts -> Ct -> Cts Source #

extendCtsList :: Cts -> [Ct] -> Cts Source #

isEmptyCts :: Cts -> Bool Source #

isPendingScDict :: Ct -> Maybe Ct Source #

superClassesMightHelp :: WantedConstraints -> Bool Source #

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]

getPendingWantedScs :: Cts -> ([Ct], Cts) Source #

isWantedCt :: Ct -> Bool Source #

isDerivedCt :: Ct -> Bool Source #

isGivenCt :: Ct -> Bool Source #

isUserTypeErrorCt :: Ct -> Bool Source #

getUserTypeErrorMsg :: Ct -> Maybe Type Source #

A constraint is considered to be a custom type error, if it contains custom type errors anywhere in it. See Note [Custom type errors in constraints]

ctEvidence :: Ct -> CtEvidence Source #

ctLoc :: Ct -> CtLoc Source #

setCtLoc :: Ct -> CtLoc -> Ct Source #

ctPred :: Ct -> PredType Source #

ctFlavour :: Ct -> CtFlavour Source #

Get the flavour of the given Ct

ctEqRel :: Ct -> EqRel Source #

Get the equality relation for the given Ct

ctOrigin :: Ct -> CtOrigin Source #

ctEvId :: Ct -> EvVar Source #

mkTcEqPredLikeEv :: CtEvidence -> TcType -> TcType -> TcType Source #

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

mkNonCanonical :: CtEvidence -> Ct Source #

mkNonCanonicalCt :: Ct -> Ct Source #

mkGivens :: CtLoc -> [EvId] -> [Ct] Source #

mkIrredCt :: CtIrredStatus -> CtEvidence -> Ct Source #

ctEvPred :: CtEvidence -> TcPredType Source #

ctEvLoc :: CtEvidence -> CtLoc Source #

ctEvOrigin :: CtEvidence -> CtOrigin Source #

ctEvEqRel :: CtEvidence -> EqRel Source #

Get the equality relation relevant for a CtEvidence

ctEvExpr :: CtEvidence -> EvExpr Source #

ctEvTerm :: CtEvidence -> EvTerm Source #

ctEvCoercion :: HasDebugCallStack => CtEvidence -> TcCoercion Source #

ctEvEvId :: CtEvidence -> EvVar Source #

tyCoVarsOfCt :: Ct -> TcTyCoVarSet Source #

Returns free variables of constraints as a non-deterministic set

tyCoVarsOfCts :: Cts -> TcTyCoVarSet Source #

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

tyCoVarsOfCtList :: Ct -> [TcTyCoVar] Source #

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

tyCoVarsOfCtsList :: Cts -> [TcTyCoVar] Source #

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

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 TcTyVar
TyFamLHS
Fields TyCon of the family [Xi] exactly saturating the family

Instances

Instances details

Outputable CanEqLHS #
Instance details Defined in GHC.Tc.Types.Constraint Methods ppr :: CanEqLHS -> SDoc Source #

canEqLHS_maybe :: Xi -> 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.

canEqLHSKind :: CanEqLHS -> TcKind Source #

Retrieve the kind of a CanEqLHS

canEqLHSType :: CanEqLHS -> TcType Source #

Convert a CanEqLHS back into a Expr

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

Are two CanEqLHSs equal?

data Hole Source #

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].

Constructors

Hole
Fields hole_sort :: HoleSort What flavour of hole is this? hole_occ :: OccName 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

Instances

Instances details

Outputable Hole #
Instance details Defined in GHC.Tc.Types.Constraint Methods ppr :: Hole -> SDoc Source #

data HoleSort Source #

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.

Instances

Instances details

Outputable HoleSort #
Instance details Defined in GHC.Tc.Types.Constraint Methods ppr :: HoleSort -> SDoc Source #

isOutOfScopeHole :: Hole -> Bool Source #

Does this hole represent an "out of scope" error? See Note [Insoluble holes]

data WantedConstraints Source #

Constructors

WC
Fields wc_simple :: Cts wc_impl :: Bag Implication wc_holes :: Bag Hole

Instances

Instances details

Outputable WantedConstraints #
Instance details Defined in GHC.Tc.Types.Constraint Methods ppr :: WantedConstraints -> SDoc Source #

insolubleWC :: WantedConstraints -> Bool Source #

emptyWC :: WantedConstraints Source #

isEmptyWC :: WantedConstraints -> Bool Source #

isSolvedWC :: WantedConstraints -> Bool Source #

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

andWC :: WantedConstraints -> WantedConstraints -> WantedConstraints Source #

unionsWC :: [WantedConstraints] -> WantedConstraints Source #

mkSimpleWC :: [CtEvidence] -> WantedConstraints Source #

mkImplicWC :: Bag Implication -> WantedConstraints Source #

addInsols :: WantedConstraints -> Bag Ct -> WantedConstraints Source #

dropMisleading :: WantedConstraints -> WantedConstraints Source #

addSimples :: WantedConstraints -> Bag Ct -> WantedConstraints Source #

addImplics :: WantedConstraints -> Bag Implication -> WantedConstraints Source #

addHoles :: WantedConstraints -> Bag Hole -> WantedConstraints Source #

tyCoVarsOfWC :: WantedConstraints -> TyCoVarSet Source #

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

dropDerivedWC :: WantedConstraints -> WantedConstraints Source #

dropDerivedSimples :: Cts -> Cts Source #

tyCoVarsOfWCList :: WantedConstraints -> [TyCoVar] Source #

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

insolubleCt :: Ct -> Bool Source #

insolubleEqCt :: Ct -> Bool Source #

isDroppableCt :: Ct -> Bool Source #

insolubleImplic :: Implication -> Bool Source #

arisesFromGivens :: Ct -> Bool Source #

data Implication Source #

Constructors

Implic
Fields ic_tclvl :: TcLevel ic_skols :: [TcTyVar] ic_info :: SkolemInfo ic_given :: [EvVar] ic_given_eqs :: HasGivenEqs ic_warn_inaccessible :: Bool ic_env :: TcLclEnv ic_wanted :: WantedConstraints ic_binds :: EvBindsVar ic_need_inner :: VarSet ic_need_outer :: VarSet ic_status :: ImplicStatus

Instances

Instances details

Outputable Implication #
Instance details Defined in GHC.Tc.Types.Constraint Methods ppr :: Implication -> SDoc Source #

implicationPrototype :: Implication Source #

checkTelescopeSkol :: SkolemInfo -> Bool Source #

data ImplicStatus Source #

Constructors

IC_Solved
Fields ics_dead :: [EvVar]
IC_Insoluble
IC_BadTelescope
IC_Unsolved

Instances

Instances details

Outputable ImplicStatus #
Instance details Defined in GHC.Tc.Types.Constraint Methods ppr :: ImplicStatus -> SDoc Source #

isInsolubleStatus :: ImplicStatus -> Bool Source #

isSolvedStatus :: ImplicStatus -> Bool Source #

data HasGivenEqs Source #

Constructors

NoGivenEqs
LocalGivenEqs
MaybeGivenEqs

Instances

Instances details

Monoid HasGivenEqs #
Instance details Defined in GHC.Tc.Types.Constraint Methods mempty :: HasGivenEqs Source # mappend :: HasGivenEqs -> HasGivenEqs -> HasGivenEqs Source # mconcat :: [HasGivenEqs] -> HasGivenEqs Source #
Semigroup HasGivenEqs #
Instance details Defined in GHC.Tc.Types.Constraint Methods (<>) :: HasGivenEqs -> HasGivenEqs -> HasGivenEqs Source # sconcat :: NonEmpty HasGivenEqs -> HasGivenEqs Source # stimes :: Integral b => b -> HasGivenEqs -> HasGivenEqs Source #
Outputable HasGivenEqs #
Instance details Defined in GHC.Tc.Types.Constraint Methods ppr :: HasGivenEqs -> SDoc Source #
Eq HasGivenEqs #
Instance details Defined in GHC.Tc.Types.Constraint Methods (==) :: HasGivenEqs -> HasGivenEqs -> Bool # (/=) :: HasGivenEqs -> HasGivenEqs -> Bool #

data SubGoalDepth Source #

See Note [SubGoalDepth]

Instances

Instances details

Outputable SubGoalDepth #
Instance details Defined in GHC.Tc.Types.Constraint Methods ppr :: SubGoalDepth -> SDoc Source #
Eq SubGoalDepth #
Instance details Defined in GHC.Tc.Types.Constraint Methods (==) :: SubGoalDepth -> SubGoalDepth -> Bool # (/=) :: SubGoalDepth -> SubGoalDepth -> Bool #
Ord SubGoalDepth #
Instance details Defined in GHC.Tc.Types.Constraint Methods compare :: SubGoalDepth -> SubGoalDepth -> Ordering # (<) :: SubGoalDepth -> SubGoalDepth -> Bool # (<=) :: SubGoalDepth -> SubGoalDepth -> Bool # (>) :: SubGoalDepth -> SubGoalDepth -> Bool # (>=) :: SubGoalDepth -> SubGoalDepth -> Bool # max :: SubGoalDepth -> SubGoalDepth -> SubGoalDepth # min :: SubGoalDepth -> SubGoalDepth -> SubGoalDepth #

initialSubGoalDepth :: SubGoalDepth Source #

maxSubGoalDepth :: SubGoalDepth -> SubGoalDepth -> SubGoalDepth Source #

bumpSubGoalDepth :: SubGoalDepth -> SubGoalDepth Source #

subGoalDepthExceeded :: DynFlags -> SubGoalDepth -> Bool Source #

data CtLoc Source #

Constructors

CtLoc
Fields ctl_origin :: CtOrigin ctl_env :: TcLclEnv ctl_t_or_k :: Maybe TypeOrKind ctl_depth :: !SubGoalDepth

ctLocSpan :: CtLoc -> RealSrcSpan Source #

ctLocEnv :: CtLoc -> TcLclEnv Source #

ctLocLevel :: CtLoc -> TcLevel Source #

ctLocOrigin :: CtLoc -> CtOrigin Source #

ctLocTypeOrKind_maybe :: CtLoc -> Maybe TypeOrKind Source #

ctLocDepth :: CtLoc -> SubGoalDepth Source #

bumpCtLocDepth :: CtLoc -> CtLoc Source #

isGivenLoc :: CtLoc -> Bool Source #

setCtLocOrigin :: CtLoc -> CtOrigin -> CtLoc Source #

updateCtLocOrigin :: CtLoc -> (CtOrigin -> CtOrigin) -> CtLoc Source #

setCtLocEnv :: CtLoc -> TcLclEnv -> CtLoc Source #

setCtLocSpan :: CtLoc -> RealSrcSpan -> CtLoc Source #

pprCtLoc :: CtLoc -> SDoc Source #

data CtEvidence Source #

Constructors

CtGiven
Fields ctev_pred :: TcPredType ctev_evar :: EvVar ctev_loc :: CtLoc
CtWanted
Fields ctev_pred :: TcPredType ctev_dest :: TcEvDest ctev_nosh :: ShadowInfo ctev_loc :: CtLoc
CtDerived
Fields ctev_pred :: TcPredType ctev_loc :: CtLoc

Instances

Instances details

Outputable CtEvidence #
Instance details Defined in GHC.Tc.Types.Constraint Methods ppr :: CtEvidence -> SDoc Source #

data TcEvDest Source #

A place for type-checking evidence to go after it is generated. Wanted equalities are always HoleDest; other wanteds are always 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

Instances

Instances details

Outputable TcEvDest #
Instance details Defined in GHC.Tc.Types.Constraint Methods ppr :: TcEvDest -> SDoc Source #

mkKindLoc :: TcType -> TcType -> CtLoc -> CtLoc Source #

toKindLoc :: CtLoc -> CtLoc Source #

Take a CtLoc and moves it to the kind level

mkGivenLoc :: TcLevel -> SkolemInfo -> TcLclEnv -> CtLoc Source #

isWanted :: CtEvidence -> Bool Source #

isGiven :: CtEvidence -> Bool Source #

isDerived :: CtEvidence -> Bool Source #

ctEvRole :: CtEvidence -> Role Source #

Get the role relevant for a CtEvidence

wrapType :: Type -> [TyVar] -> [PredType] -> Type Source #

data CtFlavour Source #

Constructors

Given
Wanted ShadowInfo
Derived

Instances

Instances details

Outputable CtFlavour #
Instance details Defined in GHC.Tc.Types.Constraint Methods ppr :: CtFlavour -> SDoc Source #
Eq CtFlavour #
Instance details Defined in GHC.Tc.Types.Constraint Methods (==) :: CtFlavour -> CtFlavour -> Bool # (/=) :: CtFlavour -> CtFlavour -> Bool #

data ShadowInfo Source #

Constructors

WDeriv
WOnly

Instances

Instances details

Eq ShadowInfo #
Instance details Defined in GHC.Tc.Types.Constraint Methods (==) :: ShadowInfo -> ShadowInfo -> Bool # (/=) :: ShadowInfo -> ShadowInfo -> Bool #

ctEvFlavour :: CtEvidence -> CtFlavour Source #

type CtFlavourRole = (CtFlavour, EqRel) Source #

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.Monad

ctEvFlavourRole :: CtEvidence -> CtFlavourRole Source #

Extract the flavour, role, and boxity from a CtEvidence

ctFlavourRole :: Ct -> CtFlavourRole Source #

Extract the flavour and role from a Ct

eqCanRewrite :: EqRel -> EqRel -> Bool Source #

eqCanRewriteFR :: CtFlavourRole -> CtFlavourRole -> Bool Source #

eqMayRewriteFR :: CtFlavourRole -> CtFlavourRole -> Bool Source #

eqCanDischargeFR :: CtFlavourRole -> CtFlavourRole -> Bool Source #

pprEvVarTheta :: [EvVar] -> SDoc Source #

pprEvVars :: [EvVar] -> SDoc Source #

pprEvVarWithType :: EvVar -> SDoc Source #