Moduleghc-lib-parser-9.14.1.20251220GHC2021

GHC.Tc.Types.Origin

Describes the provenance of types as they flow through the type-checker. The datatypes here are mainly used for error message generation.

23 types
29 values

Packageghc-lib-parser-9.14.1.20251220
Exports52
LanguageGHC2021
LicenceBSD-3-Clause
SourceOrigin.hs

UserTypeCtxt

6 declarations

datadata UserTypeCtxt

UserTypeCtxt describes the origin of the polymorphic type in the places where we need an expression to have that type

Constructors

FunSigCtxt Name ReportRedundantConstraints
InfSigCtxt Name
ExprSigCtxt ReportRedundantConstraints
KindSigCtxt
StandaloneKindSigCtxt Name
TypeAppCtxt
ConArgCtxt Name
TySynCtxt Name
PatSynCtxt Name
PatSigCtxt
ForSigCtxt Name
DefaultDeclCtxt
InstDeclCtxt Bool
SpecInstCtxt
GenSigCtxt
GhciCtxt Bool
ClassSCCtxt Name
SigmaCtxt
DataTyCtxt Name
DerivClauseCtxt
TyVarBndrKindCtxt Name
RuleBndrTypeCtxt Name
DataKindCtxt Name
TySynKindCtxt Name
TyFamResKindCtxt Name

Instances1Eq

Eq UserTypeCtxtDefined in ghc-lib-parser-9.14.1.20251220 · GHC.Tc.Types.Origin

valuepprUserTypeCtxt :: UserTypeCtxt -> SDoc

valueisSigMaybe :: UserTypeCtxt -> Maybe Name

datadata ReportRedundantConstraints

Report Redundant Constraints.

Constructors

NoRRC
Don't report redundant constraints
WantRRC SrcSpan
Report redundant constraints The SrcSpan is for the constraints E.g. f :: (Eq a, Ord b) => blah The span is for the (Eq a, Ord b) We need to record the span here because we have long since discarded the HsType in favour of a Type

Instances1Eq

Eq ReportRedundantConstraintsDefined in ghc-lib-parser-9.14.1.20251220 · GHC.Tc.Types.Origin

valuereportRedundantConstraints :: ReportRedundantConstraints -> Bool

valueredundantConstraintsSpan :: UserTypeCtxt -> SrcSpan

SkolemInfo

8 declarations

datadata SkolemInfo

SkolemInfo stores the origin of a skolem type variable, so that we can display this information to the user in case of a type error.

The Unique field allows us to report all skolem type variables bound in the same place in a single report.

Constructors

SkolemInfo Unique SkolemInfoAnon

Instances2Uniquable, Outputable

Uniquable SkolemInfoDefined in ghc-lib-parser-9.14.1.20251220 · GHC.Tc.Types.Origin
Outputable SkolemInfoDefined in ghc-lib-parser-9.14.1.20251220 · GHC.Tc.Types.Origin

datadata SkolemInfoAnon

SkolemInfoAnon stores the origin of a skolem type variable (e.g. bound by a user-written forall, the header of a data declaration, a deriving clause, ...).

This information is displayed when reporting an error message, such as

"Couldn't match k with l"

This allows us to explain where the type variable came from.

When several skolem type variables are bound at once, prefer using SkolemInfo, which stores a Unique which allows these type variables to be reported

Constructors

SigSkol UserTypeCtxt TcType [(Name, TcTyVar)]
SigTypeSkol UserTypeCtxt
ForAllSkol TyVarBndrs
DerivSkol Type
InstSkol ClsInstOrQC PatersonSize
MethSkol Name Bool
FamInstSkol
PatSkol ConLike HsMatchContextRn
IPSkol [HsIPName]
RuleSkol RuleName
SpecESkol Name
InferSkol [(Name, TcType)]
BracketSkol
UnifyForAllSkol TcType
TyConSkol (TyConFlavour TyCon) Name
DataConSkol Name
ReifySkol
RuntimeUnkSkol
ArrowReboundIfSkol
UnkSkol CallStack

Instances1Outputable

Outputable SkolemInfoAnonDefined in ghc-lib-parser-9.14.1.20251220 · GHC.Tc.Types.Origin

valuemkSkolemInfo :: MonadIO m => SkolemInfoAnon -> m SkolemInfo

Wrap up the origin of a skolem type variable with a new Unique, so that we can common up skolem type variables whose SkolemInfo shares a certain Unique.

valuegetSkolemInfo :: SkolemInfo -> SkolemInfoAnon

valuepprSigSkolInfo :: UserTypeCtxt -> TcType -> SDoc

valuepprSkolInfo :: SkolemInfoAnon -> SDoc

valueunkSkol :: HasDebugCallStack => SkolemInfo

Use this when you can't specify a helpful origin for some skolem type variable.

We're hoping to be able to get rid of this entirely, but for the moment it's still needed.

valueunkSkolAnon :: HasDebugCallStack => SkolemInfoAnon

CtOrigin

19 declarations

datadata CtOrigin

Constructors

GivenOrigin SkolemInfoAnon
A given constraint from a user-written type signature. The SkolemInfo inside gives more information.
GivenSCOrigin SkolemInfoAnon ScDepth Bool
GivenSCOrigin is used for a Given constraint obtained by superclass selection from the context of an instance declaration. E.g. instance (Foo a, Bar a) => C [a] where ... When typechecking the instance decl itself, including producing evidence for the superclasses of C, the superclasses of (Foo a) and (Bar a) will have GivenSCOrigin origin.
OccurrenceOf Name
Occurrence of an overloaded identifier
OccurrenceOfRecSel RdrName
Occurrence of a record selector
AppOrigin
An application of some kind
SpecPragOrigin UserTypeCtxt
Specialisation pragma for function or instance
TypeEqOrigin
- uo_actual :: TcType
- uo_expected :: TcType
- uo_thing :: Maybe TypedThing
  The thing that has type "actual"
- uo_visible :: Bool
  Is at least one of the three elements above visible? (Errors from the polymorphic subsumption check are considered visible.) Only used for prioritizing error messages.
KindEqOrigin TcType TcType CtOrigin (Maybe TypeOrKind)
IPOccOrigin HsIPName
OverLabelOrigin FastString
LiteralOrigin (HsOverLit GhcRn)
NegateOrigin
ArithSeqOrigin (ArithSeqInfo GhcRn)
AssocFamPatOrigin
SectionOrigin
GetFieldOrigin FastString
TupleOrigin
ExprSigOrigin
PatSigOrigin
PatOrigin
ProvCtxtOrigin (PatSynBind GhcRn GhcRn)
RecordUpdOrigin
ViewPatOrigin
ScOrigin ClsInstOrQC NakedScFlag
ScOrigin is used only for the Wanted constraints for the superclasses of an instance declaration.
DerivOrigin StandaloneDeriv
DerivOriginDC DataCon Int StandaloneDeriv
DerivOriginCoerce Id Type Type StandaloneDeriv
DefaultOrigin
DoOrigin
DoPatOrigin (LPat GhcRn)
MCompOrigin
MCompPatOrigin (LPat GhcRn)
ProcOrigin
ArrowCmdOrigin
AnnOrigin
FunDepOrigin1 PredType CtOrigin RealSrcSpan PredType CtOrigin RealSrcSpan
FunDepOrigin2 PredType CtOrigin PredType SrcSpan
InjTFOrigin1 PredType CtOrigin RealSrcSpan PredType CtOrigin RealSrcSpan
ExprHoleOrigin (Maybe RdrName)
TypeHoleOrigin OccName
PatCheckOrigin
ListOrigin
IfThenElseOrigin
BracketOrigin
StaticOrigin
ImpedanceMatching Id
Shouldn'tHappenOrigin String
InstProvidedOrigin Module ClsInst
Testing whether the constraint associated with an instance declaration in a signature file is satisfied upon instantiation.
Test cases: backpackshould_failbkpfail{11,43}.bkp
NonLinearPatternOrigin NonLinearPatternReason (LPat GhcRn)
OmittedFieldOrigin (Maybe FieldLabel)
UsageEnvironmentOf Name
CycleBreakerOrigin CtOrigin
See Detail (7) of Note [Type equality cycles] in GHC.Tc.Solver.Equality
FRROrigin FixedRuntimeRepOrigin
WantedSuperclassOrigin PredType CtOrigin
InstanceSigOrigin Name Type Type
AmbiguityCheckOrigin UserTypeCtxt
ImplicitLiftOrigin HsImplicitLiftSplice

Instances1Outputable

Outputable CtOriginDefined in ghc-lib-parser-9.14.1.20251220 · GHC.Tc.Types.Origin

valueexprCtOrigin :: HsExpr GhcRn -> CtOrigin

valuelexprCtOrigin :: LHsExpr GhcRn -> CtOrigin

Extract a suitable CtOrigin from a HsExpr

valuematchesCtOrigin :: MatchGroup GhcRn (LHsExpr GhcRn) -> CtOrigin

Extract a suitable CtOrigin from a MatchGroup

valuegrhssCtOrigin :: GRHSs GhcRn (LHsExpr GhcRn) -> CtOrigin

Extract a suitable CtOrigin from guarded RHSs

valueisVisibleOrigin :: CtOrigin -> Bool

valuetoInvisibleOrigin :: CtOrigin -> CtOrigin

valuepprCtOrigin :: CtOrigin -> SDoc

valuepprCtOriginBriefly :: CtOrigin -> SDoc

Print CtOrigin briefly, with a one-liner

valueisGivenOrigin :: CtOrigin -> Bool

valueisWantedWantedFunDepOrigin :: CtOrigin -> Bool

valueisWantedSuperclassOrigin :: CtOrigin -> Bool

Did a constraint arise from expanding a Wanted constraint to look at superclasses?

datadata ClsInstOrQC

Constructors

IsClsInst
IsQC PredType CtOrigin

datadata NakedScFlag

NakedSc NotNakedSc

Instances1Outputable

Outputable NakedScFlagDefined in ghc-lib-parser-9.14.1.20251220 · GHC.Tc.Types.Origin

datadata NonLinearPatternReason

LazyPatternReason GeneralisedPatternReason PatternSynonymReason ViewPatternReason OtherPatternReason

datadata HsImplicitLiftSplice

Information about an implicit lift, discovered by the renamer See Note [Lifecycle of an untyped splice, and PendingRnSplice]

Constructors

HsImplicitLiftSplice
- implicit_lift_bind_lvl :: Set ThLevelIndex
- implicit_lift_used_lvl :: ThLevelIndex
- implicit_lift_gre :: Maybe GlobalRdrElt
- implicit_lift_lid :: LIdOccP GhcRn

Instances1Data

Data HsImplicitLiftSpliceDefined in ghc-lib-parser-9.14.1.20251220 · GHC.Hs.Instances · orphan

typetype StandaloneDeriv = Bool

datadata TypedThing

Some thing which has a type.

This datatype is used when we want to report to the user that something has an unexpected type.

Constructors

Instances1Outputable

Outputable TypedThingDefined in ghc-lib-parser-9.14.1.20251220 · GHC.Tc.Types.Origin

datadata TyVarBndrs

Some kind of type variable binder.

Used for reporting errors, in SkolemInfo and TcSolverReportMsg.

Constructors

forall flag. OutputableBndrFlag flag 'Renamed => HsTyVarBndrsRn [HsTyVarBndr flag GhcRn]

Instances1Outputable

Outputable TyVarBndrsDefined in ghc-lib-parser-9.14.1.20251220 · GHC.Tc.Types.Origin

CallStack

1 declaration

valueisPushCallStackOrigin_maybe :: CtOrigin -> Maybe FastString

FixedRuntimeRep origin

7 declarations

datadata FixedRuntimeRepOrigin

The context for a representation-polymorphism check.

For example, when typechecking (a :: k) -> ..., we are checking the type a because it's the type of a term variable bound in a lambda, so we use FRRBinder.

Constructors

FixedRuntimeRepOrigin
- frr_type :: Type
  What type are we checking? For example, a[tau] in a[tau] :: TYPE rr[tau].
- frr_context :: FixedRuntimeRepContext
  What context requires a fixed runtime representation?

Instances1Outputable

Outputable FixedRuntimeRepOriginDefined in ghc-lib-parser-9.14.1.20251220 · GHC.Tc.Types.Origin

datadata FixedRuntimeRepContext

The context in which a representation-polymorphism check was performed.

Does not include the type on which the check was performed; see FixedRuntimeRepOrigin for that.

Constructors

FRRRecordCon !RdrName !(HsExpr GhcTc)
Record fields in record construction must have a fixed runtime representation.
FRRRecordUpdate !Name !(HsExpr GhcRn)
Record fields in record updates must have a fixed runtime representation.
Test case: RepPolyRecordUpdate.
FRRBinder !Name
Variable binders must have a fixed runtime representation.
Test cases: LevPolyLet, RepPolyPatBind.
FRRRepPolyId !Name !RepPolyId !(Position 'Neg)
Types appearing in negative position in the type of a representation-polymorphic Id must have a fixed runtime representation.
This includes:
- arguments,
Test cases: RepPolyMagic, RepPolyRightSection, RepPolyWrappedVar, T14561b, T17817.
- continuation result types, such as in catch#, keepAlive# and control0#.
Test case: T21906.
FRRRepPolyUnliftedNewtype !DataCon
A partial application of the constructor of a representation-polymorphic unlifted newtype in which the argument type does not have a fixed runtime representation.
Test cases: UnliftedNewtypesLevityBinder, UnliftedNewtypesCoerceFail.
FRRPatBind
Pattern binds must have a fixed runtime representation.
Test case: RepPolyInferPatBind.
FRRPatSynArg
Pattern synonym arguments must have a fixed runtime representation.
Test case: RepPolyInferPatSyn.
FRRCase
The type of the scrutinee in a case statement must have a fixed runtime representation.
Test cases: RepPolyCase{1,2}.
FRRDataConPatArg !DataCon !Int
An instantiation of a newtype/data constructor pattern in which an argument type does not have a fixed runtime representation.
Test case: T20363.
FRRUnboxedTuple !Int
The RuntimeRep arguments to unboxed tuples must be concrete RuntimeReps.
Test case: RepPolyTuple.
FRRUnboxedTupleSection !Int
Tuple sections must have a fixed runtime representation.
Test case: RepPolyTupleSection.
FRRUnboxedSum !(Maybe Int)
The RuntimeRep arguments to unboxed sums must be concrete RuntimeReps.
Test cases: RepPolySum.
FRRBodyStmt !StmtOrigin !Int
The body of a do expression or a monad comprehension must have a fixed runtime representation.
Test cases: RepPolyDoBody{1,2}, RepPolyMcBody.
FRRBodyStmtGuard
Arguments to a guard in a monad comprehension must have a fixed runtime representation.
Test case: RepPolyMcGuard.
FRRBindStmt !StmtOrigin
Arguments to (>>=) arising from a do expression or a monad comprehension must have a fixed runtime representation.
Test cases: RepPolyDoBind, RepPolyMcBind.
FRRBindStmtGuard
A value bound by a pattern guard must have a fixed runtime representation.
Test cases: none.
FRRArrow !FRRArrowContext
A representation-polymorphism check arising from arrow notation.
See FRRArrowContext for more details.
FRRExpectedFunTy !ExpectedFunTyOrigin !Int
A representation-polymorphism check arising from a call to matchExpectedFunTys or matchActualFunTy.
See ExpectedFunTyOrigin for more details.
forall p. FRRDeepSubsumption
A representation-polymorphism check arising from eta-expansion performed as part of deep subsumption.
- frrDSExpected :: Bool
- frrDSPosition :: Position p

Instances1Outputable

Outputable FixedRuntimeRepContextDefined in ghc-lib-parser-9.14.1.20251220 · GHC.Tc.Types.Origin

valuepprFixedRuntimeRepContext :: FixedRuntimeRepContext -> SDoc

Print the context for a FixedRuntimeRep representation-polymorphism check.

Note that this function does not include the specific RuntimeRep which is not fixed. That information is stored in FixedRuntimeRepOrigin and is reported separately.

datadata StmtOrigin

Are we in a do expression or a monad comprehension?

This datatype is only used to report this context to the user in error messages.

MonadComprehension DoNotation

Instances1Outputable

Outputable StmtOriginDefined in ghc-lib-parser-9.14.1.20251220 · GHC.Tc.Types.Origin

datadata ArgPos

The position of an argument (to be reported in an error message).

Constructors

ArgPosInvis
Invisible argument: don't report its position to the user.
ArgPosVis !Int
Visible argument in i-th position.

valuemkFRRUnboxedTuple :: Int -> FixedRuntimeRepContext

A synonym for FRRUnboxedTuple exposed in the hs-boot file for GHC.Tc.Types.Origin.

valuemkFRRUnboxedSum :: Maybe Int -> FixedRuntimeRepContext

A synonym for FRRUnboxedSum exposed in the hs-boot file for GHC.Tc.Types.Origin.

FixedRuntimeRep origin for rep-poly Ids

datadata RepPolyId

The description of a representation-polymorphic Id.

Constructors

RepPolyPrimOp
A representation-polymorphic PrimOp.
RepPolyTuple
An unboxed tuple constructor.
RepPolySum
An unboxed sum constructor.
RepPolyFunction
An unspecified representation-polymorphic function, e.g. a pseudo-op such as coerce.

datadata Polarity

Are we in a positive (covariant) or negative (contravariant) position?

See Note [Positional information in representation-polymorphism errors].

Pos Neg

datadata Position (p :: Polarity) where

A position in which a type variable appears in a type; in particular, whether it appears in a positive or a negative position.

See Note [Positional information in representation-polymorphism errors].

Constructors

Argument :: Position p -> Position p
In the argument of a function arrow
Result :: Position p -> Position p
In the result of a function arrow
Top :: Position 'Pos
At the top level of a type

Instances2Show, Outputable

Show (Position p)Defined in ghc-lib-parser-9.14.1.20251220 · GHC.Tc.Types.Origin
Outputable (Position p)Defined in ghc-lib-parser-9.14.1.20251220 · GHC.Tc.Types.Origin

valuemkArgPos :: Int -> Position p -> Position (FlipPolarity p)

mkArgPos i p makes the Position p relative to the ith argument.

Example: ppr (mkArgPos 3 (Result Top)) == "in the result of the 3rd argument".

Arrow command FixedRuntimeRep origin

datadata FRRArrowContext

While typechecking arrow notation, in which context did a representation polymorphism check arise?

See FixedRuntimeRepContext for more general origins of representation polymorphism checks.

Constructors

ArrowCmdResTy !(HsCmd GhcRn)
The result of an arrow command does not have a fixed runtime representation.
Test case: RepPolyArrowCmd.
ArrowCmdApp !(HsCmd GhcRn) !(HsExpr GhcRn)
The argument to an arrow in an arrow command application does not have a fixed runtime representation.
Test cases: none.
ArrowCmdArrApp !(HsExpr GhcRn) !(HsExpr GhcRn) !HsArrAppType
A function in an arrow application does not have a fixed runtime representation.
Test cases: none.
ArrowCmdCase
The scrutinee type in an arrow command case statement does not have a fixed runtime representation.
Test cases: none.
ArrowFun !(HsExpr GhcRn)
The overall type of an arrow proc expression does not have a fixed runtime representation.
Test case: RepPolyArrowFun.

Instances1Outputable

Outputable FRRArrowContextDefined in ghc-lib-parser-9.14.1.20251220 · GHC.Tc.Types.Origin

valuepprFRRArrowContext :: FRRArrowContext -> SDoc

ExpectedFunTy FixedRuntimeRepOrigin

datadata ExpectedFunTyOrigin

In what context are we calling matchExpectedFunTys or matchActualFunTy?

Used for two things:

Reporting error messages which explain that a function has been given an unexpected number of arguments. Uses pprExpectedFunTyHerald. See Note [Herald for matchExpectedFunTys] in GHC.Tc.Utils.Unify.
Reporting representation-polymorphism errors when a function argument doesn't have a fixed RuntimeRep as per Note [Fixed RuntimeRep] in GHC.Tc.Utils.Concrete. Uses pprExpectedFunTyOrigin. See FixedRuntimeRepContext for the situations in which representation-polymorphism checks are performed.

Constructors

forall p. OutputableBndrId p => ExpectedFunTySyntaxOp !CtOrigin !(HsExpr (GhcPass p))
A rebindable syntax operator is expected to have a function type.
Test cases for representation-polymorphism checks: RepPolyDoBind, RepPolyDoBody{1,2}, RepPolyMc{Bind,Body,Guard}, RepPolyNPlusK
ExpectedFunTyViewPat !(HsExpr GhcRn)
A view pattern must have a function type.
Test cases for representation-polymorphism checks: RepPolyBinder
forall p. Outputable (HsExpr (GhcPass p)) => ExpectedFunTyArg !TypedThing !(HsExpr (GhcPass p))
Need to be able to extract an argument type from a function type.
Test cases for representation-polymorphism checks: RepPolyApp
ExpectedFunTyMatches !TypedThing !(MatchGroup GhcRn (LHsExpr GhcRn))
Ensure that a function defined by equations indeed has a function type with the appropriate number of arguments.
Test cases for representation-polymorphism checks: RepPolyBinder, RepPolyRecordPattern, RepPolyWildcardPattern
ExpectedFunTyLam HsLamVariant !(HsExpr GhcRn)
Ensure that a lambda abstraction has a function type.
Test cases for representation-polymorphism checks: RepPolyLambda, RepPolyMatch

valuepprExpectedFunTyOrigin

:: ExpectedFunTyOrigin
-> Int
argument position (starting at 1)
-> SDoc

valuepprExpectedFunTyHerald :: ExpectedFunTyOrigin -> SDoc

InstanceWhat

2 declarations

datadata InstanceWhat

Constructors

BuiltinEqInstance
BuiltinTypeableInstance TyCon
BuiltinInstance
LocalInstance
TopLevInstance
- iw_dfun_id :: DFunId
- iw_safe_over :: SafeOverlapping
- iw_warn :: Maybe (WarningTxt GhcRn)

Instances1Outputable

Outputable InstanceWhatDefined in ghc-lib-parser-9.14.1.20251220 · GHC.Tc.Types.Origin

typetype SafeOverlapping = Bool

Indicates if Instance met the Safe Haskell overlapping instances safety check.

See Note [Safe Haskell Overlapping Instances] in GHC.Tc.Solver See Note [Safe Haskell Overlapping Instances Implementation] in GHC.Tc.Solver