Safe Haskell	None
Language	Haskell2010

GHC.Tc.Types.Origin

Description

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

Synopsis

data UserTypeCtxt
- = FunSigCtxt Name ReportRedundantConstraints
- | InfSigCtxt Name
- | ExprSigCtxt ReportRedundantConstraints
- | KindSigCtxt
- | StandaloneKindSigCtxt Name
- | TypeAppCtxt
- | ConArgCtxt Name
- | TySynCtxt Name
- | PatSynCtxt Name
- | PatSigCtxt
- | RuleSigCtxt FastString Name
- | ForSigCtxt Name
- | DefaultDeclCtxt
- | InstDeclCtxt Bool
- | SpecInstCtxt
- | GenSigCtxt
- | GhciCtxt Bool
- | ClassSCCtxt Name
- | SigmaCtxt
- | DataTyCtxt Name
- | DerivClauseCtxt
- | TyVarBndrKindCtxt Name
- | DataKindCtxt Name
- | TySynKindCtxt Name
- | TyFamResKindCtxt Name
pprUserTypeCtxt :: UserTypeCtxt -> SDoc
isSigMaybe :: UserTypeCtxt -> Maybe Name
data ReportRedundantConstraints
- = NoRRC
- | WantRRC SrcSpan
reportRedundantConstraints :: ReportRedundantConstraints -> Bool
redundantConstraintsSpan :: UserTypeCtxt -> SrcSpan
data SkolemInfo = SkolemInfo Unique SkolemInfoAnon
data SkolemInfoAnon
- = SigSkol UserTypeCtxt TcType [(Name, TcTyVar)]
- | SigTypeSkol UserTypeCtxt
- | ForAllSkol TyVarBndrs
- | DerivSkol Type
- | InstSkol
- | FamInstSkol
- | PatSkol ConLike (HsMatchContext GhcTc)
- | IPSkol [HsIPName]
- | RuleSkol RuleName
- | InferSkol [(Name, TcType)]
- | BracketSkol
- | UnifyForAllSkol TcType
- | TyConSkol TyConFlavour Name
- | DataConSkol Name
- | ReifySkol
- | QuantCtxtSkol
- | RuntimeUnkSkol
- | ArrowReboundIfSkol
- | UnkSkol CallStack
mkSkolemInfo :: MonadIO m => SkolemInfoAnon -> m SkolemInfo
getSkolemInfo :: SkolemInfo -> SkolemInfoAnon
pprSigSkolInfo :: UserTypeCtxt -> TcType -> SDoc
pprSkolInfo :: SkolemInfoAnon -> SDoc
unkSkol :: HasCallStack => SkolemInfo
unkSkolAnon :: HasCallStack => SkolemInfoAnon
data CtOrigin
- = GivenOrigin SkolemInfoAnon
- | InstSCOrigin ScDepth TypeSize
- | OtherSCOrigin ScDepth SkolemInfoAnon
- | OccurrenceOf Name
- | OccurrenceOfRecSel RdrName
- | AppOrigin
- | SpecPragOrigin UserTypeCtxt
- | TypeEqOrigin {
  - uo_actual :: TcType
  - uo_expected :: TcType
  - uo_thing :: Maybe TypedThing
  - uo_visible :: Bool
  }
- | KindEqOrigin TcType TcType CtOrigin (Maybe TypeOrKind)
- | IPOccOrigin HsIPName
- | OverLabelOrigin FastString
- | LiteralOrigin (HsOverLit GhcRn)
- | NegateOrigin
- | ArithSeqOrigin (ArithSeqInfo GhcRn)
- | AssocFamPatOrigin
- | SectionOrigin
- | HasFieldOrigin FastString
- | TupleOrigin
- | ExprSigOrigin
- | PatSigOrigin
- | PatOrigin
- | ProvCtxtOrigin (PatSynBind GhcRn GhcRn)
- | RecordUpdOrigin
- | ViewPatOrigin
- | ScOrigin TypeSize
- | DerivClauseOrigin
- | DerivOriginDC DataCon Int Bool
- | DerivOriginCoerce Id Type Type Bool
- | StandAloneDerivOrigin
- | DefaultOrigin
- | DoOrigin
- | DoPatOrigin (LPat GhcRn)
- | MCompOrigin
- | MCompPatOrigin (LPat GhcRn)
- | ProcOrigin
- | ArrowCmdOrigin
- | AnnOrigin
- | FunDepOrigin1 PredType CtOrigin RealSrcSpan PredType CtOrigin RealSrcSpan
- | FunDepOrigin2 PredType CtOrigin PredType SrcSpan
- | ExprHoleOrigin OccName
- | TypeHoleOrigin OccName
- | PatCheckOrigin
- | ListOrigin
- | IfThenElseOrigin
- | BracketOrigin
- | StaticOrigin
- | Shouldn'tHappenOrigin String
- | InstProvidedOrigin Module ClsInst
- | NonLinearPatternOrigin
- | UsageEnvironmentOf Name
- | CycleBreakerOrigin CtOrigin
- | FixedRuntimeRepOrigin !Type !FRROrigin
exprCtOrigin :: HsExpr GhcRn -> CtOrigin
lexprCtOrigin :: LHsExpr GhcRn -> CtOrigin
matchesCtOrigin :: MatchGroup GhcRn (LHsExpr GhcRn) -> CtOrigin
grhssCtOrigin :: GRHSs GhcRn (LHsExpr GhcRn) -> CtOrigin
isVisibleOrigin :: CtOrigin -> Bool
toInvisibleOrigin :: CtOrigin -> CtOrigin
pprCtOrigin :: CtOrigin -> SDoc
isGivenOrigin :: CtOrigin -> Bool
data TypedThing
- = HsTypeRnThing (HsType GhcRn)
- | TypeThing Type
- | HsExprRnThing (HsExpr GhcRn)
- | NameThing Name
data TyVarBndrs = forall flag.OutputableBndrFlag flag 'Renamed => HsTyVarBndrsRn [HsTyVarBndr flag GhcRn]
isPushCallStackOrigin :: CtOrigin -> Bool
callStackOriginFS :: CtOrigin -> FastString
data FRROrigin
- = FRRApp !(HsExpr GhcRn)
- | FRRRecordUpdate !RdrName !(HsExpr GhcRn)
- | FRRBinder !Name
- | FRRMatch !(HsMatchContext GhcTc) !Int
- | FRRDataConArg !DataCon !Int
- | FRRNoBindingResArg !Id !Int
- | FRRTupleArg !Int
- | FRRTupleSection !Int
- | FRRUnboxedSum
- | FRRBodyStmt !StmtOrigin !Int
- | FRRBodyStmtGuard
- | FRRBindStmt !StmtOrigin
- | FRRBindStmtGuard
- | FRRArrow !FRRArrowOrigin
- | FRRWpFun !WpFunOrigin
pprFRROrigin :: FRROrigin -> SDoc
data StmtOrigin
- = MonadComprehension
- | DoNotation
data FRRArrowOrigin
- = ArrowCmdResTy !(HsCmd GhcRn)
- | ArrowCmdApp !(HsCmd GhcRn) !(HsExpr GhcRn)
- | ArrowCmdArrApp !(HsExpr GhcRn) !(HsExpr GhcRn) !HsArrAppType
- | ArrowCmdLam !Int
- | ArrowFun !(HsExpr GhcRn)
pprFRRArrowOrigin :: FRRArrowOrigin -> SDoc
data WpFunOrigin
- = WpFunSyntaxOp !CtOrigin
- | WpFunViewPat !(HsExpr GhcRn)
- | WpFunFunTy !Type
- | WpFunFunExpTy !ExpType
pprWpFunOrigin :: WpFunOrigin -> SDoc

Documentation

data UserTypeCtxt Source #

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

Instances

Instances details

Eq UserTypeCtxt Source #
Instance details Defined in GHC.Tc.Types.Origin Methods (==) :: UserTypeCtxt -> UserTypeCtxt -> Bool # (/=) :: UserTypeCtxt -> UserTypeCtxt -> Bool #

pprUserTypeCtxt :: UserTypeCtxt -> SDoc Source #

isSigMaybe :: UserTypeCtxt -> Maybe Name Source #

data ReportRedundantConstraints Source #

Report Redundant Constraints.

Constructors

NoRRC	Don't report redundant constraints
WantRRC SrcSpan	Report redundant constraints, and here is the SrcSpan for the constraints E.g. f :: (Eq a, Ord b) => blah The span is for the (Eq a, Ord b)

Instances

Instances details

Eq ReportRedundantConstraints Source #
Instance details Defined in GHC.Tc.Types.Origin Methods (==) :: ReportRedundantConstraints -> ReportRedundantConstraints -> Bool # (/=) :: ReportRedundantConstraints -> ReportRedundantConstraints -> Bool #

reportRedundantConstraints :: ReportRedundantConstraints -> Bool Source #

redundantConstraintsSpan :: UserTypeCtxt -> SrcSpan Source #

data SkolemInfo Source #

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
Fields Unique used to common up skolem variables bound at the same location (only used in pprSkols) SkolemInfoAnon the information about the origin of the skolem type variable

Instances

Instances details

Outputable SkolemInfo Source #
Instance details Defined in GHC.Tc.Types.Origin Methods ppr :: SkolemInfo -> SDoc Source #
Uniquable SkolemInfo Source #
Instance details Defined in GHC.Tc.Types.Origin Methods getUnique :: SkolemInfo -> Unique Source #

data SkolemInfoAnon Source #

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

Instances

Instances details

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

mkSkolemInfo :: MonadIO m => SkolemInfoAnon -> m SkolemInfo Source #

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.

getSkolemInfo :: SkolemInfo -> SkolemInfoAnon Source #

pprSigSkolInfo :: UserTypeCtxt -> TcType -> SDoc Source #

pprSkolInfo :: SkolemInfoAnon -> SDoc Source #

unkSkol :: HasCallStack => SkolemInfo Source #

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.

unkSkolAnon :: HasCallStack => SkolemInfoAnon Source #

data CtOrigin Source #

Constructors

GivenOrigin SkolemInfoAnon	A given constraint from a user-written type signature. The `SkolemInfo` inside gives more information.
InstSCOrigin	`InstSCOrigin` 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 `InstSCOrigin` origin.
Fields ScDepth The number of superclass selections necessary to get this constraint; see Note [Replacement vs keeping] and Note [Use only the best local instance], both in GHC.Tc.Solver.Interact TypeSize If `(C ty1 .. tyn)` is the largest class from which we made a superclass selection in the chain, then `TypeSize = sizeTypes [ty1, .., tyn]` See Note [Solving superclass constraints] in GHC.Tc.TyCl.Instance
OtherSCOrigin	`OtherSCOrigin` is used for a Given constraint obtained by superclass selection from a constraint other than the context of an instance declaration. (For the latter we use `InstSCOrigin`.) E.g. f :: Foo a => blah f = e When typechecking body of `f`, the superclasses of the Given (Foo a) will have `OtherSCOrigin`. Needed for Note [Replacement vs keeping] and Note [Use only the best local instance], both in GHC.Tc.Solver.Interact.
Fields ScDepth The number of superclass selections necessary to get this constraint SkolemInfoAnon Where the sub-class constraint arose from (used only for printing)
OccurrenceOf Name
OccurrenceOfRecSel RdrName
AppOrigin
SpecPragOrigin UserTypeCtxt
TypeEqOrigin
Fields 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
HasFieldOrigin FastString
TupleOrigin
ExprSigOrigin
PatSigOrigin
PatOrigin
ProvCtxtOrigin (PatSynBind GhcRn GhcRn)
RecordUpdOrigin
ViewPatOrigin
ScOrigin TypeSize	`ScOrigin` is used only for the Wanted constraints for the superclasses of an instance declaration. If the instance head is `C ty1 .. tyn` then `TypeSize = sizeTypes [ty1, .., tyn]` See Note [Solving superclass constraints] in GHC.Tc.TyCl.Instance
DerivClauseOrigin
DerivOriginDC DataCon Int Bool
DerivOriginCoerce Id Type Type Bool
StandAloneDerivOrigin
DefaultOrigin
DoOrigin
DoPatOrigin (LPat GhcRn)
MCompOrigin
MCompPatOrigin (LPat GhcRn)
ProcOrigin
ArrowCmdOrigin
AnnOrigin
FunDepOrigin1 PredType CtOrigin RealSrcSpan PredType CtOrigin RealSrcSpan
FunDepOrigin2 PredType CtOrigin PredType SrcSpan
ExprHoleOrigin OccName
TypeHoleOrigin OccName
PatCheckOrigin
ListOrigin
IfThenElseOrigin
BracketOrigin
StaticOrigin
Shouldn'tHappenOrigin String
InstProvidedOrigin	Testing whether the constraint associated with an instance declaration in a signature file is satisfied upon instantiation. Test cases: backpackshould_failbkpfail{11,43}.bkp
Fields Module Module in which the instance was declared ClsInst The declared typeclass instance
NonLinearPatternOrigin
UsageEnvironmentOf Name
CycleBreakerOrigin CtOrigin
FixedRuntimeRepOrigin
Fields !Type The type being checked for representation polymorphism. We record it here for access in `mkFRRErr`. !FRROrigin

Instances

Instances details

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

exprCtOrigin :: HsExpr GhcRn -> CtOrigin Source #

lexprCtOrigin :: LHsExpr GhcRn -> CtOrigin Source #

Extract a suitable CtOrigin from a HsExpr

matchesCtOrigin :: MatchGroup GhcRn (LHsExpr GhcRn) -> CtOrigin Source #

Extract a suitable CtOrigin from a MatchGroup

grhssCtOrigin :: GRHSs GhcRn (LHsExpr GhcRn) -> CtOrigin Source #

Extract a suitable CtOrigin from guarded RHSs

isVisibleOrigin :: CtOrigin -> Bool Source #

toInvisibleOrigin :: CtOrigin -> CtOrigin Source #

pprCtOrigin :: CtOrigin -> SDoc Source #

isGivenOrigin :: CtOrigin -> Bool Source #

data TypedThing Source #

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

HsTypeRnThing (HsType GhcRn)
TypeThing Type
HsExprRnThing (HsExpr GhcRn)
NameThing Name

Instances

Instances details

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

data TyVarBndrs Source #

Some kind of type variable binder.

Used for reporting errors, in SkolemInfo and TcReportMsg.

Constructors

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

Instances

Instances details

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

isPushCallStackOrigin :: CtOrigin -> Bool Source #

callStackOriginFS :: CtOrigin -> FastString Source #

data FRROrigin Source #

Where are we checking that a type has a fixed runtime representation? Equivalently: what is the origin of an emitted 'Concrete#' constraint?

Constructors

FRRApp !(HsExpr GhcRn)	Function arguments must have a fixed runtime representation. Test case: RepPolyApp.
FRRRecordUpdate !RdrName !(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.
FRRMatch !(HsMatchContext GhcTc) !Int	The type of a pattern in a match group must have a fixed runtime representation. This rules out: - individual patterns which don't have a fixed runtime representation, - a representation-polymorphic empty case statement, - representation-polymorphic GADT pattern matches in which individual pattern types have a fixed runtime representation. Test cases: RepPolyRecordPattern, RepPolyUnboxedPatterns, RepPolyBinder, RepPolyWildcardPattern, RepPolyMatch, RepPolyNPlusK, RepPolyPatBind, T20426.
FRRDataConArg !DataCon !Int	An instantiation of a newtype/data constructor in which one of the remaining arguments types does not have a fixed runtime representation. Test case: UnliftedNewtypesLevityBinder.
FRRNoBindingResArg !Id !Int	An instantiation of an `Id` with no binding (e.g. `coerce`, `unsafeCoerce#`) in which one of the remaining arguments types does not have a fixed runtime representation. Test cases: RepPolyWrappedVar, T14561, UnliftedNewtypesCoerceFail.
FRRTupleArg !Int	Arguments to unboxed tuples must have fixed runtime representations. Test case: RepPolyTuple.
FRRTupleSection !Int	Tuple sections must have a fixed runtime representation. Test case: RepPolyTupleSection.
FRRUnboxedSum	Unboxed sums must have a fixed runtime representation. 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 comprehesion 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 !FRRArrowOrigin	A representation-polymorphism check arising from arrow notation. See `FRRArrowOrigin` for more details.
FRRWpFun !WpFunOrigin	A representation-polymorphic check arising from an `HsWrapper`. See `WpFunOrigin` for more details.

Instances

Instances details

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

pprFRROrigin :: FRROrigin -> SDoc Source #

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 added by mkFRRErr.

data StmtOrigin Source #

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.

Constructors

MonadComprehension
DoNotation

Instances

Instances details

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

data FRRArrowOrigin Source #

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

See FRROrigin 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.
ArrowCmdLam !Int	A pattern in an arrow command abstraction 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.

Instances

Instances details

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

pprFRRArrowOrigin :: FRRArrowOrigin -> SDoc Source #

data WpFunOrigin Source #

While typechecking a WpFun HsWrapper, in which context did a representation polymorphism check arise?

See FRROrigin for more general origins of representation polymorphism checks.

Constructors

WpFunSyntaxOp !CtOrigin
WpFunViewPat !(HsExpr GhcRn)
WpFunFunTy !Type
WpFunFunExpTy !ExpType

Instances

Instances details

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

pprWpFunOrigin :: WpFunOrigin -> SDoc Source #

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

SigSkol UserTypeCtxt TcType [(Name, TcTyVar)]
SigTypeSkol UserTypeCtxt
ForAllSkol TyVarBndrs
DerivSkol Type
InstSkol
FamInstSkol
PatSkol ConLike (HsMatchContext GhcTc)
IPSkol [HsIPName]
RuleSkol RuleName
InferSkol [(Name, TcType)]
BracketSkol
UnifyForAllSkol TcType
TyConSkol TyConFlavour Name
DataConSkol Name
ReifySkol
QuantCtxtSkol
RuntimeUnkSkol
ArrowReboundIfSkol
UnkSkol CallStack