TcRnTypes

Documentation

type TcRnIf a b = IOEnv (Env a b)

type TcRn = TcRnIf TcGblEnv TcLclEnv

type TcM = TcRn

Historical "type-checking monad" (now it's just TcRn).

type RnM = TcRn

Historical "renaming monad" (now it's just TcRn).

type IfM lcl = TcRnIf IfGblEnv lcl

type IfL = IfM IfLclEnv

type IfG = IfM ()

type TcRef a = IORef a

Type alias for IORef; the convention is we'll use this for mutable bits of data in TcGblEnv which are updated during typechecking and returned at the end.

data Env gbl lcl

Constructors

Env

Fields

• env_top :: HscEnv
• env_us :: !(IORef UniqSupply)
• env_gbl :: gbl
• env_lcl :: lcl

Instances

ContainsModule gbl => ContainsModule (Env gbl lcl)

Methods

extractModule :: Env gbl lcl -> Module

ContainsDynFlags (Env gbl lcl)

Methods

extractDynFlags :: Env gbl lcl -> DynFlags

data TcGblEnv

TcGblEnv describes the top-level of the module at the point at which the typechecker is finished work. It is this structure that is handed on to the desugarer For state that needs to be updated during the typechecking phase and returned at end, use a TcRef (= IORef).

Constructors

TcGblEnv

Fields

• tcg_mod :: Module

  Module being compiled

• tcg_semantic_mod :: Module

  If a signature, the backing module See also Note [Identity versus semantic module]

• tcg_src :: HscSource

  What kind of module (regular Haskell, hs-boot, hsig)

• tcg_rdr_env :: GlobalRdrEnv

  Top level envt; used during renaming

• tcg_default :: Maybe [Type]

  Types used for defaulting. Nothing => no default decl

• tcg_fix_env :: FixityEnv

  Just for things in this module

• tcg_field_env :: RecFieldEnv

  Just for things in this module See Note [The interactive package] in HscTypes

• tcg_type_env :: TypeEnv

  Global type env for the module we are compiling now. All TyCons and Classes (for this module) end up in here right away, along with their derived constructors, selectors.

  (Ids defined in this module start in the local envt, though they move to the global envt during zonking)

  NB: for what "things in this module" means, see Note [The interactive package] in HscTypes

• tcg_type_env_var :: TcRef TypeEnv
• tcg_inst_env :: InstEnv

  Instance envt for all home-package modules; Includes the dfuns in tcg_insts

• tcg_fam_inst_env :: FamInstEnv

  Ditto for family instances

• tcg_ann_env :: AnnEnv

  And for annotations

• tcg_pending_fam_checks :: NameEnv [([FamInst], FamInstEnv)]

  Family instances we have to check for consistency. Invariant: each FamInst in the list's fi_fam matches the key of the entry in the NameEnv. This gets consumed by checkRecFamInstConsistency. See Note [Don't check hs-boot type family instances too early]

• tcg_exports :: [AvailInfo]

  What is exported

• tcg_imports :: ImportAvails

  Information about what was imported from where, including things bound in this module. Also store Safe Haskell info here about transative trusted packaage requirements.

• tcg_dus :: DefUses

  What is defined in this module and what is used.

• tcg_used_gres :: TcRef [GlobalRdrElt]

  Records occurrences of imported entities See Note [Tracking unused binding and imports]

• tcg_keep :: TcRef NameSet

  Locally-defined top-level names to keep alive.

  "Keep alive" means give them an Exported flag, so that the simplifier does not discard them as dead code, and so that they are exposed in the interface file (but not to export to the user).

  Some things, like dict-fun Ids and default-method Ids are "born" with the Exported flag on, for exactly the above reason, but some we only discover as we go. Specifically:

  • The to/from functions for generic data types
  • Top-level variables appearing free in the RHS of an orphan rule
  • Top-level variables appearing free in a TH bracket
• tcg_th_used :: TcRef Bool

  True = Template Haskell syntax used.

  We need this so that we can generate a dependency on the Template Haskell package, because the desugarer is going to emit loads of references to TH symbols. The reference is implicit rather than explicit, so we have to zap a mutable variable.

• tcg_th_splice_used :: TcRef Bool

  True = A Template Haskell splice was used.

  Splices disable recompilation avoidance (see #481)

• tcg_th_top_level_locs :: TcRef (Set RealSrcSpan)

  Locations of the top-level splices; used for providing details on scope in error messages for out-of-scope variables

• tcg_dfun_n :: TcRef OccSet

  Allows us to choose unique DFun names.

• tcg_merged :: [(Module, Fingerprint)]

  The requirements we merged with; we always have to recompile if any of these changed.

• tcg_rn_exports :: Maybe [Located (IE Name)]
• tcg_rn_imports :: [LImportDecl Name]
• tcg_rn_decls :: Maybe (HsGroup Name)

  Renamed decls, maybe. Nothing = Don't retain renamed decls.

• tcg_dependent_files :: TcRef [FilePath]

  dependencies from addDependentFile

• tcg_th_topdecls :: TcRef [LHsDecl RdrName]

  Top-level declarations from addTopDecls

• tcg_th_foreign_files :: TcRef [(ForeignSrcLang, String)]

  Foreign files emitted from TH.

• tcg_th_topnames :: TcRef NameSet

  Exact names bound in top-level declarations in tcg_th_topdecls

• tcg_th_modfinalizers :: TcRef [TcM ()]

  Template Haskell module finalizers.

  They are computations in the TcM monad rather than Q because we set them to use particular local environments.

• tcg_th_state :: TcRef (Map TypeRep Dynamic)
• tcg_th_remote_state :: TcRef (Maybe (ForeignRef (IORef QState)))

  Template Haskell state

• tcg_ev_binds :: Bag EvBind
• tcg_tr_module :: Maybe Id
• tcg_binds :: LHsBinds Id
• tcg_sigs :: NameSet
• tcg_imp_specs :: [LTcSpecPrag]
• tcg_warns :: Warnings
• tcg_anns :: [Annotation]
• tcg_tcs :: [TyCon]
• tcg_insts :: [ClsInst]
• tcg_fam_insts :: [FamInst]
• tcg_rules :: [LRuleDecl Id]
• tcg_fords :: [LForeignDecl Id]
• tcg_vects :: [LVectDecl Id]
• tcg_patsyns :: [PatSyn]
• tcg_doc_hdr :: Maybe LHsDocString

  Maybe Haddock header docs

• tcg_hpc :: AnyHpcUsage

  True if any part of the prog uses hpc instrumentation.

• tcg_self_boot :: SelfBootInfo

  Whether this module has a corresponding hi-boot file

• tcg_main :: Maybe Name

  The Name of the main function, if this module is the main module.

• tcg_safeInfer :: TcRef (Bool, WarningMessages)

  Has the typechecker inferred this module as -XSafe (Safe Haskell) See Note [Safe Haskell Overlapping Instances Implementation], although this is used for more than just that failure case.

• tcg_tc_plugins :: [TcPluginSolver]

  A list of user-defined plugins for the constraint solver.

• tcg_top_loc :: RealSrcSpan

  The RealSrcSpan this module came from

• tcg_static_wc :: TcRef WantedConstraints

  Wanted constraints of static forms. See Note [Constraints in static forms].

• tcg_complete_matches :: [CompleteMatch]

Instances

ContainsModule TcGblEnv

Methods

extractModule :: TcGblEnv -> Module

data TcLclEnv

Constructors

TcLclEnv

Fields

• tcl_loc :: RealSrcSpan
• tcl_ctxt :: [ErrCtxt]
• tcl_tclvl :: TcLevel
• tcl_th_ctxt :: ThStage
• tcl_th_bndrs :: ThBindEnv
• tcl_arrow_ctxt :: ArrowCtxt
• tcl_rdr :: LocalRdrEnv
• tcl_env :: TcTypeEnv
• tcl_bndrs :: TcIdBinderStack
• tcl_tidy :: TidyEnv
• tcl_tyvars :: TcRef TcTyVarSet
• tcl_lie :: TcRef WantedConstraints
• tcl_errs :: TcRef Messages

data IfGblEnv

Constructors

IfGblEnv

Fields

• if_doc :: SDoc
• if_rec_types :: Maybe (Module, IfG TypeEnv)

data IfLclEnv

Constructors

IfLclEnv

Fields

• if_mod :: Module
• if_boot :: Bool
• if_loc :: SDoc
• if_nsubst :: Maybe NameShape
• if_implicits_env :: Maybe TypeEnv
• if_tv_env :: FastStringEnv TyVar
• if_id_env :: FastStringEnv Id

tcVisibleOrphanMods :: TcGblEnv -> ModuleSet

data FrontendResult

FrontendResult describes the result of running the frontend of a Haskell module. Usually, you'll get a FrontendTypecheck, since running the frontend involves typechecking a program, but for an hs-boot merge you'll just get a ModIface, since no actual typechecking occurred.

This data type really should be in HscTypes, but it needs to have a TcGblEnv which is only defined here.

Constructors

FrontendTypecheck TcGblEnv

type ErrCtxt = (Bool, TidyEnv -> TcM (TidyEnv, MsgDoc))

type RecFieldEnv = NameEnv [FieldLabel]

data ImportAvails

ImportAvails summarises what was imported from where, irrespective of whether the imported things are actually used or not. It is used:

• when processing the export list,
• when constructing usage info for the interface file,
• to identify the list of directly imported modules for initialisation purposes and for optimised overlap checking of family instances,
• when figuring out what things are really unused

Constructors

ImportAvails

Fields

• imp_mods :: ImportedMods

  Domain is all directly-imported modules

  See the documentation on ImportedModsVal in HscTypes for the meaning of the fields.

  We need a full ModuleEnv rather than a ModuleNameEnv here, because we might be importing modules of the same name from different packages. (currently not the case, but might be in the future).

• imp_dep_mods :: ModuleNameEnv (ModuleName, IsBootInterface)

  Home-package modules needed by the module being compiled

  It doesn't matter whether any of these dependencies are actually used when compiling the module; they are listed if they are below it at all. For example, suppose M imports A which imports X. Then compiling M might not need to consult X.hi, but X is still listed in M's dependencies.

• imp_dep_pkgs :: Set InstalledUnitId

  Packages needed by the module being compiled, whether directly, or via other modules in this package, or via modules imported from other packages.

• imp_trust_pkgs :: Set InstalledUnitId

  This is strictly a subset of imp_dep_pkgs and records the packages the current module needs to trust for Safe Haskell compilation to succeed. A package is required to be trusted if we are dependent on a trustworthy module in that package. While perhaps making imp_dep_pkgs a tuple of (UnitId, Bool) where True for the bool indicates the package is required to be trusted is the more logical design, doing so complicates a lot of code not concerned with Safe Haskell. See Note [RnNames . Tracking Trust Transitively]

• imp_trust_own_pkg :: Bool

  Do we require that our own package is trusted? This is to handle efficiently the case where a Safe module imports a Trustworthy module that resides in the same package as it. See Note [RnNames . Trust Own Package]

• imp_orphs :: [Module]

  Orphan modules below us in the import tree (and maybe including us for imported modules)

• imp_finsts :: [Module]

  Family instance modules below us in the import tree (and maybe including us for imported modules)

emptyImportAvails :: ImportAvails

plusImportAvails :: ImportAvails -> ImportAvails -> ImportAvails

Union two ImportAvails

This function is a key part of Import handling, basically for each import we create a separate ImportAvails structure and then union them all together with this function.

data WhereFrom

Constructors

ImportByUser IsBootInterface

ImportBySystem

ImportByPlugin

Instances

Outputable WhereFrom

Methods

ppr :: WhereFrom -> SDoc

pprPrec :: Rational -> WhereFrom -> SDoc

mkModDeps :: [(ModuleName, IsBootInterface)] -> ModuleNameEnv (ModuleName, IsBootInterface)

modDepsElts :: ModuleNameEnv (ModuleName, IsBootInterface) -> [(ModuleName, IsBootInterface)]

type TcTypeEnv = NameEnv TcTyThing

type TcIdBinderStack = [TcIdBinder]

data TcIdBinder

Constructors

TcIdBndr TcId TopLevelFlag

TcIdBndr_ExpType Name ExpType TopLevelFlag

Instances

Outputable TcIdBinder

Methods

ppr :: TcIdBinder -> SDoc

pprPrec :: Rational -> TcIdBinder -> SDoc

HasOccName TcIdBinder

Methods

occName :: TcIdBinder -> OccName

data TcTyThing

A typecheckable thing available in a local context. Could be AGlobal TyThing, but also lexically scoped variables, etc. See TcEnv for how to retrieve a TyThing given a Name.

Constructors

AGlobal TyThing

ATcId

Fields

• tct_id :: TcId
• tct_info :: IdBindingInfo

ATyVar Name TcTyVar

ATcTyCon TyCon

APromotionErr PromotionErr

Instances

Outputable TcTyThing

Methods

ppr :: TcTyThing -> SDoc

pprPrec :: Rational -> TcTyThing -> SDoc

data PromotionErr

Constructors

TyConPE

ClassPE

FamDataConPE

PatSynPE

RecDataConPE

NoDataKindsTC

NoDataKindsDC

NoTypeInTypeTC

NoTypeInTypeDC

Instances

Outputable PromotionErr

Methods

ppr :: PromotionErr -> SDoc

pprPrec :: Rational -> PromotionErr -> SDoc

data IdBindingInfo

IdBindingInfo describes how an Id is bound.

It is used for the following purposes: a) for static forms in TcExpr.checkClosedInStaticForm and b) to figure out when a nested binding can be generalised, in TcBinds.decideGeneralisationPlan.

Constructors

NotLetBound

ClosedLet

NonClosedLet RhsNames ClosedTypeId

Instances

Outputable IdBindingInfo

Methods

ppr :: IdBindingInfo -> SDoc

pprPrec :: Rational -> IdBindingInfo -> SDoc

type ClosedTypeId = Bool

type RhsNames = NameSet

data IsGroupClosed

IsGroupClosed describes a group of mutually-recursive bindings

Constructors

IsGroupClosed (NameEnv RhsNames) ClosedTypeId

data SelfBootInfo

Constructors

NoSelfBoot

SelfBoot

Fields

• sb_mds :: ModDetails
• sb_tcs :: NameSet

pprTcTyThingCategory :: TcTyThing -> SDoc

pprPECategory :: PromotionErr -> SDoc

data CompleteMatch

A list of conlikes which represents a complete pattern match. These arise from COMPLETE signatures.

Constructors

CompleteMatch

Fields

• completeMatchConLikes :: [Name]

  The ConLikes that form a covering family (e.g. Nothing, Just)

• completeMatchTyCon :: Name

  The TyCon that they cover (e.g. Maybe)

Instances

Outputable CompleteMatch

Methods

ppr :: CompleteMatch -> SDoc

pprPrec :: Rational -> CompleteMatch -> SDoc

type DsM = TcRnIf DsGblEnv DsLclEnv

data DsLclEnv

Constructors

DsLclEnv

Fields

• dsl_meta :: DsMetaEnv
• dsl_loc :: RealSrcSpan
• dsl_dicts :: Bag EvVar
• dsl_tm_cs :: Bag SimpleEq
• dsl_pm_iter :: IORef Int

data DsGblEnv

Constructors

DsGblEnv

Fields

• ds_mod :: Module
• ds_fam_inst_env :: FamInstEnv
• ds_unqual :: PrintUnqualified
• ds_msgs :: IORef Messages
• ds_if_env :: (IfGblEnv, IfLclEnv)
• ds_dph_env :: GlobalRdrEnv
• ds_parr_bi :: PArrBuiltin
• ds_complete_matches :: CompleteMatchMap

Instances

ContainsModule DsGblEnv

Methods

extractModule :: DsGblEnv -> Module

data PArrBuiltin

Constructors

PArrBuiltin

Fields

• lengthPVar :: Var

  lengthP

• replicatePVar :: Var

  replicateP

• singletonPVar :: Var

  singletonP

• mapPVar :: Var

  mapP

• filterPVar :: Var

  filterP

• zipPVar :: Var

  zipP

• crossMapPVar :: Var

  crossMapP

• indexPVar :: Var

  (!:)

• emptyPVar :: Var

  emptyP

• appPVar :: Var

  (+:+)

• enumFromToPVar :: Var

  enumFromToP

• enumFromThenToPVar :: Var

  enumFromThenToP

type DsMetaEnv = NameEnv DsMetaVal

data DsMetaVal

Constructors

DsBound Id

DsSplice (HsExpr Id)

type CompleteMatchMap = UniqFM [CompleteMatch]

A map keyed by the completeMatchTyCon.

mkCompleteMatchMap :: [CompleteMatch] -> CompleteMatchMap

extendCompleteMatchMap :: CompleteMatchMap -> [CompleteMatch] -> CompleteMatchMap

data ThStage

Constructors

Splice SpliceType

RunSplice (TcRef [ForeignRef (Q ())])

Comp

Brack ThStage PendingStuff

Instances

Outputable ThStage

Methods

ppr :: ThStage -> SDoc

pprPrec :: Rational -> ThStage -> SDoc

data SpliceType

Constructors

Typed

Untyped

data PendingStuff

Constructors

RnPendingUntyped (TcRef [PendingRnSplice])

RnPendingTyped

TcPending (TcRef [PendingTcSplice]) (TcRef WantedConstraints)

topStage :: ThStage

topAnnStage :: ThStage

topSpliceStage :: ThStage

type ThLevel = Int

impLevel :: ThLevel

outerLevel :: ThLevel

thLevel :: ThStage -> ThLevel

data ForeignSrcLang :: *

Constructors

LangC

LangCxx

LangObjc

LangObjcxx

Instances

Eq ForeignSrcLang

Methods

(==) :: ForeignSrcLang -> ForeignSrcLang -> Bool

(/=) :: ForeignSrcLang -> ForeignSrcLang -> Bool

Show ForeignSrcLang

Methods

showsPrec :: Int -> ForeignSrcLang -> ShowS

show :: ForeignSrcLang -> String

showList :: [ForeignSrcLang] -> ShowS

Generic ForeignSrcLang

Associated Types

type Rep ForeignSrcLang :: * -> *

Methods

from :: ForeignSrcLang -> Rep ForeignSrcLang x

to :: Rep ForeignSrcLang x -> ForeignSrcLang

type Rep ForeignSrcLang

type Rep ForeignSrcLang = D1 * (MetaData "ForeignSrcLang" "GHC.ForeignSrcLang.Type" "ghc-boot-th-8.2.2" False) ((:+:) * ((:+:) * (C1 * (MetaCons "LangC" PrefixI False) (U1 *)) (C1 * (MetaCons "LangCxx" PrefixI False) (U1 *))) ((:+:) * (C1 * (MetaCons "LangObjc" PrefixI False) (U1 *)) (C1 * (MetaCons "LangObjcxx" PrefixI False) (U1 *))))

data ArrowCtxt

Constructors

NoArrowCtxt

ArrowCtxt LocalRdrEnv (TcRef WantedConstraints)

type TcSigFun = Name -> Maybe TcSigInfo

data TcSigInfo

Constructors

TcIdSig TcIdSigInfo

TcPatSynSig TcPatSynInfo

Instances

Outputable TcSigInfo

Methods

ppr :: TcSigInfo -> SDoc

pprPrec :: Rational -> TcSigInfo -> SDoc

data TcIdSigInfo

Constructors

CompleteSig

Fields

• sig_bndr :: TcId
• sig_ctxt :: UserTypeCtxt
• sig_loc :: SrcSpan

PartialSig

Fields

• psig_name :: Name
• psig_hs_ty :: LHsSigWcType Name
• sig_ctxt :: UserTypeCtxt
• sig_loc :: SrcSpan

Instances

Outputable TcIdSigInfo

Methods

ppr :: TcIdSigInfo -> SDoc

pprPrec :: Rational -> TcIdSigInfo -> SDoc

data TcIdSigInst

Constructors

TISI

Fields

• sig_inst_sig :: TcIdSigInfo
• sig_inst_skols :: [(Name, TcTyVar)]
• sig_inst_theta :: TcThetaType
• sig_inst_tau :: TcSigmaType
• sig_inst_wcs :: [(Name, TcTyVar)]
• sig_inst_wcx :: Maybe TcTyVar

Instances

Outputable TcIdSigInst

Methods

ppr :: TcIdSigInst -> SDoc

pprPrec :: Rational -> TcIdSigInst -> SDoc

data TcPatSynInfo

Constructors

TPSI

Fields

• patsig_name :: Name
• patsig_implicit_bndrs :: [TyVarBinder]
• patsig_univ_bndrs :: [TyVar]
• patsig_req :: TcThetaType
• patsig_ex_bndrs :: [TyVar]
• patsig_prov :: TcThetaType
• patsig_body_ty :: TcSigmaType

Instances

Outputable TcPatSynInfo

Methods

ppr :: TcPatSynInfo -> SDoc

pprPrec :: Rational -> TcPatSynInfo -> SDoc

isPartialSig :: TcIdSigInst -> Bool

hasCompleteSig :: TcSigFun -> Name -> Bool

No signature or a partial signature

type Xi = Type

data Ct

Constructors

CDictCan

Fields

• cc_ev :: CtEvidence
• cc_class :: Class
• cc_tyargs :: [Xi]
• cc_pend_sc :: Bool

CIrredEvCan

Fields

• cc_ev :: CtEvidence

CTyEqCan

Fields

• cc_ev :: CtEvidence
• cc_tyvar :: TcTyVar
• cc_rhs :: TcType
• cc_eq_rel :: EqRel

CFunEqCan

Fields

• cc_ev :: CtEvidence
• cc_fun :: TyCon
• cc_tyargs :: [Xi]
• cc_fsk :: TcTyVar

CNonCanonical

Fields

• cc_ev :: CtEvidence

CHoleCan

Fields

• cc_ev :: CtEvidence
• cc_hole :: Hole

Instances

Outputable Ct

Methods

ppr :: Ct -> SDoc

pprPrec :: Rational -> Ct -> SDoc

type Cts = Bag Ct

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

isCTyEqCan :: Ct -> Bool

isCFunEqCan :: Ct -> Bool

isPendingScDict :: Ct -> Maybe Ct

superClassesMightHelp :: Ct -> 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]

isCDictCan_Maybe :: Ct -> Maybe Class

isCFunEqCan_maybe :: Ct -> Maybe (TyCon, [Type])

isCIrredEvCan :: Ct -> Bool

isCNonCanonical :: Ct -> Bool

isWantedCt :: Ct -> Bool

isDerivedCt :: Ct -> Bool

isGivenCt :: Ct -> Bool

isHoleCt :: Ct -> Bool

isOutOfScopeCt :: Ct -> Bool

isExprHoleCt :: Ct -> Bool

isTypeHoleCt :: Ct -> Bool

isUserTypeErrorCt :: Ct -> Bool

getUserTypeErrorMsg :: Ct -> Maybe Type

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

ctLoc :: Ct -> CtLoc

setCtLoc :: Ct -> CtLoc -> Ct

ctPred :: Ct -> PredType

ctFlavour :: Ct -> CtFlavour

Get the flavour of the given Ct

ctEqRel :: Ct -> EqRel

Get the equality relation for the given Ct

ctOrigin :: Ct -> CtOrigin

mkTcEqPredLikeEv :: CtEvidence -> TcType -> TcType -> TcType

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

mkNonCanonical :: CtEvidence -> Ct

mkNonCanonicalCt :: Ct -> Ct

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

ctEvPred :: CtEvidence -> TcPredType

ctEvLoc :: CtEvidence -> CtLoc

ctEvOrigin :: CtEvidence -> CtOrigin

ctEvEqRel :: CtEvidence -> EqRel

Get the equality relation relevant for a CtEvidence

ctEvTerm :: CtEvidence -> EvTerm

ctEvCoercion :: CtEvidence -> Coercion

ctEvId :: CtEvidence -> TcId

tyCoVarsOfCt :: Ct -> TcTyCoVarSet

Returns free variables of constraints as a non-deterministic set

tyCoVarsOfCts :: Cts -> TcTyCoVarSet

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

tyCoVarsOfCtList :: Ct -> [TcTyCoVar]

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

tyCoVarsOfCtsList :: Cts -> [TcTyCoVar]

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

data WantedConstraints

Constructors

WC

Fields

• wc_simple :: Cts
• wc_impl :: Bag Implication
• wc_insol :: Cts

Instances

Outputable WantedConstraints

Methods

ppr :: WantedConstraints -> SDoc

pprPrec :: Rational -> WantedConstraints -> SDoc

insolubleWC :: WantedConstraints -> Bool

emptyWC :: WantedConstraints

isEmptyWC :: WantedConstraints -> Bool

andWC :: WantedConstraints -> WantedConstraints -> WantedConstraints

unionsWC :: [WantedConstraints] -> WantedConstraints

mkSimpleWC :: [CtEvidence] -> WantedConstraints

mkImplicWC :: Bag Implication -> WantedConstraints

addInsols :: WantedConstraints -> Bag Ct -> WantedConstraints

getInsolubles :: WantedConstraints -> Cts

insolublesOnly :: WantedConstraints -> WantedConstraints

addSimples :: WantedConstraints -> Bag Ct -> WantedConstraints

addImplics :: WantedConstraints -> Bag Implication -> WantedConstraints

tyCoVarsOfWC :: WantedConstraints -> TyCoVarSet

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

dropDerivedWC :: WantedConstraints -> WantedConstraints

dropDerivedSimples :: Cts -> Cts

dropDerivedInsols :: Cts -> Cts

tyCoVarsOfWCList :: WantedConstraints -> [TyCoVar]

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

trulyInsoluble :: Ct -> Bool

isDroppableDerivedLoc :: CtLoc -> Bool

insolubleImplic :: Implication -> Bool

arisesFromGivens :: Ct -> Bool

data Implication

Constructors

Implic

Fields

• ic_tclvl :: TcLevel
• ic_skols :: [TcTyVar]
• ic_info :: SkolemInfo
• ic_given :: [EvVar]
• ic_no_eqs :: Bool
• ic_env :: TcLclEnv
• ic_wanted :: WantedConstraints
• ic_binds :: EvBindsVar
• ic_needed :: VarSet
• ic_status :: ImplicStatus

Instances

Outputable Implication

Methods

ppr :: Implication -> SDoc

pprPrec :: Rational -> Implication -> SDoc

data ImplicStatus

Constructors

IC_Solved

Fields

• ics_need :: VarSet
• ics_dead :: [EvVar]

IC_Insoluble

IC_Unsolved

Instances

Outputable ImplicStatus

Methods

ppr :: ImplicStatus -> SDoc

pprPrec :: Rational -> ImplicStatus -> SDoc

isInsolubleStatus :: ImplicStatus -> Bool

isSolvedStatus :: ImplicStatus -> Bool

data SubGoalDepth

See Note [SubGoalDepth]

Instances

Eq SubGoalDepth

Methods

(==) :: SubGoalDepth -> SubGoalDepth -> Bool

(/=) :: SubGoalDepth -> SubGoalDepth -> Bool

Ord SubGoalDepth

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

Outputable SubGoalDepth

Methods

ppr :: SubGoalDepth -> SDoc

pprPrec :: Rational -> SubGoalDepth -> SDoc

initialSubGoalDepth :: SubGoalDepth

maxSubGoalDepth :: SubGoalDepth -> SubGoalDepth -> SubGoalDepth

bumpSubGoalDepth :: SubGoalDepth -> SubGoalDepth

subGoalDepthExceeded :: DynFlags -> SubGoalDepth -> Bool

data CtLoc

Constructors

CtLoc

Fields

• 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

setCtLocOrigin :: CtLoc -> CtOrigin -> CtLoc

setCtLocEnv :: CtLoc -> TcLclEnv -> CtLoc

setCtLocSpan :: CtLoc -> RealSrcSpan -> CtLoc

data CtOrigin

Constructors

GivenOrigin SkolemInfo

OccurrenceOf Name

OccurrenceOfRecSel RdrName

AppOrigin

SpecPragOrigin UserTypeCtxt

TypeEqOrigin

Fields

• uo_actual :: TcType
• uo_expected :: TcType
• uo_thing :: Maybe ErrorThing

  The thing that has type "actual"

KindEqOrigin TcType (Maybe TcType) CtOrigin (Maybe TypeOrKind)

IPOccOrigin HsIPName

OverLabelOrigin FastString

LiteralOrigin (HsOverLit Name)

NegateOrigin

ArithSeqOrigin (ArithSeqInfo Name)

PArrSeqOrigin (ArithSeqInfo Name)

SectionOrigin

TupleOrigin

ExprSigOrigin

PatSigOrigin

PatOrigin

ProvCtxtOrigin (PatSynBind Name Name)

RecordUpdOrigin

ViewPatOrigin

ScOrigin TypeSize

DerivOrigin

DerivOriginDC DataCon Int

DerivOriginCoerce Id Type Type

StandAloneDerivOrigin

DefaultOrigin

DoOrigin

DoPatOrigin (LPat Name)

MCompOrigin

MCompPatOrigin (LPat Name)

IfOrigin

ProcOrigin

AnnOrigin

FunDepOrigin1 PredType CtLoc PredType CtLoc

FunDepOrigin2 PredType CtOrigin PredType SrcSpan

HoleOrigin

UnboundOccurrenceOf OccName

ListOrigin

StaticOrigin

FailablePattern (LPat TcId)

Shouldn'tHappenOrigin String

InstProvidedOrigin Module ClsInst

Instances

Outputable CtOrigin

Methods

ppr :: CtOrigin -> SDoc

pprPrec :: Rational -> CtOrigin -> SDoc

exprCtOrigin :: HsExpr Name -> CtOrigin

lexprCtOrigin :: LHsExpr Name -> CtOrigin

Extract a suitable CtOrigin from a HsExpr

matchesCtOrigin :: MatchGroup Name (LHsExpr Name) -> CtOrigin

Extract a suitable CtOrigin from a MatchGroup

grhssCtOrigin :: GRHSs Name (LHsExpr Name) -> CtOrigin

Extract a suitable CtOrigin from guarded RHSs

data ErrorThing

A thing that can be stored for error message generation only. It is stored with a function to zonk and tidy the thing.

Constructors

Outputable a => ErrorThing a (Maybe Arity) (TidyEnv -> a -> TcM (TidyEnv, a))

Instances

Outputable ErrorThing

Methods

ppr :: ErrorThing -> SDoc

pprPrec :: Rational -> ErrorThing -> SDoc

mkErrorThing :: Outputable a => a -> ErrorThing

Make an ErrorThing that doesn't need tidying or zonking

errorThingNumArgs_maybe :: ErrorThing -> Maybe Arity

Retrieve the # of arguments in the error thing, if known

data TypeOrKind

Flag to see whether we're type-checking terms or kind-checking types

Constructors

TypeLevel

KindLevel

Instances

Eq TypeOrKind

Methods

(==) :: TypeOrKind -> TypeOrKind -> Bool

(/=) :: TypeOrKind -> TypeOrKind -> Bool

Outputable TypeOrKind

Methods

ppr :: TypeOrKind -> SDoc

pprPrec :: Rational -> TypeOrKind -> SDoc

isTypeLevel :: TypeOrKind -> Bool

isKindLevel :: TypeOrKind -> Bool

pprCtOrigin :: CtOrigin -> SDoc

pprCtLoc :: CtLoc -> SDoc

pushErrCtxt :: CtOrigin -> ErrCtxt -> CtLoc -> CtLoc

pushErrCtxtSameOrigin :: ErrCtxt -> CtLoc -> CtLoc

data SkolemInfo

Constructors

SigSkol UserTypeCtxt TcType [(Name, TcTyVar)]

ClsSkol Class

DerivSkol Type

InstSkol

InstSC TypeSize

DataSkol

FamInstSkol

PatSkol ConLike (HsMatchContext Name)

ArrowSkol

IPSkol [HsIPName]

RuleSkol RuleName

InferSkol [(Name, TcType)]

BracketSkol

UnifyForAllSkol TcType

UnkSkol

Instances

Outputable SkolemInfo

Methods

ppr :: SkolemInfo -> SDoc

pprPrec :: Rational -> SkolemInfo -> SDoc

pprSigSkolInfo :: UserTypeCtxt -> TcType -> SDoc

pprSkolInfo :: SkolemInfo -> SDoc

termEvidenceAllowed :: SkolemInfo -> Bool

data CtEvidence

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

Outputable CtEvidence

Methods

ppr :: CtEvidence -> SDoc

pprPrec :: Rational -> CtEvidence -> SDoc

data TcEvDest

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 TyCoRep

Instances

Outputable TcEvDest

Methods

ppr :: TcEvDest -> SDoc

pprPrec :: Rational -> TcEvDest -> SDoc

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

mkKindLoc :: TcType -> TcType -> CtLoc -> CtLoc

toKindLoc :: CtLoc -> CtLoc

Take a CtLoc and moves it to the kind level

isWanted :: CtEvidence -> Bool

isGiven :: CtEvidence -> Bool

isDerived :: CtEvidence -> Bool

isGivenOrWDeriv :: CtFlavour -> Bool

ctEvRole :: CtEvidence -> Role

Get the role relevant for a CtEvidence

data TcPlugin

Constructors

TcPlugin

Fields

• tcPluginInit :: TcPluginM s

  Initialize plugin, when entering type-checker.

• tcPluginSolve :: s -> TcPluginSolver

  Solve some constraints. TODO: WRITE MORE DETAILS ON HOW THIS WORKS.

• tcPluginStop :: s -> TcPluginM ()

  Clean up after the plugin, when exiting the type-checker.

data TcPluginResult

Constructors

TcPluginContradiction [Ct]

The plugin found a contradiction. The returned constraints are removed from the inert set, and recorded as insoluble.

TcPluginOk [(EvTerm, Ct)] [Ct]

The first field is for constraints that were solved. These are removed from the inert set, and the evidence for them is recorded. The second field contains new work, that should be processed by the constraint solver.

type TcPluginSolver = [Ct] -> [Ct] -> [Ct] -> TcPluginM TcPluginResult

data TcPluginM a

Instances

Monad TcPluginM

Methods

(>>=) :: TcPluginM a -> (a -> TcPluginM b) -> TcPluginM b

(>>) :: TcPluginM a -> TcPluginM b -> TcPluginM b

return :: a -> TcPluginM a

fail :: String -> TcPluginM a

Functor TcPluginM

Methods

fmap :: (a -> b) -> TcPluginM a -> TcPluginM b

(<$) :: a -> TcPluginM b -> TcPluginM a

MonadFail TcPluginM

Methods

fail :: String -> TcPluginM a

Applicative TcPluginM

Methods

pure :: a -> TcPluginM a

(<*>) :: TcPluginM (a -> b) -> TcPluginM a -> TcPluginM b

liftA2 :: (a -> b -> c) -> TcPluginM a -> TcPluginM b -> TcPluginM c

(*>) :: TcPluginM a -> TcPluginM b -> TcPluginM b

(<*) :: TcPluginM a -> TcPluginM b -> TcPluginM a

runTcPluginM :: TcPluginM a -> EvBindsVar -> TcM a

unsafeTcPluginTcM :: TcM a -> TcPluginM a

This function provides an escape for direct access to the TcM monad. It should not be used lightly, and the provided TcPluginM API should be favoured instead.

getEvBindsTcPluginM :: TcPluginM EvBindsVar

Access the EvBindsVar carried by the TcPluginM during constraint solving. Returns Nothing if invoked during tcPluginInit or tcPluginStop.

data CtFlavour

Constructors

Given

Wanted ShadowInfo

Derived

Instances

Eq CtFlavour

Methods

(==) :: CtFlavour -> CtFlavour -> Bool

(/=) :: CtFlavour -> CtFlavour -> Bool

Outputable CtFlavour

Methods

ppr :: CtFlavour -> SDoc

pprPrec :: Rational -> CtFlavour -> SDoc

data ShadowInfo

Constructors

WDeriv

WOnly

Instances

Eq ShadowInfo

Methods

(==) :: ShadowInfo -> ShadowInfo -> Bool

(/=) :: ShadowInfo -> ShadowInfo -> Bool

ctEvFlavour :: CtEvidence -> CtFlavour

type CtFlavourRole = (CtFlavour, EqRel)

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

ctEvFlavourRole :: CtEvidence -> CtFlavourRole

Extract the flavour, role, and boxity from a CtEvidence

ctFlavourRole :: Ct -> CtFlavourRole

Extract the flavour, role, and boxity from a Ct

eqCanRewriteFR :: CtFlavourRole -> CtFlavourRole -> Bool

eqMayRewriteFR :: CtFlavourRole -> CtFlavourRole -> Bool

eqCanDischarge :: CtEvidence -> CtEvidence -> Bool

funEqCanDischarge :: CtEvidence -> CtEvidence -> (SwapFlag, Bool)

funEqCanDischargeF :: CtFlavour -> CtFlavour -> (SwapFlag, Bool)

pprEvVarTheta :: [EvVar] -> SDoc

pprEvVars :: [EvVar] -> SDoc

pprEvVarWithType :: EvVar -> SDoc

type TcId = Id

type TcIdSet = IdSet

data Hole

An expression or type hole

Constructors

ExprHole UnboundVar

Either an out-of-scope variable or a "true" hole in an expression (TypedHoles)

TypeHole OccName

A hole in a type (PartialTypeSignatures)

holeOcc :: Hole -> OccName

data NameShape

A NameShape is a substitution on Names that can be used to refine the identities of a hole while we are renaming interfaces (see RnModIface). Specifically, a NameShape for ns_module_name A, defines a mapping from {A.T} (for some OccName T) to some arbitrary other Name.

The most intruiging thing about a NameShape, however, is how it's constructed. A NameShape is *implied* by the exported AvailInfos of the implementor of an interface: if an implementor of signature H exports M.T, you implicitly define a substitution from {H.T} to M.T. So a NameShape is computed from the list of AvailInfos that are exported by the implementation of a module, or successively merged together by the export lists of signatures which are joining together.

It's not the most obvious way to go about doing this, but it does seem to work!

NB: Can't boot this and put it in NameShape because then we start pulling in too many DynFlags things.

Constructors

NameShape

Fields

• ns_mod_name :: ModuleName
• ns_exports :: [AvailInfo]
• ns_map :: OccEnv Name