ghc-8.2.2: The GHC API

Safe Haskell | None
Language | Haskell2010

FamInstEnv

Contents

- CoAxioms

Synopsis

- data FamInst = FamInst {
  - fi_axiom :: CoAxiom Unbranched
  - fi_flavor :: FamFlavor
  - fi_fam :: Name
  - fi_tcs :: [Maybe Name]
  - fi_tvs :: [TyVar]
  - fi_cvs :: [CoVar]
  - fi_tys :: [Type]
  - fi_rhs :: Type
  }
- data FamFlavor
  - = SynFamilyInst
  - | DataFamilyInst TyCon
- famInstAxiom :: FamInst -> CoAxiom Unbranched
- famInstTyCon :: FamInst -> TyCon
- famInstRHS :: FamInst -> Type
- famInstsRepTyCons :: [FamInst] -> [TyCon]
- famInstRepTyCon_maybe :: FamInst -> Maybe TyCon
- dataFamInstRepTyCon :: FamInst -> TyCon
- pprFamInst :: FamInst -> SDoc
- pprFamInsts :: [FamInst] -> SDoc
- mkImportedFamInst :: Name -> [Maybe Name] -> CoAxiom Unbranched -> FamInst
- type FamInstEnvs = (FamInstEnv, FamInstEnv)
- type FamInstEnv = UniqDFM FamilyInstEnv
- emptyFamInstEnv :: FamInstEnv
- emptyFamInstEnvs :: (FamInstEnv, FamInstEnv)
- extendFamInstEnv :: FamInstEnv -> FamInst -> FamInstEnv
- extendFamInstEnvList :: FamInstEnv -> [FamInst] -> FamInstEnv
- famInstEnvElts :: FamInstEnv -> [FamInst]
- famInstEnvSize :: FamInstEnv -> Int
- familyInstances :: (FamInstEnv, FamInstEnv) -> TyCon -> [FamInst]
- mkCoAxBranch :: [TyVar] -> [CoVar] -> [Type] -> Type -> [Role] -> SrcSpan -> CoAxBranch
- mkBranchedCoAxiom :: Name -> TyCon -> [CoAxBranch] -> CoAxiom Branched
- mkUnbranchedCoAxiom :: Name -> TyCon -> CoAxBranch -> CoAxiom Unbranched
- mkSingleCoAxiom :: Role -> Name -> [TyVar] -> [CoVar] -> TyCon -> [Type] -> Type -> CoAxiom Unbranched
- mkNewTypeCoAxiom :: Name -> TyCon -> [TyVar] -> [Role] -> Type -> CoAxiom Unbranched
- data FamInstMatch = FamInstMatch {
  - fim_instance :: FamInst
  - fim_tys :: [Type]
  - fim_cos :: [Coercion]
  }
- lookupFamInstEnv :: FamInstEnvs -> TyCon -> [Type] -> [FamInstMatch]
- lookupFamInstEnvConflicts :: FamInstEnvs -> FamInst -> [FamInstMatch]
- lookupFamInstEnvByTyCon :: FamInstEnvs -> TyCon -> [FamInst]
- isDominatedBy :: CoAxBranch -> [CoAxBranch] -> Bool
- apartnessCheck :: [Type] -> CoAxBranch -> Bool
- data InjectivityCheckResult
  - = InjectivityAccepted
  - | InjectivityUnified CoAxBranch CoAxBranch
- lookupFamInstEnvInjectivityConflicts :: [Bool] -> FamInstEnvs -> FamInst -> [CoAxBranch]
- injectiveBranches :: [Bool] -> CoAxBranch -> CoAxBranch -> InjectivityCheckResult
- topNormaliseType :: FamInstEnvs -> Type -> Type
- topNormaliseType_maybe :: FamInstEnvs -> Type -> Maybe (Coercion, Type)
- normaliseType :: FamInstEnvs -> Role -> Type -> (Coercion, Type)
- normaliseTcApp :: FamInstEnvs -> Role -> TyCon -> [Type] -> (Coercion, Type)
- reduceTyFamApp_maybe :: FamInstEnvs -> Role -> TyCon -> [Type] -> Maybe (Coercion, Type)
- pmTopNormaliseType_maybe :: FamInstEnvs -> Type -> Maybe (Type, [DataCon], Type)
- flattenTys :: InScopeSet -> [Type] -> [Type]

# Documentation

data FamInst #

Constructors

FamInst |

Fields

- fi_axiom :: CoAxiom Unbranched
- fi_flavor :: FamFlavor
- fi_fam :: Name
- fi_tcs :: [Maybe Name]
- fi_tvs :: [TyVar]
- fi_cvs :: [CoVar]
- fi_tys :: [Type]
- fi_rhs :: Type

Instances

Outputable FamInst # |
Methods ppr :: FamInst -> SDoc # pprPrec :: Rational -> FamInst -> SDoc #
NamedThing FamInst # |
Methods getOccName :: FamInst -> OccName # getName :: FamInst -> Name #

data FamFlavor #

Constructors

SynFamilyInst |
DataFamilyInst TyCon |

famInstAxiom :: FamInst -> CoAxiom Unbranched #

famInstTyCon :: FamInst -> TyCon #

famInstRHS :: FamInst -> Type #

famInstsRepTyCons :: [FamInst] -> [TyCon] #

famInstRepTyCon_maybe :: FamInst -> Maybe TyCon #

dataFamInstRepTyCon :: FamInst -> TyCon #

pprFamInst :: FamInst -> SDoc #

pprFamInsts :: [FamInst] -> SDoc #

mkImportedFamInst :: Name -> [Maybe Name] -> CoAxiom Unbranched -> FamInst #

type FamInstEnvs = (FamInstEnv, FamInstEnv) #

type FamInstEnv = UniqDFM FamilyInstEnv #

emptyFamInstEnv :: FamInstEnv #

emptyFamInstEnvs :: (FamInstEnv, FamInstEnv) #

extendFamInstEnv :: FamInstEnv -> FamInst -> FamInstEnv #

extendFamInstEnvList :: FamInstEnv -> [FamInst] -> FamInstEnv #

famInstEnvElts :: FamInstEnv -> [FamInst] #

famInstEnvSize :: FamInstEnv -> Int #

familyInstances :: (FamInstEnv, FamInstEnv) -> TyCon -> [FamInst] #

# CoAxioms

mkCoAxBranch :: [TyVar] -> [CoVar] -> [Type] -> Type -> [Role] -> SrcSpan -> CoAxBranch #

mkBranchedCoAxiom :: Name -> TyCon -> [CoAxBranch] -> CoAxiom Branched #

mkUnbranchedCoAxiom :: Name -> TyCon -> CoAxBranch -> CoAxiom Unbranched #

mkSingleCoAxiom :: Role -> Name -> [TyVar] -> [CoVar] -> TyCon -> [Type] -> Type -> CoAxiom Unbranched #

mkNewTypeCoAxiom :: Name -> TyCon -> [TyVar] -> [Role] -> Type -> CoAxiom Unbranched #

Create a coercion constructor (axiom) suitable for the given newtype `TyCon`. The `Name` should be that of a new coercion `CoAxiom`, the `TyVar`s the arguments expected by the `newtype` and the type the appropriate right hand side of the `newtype`, with the free variables a subset of those `TyVar`s.

data FamInstMatch #

Constructors

FamInstMatch |

Fields

- fim_instance :: FamInst
- fim_tys :: [Type]
- fim_cos :: [Coercion]

Instances

Outputable FamInstMatch # |
Methods ppr :: FamInstMatch -> SDoc # pprPrec :: Rational -> FamInstMatch -> SDoc #

lookupFamInstEnv :: FamInstEnvs -> TyCon -> [Type] -> [FamInstMatch] #

lookupFamInstEnvConflicts :: FamInstEnvs -> FamInst -> [FamInstMatch] #

lookupFamInstEnvByTyCon :: FamInstEnvs -> TyCon -> [FamInst] #

isDominatedBy :: CoAxBranch -> [CoAxBranch] -> Bool #

apartnessCheck #

Arguments

:: [Type] | flattened target arguments. Make sure they're flattened! See Note [Flattening]. (NB: This "flat" is a different "flat" than is used in TcFlatten.)
-> CoAxBranch | the candidate equation we wish to use Precondition: this matches the target
-> Bool | True = equation can fire

Do an apartness check, as described in the "Closed Type Families" paper (POPL '14). This should be used when determining if an equation (`CoAxBranch`) of a closed type family can be used to reduce a certain target type family application.

data InjectivityCheckResult #

Result of testing two type family equations for injectiviy.

Constructors

InjectivityAccepted | Either RHSs are distinct or unification of RHSs leads to unification of LHSs
InjectivityUnified CoAxBranch CoAxBranch | RHSs unify but LHSs don't unify under that substitution. Relevant for closed type families where equation after unification might be overlpapped (in which case it is OK if they don't unify). Constructor stores axioms after unification.

lookupFamInstEnvInjectivityConflicts :: [Bool] -> FamInstEnvs -> FamInst -> [CoAxBranch] #

Check whether an open type family equation can be added to already existing instance environment without causing conflicts with supplied injectivity annotations. Returns list of conflicting axioms (type instance declarations).

injectiveBranches :: [Bool] -> CoAxBranch -> CoAxBranch -> InjectivityCheckResult #

Check whether two type family axioms don't violate injectivity annotation.

topNormaliseType :: FamInstEnvs -> Type -> Type #

topNormaliseType_maybe :: FamInstEnvs -> Type -> Maybe (Coercion, Type) #

Get rid of *outermost* (or toplevel) * type function redex * data family redex * newtypes returning an appropriate Representational coercion. Specifically, if topNormaliseType_maybe env ty = Just (co, ty') then (a) co :: ty ~R ty' (b) ty' is not a newtype, and is not a type-family or data-family redex

However, ty' can be something like (Maybe (F ty)), where (F ty) is a redex.

normaliseType :: FamInstEnvs -> Role -> Type -> (Coercion, Type) #

normaliseTcApp :: FamInstEnvs -> Role -> TyCon -> [Type] -> (Coercion, Type) #

reduceTyFamApp_maybe :: FamInstEnvs -> Role -> TyCon -> [Type] -> Maybe (Coercion, Type) #

pmTopNormaliseType_maybe :: FamInstEnvs -> Type -> Maybe (Type, [DataCon], Type) #

Get rid of *outermost* (or toplevel) * type function redex * data family redex * newtypes

Behaves exactly like `topNormaliseType_maybe`, but instead of returning a coercion, it returns useful information for issuing pattern matching warnings. See Note [Type normalisation for EmptyCase] for details.

flattenTys :: InScopeSet -> [Type] -> [Type] #