ghc-9.6.3: The GHC API
Safe HaskellSafe-Inferred
LanguageHaskell2010

GHC.Plugins

Description

This module is not used by GHC itself. Rather, it exports all of the functions and types you are likely to need when writing a plugin for GHC. So authors of plugins can probably get away simply with saying "import GHC.Plugins".

Particularly interesting modules for plugin writers include GHC.Core and GHC.Core.Opt.Monad.

Synopsis

Documentation

data OccName Source #

Occurrence Name

In this context that means: "classified (i.e. as a type name, value name, etc) but not qualified and not yet resolved"

Instances

Instances details
Data OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> OccName -> c OccName Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c OccName Source #

toConstr :: OccName -> Constr Source #

dataTypeOf :: OccName -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c OccName) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c OccName) Source #

gmapT :: (forall b. Data b => b -> b) -> OccName -> OccName Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> OccName -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> OccName -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> OccName -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> OccName -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> OccName -> m OccName Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> OccName -> m OccName Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> OccName -> m OccName Source #

NFData OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Methods

rnf :: OccName -> () Source #

HasOccName OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Uniquable OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Binary OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Outputable OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Methods

ppr :: OccName -> SDoc Source #

OutputableBndr OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Eq OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Methods

(==) :: OccName -> OccName -> Bool #

(/=) :: OccName -> OccName -> Bool #

Ord OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

type FastStringEnv a = UniqFM FastString a Source #

A non-deterministic set of FastStrings. See Note [Deterministic UniqFM] in GHC.Types.Unique.DFM for explanation why it's not deterministic and why it matters. Use DFastStringEnv if the set eventually gets converted into a list or folded over in a way where the order changes the generated code.

class HasOccName name where Source #

Other names in the compiler add additional information to an OccName. This class provides a consistent way to access the underlying OccName.

Methods

occName :: name -> OccName Source #

Instances

Instances details
HasOccName IfaceClassOp Source # 
Instance details

Defined in GHC.Iface.Syntax

HasOccName IfaceConDecl Source # 
Instance details

Defined in GHC.Iface.Syntax

HasOccName IfaceDecl Source # 
Instance details

Defined in GHC.Iface.Syntax

HasOccName HoleFitCandidate Source # 
Instance details

Defined in GHC.Tc.Errors.Hole.FitTypes

HasOccName TcBinder Source # 
Instance details

Defined in GHC.Tc.Types

HasOccName GreName Source # 
Instance details

Defined in GHC.Types.Avail

HasOccName FieldLabel Source # 
Instance details

Defined in GHC.Types.FieldLabel

HasOccName Name Source # 
Instance details

Defined in GHC.Types.Name

Methods

occName :: Name -> OccName Source #

HasOccName OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

HasOccName GlobalRdrElt Source # 
Instance details

Defined in GHC.Types.Name.Reader

HasOccName RdrName Source # 
Instance details

Defined in GHC.Types.Name.Reader

HasOccName Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

occName :: Var -> OccName Source #

(HasOccName (IdP (GhcPass p)), OutputableBndrId p) => HasOccName (IEWrappedName (GhcPass p)) Source # 
Instance details

Defined in GHC.Hs.ImpExp

data OccEnv a Source #

Instances

Instances details
Data a => Data (OccEnv a) Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> OccEnv a -> c (OccEnv a) Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (OccEnv a) Source #

toConstr :: OccEnv a -> Constr Source #

dataTypeOf :: OccEnv a -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (OccEnv a)) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (OccEnv a)) Source #

gmapT :: (forall b. Data b => b -> b) -> OccEnv a -> OccEnv a Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> OccEnv a -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> OccEnv a -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> OccEnv a -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> OccEnv a -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> OccEnv a -> m (OccEnv a) Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> OccEnv a -> m (OccEnv a) Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> OccEnv a -> m (OccEnv a) Source #

Outputable a => Outputable (OccEnv a) Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Methods

ppr :: OccEnv a -> SDoc Source #

isSymOcc :: OccName -> Bool Source #

Test if the OccName is that for any operator (whether it is a data constructor or variable or whatever)

pprOccName :: IsLine doc => OccName -> doc Source #

mkDFunOcc Source #

Arguments

:: String

Typically the class and type glommed together e.g. OrdMaybe. Only used in debug mode, for extra clarity

-> Bool

Is this a hs-boot instance DFun?

-> OccSet

avoid these Occs

-> OccName

E.g. $f3OrdMaybe

isDerivedOccName :: OccName -> Bool Source #

Test for definitions internally generated by GHC. This predicate is used to suppress printing of internal definitions in some debug prints

isTypeableBindOcc :: OccName -> Bool Source #

Is an OccName one of a Typeable TyCon or Module binding? This is needed as these bindings are renamed differently. See Note [Grand plan for Typeable] in GHC.Tc.Instance.Typeable.

mkSuperDictSelOcc Source #

Arguments

:: Int

Index of superclass, e.g. 3

-> OccName

Class, e.g. Ord

-> OccName

Derived Occname, e.g. $p3Ord

mkLocalOcc Source #

Arguments

:: Unique

Unique to combine with the OccName

-> OccName

Local name, e.g. sat

-> OccName

Nice unique version, e.g. $L23sat

mkInstTyTcOcc Source #

Arguments

:: String

Family name, e.g. Map

-> OccSet

avoid these Occs

-> OccName
R:Map

Derive a name for the representation type constructor of a data/newtype instance.

isDataSymOcc :: OccName -> Bool Source #

Test if the OccName is a data constructor that starts with a symbol (e.g. :, or [])

isValOcc :: OccName -> Bool Source #

Value OccNamess are those that are either in the variable or data constructor namespaces

parenSymOcc :: OccName -> SDoc -> SDoc Source #

Wrap parens around an operator

startsWithUnderscore :: OccName -> Bool Source #

Haskell 98 encourages compilers to suppress warnings about unused names in a pattern if they start with _: this implements that test

mapOccEnv :: (a -> b) -> OccEnv a -> OccEnv b Source #

mkOccEnv :: [(OccName, a)] -> OccEnv a Source #

mkOccEnv_C :: (a -> a -> a) -> [(OccName, a)] -> OccEnv a Source #

foldOccEnv :: (a -> b -> b) -> b -> OccEnv a -> b Source #

plusOccEnv_C :: (a -> a -> a) -> OccEnv a -> OccEnv a -> OccEnv a Source #

extendOccEnv_C :: (a -> a -> a) -> OccEnv a -> OccName -> a -> OccEnv a Source #

extendOccEnv_Acc :: (a -> b -> b) -> (a -> b) -> OccEnv b -> OccName -> a -> OccEnv b Source #

filterOccEnv :: (elt -> Bool) -> OccEnv elt -> OccEnv elt Source #

alterOccEnv :: (Maybe elt -> Maybe elt) -> OccEnv elt -> OccName -> OccEnv elt Source #

minusOccEnv_C :: (a -> b -> Maybe a) -> OccEnv a -> OccEnv b -> OccEnv a Source #

Alters (replaces or removes) those elements of the map that are mentioned in the second map

pprOccEnv :: (a -> SDoc) -> OccEnv a -> SDoc Source #

occSetToEnv :: OccSet -> OccEnv OccName Source #

Converts an OccSet to an OccEnv (operationally the identity)

data Name Source #

A unique, unambiguous name for something, containing information about where that thing originated.

Instances

Instances details
Data Name Source # 
Instance details

Defined in GHC.Types.Name

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Name -> c Name Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Name Source #

toConstr :: Name -> Constr Source #

dataTypeOf :: Name -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Name) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Name) Source #

gmapT :: (forall b. Data b => b -> b) -> Name -> Name Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Name -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Name -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Name -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Name -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Name -> m Name Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Name -> m Name Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Name -> m Name Source #

NFData Name Source # 
Instance details

Defined in GHC.Types.Name

Methods

rnf :: Name -> () Source #

NamedThing Name Source # 
Instance details

Defined in GHC.Types.Name

HasOccName Name Source # 
Instance details

Defined in GHC.Types.Name

Methods

occName :: Name -> OccName Source #

Uniquable Name Source # 
Instance details

Defined in GHC.Types.Name

Binary Name Source #

Assumes that the Name is a non-binding one. See putIfaceTopBndr and getIfaceTopBndr for serializing binding Names. See UserData for the rationale for this distinction.

Instance details

Defined in GHC.Types.Name

Outputable Name Source # 
Instance details

Defined in GHC.Types.Name

Methods

ppr :: Name -> SDoc Source #

OutputableBndr Name Source # 
Instance details

Defined in GHC.Types.Name

Eq Name Source #

The same comments as for Name's Ord instance apply.

Instance details

Defined in GHC.Types.Name

Methods

(==) :: Name -> Name -> Bool #

(/=) :: Name -> Name -> Bool #

Ord Name Source #

Caution: This instance is implemented via nonDetCmpUnique, which means that the ordering is not stable across deserialization or rebuilds.

See nonDetCmpUnique for further information, and trac #15240 for a bug caused by improper use of this instance.

Instance details

Defined in GHC.Types.Name

Methods

compare :: Name -> Name -> Ordering #

(<) :: Name -> Name -> Bool #

(<=) :: Name -> Name -> Bool #

(>) :: Name -> Name -> Bool #

(>=) :: Name -> Name -> Bool #

max :: Name -> Name -> Name #

min :: Name -> Name -> Name #

type Anno Name Source # 
Instance details

Defined in GHC.Hs.Extension

type Anno (LocatedN Name) Source # 
Instance details

Defined in GHC.Hs.Binds

type Anno [LocatedN Name] Source # 
Instance details

Defined in GHC.Hs.Binds

data OccName Source #

Occurrence Name

In this context that means: "classified (i.e. as a type name, value name, etc) but not qualified and not yet resolved"

Instances

Instances details
Data OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> OccName -> c OccName Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c OccName Source #

toConstr :: OccName -> Constr Source #

dataTypeOf :: OccName -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c OccName) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c OccName) Source #

gmapT :: (forall b. Data b => b -> b) -> OccName -> OccName Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> OccName -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> OccName -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> OccName -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> OccName -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> OccName -> m OccName Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> OccName -> m OccName Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> OccName -> m OccName Source #

NFData OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Methods

rnf :: OccName -> () Source #

HasOccName OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Uniquable OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Binary OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Outputable OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Methods

ppr :: OccName -> SDoc Source #

OutputableBndr OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Eq OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Methods

(==) :: OccName -> OccName -> Bool #

(/=) :: OccName -> OccName -> Bool #

Ord OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

class NamedThing a where Source #

A class allowing convenient access to the Name of various datatypes

Minimal complete definition

getName

Methods

getOccName :: a -> OccName Source #

getName :: a -> Name Source #

Instances

Instances details
NamedThing Class Source # 
Instance details

Defined in GHC.Core.Class

NamedThing ConLike Source # 
Instance details

Defined in GHC.Core.ConLike

NamedThing DataCon Source # 
Instance details

Defined in GHC.Core.DataCon

NamedThing FamInst Source # 
Instance details

Defined in GHC.Core.FamInstEnv

NamedThing ClsInst Source # 
Instance details

Defined in GHC.Core.InstEnv

NamedThing PatSyn Source # 
Instance details

Defined in GHC.Core.PatSyn

NamedThing TyCon Source # 
Instance details

Defined in GHC.Core.TyCon

NamedThing IfaceClassOp Source # 
Instance details

Defined in GHC.Iface.Syntax

NamedThing IfaceConDecl Source # 
Instance details

Defined in GHC.Iface.Syntax

NamedThing IfaceDecl Source # 
Instance details

Defined in GHC.Iface.Syntax

NamedThing HoleFitCandidate Source # 
Instance details

Defined in GHC.Tc.Errors.Hole.FitTypes

NamedThing Name Source # 
Instance details

Defined in GHC.Types.Name

NamedThing TyThing Source # 
Instance details

Defined in GHC.Types.TyThing

NamedThing Var Source # 
Instance details

Defined in GHC.Types.Var

NamedThing (CoAxiom br) Source # 
Instance details

Defined in GHC.Core.Coercion.Axiom

NamedThing e => NamedThing (Located e) Source # 
Instance details

Defined in GHC.Types.Name

NamedThing (Located a) => NamedThing (LocatedAn an a) Source # 
Instance details

Defined in GHC.Parser.Annotation

NamedThing tv => NamedThing (VarBndr tv flag) Source # 
Instance details

Defined in GHC.Types.Var

Methods

getOccName :: VarBndr tv flag -> OccName Source #

getName :: VarBndr tv flag -> Name Source #

NamedThing (HsTyVarBndr flag GhcRn) Source # 
Instance details

Defined in GHC.Hs.Type

data BuiltInSyntax Source #

BuiltInSyntax is for things like (:), [] and tuples, which have special syntactic forms. They aren't in scope as such.

Constructors

BuiltInSyntax 
UserSyntax 

type FastStringEnv a = UniqFM FastString a Source #

A non-deterministic set of FastStrings. See Note [Deterministic UniqFM] in GHC.Types.Unique.DFM for explanation why it's not deterministic and why it matters. Use DFastStringEnv if the set eventually gets converted into a list or folded over in a way where the order changes the generated code.

class HasOccName name where Source #

Other names in the compiler add additional information to an OccName. This class provides a consistent way to access the underlying OccName.

Methods

occName :: name -> OccName Source #

Instances

Instances details
HasOccName IfaceClassOp Source # 
Instance details

Defined in GHC.Iface.Syntax

HasOccName IfaceConDecl Source # 
Instance details

Defined in GHC.Iface.Syntax

HasOccName IfaceDecl Source # 
Instance details

Defined in GHC.Iface.Syntax

HasOccName HoleFitCandidate Source # 
Instance details

Defined in GHC.Tc.Errors.Hole.FitTypes

HasOccName TcBinder Source # 
Instance details

Defined in GHC.Tc.Types

HasOccName GreName Source # 
Instance details

Defined in GHC.Types.Avail

HasOccName FieldLabel Source # 
Instance details

Defined in GHC.Types.FieldLabel

HasOccName Name Source # 
Instance details

Defined in GHC.Types.Name

Methods

occName :: Name -> OccName Source #

HasOccName OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

HasOccName GlobalRdrElt Source # 
Instance details

Defined in GHC.Types.Name.Reader

HasOccName RdrName Source # 
Instance details

Defined in GHC.Types.Name.Reader

HasOccName Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

occName :: Var -> OccName Source #

(HasOccName (IdP (GhcPass p)), OutputableBndrId p) => HasOccName (IEWrappedName (GhcPass p)) Source # 
Instance details

Defined in GHC.Hs.ImpExp

data OccEnv a Source #

Instances

Instances details
Data a => Data (OccEnv a) Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> OccEnv a -> c (OccEnv a) Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (OccEnv a) Source #

toConstr :: OccEnv a -> Constr Source #

dataTypeOf :: OccEnv a -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (OccEnv a)) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (OccEnv a)) Source #

gmapT :: (forall b. Data b => b -> b) -> OccEnv a -> OccEnv a Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> OccEnv a -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> OccEnv a -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> OccEnv a -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> OccEnv a -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> OccEnv a -> m (OccEnv a) Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> OccEnv a -> m (OccEnv a) Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> OccEnv a -> m (OccEnv a) Source #

Outputable a => Outputable (OccEnv a) Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Methods

ppr :: OccEnv a -> SDoc Source #

pprName :: forall doc. IsLine doc => Name -> doc Source #

isSymOcc :: OccName -> Bool Source #

Test if the OccName is that for any operator (whether it is a data constructor or variable or whatever)

nameIsLocalOrFrom :: Module -> Name -> Bool Source #

Returns True if the name is (a) Internal (b) External but from the specified module (c) External but from the interactive package

The key idea is that False means: the entity is defined in some other module you can find the details (type, fixity, instances) in some interface file those details will be stored in the EPT or HPT

True means: the entity is defined in this module or earlier in the GHCi session you can find details (type, fixity, instances) in the TcGblEnv or TcLclEnv

The isInteractiveModule part is because successive interactions of a GHCi session each give rise to a fresh module (Ghci1, Ghci2, etc), but they all come from the magic interactive package; and all the details are kept in the TcLclEnv, TcGblEnv, NOT in the HPT or EPT. See Note [The interactive package] in GHC.Runtime.Context

isDynLinkName :: Platform -> Module -> Name -> Bool Source #

Will the Name come from a dynamically linked package?

mkSystemName :: Unique -> OccName -> Name Source #

Create a name brought into being by the compiler

mkInternalName :: Unique -> OccName -> SrcSpan -> Name Source #

Create a name which is (for now at least) local to the current module and hence does not need a GenModule to disambiguate it from other Names

mkFCallName :: Unique -> FastString -> Name Source #

Make a name for a foreign call

mkExternalName :: Unique -> Module -> OccName -> SrcSpan -> Name Source #

Create a name which definitely originates in the given module

mkWiredInName :: Module -> OccName -> Unique -> TyThing -> BuiltInSyntax -> Name Source #

Create a name which is actually defined by the compiler itself

localiseName :: Name -> Name Source #

Make the Name into an internal name, regardless of what it was to begin with

pprFullName :: Module -> Name -> SDoc Source #

Print fully qualified name (with unit-id, module and unique)

pprTickyName :: Module -> Name -> SDoc Source #

Print a ticky ticky styled name

Module argument is the module to use for internal and system names. When printing the name in a ticky profile, the module name is included even for local things. However, ticky uses the format "x (M)" rather than "M.x". Hence, this function provides a separation from normal styling.

isWiredIn :: NamedThing thing => thing -> Bool Source #

nameIsExternalOrFrom :: Module -> Name -> Bool Source #

Returns True if the name is external or from the interactive package See documentation of nameIsLocalOrFrom function

nameIsFromExternalPackage :: HomeUnit -> Name -> Bool Source #

Returns True if the Name comes from some other package: neither this package nor the interactive package.

stableNameCmp :: Name -> Name -> Ordering Source #

Compare Names lexicographically This only works for Names that originate in the source code or have been tidied.

pprNameUnqualified :: Name -> SDoc Source #

Print the string of Name unqualifiedly directly.

nameStableString :: Name -> String Source #

Get a string representation of a Name that's unique and stable across recompilations. Used for deterministic generation of binds for derived instances. eg. "$aeson_70dylHtv1FFGeai1IoxcQr$Data.Aeson.Types.Internal$String"

pprOccName :: IsLine doc => OccName -> doc Source #

mkDFunOcc Source #

Arguments

:: String

Typically the class and type glommed together e.g. OrdMaybe. Only used in debug mode, for extra clarity

-> Bool

Is this a hs-boot instance DFun?

-> OccSet

avoid these Occs

-> OccName

E.g. $f3OrdMaybe

isDerivedOccName :: OccName -> Bool Source #

Test for definitions internally generated by GHC. This predicate is used to suppress printing of internal definitions in some debug prints

isTypeableBindOcc :: OccName -> Bool Source #

Is an OccName one of a Typeable TyCon or Module binding? This is needed as these bindings are renamed differently. See Note [Grand plan for Typeable] in GHC.Tc.Instance.Typeable.

mkSuperDictSelOcc Source #

Arguments

:: Int

Index of superclass, e.g. 3

-> OccName

Class, e.g. Ord

-> OccName

Derived Occname, e.g. $p3Ord

mkLocalOcc Source #

Arguments

:: Unique

Unique to combine with the OccName

-> OccName

Local name, e.g. sat

-> OccName

Nice unique version, e.g. $L23sat

mkInstTyTcOcc Source #

Arguments

:: String

Family name, e.g. Map

-> OccSet

avoid these Occs

-> OccName
R:Map

Derive a name for the representation type constructor of a data/newtype instance.

isDataSymOcc :: OccName -> Bool Source #

Test if the OccName is a data constructor that starts with a symbol (e.g. :, or [])

isValOcc :: OccName -> Bool Source #

Value OccNamess are those that are either in the variable or data constructor namespaces

parenSymOcc :: OccName -> SDoc -> SDoc Source #

Wrap parens around an operator

startsWithUnderscore :: OccName -> Bool Source #

Haskell 98 encourages compilers to suppress warnings about unused names in a pattern if they start with _: this implements that test

mapOccEnv :: (a -> b) -> OccEnv a -> OccEnv b Source #

mkOccEnv :: [(OccName, a)] -> OccEnv a Source #

mkOccEnv_C :: (a -> a -> a) -> [(OccName, a)] -> OccEnv a Source #

foldOccEnv :: (a -> b -> b) -> b -> OccEnv a -> b Source #

plusOccEnv_C :: (a -> a -> a) -> OccEnv a -> OccEnv a -> OccEnv a Source #

extendOccEnv_C :: (a -> a -> a) -> OccEnv a -> OccName -> a -> OccEnv a Source #

extendOccEnv_Acc :: (a -> b -> b) -> (a -> b) -> OccEnv b -> OccName -> a -> OccEnv b Source #

filterOccEnv :: (elt -> Bool) -> OccEnv elt -> OccEnv elt Source #

alterOccEnv :: (Maybe elt -> Maybe elt) -> OccEnv elt -> OccName -> OccEnv elt Source #

minusOccEnv_C :: (a -> b -> Maybe a) -> OccEnv a -> OccEnv b -> OccEnv a Source #

Alters (replaces or removes) those elements of the map that are mentioned in the second map

pprOccEnv :: (a -> SDoc) -> OccEnv a -> SDoc Source #

occSetToEnv :: OccSet -> OccEnv OccName Source #

Converts an OccSet to an OccEnv (operationally the identity)

type Id = Var Source #

Identifier

data Var Source #

Variable

Essentially a typed Name, that may also contain some additional information about the Var and its use sites.

Instances

Instances details
Data Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Var -> c Var Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Var Source #

toConstr :: Var -> Constr Source #

dataTypeOf :: Var -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Var) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Var) Source #

gmapT :: (forall b. Data b => b -> b) -> Var -> Var Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Var -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Var -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Var -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Var -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Var -> m Var Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Var -> m Var Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Var -> m Var Source #

NamedThing Var Source # 
Instance details

Defined in GHC.Types.Var

HasOccName Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

occName :: Var -> OccName Source #

Uniquable Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

getUnique :: Var -> Unique Source #

Outputable Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

ppr :: Var -> SDoc Source #

OutputableBndr Var Source # 
Instance details

Defined in GHC.Core.Ppr

Eq Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

(==) :: Var -> Var -> Bool #

(/=) :: Var -> Var -> Bool #

Ord Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

compare :: Var -> Var -> Ordering #

(<) :: Var -> Var -> Bool #

(<=) :: Var -> Var -> Bool #

(>) :: Var -> Var -> Bool #

(>=) :: Var -> Var -> Bool #

max :: Var -> Var -> Var #

min :: Var -> Var -> Var #

Eq (DeBruijn CoreAlt) Source # 
Instance details

Defined in GHC.Core.Map.Expr

Eq (DeBruijn CoreExpr) Source # 
Instance details

Defined in GHC.Core.Map.Expr

Eq (DeBruijn Var) Source # 
Instance details

Defined in GHC.Core.Map.Type

OutputableBndr (Id, TagSig) Source # 
Instance details

Defined in GHC.Stg.InferTags.TagSig

type Anno Id Source # 
Instance details

Defined in GHC.Hs.Extension

type Anno (LocatedN Id) Source # 
Instance details

Defined in GHC.Hs.Binds

type Anno [LocatedN Id] Source # 
Instance details

Defined in GHC.Hs.Binds

type InId = Id Source #

type InVar = Var Source #

type OutId = Id Source #

type JoinId = Id Source #

isImplicitId :: Id -> Bool Source #

isImplicitId tells whether an Ids info is implied by other declarations, so we don't need to put its signature in an interface file, even if it's mentioned in some other interface unfolding.

isExportedId :: Var -> Bool Source #

isExportedIdVar means "don't throw this away"

idDataCon :: Id -> DataCon Source #

Get from either the worker or the wrapper Id to the DataCon. Currently used only in the desugarer.

INVARIANT: idDataCon (dataConWrapId d) = d: remember, dataConWrapId can return either the wrapper or the worker

isDeadEndId :: Var -> Bool Source #

Returns true if an application to n args diverges or throws an exception See Note [Dead ends] in GHC.Types.Demand.

recordSelectorTyCon :: Id -> RecSelParent Source #

If the Id is that for a record selector, extract the sel_tycon. Panic otherwise.

isId :: Var -> Bool Source #

Is this a value-level (i.e., computationally relevant) Varentifier? Satisfies isId = not . isTyVar.

isJoinId_maybe :: Var -> Maybe JoinArity Source #

Doesn't return strictness marks

idUnfolding :: IdUnfoldingFun Source #

Returns the Ids unfolding, but does not expose the unfolding of a strong loop breaker. See unfoldingInfo.

If you really want the unfolding of a strong loopbreaker, call realIdUnfolding.

mkLocalId :: HasDebugCallStack => Name -> Mult -> Type -> Id Source #

For an explanation of global vs. local Ids, see GHC.Types.Var

realIdUnfolding :: Id -> Unfolding Source #

Expose the unfolding if there is one, including for loop breakers

mkTemplateLocals :: [Type] -> [Id] Source #

Create a template local for a series of types

mkGlobalId :: IdDetails -> Name -> Type -> IdInfo -> Id Source #

For an explanation of global vs. local Ids, see GHC.Types.Var.Var

mkVanillaGlobal :: Name -> Type -> Id Source #

Make a global Id without any extra information at all

mkVanillaGlobalWithInfo :: Name -> Type -> IdInfo -> Id Source #

Make a global Id with no global information but some generic IdInfo

mkLocalCoVar :: Name -> Type -> CoVar Source #

Make a local CoVar

mkLocalIdOrCoVar :: Name -> Mult -> Type -> Id Source #

Like mkLocalId, but checks the type to see if it should make a covar

mkExportedLocalId :: IdDetails -> Name -> Type -> Id Source #

Create a local Id that is marked as exported. This prevents things attached to it from being removed as dead code. See Note [Exported LocalIds]

mkSysLocal :: FastString -> Unique -> Mult -> Type -> Id Source #

Create a system local Id. These are local Ids (see Var) that are created by the compiler out of thin air

mkSysLocalOrCoVar :: FastString -> Unique -> Mult -> Type -> Id Source #

Like mkSysLocal, but checks to see if we have a covar type

mkUserLocal :: OccName -> Unique -> Mult -> Type -> SrcSpan -> Id Source #

Create a user local Id. These are local Ids (see GHC.Types.Var) with a name and location that the user might recognize

mkUserLocalOrCoVar :: OccName -> Unique -> Mult -> Type -> SrcSpan -> Id Source #

Like mkUserLocal, but checks if we have a coercion type

mkTemplateLocalsNum :: Int -> [Type] -> [Id] Source #

Create a template local for a series of type, but start from a specified template local

mkTemplateLocal :: Int -> Type -> Id Source #

Create a template local: a family of system local Ids in bijection with Ints, typically used in unfoldings

mkWorkerId :: Unique -> Id -> Type -> Id Source #

Workers get local names. CoreTidy will externalise these if necessary

updateIdTypeAndMultM :: Monad m => (Type -> m Type) -> Id -> m Id Source #

globaliseId :: Id -> Id Source #

If it's a local, make it global

scaleVarBy :: Mult -> Var -> Var Source #

Like scaleIdBy, but skips non-Ids. Useful for scaling a mixed list of ids and tyvars.

isStrictId :: Id -> Bool Source #

isStrictId says whether either (a) the Id has a strict demand placed on it or (b) definitely has a "strict type", such that it can always be evaluated strictly (i.e an unlifted type) We need to check (b) as well as (a), because when the demand for the given id hasn't been computed yet but id has a strict type, we still want `isStrictId id` to be True. Returns False if the type is levity polymorphic; False is always safe.

isWorkerLikeId :: Id -> Bool Source #

An Id for which we might require all callers to pass strict arguments properly tagged + evaluated.

See Note [CBV Function Ids]

hasNoBinding :: Id -> Bool Source #

Returns True of an Id which may not have a binding, even though it is defined in this module.

asJoinId :: Id -> JoinArity -> JoinId infixl 1 Source #

idFunRepArity :: Id -> RepArity Source #

This function counts all arguments post-unarisation, which includes arguments with no runtime representation -- see Note [Unarisation and arity]

idCafInfo :: Id -> CafInfo infixl 1 Source #

alwaysActiveUnfoldingFun :: IdUnfoldingFun Source #

Returns an unfolding only if (a) not a strong loop breaker and (b) always active

whenActiveUnfoldingFun :: (Activation -> Bool) -> IdUnfoldingFun Source #

Returns an unfolding only if (a) not a strong loop breaker and (b) active in according to is_active

setIdUnfolding :: Id -> Unfolding -> Id infixl 1 Source #

zapIdUnfolding :: Id -> Id Source #

Similar to trimUnfolding, but also removes evaldness info.

setIdArity :: Id -> Arity -> Id infixl 1 Source #

setIdCallArity :: Id -> Arity -> Id infixl 1 Source #

setIdOccInfo :: Id -> OccInfo -> Id infixl 1 Source #

setIdDemandInfo :: Id -> Demand -> Id infixl 1 Source #

setIdDmdSig :: Id -> DmdSig -> Id infixl 1 Source #

setIdCprSig :: Id -> CprSig -> Id infixl 1 Source #

setIdCbvMarks :: Id -> [CbvMark] -> Id infixl 1 Source #

If all marks are NotMarkedStrict we just set nothing.

asWorkerLikeId :: Id -> Id Source #

Turn this id into a WorkerLikeId if possible.

asNonWorkerLikeId :: Id -> Id Source #

Remove any cbv marks on arguments from a given Id.

idDmdSig :: Id -> DmdSig Source #

Accesses the Id's dmdSigInfo.

setIdType :: Id -> Type -> Id Source #

Not only does this set the Id Type, it also evaluates the type to try and reduce space usage

module GHC.Core

data InScopeSet Source #

A set of variables that are in scope at some point.

Note that this is a superset of the variables that are currently in scope. See Note [The InScopeSet invariant].

"Secrets of the Glasgow Haskell Compiler inliner" Section 3.2 provides the motivation for this abstraction.

Instances

Instances details
Outputable InScopeSet Source # 
Instance details

Defined in GHC.Types.Var.Env

Methods

ppr :: InScopeSet -> SDoc Source #

data Subst Source #

Type & coercion & id substitution

The Subst data type defined in this module contains substitution for tyvar, covar and id. However, operations on IdSubstEnv (mapping from Id to CoreExpr) that require the definition of the Expr data type are defined in GHC.Core.Subst to avoid circular module dependency.

Instances

Instances details
Outputable Subst Source # 
Instance details

Defined in GHC.Core.TyCo.Subst

Methods

ppr :: Subst -> SDoc Source #

type TvSubstEnv = TyVarEnv Type Source #

A substitution of Types for TyVars and Kinds for KindVars

type IdSubstEnv = IdEnv CoreExpr Source #

A substitution of Exprs for non-coercion Ids

substCo :: HasDebugCallStack => Subst -> Coercion -> Coercion Source #

Substitute within a Coercion The substitution has to satisfy the invariants described in Note [The substitution invariant].

extendIdSubst :: Subst -> Id -> CoreExpr -> Subst Source #

Add a substitution for an Id to the Subst: you must ensure that the in-scope set is such that TyCoSubst Note [The substitution invariant] holds after extending the substitution like this

extendTvSubst :: Subst -> TyVar -> Type -> Subst Source #

Add a substitution for a TyVar to the Subst The TyVar *must* be a real TyVar, and not a CoVar You must ensure that the in-scope set is such that Note [The substitution invariant] holds after extending the substitution like this.

zapSubst :: Subst -> Subst Source #

Remove all substitutions that might have been built up while preserving the in-scope set originally called zapSubstEnv

extendTvSubstList :: Subst -> [(TyVar, Type)] -> Subst Source #

Adds multiple TyVar substitutions to the Subst: see also extendTvSubst

deShadowBinds :: CoreProgram -> CoreProgram Source #

De-shadowing the program is sometimes a useful pre-pass. It can be done simply by running over the bindings with an empty substitution, because substitution returns a result that has no-shadowing guaranteed.

(Actually, within a single type there might still be shadowing, because substTy is a no-op for the empty substitution, but that's probably OK.)

Aug 09
This function is not used in GHC at the moment, but seems so short and simple that I'm going to leave it here

substRuleInfo :: Subst -> Id -> RuleInfo -> RuleInfo Source #

Substitutes for the Ids within the RuleInfo given the new function Id

substTyUnchecked :: Subst -> Type -> Type Source #

Substitute within a Type disabling the sanity checks. The problems that the sanity checks in substTy catch are described in Note [The substitution invariant]. The goal of #11371 is to migrate all the calls of substTyUnchecked to substTy and remove this function. Please don't use in new code.

substExpr :: HasDebugCallStack => Subst -> CoreExpr -> CoreExpr Source #

substExpr applies a substitution to an entire CoreExpr. Remember, you may only apply the substitution once: See Note [Substitutions apply only once] in GHC.Core.TyCo.Subst

Do *not* attempt to short-cut in the case of an empty substitution! See Note [Extending the IdSubstEnv]

substBind :: HasDebugCallStack => Subst -> CoreBind -> (Subst, CoreBind) Source #

Apply a substitution to an entire CoreBind, additionally returning an updated Subst that should be used by subsequent substitutions.

substBindSC :: HasDebugCallStack => Subst -> CoreBind -> (Subst, CoreBind) Source #

Apply a substitution to an entire CoreBind, additionally returning an updated Subst that should be used by subsequent substitutions.

substUnfolding :: Subst -> Unfolding -> Unfolding Source #

Substitutes for the Ids within an unfolding NB: substUnfolding discards any unfolding without without a Stable source. This is usually what we want, but it may be a bit unexpected

substUnfoldingSC :: Subst -> Unfolding -> Unfolding Source #

Substitutes for the Ids within an unfolding NB: substUnfolding discards any unfolding without without a Stable source. This is usually what we want, but it may be a bit unexpected

lookupIdSubst :: HasDebugCallStack => Subst -> Id -> CoreExpr Source #

Find the substitution for an Id in the Subst The Id should not be a CoVar

substIdInfo :: Subst -> Id -> IdInfo -> Maybe IdInfo Source #

Substitute into some IdInfo with regard to the supplied new Id. Discards unfoldings, unless they are Stable

mkOpenSubst :: InScopeSet -> [(Var, CoreArg)] -> Subst Source #

Simultaneously substitute for a bunch of variables No left-right shadowing ie the substitution for (x y. e) a1 a2 so neither x nor y scope over a1 a2

extendIdSubstList :: Subst -> [(Id, CoreExpr)] -> Subst Source #

Adds multiple Id substitutions to the Subst: see also extendIdSubst

extendSubst :: Subst -> Var -> CoreArg -> Subst Source #

Add a substitution appropriate to the thing being substituted (whether an expression, type, or coercion). See also extendIdSubst, extendTvSubst, extendCvSubst

extendSubstList :: Subst -> [(Var, CoreArg)] -> Subst Source #

Add a substitution as appropriate to each of the terms being substituted (whether expressions, types, or coercions). See also extendSubst.

extendSubstInScope :: Subst -> Var -> Subst Source #

Add the Var to the in-scope set

extendSubstInScopeList :: Subst -> [Var] -> Subst Source #

Add the Vars to the in-scope set: see also extendInScope

getSubstInScope :: Subst -> InScopeSet Source #

Find the in-scope set: see Note [The substitution invariant]

substBndr :: Subst -> Var -> (Subst, Var) Source #

Substitutes a Expr for another one according to the Subst given, returning the result and an updated Subst that should be used by subsequent substitutions. IdInfo is preserved by this process, although it is substituted into appropriately.

substBndrs :: Traversable f => Subst -> f Var -> (Subst, f Var) Source #

Applies substBndr to a number of Exprs, accumulating a new Subst left-to-right

substRecBndrs :: Traversable f => Subst -> f Id -> (Subst, f Id) Source #

Substitute in a mutually recursive group of Ids

cloneIdBndr :: Subst -> UniqSupply -> Id -> (Subst, Id) Source #

Very similar to substBndr, but it always allocates a new Unique for each variable in its output. It substitutes the IdInfo though. Discards non-Stable unfoldings

cloneIdBndrs :: Subst -> UniqSupply -> [Id] -> (Subst, [Id]) Source #

Applies cloneIdBndr to a number of Ids, accumulating a final substitution from left to right Discards non-Stable unfoldings

cloneRecIdBndrs :: Subst -> UniqSupply -> [Id] -> (Subst, [Id]) Source #

Clone a mutually recursive group of Ids

data Type Source #

Instances

Instances details
Data Type Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Type -> c Type Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Type Source #

toConstr :: Type -> Constr Source #

dataTypeOf :: Type -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Type) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Type) Source #

gmapT :: (forall b. Data b => b -> b) -> Type -> Type Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Type -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Type -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Type -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Type -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Type -> m Type Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Type -> m Type Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Type -> m Type Source #

Outputable Type Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Methods

ppr :: Type -> SDoc Source #

Eq (DeBruijn Type) Source # 
Instance details

Defined in GHC.Core.Map.Type

type Kind = Type Source #

The key type representing kinds in the compiler.

data Specificity Source #

Whether an Invisible argument may appear in source Haskell.

Constructors

InferredSpec

the argument may not appear in source Haskell, it is only inferred.

SpecifiedSpec

the argument may appear in source Haskell, but isn't required.

Instances

Instances details
Data Specificity Source # 
Instance details

Defined in GHC.Types.Var

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Specificity -> c Specificity Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Specificity Source #

toConstr :: Specificity -> Constr Source #

dataTypeOf :: Specificity -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Specificity) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Specificity) Source #

gmapT :: (forall b. Data b => b -> b) -> Specificity -> Specificity Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Specificity -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Specificity -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Specificity -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Specificity -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Specificity -> m Specificity Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Specificity -> m Specificity Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Specificity -> m Specificity Source #

Binary Specificity Source # 
Instance details

Defined in GHC.Types.Var

Eq Specificity Source # 
Instance details

Defined in GHC.Types.Var

Ord Specificity Source # 
Instance details

Defined in GHC.Types.Var

OutputableBndrFlag Specificity p Source # 
Instance details

Defined in GHC.Hs.Type

Outputable tv => Outputable (VarBndr tv Specificity) Source # 
Instance details

Defined in GHC.Types.Var

type TyVar = Var Source #

Type or kind Variable

type PredType = Type Source #

A type of the form p of constraint kind represents a value whose type is the Haskell predicate p, where a predicate is what occurs before the => in a Haskell type.

We use PredType as documentation to mark those types that we guarantee to have this kind.

It can be expanded into its representation, but:

  • The type checker must treat it as opaque
  • The rest of the compiler treats it as transparent

Consider these examples:

f :: (Eq a) => a -> Int
g :: (?x :: Int -> Int) => a -> Int
h :: (r\l) => {r} => {l::Int | r}

Here the Eq a and ?x :: Int -> Int and rl are all called "predicates"

type ThetaType = [PredType] Source #

A collection of PredTypes

data Var Source #

Variable

Essentially a typed Name, that may also contain some additional information about the Var and its use sites.

Instances

Instances details
Data Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Var -> c Var Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Var Source #

toConstr :: Var -> Constr Source #

dataTypeOf :: Var -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Var) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Var) Source #

gmapT :: (forall b. Data b => b -> b) -> Var -> Var Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Var -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Var -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Var -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Var -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Var -> m Var Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Var -> m Var Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Var -> m Var Source #

NamedThing Var Source # 
Instance details

Defined in GHC.Types.Var

HasOccName Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

occName :: Var -> OccName Source #

Uniquable Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

getUnique :: Var -> Unique Source #

Outputable Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

ppr :: Var -> SDoc Source #

OutputableBndr Var Source # 
Instance details

Defined in GHC.Core.Ppr

Eq Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

(==) :: Var -> Var -> Bool #

(/=) :: Var -> Var -> Bool #

Ord Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

compare :: Var -> Var -> Ordering #

(<) :: Var -> Var -> Bool #

(<=) :: Var -> Var -> Bool #

(>) :: Var -> Var -> Bool #

(>=) :: Var -> Var -> Bool #

max :: Var -> Var -> Var #

min :: Var -> Var -> Var #

Eq (DeBruijn CoreAlt) Source # 
Instance details

Defined in GHC.Core.Map.Expr

Eq (DeBruijn CoreExpr) Source # 
Instance details

Defined in GHC.Core.Map.Expr

Eq (DeBruijn Var) Source # 
Instance details

Defined in GHC.Core.Map.Type

OutputableBndr (Id, TagSig) Source # 
Instance details

Defined in GHC.Stg.InferTags.TagSig

type Anno Id Source # 
Instance details

Defined in GHC.Hs.Extension

type Anno (LocatedN Id) Source # 
Instance details

Defined in GHC.Hs.Binds

type Anno [LocatedN Id] Source # 
Instance details

Defined in GHC.Hs.Binds

type TyCoVar = Id Source #

Type or Coercion Variable

data Subst Source #

Type & coercion & id substitution

The Subst data type defined in this module contains substitution for tyvar, covar and id. However, operations on IdSubstEnv (mapping from Id to CoreExpr) that require the definition of the Expr data type are defined in GHC.Core.Subst to avoid circular module dependency.

Instances

Instances details
Outputable Subst Source # 
Instance details

Defined in GHC.Core.TyCo.Subst

Methods

ppr :: Subst -> SDoc Source #

type Mult = Type Source #

Mult is a type alias for Type.

Mult must contain Type because multiplicity variables are mere type variables (of kind Multiplicity) in Haskell. So the simplest implementation is to make Mult be Type.

Multiplicities can be formed with: - One: GHC.Types.One (= oneDataCon) - Many: GHC.Types.Many (= manyDataCon) - Multiplication: GHC.Types.MultMul (= multMulTyCon)

So that Mult feels a bit more structured, we provide pattern synonyms and smart constructors for these.

data Scaled a Source #

A shorthand for data with an attached Mult element (the multiplicity).

Instances

Instances details
Data a => Data (Scaled a) Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Scaled a -> c (Scaled a) Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Scaled a) Source #

toConstr :: Scaled a -> Constr Source #

dataTypeOf :: Scaled a -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Scaled a)) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Scaled a)) Source #

gmapT :: (forall b. Data b => b -> b) -> Scaled a -> Scaled a Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Scaled a -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Scaled a -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Scaled a -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Scaled a -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Scaled a -> m (Scaled a) Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Scaled a -> m (Scaled a) Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Scaled a -> m (Scaled a) Source #

Outputable a => Outputable (Scaled a) Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Methods

ppr :: Scaled a -> SDoc Source #

data PiTyBinder Source #

A PiTyBinder represents an argument to a function. PiTyBinders can be dependent (Named) or nondependent (Anon). They may also be visible or not. See Note [PiTyBinders]

Instances

Instances details
Data PiTyBinder Source # 
Instance details

Defined in GHC.Types.Var

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> PiTyBinder -> c PiTyBinder Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c PiTyBinder Source #

toConstr :: PiTyBinder -> Constr Source #

dataTypeOf :: PiTyBinder -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c PiTyBinder) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c PiTyBinder) Source #

gmapT :: (forall b. Data b => b -> b) -> PiTyBinder -> PiTyBinder Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> PiTyBinder -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> PiTyBinder -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> PiTyBinder -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> PiTyBinder -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> PiTyBinder -> m PiTyBinder Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> PiTyBinder -> m PiTyBinder Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> PiTyBinder -> m PiTyBinder Source #

Outputable PiTyBinder Source # 
Instance details

Defined in GHC.Types.Var

Methods

ppr :: PiTyBinder -> SDoc Source #

type TvSubstEnv = TyVarEnv Type Source #

A substitution of Types for TyVars and Kinds for KindVars

type IdSubstEnv = IdEnv CoreExpr Source #

A substitution of Exprs for non-coercion Ids

type KindOrType = Type Source #

The key representation of types within the compiler

type RuntimeRepType = Type Source #

Type synonym used for types of kind RuntimeRep.

type KnotTied ty = ty Source #

A type labeled KnotTied might have knot-tied tycons in it. See Note [Type checking recursive type and class declarations] in GHC.Tc.TyCl

data ForAllTyFlag Source #

ForAllTyFlag

Is something required to appear in source Haskell (Required), permitted by request (Specified) (visible type application), or prohibited entirely from appearing in source Haskell (Inferred)? See Note [VarBndrs, ForAllTyBinders, TyConBinders, and visibility] in GHC.Core.TyCo.Rep

Bundled Patterns

pattern Specified :: ForAllTyFlag 
pattern Inferred :: ForAllTyFlag 

Instances

Instances details
Data ForAllTyFlag Source # 
Instance details

Defined in GHC.Types.Var

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> ForAllTyFlag -> c ForAllTyFlag Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c ForAllTyFlag Source #

toConstr :: ForAllTyFlag -> Constr Source #

dataTypeOf :: ForAllTyFlag -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c ForAllTyFlag) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c ForAllTyFlag) Source #

gmapT :: (forall b. Data b => b -> b) -> ForAllTyFlag -> ForAllTyFlag Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> ForAllTyFlag -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> ForAllTyFlag -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> ForAllTyFlag -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> ForAllTyFlag -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> ForAllTyFlag -> m ForAllTyFlag Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> ForAllTyFlag -> m ForAllTyFlag Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> ForAllTyFlag -> m ForAllTyFlag Source #

Binary ForAllTyFlag Source # 
Instance details

Defined in GHC.Types.Var

Outputable ForAllTyFlag Source # 
Instance details

Defined in GHC.Types.Var

Eq ForAllTyFlag Source # 
Instance details

Defined in GHC.Types.Var

Ord ForAllTyFlag Source # 
Instance details

Defined in GHC.Types.Var

Outputable tv => Outputable (VarBndr tv ForAllTyFlag) Source # 
Instance details

Defined in GHC.Types.Var

data FunTyFlag Source #

The non-dependent version of ForAllTyFlag. See Note [FunTyFlag] Appears here partly so that it's together with its friends ForAllTyFlag and ForallVisFlag, but also because it is used in IfaceType, rather early in the compilation chain

Constructors

FTF_T_T 
FTF_T_C 
FTF_C_T 
FTF_C_C 

Instances

Instances details
Data FunTyFlag Source # 
Instance details

Defined in GHC.Types.Var

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> FunTyFlag -> c FunTyFlag Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c FunTyFlag Source #

toConstr :: FunTyFlag -> Constr Source #

dataTypeOf :: FunTyFlag -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c FunTyFlag) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c FunTyFlag) Source #

gmapT :: (forall b. Data b => b -> b) -> FunTyFlag -> FunTyFlag Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> FunTyFlag -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> FunTyFlag -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> FunTyFlag -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> FunTyFlag -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> FunTyFlag -> m FunTyFlag Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> FunTyFlag -> m FunTyFlag Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> FunTyFlag -> m FunTyFlag Source #

Binary FunTyFlag Source # 
Instance details

Defined in GHC.Types.Var

Outputable FunTyFlag Source # 
Instance details

Defined in GHC.Types.Var

Methods

ppr :: FunTyFlag -> SDoc Source #

Eq FunTyFlag Source # 
Instance details

Defined in GHC.Types.Var

Ord FunTyFlag Source # 
Instance details

Defined in GHC.Types.Var

data TyCoFolder env a Source #

Constructors

TyCoFolder 

Fields

type ForAllTyBinder = VarBndr TyCoVar ForAllTyFlag Source #

Variable Binder

A ForAllTyBinder is the binder of a ForAllTy It's convenient to define this synonym here rather its natural home in GHC.Core.TyCo.Rep, because it's used in GHC.Core.DataCon.hs-boot

A TyVarBinder is a binder with only TyVar

data TyCoMapper env m Source #

This describes how a "map" operation over a type/coercion should behave

Constructors

TyCoMapper 

Fields

pattern OneTy :: Mult Source #

pattern ManyTy :: Mult Source #

funResultTy :: HasDebugCallStack => Type -> Type Source #

Extract the function result type and panic if that is not possible

splitTyConApp :: Type -> (TyCon, [Type]) Source #

Attempts to tease a type apart into a type constructor and the application of a number of arguments to that constructor. Panics if that is not possible. See also splitTyConApp_maybe

isAlgType :: Type -> Bool Source #

See Type for what an algebraic type is. Should only be applied to types, as opposed to e.g. partially saturated type constructors

splitForAllTyCoVars :: Type -> ([TyCoVar], Type) Source #

Take a ForAllTy apart, returning the list of tycovars and the result type. This always succeeds, even if it returns only an empty list. Note that the result type returned may have free variables that were bound by a forall.

mkForAllTys :: [ForAllTyBinder] -> Type -> Type Source #

Wraps foralls over the type using the provided TyCoVars from left to right

argsHaveFixedRuntimeRep :: Type -> Bool Source #

True if the argument types of this function type all have a fixed-runtime-rep

mkTyConApp :: TyCon -> [Type] -> Type Source #

A key function: builds a TyConApp or FunTy as appropriate to its arguments. Applies its arguments to the constructor from left to right.

getLevity :: HasDebugCallStack => Type -> Type Source #

Extract the PromDataConInfo of a type. For example, getLevity Int = Lifted, or getLevity (Array# Int) = Unlifted.

Panics if this is not possible. Does not look through type family applications.

binderVar :: VarBndr tv argf -> tv Source #

binderVars :: [VarBndr tv argf] -> [tv] Source #

mkTyVarBinder :: vis -> TyVar -> VarBndr TyVar vis Source #

Make a named binder var should be a type variable

mkTyVarBinders :: vis -> [TyVar] -> [VarBndr TyVar vis] Source #

Make many named binders Input vars should be type variables

substCo :: HasDebugCallStack => Subst -> Coercion -> Coercion Source #

Substitute within a Coercion The substitution has to satisfy the invariants described in Note [The substitution invariant].

unrestricted :: a -> Scaled a Source #

Scale a payload by Many

linear :: a -> Scaled a Source #

Scale a payload by One

tymult :: a -> Scaled a Source #

Scale a payload by Many; used for type arguments in core

mkScaled :: Mult -> a -> Scaled a Source #

scaledSet :: Scaled a -> b -> Scaled b Source #

mightBeUnliftedType :: Type -> Bool Source #

Returns:

  • False if the type is guaranteed lifted or
  • True if it is unlifted, OR we aren't sure (e.g. in a representation-polymorphic case)

closeOverKindsDSet :: DTyVarSet -> DTyVarSet Source #

Add the kind variables free in the kinds of the tyvars in the given set. Returns a deterministic set.

typeHasFixedRuntimeRep :: HasDebugCallStack => Type -> Bool Source #

Returns True if a type has a syntactically fixed runtime rep, as per Note [Fixed RuntimeRep] in GHC.Tc.Utils.Concrete.

This function is equivalent to `isFixedRuntimeRepKind . typeKind` but much faster.

Precondition: The type has kind (TYPE blah)

extendCvSubst :: Subst -> CoVar -> Coercion -> Subst Source #

Add a substitution from a CoVar to a Coercion to the Subst: you must ensure that the in-scope set satisfies Note [The substitution invariant] after extending the substitution like this

zapSubst :: Subst -> Subst Source #

Remove all substitutions that might have been built up while preserving the in-scope set originally called zapSubstEnv

getTyVar_maybe :: Type -> Maybe TyVar Source #

Attempts to obtain the type variable underlying a Type

tcSplitTyConApp_maybe :: HasCallStack => Type -> Maybe (TyCon, [Type]) Source #

tcSplitTyConApp_maybe splits a type constructor application into its type constructor and applied types.

Differs from splitTyConApp_maybe in that it does *not* split types headed with (=>), as that's not a TyCon in the type-checker.

Note that this may fail (in funTyConAppTy_maybe) in the case of a FunTy with an argument of unknown kind FunTy (e.g. `FunTy (a :: k) Int`, since the kind of a isn't of the form `TYPE rep`. This isn't usually a problem but may be temporarily the cas during canonicalization: see Note [Decomposing FunTy] in GHC.Tc.Solver.Canonical and Note [The Purely Kinded Type Invariant (PKTI)] in GHC.Tc.Gen.HsType, Wrinkle around FunTy

Consequently, you may need to zonk your type before using this function.

seqType :: Type -> () Source #

isTyVar :: Var -> Bool Source #

Is this a type-level (i.e., computationally irrelevant, thus erasable) variable? Satisfies isTyVar = not . isId.

substTyUnchecked :: Subst -> Type -> Type Source #

Substitute within a Type disabling the sanity checks. The problems that the sanity checks in substTy catch are described in Note [The substitution invariant]. The goal of #11371 is to migrate all the calls of substTyUnchecked to substTy and remove this function. Please don't use in new code.

extendSubstInScope :: Subst -> Var -> Subst Source #

Add the Var to the in-scope set

extendSubstInScopeList :: Subst -> [Var] -> Subst Source #

Add the Vars to the in-scope set: see also extendInScope

extendSubstInScopeSet :: Subst -> VarSet -> Subst Source #

Add the Vars to the in-scope set: see also extendInScope

getSubstInScope :: Subst -> InScopeSet Source #

Find the in-scope set: see Note [The substitution invariant]

coreView :: Type -> Maybe Type Source #

This function strips off the top layer only of a type synonym application (if any) its underlying representation type. Returns Nothing if there is nothing to look through.

This function does not look through type family applications.

By being non-recursive and inlined, this case analysis gets efficiently joined onto the case analysis that the caller is already doing

tcSplitAppTyNoView_maybe :: Type -> Maybe (Type, Type) Source #

Just like splitAppTyNoView_maybe, but does not split (c => t) See Note [Decomposing fat arrow c=>t]

splitAppTyNoView_maybe :: HasDebugCallStack => Type -> Maybe (Type, Type) Source #

Does the AppTy split as in splitAppTy_maybe, but assumes that any coreView stuff is already done

tyCoVarsOfTypeDSet :: Type -> DTyCoVarSet Source #

tyCoFVsOfType that returns free variables of a type in a deterministic set. For explanation of why using VarSet is not deterministic see Note [Deterministic FV] in GHC.Utils.FV.

tyCoFVsOfType :: Type -> FV Source #

The worker for tyCoFVsOfType and tyCoFVsOfTypeList. The previous implementation used unionVarSet which is O(n+m) and can make the function quadratic. It's exported, so that it can be composed with other functions that compute free variables. See Note [FV naming conventions] in GHC.Utils.FV.

Eta-expanded because that makes it run faster (apparently) See Note [FV eta expansion] in GHC.Utils.FV for explanation.

tyConsOfType :: Type -> UniqSet TyCon Source #

All type constructors occurring in the type; looking through type synonyms, but not newtypes. When it finds a Class, it returns the class TyCon.

scopedSort :: [TyCoVar] -> [TyCoVar] Source #

Do a topological sort on a list of tyvars, so that binders occur before occurrences E.g. given [ a::k, k::*, b::k ] it'll return a well-scoped list [ k::*, a::k, b::k ]

This is a deterministic sorting operation (that is, doesn't depend on Uniques).

It is also meant to be stable: that is, variables should not be reordered unnecessarily. This is specified in Note [ScopedSort] See also Note [Ordering of implicit variables] in GHC.Rename.HsType

tyCoVarsOfTypeWellScoped :: Type -> [TyVar] Source #

Get the free vars of a type in scoped order

tyCoVarsOfTypesWellScoped :: [Type] -> [TyVar] Source #

Get the free vars of types in scoped order

closeOverKindsList :: [TyVar] -> [TyVar] Source #

Add the kind variables free in the kinds of the tyvars in the given set. Returns a deterministically ordered list.

partitionInvisibleTypes :: TyCon -> [Type] -> ([Type], [Type]) Source #

Given a TyCon and a list of argument types, partition the arguments into:

  1. Inferred or Specified (i.e., invisible) arguments and
  2. Required (i.e., visible) arguments

splitForAllReqTyBinders :: Type -> ([ReqTyBinder], Type) Source #

Like splitForAllTyCoVars, but only splits ForAllTys with Required type variable binders. Furthermore, each returned tyvar is annotated with ().

splitForAllInvisTyBinders :: Type -> ([InvisTyBinder], Type) Source #

Like splitForAllTyCoVars, but only splits ForAllTys with Invisible type variable binders. Furthermore, each returned tyvar is annotated with its Specificity.

mkForAllTy :: ForAllTyBinder -> Type -> Type Source #

Like mkTyCoForAllTy, but does not check the occurrence of the binder See Note [Unused coercion variable in ForAllTy]

mkInvisForAllTys :: [InvisTVBinder] -> Type -> Type Source #

Wraps foralls over the type using the provided InvisTVBinders from left to right

mkVisFunTyMany :: HasDebugCallStack => Type -> Type -> Type infixr 3 Source #

Make nested arrow types | Special, common, case: Arrow type with mult Many

foldTyCo :: Monoid a => TyCoFolder env a -> env -> (Type -> a, [Type] -> a, Coercion -> a, [Coercion] -> a) Source #

noView :: Type -> Maybe Type Source #

A view function that looks through nothing.

chooseFunTyFlag :: HasDebugCallStack => Type -> Type -> FunTyFlag Source #

See GHC.Types.Var Note [FunTyFlag]

composeTCvSubst :: Subst -> Subst -> Subst Source #

Composes two substitutions, applying the second one provided first, like in function composition. This function leaves IdSubstEnv untouched because IdSubstEnv is not used during substitution for types.

isEmptyTCvSubst :: Subst -> Bool Source #

Checks whether the tyvar and covar environments are empty. This function should be used over isEmptySubst when substituting for types, because types currently do not contain expressions; we can safely disregard the expression environment when deciding whether to skip a substitution. Using isEmptyTCvSubst gives us a non-trivial performance boost (up to 70% less allocation for T18223)

getSubstRangeTyCoFVs :: Subst -> VarSet Source #

Returns the free variables of the types in the range of a substitution as a non-deterministic set.

zipTyEnv :: HasDebugCallStack => [TyVar] -> [Type] -> TvSubstEnv Source #

The InScopeSet is just a thunk so with a bit of luck it'll never be evaluated

zipTvSubst :: HasDebugCallStack => [TyVar] -> [Type] -> Subst Source #

Generates the in-scope set for the Subst from the types in the incoming environment. No CoVars or Ids, please!

mkTvSubstPrs :: [(TyVar, Type)] -> Subst Source #

Generates the in-scope set for the TCvSubst from the types in the incoming environment. No CoVars, please! The InScopeSet is just a thunk so with a bit of luck it'll never be evaluated

substTyWith :: HasDebugCallStack => [TyVar] -> [Type] -> Type -> Type Source #

Type substitution, see zipTvSubst

substTysWith :: [TyVar] -> [Type] -> [Type] -> [Type] Source #

Type substitution, see zipTvSubst

substTyAddInScope :: Subst -> Type -> Type Source #

Substitute within a Type after adding the free variables of the type to the in-scope set. This is useful for the case when the free variables aren't already in the in-scope set or easily available. See also Note [The substitution invariant].

substTysUnchecked :: Subst -> [Type] -> [Type] Source #

Substitute within several Types disabling the sanity checks. The problems that the sanity checks in substTys catch are described in Note [The substitution invariant]. The goal of #11371 is to migrate all the calls of substTysUnchecked to substTys and remove this function. Please don't use in new code.

substThetaUnchecked :: Subst -> ThetaType -> ThetaType Source #

Substitute within a ThetaType disabling the sanity checks. The problems that the sanity checks in substTys catch are described in Note [The substitution invariant]. The goal of #11371 is to migrate all the calls of substThetaUnchecked to substTheta and remove this function. Please don't use in new code.

substTyWithUnchecked :: [TyVar] -> [Type] -> Type -> Type Source #

Type substitution, see zipTvSubst. Disables sanity checks. The problems that the sanity checks in substTy catch are described in Note [The substitution invariant]. The goal of #11371 is to migrate all the calls of substTyUnchecked to substTy and remove this function. Please don't use in new code.

substCoUnchecked :: Subst -> Coercion -> Coercion Source #

Substitute within a Coercion disabling sanity checks. The problems that the sanity checks in substCo catch are described in Note [The substitution invariant]. The goal of #11371 is to migrate all the calls of substCoUnchecked to substCo and remove this function. Please don't use in new code.

substCoWithUnchecked :: [TyVar] -> [Type] -> Coercion -> Coercion Source #

Coercion substitution, see zipTvSubst. Disables sanity checks. The problems that the sanity checks in substCo catch are described in Note [The substitution invariant]. The goal of #11371 is to migrate all the calls of substCoUnchecked to substCo and remove this function. Please don't use in new code.

substTys :: HasDebugCallStack => Subst -> [Type] -> [Type] Source #

Substitute within several Types The substitution has to satisfy the invariants described in Note [The substitution invariant].

substTheta :: HasDebugCallStack => Subst -> ThetaType -> ThetaType Source #

Substitute within a ThetaType The substitution has to satisfy the invariants described in Note [The substitution invariant].

mkCastTy :: Type -> Coercion -> Type Source #

Make a CastTy. The Coercion must be nominal. Checks the Coercion for reflexivity, dropping it if it's reflexive. See Note [Respecting definitional equality] in GHC.Core.TyCo.Rep

mkAppTy :: Type -> Type -> Type Source #

Applies a type to another, as in e.g. k a

tidyType :: TidyEnv -> Type -> Type Source #

Tidy a Type

See Note [Strictness in tidyType and friends]

tidyTypes :: TidyEnv -> [Type] -> [Type] Source #

Tidy a list of Types

See Note [Strictness in tidyType and friends]

tidyOpenTypes :: TidyEnv -> [Type] -> (TidyEnv, [Type]) Source #

Grabs the free type variables, tidies them and then uses tidyType to work over the type itself

tidyVarBndrs :: TidyEnv -> [TyCoVar] -> (TidyEnv, [TyCoVar]) Source #

This tidies up a type for printing in an error message, or in an interface file.

It doesn't change the uniques at all, just the print names.

tidyFreeTyCoVars :: TidyEnv -> [TyCoVar] -> TidyEnv Source #

Add the free TyVars to the env in tidy form, so that we can tidy the type they are free in

tidyOpenTyCoVar :: TidyEnv -> TyCoVar -> (TidyEnv, TyCoVar) Source #

Treat a new TyCoVar as a binder, and give it a fresh tidy name using the environment if one has not already been allocated. See also tidyVarBndr

tidyTopType :: Type -> Type Source #

Calls tidyType on a top-level type (i.e. with an empty tidying environment)

mkTyConTy :: TyCon -> Type Source #

(mkTyConTy tc) returns (TyConApp tc []) but arranges to share that TyConApp among all calls See Note [Sharing nullary TyConApps] So it's just an alias for tyConNullaryTy!

isLiftedTypeKind :: Kind -> Bool Source #

Returns True if the argument is (lifted) Type or Constraint See Note [TYPE and CONSTRAINT] in GHC.Builtin.Types.Prim

getTyVar :: HasDebugCallStack => Type -> TyVar Source #

Attempts to obtain the type variable underlying a Type, and panics with the given message if this is not a type variable type. See also getTyVar_maybe

repGetTyVar_maybe :: Type -> Maybe TyVar Source #

Attempts to obtain the type variable underlying a Type, without any expansion

getCastedTyVar_maybe :: Type -> Maybe (TyVar, CoercionN) Source #

If the type is a tyvar, possibly under a cast, returns it, along with the coercion. Thus, the co is :: kind tv ~N kind ty

splitAppTy :: Type -> (Type, Type) Source #

Attempts to take a type application apart, as in splitAppTy_maybe, and panics if this is not possible

splitAppTys :: Type -> (Type, [Type]) Source #

Recursively splits a type as far as is possible, leaving a residual type being applied to and the type arguments applied to it. Never fails, even if that means returning an empty list of type applications.

splitAppTysNoView :: HasDebugCallStack => Type -> (Type, [Type]) Source #

Like splitAppTys, but doesn't look through type synonyms

splitAppTy_maybe :: Type -> Maybe (Type, Type) Source #

Attempt to take a type application apart, whether it is a function, type constructor, or plain type application. Note that type family applications are NEVER unsaturated by this!

splitFunTy :: Type -> (Mult, Type, Type) Source #

Attempts to extract the multiplicity, argument and result types from a type, and panics if that is not possible. See also splitFunTy_maybe

splitFunTy_maybe :: Type -> Maybe (FunTyFlag, Mult, Type, Type) Source #

Attempts to extract the multiplicity, argument and result types from a type

funArgTy :: Type -> Type Source #

Just like piResultTys but for a single argument Try not to iterate piResultTy, because it's inefficient to substitute one variable at a time; instead use 'piResultTys"

Extract the function argument type and panic if that is not possible

funTyConAppTy_maybe :: FunTyFlag -> Type -> Type -> Type -> Maybe (TyCon, [Type]) Source #

Given the components of a FunTy figure out the corresponding TyConApp.

tyConAppFunTy_maybe :: HasDebugCallStack => TyCon -> [Type] -> Maybe Type Source #

Return Just if this TyConApp should be represented as a FunTy

tyConAppFunCo_maybe :: HasDebugCallStack => Role -> TyCon -> [Coercion] -> Maybe Coercion Source #

Return Just if this TyConAppCo should be represented as a FunCo

mkFunctionType :: HasDebugCallStack => Mult -> Type -> Type -> Type Source #

This one works out the FunTyFlag from the argument type See GHC.Types.Var Note [FunTyFlag]

mkScaledFunctionTys :: [Scaled Type] -> Type -> Type Source #

Like mkFunctionType, compute the FunTyFlag from the arguments

tyConAppTyCon_maybe :: Type -> Maybe TyCon Source #

The same as fst . splitTyConApp We can short-cut the FunTy case

tyConAppTyConPicky_maybe :: Type -> Maybe TyCon Source #

Retrieve the tycon heading this type, if there is one. Does not look through synonyms.

tyConAppArgs_maybe :: Type -> Maybe [Type] Source #

The same as snd . splitTyConApp

splitTyConApp_maybe :: HasDebugCallStack => Type -> Maybe (TyCon, [Type]) Source #

Attempts to tease a type apart into a type constructor and the application of a number of arguments to that constructor

mkTyCoInvForAllTys :: [TyCoVar] -> Type -> Type Source #

Like mkForAllTys, but assumes all variables are dependent and Inferred, a common case

mkSpecForAllTy :: TyVar -> Type -> Type Source #

Like mkForAllTy, but assumes the variable is dependent and Specified, a common case

mkSpecForAllTys :: [TyVar] -> Type -> Type Source #

Like mkForAllTys, but assumes all variables are dependent and Specified, a common case

mkVisForAllTys :: [TyVar] -> Type -> Type Source #

Like mkForAllTys, but assumes all variables are dependent and visible

mkTyCoInvForAllTy :: TyCoVar -> Type -> Type Source #

Make a dependent forall over an Inferred variable

mkInfForAllTy :: TyVar -> Type -> Type Source #

Like mkTyCoInvForAllTy, but tv should be a tyvar

mkInfForAllTys :: [TyVar] -> Type -> Type Source #

Like mkTyCoInvForAllTys, but tvs should be a list of tyvar

splitForAllTyVars :: Type -> ([TyVar], Type) Source #

Like splitForAllTyCoVars, but split only for tyvars. This always succeeds, even if it returns only an empty list. Note that the result type returned may have free variables that were bound by a forall.

splitForAllForAllTyBinders :: Type -> ([ForAllTyBinder], Type) Source #

Take a ForAllTy apart, returning the binders and result type

splitForAllTyCoVar_maybe :: Type -> Maybe (TyCoVar, Type) Source #

Attempts to take a forall type apart, but only if it's a proper forall, with a named binder

splitForAllTyCoVar :: Type -> (TyCoVar, Type) Source #

Take a forall type apart, or panics if that is not possible.

splitForAllTyVar_maybe :: Type -> Maybe (TyVar, Type) Source #

Like splitForAllTyCoVar_maybe, but only returns Just if it is a tyvar binder.

splitForAllCoVar_maybe :: Type -> Maybe (CoVar, Type) Source #

Like splitForAllTyCoVar_maybe, but only returns Just if it is a covar binder.

splitPiTy_maybe :: Type -> Maybe (PiTyBinder, Type) Source #

Attempts to take a forall type apart; works with proper foralls and functions

splitPiTy :: Type -> (PiTyBinder, Type) Source #

Takes a forall type apart, or panics

splitPiTys :: Type -> ([PiTyBinder], Type) Source #

Split off all PiTyBinders to a type, splitting both proper foralls and functions

getRuntimeArgTys :: Type -> [(Scaled Type, FunTyFlag)] Source #

Extracts a list of run-time arguments from a function type, looking through newtypes to the right of arrows.

Examples:

   newtype Identity a = I a

   getRuntimeArgTys (Int -> Bool -> Double) == [(Int, FTF_T_T), (Bool, FTF_T_T)]
   getRuntimeArgTys (Identity Int -> Bool -> Double) == [(Identity Int, FTF_T_T), (Bool, FTF_T_T)]
   getRuntimeArgTys (Int -> Identity (Bool -> Identity Double)) == [(Int, FTF_T_T), (Bool, FTF_T_T)]
   getRuntimeArgTys (forall a. Show a => Identity a -> a -> Int -> Bool)
            == [(Show a, FTF_C_T), (Identity a, FTF_T_T),(a, FTF_T_T),(Int, FTF_T_T)]

Note that, in the last case, the returned types might mention an out-of-scope type variable. This function is used only when we really care about the kinds of the returned types, so this is OK.

  • *Warning**: this function can return an infinite list. For example:
  newtype N a = MkN (a -> N a)
  getRuntimeArgTys (N a) == repeat (a, FTF_T_T)

mkTyConBindersPreferAnon Source #

Arguments

:: [TyVar]

binders

-> TyCoVarSet

free variables of result

-> [TyConBinder] 

Given a list of type-level vars and the free vars of a result kind, makes PiTyBinders, preferring anonymous binders if the variable is, in fact, not dependent. e.g. mkTyConBindersPreferAnon (k:*),(b:k),(c:k) We want (k:*) Named, (b:k) Anon, (c:k) Anon

All non-coercion binders are visible.

piResultTys :: HasDebugCallStack => Type -> [Type] -> Type Source #

(piResultTys f_ty [ty1, .., tyn]) gives the type of (f ty1 .. tyn) where f :: f_ty piResultTys is interesting because: 1. f_ty may have more for-alls than there are args 2. Less obviously, it may have fewer for-alls For case 2. think of: piResultTys (forall a.a) [forall b.b, Int] This really can happen, but only (I think) in situations involving undefined. For example: undefined :: forall a. a Term: undefined (forall b. b->b) Int This term should have type (Int -> Int), but notice that there are more type args than foralls in undefineds type.

dropForAlls :: Type -> Type Source #

Drops all ForAllTys

mkFamilyTyConApp :: TyCon -> [Type] -> Type Source #

Given a family instance TyCon and its arg types, return the corresponding family type. E.g:

data family T a
data instance T (Maybe b) = MkT b

Where the instance tycon is :RTL, so:

mkFamilyTyConApp :RTL Int  =  T (Maybe Int)

buildSynTyCon Source #

Arguments

:: Name 
-> [KnotTied TyConBinder] 
-> Kind

result kind

-> [Role] 
-> KnotTied Type 
-> TyCon 

isNumLitTy :: Type -> Maybe Integer Source #

Is this a numeric literal. We also look through type synonyms.

isStrLitTy :: Type -> Maybe FastString Source #

Is this a symbol literal. We also look through type synonyms.

isCharLitTy :: Type -> Maybe Char Source #

Is this a char literal? We also look through type synonyms.

isLitTy :: Type -> Maybe TyLit Source #

Is this a type literal (symbol, numeric, or char)?

getRuntimeRep :: HasDebugCallStack => Type -> RuntimeRepType Source #

Extract the RuntimeRep classifier of a type. For instance, getRuntimeRep_maybe Int = LiftedRep. Panics if this is not possible.

splitRuntimeRep_maybe :: RuntimeRepType -> Maybe (TyCon, [Type]) Source #

(splitRuntimeRep_maybe rr) takes a Type rr :: RuntimeRep, and returns the (TyCon,[Type]) for the RuntimeRep, if possible, where the TyCon is one of the promoted DataCons of RuntimeRep. Remember: the unique on TyCon that is a a promoted DataCon is the same as the unique on the DataCon See Note [Promoted data constructors] in GHC.Core.TyCon May not be possible if rr is a type variable or type family application

kindRep_maybe :: HasDebugCallStack => Kind -> Maybe RuntimeRepType Source #

Given a kind (TYPE rr) or (CONSTRAINT rr), extract its RuntimeRep classifier rr. For example, kindRep_maybe * = Just LiftedRep Returns Nothing if the kind is not of form (TYPE rr)

kindRep :: HasDebugCallStack => Kind -> RuntimeRepType Source #

Extract the RuntimeRep classifier of a type from its kind. For example, kindRep * = LiftedRep; Panics if this is not possible. Treats * and Constraint as the same

levityType_maybe :: LevityType -> Maybe Levity Source #

levity_maybe takes a Type of kind Levity, and returns its levity May not be possible for a type variable or type family application

userTypeError_maybe :: Type -> Maybe Type Source #

Is this type a custom user error? If so, give us the kind and the error message.

pprUserTypeErrorTy :: Type -> SDoc Source #

Render a type corresponding to a user type error into a SDoc.

coAxNthLHS :: CoAxiom br -> Int -> Type Source #

Get the type on the LHS of a coercion induced by a type/data family instance.

splitInvisPiTys :: Type -> ([PiTyBinder], Type) Source #

Like splitPiTys, but returns only *invisible* binders, including constraints. Stops at the first visible binder.

splitInvisPiTysN :: Int -> Type -> ([PiTyBinder], Type) Source #

Same as splitInvisPiTys, but stop when - you have found n PiTyBinders, - or you run out of invisible binders

filterOutInvisibleTypes :: TyCon -> [Type] -> [Type] Source #

Given a TyCon and a list of argument types, filter out any invisible (i.e., Inferred or Specified) arguments.

filterOutInferredTypes :: TyCon -> [Type] -> [Type] Source #

Given a TyCon and a list of argument types, filter out any Inferred arguments.

partitionInvisibles :: [(a, ForAllTyFlag)] -> ([a], [a]) Source #

Given a list of things paired with their visibilities, partition the things into (invisible things, visible things).

tyConForAllTyFlags :: TyCon -> [Type] -> [ForAllTyFlag] Source #

Given a TyCon and a list of argument types to which the TyCon is applied, determine each argument's visibility (Inferred, Specified, or Required).

Wrinkle: consider the following scenario:

T :: forall k. k -> k
tyConForAllTyFlags T [forall m. m -> m -> m, S, R, Q]

After substituting, we get

T (forall m. m -> m -> m) :: (forall m. m -> m -> m) -> forall n. n -> n -> n

Thus, the first argument is invisible, S is visible, R is invisible again, and Q is visible.

appTyForAllTyFlags :: Type -> [Type] -> [ForAllTyFlag] Source #

Given a Type and a list of argument types to which the Type is applied, determine each argument's visibility (Inferred, Specified, or Required).

Most of the time, the arguments will be Required, but not always. Consider f :: forall a. a -> Type. In f Type Bool, the first argument (Type) is Specified and the second argument (Bool) is Required. It is precisely this sort of higher-rank situation in which appTyForAllTyFlags comes in handy, since f Type Bool would be represented in Core using AppTys. (See also #15792).

mapTyCo :: Monad m => TyCoMapper () m -> (Type -> m Type, [Type] -> m [Type], Coercion -> m Coercion, [Coercion] -> m [Coercion]) Source #

mapTyCoX :: Monad m => TyCoMapper env m -> (env -> Type -> m Type, env -> [Type] -> m [Type], env -> Coercion -> m Coercion, env -> [Coercion] -> m [Coercion]) Source #

newTyConInstRhs :: TyCon -> [Type] -> Type Source #

Unwrap one layer of newtype on a type constructor and its arguments, using an eta-reduced version of the newtype if possible. This requires tys to have at least newTyConInstArity tycon elements.

mkForAllTyBinder :: vis -> TyCoVar -> VarBndr TyCoVar vis Source #

Make a named binder

mkForAllTyBinders :: vis -> [TyCoVar] -> [VarBndr TyCoVar vis] Source #

Make many named binders

isAnonPiTyBinder :: PiTyBinder -> Bool Source #

Does this binder bind a variable that is not erased? Returns True for anonymous binders.

binderFlag :: VarBndr tv argf -> argf Source #

binderFlags :: [VarBndr tv argf] -> [argf] Source #

anonPiTyBinderType_maybe :: PiTyBinder -> Maybe Type Source #

Extract a relevant type, if there is one.

isVisibleForAllTyFlag :: ForAllTyFlag -> Bool Source #

Does this ForAllTyFlag classify an argument that is written in Haskell?

isInvisibleForAllTyFlag :: ForAllTyFlag -> Bool Source #

Does this ForAllTyFlag classify an argument that is not written in Haskell?

isVisiblePiTyBinder :: PiTyBinder -> Bool Source #

Does this binder bind a visible argument?

isInvisiblePiTyBinder :: PiTyBinder -> Bool Source #

Does this binder bind an invisible argument?

isFunTy :: Type -> Bool Source #

Is this a function?

isForAllTy :: Type -> Bool Source #

Checks whether this is a proper forall (with a named binder)

isForAllTy_ty :: Type -> Bool Source #

Like isForAllTy, but returns True only if it is a tyvar binder

isForAllTy_co :: Type -> Bool Source #

Like isForAllTy, but returns True only if it is a covar binder

isPiTy :: Type -> Bool Source #

Is this a function or forall?

isCoVarType :: Type -> Bool Source #

Does this type classify a core (unlifted) Coercion? At either role nominal or representational (t1 ~# t2) or (t1 ~R# t2) See Note [Types for coercions, predicates, and evidence] in GHC.Core.TyCo.Rep

isValidJoinPointType :: JoinArity -> Type -> Bool Source #

Determine whether a type could be the type of a join point of given total arity, according to the polymorphism rule. A join point cannot be polymorphic in its return type, since given join j a b x y z = e1 in e2, the types of e1 and e2 must be the same, and a and b are not in scope for e2. (See Note [The polymorphism rule of join points] in GHC.Core.) Returns False also if the type simply doesn't have enough arguments.

Note that we need to know how many arguments (type *and* value) the putative join point takes; for instance, if j :: forall a. a -> Int then j could be a binary join point returning an Int, but it could *not* be a unary join point returning a -> Int.

TODO: See Note [Excess polymorphism and join points]

tyConAppNeedsKindSig Source #

Arguments

:: Bool

Should specified binders count towards injective positions in the kind of the TyCon? (If you're using visible kind applications, then you want True here.

-> TyCon 
-> Int

The number of args the TyCon is applied to.

-> Bool

Does T t_1 ... t_n need a kind signature? (Where n is the number of arguments)

Does a TyCon (that is applied to some number of arguments) need to be ascribed with an explicit kind signature to resolve ambiguity if rendered as a source-syntax type? (See Note [When does a tycon application need an explicit kind signature?] for a full explanation of what this function checks for.)

mkTYPEapp_maybe :: RuntimeRepType -> Maybe Type Source #

Given a RuntimeRep, applies TYPE to it. On the fly it rewrites TYPE LiftedRep --> liftedTypeKind (a synonym) TYPE UnliftedRep --> unliftedTypeKind (ditto) TYPE ZeroBitRep --> zeroBitTypeKind (ditto) NB: no need to check for TYPE (BoxedRep Lifted), TYPE (BoxedRep Unlifted) because those inner types should already have been rewritten to LiftedRep and UnliftedRep respectively, by mkTyConApp

see Note [TYPE and CONSTRAINT] in GHC.Builtin.Types.Prim. See Note [Using synonyms to compress types] in GHC.Core.Type

mkCONSTRAINTapp :: RuntimeRepType -> Type Source #

Just like mkTYPEapp

mkCONSTRAINTapp_maybe :: RuntimeRepType -> Maybe Type Source #

Just like mkTYPEapp_maybe

mkBoxedRepApp_maybe :: LevityType -> Maybe Type Source #

Given a PromDataConInfo, apply BoxedRep to it On the fly, rewrite BoxedRep Lifted --> liftedRepTy (a synonym) BoxedRep Unlifted --> unliftedRepTy (ditto) See Note [TYPE and CONSTRAINT] in GHC.Builtin.Types.Prim. See Note [Using synonyms to compress types] in GHC.Core.Type

mkTupleRepApp_maybe :: Type -> Maybe Type Source #

Given a `[RuntimeRep]`, apply TupleRep to it On the fly, rewrite TupleRep [] -> zeroBitRepTy (a synonym) See Note [TYPE and CONSTRAINT] in GHC.Builtin.Types.Prim. See Note [Using synonyms to compress types] in GHC.Core.Type

typeLevity_maybe :: HasDebugCallStack => Type -> Maybe Levity Source #

Tries to compute the PromDataConInfo of the given type. Returns either a definite PromDataConInfo, or Nothing if we aren't sure (e.g. the type is representation-polymorphic).

Panics if the kind does not have the shape TYPE r.

isUnliftedTypeKind :: Kind -> Bool Source #

Returns True if the kind classifies unlifted types (like 'Int#') and False otherwise. Note that this returns False for representation-polymorphic kinds, which may be specialized to a kind that classifies unlifted types.

isLiftedRuntimeRep :: RuntimeRepType -> Bool Source #

Check whether a type of kind RuntimeRep is lifted.

isLiftedRuntimeRep is:

  • True of LiftedRep :: RuntimeRep
  • False of type variables, type family applications, and of other reps such as IntRep :: RuntimeRep.

isUnliftedRuntimeRep :: RuntimeRepType -> Bool Source #

Check whether a type of kind RuntimeRep is unlifted.

runtimeRepLevity_maybe :: RuntimeRepType -> Maybe Levity Source #

Check whether a type of kind RuntimeRep is lifted, unlifted, or unknown.

`isLiftedRuntimeRep rr` returns:

  • `Just Lifted` if rr is `LiftedRep :: RuntimeRep`
  • `Just Unlifted` if rr is definitely unlifted, e.g. IntRep
  • Nothing if not known (e.g. it's a type variable or a type family application).

isBoxedRuntimeRep :: RuntimeRepType -> Bool Source #

See isBoxedRuntimeRep_maybe.

isUnliftedType :: HasDebugCallStack => Type -> Bool Source #

Is the given type definitely unlifted? See Type for what an unlifted type is.

Panics on representation-polymorphic types; See mightBeUnliftedType for a more approximate predicate that behaves better in the presence of representation polymorphism.

isBoxedType :: Type -> Bool Source #

See Type for what a boxed type is. Panics on representation-polymorphic types; See mightBeUnliftedType for a more approximate predicate that behaves better in the presence of representation polymorphism.

kindBoxedRepLevity_maybe :: Type -> Maybe Levity Source #

Check whether a kind is of the form `TYPE (BoxedRep Lifted)` or `TYPE (BoxedRep Unlifted)`.

Returns:

  • `Just Lifted` for `TYPE (BoxedRep Lifted)` and Type,
  • `Just Unlifted` for `TYPE (BoxedRep Unlifted)` and UnliftedType,
  • Nothing for anything else, e.g. `TYPE IntRep`, `TYPE (BoxedRep l)`, etc.

mightBeLiftedType :: Type -> Bool Source #

Returns:

  • False if the type is guaranteed unlifted or
  • True if it lifted, OR we aren't sure (e.g. in a representation-polymorphic case)

isDataFamilyAppType :: Type -> Bool Source #

Check whether a type is a data family type

isPrimitiveType :: Type -> Bool Source #

Returns true of types that are opaque to Haskell.

isStrictType :: HasDebugCallStack => Type -> Bool Source #

Computes whether an argument (or let right hand side) should be computed strictly or lazily, based only on its type. Currently, it's just isUnliftedType. Panics on representation-polymorphic types.

isLevityTy :: Type -> Bool Source #

Is this the type PromDataConInfo?

isLevityVar :: TyVar -> Bool Source #

Is a tyvar of type PromDataConInfo?

isRuntimeRepTy :: Type -> Bool Source #

Is this the type RuntimeRep?

isRuntimeRepVar :: TyVar -> Bool Source #

Is a tyvar of type RuntimeRep?

isRuntimeRepKindedTy :: Type -> Bool Source #

Is this a type of kind RuntimeRep? (e.g. LiftedRep)

dropRuntimeRepArgs :: [Type] -> [Type] Source #

Drops prefix of RuntimeRep constructors in TyConApps. Useful for e.g. dropping 'LiftedRep arguments of unboxed tuple TyCon applications:

dropRuntimeRepArgs [ 'LiftedRep, 'IntRep , String, Int# ] == [String, Int#]

isMultiplicityTy :: Type -> Bool Source #

Is this the type Multiplicity?

isMultiplicityVar :: TyVar -> Bool Source #

Is a tyvar of type Multiplicity?

isLinearType :: Type -> Bool Source #

isLinear t returns True of a if t is a type of (curried) function where at least one argument is linear (or otherwise non-unrestricted). We use this function to check whether it is safe to eta reduce an Id in CorePrep. It is always safe to return True, because True deactivates the optimisation.

tcIsLiftedTypeKind :: Kind -> Bool Source #

Is this kind equivalent to Type i.e. TYPE LiftedRep?

tcIsBoxedTypeKind :: Kind -> Bool Source #

Is this kind equivalent to TYPE (BoxedRep l) for some l :: Levity?

isTypeLikeKind :: Kind -> Bool Source #

Is this kind equivalent to TYPE r (for some unknown r)?

This considers Constraint to be distinct from *.

expandTypeSynonyms :: Type -> Type Source #

Expand out all type synonyms. Actually, it'd suffice to expand out just the ones that discard type variables (e.g. type Funny a = Int) But we don't know which those are currently, so we just expand all.

expandTypeSynonyms only expands out type synonyms mentioned in the type, not in the kinds of any TyCon or TyVar mentioned in the type.

Keep this synchronized with synonymTyConsOfType

seqTypes :: [Type] -> () Source #

isTYPEorCONSTRAINT :: Kind -> Bool Source #

Does this classify a type allowed to have values? Responds True to things like *, TYPE Lifted, TYPE IntRep, TYPE v, Constraint.

True of a kind `TYPE _` or `CONSTRAINT _`

isConcrete :: Type -> Bool Source #

Tests whether the given type is concrete, i.e. it whether it consists only of concrete type constructors, concrete type variables, and applications.

See Note [Concrete types] in GHC.Tc.Utils.Concrete.

isFixedRuntimeRepKind :: HasDebugCallStack => Kind -> Bool Source #

Checks that a kind of the form Type, Constraint or 'TYPE r is concrete. See isConcrete.

Precondition: The type has kind `TYPE blah` or `CONSTRAINT blah`

data Coercion Source #

A Coercion is concrete evidence of the equality/convertibility of two types.

Instances

Instances details
Data Coercion Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Coercion -> c Coercion Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Coercion Source #

toConstr :: Coercion -> Constr Source #

dataTypeOf :: Coercion -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Coercion) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Coercion) Source #

gmapT :: (forall b. Data b => b -> b) -> Coercion -> Coercion Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Coercion -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Coercion -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Coercion -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Coercion -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Coercion -> m Coercion Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Coercion -> m Coercion Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Coercion -> m Coercion Source #

Outputable Coercion Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Methods

ppr :: Coercion -> SDoc Source #

Eq (DeBruijn Coercion) Source # 
Instance details

Defined in GHC.Core.Map.Type

data Role Source #

See Note [Roles] in GHC.Core.Coercion

Order of constructors matters: the Ord instance coincides with the *super*typing relation on roles.

Instances

Instances details
Data Role Source # 
Instance details

Defined in Language.Haskell.Syntax.Basic

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Role -> c Role Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Role Source #

toConstr :: Role -> Constr Source #

dataTypeOf :: Role -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Role) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Role) Source #

gmapT :: (forall b. Data b => b -> b) -> Role -> Role Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Role -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Role -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Role -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Role -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Role -> m Role Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Role -> m Role Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Role -> m Role Source #

Binary Role Source # 
Instance details

Defined in GHC.Core.Coercion.Axiom

Outputable Role Source # 
Instance details

Defined in GHC.Core.Coercion.Axiom

Methods

ppr :: Role -> SDoc Source #

Eq Role Source # 
Instance details

Defined in Language.Haskell.Syntax.Basic

Methods

(==) :: Role -> Role -> Bool #

(/=) :: Role -> Role -> Bool #

Ord Role Source # 
Instance details

Defined in Language.Haskell.Syntax.Basic

Methods

compare :: Role -> Role -> Ordering #

(<) :: Role -> Role -> Bool #

(<=) :: Role -> Role -> Bool #

(>) :: Role -> Role -> Bool #

(>=) :: Role -> Role -> Bool #

max :: Role -> Role -> Role #

min :: Role -> Role -> Role #

type Anno (Maybe Role) Source # 
Instance details

Defined in GHC.Hs.Decls

type Anno (Maybe Role) Source # 
Instance details

Defined in GHC.Hs.Decls

data Var Source #

Variable

Essentially a typed Name, that may also contain some additional information about the Var and its use sites.

Instances

Instances details
Data Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Var -> c Var Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Var Source #

toConstr :: Var -> Constr Source #

dataTypeOf :: Var -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Var) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Var) Source #

gmapT :: (forall b. Data b => b -> b) -> Var -> Var Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Var -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Var -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Var -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Var -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Var -> m Var Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Var -> m Var Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Var -> m Var Source #

NamedThing Var Source # 
Instance details

Defined in GHC.Types.Var

HasOccName Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

occName :: Var -> OccName Source #

Uniquable Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

getUnique :: Var -> Unique Source #

Outputable Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

ppr :: Var -> SDoc Source #

OutputableBndr Var Source # 
Instance details

Defined in GHC.Core.Ppr

Eq Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

(==) :: Var -> Var -> Bool #

(/=) :: Var -> Var -> Bool #

Ord Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

compare :: Var -> Var -> Ordering #

(<) :: Var -> Var -> Bool #

(<=) :: Var -> Var -> Bool #

(>) :: Var -> Var -> Bool #

(>=) :: Var -> Var -> Bool #

max :: Var -> Var -> Var #

min :: Var -> Var -> Var #

Eq (DeBruijn CoreAlt) Source # 
Instance details

Defined in GHC.Core.Map.Expr

Eq (DeBruijn CoreExpr) Source # 
Instance details

Defined in GHC.Core.Map.Expr

Eq (DeBruijn Var) Source # 
Instance details

Defined in GHC.Core.Map.Type

OutputableBndr (Id, TagSig) Source # 
Instance details

Defined in GHC.Stg.InferTags.TagSig

type Anno Id Source # 
Instance details

Defined in GHC.Hs.Extension

type Anno (LocatedN Id) Source # 
Instance details

Defined in GHC.Hs.Binds

type Anno [LocatedN Id] Source # 
Instance details

Defined in GHC.Hs.Binds

data MCoercion Source #

A semantically more meaningful type to represent what may or may not be a useful Coercion.

Constructors

MRefl 
MCo Coercion 

Instances

Instances details
Data MCoercion Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> MCoercion -> c MCoercion Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c MCoercion Source #

toConstr :: MCoercion -> Constr Source #

dataTypeOf :: MCoercion -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c MCoercion) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c MCoercion) Source #

gmapT :: (forall b. Data b => b -> b) -> MCoercion -> MCoercion Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> MCoercion -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> MCoercion -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> MCoercion -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> MCoercion -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> MCoercion -> m MCoercion Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> MCoercion -> m MCoercion Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> MCoercion -> m MCoercion Source #

Outputable MCoercion Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Methods

ppr :: MCoercion -> SDoc Source #

data CoSel Source #

Instances

Instances details
Data CoSel Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> CoSel -> c CoSel Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c CoSel Source #

toConstr :: CoSel -> Constr Source #

dataTypeOf :: CoSel -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c CoSel) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c CoSel) Source #

gmapT :: (forall b. Data b => b -> b) -> CoSel -> CoSel Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> CoSel -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> CoSel -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> CoSel -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> CoSel -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> CoSel -> m CoSel Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> CoSel -> m CoSel Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> CoSel -> m CoSel Source #

NFData CoSel Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Methods

rnf :: CoSel -> () Source #

Binary CoSel Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Outputable CoSel Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Methods

ppr :: CoSel -> SDoc Source #

Eq CoSel Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Methods

(==) :: CoSel -> CoSel -> Bool #

(/=) :: CoSel -> CoSel -> Bool #

data FunSel Source #

Constructors

SelMult 
SelArg 
SelRes 

Instances

Instances details
Data FunSel Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> FunSel -> c FunSel Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c FunSel Source #

toConstr :: FunSel -> Constr Source #

dataTypeOf :: FunSel -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c FunSel) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c FunSel) Source #

gmapT :: (forall b. Data b => b -> b) -> FunSel -> FunSel Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> FunSel -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> FunSel -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> FunSel -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> FunSel -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> FunSel -> m FunSel Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> FunSel -> m FunSel Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> FunSel -> m FunSel Source #

Outputable FunSel Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Methods

ppr :: FunSel -> SDoc Source #

Eq FunSel Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Methods

(==) :: FunSel -> FunSel -> Bool #

(/=) :: FunSel -> FunSel -> Bool #

data UnivCoProvenance Source #

For simplicity, we have just one UnivCo that represents a coercion from some type to some other type, with (in general) no restrictions on the type. The UnivCoProvenance specifies more exactly what the coercion really is and why a program should (or shouldn't!) trust the coercion. It is reasonable to consider each constructor of UnivCoProvenance as a totally independent coercion form; their only commonality is that they don't tell you what types they coercion between. (That info is in the UnivCo constructor of Coercion.

Instances

Instances details
Data UnivCoProvenance Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> UnivCoProvenance -> c UnivCoProvenance Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c UnivCoProvenance Source #

toConstr :: UnivCoProvenance -> Constr Source #

dataTypeOf :: UnivCoProvenance -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c UnivCoProvenance) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c UnivCoProvenance) Source #

gmapT :: (forall b. Data b => b -> b) -> UnivCoProvenance -> UnivCoProvenance Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> UnivCoProvenance -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> UnivCoProvenance -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> UnivCoProvenance -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> UnivCoProvenance -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> UnivCoProvenance -> m UnivCoProvenance Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> UnivCoProvenance -> m UnivCoProvenance Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> UnivCoProvenance -> m UnivCoProvenance Source #

Outputable UnivCoProvenance Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

data CoercionHole Source #

A coercion to be filled in by the type-checker. See Note [Coercion holes]

Constructors

CoercionHole 

Instances

Instances details
Data CoercionHole Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> CoercionHole -> c CoercionHole Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c CoercionHole Source #

toConstr :: CoercionHole -> Constr Source #

dataTypeOf :: CoercionHole -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c CoercionHole) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c CoercionHole) Source #

gmapT :: (forall b. Data b => b -> b) -> CoercionHole -> CoercionHole Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> CoercionHole -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> CoercionHole -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> CoercionHole -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> CoercionHole -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> CoercionHole -> m CoercionHole Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> CoercionHole -> m CoercionHole Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> CoercionHole -> m CoercionHole Source #

Uniquable CoercionHole Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Outputable CoercionHole Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

data LeftOrRight Source #

Constructors

CLeft 
CRight 

Instances

Instances details
Data LeftOrRight Source # 
Instance details

Defined in GHC.Types.Basic

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> LeftOrRight -> c LeftOrRight Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c LeftOrRight Source #

toConstr :: LeftOrRight -> Constr Source #

dataTypeOf :: LeftOrRight -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c LeftOrRight) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c LeftOrRight) Source #

gmapT :: (forall b. Data b => b -> b) -> LeftOrRight -> LeftOrRight Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> LeftOrRight -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> LeftOrRight -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> LeftOrRight -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> LeftOrRight -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> LeftOrRight -> m LeftOrRight Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> LeftOrRight -> m LeftOrRight Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> LeftOrRight -> m LeftOrRight Source #

Binary LeftOrRight Source # 
Instance details

Defined in GHC.Types.Basic

Outputable LeftOrRight Source # 
Instance details

Defined in GHC.Types.Basic

Methods

ppr :: LeftOrRight -> SDoc Source #

Eq LeftOrRight Source # 
Instance details

Defined in GHC.Types.Basic

type CoVar = Id Source #

Coercion Variable

type TyCoVar = Id Source #

Type or Coercion Variable

type NormaliseStepper ev = RecTcChecker -> TyCon -> [Type] -> NormaliseStepResult ev Source #

A function to check if we can reduce a type by one step. Used with topNormaliseTypeX.

data NormaliseStepResult ev Source #

The result of stepping in a normalisation function. See topNormaliseTypeX.

Constructors

NS_Done

Nothing more to do

NS_Abort

Utter failure. The outer function should fail too.

NS_Step RecTcChecker Type ev

We stepped, yielding new bits; ^ ev is evidence; Usually a co :: old type ~ new type

Instances

Instances details
Functor NormaliseStepResult Source # 
Instance details

Defined in GHC.Core.Coercion

Outputable ev => Outputable (NormaliseStepResult ev) Source # 
Instance details

Defined in GHC.Core.Coercion

type CvSubstEnv = CoVarEnv Coercion Source #

A substitution of Coercions for CoVars

data LiftingContext Source #

Constructors

LC Subst LiftCoEnv 

Instances

Instances details
Outputable LiftingContext Source # 
Instance details

Defined in GHC.Core.Coercion

mkCoercionType :: Role -> Type -> Type -> Type Source #

Makes a coercion type from two types: the types whose equality is proven by the relevant Coercion

coercionKind :: Coercion -> Pair Type Source #

If it is the case that

c :: (t1 ~ t2)

i.e. the kind of c relates t1 and t2, then coercionKind c = Pair t1 t2.

coercionRole :: Coercion -> Role Source #

Retrieve the role from a coercion.

coercionKindRole :: Coercion -> (Pair Type, Role) Source #

Get a coercion's kind and role.

mkGReflCo :: Role -> Type -> MCoercionN -> Coercion Source #

Make a generalized reflexive coercion

mkReflCo :: Role -> Type -> Coercion Source #

Make a reflexive coercion

mkRepReflCo :: Type -> Coercion Source #

Make a representational reflexive coercion

mkNomReflCo :: Type -> Coercion Source #

Make a nominal reflexive coercion

mkAxInstLHS :: CoAxiom br -> BranchIndex -> [Type] -> [Coercion] -> Type Source #

Return the left-hand type of the axiom, when the axiom is instantiated at the types given.

mkUnbranchedAxInstLHS :: CoAxiom Unbranched -> [Type] -> [Coercion] -> Type Source #

Instantiate the left-hand side of an unbranched axiom

mkPiCo :: Role -> Var -> Coercion -> Coercion Source #

Make a forall Coercion, where both types related by the coercion are quantified over the same variable.

mkSymCo :: Coercion -> Coercion Source #

Create a symmetric version of the given Coercion that asserts equality between the same types but in the other "direction", so a kind of t1 ~ t2 becomes the kind t2 ~ t1.

mkTransCo :: Coercion -> Coercion -> Coercion Source #

Create a new Coercion by composing the two given Coercions transitively. (co1 ; co2)

getNthFun Source #

Arguments

:: FunSel 
-> a

multiplicity

-> a

argument

-> a

result

-> a

One of the above three

Extract the nth field of a FunCo

mkAppCo Source #

Arguments

:: Coercion

:: t1 ~r t2

-> Coercion

:: s1 ~N s2, where s1 :: k1, s2 :: k2

-> Coercion

:: t1 s1 ~r t2 s2

Apply a Coercion to another Coercion. The second coercion must be Nominal, unless the first is Phantom. If the first is Phantom, then the second can be either Phantom or Nominal.

mkAppCos :: Coercion -> [Coercion] -> Coercion Source #

Applies multiple Coercions to another Coercion, from left to right. See also mkAppCo.

mkTyConAppCo :: HasDebugCallStack => Role -> TyCon -> [Coercion] -> Coercion Source #

Apply a type constructor to a list of coercions. It is the caller's responsibility to get the roles correct on argument coercions.

mkFunCo1 :: HasDebugCallStack => Role -> FunTyFlag -> CoercionN -> Coercion -> Coercion -> Coercion Source #

Build a function Coercion from two other Coercions. That is, given co1 :: a ~ b and co2 :: x ~ y produce co :: (a -> x) ~ (b -> y) or (a => x) ~ (b => y), depending on the kind of a/b. This (most common) version takes a single FunTyFlag, which is used for both fco_afl and ftf_afr of the FunCo

mkForAllCo :: TyCoVar -> CoercionN -> Coercion -> Coercion Source #

Make a Coercion from a tycovar, a kind coercion, and a body coercion. The kind of the tycovar should be the left-hand kind of the kind coercion. See Note [Unused coercion variable in ForAllCo]

mkForAllCos :: [(TyCoVar, CoercionN)] -> Coercion -> Coercion Source #

Make nested ForAllCos

mkHomoForAllCos :: [TyCoVar] -> Coercion -> Coercion Source #

Make a Coercion quantified over a type/coercion variable; the variable has the same type in both sides of the coercion

mkPhantomCo :: Coercion -> Type -> Type -> Coercion Source #

Make a phantom coercion between two types. The coercion passed in must be a nominal coercion between the kinds of the types.

mkHoleCo :: CoercionHole -> Coercion Source #

Make a coercion from a coercion hole

mkUnivCo Source #

Arguments

:: UnivCoProvenance 
-> Role

role of the built coercion, "r"

-> Type

t1 :: k1

-> Type

t2 :: k2

-> Coercion

:: t1 ~r t2

Make a universal coercion between two arbitrary types.

mkProofIrrelCo Source #

Arguments

:: Role

role of the created coercion, "r"

-> CoercionN

:: phi1 ~N phi2

-> Coercion

g1 :: phi1

-> Coercion

g2 :: phi2

-> Coercion

:: g1 ~r g2

Make a "coercion between coercions".

downgradeRole :: Role -> Role -> Coercion -> Coercion Source #

Like downgradeRole_maybe, but panics if the change isn't a downgrade. See Note [Role twiddling functions]

mkGReflRightCo :: Role -> Type -> CoercionN -> Coercion Source #

Given ty :: k1, co :: k1 ~ k2, produces co' :: ty ~r (ty |> co)

mkGReflLeftCo :: Role -> Type -> CoercionN -> Coercion Source #

Given r, ty :: k1, and co :: k1 ~N k2, produces co' :: (ty |> co) ~r ty

mkCoherenceLeftCo :: Role -> Type -> CoercionN -> Coercion -> Coercion Source #

Given ty :: k1, co :: k1 ~ k2, co2:: ty ~r ty', produces @co' :: (ty |> co) ~r ty' It is not only a utility function, but it saves allocation when co is a GRefl coercion.

mkCoherenceRightCo :: Role -> Type -> CoercionN -> Coercion -> Coercion Source #

Given ty :: k1, co :: k1 ~ k2, co2:: ty' ~r ty, produces @co' :: ty' ~r (ty |> co) It is not only a utility function, but it saves allocation when co is a GRefl coercion.

mkKindCo :: Coercion -> Coercion Source #

Given co :: (a :: k) ~ (b :: k') produce co' :: k ~ k'.

castCoercionKind :: Coercion -> CoercionN -> CoercionN -> Coercion Source #

Creates a new coercion with both of its types casted by different casts castCoercionKind g h1 h2, where g :: t1 ~r t2, has type (t1 |> h1) ~r (t2 |> h2). h1 and h2 must be nominal. It calls coercionKindRole, so it's quite inefficient (which I stands for) Use castCoercionKind2 instead if t1, t2, and r are known beforehand.

castCoercionKind1 :: Coercion -> Role -> Type -> Type -> CoercionN -> Coercion Source #

castCoercionKind1 g r t1 t2 h = coercionKind g r t1 t2 h h That is, it's a specialised form of castCoercionKind, where the two kind coercions are identical castCoercionKind1 g r t1 t2 h, where g :: t1 ~r t2, has type (t1 |> h) ~r (t2 |> h). h must be nominal. See Note [castCoercionKind1]

castCoercionKind2 :: Coercion -> Role -> Type -> Type -> CoercionN -> CoercionN -> Coercion Source #

Creates a new coercion with both of its types casted by different casts castCoercionKind2 g r t1 t2 h1 h2, where g :: t1 ~r t2, has type (t1 |> h1) ~r (t2 |> h2). h1 and h2 must be nominal.

mkPrimEqPred :: Type -> Type -> Type Source #

Creates a primitive type equality predicate. Invariant: the types are not Coercions

mkPrimEqPredRole :: Role -> Type -> Type -> PredType Source #

Makes a lifted equality predicate at the given role

mkHeteroPrimEqPred :: Kind -> Kind -> Type -> Type -> Type Source #

Creates a primitive type equality predicate with explicit kinds

mkHeteroReprPrimEqPred :: Kind -> Kind -> Type -> Type -> Type Source #

Creates a primitive representational type equality predicate with explicit kinds

instNewTyCon_maybe :: TyCon -> [Type] -> Maybe (Type, Coercion) Source #

If `instNewTyCon_maybe T ts = Just (rep_ty, co)` then `co :: T ts ~R# rep_ty`

Checks for a newtype, and for being saturated

composeSteppers :: NormaliseStepper ev -> NormaliseStepper ev -> NormaliseStepper ev Source #

Try one stepper and then try the next, if the first doesn't make progress. So if it returns NS_Done, it means that both steppers are satisfied

unwrapNewTypeStepper :: NormaliseStepper Coercion Source #

A NormaliseStepper that unwraps newtypes, careful not to fall into a loop. If it would fall into a loop, it produces NS_Abort.

topNormaliseNewType_maybe :: Type -> Maybe (Coercion, Type) Source #

Sometimes we want to look through a newtype and get its associated coercion. This function strips off newtype layers enough to reveal something that isn't a newtype. Specifically, here's the invariant:

topNormaliseNewType_maybe rec_nts ty = Just (co, ty')

then (a) co : ty ~R ty'. (b) ty' is not a newtype.

The function returns Nothing for non-newtypes, or unsaturated applications

This function does *not* look through type families, because it has no access to the type family environment. If you do have that at hand, consider to use topNormaliseType_maybe, which should be a drop-in replacement for topNormaliseNewType_maybe If topNormliseNewType_maybe ty = Just (co, ty'), then co : ty ~R ty'

topNormaliseTypeX :: NormaliseStepper ev -> (ev -> ev -> ev) -> Type -> Maybe (ev, Type) Source #

A general function for normalising the top-level of a type. It continues to use the provided NormaliseStepper until that function fails, and then this function returns. The roles of the coercions produced by the NormaliseStepper must all be the same, which is the role returned from the call to topNormaliseTypeX.

Typically ev is Coercion.

If topNormaliseTypeX step plus ty = Just (ev, ty') then ty ~ev1~ t1 ~ev2~ t2 ... ~evn~ ty' and ev = ev1 plus ev2 plus ... plus evn If it returns Nothing then no newtype unwrapping could happen

decomposeCo :: Arity -> Coercion -> Infinite Role -> [Coercion] Source #

This breaks a Coercion with type T A B C ~ T D E F into a list of Coercions of kinds A ~ D, B ~ E and E ~ F. Hence:

decomposeCo 3 c [r1, r2, r3] = [nth r1 0 c, nth r2 1 c, nth r3 2 c]

getCoVar_maybe :: Coercion -> Maybe CoVar Source #

Extract a covar, if possible. This check is dirty. Be ashamed of yourself. (It's dirty because it cares about the structure of a coercion, which is morally reprehensible.)

splitAppCo_maybe :: Coercion -> Maybe (Coercion, Coercion) Source #

Attempt to take a coercion application apart.

splitForAllCo_ty_maybe :: Coercion -> Maybe (TyVar, Coercion, Coercion) Source #

Like splitForAllCo_maybe, but only returns Just for tyvar binder

splitForAllCo_co_maybe :: Coercion -> Maybe (CoVar, Coercion, Coercion) Source #

Like splitForAllCo_maybe, but only returns Just for covar binder

setNominalRole_maybe :: Role -> Coercion -> Maybe CoercionN Source #

Converts a coercion to be nominal, if possible. See Note [Role twiddling functions]

pickLR :: LeftOrRight -> (a, a) -> a Source #

isGReflCo :: Coercion -> Bool Source #

Tests if this coercion is obviously a generalized reflexive coercion. Guaranteed to work very quickly.

isReflCo :: Coercion -> Bool Source #

Tests if this coercion is obviously reflexive. Guaranteed to work very quickly. Sometimes a coercion can be reflexive, but not obviously so. c.f. isReflexiveCo

isReflCo_maybe :: Coercion -> Maybe (Type, Role) Source #

Returns the type coerced if this coercion is reflexive. Guaranteed to work very quickly. Sometimes a coercion can be reflexive, but not obviously so. c.f. isReflexiveCo_maybe

isGReflCo_maybe :: Coercion -> Maybe (Type, Role) Source #

Returns the type coerced if this coercion is a generalized reflexive coercion. Guaranteed to work very quickly.

isReflexiveCo :: Coercion -> Bool Source #

Slowly checks if the coercion is reflexive. Don't call this in a loop, as it walks over the entire coercion.

isReflexiveCo_maybe :: Coercion -> Maybe (Type, Role) Source #

Extracts the coerced type from a reflexive coercion. This potentially walks over the entire coercion, so avoid doing this in a loop.

isGReflMCo :: MCoercion -> Bool Source #

Tests if this MCoercion is obviously generalized reflexive Guaranteed to work very quickly.

mkTransMCo :: MCoercion -> MCoercion -> MCoercion Source #

Compose two MCoercions via transitivity

mkCastTyMCo :: Type -> MCoercion -> Type Source #

Cast a type by an MCoercion

mkSymMCo :: MCoercion -> MCoercion Source #

Get the reverse of an MCoercion

isCoVar :: Var -> Bool Source #

Is this a coercion variable? Satisfies isId v ==> isCoVar v == not (isNonCoVarId v).

tyCoVarsOfCoDSet :: Coercion -> DTyCoVarSet Source #

Get a deterministic set of the vars free in a coercion

substCos :: HasDebugCallStack => Subst -> [Coercion] -> [Coercion] Source #

Substitute within several Coercions The substitution has to satisfy the invariants described in Note [The substitution invariant].

substCoWith :: HasDebugCallStack => [TyVar] -> [Type] -> Coercion -> Coercion Source #

Coercion substitution, see zipTvSubst

liftCoSubst :: HasDebugCallStack => Role -> LiftingContext -> Type -> Coercion Source #

liftCoSubst role lc ty produces a coercion (at role role) that coerces between lc_left(ty) and lc_right(ty), where lc_left is a substitution mapping type variables to the left-hand types of the mapped coercions in lc, and similar for lc_right.

extendLiftingContext Source #

Arguments

:: LiftingContext

original LC

-> TyCoVar

new variable to map...

-> Coercion

...to this lifted version

-> LiftingContext 

Extend a lifting context with a new mapping.

extendLiftingContextAndInScope Source #

Arguments

:: LiftingContext

Original LC

-> TyCoVar

new variable to map...

-> Coercion

to this coercion

-> LiftingContext 

Extend a lifting context with a new mapping, and extend the in-scope set

liftCoSubstVarBndrUsing Source #

Arguments

:: (r -> CoercionN)

coercion getter

-> (LiftingContext -> Type -> r)

callback

-> LiftingContext 
-> TyCoVar 
-> (LiftingContext, TyCoVar, r) 

isMappedByLC :: TyCoVar -> LiftingContext -> Bool Source #

Is a var in the domain of a lifting context?

zapLiftingContext :: LiftingContext -> LiftingContext Source #

Erase the environments in a lifting context

lcSubst :: LiftingContext -> Subst Source #

Extract the underlying substitution from the LiftingContext

swapLiftCoEnv :: LiftCoEnv -> LiftCoEnv Source #

Apply "sym" to all coercions in a LiftCoEnv

eqCoercion :: Coercion -> Coercion -> Bool Source #

Syntactic equality of coercions

eqCoercionX :: RnEnv2 -> Coercion -> Coercion -> Bool Source #

Compare two Coercions, with respect to an RnEnv2

tidyCo :: TidyEnv -> Coercion -> Coercion Source #

Tidy a Coercion

See Note [Strictness in tidyType and friends]

promoteCoercion :: Coercion -> CoercionN Source #

like mkKindCo, but aggressively & recursively optimizes to avoid using a KindCo constructor. The output role is nominal.

buildCoercion :: Type -> Type -> CoercionN Source #

Assuming that two types are the same, ignoring coercions, find a nominal coercion between the types. This is useful when optimizing transitivity over coercion applications, where splitting two AppCos might yield different kinds. See Note [EtaAppCo] in GHC.Core.Coercion.Opt.

mkRuntimeRepCo :: HasDebugCallStack => Coercion -> Coercion Source #

Given a coercion `co :: (t1 :: TYPE r1) ~ (t2 :: TYPE r2)` produce a coercion `rep_co :: r1 ~ r2` But actually it is possible that co :: (t1 :: CONSTRAINT r1) ~ (t2 :: CONSTRAINT r2) or co :: (t1 :: TYPE r1) ~ (t2 :: CONSTRAINT r2) or co :: (t1 :: CONSTRAINT r1) ~ (t2 :: TYPE r2) See Note [mkRuntimeRepCo]

hasCoercionHoleTy :: Type -> Bool Source #

Is there a coercion hole in this type?

hasCoercionHoleCo :: Coercion -> Bool Source #

Is there a coercion hole in this coercion?

data Unique Source #

Unique identifier.

The type of unique identifiers that are used in many places in GHC for fast ordering and equality tests. You should generate these with the functions from the UniqSupply module

These are sometimes also referred to as "keys" in comments in GHC.

Instances

Instances details
Show Unique Source # 
Instance details

Defined in GHC.Types.Unique

Uniquable Unique Source # 
Instance details

Defined in GHC.Types.Unique

Outputable Unique Source # 
Instance details

Defined in GHC.Types.Unique

Methods

ppr :: Unique -> SDoc Source #

Eq Unique Source # 
Instance details

Defined in GHC.Types.Unique

Methods

(==) :: Unique -> Unique -> Bool #

(/=) :: Unique -> Unique -> Bool #

class Uniquable a where Source #

Class of things that we can obtain a Unique from

Methods

getUnique :: a -> Unique Source #

Instances

Instances details
Uniquable Label Source # 
Instance details

Defined in GHC.Cmm.Dataflow.Label

Uniquable LocalReg Source # 
Instance details

Defined in GHC.Cmm.Reg

Uniquable Reg Source #

so we can put regs in UniqSets

Instance details

Defined in GHC.CmmToAsm.Reg.Graph.Base

Methods

getUnique :: Reg -> Unique Source #

Uniquable SymName Source # 
Instance details

Defined in GHC.CmmToAsm.Wasm.Types

Uniquable Class Source # 
Instance details

Defined in GHC.Core.Class

Uniquable CoAxiomRule Source # 
Instance details

Defined in GHC.Core.Coercion.Axiom

Uniquable ConLike Source # 
Instance details

Defined in GHC.Core.ConLike

Uniquable DataCon Source # 
Instance details

Defined in GHC.Core.DataCon

Uniquable PatSyn Source # 
Instance details

Defined in GHC.Core.PatSyn

Uniquable CoercionHole Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Uniquable TyCon Source # 
Instance details

Defined in GHC.Core.TyCon

Uniquable FastString Source # 
Instance details

Defined in GHC.Types.Unique

Uniquable Ident Source # 
Instance details

Defined in GHC.JS.Syntax

Uniquable RealReg Source # 
Instance details

Defined in GHC.Platform.Reg

Uniquable Reg Source # 
Instance details

Defined in GHC.Platform.Reg

Methods

getUnique :: Reg -> Unique Source #

Uniquable VirtualReg Source # 
Instance details

Defined in GHC.Platform.Reg

Uniquable RegClass Source # 
Instance details

Defined in GHC.Platform.Reg.Class

Uniquable EvBindsVar Source # 
Instance details

Defined in GHC.Tc.Types.Evidence

Uniquable SkolemInfo Source # 
Instance details

Defined in GHC.Tc.Types.Origin

Uniquable Name Source # 
Instance details

Defined in GHC.Types.Name

Uniquable OccName Source # 
Instance details

Defined in GHC.Types.Name.Occurrence

Uniquable Unique Source # 
Instance details

Defined in GHC.Types.Unique

Uniquable Var Source # 
Instance details

Defined in GHC.Types.Var

Methods

getUnique :: Var -> Unique Source #

Uniquable PackageId Source # 
Instance details

Defined in GHC.Unit.Info

Uniquable PackageName Source # 
Instance details

Defined in GHC.Unit.Info

Uniquable Module Source # 
Instance details

Defined in GHC.Unit.Types

Uniquable UnitId Source # 
Instance details

Defined in GHC.Unit.Types

Uniquable FieldLabelString Source # 
Instance details

Defined in GHC.Types.FieldLabel

Uniquable ModuleName Source # 
Instance details

Defined in GHC.Types.Unique

Uniquable Int Source # 
Instance details

Defined in GHC.Types.Unique

Methods

getUnique :: Int -> Unique Source #

Uniquable (CoAxiom br) Source # 
Instance details

Defined in GHC.Core.Coercion.Axiom

Methods

getUnique :: CoAxiom br -> Unique Source #

Uniquable unit => Uniquable (Definite unit) Source # 
Instance details

Defined in GHC.Unit.Types

Methods

getUnique :: Definite unit -> Unique Source #

IsUnitId u => Uniquable (GenUnit u) Source # 
Instance details

Defined in GHC.Unit.Types

data Messages e Source #

A collection of messages emitted by GHC during error reporting. A diagnostic message is typically a warning or an error. See Note [Messages].

INVARIANT: All the messages in this collection must be relevant, i.e. their Severity should not be SevIgnore. The smart constructor mkMessages will filter out any message which Severity is SevIgnore.

Instances

Instances details
Foldable Messages Source # 
Instance details

Defined in GHC.Types.Error

Methods

fold :: Monoid m => Messages m -> m Source #

foldMap :: Monoid m => (a -> m) -> Messages a -> m Source #

foldMap' :: Monoid m => (a -> m) -> Messages a -> m Source #

foldr :: (a -> b -> b) -> b -> Messages a -> b Source #

foldr' :: (a -> b -> b) -> b -> Messages a -> b Source #

foldl :: (b -> a -> b) -> b -> Messages a -> b Source #

foldl' :: (b -> a -> b) -> b -> Messages a -> b Source #

foldr1 :: (a -> a -> a) -> Messages a -> a Source #

foldl1 :: (a -> a -> a) -> Messages a -> a Source #

toList :: Messages a -> [a] Source #

null :: Messages a -> Bool Source #

length :: Messages a -> Int Source #

elem :: Eq a => a -> Messages a -> Bool Source #

maximum :: Ord a => Messages a -> a Source #

minimum :: Ord a => Messages a -> a Source #

sum :: Num a => Messages a -> a Source #

product :: Num a => Messages a -> a Source #

Traversable Messages Source # 
Instance details

Defined in GHC.Types.Error

Methods

traverse :: Applicative f => (a -> f b) -> Messages a -> f (Messages b) Source #

sequenceA :: Applicative f => Messages (f a) -> f (Messages a) Source #

mapM :: Monad m => (a -> m b) -> Messages a -> m (Messages b) Source #

sequence :: Monad m => Messages (m a) -> m (Messages a) Source #

Functor Messages Source # 
Instance details

Defined in GHC.Types.Error

Methods

fmap :: (a -> b) -> Messages a -> Messages b Source #

(<$) :: a -> Messages b -> Messages a Source #

Monoid (Messages e) Source # 
Instance details

Defined in GHC.Types.Error

Semigroup (Messages e) Source # 
Instance details

Defined in GHC.Types.Error

Diagnostic e => Outputable (Messages e) Source # 
Instance details

Defined in GHC.Types.Error

Methods

ppr :: Messages e -> SDoc Source #

Getting Names

thNameToGhcName :: Name -> CoreM (Maybe Name) Source #

Attempt to convert a Template Haskell name to one that GHC can understand. Original TH names such as those you get when you use the 'foo syntax will be translated to their equivalent GHC name exactly. Qualified or unqualified TH names will be dynamically bound to names in the module being compiled, if possible. Exact TH names will be bound to the name they represent, exactly.

thNameToGhcNameIO :: NameCache -> Name -> IO (Maybe Name) Source #

Attempt to convert a Template Haskell name to one that GHC can understand. Original TH names such as those you get when you use the 'foo syntax will be translated to their equivalent GHC name exactly. Qualified or unqualified TH names will be dynamically bound to names in the module being compiled, if possible. Exact TH names will be bound to the name they represent, exactly.

One must be careful to consistently use the same NameCache to create identifier that might be compared. (C.f. how the ST Monad enforces that variables from separate runST invocations are never intermingled; it would be valid to use the same tricks for Names and NameCaches.)

For now, the easiest and recommended way to ensure a consistent NameCache is used it to retrieve the preexisting one from an active HscEnv. A single HscEnv is created per GHC "session", and this ensures everything in that session will get the same name cache.

Orphan instances