GHC.Core.TyCo.FVs

Documentation

shallowTyCoVarsOfType :: Type -> TyCoVarSet

shallowTyCoVarsOfTypes :: [Type] -> TyCoVarSet

tyCoVarsOfType :: Type -> TyCoVarSet

tyCoVarsOfTypes :: [Type] -> TyCoVarSet

tyCoVarsOfTypeDSet :: Type -> DTyCoVarSet

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.

tyCoVarsOfTypesDSet :: [Type] -> DTyCoVarSet

Returns free variables of types, including kind variables as a deterministic set. For type synonyms it does not expand the synonym.

tyCoFVsBndr :: ForAllTyBinder -> FV -> FV

tyCoFVsVarBndr :: Var -> FV -> FV

tyCoFVsVarBndrs :: [Var] -> FV -> FV

tyCoFVsOfType :: Type -> FV

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.

tyCoVarsOfTypeList :: Type -> [TyCoVar]

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

tyCoFVsOfTypes :: [Type] -> FV

tyCoVarsOfTypesList :: [Type] -> [TyCoVar]

Returns free variables of types, including kind variables as a deterministically ordered list. For type synonyms it does not expand the synonym.

deepTcvFolder :: TyCoFolder TyCoVarSet (Endo TyCoVarSet)

shallowTyCoVarsOfTyVarEnv :: TyVarEnv Type -> TyCoVarSet

Returns free variables of types, including kind variables as a non-deterministic set. For type synonyms it does not expand the synonym.

shallowTyCoVarsOfCoVarEnv :: CoVarEnv Coercion -> TyCoVarSet

shallowTyCoVarsOfCo :: Coercion -> TyCoVarSet

shallowTyCoVarsOfCos :: [Coercion] -> TyCoVarSet

tyCoVarsOfCo :: Coercion -> TyCoVarSet

tyCoVarsOfCos :: [Coercion] -> TyCoVarSet

tyCoVarsOfMCo :: MCoercion -> TyCoVarSet

coVarsOfType :: Type -> CoVarSet

coVarsOfTypes :: [Type] -> CoVarSet

coVarsOfCo :: Coercion -> CoVarSet

coVarsOfCos :: [Coercion] -> CoVarSet

tyCoVarsOfCoDSet :: Coercion -> DTyCoVarSet

Get a deterministic set of the vars free in a coercion

tyCoFVsOfCo :: Coercion -> FV

tyCoFVsOfCos :: [Coercion] -> FV

tyCoVarsOfCoList :: Coercion -> [TyCoVar]

almostDevoidCoVarOfCo :: CoVar -> Coercion -> Bool

Given a covar and a coercion, returns True if covar is almost devoid in the coercion. That is, covar can only appear in Refl and GRefl. See last wrinkle in Note [Unused coercion variable in ForAllCo] in GHC.Core.Coercion

injectiveVarsOfType

Arguments

:: Bool

Should we look under injective type families? See Note [Coverage condition for injective type families] in GHC.Tc.Instance.Family.

-> Type

-> FV

Returns the free variables of a Type that are in injective positions. Specifically, it finds the free variables while:

• Expanding type synonyms
• Ignoring the coercion in (ty |> co)
• Ignoring the non-injective fields of a TyConApp

For example, if F is a non-injective type family, then:

injectiveTyVarsOf( Either c (Maybe (a, F b c)) ) = {a,c}

If injectiveVarsOfType ty = itvs, then knowing ty fixes itvs. More formally, if a is in injectiveVarsOfType ty and S1(ty) ~ S2(ty), then S1(a) ~ S2(a), where S1 and S2 are arbitrary substitutions.

See Note [When does a tycon application need an explicit kind signature?].

injectiveVarsOfTypes

Arguments

:: Bool

look under injective type families? See Note [Coverage condition for injective type families] in GHC.Tc.Instance.Family.

-> [Type]

-> FV

Returns the free variables of a Type that are in injective positions. Specifically, it finds the free variables while:

• Expanding type synonyms
• Ignoring the coercion in (ty |> co)
• Ignoring the non-injective fields of a TyConApp

See Note [When does a tycon application need an explicit kind signature?].

invisibleVarsOfType :: Type -> FV

Returns the set of variables that are used invisibly anywhere within the given type. A variable will be included even if it is used both visibly and invisibly. An invisible use site includes: * In the kind of a variable * In the kind of a bound variable in a forall * In a coercion * In a Specified or Inferred argument to a function See Note [VarBndrs, ForAllTyBinders, TyConBinders, and visibility] in GHC.Core.TyCo.Rep

invisibleVarsOfTypes :: [Type] -> FV

Like invisibleVarsOfType, but for many types.

anyFreeVarsOfType :: (TyCoVar -> Bool) -> Type -> Bool

anyFreeVarsOfTypes :: (TyCoVar -> Bool) -> [Type] -> Bool

anyFreeVarsOfCo :: (TyCoVar -> Bool) -> Coercion -> Bool

noFreeVarsOfType :: Type -> Bool

noFreeVarsOfTypes :: [Type] -> Bool

noFreeVarsOfCo :: Coercion -> Bool

Free type constructors

tyConsOfType :: Type -> UniqSet TyCon

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

tyConsOfTypes :: [Type] -> UniqSet TyCon

Free vars with visible/invisible separate

visVarsOfTypes :: [Type] -> Pair TyCoVarSet

visVarsOfType :: Type -> Pair TyCoVarSet

Retrieve the free variables in this type, splitting them based on whether they are used visibly or invisibly. Invisible ones come first.

Occurrence-check expansion

occCheckExpand :: [Var] -> Type -> Maybe Type

Well-scoped free variables

scopedSort :: [TyCoVar] -> [TyCoVar]

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]

Get the free vars of a type in scoped order

tyCoVarsOfTypesWellScoped :: [Type] -> [TyVar]

Get the free vars of types in scoped order

Closing over kinds

closeOverKindsDSet :: DTyVarSet -> DTyVarSet

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

closeOverKindsList :: [TyVar] -> [TyVar]

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

closeOverKinds :: TyCoVarSet -> TyCoVarSet

Raw materials

newtype Endo a

The monoid of endomorphisms under composition.

>>> let computation = Endo ("Hello, " ++) <> Endo (++ "!")
>>> appEndo computation "Haskell"
"Hello, Haskell!"

Constructors

Endo

Fields

• appEndo :: a -> a

Instances

Monoid (Endo a)

Since: base-2.1

Defined in Data.Semigroup.Internal

Methods

mempty :: Endo a

mappend :: Endo a -> Endo a -> Endo a

mconcat :: [Endo a] -> Endo a

Semigroup (Endo a)

Since: base-4.9.0.0

Defined in Data.Semigroup.Internal

Methods

(<>) :: Endo a -> Endo a -> Endo a

sconcat :: NonEmpty (Endo a) -> Endo a

stimes :: Integral b => b -> Endo a -> Endo a

Generic (Endo a)

Defined in Data.Semigroup.Internal

Associated Types

type Rep (Endo a) :: Type -> Type

Methods

from :: Endo a -> Rep (Endo a) x

to :: Rep (Endo a) x -> Endo a

type Rep (Endo a)

Since: base-4.7.0.0

Defined in Data.Semigroup.Internal

type Rep (Endo a) = D1 ('MetaData "Endo" "Data.Semigroup.Internal" "base" 'True) (C1 ('MetaCons "Endo" 'PrefixI 'True) (S1 ('MetaSel ('Just "appEndo") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (a -> a))))

runTyCoVars :: Endo TyCoVarSet -> TyCoVarSet