ghc-lib-parser-9.12.2.20250421: The GHC API, decoupled from GHC versions

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GHC.Core.TyCo.Subst

Contents

- Substitutions

Description

Substitution into types and coercions.

Synopsis

- data Subst = Subst InScopeSet IdSubstEnv TvSubstEnv CvSubstEnv
- type TvSubstEnv = TyVarEnv Type
- type CvSubstEnv = CoVarEnv Coercion
- type IdSubstEnv = IdEnv CoreExpr
- emptyIdSubstEnv :: IdSubstEnv
- emptyTvSubstEnv :: TvSubstEnv
- emptyCvSubstEnv :: CvSubstEnv
- composeTCvSubst :: Subst -> Subst -> Subst
- emptySubst :: Subst
- mkEmptySubst :: InScopeSet -> Subst
- isEmptyTCvSubst :: Subst -> Bool
- isEmptySubst :: Subst -> Bool
- mkTCvSubst :: InScopeSet -> TvSubstEnv -> CvSubstEnv -> Subst
- mkTvSubst :: InScopeSet -> TvSubstEnv -> Subst
- mkCvSubst :: InScopeSet -> CvSubstEnv -> Subst
- mkIdSubst :: InScopeSet -> IdSubstEnv -> Subst
- getTvSubstEnv :: Subst -> TvSubstEnv
- getIdSubstEnv :: Subst -> IdSubstEnv
- getCvSubstEnv :: Subst -> CvSubstEnv
- getSubstInScope :: Subst -> InScopeSet
- setInScope :: Subst -> InScopeSet -> Subst
- getSubstRangeTyCoFVs :: Subst -> VarSet
- isInScope :: Var -> Subst -> Bool
- elemSubst :: Var -> Subst -> Bool
- notElemSubst :: Var -> Subst -> Bool
- zapSubst :: Subst -> Subst
- extendSubstInScope :: Subst -> Var -> Subst
- extendSubstInScopeList :: Subst -> [Var] -> Subst
- extendSubstInScopeSet :: Subst -> VarSet -> Subst
- extendTCvSubst :: Subst -> TyCoVar -> Type -> Subst
- extendTCvSubstWithClone :: Subst -> TyCoVar -> TyCoVar -> Subst
- extendCvSubst :: Subst -> CoVar -> Coercion -> Subst
- extendCvSubstWithClone :: Subst -> CoVar -> CoVar -> Subst
- extendTvSubst :: Subst -> TyVar -> Type -> Subst
- extendTvSubstWithClone :: Subst -> TyVar -> TyVar -> Subst
- extendTvSubstList :: Subst -> [(TyVar, Type)] -> Subst
- extendTvSubstAndInScope :: Subst -> TyVar -> Type -> Subst
- extendTCvSubstList :: Subst -> [Var] -> [Type] -> Subst
- unionSubst :: Subst -> Subst -> Subst
- zipTyEnv :: HasDebugCallStack => [TyVar] -> [Type] -> TvSubstEnv
- zipCoEnv :: HasDebugCallStack => [CoVar] -> [Coercion] -> CvSubstEnv
- zipTvSubst :: HasDebugCallStack => [TyVar] -> [Type] -> Subst
- zipCvSubst :: HasDebugCallStack => [CoVar] -> [Coercion] -> Subst
- zipTCvSubst :: HasDebugCallStack => [TyCoVar] -> [Type] -> Subst
- mkTvSubstPrs :: [(TyVar, Type)] -> Subst
- substTyWith :: HasDebugCallStack => [TyVar] -> [Type] -> Type -> Type
- substTyWithCoVars :: [CoVar] -> [Coercion] -> Type -> Type
- substTysWith :: HasDebugCallStack => [TyVar] -> [Type] -> [Type] -> [Type]
- substTysWithCoVars :: HasDebugCallStack => [CoVar] -> [Coercion] -> [Type] -> [Type]
- substCoWith :: HasDebugCallStack => [TyVar] -> [Type] -> Coercion -> Coercion
- substTy :: HasDebugCallStack => Subst -> Type -> Type
- substTyAddInScope :: HasDebugCallStack => Subst -> Type -> Type
- substScaledTy :: HasDebugCallStack => Subst -> Scaled Type -> Scaled Type
- substTyUnchecked :: Subst -> Type -> Type
- substTysUnchecked :: Subst -> [Type] -> [Type]
- substScaledTysUnchecked :: Subst -> [Scaled Type] -> [Scaled Type]
- substThetaUnchecked :: Subst -> ThetaType -> ThetaType
- substTyWithUnchecked :: [TyVar] -> [Type] -> Type -> Type
- substScaledTyUnchecked :: HasDebugCallStack => Subst -> Scaled Type -> Scaled Type
- substCoUnchecked :: Subst -> Coercion -> Coercion
- substCoWithUnchecked :: [TyVar] -> [Type] -> Coercion -> Coercion
- substTyWithInScope :: HasDebugCallStack => InScopeSet -> [TyVar] -> [Type] -> Type -> Type
- substTys :: HasDebugCallStack => Subst -> [Type] -> [Type]
- substScaledTys :: HasDebugCallStack => Subst -> [Scaled Type] -> [Scaled Type]
- substTheta :: HasDebugCallStack => Subst -> ThetaType -> ThetaType
- lookupTyVar :: Subst -> TyVar -> Maybe Type
- substCo :: HasDebugCallStack => Subst -> Coercion -> Coercion
- substCos :: HasDebugCallStack => Subst -> [Coercion] -> [Coercion]
- substCoVar :: Subst -> CoVar -> Coercion
- substCoVars :: Subst -> [CoVar] -> [Coercion]
- lookupCoVar :: Subst -> Var -> Maybe Coercion
- cloneTyVarBndr :: Subst -> TyVar -> Unique -> (Subst, TyVar)
- cloneTyVarBndrs :: Subst -> [TyVar] -> UniqSupply -> (Subst, [TyVar])
- substVarBndr :: HasDebugCallStack => Subst -> TyCoVar -> (Subst, TyCoVar)
- substVarBndrs :: HasDebugCallStack => Subst -> [TyCoVar] -> (Subst, [TyCoVar])
- substTyVarBndr :: HasDebugCallStack => Subst -> TyVar -> (Subst, TyVar)
- substTyVarBndrs :: HasDebugCallStack => Subst -> [TyVar] -> (Subst, [TyVar])
- substCoVarBndr :: HasDebugCallStack => Subst -> CoVar -> (Subst, CoVar)
- substDCoVarSet :: Subst -> DCoVarSet -> DCoVarSet
- substTyVar :: Subst -> TyVar -> Type
- substTyVars :: Subst -> [TyVar] -> [Type]
- substTyVarToTyVar :: HasDebugCallStack => Subst -> TyVar -> TyVar
- substTyCoVars :: Subst -> [TyCoVar] -> [Type]
- substTyCoBndr :: Subst -> PiTyBinder -> (Subst, PiTyBinder)
- substForAllCoBndr :: Subst -> TyCoVar -> KindCoercion -> (Subst, TyCoVar, Coercion)
- substVarBndrUsing :: (Subst -> Type -> Type) -> Subst -> TyCoVar -> (Subst, TyCoVar)
- substForAllCoBndrUsing :: SwapFlag -> (Coercion -> Coercion) -> Subst -> TyCoVar -> KindCoercion -> (Subst, TyCoVar, KindCoercion)
- checkValidSubst :: HasDebugCallStack => Subst -> [Type] -> [Coercion] -> a -> a
- isValidTCvSubst :: Subst -> Bool

# Substitutions

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.

Constructors

Subst InScopeSet IdSubstEnv TvSubstEnv CvSubstEnv |

#### 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 `Type`s for `TyVar`s and `Kind`s for `KindVar`s

type CvSubstEnv = CoVarEnv Coercion Source #

A substitution of `Coercion`s for `CoVar`s

type IdSubstEnv = IdEnv CoreExpr Source #

A substitution of `Expr`s for non-coercion `Id`s

emptyIdSubstEnv :: IdSubstEnv Source #

emptyTvSubstEnv :: TvSubstEnv Source #

emptyCvSubstEnv :: CvSubstEnv Source #

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.

emptySubst :: Subst Source #

mkEmptySubst :: InScopeSet -> Subst Source #

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)

isEmptySubst :: Subst -> Bool Source #

mkTCvSubst :: InScopeSet -> TvSubstEnv -> CvSubstEnv -> Subst Source #

mkTvSubst :: InScopeSet -> TvSubstEnv -> Subst Source #

Make a TCvSubst with specified tyvar subst and empty covar subst

mkCvSubst :: InScopeSet -> CvSubstEnv -> Subst Source #

Make a TCvSubst with specified covar subst and empty tyvar subst

mkIdSubst :: InScopeSet -> IdSubstEnv -> Subst Source #

getTvSubstEnv :: Subst -> TvSubstEnv Source #

getIdSubstEnv :: Subst -> IdSubstEnv Source #

getCvSubstEnv :: Subst -> CvSubstEnv Source #

getSubstInScope :: Subst -> InScopeSet Source #

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

setInScope :: Subst -> InScopeSet -> Subst Source #

getSubstRangeTyCoFVs :: Subst -> VarSet Source #

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

isInScope :: Var -> Subst -> Bool Source #

elemSubst :: Var -> Subst -> Bool Source #

notElemSubst :: Var -> Subst -> Bool Source #

zapSubst :: Subst -> Subst Source #

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

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

Add the `Var` to the in-scope set

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

Add the `Var`s to the in-scope set: see also `extendInScope`

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

Add the `Var`s to the in-scope set: see also `extendInScope`

extendTCvSubst :: Subst -> TyCoVar -> Type -> Subst Source #

extendTCvSubstWithClone :: Subst -> TyCoVar -> TyCoVar -> Subst Source #

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

extendCvSubstWithClone :: Subst -> CoVar -> CoVar -> Subst Source #

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.

extendTvSubstWithClone :: Subst -> TyVar -> TyVar -> Subst Source #

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

Adds multiple `TyVar` substitutions to the `Subst`: see also `extendTvSubst`

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

extendTCvSubstList :: Subst -> [Var] -> [Type] -> Subst Source #

unionSubst :: Subst -> Subst -> Subst Source #

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

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

zipCoEnv :: HasDebugCallStack => [CoVar] -> [Coercion] -> CvSubstEnv Source #

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!

zipCvSubst :: HasDebugCallStack => [CoVar] -> [Coercion] -> Subst Source #

Generates the in-scope set for the `Subst` from the types in the incoming environment. No TyVars, please!

zipTCvSubst :: HasDebugCallStack => [TyCoVar] -> [Type] -> Subst Source #

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`

substTyWithCoVars :: [CoVar] -> [Coercion] -> Type -> Type Source #

Substitute covars within a type

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

Type substitution, see `zipTvSubst`

substTysWithCoVars :: HasDebugCallStack => [CoVar] -> [Coercion] -> [Type] -> [Type] Source #

Type substitution, see `zipTvSubst`

substCoWith :: HasDebugCallStack => [TyVar] -> [Type] -> Coercion -> Coercion Source #

Coercion substitution, see `zipTvSubst`

substTy :: HasDebugCallStack => Subst -> Type -> Type Source #

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

substTyAddInScope :: HasDebugCallStack => 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].

substScaledTy :: HasDebugCallStack => Subst -> Scaled Type -> Scaled Type Source #

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.

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

Substitute within several `Type`s 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.

substScaledTysUnchecked :: Subst -> [Scaled Type] -> [Scaled Type] Source #

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.

substScaledTyUnchecked :: HasDebugCallStack => Subst -> Scaled Type -> Scaled Type Source #

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.

substTyWithInScope :: HasDebugCallStack => InScopeSet -> [TyVar] -> [Type] -> Type -> Type Source #

Substitute tyvars within a type using a known `InScopeSet`. Pre-condition: the `in_scope` set should satisfy Note [The substitution invariant]; specifically it should include the free vars of `tys`, and of `ty` minus the domain of the subst.

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

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

substScaledTys :: HasDebugCallStack => Subst -> [Scaled Type] -> [Scaled Type] Source #

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

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

lookupTyVar :: Subst -> TyVar -> Maybe Type Source #

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

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

substCos :: HasDebugCallStack => Subst -> [Coercion] -> [Coercion] Source #

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

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

substCoVars :: Subst -> [CoVar] -> [Coercion] Source #

lookupCoVar :: Subst -> Var -> Maybe Coercion Source #

cloneTyVarBndr :: Subst -> TyVar -> Unique -> (Subst, TyVar) Source #

cloneTyVarBndrs :: Subst -> [TyVar] -> UniqSupply -> (Subst, [TyVar]) Source #

substVarBndr :: HasDebugCallStack => Subst -> TyCoVar -> (Subst, TyCoVar) Source #

substVarBndrs :: HasDebugCallStack => Subst -> [TyCoVar] -> (Subst, [TyCoVar]) Source #

substTyVarBndr :: HasDebugCallStack => Subst -> TyVar -> (Subst, TyVar) Source #

substTyVarBndrs :: HasDebugCallStack => Subst -> [TyVar] -> (Subst, [TyVar]) Source #

substCoVarBndr :: HasDebugCallStack => Subst -> CoVar -> (Subst, CoVar) Source #

substDCoVarSet :: Subst -> DCoVarSet -> DCoVarSet Source #

Perform a substitution within a `DVarSet` of free variables, returning the shallow free coercion variables.

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

substTyVars :: Subst -> [TyVar] -> [Type] Source #

substTyVarToTyVar :: HasDebugCallStack => Subst -> TyVar -> TyVar Source #

substTyCoVars :: Subst -> [TyCoVar] -> [Type] Source #

substTyCoBndr :: Subst -> PiTyBinder -> (Subst, PiTyBinder) Source #

substForAllCoBndr :: Subst -> TyCoVar -> KindCoercion -> (Subst, TyCoVar, Coercion) Source #

substVarBndrUsing :: (Subst -> Type -> Type) -> Subst -> TyCoVar -> (Subst, TyCoVar) Source #

substForAllCoBndrUsing :: SwapFlag -> (Coercion -> Coercion) -> Subst -> TyCoVar -> KindCoercion -> (Subst, TyCoVar, KindCoercion) Source #

checkValidSubst :: HasDebugCallStack => Subst -> [Type] -> [Coercion] -> a -> a Source #

This checks if the substitution satisfies the invariant from Note [The substitution invariant].

isValidTCvSubst :: Subst -> Bool Source #

When calling `substTy` it should be the case that the in-scope set in the substitution is a superset of the free vars of the range of the substitution. See also Note [The substitution invariant]. TODO: take into account ids and rename as isValidSubst