    {-
    (c) The University of Glasgow 2006
    (c) The GRASP/AQUA Project, Glasgow University, 1992-1998

    \section{@Vars@: Variables}
    -}

    {-# LANGUAGE MultiWayIf, PatternSynonyms #-}
    {-# OPTIONS_GHC -Wno-incomplete-record-updates #-}
    {-# LANGUAGE DeriveFunctor #-}

    -- |
    -- #name_types#
    -- GHC uses several kinds of name internally:
    --
    -- * 'GHC.Types.Name.Occurrence.OccName': see "GHC.Types.Name.Occurrence#name_types"
    --
    -- * 'GHC.Types.Name.Reader.RdrName': see "GHC.Types.Name.Reader#name_types"
    --
    -- * 'GHC.Types.Name.Name': see "GHC.Types.Name#name_types"
    --
    -- * 'GHC.Types.Id.Id': see "GHC.Types.Id#name_types"
    --
    -- * 'GHC.Types.Var.Var' is a synonym for the 'GHC.Types.Id.Id' type but it may additionally
    --   potentially contain type variables, which have a 'GHC.Core.TyCo.Rep.Kind'
    --   rather than a 'GHC.Core.TyCo.Rep.Type' and only contain some extra
    --   details during typechecking.
    --
    --   These 'Var' names may either be global or local, see "GHC.Types.Var#globalvslocal"
    --
    -- #globalvslocal#
    -- Global 'Id's and 'Var's are those that are imported or correspond
    --    to a data constructor, primitive operation, or record selectors.
    -- Local 'Id's and 'Var's are those bound within an expression
    --    (e.g. by a lambda) or at the top level of the module being compiled.

    module GHC.Types.Var (
            -- * The main data type and synonyms
            Var, CoVar, Id, NcId, DictId, DFunId, EvVar, EqVar, EvId, IpId, JoinId,
            TyVar, TcTyVar, TypeVar, KindVar, TKVar, TyCoVar,

            -- * In and Out variants
            InVar,  InCoVar,  InId,  InTyVar,  InTyCoVar,
            OutVar, OutCoVar, OutId, OutTyVar, OutTyCoVar,

            -- ** Taking 'Var's apart
            varName, varUnique, varType,
            varMultMaybe, idMult,

            -- ** Modifying 'Var's
            setVarName, setVarUnique, setVarType,
            updateVarType, updateVarTypeM,

            -- ** Constructing, taking apart, modifying 'Id's
            mkGlobalVar, mkLocalVar, mkExportedLocalVar, mkCoVar,
            idInfo, idDetails,
            lazySetIdInfo, setIdDetails, globaliseId,
            setIdExported, setIdNotExported, setIdMult,
            updateIdTypeButNotMult,
            updateIdTypeAndMult, updateIdTypeAndMultM,

            -- ** Predicates
            isId, isTyVar, isTcTyVar,
            isLocalVar, isLocalId, isLocalId_maybe, isCoVar, isNonCoVarId, isTyCoVar,
            isGlobalId, isExportedId,
            mustHaveLocalBinding,

            -- * ForAllTyFlags
            ForAllTyFlag(Invisible,Required,Specified,Inferred),
            Specificity(..),
            isVisibleForAllTyFlag, isInvisibleForAllTyFlag, isInferredForAllTyFlag,
            isSpecifiedForAllTyFlag,
            coreTyLamForAllTyFlag,

            -- * FunTyFlag
            FunTyFlag(..), isVisibleFunArg, isInvisibleFunArg, isFUNArg,
            mkFunTyFlag, visArg, invisArg,
            visArgTypeLike, visArgConstraintLike,
            invisArgTypeLike, invisArgConstraintLike,
            funTyFlagArgTypeOrConstraint, funTyFlagResultTypeOrConstraint,
            TypeOrConstraint(..),  -- Re-export this: it's an argument of FunTyFlag

            -- * PiTyBinder
            PiTyBinder(..), PiTyVarBinder,
            isInvisiblePiTyBinder, isInvisibleAnonPiTyBinder,
            isVisiblePiTyBinder,
            isTyBinder, isNamedPiTyBinder, isAnonPiTyBinder,
            namedPiTyBinder_maybe, anonPiTyBinderType_maybe, piTyBinderType,

            -- * TyVar's
            VarBndr(..), ForAllTyBinder, TyVarBinder,
            InvisTyBinder, InvisTVBinder, ReqTyBinder, ReqTVBinder,
            binderVar, binderVars, binderFlag, binderFlags, binderType,
            mkForAllTyBinder, mkForAllTyBinders,
            mkTyVarBinder, mkTyVarBinders,
            isVisibleForAllTyBinder, isInvisibleForAllTyBinder, isTyVarBinder,
            tyVarSpecToBinder, tyVarSpecToBinders, tyVarReqToBinder, tyVarReqToBinders,
            mapVarBndr, mapVarBndrs,

            -- ** ExportFlag
            ExportFlag(..),

            -- ** Constructing TyVar's
            mkTyVar, mkTcTyVar,

            -- ** Taking 'TyVar's apart
            tyVarName, tyVarKind, tcTyVarDetails, setTcTyVarDetails,

            -- ** Modifying 'TyVar's
            setTyVarName, setTyVarUnique, setTyVarKind, updateTyVarKind,
            updateTyVarKindM,

            nonDetCmpVar
            ) where

    import GHC.Prelude

    import {-# SOURCE #-}   GHC.Core.TyCo.Rep( Type, Kind, Mult, Scaled, scaledThing )
    import {-# SOURCE #-}   GHC.Core.TyCo.Ppr( pprKind )
    import {-# SOURCE #-}   GHC.Tc.Utils.TcType( TcTyVarDetails, pprTcTyVarDetails, vanillaSkolemTvUnk )
    import {-# SOURCE #-}   GHC.Types.Id.Info( IdDetails, IdInfo, coVarDetails, isCoVarDetails,
                                               vanillaIdInfo, pprIdDetails )
    import {-# SOURCE #-}   GHC.Builtin.Types ( manyDataConTy )
    import GHC.Types.Name hiding (varName)
    import GHC.Types.Unique ( Uniquable, Unique, getKey, getUnique
                            , nonDetCmpUnique )
    import GHC.Types.Basic( TypeOrConstraint(..) )
    import GHC.Utils.Misc
    import GHC.Utils.Binary
    import GHC.Utils.Outputable
    import GHC.Utils.Panic

    import GHC.Hs.Specificity ()
    import Language.Haskell.Syntax.Specificity
    import Control.DeepSeq

    import Data.Data

    {-
    ************************************************************************
    *                                                                      *
                         Synonyms
    *                                                                      *
    ************************************************************************
    -- These synonyms are here and not in Id because otherwise we need a very
    -- large number of SOURCE imports of "GHC.Types.Id" :-(
    -}

    -- | Identifier
    type Id    = Var       -- A term-level identifier
                           --  predicate: isId

    -- | Coercion Variable
    type CoVar = Id        -- See Note [Evidence: EvIds and CoVars]
                           --   predicate: isCoVar

    -- |
    type NcId  = Id        -- A term-level (value) variable that is
                           -- /not/ an (unlifted) coercion
                           --    predicate: isNonCoVarId

    -- | Type or kind Variable
    type TyVar   = Var     -- Type *or* kind variable (historical)

    -- | Type or Kind Variable
    type TKVar   = Var     -- Type *or* kind variable (historical)

    -- | Type variable that might be a metavariable
    type TcTyVar = Var

    -- | Type Variable
    type TypeVar = Var     -- Definitely a type variable

    -- | Kind Variable
    type KindVar = Var     -- Definitely a kind variable
                           -- See Note [Kind and type variables]

    -- See Note [Evidence: EvIds and CoVars]
    -- | Evidence Identifier
    type EvId   = Id        -- Term-level evidence: DictId, IpId, or EqVar

    -- | Evidence Variable
    type EvVar  = EvId      -- ...historical name for EvId

    -- | Dictionary Function Identifier
    type DFunId = Id        -- A dictionary function

    -- | Dictionary Identifier
    type DictId = EvId      -- A dictionary variable

    -- | Implicit parameter Identifier
    type IpId   = EvId      -- A term-level implicit parameter

    -- | Equality Variable
    type EqVar  = EvId      -- Boxed equality evidence
    type JoinId = Id        -- A join variable

    -- | Type or Coercion Variable
    type TyCoVar = Id       -- Type, *or* coercion variable
                            --   predicate: isTyCoVar

    {- Many passes apply a substitution, and it's very handy to have type
       synonyms to remind us whether or not the substitution has been applied -}

    type InVar      = Var
    type InTyVar    = TyVar
    type InCoVar    = CoVar
    type InTyCoVar  = TyCoVar
    type InId       = Id
    type OutVar     = Var
    type OutTyVar   = TyVar
    type OutCoVar   = CoVar
    type OutTyCoVar = TyCoVar
    type OutId      = Id

    {- Note [Evidence: EvIds and CoVars]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    * An EvId (evidence Id) is a term-level evidence variable
      (dictionary, implicit parameter, or equality). Could be boxed or unboxed.

    * DictId, IpId, and EqVar are synonyms when we know what kind of
      evidence we are talking about.  For example, an EqVar has type (t1 ~ t2).

    * A CoVar is always an un-lifted coercion, of type (t1 ~# t2) or (t1 ~R# t2)

    Note [Kind and type variables]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Before kind polymorphism, TyVar were used to mean type variables. Now
    they are used to mean kind *or* type variables. KindVar is used when we
    know for sure that it is a kind variable. In future, we might want to
    go over the whole compiler code to use:
       - TKVar   to mean kind or type variables
       - TypeVar to mean         type variables only
       - KindVar to mean kind         variables

    ************************************************************************
    *                                                                      *
    \subsection{The main data type declarations}
    *                                                                      *
    ************************************************************************

    Every @Var@ has a @Unique@, to uniquify it and for fast comparison, a
    @Type@, and an @IdInfo@ (non-essential info about it, e.g.,
    strictness).  The essential info about different kinds of @Vars@ is
    in its @VarDetails@.
    -}

    -- | Variable
    --
    -- Essentially a typed 'Name', that may also contain some additional information
    -- about the 'Var' and its use sites.
    data Var
      = TyVar {  -- Type and kind variables
                 -- see Note [Kind and type variables]
            Id -> Name
    varName    :: !Name,
            Id -> Unique
    realUnique :: {-# UNPACK #-} !Unique,
                                         -- ^ Key for fast comparison
                                         -- Identical to the Unique in the name,
                                         -- cached here for speed
            Id -> Mult
    varType    :: Kind           -- ^ The type or kind of the 'Var' in question
     }

      | TcTyVar {                           -- Used only during type inference
                                            -- Used for kind variables during
                                            -- inference, as well
            varName        :: !Name,
            realUnique     :: {-# UNPACK #-} !Unique,
            varType        :: Kind,
            Id -> TcTyVarDetails
    tc_tv_details  :: TcTyVarDetails
      }

      | Id {
            varName    :: !Name,
            realUnique :: {-# UNPACK #-} !Unique,
            varType    :: Type,
            Id -> Mult
    varMult    :: Mult,             -- See Note [Multiplicity of let binders]
            Id -> IdScope
    idScope    :: IdScope,
            Id -> IdDetails
    id_details :: IdDetails,        -- Stable, doesn't change
            Id -> IdInfo
    id_info    :: IdInfo }          -- Unstable, updated by simplifier

    -- | Identifier Scope
    data IdScope    -- See Note [GlobalId/LocalId]
      = GlobalId
      | LocalId ExportFlag

    data ExportFlag   -- See Note [ExportFlag on binders]
      = NotExported   -- ^ Not exported: may be discarded as dead code.
      | Exported      -- ^ Exported: kept alive

    {- Note [ExportFlag on binders]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    An ExportFlag of "Exported" on a top-level binder says "keep this
    binding alive; do not drop it as dead code".  This transitively
    keeps alive all the other top-level bindings that this binding refers
    to.  This property is persisted all the way down the pipeline, so that
    the binding will be compiled all the way to object code, and its
    symbols will appear in the linker symbol table.

    However, note that this use of "exported" is quite different to the
    export list on a Haskell module.  Setting the ExportFlag on an Id does
    /not/ mean that if you import the module (in Haskell source code) you
    will see this Id.  Of course, things that appear in the export list
    of the source Haskell module do indeed have their ExportFlag set.
    But many other things, such as dictionary functions, are kept alive
    by having their ExportFlag set, even though they are not exported
    in the source-code sense.

    We should probably use a different term for ExportFlag, like
    KeepAlive.

    Note [GlobalId/LocalId]
    ~~~~~~~~~~~~~~~~~~~~~~~
    A GlobalId is
      * always a constant (top-level)
      * imported, or data constructor, or primop, or record selector
      * has a Unique that is globally unique across the whole
        GHC invocation (a single invocation may compile multiple modules)
      * never treated as a candidate by the free-variable finder;
            it's a constant!

    A LocalId is
      * bound within an expression (lambda, case, local let(rec))
      * or defined at top level in the module being compiled
      * always treated as a candidate by the free-variable finder

    In the output of CoreTidy, top level Ids are all GlobalIds, which are then
    serialised into interface files. Do note however that CorePrep may introduce new
    LocalIds for local floats (even at the top level). These will be visible in STG
    and end up in generated code.

    Note [Multiplicity of let binders]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    In Core, let-binders' multiplicity is always completely determined by syntax:
    a recursive let will always have multiplicity Many (it's a prerequisite for
    being recursive), and non-recursive let doesn't have a conventional multiplicity,
    instead they act, for the purpose of multiplicity, as an alias for their
    right-hand side.

    Therefore, the `varMult` field of identifier is only used by binders in lambda
    and case expressions. In a let expression the `varMult` field holds an
    arbitrary value which will (and must!) be ignored.
    -}

    instance Outputable Var where
      ppr :: Id -> SDoc
    ppr Id
    var = SDoc -> (PprStyle -> SDoc) -> SDoc
    forall doc. IsOutput doc => doc -> (PprStyle -> SDoc) -> doc
    docWithStyle SDoc
    ppr_code PprStyle -> SDoc
    ppr_normal
        where
          -- don't display debug info with Code style (#25255)
          ppr_code :: SDoc
    ppr_code = Name -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr (Id -> Name
    varName Id
    var)
          ppr_normal :: PprStyle -> SDoc
    ppr_normal PprStyle
    sty = (SDocContext -> Bool) -> (Bool -> SDoc) -> SDoc
    forall a. (SDocContext -> a) -> (a -> SDoc) -> SDoc
    sdocOption SDocContext -> Bool
    sdocSuppressVarKinds ((Bool -> SDoc) -> SDoc) -> (Bool -> SDoc) -> SDoc
    forall a b. (a -> b) -> a -> b
    $ \Bool
    supp_var_kinds ->
                (Bool -> SDoc) -> SDoc
    forall doc. IsOutput doc => (Bool -> doc) -> doc
    getPprDebug ((Bool -> SDoc) -> SDoc) -> (Bool -> SDoc) -> SDoc
    forall a b. (a -> b) -> a -> b
    $ \Bool
    debug ->
                let
                  ppr_var :: SDoc
    ppr_var = case Id
    var of
                      (TyVar {})
                         | Bool
    debug
                         -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc
    brackets (String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "tv")

                      (TcTyVar {tc_tv_details :: Id -> TcTyVarDetails
    tc_tv_details = TcTyVarDetails
    d})
                         | PprStyle -> Bool
    dumpStyle PprStyle
    sty Bool -> Bool -> Bool
    || Bool
    debug
                         -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc
    brackets (TcTyVarDetails -> SDoc
    pprTcTyVarDetails TcTyVarDetails
    d)

                      (Id { idScope :: Id -> IdScope
    idScope = IdScope
    s, id_details :: Id -> IdDetails
    id_details = IdDetails
    d })
                         | Bool
    debug
                         -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc
    brackets (IdScope -> SDoc
    ppr_id_scope IdScope
    s SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <> IdDetails -> SDoc
    pprIdDetails IdDetails
    d)

                      Id
    _  -> SDoc
    forall doc. IsOutput doc => doc
    empty
                in if
                   |  Bool
    debug Bool -> Bool -> Bool
    && (Bool -> Bool
    not Bool
    supp_var_kinds)
                     -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc
    parens (Name -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr (Id -> Name
    varName Id
    var) SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> Maybe Mult -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr (Id -> Maybe Mult
    varMultMaybe Id
    var)
                                                  SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> SDoc
    ppr_var SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+>
                              SDoc
    dcolon SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> Mult -> SDoc
    pprKind (Id -> Mult
    tyVarKind Id
    var))
                   |  Bool
    otherwise
                     -> Name -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr (Id -> Name
    varName Id
    var) SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <> SDoc
    ppr_var

    ppr_id_scope :: IdScope -> SDoc
    ppr_id_scope :: IdScope -> SDoc
    ppr_id_scope IdScope
    GlobalId              = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "gid"
    ppr_id_scope (LocalId ExportFlag
    Exported)    = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "lidx"
    ppr_id_scope (LocalId ExportFlag
    NotExported) = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "lid"

    instance NamedThing Var where
      getName :: Id -> Name
    getName = Id -> Name
    varName

    instance Uniquable Var where
      getUnique :: Id -> Unique
    getUnique = Id -> Unique
    varUnique

    instance Eq Var where
        Id
    a == :: Id -> Id -> Bool
    == Id
    b = Id -> Unique
    realUnique Id
    a Unique -> Unique -> Bool
    forall a. Eq a => a -> a -> Bool
    == Id -> Unique
    realUnique Id
    b

    instance Ord Var where
        Id
    a <= :: Id -> Id -> Bool
    <= Id
    b = Unique -> Word64
    getKey (Id -> Unique
    realUnique Id
    a) Word64 -> Word64 -> Bool
    forall a. Ord a => a -> a -> Bool
    <= Unique -> Word64
    getKey (Id -> Unique
    realUnique Id
    b)
        Id
    a < :: Id -> Id -> Bool
    <  Id
    b = Unique -> Word64
    getKey (Id -> Unique
    realUnique Id
    a) Word64 -> Word64 -> Bool
    forall a. Ord a => a -> a -> Bool
    <  Unique -> Word64
    getKey (Id -> Unique
    realUnique Id
    b)
        Id
    a >= :: Id -> Id -> Bool
    >= Id
    b = Unique -> Word64
    getKey (Id -> Unique
    realUnique Id
    a) Word64 -> Word64 -> Bool
    forall a. Ord a => a -> a -> Bool
    >= Unique -> Word64
    getKey (Id -> Unique
    realUnique Id
    b)
        Id
    a > :: Id -> Id -> Bool
    >  Id
    b = Unique -> Word64
    getKey (Id -> Unique
    realUnique Id
    a) Word64 -> Word64 -> Bool
    forall a. Ord a => a -> a -> Bool
    >  Unique -> Word64
    getKey (Id -> Unique
    realUnique Id
    b)
        Id
    a compare :: Id -> Id -> Ordering
    `compare` Id
    b = Id
    a Id -> Id -> Ordering
    `nonDetCmpVar` Id
    b

    -- | Compare Vars by their Uniques.
    -- This is what Ord Var does, provided here to make it explicit at the
    -- call-site that it can introduce non-determinism.
    -- See Note [Unique Determinism]
    nonDetCmpVar :: Var -> Var -> Ordering
    nonDetCmpVar :: Id -> Id -> Ordering
    nonDetCmpVar Id
    a Id
    b = Id -> Unique
    varUnique Id
    a Unique -> Unique -> Ordering
    `nonDetCmpUnique` Id -> Unique
    varUnique Id
    b

    instance Data Var where
      -- don't traverse?
      toConstr :: Id -> Constr
    toConstr Id
    _   = String -> Constr
    abstractConstr String
    "Var"
      gunfold :: forall (c :: * -> *).
    (forall b r. Data b => c (b -> r) -> c r)
    -> (forall r. r -> c r) -> Constr -> c Id
    gunfold forall b r. Data b => c (b -> r) -> c r
    _ forall r. r -> c r
    _  = String -> Constr -> c Id
    forall a. HasCallStack => String -> a
    error String
    "gunfold"
      dataTypeOf :: Id -> DataType
    dataTypeOf Id
    _ = String -> DataType
    mkNoRepType String
    "Var"

    instance HasOccName Var where
      occName :: Id -> OccName
    occName = Name -> OccName
    nameOccName (Name -> OccName) -> (Id -> Name) -> Id -> OccName
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Id -> Name
    varName

    varUnique :: Var -> Unique
    varUnique :: Id -> Unique
    varUnique Id
    var = Id -> Unique
    realUnique Id
    var

    varMultMaybe :: Id -> Maybe Mult
    varMultMaybe :: Id -> Maybe Mult
    varMultMaybe (Id { varMult :: Id -> Mult
    varMult = Mult
    mult }) = Mult -> Maybe Mult
    forall a. a -> Maybe a
    Just Mult
    mult
    varMultMaybe Id
    _ = Maybe Mult
    forall a. Maybe a
    Nothing

    idMult :: HasDebugCallStack => Id -> Mult
    idMult :: HasDebugCallStack => Id -> Mult
    idMult (Id { varMult :: Id -> Mult
    varMult = Mult
    mult }) = Mult
    mult
    idMult Id
    non_id                  = String -> SDoc -> Mult
    forall a. HasCallStack => String -> SDoc -> a
    pprPanic String
    "idMult" (Id -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Id
    non_id)

    setVarUnique :: Var -> Unique -> Var
    setVarUnique :: Id -> Unique -> Id
    setVarUnique Id
    var Unique
    uniq
      = Id
    var { realUnique = uniq,
              varName = setNameUnique (varName var) uniq }

    setVarName :: Var -> Name -> Var
    setVarName :: Id -> Name -> Id
    setVarName Id
    var Name
    new_name
      = Id
    var { realUnique = getUnique new_name,
              varName = new_name }

    setVarType :: Var -> Type -> Var
    setVarType :: Id -> Mult -> Id
    setVarType Id
    id Mult
    ty = Id
    id { varType = ty }

    -- | Update a 'Var's type. Does not update the /multiplicity/
    -- stored in an 'Id', if any. Because of the possibility for
    -- abuse, ASSERTs that there is no multiplicity to update.
    updateVarType :: (Type -> Type) -> Var -> Var
    updateVarType :: (Mult -> Mult) -> Id -> Id
    updateVarType Mult -> Mult
    upd Id
    var
      = case Id
    var of
          Id { id_details :: Id -> IdDetails
    id_details = IdDetails
    details } -> Bool -> Id -> Id
    forall a. HasCallStack => Bool -> a -> a
    assert (IdDetails -> Bool
    isCoVarDetails IdDetails
    details) (Id -> Id) -> Id -> Id
    forall a b. (a -> b) -> a -> b
    $
                                         Id
    result
          Id
    _ -> Id
    result
      where
        result :: Id
    result = Id
    var { varType = upd (varType var) }

    -- | Update a 'Var's type monadically. Does not update the /multiplicity/
    -- stored in an 'Id', if any. Because of the possibility for
    -- abuse, ASSERTs that there is no multiplicity to update.
    updateVarTypeM :: Monad m => (Type -> m Type) -> Var -> m Var
    updateVarTypeM :: forall (m :: * -> *). Monad m => (Mult -> m Mult) -> Id -> m Id
    updateVarTypeM Mult -> m Mult
    upd Id
    var
      = case Id
    var of
          Id { id_details :: Id -> IdDetails
    id_details = IdDetails
    details } -> Bool -> m Id -> m Id
    forall a. HasCallStack => Bool -> a -> a
    assert (IdDetails -> Bool
    isCoVarDetails IdDetails
    details) (m Id -> m Id) -> m Id -> m Id
    forall a b. (a -> b) -> a -> b
    $
                                         m Id
    result
          Id
    _ -> m Id
    result
      where
        result :: m Id
    result = do { ty' <- Mult -> m Mult
    upd (Id -> Mult
    varType Id
    var)
                    ; return (var { varType = ty' }) }

    {- *********************************************************************
    *                                                                      *
    *                   FunTyFlag
    *                                                                      *
    ********************************************************************* -}

    -- | 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
    data FunTyFlag
      = FTF_T_T           -- (->)  Type -> Type
      | FTF_T_C           -- (-=>) Type -> Constraint
      | FTF_C_T           -- (=>)  Constraint -> Type
      | FTF_C_C           -- (==>) Constraint -> Constraint
      deriving (FunTyFlag -> FunTyFlag -> Bool
    (FunTyFlag -> FunTyFlag -> Bool)
    -> (FunTyFlag -> FunTyFlag -> Bool) -> Eq FunTyFlag
    forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
    $c== :: FunTyFlag -> FunTyFlag -> Bool
    == :: FunTyFlag -> FunTyFlag -> Bool
    $c/= :: FunTyFlag -> FunTyFlag -> Bool
    /= :: FunTyFlag -> FunTyFlag -> Bool
    Eq, Eq FunTyFlag
    Eq FunTyFlag =>
    (FunTyFlag -> FunTyFlag -> Ordering)
    -> (FunTyFlag -> FunTyFlag -> Bool)
    -> (FunTyFlag -> FunTyFlag -> Bool)
    -> (FunTyFlag -> FunTyFlag -> Bool)
    -> (FunTyFlag -> FunTyFlag -> Bool)
    -> (FunTyFlag -> FunTyFlag -> FunTyFlag)
    -> (FunTyFlag -> FunTyFlag -> FunTyFlag)
    -> Ord FunTyFlag
    FunTyFlag -> FunTyFlag -> Bool
    FunTyFlag -> FunTyFlag -> Ordering
    FunTyFlag -> FunTyFlag -> FunTyFlag
    forall a.
    Eq a =>
    (a -> a -> Ordering)
    -> (a -> a -> Bool)
    -> (a -> a -> Bool)
    -> (a -> a -> Bool)
    -> (a -> a -> Bool)
    -> (a -> a -> a)
    -> (a -> a -> a)
    -> Ord a
    $ccompare :: FunTyFlag -> FunTyFlag -> Ordering
    compare :: FunTyFlag -> FunTyFlag -> Ordering
    $c< :: FunTyFlag -> FunTyFlag -> Bool
    < :: FunTyFlag -> FunTyFlag -> Bool
    $c<= :: FunTyFlag -> FunTyFlag -> Bool
    <= :: FunTyFlag -> FunTyFlag -> Bool
    $c> :: FunTyFlag -> FunTyFlag -> Bool
    > :: FunTyFlag -> FunTyFlag -> Bool
    $c>= :: FunTyFlag -> FunTyFlag -> Bool
    >= :: FunTyFlag -> FunTyFlag -> Bool
    $cmax :: FunTyFlag -> FunTyFlag -> FunTyFlag
    max :: FunTyFlag -> FunTyFlag -> FunTyFlag
    $cmin :: FunTyFlag -> FunTyFlag -> FunTyFlag
    min :: FunTyFlag -> FunTyFlag -> FunTyFlag
    Ord, Typeable FunTyFlag
    Typeable FunTyFlag =>
    (forall (c :: * -> *).
     (forall d b. Data d => c (d -> b) -> d -> c b)
     -> (forall g. g -> c g) -> FunTyFlag -> c FunTyFlag)
    -> (forall (c :: * -> *).
        (forall b r. Data b => c (b -> r) -> c r)
        -> (forall r. r -> c r) -> Constr -> c FunTyFlag)
    -> (FunTyFlag -> Constr)
    -> (FunTyFlag -> DataType)
    -> (forall (t :: * -> *) (c :: * -> *).
        Typeable t =>
        (forall d. Data d => c (t d)) -> Maybe (c FunTyFlag))
    -> (forall (t :: * -> * -> *) (c :: * -> *).
        Typeable t =>
        (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c FunTyFlag))
    -> ((forall b. Data b => b -> b) -> FunTyFlag -> FunTyFlag)
    -> (forall r r'.
        (r -> r' -> r)
        -> r -> (forall d. Data d => d -> r') -> FunTyFlag -> r)
    -> (forall r r'.
        (r' -> r -> r)
        -> r -> (forall d. Data d => d -> r') -> FunTyFlag -> r)
    -> (forall u. (forall d. Data d => d -> u) -> FunTyFlag -> [u])
    -> (forall u.
        Int -> (forall d. Data d => d -> u) -> FunTyFlag -> u)
    -> (forall (m :: * -> *).
        Monad m =>
        (forall d. Data d => d -> m d) -> FunTyFlag -> m FunTyFlag)
    -> (forall (m :: * -> *).
        MonadPlus m =>
        (forall d. Data d => d -> m d) -> FunTyFlag -> m FunTyFlag)
    -> (forall (m :: * -> *).
        MonadPlus m =>
        (forall d. Data d => d -> m d) -> FunTyFlag -> m FunTyFlag)
    -> Data FunTyFlag
    FunTyFlag -> Constr
    FunTyFlag -> DataType
    (forall b. Data b => b -> b) -> FunTyFlag -> FunTyFlag
    forall a.
    Typeable a =>
    (forall (c :: * -> *).
     (forall d b. Data d => c (d -> b) -> d -> c b)
     -> (forall g. g -> c g) -> a -> c a)
    -> (forall (c :: * -> *).
        (forall b r. Data b => c (b -> r) -> c r)
        -> (forall r. r -> c r) -> Constr -> c a)
    -> (a -> Constr)
    -> (a -> DataType)
    -> (forall (t :: * -> *) (c :: * -> *).
        Typeable t =>
        (forall d. Data d => c (t d)) -> Maybe (c a))
    -> (forall (t :: * -> * -> *) (c :: * -> *).
        Typeable t =>
        (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c a))
    -> ((forall b. Data b => b -> b) -> a -> a)
    -> (forall r r'.
        (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> a -> r)
    -> (forall r r'.
        (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> a -> r)
    -> (forall u. (forall d. Data d => d -> u) -> a -> [u])
    -> (forall u. Int -> (forall d. Data d => d -> u) -> a -> u)
    -> (forall (m :: * -> *).
        Monad m =>
        (forall d. Data d => d -> m d) -> a -> m a)
    -> (forall (m :: * -> *).
        MonadPlus m =>
        (forall d. Data d => d -> m d) -> a -> m a)
    -> (forall (m :: * -> *).
        MonadPlus m =>
        (forall d. Data d => d -> m d) -> a -> m a)
    -> Data a
    forall u. Int -> (forall d. Data d => d -> u) -> FunTyFlag -> u
    forall u. (forall d. Data d => d -> u) -> FunTyFlag -> [u]
    forall r r'.
    (r -> r' -> r)
    -> r -> (forall d. Data d => d -> r') -> FunTyFlag -> r
    forall r r'.
    (r' -> r -> r)
    -> r -> (forall d. Data d => d -> r') -> FunTyFlag -> r
    forall (m :: * -> *).
    Monad m =>
    (forall d. Data d => d -> m d) -> FunTyFlag -> m FunTyFlag
    forall (m :: * -> *).
    MonadPlus m =>
    (forall d. Data d => d -> m d) -> FunTyFlag -> m FunTyFlag
    forall (c :: * -> *).
    (forall b r. Data b => c (b -> r) -> c r)
    -> (forall r. r -> c r) -> Constr -> c FunTyFlag
    forall (c :: * -> *).
    (forall d b. Data d => c (d -> b) -> d -> c b)
    -> (forall g. g -> c g) -> FunTyFlag -> c FunTyFlag
    forall (t :: * -> *) (c :: * -> *).
    Typeable t =>
    (forall d. Data d => c (t d)) -> Maybe (c FunTyFlag)
    forall (t :: * -> * -> *) (c :: * -> *).
    Typeable t =>
    (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c FunTyFlag)
    $cgfoldl :: forall (c :: * -> *).
    (forall d b. Data d => c (d -> b) -> d -> c b)
    -> (forall g. g -> c g) -> FunTyFlag -> c FunTyFlag
    gfoldl :: forall (c :: * -> *).
    (forall d b. Data d => c (d -> b) -> d -> c b)
    -> (forall g. g -> c g) -> FunTyFlag -> c FunTyFlag
    $cgunfold :: forall (c :: * -> *).
    (forall b r. Data b => c (b -> r) -> c r)
    -> (forall r. r -> c r) -> Constr -> c FunTyFlag
    gunfold :: forall (c :: * -> *).
    (forall b r. Data b => c (b -> r) -> c r)
    -> (forall r. r -> c r) -> Constr -> c FunTyFlag
    $ctoConstr :: FunTyFlag -> Constr
    toConstr :: FunTyFlag -> Constr
    $cdataTypeOf :: FunTyFlag -> DataType
    dataTypeOf :: FunTyFlag -> DataType
    $cdataCast1 :: forall (t :: * -> *) (c :: * -> *).
    Typeable t =>
    (forall d. Data d => c (t d)) -> Maybe (c FunTyFlag)
    dataCast1 :: forall (t :: * -> *) (c :: * -> *).
    Typeable t =>
    (forall d. Data d => c (t d)) -> Maybe (c FunTyFlag)
    $cdataCast2 :: forall (t :: * -> * -> *) (c :: * -> *).
    Typeable t =>
    (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c FunTyFlag)
    dataCast2 :: forall (t :: * -> * -> *) (c :: * -> *).
    Typeable t =>
    (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c FunTyFlag)
    $cgmapT :: (forall b. Data b => b -> b) -> FunTyFlag -> FunTyFlag
    gmapT :: (forall b. Data b => b -> b) -> FunTyFlag -> FunTyFlag
    $cgmapQl :: forall r r'.
    (r -> r' -> r)
    -> r -> (forall d. Data d => d -> r') -> FunTyFlag -> r
    gmapQl :: forall r r'.
    (r -> r' -> r)
    -> r -> (forall d. Data d => d -> r') -> FunTyFlag -> r
    $cgmapQr :: forall r r'.
    (r' -> r -> r)
    -> r -> (forall d. Data d => d -> r') -> FunTyFlag -> r
    gmapQr :: forall r r'.
    (r' -> r -> r)
    -> r -> (forall d. Data d => d -> r') -> FunTyFlag -> r
    $cgmapQ :: forall u. (forall d. Data d => d -> u) -> FunTyFlag -> [u]
    gmapQ :: forall u. (forall d. Data d => d -> u) -> FunTyFlag -> [u]
    $cgmapQi :: forall u. Int -> (forall d. Data d => d -> u) -> FunTyFlag -> u
    gmapQi :: forall u. Int -> (forall d. Data d => d -> u) -> FunTyFlag -> u
    $cgmapM :: forall (m :: * -> *).
    Monad m =>
    (forall d. Data d => d -> m d) -> FunTyFlag -> m FunTyFlag
    gmapM :: forall (m :: * -> *).
    Monad m =>
    (forall d. Data d => d -> m d) -> FunTyFlag -> m FunTyFlag
    $cgmapMp :: forall (m :: * -> *).
    MonadPlus m =>
    (forall d. Data d => d -> m d) -> FunTyFlag -> m FunTyFlag
    gmapMp :: forall (m :: * -> *).
    MonadPlus m =>
    (forall d. Data d => d -> m d) -> FunTyFlag -> m FunTyFlag
    $cgmapMo :: forall (m :: * -> *).
    MonadPlus m =>
    (forall d. Data d => d -> m d) -> FunTyFlag -> m FunTyFlag
    gmapMo :: forall (m :: * -> *).
    MonadPlus m =>
    (forall d. Data d => d -> m d) -> FunTyFlag -> m FunTyFlag
    Data)

    instance Outputable FunTyFlag where
      ppr :: FunTyFlag -> SDoc
    ppr FunTyFlag
    FTF_T_T  = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "[->]"
      ppr FunTyFlag
    FTF_T_C  = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "[-=>]"
      ppr FunTyFlag
    FTF_C_T  = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "[=>]"
      ppr FunTyFlag
    FTF_C_C  = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "[==>]"

    instance Binary FunTyFlag where
      put_ :: WriteBinHandle -> FunTyFlag -> IO ()
    put_ WriteBinHandle
    bh FunTyFlag
    FTF_T_T = WriteBinHandle -> Word8 -> IO ()
    putByte WriteBinHandle
    bh Word8
    0
      put_ WriteBinHandle
    bh FunTyFlag
    FTF_T_C = WriteBinHandle -> Word8 -> IO ()
    putByte WriteBinHandle
    bh Word8
    1
      put_ WriteBinHandle
    bh FunTyFlag
    FTF_C_T = WriteBinHandle -> Word8 -> IO ()
    putByte WriteBinHandle
    bh Word8
    2
      put_ WriteBinHandle
    bh FunTyFlag
    FTF_C_C = WriteBinHandle -> Word8 -> IO ()
    putByte WriteBinHandle
    bh Word8
    3

      get :: ReadBinHandle -> IO FunTyFlag
    get ReadBinHandle
    bh = do
        h <- ReadBinHandle -> IO Word8
    getByte ReadBinHandle
    bh
        case h of
          Word8
    0 -> FunTyFlag -> IO FunTyFlag
    forall a. a -> IO a
    forall (m :: * -> *) a. Monad m => a -> m a
    return FunTyFlag
    FTF_T_T
          Word8
    1 -> FunTyFlag -> IO FunTyFlag
    forall a. a -> IO a
    forall (m :: * -> *) a. Monad m => a -> m a
    return FunTyFlag
    FTF_T_C
          Word8
    2 -> FunTyFlag -> IO FunTyFlag
    forall a. a -> IO a
    forall (m :: * -> *) a. Monad m => a -> m a
    return FunTyFlag
    FTF_C_T
          Word8
    _ -> FunTyFlag -> IO FunTyFlag
    forall a. a -> IO a
    forall (m :: * -> *) a. Monad m => a -> m a
    return FunTyFlag
    FTF_C_C

    instance NFData FunTyFlag where
      rnf :: FunTyFlag -> ()
    rnf FunTyFlag
    FTF_T_T = ()
      rnf FunTyFlag
    FTF_T_C = ()
      rnf FunTyFlag
    FTF_C_T = ()
      rnf FunTyFlag
    FTF_C_C = ()

    mkFunTyFlag :: TypeOrConstraint -> TypeOrConstraint -> FunTyFlag
    mkFunTyFlag :: TypeOrConstraint -> TypeOrConstraint -> FunTyFlag
    mkFunTyFlag TypeOrConstraint
    TypeLike       TypeOrConstraint
    torc = TypeOrConstraint -> FunTyFlag
    visArg TypeOrConstraint
    torc
    mkFunTyFlag TypeOrConstraint
    ConstraintLike TypeOrConstraint
    torc = TypeOrConstraint -> FunTyFlag
    invisArg TypeOrConstraint
    torc

    visArg :: TypeOrConstraint -> FunTyFlag
    visArg :: TypeOrConstraint -> FunTyFlag
    visArg TypeOrConstraint
    TypeLike       = FunTyFlag
    FTF_T_T
    visArg TypeOrConstraint
    ConstraintLike = FunTyFlag
    FTF_T_C

    visArgTypeLike :: FunTyFlag
    visArgTypeLike :: FunTyFlag
    visArgTypeLike = FunTyFlag
    FTF_T_T

    visArgConstraintLike :: FunTyFlag
    visArgConstraintLike :: FunTyFlag
    visArgConstraintLike = FunTyFlag
    FTF_T_C

    invisArg :: TypeOrConstraint -> FunTyFlag
    invisArg :: TypeOrConstraint -> FunTyFlag
    invisArg TypeOrConstraint
    TypeLike       = FunTyFlag
    FTF_C_T
    invisArg TypeOrConstraint
    ConstraintLike = FunTyFlag
    FTF_C_C

    invisArgTypeLike :: FunTyFlag
    invisArgTypeLike :: FunTyFlag
    invisArgTypeLike = FunTyFlag
    FTF_C_T

    invisArgConstraintLike :: FunTyFlag
    invisArgConstraintLike :: FunTyFlag
    invisArgConstraintLike = FunTyFlag
    FTF_C_C

    isInvisibleFunArg :: FunTyFlag -> Bool
    isInvisibleFunArg :: FunTyFlag -> Bool
    isInvisibleFunArg FunTyFlag
    af = Bool -> Bool
    not (FunTyFlag -> Bool
    isVisibleFunArg FunTyFlag
    af)

    isVisibleFunArg :: FunTyFlag -> Bool
    isVisibleFunArg :: FunTyFlag -> Bool
    isVisibleFunArg FunTyFlag
    FTF_T_T = Bool
    True
    isVisibleFunArg FunTyFlag
    FTF_T_C = Bool
    True
    isVisibleFunArg FunTyFlag
    _       = Bool
    False

    isFUNArg :: FunTyFlag -> Bool
    -- This one, FUN, or (->), has an extra multiplicity argument
    isFUNArg :: FunTyFlag -> Bool
    isFUNArg FunTyFlag
    FTF_T_T = Bool
    True
    isFUNArg FunTyFlag
    _       = Bool
    False

    funTyFlagArgTypeOrConstraint :: FunTyFlag -> TypeOrConstraint
    -- Whether it /takes/ a type or a constraint
    funTyFlagArgTypeOrConstraint :: FunTyFlag -> TypeOrConstraint
    funTyFlagArgTypeOrConstraint FunTyFlag
    FTF_T_T = TypeOrConstraint
    TypeLike
    funTyFlagArgTypeOrConstraint FunTyFlag
    FTF_T_C = TypeOrConstraint
    TypeLike
    funTyFlagArgTypeOrConstraint FunTyFlag
    _       = TypeOrConstraint
    ConstraintLike

    funTyFlagResultTypeOrConstraint :: FunTyFlag -> TypeOrConstraint
    -- Whether it /returns/ a type or a constraint
    funTyFlagResultTypeOrConstraint :: FunTyFlag -> TypeOrConstraint
    funTyFlagResultTypeOrConstraint FunTyFlag
    FTF_T_T = TypeOrConstraint
    TypeLike
    funTyFlagResultTypeOrConstraint FunTyFlag
    FTF_C_T = TypeOrConstraint
    TypeLike
    funTyFlagResultTypeOrConstraint FunTyFlag
    _       = TypeOrConstraint
    ConstraintLike

    {- Note [FunTyFlag]
    ~~~~~~~~~~~~~~~~~~~~~
    FunTyFlag is used principally in the FunTy constructor of Type.
      FunTy FTF_T_T t1 t2   means   t1 -> t2
      FunTy FTF_C_T t1 t2   means   t1 => t2
      FunTy FTF_T_C t1 t2   means   t1 -=> t2
      FunTy FTF_C_C t1 t2   means   t1 ==> t2

    However, the FunTyFlag in a FunTy is just redundant, cached
    information.  In (FunTy { ft_af = af, ft_arg = t1, ft_res = t2 })
      ---------------------------------------------
      (isPredTy t1)   (isPredTy ty)     FunTyFlag
      ---------------------------------------------
         False           False         FTF_T_T
         False           True          FTF_T_C
         True            False         FTF_C_T
         True            True          FTF_C_C
    where isPredTy is defined in GHC.Core.Predicate, and sees if t1's
    kind is Constraint.  See GHC.Core.Type.chooseFunTyFlag, and
    GHC.Core.Predicate Note [Types for coercions, predicates, and evidence]

    The term (Lam b e) doesn't carry an FunTyFlag; instead it uses
    mkFunctionType when we want to get its types; see mkLamType.  This is
    just an engineering choice; we could cache here too if we wanted.

    Why bother with all this? After all, we are in Core, where (=>) and
    (->) behave the same.  We maintain this distinction throughout Core so
    that we can cheaply and conveniently determine
    * How to print a type
    * How to split up a type: tcSplitSigmaTy
    * How to specialise it (over type classes; GHC.Core.Opt.Specialise)

    For the specialisation point, consider
    (\ (d :: Ord a). blah).  We want to give it type
               (Ord a => blah_ty)
    with a fat arrow; that is, using mkInvisFunTy, not mkVisFunTy.
    Why?  Because the /specialiser/ treats dictionary arguments specially.
    Suppose we do w/w on 'foo', thus (#11272, #6056)
       foo :: Ord a => Int -> blah
       foo a d x = case x of I# x' -> $wfoo @a d x'

       $wfoo :: Ord a => Int# -> blah

    Now, at a call we see (foo @Int dOrdInt).  The specialiser will
    specialise this to $sfoo, where
       $sfoo :: Int -> blah
       $sfoo x = case x of I# x' -> $wfoo @Int dOrdInt x'

    Now we /must/ also specialise $wfoo!  But it wasn't user-written,
    and has a type built with mkLamTypes.

    Conclusion: the easiest thing is to make mkLamType build
                (c => ty)
    when the argument is a predicate type.  See GHC.Core.TyCo.Rep
    Note [Types for coercions, predicates, and evidence]
    -}

    {- *********************************************************************
    *                                                                      *
    *                   VarBndr, ForAllTyBinder
    *                                                                      *
    ********************************************************************* -}

    {- Note [The VarBndr type and its uses]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    VarBndr is polymorphic in both var and visibility fields.
    Currently there are nine different uses of 'VarBndr':

    * Var.ForAllTyBinder = VarBndr TyCoVar ForAllTyFlag
      Binder of a forall-type; see ForAllTy in GHC.Core.TyCo.Rep

    * Var.TyVarBinder = VarBndr TyVar ForAllTyFlag
      Subset of ForAllTyBinder when we are sure the binder is a TyVar

    * Var.InvisTVBinder = VarBndr TyVar Specificity
      Specialised form of TyVarBinder, when ForAllTyFlag = Invisible s
      See GHC.Core.Type.splitForAllInvisTVBinders

    * Var.ReqTVBinder = VarBndr TyVar ()
      Specialised form of TyVarBinder, when ForAllTyFlag = Required
      See GHC.Core.Type.splitForAllReqTVBinders
      This one is barely used

    * TyCon.TyConBinder = VarBndr TyVar TyConBndrVis
      Binders of a TyCon; see TyCon in GHC.Core.TyCon

    * IfaceType.IfaceForAllBndr     = VarBndr IfaceBndr ForAllTyFlag
    * IfaceType.IfaceForAllSpecBndr = VarBndr IfaceBndr Specificity
    * IfaceType.IfaceTyConBinder    = VarBndr IfaceBndr TyConBndrVis
    -}

    data VarBndr var argf = Bndr var argf
      -- See Note [The VarBndr type and its uses]
      deriving( Typeable (VarBndr var argf)
    Typeable (VarBndr var argf) =>
    (forall (c :: * -> *).
     (forall d b. Data d => c (d -> b) -> d -> c b)
     -> (forall g. g -> c g)
     -> VarBndr var argf
     -> c (VarBndr var argf))
    -> (forall (c :: * -> *).
        (forall b r. Data b => c (b -> r) -> c r)
        -> (forall r. r -> c r) -> Constr -> c (VarBndr var argf))
    -> (VarBndr var argf -> Constr)
    -> (VarBndr var argf -> DataType)
    -> (forall (t :: * -> *) (c :: * -> *).
        Typeable t =>
        (forall d. Data d => c (t d)) -> Maybe (c (VarBndr var argf)))
    -> (forall (t :: * -> * -> *) (c :: * -> *).
        Typeable t =>
        (forall d e. (Data d, Data e) => c (t d e))
        -> Maybe (c (VarBndr var argf)))
    -> ((forall b. Data b => b -> b)
        -> VarBndr var argf -> VarBndr var argf)
    -> (forall r r'.
        (r -> r' -> r)
        -> r -> (forall d. Data d => d -> r') -> VarBndr var argf -> r)
    -> (forall r r'.
        (r' -> r -> r)
        -> r -> (forall d. Data d => d -> r') -> VarBndr var argf -> r)
    -> (forall u.
        (forall d. Data d => d -> u) -> VarBndr var argf -> [u])
    -> (forall u.
        Int -> (forall d. Data d => d -> u) -> VarBndr var argf -> u)
    -> (forall (m :: * -> *).
        Monad m =>
        (forall d. Data d => d -> m d)
        -> VarBndr var argf -> m (VarBndr var argf))
    -> (forall (m :: * -> *).
        MonadPlus m =>
        (forall d. Data d => d -> m d)
        -> VarBndr var argf -> m (VarBndr var argf))
    -> (forall (m :: * -> *).
        MonadPlus m =>
        (forall d. Data d => d -> m d)
        -> VarBndr var argf -> m (VarBndr var argf))
    -> Data (VarBndr var argf)
    VarBndr var argf -> Constr
    VarBndr var argf -> DataType
    (forall b. Data b => b -> b)
    -> VarBndr var argf -> VarBndr var argf
    forall a.
    Typeable a =>
    (forall (c :: * -> *).
     (forall d b. Data d => c (d -> b) -> d -> c b)
     -> (forall g. g -> c g) -> a -> c a)
    -> (forall (c :: * -> *).
        (forall b r. Data b => c (b -> r) -> c r)
        -> (forall r. r -> c r) -> Constr -> c a)
    -> (a -> Constr)
    -> (a -> DataType)
    -> (forall (t :: * -> *) (c :: * -> *).
        Typeable t =>
        (forall d. Data d => c (t d)) -> Maybe (c a))
    -> (forall (t :: * -> * -> *) (c :: * -> *).
        Typeable t =>
        (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c a))
    -> ((forall b. Data b => b -> b) -> a -> a)
    -> (forall r r'.
        (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> a -> r)
    -> (forall r r'.
        (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> a -> r)
    -> (forall u. (forall d. Data d => d -> u) -> a -> [u])
    -> (forall u. Int -> (forall d. Data d => d -> u) -> a -> u)
    -> (forall (m :: * -> *).
        Monad m =>
        (forall d. Data d => d -> m d) -> a -> m a)
    -> (forall (m :: * -> *).
        MonadPlus m =>
        (forall d. Data d => d -> m d) -> a -> m a)
    -> (forall (m :: * -> *).
        MonadPlus m =>
        (forall d. Data d => d -> m d) -> a -> m a)
    -> Data a
    forall u.
    Int -> (forall d. Data d => d -> u) -> VarBndr var argf -> u
    forall u. (forall d. Data d => d -> u) -> VarBndr var argf -> [u]
    forall var argf.
    (Data var, Data argf) =>
    Typeable (VarBndr var argf)
    forall var argf.
    (Data var, Data argf) =>
    VarBndr var argf -> Constr
    forall var argf.
    (Data var, Data argf) =>
    VarBndr var argf -> DataType
    forall var argf.
    (Data var, Data argf) =>
    (forall b. Data b => b -> b)
    -> VarBndr var argf -> VarBndr var argf
    forall var argf u.
    (Data var, Data argf) =>
    Int -> (forall d. Data d => d -> u) -> VarBndr var argf -> u
    forall var argf u.
    (Data var, Data argf) =>
    (forall d. Data d => d -> u) -> VarBndr var argf -> [u]
    forall var argf r r'.
    (Data var, Data argf) =>
    (r -> r' -> r)
    -> r -> (forall d. Data d => d -> r') -> VarBndr var argf -> r
    forall var argf r r'.
    (Data var, Data argf) =>
    (r' -> r -> r)
    -> r -> (forall d. Data d => d -> r') -> VarBndr var argf -> r
    forall var argf (m :: * -> *).
    (Data var, Data argf, Monad m) =>
    (forall d. Data d => d -> m d)
    -> VarBndr var argf -> m (VarBndr var argf)
    forall var argf (m :: * -> *).
    (Data var, Data argf, MonadPlus m) =>
    (forall d. Data d => d -> m d)
    -> VarBndr var argf -> m (VarBndr var argf)
    forall var argf (c :: * -> *).
    (Data var, Data argf) =>
    (forall b r. Data b => c (b -> r) -> c r)
    -> (forall r. r -> c r) -> Constr -> c (VarBndr var argf)
    forall var argf (c :: * -> *).
    (Data var, Data argf) =>
    (forall d b. Data d => c (d -> b) -> d -> c b)
    -> (forall g. g -> c g) -> VarBndr var argf -> c (VarBndr var argf)
    forall var argf (t :: * -> *) (c :: * -> *).
    (Data var, Data argf, Typeable t) =>
    (forall d. Data d => c (t d)) -> Maybe (c (VarBndr var argf))
    forall var argf (t :: * -> * -> *) (c :: * -> *).
    (Data var, Data argf, Typeable t) =>
    (forall d e. (Data d, Data e) => c (t d e))
    -> Maybe (c (VarBndr var argf))
    forall r r'.
    (r -> r' -> r)
    -> r -> (forall d. Data d => d -> r') -> VarBndr var argf -> r
    forall r r'.
    (r' -> r -> r)
    -> r -> (forall d. Data d => d -> r') -> VarBndr var argf -> r
    forall (m :: * -> *).
    Monad m =>
    (forall d. Data d => d -> m d)
    -> VarBndr var argf -> m (VarBndr var argf)
    forall (m :: * -> *).
    MonadPlus m =>
    (forall d. Data d => d -> m d)
    -> VarBndr var argf -> m (VarBndr var argf)
    forall (c :: * -> *).
    (forall b r. Data b => c (b -> r) -> c r)
    -> (forall r. r -> c r) -> Constr -> c (VarBndr var argf)
    forall (c :: * -> *).
    (forall d b. Data d => c (d -> b) -> d -> c b)
    -> (forall g. g -> c g) -> VarBndr var argf -> c (VarBndr var argf)
    forall (t :: * -> *) (c :: * -> *).
    Typeable t =>
    (forall d. Data d => c (t d)) -> Maybe (c (VarBndr var argf))
    forall (t :: * -> * -> *) (c :: * -> *).
    Typeable t =>
    (forall d e. (Data d, Data e) => c (t d e))
    -> Maybe (c (VarBndr var argf))
    $cgfoldl :: forall var argf (c :: * -> *).
    (Data var, Data argf) =>
    (forall d b. Data d => c (d -> b) -> d -> c b)
    -> (forall g. g -> c g) -> VarBndr var argf -> c (VarBndr var argf)
    gfoldl :: forall (c :: * -> *).
    (forall d b. Data d => c (d -> b) -> d -> c b)
    -> (forall g. g -> c g) -> VarBndr var argf -> c (VarBndr var argf)
    $cgunfold :: forall var argf (c :: * -> *).
    (Data var, Data argf) =>
    (forall b r. Data b => c (b -> r) -> c r)
    -> (forall r. r -> c r) -> Constr -> c (VarBndr var argf)
    gunfold :: forall (c :: * -> *).
    (forall b r. Data b => c (b -> r) -> c r)
    -> (forall r. r -> c r) -> Constr -> c (VarBndr var argf)
    $ctoConstr :: forall var argf.
    (Data var, Data argf) =>
    VarBndr var argf -> Constr
    toConstr :: VarBndr var argf -> Constr
    $cdataTypeOf :: forall var argf.
    (Data var, Data argf) =>
    VarBndr var argf -> DataType
    dataTypeOf :: VarBndr var argf -> DataType
    $cdataCast1 :: forall var argf (t :: * -> *) (c :: * -> *).
    (Data var, Data argf, Typeable t) =>
    (forall d. Data d => c (t d)) -> Maybe (c (VarBndr var argf))
    dataCast1 :: forall (t :: * -> *) (c :: * -> *).
    Typeable t =>
    (forall d. Data d => c (t d)) -> Maybe (c (VarBndr var argf))
    $cdataCast2 :: forall var argf (t :: * -> * -> *) (c :: * -> *).
    (Data var, Data argf, Typeable t) =>
    (forall d e. (Data d, Data e) => c (t d e))
    -> Maybe (c (VarBndr var argf))
    dataCast2 :: forall (t :: * -> * -> *) (c :: * -> *).
    Typeable t =>
    (forall d e. (Data d, Data e) => c (t d e))
    -> Maybe (c (VarBndr var argf))
    $cgmapT :: forall var argf.
    (Data var, Data argf) =>
    (forall b. Data b => b -> b)
    -> VarBndr var argf -> VarBndr var argf
    gmapT :: (forall b. Data b => b -> b)
    -> VarBndr var argf -> VarBndr var argf
    $cgmapQl :: forall var argf r r'.
    (Data var, Data argf) =>
    (r -> r' -> r)
    -> r -> (forall d. Data d => d -> r') -> VarBndr var argf -> r
    gmapQl :: forall r r'.
    (r -> r' -> r)
    -> r -> (forall d. Data d => d -> r') -> VarBndr var argf -> r
    $cgmapQr :: forall var argf r r'.
    (Data var, Data argf) =>
    (r' -> r -> r)
    -> r -> (forall d. Data d => d -> r') -> VarBndr var argf -> r
    gmapQr :: forall r r'.
    (r' -> r -> r)
    -> r -> (forall d. Data d => d -> r') -> VarBndr var argf -> r
    $cgmapQ :: forall var argf u.
    (Data var, Data argf) =>
    (forall d. Data d => d -> u) -> VarBndr var argf -> [u]
    gmapQ :: forall u. (forall d. Data d => d -> u) -> VarBndr var argf -> [u]
    $cgmapQi :: forall var argf u.
    (Data var, Data argf) =>
    Int -> (forall d. Data d => d -> u) -> VarBndr var argf -> u
    gmapQi :: forall u.
    Int -> (forall d. Data d => d -> u) -> VarBndr var argf -> u
    $cgmapM :: forall var argf (m :: * -> *).
    (Data var, Data argf, Monad m) =>
    (forall d. Data d => d -> m d)
    -> VarBndr var argf -> m (VarBndr var argf)
    gmapM :: forall (m :: * -> *).
    Monad m =>
    (forall d. Data d => d -> m d)
    -> VarBndr var argf -> m (VarBndr var argf)
    $cgmapMp :: forall var argf (m :: * -> *).
    (Data var, Data argf, MonadPlus m) =>
    (forall d. Data d => d -> m d)
    -> VarBndr var argf -> m (VarBndr var argf)
    gmapMp :: forall (m :: * -> *).
    MonadPlus m =>
    (forall d. Data d => d -> m d)
    -> VarBndr var argf -> m (VarBndr var argf)
    $cgmapMo :: forall var argf (m :: * -> *).
    (Data var, Data argf, MonadPlus m) =>
    (forall d. Data d => d -> m d)
    -> VarBndr var argf -> m (VarBndr var argf)
    gmapMo :: forall (m :: * -> *).
    MonadPlus m =>
    (forall d. Data d => d -> m d)
    -> VarBndr var argf -> m (VarBndr var argf)
    Data, VarBndr var argf -> VarBndr var argf -> Bool
    (VarBndr var argf -> VarBndr var argf -> Bool)
    -> (VarBndr var argf -> VarBndr var argf -> Bool)
    -> Eq (VarBndr var argf)
    forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
    forall var argf.
    (Eq var, Eq argf) =>
    VarBndr var argf -> VarBndr var argf -> Bool
    $c== :: forall var argf.
    (Eq var, Eq argf) =>
    VarBndr var argf -> VarBndr var argf -> Bool
    == :: VarBndr var argf -> VarBndr var argf -> Bool
    $c/= :: forall var argf.
    (Eq var, Eq argf) =>
    VarBndr var argf -> VarBndr var argf -> Bool
    /= :: VarBndr var argf -> VarBndr var argf -> Bool
    Eq, Eq (VarBndr var argf)
    Eq (VarBndr var argf) =>
    (VarBndr var argf -> VarBndr var argf -> Ordering)
    -> (VarBndr var argf -> VarBndr var argf -> Bool)
    -> (VarBndr var argf -> VarBndr var argf -> Bool)
    -> (VarBndr var argf -> VarBndr var argf -> Bool)
    -> (VarBndr var argf -> VarBndr var argf -> Bool)
    -> (VarBndr var argf -> VarBndr var argf -> VarBndr var argf)
    -> (VarBndr var argf -> VarBndr var argf -> VarBndr var argf)
    -> Ord (VarBndr var argf)
    VarBndr var argf -> VarBndr var argf -> Bool
    VarBndr var argf -> VarBndr var argf -> Ordering
    VarBndr var argf -> VarBndr var argf -> VarBndr var argf
    forall a.
    Eq a =>
    (a -> a -> Ordering)
    -> (a -> a -> Bool)
    -> (a -> a -> Bool)
    -> (a -> a -> Bool)
    -> (a -> a -> Bool)
    -> (a -> a -> a)
    -> (a -> a -> a)
    -> Ord a
    forall var argf. (Ord var, Ord argf) => Eq (VarBndr var argf)
    forall var argf.
    (Ord var, Ord argf) =>
    VarBndr var argf -> VarBndr var argf -> Bool
    forall var argf.
    (Ord var, Ord argf) =>
    VarBndr var argf -> VarBndr var argf -> Ordering
    forall var argf.
    (Ord var, Ord argf) =>
    VarBndr var argf -> VarBndr var argf -> VarBndr var argf
    $ccompare :: forall var argf.
    (Ord var, Ord argf) =>
    VarBndr var argf -> VarBndr var argf -> Ordering
    compare :: VarBndr var argf -> VarBndr var argf -> Ordering
    $c< :: forall var argf.
    (Ord var, Ord argf) =>
    VarBndr var argf -> VarBndr var argf -> Bool
    < :: VarBndr var argf -> VarBndr var argf -> Bool
    $c<= :: forall var argf.
    (Ord var, Ord argf) =>
    VarBndr var argf -> VarBndr var argf -> Bool
    <= :: VarBndr var argf -> VarBndr var argf -> Bool
    $c> :: forall var argf.
    (Ord var, Ord argf) =>
    VarBndr var argf -> VarBndr var argf -> Bool
    > :: VarBndr var argf -> VarBndr var argf -> Bool
    $c>= :: forall var argf.
    (Ord var, Ord argf) =>
    VarBndr var argf -> VarBndr var argf -> Bool
    >= :: VarBndr var argf -> VarBndr var argf -> Bool
    $cmax :: forall var argf.
    (Ord var, Ord argf) =>
    VarBndr var argf -> VarBndr var argf -> VarBndr var argf
    max :: VarBndr var argf -> VarBndr var argf -> VarBndr var argf
    $cmin :: forall var argf.
    (Ord var, Ord argf) =>
    VarBndr var argf -> VarBndr var argf -> VarBndr var argf
    min :: VarBndr var argf -> VarBndr var argf -> VarBndr var argf
    Ord)

    -- | 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
    -- See Note [VarBndrs, ForAllTyBinders, TyConBinders, and visibility]
    --
    -- A 'TyVarBinder' is a binder with only TyVar
    type ForAllTyBinder = VarBndr TyCoVar ForAllTyFlag
    type InvisTyBinder  = VarBndr TyCoVar Specificity
    type ReqTyBinder    = VarBndr TyCoVar ()

    type TyVarBinder    = VarBndr TyVar   ForAllTyFlag
    type InvisTVBinder  = VarBndr TyVar   Specificity
    type ReqTVBinder    = VarBndr TyVar   ()

    tyVarSpecToBinders :: [VarBndr a Specificity] -> [VarBndr a ForAllTyFlag]
    tyVarSpecToBinders :: forall a. [VarBndr a Specificity] -> [VarBndr a ForAllTyFlag]
    tyVarSpecToBinders = (VarBndr a Specificity -> VarBndr a ForAllTyFlag)
    -> [VarBndr a Specificity] -> [VarBndr a ForAllTyFlag]
    forall a b. (a -> b) -> [a] -> [b]
    map VarBndr a Specificity -> VarBndr a ForAllTyFlag
    forall a. VarBndr a Specificity -> VarBndr a ForAllTyFlag
    tyVarSpecToBinder

    tyVarSpecToBinder :: VarBndr a Specificity -> VarBndr a ForAllTyFlag
    tyVarSpecToBinder :: forall a. VarBndr a Specificity -> VarBndr a ForAllTyFlag
    tyVarSpecToBinder (Bndr a
    tv Specificity
    vis) = a -> ForAllTyFlag -> VarBndr a ForAllTyFlag
    forall var argf. var -> argf -> VarBndr var argf
    Bndr a
    tv (Specificity -> ForAllTyFlag
    Invisible Specificity
    vis)

    tyVarReqToBinders :: [VarBndr a ()] -> [VarBndr a ForAllTyFlag]
    tyVarReqToBinders :: forall a. [VarBndr a ()] -> [VarBndr a ForAllTyFlag]
    tyVarReqToBinders = (VarBndr a () -> VarBndr a ForAllTyFlag)
    -> [VarBndr a ()] -> [VarBndr a ForAllTyFlag]
    forall a b. (a -> b) -> [a] -> [b]
    map VarBndr a () -> VarBndr a ForAllTyFlag
    forall a. VarBndr a () -> VarBndr a ForAllTyFlag
    tyVarReqToBinder

    tyVarReqToBinder :: VarBndr a () -> VarBndr a ForAllTyFlag
    tyVarReqToBinder :: forall a. VarBndr a () -> VarBndr a ForAllTyFlag
    tyVarReqToBinder (Bndr a
    tv ()
    _) = a -> ForAllTyFlag -> VarBndr a ForAllTyFlag
    forall var argf. var -> argf -> VarBndr var argf
    Bndr a
    tv ForAllTyFlag
    Required

    isVisibleForAllTyBinder :: ForAllTyBinder -> Bool
    isVisibleForAllTyBinder :: ForAllTyBinder -> Bool
    isVisibleForAllTyBinder (Bndr Id
    _ ForAllTyFlag
    vis) = ForAllTyFlag -> Bool
    isVisibleForAllTyFlag ForAllTyFlag
    vis

    isInvisibleForAllTyBinder :: ForAllTyBinder -> Bool
    isInvisibleForAllTyBinder :: ForAllTyBinder -> Bool
    isInvisibleForAllTyBinder (Bndr Id
    _ ForAllTyFlag
    vis) = ForAllTyFlag -> Bool
    isInvisibleForAllTyFlag ForAllTyFlag
    vis

    binderVar :: VarBndr tv argf -> tv
    binderVar :: forall tv argf. VarBndr tv argf -> tv
    binderVar (Bndr tv
    v argf
    _) = tv
    v

    binderVars :: [VarBndr tv argf] -> [tv]
    binderVars :: forall tv argf. [VarBndr tv argf] -> [tv]
    binderVars [VarBndr tv argf]
    tvbs = (VarBndr tv argf -> tv) -> [VarBndr tv argf] -> [tv]
    forall a b. (a -> b) -> [a] -> [b]
    map VarBndr tv argf -> tv
    forall tv argf. VarBndr tv argf -> tv
    binderVar [VarBndr tv argf]
    tvbs

    binderFlag :: VarBndr tv argf -> argf
    binderFlag :: forall tv argf. VarBndr tv argf -> argf
    binderFlag (Bndr tv
    _ argf
    argf) = argf
    argf

    binderFlags :: [VarBndr tv argf] -> [argf]
    binderFlags :: forall tv argf. [VarBndr tv argf] -> [argf]
    binderFlags [VarBndr tv argf]
    tvbs = (VarBndr tv argf -> argf) -> [VarBndr tv argf] -> [argf]
    forall a b. (a -> b) -> [a] -> [b]
    map VarBndr tv argf -> argf
    forall tv argf. VarBndr tv argf -> argf
    binderFlag [VarBndr tv argf]
    tvbs

    binderType :: VarBndr TyCoVar argf -> Type
    binderType :: forall argf. VarBndr Id argf -> Mult
    binderType (Bndr Id
    tv argf
    _) = Id -> Mult
    varType Id
    tv

    isTyVarBinder :: VarBndr TyCoVar vis -> Bool
    isTyVarBinder :: forall vis. VarBndr Id vis -> Bool
    isTyVarBinder (Bndr Id
    tcv vis
    _) = Id -> Bool
    isTyVar Id
    tcv

    -- | Make a named binder
    mkForAllTyBinder :: vis -> TyCoVar -> VarBndr TyCoVar vis
    mkForAllTyBinder :: forall vis. vis -> Id -> VarBndr Id vis
    mkForAllTyBinder vis
    vis Id
    var = Id -> vis -> VarBndr Id vis
    forall var argf. var -> argf -> VarBndr var argf
    Bndr Id
    var vis
    vis

    -- | Make a named binder
    -- 'var' should be a type variable
    mkTyVarBinder :: vis -> TyVar -> VarBndr TyVar vis
    mkTyVarBinder :: forall vis. vis -> Id -> VarBndr Id vis
    mkTyVarBinder vis
    vis Id
    var
      = Bool -> VarBndr Id vis -> VarBndr Id vis
    forall a. HasCallStack => Bool -> a -> a
    assert (Id -> Bool
    isTyVar Id
    var) (VarBndr Id vis -> VarBndr Id vis)
    -> VarBndr Id vis -> VarBndr Id vis
    forall a b. (a -> b) -> a -> b
    $
        Id -> vis -> VarBndr Id vis
    forall var argf. var -> argf -> VarBndr var argf
    Bndr Id
    var vis
    vis

    -- | Make many named binders
    mkForAllTyBinders :: vis -> [TyCoVar] -> [VarBndr TyCoVar vis]
    mkForAllTyBinders :: forall vis. vis -> [Id] -> [VarBndr Id vis]
    mkForAllTyBinders vis
    vis = (Id -> VarBndr Id vis) -> [Id] -> [VarBndr Id vis]
    forall a b. (a -> b) -> [a] -> [b]
    map (vis -> Id -> VarBndr Id vis
    forall vis. vis -> Id -> VarBndr Id vis
    mkForAllTyBinder vis
    vis)

    -- | Make many named binders
    -- Input vars should be type variables
    mkTyVarBinders :: vis -> [TyVar] -> [VarBndr TyVar vis]
    mkTyVarBinders :: forall vis. vis -> [Id] -> [VarBndr Id vis]
    mkTyVarBinders vis
    vis = (Id -> VarBndr Id vis) -> [Id] -> [VarBndr Id vis]
    forall a b. (a -> b) -> [a] -> [b]
    map (vis -> Id -> VarBndr Id vis
    forall vis. vis -> Id -> VarBndr Id vis
    mkTyVarBinder vis
    vis)

    mapVarBndr :: (var -> var') -> (VarBndr var flag) -> (VarBndr var' flag)
    mapVarBndr :: forall var var' flag.
    (var -> var') -> VarBndr var flag -> VarBndr var' flag
    mapVarBndr var -> var'
    f (Bndr var
    v flag
    fl) = var' -> flag -> VarBndr var' flag
    forall var argf. var -> argf -> VarBndr var argf
    Bndr (var -> var'
    f var
    v) flag
    fl

    mapVarBndrs :: (var -> var') -> [VarBndr var flag] -> [VarBndr var' flag]
    mapVarBndrs :: forall var var' flag.
    (var -> var') -> [VarBndr var flag] -> [VarBndr var' flag]
    mapVarBndrs var -> var'
    f = (VarBndr var flag -> VarBndr var' flag)
    -> [VarBndr var flag] -> [VarBndr var' flag]
    forall a b. (a -> b) -> [a] -> [b]
    map ((var -> var') -> VarBndr var flag -> VarBndr var' flag
    forall var var' flag.
    (var -> var') -> VarBndr var flag -> VarBndr var' flag
    mapVarBndr var -> var'
    f)

    instance Outputable tv => Outputable (VarBndr tv ForAllTyFlag) where
      ppr :: VarBndr tv ForAllTyFlag -> SDoc
    ppr (Bndr tv
    v ForAllTyFlag
    Required)  = tv -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr tv
    v
      ppr (Bndr tv
    v ForAllTyFlag
    Specified) = Char -> SDoc
    forall doc. IsLine doc => Char -> doc
    char Char
    '@' SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <> tv -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr tv
    v
      ppr (Bndr tv
    v ForAllTyFlag
    Inferred)  = SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc
    braces (tv -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr tv
    v)

    instance Outputable tv => Outputable (VarBndr tv Specificity) where
      ppr :: VarBndr tv Specificity -> SDoc
    ppr = VarBndr tv ForAllTyFlag -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr (VarBndr tv ForAllTyFlag -> SDoc)
    -> (VarBndr tv Specificity -> VarBndr tv ForAllTyFlag)
    -> VarBndr tv Specificity
    -> SDoc
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . VarBndr tv Specificity -> VarBndr tv ForAllTyFlag
    forall a. VarBndr a Specificity -> VarBndr a ForAllTyFlag
    tyVarSpecToBinder

    instance (Binary tv, Binary vis) => Binary (VarBndr tv vis) where
      put_ :: WriteBinHandle -> VarBndr tv vis -> IO ()
    put_ WriteBinHandle
    bh (Bndr tv
    tv vis
    vis) = do { WriteBinHandle -> tv -> IO ()
    forall a. Binary a => WriteBinHandle -> a -> IO ()
    put_ WriteBinHandle
    bh tv
    tv; WriteBinHandle -> vis -> IO ()
    forall a. Binary a => WriteBinHandle -> a -> IO ()
    put_ WriteBinHandle
    bh vis
    vis }

      get :: ReadBinHandle -> IO (VarBndr tv vis)
    get ReadBinHandle
    bh = do { tv <- ReadBinHandle -> IO tv
    forall a. Binary a => ReadBinHandle -> IO a
    get ReadBinHandle
    bh; vis <- get bh; return (Bndr tv vis) }

    instance (NFData tv, NFData vis) => NFData (VarBndr tv vis) where
      rnf :: VarBndr tv vis -> ()
    rnf (Bndr tv
    tv vis
    vis) = tv -> ()
    forall a. NFData a => a -> ()
    rnf tv
    tv () -> () -> ()
    forall a b. a -> b -> b
    `seq` vis -> ()
    forall a. NFData a => a -> ()
    rnf vis
    vis

    instance NamedThing tv => NamedThing (VarBndr tv flag) where
      getName :: VarBndr tv flag -> Name
    getName (Bndr tv
    tv flag
    _) = tv -> Name
    forall a. NamedThing a => a -> Name
    getName tv
    tv

    {- **********************************************************************
    *                                                                       *
                      PiTyBinder
    *                                                                       *
    ********************************************************************** -}

    -- | 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]
    data PiTyBinder
      = Named ForAllTyBinder          -- A type-lambda binder, with a ForAllTyFlag
      | Anon (Scaled Type) FunTyFlag  -- A term-lambda binder. Type here can be CoercionTy.
                                      -- The arrow is described by the FunTyFlag
      deriving Typeable PiTyBinder
    Typeable PiTyBinder =>
    (forall (c :: * -> *).
     (forall d b. Data d => c (d -> b) -> d -> c b)
     -> (forall g. g -> c g) -> PiTyBinder -> c PiTyBinder)
    -> (forall (c :: * -> *).
        (forall b r. Data b => c (b -> r) -> c r)
        -> (forall r. r -> c r) -> Constr -> c PiTyBinder)
    -> (PiTyBinder -> Constr)
    -> (PiTyBinder -> DataType)
    -> (forall (t :: * -> *) (c :: * -> *).
        Typeable t =>
        (forall d. Data d => c (t d)) -> Maybe (c PiTyBinder))
    -> (forall (t :: * -> * -> *) (c :: * -> *).
        Typeable t =>
        (forall d e. (Data d, Data e) => c (t d e))
        -> Maybe (c PiTyBinder))
    -> ((forall b. Data b => b -> b) -> PiTyBinder -> PiTyBinder)
    -> (forall r r'.
        (r -> r' -> r)
        -> r -> (forall d. Data d => d -> r') -> PiTyBinder -> r)
    -> (forall r r'.
        (r' -> r -> r)
        -> r -> (forall d. Data d => d -> r') -> PiTyBinder -> r)
    -> (forall u. (forall d. Data d => d -> u) -> PiTyBinder -> [u])
    -> (forall u.
        Int -> (forall d. Data d => d -> u) -> PiTyBinder -> u)
    -> (forall (m :: * -> *).
        Monad m =>
        (forall d. Data d => d -> m d) -> PiTyBinder -> m PiTyBinder)
    -> (forall (m :: * -> *).
        MonadPlus m =>
        (forall d. Data d => d -> m d) -> PiTyBinder -> m PiTyBinder)
    -> (forall (m :: * -> *).
        MonadPlus m =>
        (forall d. Data d => d -> m d) -> PiTyBinder -> m PiTyBinder)
    -> Data PiTyBinder
    PiTyBinder -> Constr
    PiTyBinder -> DataType
    (forall b. Data b => b -> b) -> PiTyBinder -> PiTyBinder
    forall a.
    Typeable a =>
    (forall (c :: * -> *).
     (forall d b. Data d => c (d -> b) -> d -> c b)
     -> (forall g. g -> c g) -> a -> c a)
    -> (forall (c :: * -> *).
        (forall b r. Data b => c (b -> r) -> c r)
        -> (forall r. r -> c r) -> Constr -> c a)
    -> (a -> Constr)
    -> (a -> DataType)
    -> (forall (t :: * -> *) (c :: * -> *).
        Typeable t =>
        (forall d. Data d => c (t d)) -> Maybe (c a))
    -> (forall (t :: * -> * -> *) (c :: * -> *).
        Typeable t =>
        (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c a))
    -> ((forall b. Data b => b -> b) -> a -> a)
    -> (forall r r'.
        (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> a -> r)
    -> (forall r r'.
        (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> a -> r)
    -> (forall u. (forall d. Data d => d -> u) -> a -> [u])
    -> (forall u. Int -> (forall d. Data d => d -> u) -> a -> u)
    -> (forall (m :: * -> *).
        Monad m =>
        (forall d. Data d => d -> m d) -> a -> m a)
    -> (forall (m :: * -> *).
        MonadPlus m =>
        (forall d. Data d => d -> m d) -> a -> m a)
    -> (forall (m :: * -> *).
        MonadPlus m =>
        (forall d. Data d => d -> m d) -> a -> m a)
    -> Data a
    forall u. Int -> (forall d. Data d => d -> u) -> PiTyBinder -> u
    forall u. (forall d. Data d => d -> u) -> PiTyBinder -> [u]
    forall r r'.
    (r -> r' -> r)
    -> r -> (forall d. Data d => d -> r') -> PiTyBinder -> r
    forall r r'.
    (r' -> r -> r)
    -> r -> (forall d. Data d => d -> r') -> PiTyBinder -> r
    forall (m :: * -> *).
    Monad m =>
    (forall d. Data d => d -> m d) -> PiTyBinder -> m PiTyBinder
    forall (m :: * -> *).
    MonadPlus m =>
    (forall d. Data d => d -> m d) -> PiTyBinder -> m PiTyBinder
    forall (c :: * -> *).
    (forall b r. Data b => c (b -> r) -> c r)
    -> (forall r. r -> c r) -> Constr -> c PiTyBinder
    forall (c :: * -> *).
    (forall d b. Data d => c (d -> b) -> d -> c b)
    -> (forall g. g -> c g) -> PiTyBinder -> c PiTyBinder
    forall (t :: * -> *) (c :: * -> *).
    Typeable t =>
    (forall d. Data d => c (t d)) -> Maybe (c PiTyBinder)
    forall (t :: * -> * -> *) (c :: * -> *).
    Typeable t =>
    (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c PiTyBinder)
    $cgfoldl :: forall (c :: * -> *).
    (forall d b. Data d => c (d -> b) -> d -> c b)
    -> (forall g. g -> c g) -> PiTyBinder -> c PiTyBinder
    gfoldl :: forall (c :: * -> *).
    (forall d b. Data d => c (d -> b) -> d -> c b)
    -> (forall g. g -> c g) -> PiTyBinder -> c PiTyBinder
    $cgunfold :: forall (c :: * -> *).
    (forall b r. Data b => c (b -> r) -> c r)
    -> (forall r. r -> c r) -> Constr -> c PiTyBinder
    gunfold :: forall (c :: * -> *).
    (forall b r. Data b => c (b -> r) -> c r)
    -> (forall r. r -> c r) -> Constr -> c PiTyBinder
    $ctoConstr :: PiTyBinder -> Constr
    toConstr :: PiTyBinder -> Constr
    $cdataTypeOf :: PiTyBinder -> DataType
    dataTypeOf :: PiTyBinder -> DataType
    $cdataCast1 :: forall (t :: * -> *) (c :: * -> *).
    Typeable t =>
    (forall d. Data d => c (t d)) -> Maybe (c PiTyBinder)
    dataCast1 :: forall (t :: * -> *) (c :: * -> *).
    Typeable t =>
    (forall d. Data d => c (t d)) -> Maybe (c PiTyBinder)
    $cdataCast2 :: forall (t :: * -> * -> *) (c :: * -> *).
    Typeable t =>
    (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c PiTyBinder)
    dataCast2 :: forall (t :: * -> * -> *) (c :: * -> *).
    Typeable t =>
    (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c PiTyBinder)
    $cgmapT :: (forall b. Data b => b -> b) -> PiTyBinder -> PiTyBinder
    gmapT :: (forall b. Data b => b -> b) -> PiTyBinder -> PiTyBinder
    $cgmapQl :: forall r r'.
    (r -> r' -> r)
    -> r -> (forall d. Data d => d -> r') -> PiTyBinder -> r
    gmapQl :: forall r r'.
    (r -> r' -> r)
    -> r -> (forall d. Data d => d -> r') -> PiTyBinder -> r
    $cgmapQr :: forall r r'.
    (r' -> r -> r)
    -> r -> (forall d. Data d => d -> r') -> PiTyBinder -> r
    gmapQr :: forall r r'.
    (r' -> r -> r)
    -> r -> (forall d. Data d => d -> r') -> PiTyBinder -> r
    $cgmapQ :: forall u. (forall d. Data d => d -> u) -> PiTyBinder -> [u]
    gmapQ :: forall u. (forall d. Data d => d -> u) -> PiTyBinder -> [u]
    $cgmapQi :: forall u. Int -> (forall d. Data d => d -> u) -> PiTyBinder -> u
    gmapQi :: forall u. Int -> (forall d. Data d => d -> u) -> PiTyBinder -> u
    $cgmapM :: forall (m :: * -> *).
    Monad m =>
    (forall d. Data d => d -> m d) -> PiTyBinder -> m PiTyBinder
    gmapM :: forall (m :: * -> *).
    Monad m =>
    (forall d. Data d => d -> m d) -> PiTyBinder -> m PiTyBinder
    $cgmapMp :: forall (m :: * -> *).
    MonadPlus m =>
    (forall d. Data d => d -> m d) -> PiTyBinder -> m PiTyBinder
    gmapMp :: forall (m :: * -> *).
    MonadPlus m =>
    (forall d. Data d => d -> m d) -> PiTyBinder -> m PiTyBinder
    $cgmapMo :: forall (m :: * -> *).
    MonadPlus m =>
    (forall d. Data d => d -> m d) -> PiTyBinder -> m PiTyBinder
    gmapMo :: forall (m :: * -> *).
    MonadPlus m =>
    (forall d. Data d => d -> m d) -> PiTyBinder -> m PiTyBinder
    Data

    instance Outputable PiTyBinder where
      ppr :: PiTyBinder -> SDoc
    ppr (Anon Scaled Mult
    ty FunTyFlag
    af) = FunTyFlag -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr FunTyFlag
    af SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> Scaled Mult -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Scaled Mult
    ty
      ppr (Named (Bndr Id
    v ForAllTyFlag
    Required))  = Id -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Id
    v
      ppr (Named (Bndr Id
    v ForAllTyFlag
    Specified)) = Char -> SDoc
    forall doc. IsLine doc => Char -> doc
    char Char
    '@' SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <> Id -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Id
    v
      ppr (Named (Bndr Id
    v ForAllTyFlag
    Inferred))  = SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc
    braces (Id -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Id
    v)

    -- | 'PiTyVarBinder' is like 'PiTyBinder', but there can only be 'TyVar'
    -- in the 'Named' field.
    type PiTyVarBinder = PiTyBinder

    -- | Does this binder bind an invisible argument?
    isInvisiblePiTyBinder :: PiTyBinder -> Bool
    isInvisiblePiTyBinder :: PiTyBinder -> Bool
    isInvisiblePiTyBinder (Named (Bndr Id
    _ ForAllTyFlag
    vis)) = ForAllTyFlag -> Bool
    isInvisibleForAllTyFlag ForAllTyFlag
    vis
    isInvisiblePiTyBinder (Anon Scaled Mult
    _ FunTyFlag
    af)          = FunTyFlag -> Bool
    isInvisibleFunArg FunTyFlag
    af

    isInvisibleAnonPiTyBinder :: PiTyBinder -> Bool
    isInvisibleAnonPiTyBinder :: PiTyBinder -> Bool
    isInvisibleAnonPiTyBinder (Named {})  = Bool
    False
    isInvisibleAnonPiTyBinder (Anon Scaled Mult
    _ FunTyFlag
    af) = FunTyFlag -> Bool
    isInvisibleFunArg FunTyFlag
    af

    -- | Does this binder bind a visible argument?
    isVisiblePiTyBinder :: PiTyBinder -> Bool
    isVisiblePiTyBinder :: PiTyBinder -> Bool
    isVisiblePiTyBinder = Bool -> Bool
    not (Bool -> Bool) -> (PiTyBinder -> Bool) -> PiTyBinder -> Bool
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . PiTyBinder -> Bool
    isInvisiblePiTyBinder

    isNamedPiTyBinder :: PiTyBinder -> Bool
    isNamedPiTyBinder :: PiTyBinder -> Bool
    isNamedPiTyBinder (Named {}) = Bool
    True
    isNamedPiTyBinder (Anon {})  = Bool
    False

    namedPiTyBinder_maybe :: PiTyBinder -> Maybe TyCoVar
    namedPiTyBinder_maybe :: PiTyBinder -> Maybe Id
    namedPiTyBinder_maybe (Named ForAllTyBinder
    tv) = Id -> Maybe Id
    forall a. a -> Maybe a
    Just (Id -> Maybe Id) -> Id -> Maybe Id
    forall a b. (a -> b) -> a -> b
    $ ForAllTyBinder -> Id
    forall tv argf. VarBndr tv argf -> tv
    binderVar ForAllTyBinder
    tv
    namedPiTyBinder_maybe PiTyBinder
    _          = Maybe Id
    forall a. Maybe a
    Nothing

    -- | Does this binder bind a variable that is /not/ erased? Returns
    -- 'True' for anonymous binders.
    isAnonPiTyBinder :: PiTyBinder -> Bool
    isAnonPiTyBinder :: PiTyBinder -> Bool
    isAnonPiTyBinder (Named {}) = Bool
    False
    isAnonPiTyBinder (Anon {})  = Bool
    True

    -- | Extract a relevant type, if there is one.
    anonPiTyBinderType_maybe :: PiTyBinder -> Maybe Type
    anonPiTyBinderType_maybe :: PiTyBinder -> Maybe Mult
    anonPiTyBinderType_maybe (Named {})  = Maybe Mult
    forall a. Maybe a
    Nothing
    anonPiTyBinderType_maybe (Anon Scaled Mult
    ty FunTyFlag
    _) = Mult -> Maybe Mult
    forall a. a -> Maybe a
    Just (Scaled Mult -> Mult
    forall a. Scaled a -> a
    scaledThing Scaled Mult
    ty)

    -- | If its a named binder, is the binder a tyvar?
    -- Returns True for nondependent binder.
    -- This check that we're really returning a *Ty*Binder (as opposed to a
    -- coercion binder). That way, if/when we allow coercion quantification
    -- in more places, we'll know we missed updating some function.
    isTyBinder :: PiTyBinder -> Bool
    isTyBinder :: PiTyBinder -> Bool
    isTyBinder (Named ForAllTyBinder
    bnd) = ForAllTyBinder -> Bool
    forall vis. VarBndr Id vis -> Bool
    isTyVarBinder ForAllTyBinder
    bnd
    isTyBinder PiTyBinder
    _ = Bool
    True

    piTyBinderType :: PiTyBinder -> Type
    piTyBinderType :: PiTyBinder -> Mult
    piTyBinderType (Named (Bndr Id
    tv ForAllTyFlag
    _)) = Id -> Mult
    varType Id
    tv
    piTyBinderType (Anon Scaled Mult
    ty FunTyFlag
    _)         = Scaled Mult -> Mult
    forall a. Scaled a -> a
    scaledThing Scaled Mult
    ty

    {- Note [PiTyBinders]
    ~~~~~~~~~~~~~~~~~~~
    But a type like
       forall a. Maybe a -> forall b. (a,b) -> b

    can be decomposed to a telescope of type [PiTyBinder], using splitPiTys.
    That function splits off all leading foralls and arrows, giving
       ([Named a, Anon (Maybe a), Named b, Anon (a,b)], b)

    A PiTyBinder represents the type of binders -- that is, the type of an
    argument to a Pi-type. GHC Core currently supports two different
    Pi-types:

     * Anon ty1 fun_flag: a non-dependent function type,
       written with ->, e.g. ty1 -> ty2
       represented as FunTy ty1 ty2. These are
       lifted to Coercions with the corresponding FunCo.

     * Named (Var tv forall_flag)
        A dependent compile-time-only polytype,
       written with forall, e.g.  forall (a:*). ty
       represented as ForAllTy (Bndr a v) ty

    Both forms of Pi-types classify terms/types that take an argument. In other
    words, if `x` is either a function or a polytype, `x arg` makes sense
    (for an appropriate `arg`).

    Wrinkles

    * The Anon constructor of PiTyBinder contains a FunTyFlag.  Since
      the PiTyBinder really only describes the /argument/ it should perhaps
      only have a TypeOrConstraint rather than a full FunTyFlag.  But it's
      very convenient to have the full FunTyFlag, say in mkPiTys, so that's
      what we do.

    Note [VarBndrs, ForAllTyBinders, TyConBinders, and visibility]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    * A ForAllTy (used for both types and kinds) contains a ForAllTyBinder.
      Each ForAllTyBinder
          Bndr a tvis
      is equipped with tvis::ForAllTyFlag, which says whether or not arguments
      for this binder should be visible (explicit) in source Haskell.

    * A TyCon contains a list of TyConBinders.  Each TyConBinder
          Bndr a cvis
      is equipped with cvis::TyConBndrVis, which says whether or not type
      and kind arguments for this TyCon should be visible (explicit) in
      source Haskell.

    This table summarises the visibility rules:
    ---------------------------------------------------------------------------------------
    |                                                      Occurrences look like this
    |                             GHC displays type as     in Haskell source code
    |--------------------------------------------------------------------------------------
    | Bndr a tvis :: ForAllTyBinder, in the binder of ForAllTy for a term
    |  tvis :: ForAllTyFlag
    |  tvis = Inferred:            f :: forall {a}. type    Arg not allowed:  f
                                   f :: forall {co}. type   Arg not allowed:  f
    |  tvis = Specified:           f :: forall a. type      Arg optional:     f  or  f @Int
    |  tvis = Required:            f :: forall k -> type    Arg required:     f (type Int)
    |
    | Bndr k cvis :: TyConBinder, in the TyConBinders of a TyCon
    |  cvis :: TyConBndrVis
    |  cvis = AnonTCB:             T :: kind -> kind        Required:            T *
    |  cvis = NamedTCB Inferred:   T :: forall {k}. kind    Arg not allowed:     T
    |                              T :: forall {co}. kind   Arg not allowed:     T
    |  cvis = NamedTCB Specified:  T :: forall k. kind      Arg not allowed[1]:  T
    |  cvis = NamedTCB Required:   T :: forall k -> kind    Required:            T *
    ---------------------------------------------------------------------------------------

    [1] In types, in the Specified case, it would make sense to allow
        optional kind applications, thus (T @*), but we have not
        yet implemented that

    ---- In term declarations ----

    * Inferred.  Function defn, with no signature:  f1 x = x
      We infer f1 :: forall {a}. a -> a, with 'a' Inferred
      It's Inferred because it doesn't appear in any
      user-written signature for f1

    * Specified.  Function defn, with signature (implicit forall):
         f2 :: a -> a; f2 x = x
      So f2 gets the type f2 :: forall a. a -> a, with 'a' Specified
      even though 'a' is not bound in the source code by an explicit forall

    * Specified.  Function defn, with signature (explicit forall):
         f3 :: forall a. a -> a; f3 x = x
      So f3 gets the type f3 :: forall a. a -> a, with 'a' Specified

    * Required.  Function defn, with signature (explicit forall):
         f4 :: forall a -> a -> a; f4 (type _) x = x
      So f4 gets the type f4 :: forall a -> a -> a, with 'a' Required
      This is the experimental RequiredTypeArguments extension,
      see GHC Proposal #281 "Visible forall in types of terms"

    * Inferred.  Function defn, with signature (explicit forall), marked as inferred:
         f5 :: forall {a}. a -> a; f5 x = x
      So f5 gets the type f5 :: forall {a}. a -> a, with 'a' Inferred
      It's Inferred because the user marked it as such, even though it does appear
      in the user-written signature for f5

    * Inferred/Specified.  Function signature with inferred kind polymorphism.
         f6 :: a b -> Int
      So 'f6' gets the type f6 :: forall {k} (a :: k -> Type) (b :: k). a b -> Int
      Here 'k' is Inferred (it's not mentioned in the type),
      but 'a' and 'b' are Specified.

    * Specified.  Function signature with explicit kind polymorphism
         f7 :: a (b :: k) -> Int
      This time 'k' is Specified, because it is mentioned explicitly,
      so we get f7 :: forall (k :: Type) (a :: k -> Type) (b :: k). a b -> Int

    * Similarly pattern synonyms:
      Inferred - from inferred types (e.g. no pattern type signature)
               - or from inferred kind polymorphism

    ---- In type declarations ----

    * Inferred (k)
         data T1 a b = MkT1 (a b)
      Here T1's kind is  T1 :: forall {k:*}. (k->*) -> k -> *
      The kind variable 'k' is Inferred, since it is not mentioned

      Note that 'a' and 'b' correspond to /Anon/ PiTyBinders in T1's kind,
      and Anon binders don't have a visibility flag. (Or you could think
      of Anon having an implicit Required flag.)

    * Specified (k)
         data T2 (a::k->*) b = MkT (a b)
      Here T's kind is  T :: forall (k:*). (k->*) -> k -> *
      The kind variable 'k' is Specified, since it is mentioned in
      the signature.

    * Required (k)
         data T k (a::k->*) b = MkT (a b)
      Here T's kind is  T :: forall k:* -> (k->*) -> k -> *
      The kind is Required, since it bound in a positional way in T's declaration
      Every use of T must be explicitly applied to a kind

    * Inferred (k1), Specified (k)
         data T a b (c :: k) = MkT (a b) (Proxy c)
      Here T's kind is  T :: forall {k1:*} (k:*). (k1->*) -> k1 -> k -> *
      So 'k' is Specified, because it appears explicitly,
      but 'k1' is Inferred, because it does not

    Generally, in the list of TyConBinders for a TyCon,

    * Inferred arguments always come first
    * Specified, Anon and Required can be mixed

    e.g.
      data Foo (a :: Type) :: forall b. (a -> b -> Type) -> Type where ...

    Here Foo's TyConBinders are
       [Required 'a', Specified 'b', Anon]
    and its kind prints as
       Foo :: forall a -> forall b. (a -> b -> Type) -> Type

    See also Note [Required, Specified, and Inferred for types] in GHC.Tc.TyCl

    ---- Printing -----

     We print forall types with enough syntax to tell you their visibility
     flag.  But this is not source Haskell, and these types may not all
     be parsable.

     Specified: a list of Specified binders is written between `forall` and `.`:
                   const :: forall a b. a -> b -> a

     Inferred: like Specified, but every binder is written in braces:
                   f :: forall {k} (a :: k). S k a -> Int

     Required: binders are put between `forall` and `->`:
                  T :: forall k -> *

    ---- Other points -----

    * In classic Haskell, all named binders (that is, the type variables in
      a polymorphic function type f :: forall a. a -> a) have been Inferred.

    * Inferred variables correspond to "generalized" variables from the
      Visible Type Applications paper (ESOP'16).
    -}

    {-
    ************************************************************************
    *                                                                      *
    *                 Type and kind variables                              *
    *                                                                      *
    ************************************************************************
    -}

    tyVarName :: TyVar -> Name
    tyVarName :: Id -> Name
    tyVarName = Id -> Name
    varName

    tyVarKind :: TyVar -> Kind
    tyVarKind :: Id -> Mult
    tyVarKind = Id -> Mult
    varType

    setTyVarUnique :: TyVar -> Unique -> TyVar
    setTyVarUnique :: Id -> Unique -> Id
    setTyVarUnique = Id -> Unique -> Id
    setVarUnique

    setTyVarName :: TyVar -> Name -> TyVar
    setTyVarName :: Id -> Name -> Id
    setTyVarName   = Id -> Name -> Id
    setVarName

    setTyVarKind :: TyVar -> Kind -> TyVar
    setTyVarKind :: Id -> Mult -> Id
    setTyVarKind Id
    tv Mult
    k = Id
    tv {varType = k}

    updateTyVarKind :: (Kind -> Kind) -> TyVar -> TyVar
    updateTyVarKind :: (Mult -> Mult) -> Id -> Id
    updateTyVarKind Mult -> Mult
    update Id
    tv = Id
    tv {varType = update (tyVarKind tv)}

    updateTyVarKindM :: (Monad m) => (Kind -> m Kind) -> TyVar -> m TyVar
    updateTyVarKindM :: forall (m :: * -> *). Monad m => (Mult -> m Mult) -> Id -> m Id
    updateTyVarKindM Mult -> m Mult
    update Id
    tv
      = do { k' <- Mult -> m Mult
    update (Id -> Mult
    tyVarKind Id
    tv)
           ; return $ tv {varType = k'} }

    mkTyVar :: Name -> Kind -> TyVar
    mkTyVar :: Name -> Mult -> Id
    mkTyVar Name
    name Mult
    kind = TyVar { varName :: Name
    varName    = Name
    name
                              , realUnique :: Unique
    realUnique = Name -> Unique
    nameUnique Name
    name
                              , varType :: Mult
    varType  = Mult
    kind
                              }

    mkTcTyVar :: Name -> Kind -> TcTyVarDetails -> TyVar
    mkTcTyVar :: Name -> Mult -> TcTyVarDetails -> Id
    mkTcTyVar Name
    name Mult
    kind TcTyVarDetails
    details
      = -- NB: 'kind' may be a coercion kind; cf, 'GHC.Tc.Utils.TcMType.newMetaCoVar'
        TcTyVar {   varName :: Name
    varName    = Name
    name,
                    realUnique :: Unique
    realUnique = Name -> Unique
    nameUnique Name
    name,
                    varType :: Mult
    varType  = Mult
    kind,
                    tc_tv_details :: TcTyVarDetails
    tc_tv_details = TcTyVarDetails
    details
            }

    tcTyVarDetails :: TyVar -> TcTyVarDetails
    -- See Note [TcTyVars and TyVars in the typechecker] in GHC.Tc.Utils.TcType
    tcTyVarDetails :: Id -> TcTyVarDetails
    tcTyVarDetails (TcTyVar { tc_tv_details :: Id -> TcTyVarDetails
    tc_tv_details = TcTyVarDetails
    details }) = TcTyVarDetails
    details
    -- MP: This should never happen, but it does. Future work is to turn this into a panic.
    tcTyVarDetails (TyVar {})                            = TcTyVarDetails
    HasDebugCallStack => TcTyVarDetails
    vanillaSkolemTvUnk
    tcTyVarDetails Id
    var = String -> SDoc -> TcTyVarDetails
    forall a. HasCallStack => String -> SDoc -> a
    pprPanic String
    "tcTyVarDetails" (Id -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Id
    var SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> SDoc
    dcolon SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> Mult -> SDoc
    pprKind (Id -> Mult
    tyVarKind Id
    var))

    setTcTyVarDetails :: TyVar -> TcTyVarDetails -> TyVar
    setTcTyVarDetails :: Id -> TcTyVarDetails -> Id
    setTcTyVarDetails Id
    tv TcTyVarDetails
    details = Id
    tv { tc_tv_details = details }

    {-
    %************************************************************************
    %*                                                                      *
    \subsection{Ids}
    *                                                                      *
    ************************************************************************
    -}

    idInfo :: HasDebugCallStack => Id -> IdInfo
    idInfo :: HasDebugCallStack => Id -> IdInfo
    idInfo (Id { id_info :: Id -> IdInfo
    id_info = IdInfo
    info }) = IdInfo
    info
    idInfo Id
    other                   = String -> SDoc -> IdInfo
    forall a. HasCallStack => String -> SDoc -> a
    pprPanic String
    "idInfo" (Id -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Id
    other)

    idDetails :: HasCallStack => Id -> IdDetails
    idDetails :: HasCallStack => Id -> IdDetails
    idDetails (Id { id_details :: Id -> IdDetails
    id_details = IdDetails
    details }) = IdDetails
    details
    idDetails Id
    other                         = String -> SDoc -> IdDetails
    forall a. HasCallStack => String -> SDoc -> a
    pprPanic String
    "idDetails" (Id -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Id
    other)

    -- The next three have a 'Var' suffix even though they always build
    -- Ids, because "GHC.Types.Id" uses 'mkGlobalId' etc with different types
    mkGlobalVar :: IdDetails -> Name -> Type -> IdInfo -> Id
    mkGlobalVar :: IdDetails -> Name -> Mult -> IdInfo -> Id
    mkGlobalVar IdDetails
    details Name
    name Mult
    ty IdInfo
    info
      = Name -> Mult -> Mult -> IdScope -> IdDetails -> IdInfo -> Id
    mk_id Name
    name Mult
    manyDataConTy Mult
    ty IdScope
    GlobalId IdDetails
    details IdInfo
    info
      -- There is no support for linear global variables yet. They would require
      -- being checked at link-time, which can be useful, but is not a priority.

    mkLocalVar :: IdDetails -> Name -> Mult -> Type -> IdInfo -> Id
    mkLocalVar :: IdDetails -> Name -> Mult -> Mult -> IdInfo -> Id
    mkLocalVar IdDetails
    details Name
    name Mult
    w Mult
    ty IdInfo
    info
      = Name -> Mult -> Mult -> IdScope -> IdDetails -> IdInfo -> Id
    mk_id Name
    name Mult
    w Mult
    ty (ExportFlag -> IdScope
    LocalId ExportFlag
    NotExported) IdDetails
    details  IdInfo
    info

    mkCoVar :: Name -> Type -> CoVar
    -- Coercion variables have no IdInfo
    mkCoVar :: Name -> Mult -> Id
    mkCoVar Name
    name Mult
    ty = Name -> Mult -> Mult -> IdScope -> IdDetails -> IdInfo -> Id
    mk_id Name
    name Mult
    manyDataConTy Mult
    ty (ExportFlag -> IdScope
    LocalId ExportFlag
    NotExported) IdDetails
    coVarDetails IdInfo
    vanillaIdInfo

    -- | Exported 'Var's will not be removed as dead code
    mkExportedLocalVar :: IdDetails -> Name -> Type -> IdInfo -> Id
    mkExportedLocalVar :: IdDetails -> Name -> Mult -> IdInfo -> Id
    mkExportedLocalVar IdDetails
    details Name
    name Mult
    ty IdInfo
    info
      = Name -> Mult -> Mult -> IdScope -> IdDetails -> IdInfo -> Id
    mk_id Name
    name Mult
    manyDataConTy Mult
    ty (ExportFlag -> IdScope
    LocalId ExportFlag
    Exported) IdDetails
    details IdInfo
    info
      -- There is no support for exporting linear variables. See also [mkGlobalVar]

    mk_id :: Name -> Mult -> Type -> IdScope -> IdDetails -> IdInfo -> Id
    mk_id :: Name -> Mult -> Mult -> IdScope -> IdDetails -> IdInfo -> Id
    mk_id Name
    name !Mult
    w Mult
    ty IdScope
    scope IdDetails
    details IdInfo
    info
      = Id { varName :: Name
    varName    = Name
    name,
             realUnique :: Unique
    realUnique = Name -> Unique
    nameUnique Name
    name,
             varMult :: Mult
    varMult    = Mult
    w,
             varType :: Mult
    varType    = Mult
    ty,
             idScope :: IdScope
    idScope    = IdScope
    scope,
             id_details :: IdDetails
    id_details = IdDetails
    details,
             id_info :: IdInfo
    id_info    = IdInfo
    info }

    -------------------
    lazySetIdInfo :: Id -> IdInfo -> Var
    lazySetIdInfo :: Id -> IdInfo -> Id
    lazySetIdInfo Id
    id IdInfo
    info = Id
    id { id_info = info }

    setIdDetails :: Id -> IdDetails -> Id
    setIdDetails :: Id -> IdDetails -> Id
    setIdDetails Id
    id IdDetails
    details = Id
    id { id_details = details }

    globaliseId :: Id -> Id
    -- ^ If it's a local, make it global
    globaliseId :: Id -> Id
    globaliseId Id
    id = Id
    id { idScope = GlobalId }

    setIdExported :: Id -> Id
    -- ^ Exports the given local 'Id'. Can also be called on global 'Id's, such as data constructors
    -- and class operations, which are born as global 'Id's and automatically exported
    setIdExported :: Id -> Id
    setIdExported id :: Id
    id@(Id { idScope :: Id -> IdScope
    idScope = LocalId {} }) = Id
    id { idScope = LocalId Exported }
    setIdExported id :: Id
    id@(Id { idScope :: Id -> IdScope
    idScope = IdScope
    GlobalId })   = Id
    id
    setIdExported Id
    tv                               = String -> SDoc -> Id
    forall a. HasCallStack => String -> SDoc -> a
    pprPanic String
    "setIdExported" (Id -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Id
    tv)

    setIdNotExported :: Id -> Id
    -- ^ We can only do this to LocalIds
    setIdNotExported :: Id -> Id
    setIdNotExported Id
    id = Bool -> Id -> Id
    forall a. HasCallStack => Bool -> a -> a
    assert (Id -> Bool
    isLocalId Id
    id) (Id -> Id) -> Id -> Id
    forall a b. (a -> b) -> a -> b
    $
                          Id
    id { idScope = LocalId NotExported }

    -----------------------
    updateIdTypeButNotMult :: (Type -> Type) -> Id -> Id
    updateIdTypeButNotMult :: (Mult -> Mult) -> Id -> Id
    updateIdTypeButNotMult Mult -> Mult
    f Id
    id = Id
    id { varType = f (varType id) }

    updateIdTypeAndMult :: (Type -> Type) -> Id -> Id
    updateIdTypeAndMult :: (Mult -> Mult) -> Id -> Id
    updateIdTypeAndMult Mult -> Mult
    f id :: Id
    id@(Id { varType :: Id -> Mult
    varType = Mult
    ty
                                 , varMult :: Id -> Mult
    varMult = Mult
    mult })
      = Id
    id { varType = ty'
           , varMult = mult' }
      where
        !ty' :: Mult
    ty'   = Mult -> Mult
    f Mult
    ty
        !mult' :: Mult
    mult' = Mult -> Mult
    f Mult
    mult
    updateIdTypeAndMult Mult -> Mult
    _ Id
    other = String -> SDoc -> Id
    forall a. HasCallStack => String -> SDoc -> a
    pprPanic String
    "updateIdTypeAndMult" (Id -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Id
    other)

    updateIdTypeAndMultM :: Monad m => (Type -> m Type) -> Id -> m Id
    updateIdTypeAndMultM :: forall (m :: * -> *). Monad m => (Mult -> m Mult) -> Id -> m Id
    updateIdTypeAndMultM Mult -> m Mult
    f id :: Id
    id@(Id { varType :: Id -> Mult
    varType = Mult
    ty
                                  , varMult :: Id -> Mult
    varMult = Mult
    mult })
      = do { !ty' <- Mult -> m Mult
    f Mult
    ty
           ; !mult' <- f mult
           ; return (id { varType = ty', varMult = mult' }) }
    updateIdTypeAndMultM Mult -> m Mult
    _ Id
    other = String -> SDoc -> m Id
    forall a. HasCallStack => String -> SDoc -> a
    pprPanic String
    "updateIdTypeAndMultM" (Id -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Id
    other)

    setIdMult :: Id -> Mult -> Id
    setIdMult :: Id -> Mult -> Id
    setIdMult Id
    id !Mult
    r | Id -> Bool
    isId Id
    id = Id
    id { varMult = r }
                    | Bool
    otherwise = String -> SDoc -> Id
    forall a. HasCallStack => String -> SDoc -> a
    pprPanic String
    "setIdMult" (Id -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Id
    id SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> Mult -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Mult
    r)

    {-
    ************************************************************************
    *                                                                      *
    \subsection{Predicates over variables}
    *                                                                      *
    ************************************************************************
    -}

    -- | Is this a type-level (i.e., computationally irrelevant, thus erasable)
    -- variable? Satisfies @isTyVar = not . isId@.
    isTyVar :: Var -> Bool        -- True of both TyVar and TcTyVar
    isTyVar :: Id -> Bool
    isTyVar (TyVar {})   = Bool
    True
    isTyVar (TcTyVar {}) = Bool
    True
    isTyVar Id
    _            = Bool
    False

    isTcTyVar :: Var -> Bool      -- True of TcTyVar only
    isTcTyVar :: Id -> Bool
    isTcTyVar (TcTyVar {}) = Bool
    True
    isTcTyVar Id
    _            = Bool
    False

    isTyCoVar :: Var -> Bool
    isTyCoVar :: Id -> Bool
    isTyCoVar Id
    v = Id -> Bool
    isTyVar Id
    v Bool -> Bool -> Bool
    || Id -> Bool
    isCoVar Id
    v

    -- | Is this a value-level (i.e., computationally relevant) 'Id'entifier?
    -- Satisfies @isId = not . isTyVar@.
    isId :: Var -> Bool
    isId :: Id -> Bool
    isId (Id {}) = Bool
    True
    isId Id
    _       = Bool
    False

    -- | Is this a coercion variable?
    -- Satisfies @'isId' v ==> 'isCoVar' v == not ('isNonCoVarId' v)@.
    isCoVar :: Var -> Bool
    isCoVar :: Id -> Bool
    isCoVar (Id { id_details :: Id -> IdDetails
    id_details = IdDetails
    details }) = IdDetails -> Bool
    isCoVarDetails IdDetails
    details
    isCoVar Id
    _                             = Bool
    False

    -- | Is this a term variable ('Id') that is /not/ a coercion variable?
    -- Satisfies @'isId' v ==> 'isCoVar' v == not ('isNonCoVarId' v)@.
    isNonCoVarId :: Var -> Bool
    isNonCoVarId :: Id -> Bool
    isNonCoVarId (Id { id_details :: Id -> IdDetails
    id_details = IdDetails
    details }) = Bool -> Bool
    not (IdDetails -> Bool
    isCoVarDetails IdDetails
    details)
    isNonCoVarId Id
    _                             = Bool
    False

    isLocalId :: Var -> Bool
    isLocalId :: Id -> Bool
    isLocalId (Id { idScope :: Id -> IdScope
    idScope = LocalId ExportFlag
    _ }) = Bool
    True
    isLocalId Id
    _                            = Bool
    False

    isLocalId_maybe :: Var -> Maybe ExportFlag
    isLocalId_maybe :: Id -> Maybe ExportFlag
    isLocalId_maybe (Id { idScope :: Id -> IdScope
    idScope = LocalId ExportFlag
    ef }) = ExportFlag -> Maybe ExportFlag
    forall a. a -> Maybe a
    Just ExportFlag
    ef
    isLocalId_maybe Id
    _                             = Maybe ExportFlag
    forall a. Maybe a
    Nothing

    -- | 'isLocalVar' returns @True@ for type variables as well as local 'Id's
    -- These are the variables that we need to pay attention to when finding free
    -- variables, or doing dependency analysis.
    isLocalVar :: Var -> Bool
    isLocalVar :: Id -> Bool
    isLocalVar Id
    v = Bool -> Bool
    not (Id -> Bool
    isGlobalId Id
    v)

    isGlobalId :: Var -> Bool
    isGlobalId :: Id -> Bool
    isGlobalId (Id { idScope :: Id -> IdScope
    idScope = IdScope
    GlobalId }) = Bool
    True
    isGlobalId Id
    _                           = Bool
    False

    -- | 'mustHaveLocalBinding' returns @True@ of 'Id's and 'TyVar's
    -- that must have a binding in this module.  The converse
    -- is not quite right: there are some global 'Id's that must have
    -- bindings, such as record selectors.  But that doesn't matter,
    -- because it's only used for assertions
    mustHaveLocalBinding        :: Var -> Bool
    mustHaveLocalBinding :: Id -> Bool
    mustHaveLocalBinding Id
    var = Id -> Bool
    isLocalVar Id
    var

    -- | 'isExportedIdVar' means \"don't throw this away\"
    isExportedId :: Var -> Bool
    isExportedId :: Id -> Bool
    isExportedId (Id { idScope :: Id -> IdScope
    idScope = IdScope
    GlobalId })        = Bool
    True
    isExportedId (Id { idScope :: Id -> IdScope
    idScope = LocalId ExportFlag
    Exported}) = Bool
    True
    isExportedId Id
    _ = Bool
    False