prelude/TysWiredIn.hs

    {-
    (c) The GRASP Project, Glasgow University, 1994-1998

    \section[TysWiredIn]{Wired-in knowledge about {\em non-primitive} types}
    -}

    {-# LANGUAGE CPP #-}
    {-# LANGUAGE OverloadedStrings #-}

    -- | This module is about types that can be defined in Haskell, but which
    --   must be wired into the compiler nonetheless.  C.f module TysPrim
    module TysWiredIn (
            -- * Helper functions defined here
            mkWiredInTyConName, -- This is used in TcTypeNats to define the
                                -- built-in functions for evaluation.

            mkWiredInIdName,    -- used in MkId

            mkFunKind, mkForAllKind,

            -- * All wired in things
            wiredInTyCons, isBuiltInOcc_maybe,

            -- * Bool
            boolTy, boolTyCon, boolTyCon_RDR, boolTyConName,
            trueDataCon,  trueDataConId,  true_RDR,
            falseDataCon, falseDataConId, false_RDR,
            promotedFalseDataCon, promotedTrueDataCon,

            -- * Ordering
            orderingTyCon,
            ltDataCon, ltDataConId,
            eqDataCon, eqDataConId,
            gtDataCon, gtDataConId,
            promotedLTDataCon, promotedEQDataCon, promotedGTDataCon,

            -- * Boxing primitive types
            boxingDataCon_maybe,

            -- * Char
            charTyCon, charDataCon, charTyCon_RDR,
            charTy, stringTy, charTyConName,

            -- * Double
            doubleTyCon, doubleDataCon, doubleTy, doubleTyConName,

            -- * Float
            floatTyCon, floatDataCon, floatTy, floatTyConName,

            -- * Int
            intTyCon, intDataCon, intTyCon_RDR, intDataCon_RDR, intTyConName,
            intTy,

            -- * Word
            wordTyCon, wordDataCon, wordTyConName, wordTy,

            -- * Word8
            word8TyCon, word8DataCon, word8TyConName, word8Ty,

            -- * List
            listTyCon, listTyCon_RDR, listTyConName, listTyConKey,
            nilDataCon, nilDataConName, nilDataConKey,
            consDataCon_RDR, consDataCon, consDataConName,
            promotedNilDataCon, promotedConsDataCon,
            mkListTy, mkPromotedListTy,

            -- * Maybe
            maybeTyCon, maybeTyConName,
            nothingDataCon, nothingDataConName, promotedNothingDataCon,
            justDataCon, justDataConName, promotedJustDataCon,

            -- * Tuples
            mkTupleTy, mkBoxedTupleTy,
            tupleTyCon, tupleDataCon, tupleTyConName,
            promotedTupleDataCon,
            unitTyCon, unitDataCon, unitDataConId, unitTy, unitTyConKey,
            pairTyCon,
            unboxedUnitTyCon, unboxedUnitDataCon,
            unboxedTupleKind, unboxedSumKind,

            -- ** Constraint tuples
            cTupleTyConName, cTupleTyConNames, isCTupleTyConName,
            cTupleTyConNameArity_maybe,
            cTupleDataConName, cTupleDataConNames,

            -- * Any
            anyTyCon, anyTy, anyTypeOfKind,

            -- * Sums
            mkSumTy, sumTyCon, sumDataCon,

            -- * Kinds
            typeNatKindCon, typeNatKind, typeSymbolKindCon, typeSymbolKind,
            isLiftedTypeKindTyConName, liftedTypeKind, constraintKind,
            liftedTypeKindTyCon, constraintKindTyCon,
            liftedTypeKindTyConName,

            -- * Equality predicates
            heqTyCon, heqClass, heqDataCon,
            coercibleTyCon, coercibleTyConName, coercibleDataCon, coercibleClass,

            -- * RuntimeRep and friends
            runtimeRepTyCon, vecCountTyCon, vecElemTyCon,

            runtimeRepTy, liftedRepTy, liftedRepDataCon, liftedRepDataConTyCon,

            vecRepDataConTyCon, tupleRepDataConTyCon, sumRepDataConTyCon,

            liftedRepDataConTy, unliftedRepDataConTy, intRepDataConTy,
            wordRepDataConTy, int64RepDataConTy, word64RepDataConTy, addrRepDataConTy,
            floatRepDataConTy, doubleRepDataConTy,

            vec2DataConTy, vec4DataConTy, vec8DataConTy, vec16DataConTy, vec32DataConTy,
            vec64DataConTy,

            int8ElemRepDataConTy, int16ElemRepDataConTy, int32ElemRepDataConTy,
            int64ElemRepDataConTy, word8ElemRepDataConTy, word16ElemRepDataConTy,
            word32ElemRepDataConTy, word64ElemRepDataConTy, floatElemRepDataConTy,
            doubleElemRepDataConTy

        ) where

    #include "HsVersions.h"
    #include "MachDeps.h"

    import GhcPrelude

    import {-# SOURCE #-} MkId( mkDataConWorkId, mkDictSelId )

    -- friends:
    import PrelNames
    import TysPrim
    import {-# SOURCE #-} KnownUniques

    -- others:
    import CoAxiom
    import Id
    import Constants        ( mAX_TUPLE_SIZE, mAX_CTUPLE_SIZE, mAX_SUM_SIZE )
    import Module           ( Module )
    import Type
    import RepType
    import DataCon
    import {-# SOURCE #-} ConLike
    import TyCon
    import Class            ( Class, mkClass )
    import RdrName
    import Name
    import NameEnv          ( NameEnv, mkNameEnv, lookupNameEnv, lookupNameEnv_NF )
    import NameSet          ( NameSet, mkNameSet, elemNameSet )
    import BasicTypes       ( Arity, Boxity(..), TupleSort(..), ConTagZ,
                              SourceText(..) )
    import ForeignCall
    import SrcLoc           ( noSrcSpan )
    import Unique
    import Data.Array
    import FastString
    import Outputable
    import Util
    import BooleanFormula   ( mkAnd )

    import qualified Data.ByteString.Char8 as BS

    import Data.List        ( elemIndex )

    alpha_tyvar :: [TyVar]
    alpha_tyvar = [alphaTyVar]

    alpha_ty :: [Type]
    alpha_ty = [alphaTy]

    {-
    Note [Wiring in RuntimeRep]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~
    The RuntimeRep type (and friends) in GHC.Types has a bunch of constructors,
    making it a pain to wire in. To ease the pain somewhat, we use lists of
    the different bits, like Uniques, Names, DataCons. These lists must be
    kept in sync with each other. The rule is this: use the order as declared
    in GHC.Types. All places where such lists exist should contain a reference
    to this Note, so a search for this Note's name should find all the lists.

    ************************************************************************
    *                                                                      *
    \subsection{Wired in type constructors}
    *                                                                      *
    ************************************************************************

    If you change which things are wired in, make sure you change their
    names in PrelNames, so they use wTcQual, wDataQual, etc
    -}

    -- This list is used only to define PrelInfo.wiredInThings. That in turn
    -- is used to initialise the name environment carried around by the renamer.
    -- This means that if we look up the name of a TyCon (or its implicit binders)
    -- that occurs in this list that name will be assigned the wired-in key we
    -- define here.
    --
    -- Because of their infinite nature, this list excludes tuples, Any and implicit
    -- parameter TyCons (see Note [Built-in syntax and the OrigNameCache]).
    --
    -- See also Note [Known-key names]
    wiredInTyCons :: [TyCon]

    wiredInTyCons = [ -- Units are not treated like other tuples, because then
                      -- are defined in GHC.Base, and there's only a few of them. We
                      -- put them in wiredInTyCons so that they will pre-populate
                      -- the name cache, so the parser in isBuiltInOcc_maybe doesn't
                      -- need to look out for them.
                      unitTyCon
                    , unboxedUnitTyCon
                    , anyTyCon
                    , boolTyCon
                    , charTyCon
                    , doubleTyCon
                    , floatTyCon
                    , intTyCon
                    , wordTyCon
                    , word8TyCon
                    , listTyCon
                    , maybeTyCon
                    , heqTyCon
                    , coercibleTyCon
                    , typeNatKindCon
                    , typeSymbolKindCon
                    , runtimeRepTyCon
                    , vecCountTyCon
                    , vecElemTyCon
                    , constraintKindTyCon
                    , liftedTypeKindTyCon
                    ]

    mkWiredInTyConName :: BuiltInSyntax -> Module -> FastString -> Unique -> TyCon -> Name
    mkWiredInTyConName built_in modu fs unique tycon
      = mkWiredInName modu (mkTcOccFS fs) unique
                      (ATyCon tycon)        -- Relevant TyCon
                      built_in

    mkWiredInDataConName :: BuiltInSyntax -> Module -> FastString -> Unique -> DataCon -> Name
    mkWiredInDataConName built_in modu fs unique datacon
      = mkWiredInName modu (mkDataOccFS fs) unique
                      (AConLike (RealDataCon datacon))    -- Relevant DataCon
                      built_in

    mkWiredInIdName :: Module -> FastString -> Unique -> Id -> Name
    mkWiredInIdName mod fs uniq id
     = mkWiredInName mod (mkOccNameFS Name.varName fs) uniq (AnId id) UserSyntax

    -- See Note [Kind-changing of (~) and Coercible]
    -- in libraries/ghc-prim/GHC/Types.hs
    heqTyConName, heqDataConName, heqSCSelIdName :: Name
    heqTyConName   = mkWiredInTyConName   UserSyntax gHC_TYPES (fsLit "~~")   heqTyConKey      heqTyCon
    heqDataConName = mkWiredInDataConName UserSyntax gHC_TYPES (fsLit "Eq#")  heqDataConKey heqDataCon
    heqSCSelIdName = mkWiredInIdName gHC_TYPES (fsLit "heq_sel") heqSCSelIdKey heqSCSelId

    -- See Note [Kind-changing of (~) and Coercible] in libraries/ghc-prim/GHC/Types.hs
    coercibleTyConName, coercibleDataConName, coercibleSCSelIdName :: Name
    coercibleTyConName   = mkWiredInTyConName   UserSyntax gHC_TYPES (fsLit "Coercible")  coercibleTyConKey   coercibleTyCon
    coercibleDataConName = mkWiredInDataConName UserSyntax gHC_TYPES (fsLit "MkCoercible") coercibleDataConKey coercibleDataCon
    coercibleSCSelIdName = mkWiredInIdName gHC_TYPES (fsLit "coercible_sel") coercibleSCSelIdKey coercibleSCSelId

    charTyConName, charDataConName, intTyConName, intDataConName :: Name
    charTyConName     = mkWiredInTyConName   UserSyntax gHC_TYPES (fsLit "Char") charTyConKey charTyCon
    charDataConName   = mkWiredInDataConName UserSyntax gHC_TYPES (fsLit "C#") charDataConKey charDataCon
    intTyConName      = mkWiredInTyConName   UserSyntax gHC_TYPES (fsLit "Int") intTyConKey   intTyCon
    intDataConName    = mkWiredInDataConName UserSyntax gHC_TYPES (fsLit "I#") intDataConKey  intDataCon

    boolTyConName, falseDataConName, trueDataConName :: Name
    boolTyConName     = mkWiredInTyConName   UserSyntax gHC_TYPES (fsLit "Bool") boolTyConKey boolTyCon
    falseDataConName  = mkWiredInDataConName UserSyntax gHC_TYPES (fsLit "False") falseDataConKey falseDataCon
    trueDataConName   = mkWiredInDataConName UserSyntax gHC_TYPES (fsLit "True")  trueDataConKey  trueDataCon

    listTyConName, nilDataConName, consDataConName :: Name
    listTyConName     = mkWiredInTyConName   BuiltInSyntax gHC_TYPES (fsLit "[]") listTyConKey listTyCon
    nilDataConName    = mkWiredInDataConName BuiltInSyntax gHC_TYPES (fsLit "[]") nilDataConKey nilDataCon
    consDataConName   = mkWiredInDataConName BuiltInSyntax gHC_TYPES (fsLit ":") consDataConKey consDataCon

    maybeTyConName, nothingDataConName, justDataConName :: Name
    maybeTyConName     = mkWiredInTyConName   UserSyntax gHC_MAYBE (fsLit "Maybe")
                                              maybeTyConKey maybeTyCon
    nothingDataConName = mkWiredInDataConName UserSyntax gHC_MAYBE (fsLit "Nothing")
                                              nothingDataConKey nothingDataCon
    justDataConName    = mkWiredInDataConName UserSyntax gHC_MAYBE (fsLit "Just")
                                              justDataConKey justDataCon

    wordTyConName, wordDataConName, word8TyConName, word8DataConName :: Name
    wordTyConName      = mkWiredInTyConName   UserSyntax gHC_TYPES (fsLit "Word")   wordTyConKey     wordTyCon
    wordDataConName    = mkWiredInDataConName UserSyntax gHC_TYPES (fsLit "W#")     wordDataConKey   wordDataCon
    word8TyConName     = mkWiredInTyConName   UserSyntax gHC_WORD  (fsLit "Word8")  word8TyConKey    word8TyCon
    word8DataConName   = mkWiredInDataConName UserSyntax gHC_WORD  (fsLit "W8#")    word8DataConKey  word8DataCon

    floatTyConName, floatDataConName, doubleTyConName, doubleDataConName :: Name
    floatTyConName     = mkWiredInTyConName   UserSyntax gHC_TYPES (fsLit "Float")  floatTyConKey    floatTyCon
    floatDataConName   = mkWiredInDataConName UserSyntax gHC_TYPES (fsLit "F#")     floatDataConKey  floatDataCon
    doubleTyConName    = mkWiredInTyConName   UserSyntax gHC_TYPES (fsLit "Double") doubleTyConKey   doubleTyCon
    doubleDataConName  = mkWiredInDataConName UserSyntax gHC_TYPES (fsLit "D#")     doubleDataConKey doubleDataCon

    -- Any

    {-
    Note [Any types]
    ~~~~~~~~~~~~~~~~
    The type constructor Any,

        type family Any :: k where { }

    It has these properties:

      * Note that 'Any' is kind polymorphic since in some program we may
        need to use Any to fill in a type variable of some kind other than *
        (see #959 for examples).  Its kind is thus `forall k. k``.

      * It is defined in module GHC.Types, and exported so that it is
        available to users.  For this reason it's treated like any other
        wired-in type:
          - has a fixed unique, anyTyConKey,
          - lives in the global name cache

      * It is a *closed* type family, with no instances.  This means that
        if   ty :: '(k1, k2)  we add a given coercion
                 g :: ty ~ (Fst ty, Snd ty)
        If Any was a *data* type, then we'd get inconsistency because 'ty'
        could be (Any '(k1,k2)) and then we'd have an equality with Any on
        one side and '(,) on the other. See also #9097 and #9636.

      * When instantiated at a lifted type it is inhabited by at least one value,
        namely bottom

      * You can safely coerce any /lifted/ type to Any, and back with unsafeCoerce.

      * It does not claim to be a *data* type, and that's important for
        the code generator, because the code gen may *enter* a data value
        but never enters a function value.

      * It is wired-in so we can easily refer to it where we don't have a name
        environment (e.g. see Rules.matchRule for one example)

      * If (Any k) is the type of a value, it must be a /lifted/ value. So
        if we have (Any @(TYPE rr)) then rr must be 'LiftedRep.  See
        Note [TYPE and RuntimeRep] in TysPrim.  This is a convenient
        invariant, and makes isUnliftedTyCon well-defined; otherwise what
        would (isUnliftedTyCon Any) be?

    It's used to instantiate un-constrained type variables after type checking. For
    example, 'length' has type

      length :: forall a. [a] -> Int

    and the list datacon for the empty list has type

      [] :: forall a. [a]

    In order to compose these two terms as @length []@ a type
    application is required, but there is no constraint on the
    choice.  In this situation GHC uses 'Any',

    > length (Any *) ([] (Any *))

    Above, we print kinds explicitly, as if with --fprint-explicit-kinds.

    The Any tycon used to be quite magic, but we have since been able to
    implement it merely with an empty kind polymorphic type family. See #10886 for a
    bit of history.
    -}

    anyTyConName :: Name
    anyTyConName =
        mkWiredInTyConName UserSyntax gHC_TYPES (fsLit "Any") anyTyConKey anyTyCon

    anyTyCon :: TyCon
    anyTyCon = mkFamilyTyCon anyTyConName binders res_kind Nothing
                             (ClosedSynFamilyTyCon Nothing)
                             Nothing
                             NotInjective
      where
        binders@[kv] = mkTemplateKindTyConBinders [liftedTypeKind]
        res_kind = mkTyVarTy (binderVar kv)

    anyTy :: Type
    anyTy = mkTyConTy anyTyCon

    anyTypeOfKind :: Kind -> Type
    anyTypeOfKind kind = mkTyConApp anyTyCon [kind]

    -- Kinds
    typeNatKindConName, typeSymbolKindConName :: Name
    typeNatKindConName    = mkWiredInTyConName UserSyntax gHC_TYPES (fsLit "Nat")    typeNatKindConNameKey    typeNatKindCon
    typeSymbolKindConName = mkWiredInTyConName UserSyntax gHC_TYPES (fsLit "Symbol") typeSymbolKindConNameKey typeSymbolKindCon

    constraintKindTyConName :: Name
    constraintKindTyConName = mkWiredInTyConName UserSyntax gHC_TYPES (fsLit "Constraint") constraintKindTyConKey   constraintKindTyCon

    liftedTypeKindTyConName :: Name
    liftedTypeKindTyConName = mkWiredInTyConName UserSyntax gHC_TYPES (fsLit "Type") liftedTypeKindTyConKey liftedTypeKindTyCon

    runtimeRepTyConName, vecRepDataConName, tupleRepDataConName, sumRepDataConName :: Name
    runtimeRepTyConName = mkWiredInTyConName UserSyntax gHC_TYPES (fsLit "RuntimeRep") runtimeRepTyConKey runtimeRepTyCon
    vecRepDataConName = mkWiredInDataConName UserSyntax gHC_TYPES (fsLit "VecRep") vecRepDataConKey vecRepDataCon
    tupleRepDataConName = mkWiredInDataConName UserSyntax gHC_TYPES (fsLit "TupleRep") tupleRepDataConKey tupleRepDataCon
    sumRepDataConName = mkWiredInDataConName UserSyntax gHC_TYPES (fsLit "SumRep") sumRepDataConKey sumRepDataCon

    -- See Note [Wiring in RuntimeRep]
    runtimeRepSimpleDataConNames :: [Name]
    runtimeRepSimpleDataConNames
      = zipWith3Lazy mk_special_dc_name
          [ fsLit "LiftedRep", fsLit "UnliftedRep"
          , fsLit "IntRep"
          , fsLit "WordRep", fsLit "Int64Rep", fsLit "Word64Rep"
          , fsLit "AddrRep", fsLit "FloatRep", fsLit "DoubleRep" ]
          runtimeRepSimpleDataConKeys
          runtimeRepSimpleDataCons

    vecCountTyConName :: Name
    vecCountTyConName = mkWiredInTyConName UserSyntax gHC_TYPES (fsLit "VecCount") vecCountTyConKey vecCountTyCon

    -- See Note [Wiring in RuntimeRep]
    vecCountDataConNames :: [Name]
    vecCountDataConNames = zipWith3Lazy mk_special_dc_name
                             [ fsLit "Vec2", fsLit "Vec4", fsLit "Vec8"
                             , fsLit "Vec16", fsLit "Vec32", fsLit "Vec64" ]
                             vecCountDataConKeys
                             vecCountDataCons

    vecElemTyConName :: Name
    vecElemTyConName = mkWiredInTyConName UserSyntax gHC_TYPES (fsLit "VecElem") vecElemTyConKey vecElemTyCon

    -- See Note [Wiring in RuntimeRep]
    vecElemDataConNames :: [Name]
    vecElemDataConNames = zipWith3Lazy mk_special_dc_name
                            [ fsLit "Int8ElemRep", fsLit "Int16ElemRep", fsLit "Int32ElemRep"
                            , fsLit "Int64ElemRep", fsLit "Word8ElemRep", fsLit "Word16ElemRep"
                            , fsLit "Word32ElemRep", fsLit "Word64ElemRep"
                            , fsLit "FloatElemRep", fsLit "DoubleElemRep" ]
                            vecElemDataConKeys
                            vecElemDataCons

    mk_special_dc_name :: FastString -> Unique -> DataCon -> Name
    mk_special_dc_name fs u dc = mkWiredInDataConName UserSyntax gHC_TYPES fs u dc

    boolTyCon_RDR, false_RDR, true_RDR, intTyCon_RDR, charTyCon_RDR,
        intDataCon_RDR, listTyCon_RDR, consDataCon_RDR :: RdrName
    boolTyCon_RDR   = nameRdrName boolTyConName
    false_RDR       = nameRdrName falseDataConName
    true_RDR        = nameRdrName trueDataConName
    intTyCon_RDR    = nameRdrName intTyConName
    charTyCon_RDR   = nameRdrName charTyConName
    intDataCon_RDR  = nameRdrName intDataConName
    listTyCon_RDR   = nameRdrName listTyConName
    consDataCon_RDR = nameRdrName consDataConName

    {-
    ************************************************************************
    *                                                                      *
    \subsection{mkWiredInTyCon}
    *                                                                      *
    ************************************************************************
    -}

    -- This function assumes that the types it creates have all parameters at
    -- Representational role, and that there is no kind polymorphism.
    pcTyCon :: Name -> Maybe CType -> [TyVar] -> [DataCon] -> TyCon
    pcTyCon name cType tyvars cons
      = mkAlgTyCon name
                    (mkAnonTyConBinders tyvars)
                    liftedTypeKind
                    (map (const Representational) tyvars)
                    cType
                    []              -- No stupid theta
                    (mkDataTyConRhs cons)
                    (VanillaAlgTyCon (mkPrelTyConRepName name))
                    False           -- Not in GADT syntax

    pcDataCon :: Name -> [TyVar] -> [Type] -> TyCon -> DataCon
    pcDataCon n univs = pcDataConWithFixity False n univs
                          []    -- no ex_tvs
                          univs -- the univs are precisely the user-written tyvars

    pcDataConWithFixity :: Bool      -- ^ declared infix?
                        -> Name      -- ^ datacon name
                        -> [TyVar]   -- ^ univ tyvars
                        -> [TyVar]   -- ^ ex tyvars
                        -> [TyVar]   -- ^ user-written tyvars
                        -> [Type]    -- ^ args
                        -> TyCon
                        -> DataCon
    pcDataConWithFixity infx n = pcDataConWithFixity' infx n (dataConWorkerUnique (nameUnique n))
                                                      NoRRI
    -- The Name's unique is the first of two free uniques;
    -- the first is used for the datacon itself,
    -- the second is used for the "worker name"
    --
    -- To support this the mkPreludeDataConUnique function "allocates"
    -- one DataCon unique per pair of Ints.

    pcDataConWithFixity' :: Bool -> Name -> Unique -> RuntimeRepInfo
                         -> [TyVar] -> [TyVar] -> [TyVar]
                         -> [Type] -> TyCon -> DataCon
    -- The Name should be in the DataName name space; it's the name
    -- of the DataCon itself.

    pcDataConWithFixity' declared_infix dc_name wrk_key rri
                         tyvars ex_tyvars user_tyvars arg_tys tycon
      = data_con
      where
        tag_map = mkTyConTagMap tycon
        -- This constructs the constructor Name to ConTag map once per
        -- constructor, which is quadratic. It's OK here, because it's
        -- only called for wired in data types that don't have a lot of
        -- constructors. It's also likely that GHC will lift tag_map, since
        -- we call pcDataConWithFixity' with static TyCons in the same module.
        -- See Note [Constructor tag allocation] and #14657
        data_con = mkDataCon dc_name declared_infix prom_info
                    (map (const no_bang) arg_tys)
                    []      -- No labelled fields
                    tyvars ex_tyvars
                    (mkTyVarBinders Specified user_tyvars)
                    []      -- No equality spec
                    []      -- No theta
                    arg_tys (mkTyConApp tycon (mkTyVarTys tyvars))
                    rri
                    tycon
                    (lookupNameEnv_NF tag_map dc_name)
                    []      -- No stupid theta
                    (mkDataConWorkId wrk_name data_con)
                    NoDataConRep    -- Wired-in types are too simple to need wrappers

        no_bang = HsSrcBang NoSourceText NoSrcUnpack NoSrcStrict

        wrk_name = mkDataConWorkerName data_con wrk_key

        prom_info = mkPrelTyConRepName dc_name

    mkDataConWorkerName :: DataCon -> Unique -> Name
    mkDataConWorkerName data_con wrk_key =
        mkWiredInName modu wrk_occ wrk_key
                      (AnId (dataConWorkId data_con)) UserSyntax
      where
        modu     = ASSERT( isExternalName dc_name )
                   nameModule dc_name
        dc_name = dataConName data_con
        dc_occ  = nameOccName dc_name
        wrk_occ = mkDataConWorkerOcc dc_occ

    -- used for RuntimeRep and friends
    pcSpecialDataCon :: Name -> [Type] -> TyCon -> RuntimeRepInfo -> DataCon
    pcSpecialDataCon dc_name arg_tys tycon rri
      = pcDataConWithFixity' False dc_name (dataConWorkerUnique (nameUnique dc_name)) rri
                             [] [] [] arg_tys tycon

    {-
    ************************************************************************
    *                                                                      *
          Kinds
    *                                                                      *
    ************************************************************************
    -}

    typeNatKindCon, typeSymbolKindCon :: TyCon
    -- data Nat
    -- data Symbol
    typeNatKindCon    = pcTyCon typeNatKindConName    Nothing [] []
    typeSymbolKindCon = pcTyCon typeSymbolKindConName Nothing [] []

    typeNatKind, typeSymbolKind :: Kind
    typeNatKind    = mkTyConTy typeNatKindCon
    typeSymbolKind = mkTyConTy typeSymbolKindCon

    constraintKindTyCon :: TyCon
    constraintKindTyCon = pcTyCon constraintKindTyConName Nothing [] []

    liftedTypeKind, constraintKind :: Kind
    liftedTypeKind   = tYPE liftedRepTy
    constraintKind   = mkTyConApp constraintKindTyCon []

    -- mkFunKind and mkForAllKind are defined here
    -- solely so that TyCon can use them via a SOURCE import
    mkFunKind :: Kind -> Kind -> Kind
    mkFunKind = mkFunTy

    mkForAllKind :: TyVar -> ArgFlag -> Kind -> Kind
    mkForAllKind = mkForAllTy

    {-
    ************************************************************************
    *                                                                      *
                    Stuff for dealing with tuples
    *                                                                      *
    ************************************************************************

    Note [How tuples work]  See also Note [Known-key names] in PrelNames
    ~~~~~~~~~~~~~~~~~~~~~~
    * There are three families of tuple TyCons and corresponding
      DataCons, expressed by the type BasicTypes.TupleSort:
        data TupleSort = BoxedTuple | UnboxedTuple | ConstraintTuple

    * All three families are AlgTyCons, whose AlgTyConRhs is TupleTyCon

    * BoxedTuples
        - A wired-in type
        - Data type declarations in GHC.Tuple
        - The data constructors really have an info table

    * UnboxedTuples
        - A wired-in type
        - Have a pretend DataCon, defined in GHC.Prim,
          but no actual declaration and no info table

    * ConstraintTuples
        - Are known-key rather than wired-in. Reason: it's awkward to
          have all the superclass selectors wired-in.
        - Declared as classes in GHC.Classes, e.g.
             class (c1,c2) => (c1,c2)
        - Given constraints: the superclasses automatically become available
        - Wanted constraints: there is a built-in instance
             instance (c1,c2) => (c1,c2)
          See TcInteract.matchCTuple
        - Currently just go up to 62; beyond that
          you have to use manual nesting
        - Their OccNames look like (%,,,%), so they can easily be
          distinguished from term tuples.  But (following Haskell) we
          pretty-print saturated constraint tuples with round parens;
          see BasicTypes.tupleParens.

    * In quite a lot of places things are restrcted just to
      BoxedTuple/UnboxedTuple, and then we used BasicTypes.Boxity to distinguish
      E.g. tupleTyCon has a Boxity argument

    * When looking up an OccName in the original-name cache
      (IfaceEnv.lookupOrigNameCache), we spot the tuple OccName to make sure
      we get the right wired-in name.  This guy can't tell the difference
      between BoxedTuple and ConstraintTuple (same OccName!), so tuples
      are not serialised into interface files using OccNames at all.

    * Serialization to interface files works via the usual mechanism for known-key
      things: instead of serializing the OccName we just serialize the key. During
      deserialization we lookup the Name associated with the unique with the logic
      in KnownUniques. See Note [Symbol table representation of names] for details.

    Note [One-tuples]
    ~~~~~~~~~~~~~~~~~
    GHC supports both boxed and unboxed one-tuples:
     - Unboxed one-tuples are sometimes useful when returning a
       single value after CPR analysis
     - A boxed one-tuple is used by DsUtils.mkSelectorBinds, when
       there is just one binder
    Basically it keeps everythig uniform.

    However the /naming/ of the type/data constructors for one-tuples is a
    bit odd:
      3-tuples:  (,,)   (,,)#
      2-tuples:  (,)    (,)#
      1-tuples:  ??
      0-tuples:  ()     ()#

    Zero-tuples have used up the logical name. So we use 'Unit' and 'Unit#'
    for one-tuples.  So in ghc-prim:GHC.Tuple we see the declarations:
      data ()     = ()
      data Unit a = Unit a
      data (a,b)  = (a,b)

    NB (Feb 16): for /constraint/ one-tuples I have 'Unit%' but no class
    decl in GHC.Classes, so I think this part may not work properly. But
    it's unused I think.
    -}

    -- | Built-in syntax isn't "in scope" so these OccNames map to wired-in Names
    -- with BuiltInSyntax. However, this should only be necessary while resolving
    -- names produced by Template Haskell splices since we take care to encode
    -- built-in syntax names specially in interface files. See
    -- Note [Symbol table representation of names].
    --
    -- Moreover, there is no need to include names of things that the user can't
    -- write (e.g. type representation bindings like $tc(,,,)).
    isBuiltInOcc_maybe :: OccName -> Maybe Name
    isBuiltInOcc_maybe occ =
        case name of
          "[]" -> Just $ choose_ns listTyConName nilDataConName
          ":"    -> Just consDataConName

          -- equality tycon
          "~"    -> Just eqTyConName

          -- boxed tuple data/tycon
          "()"    -> Just $ tup_name Boxed 0
          _ | Just rest <- "(" `BS.stripPrefix` name
            , (commas, rest') <- BS.span (==',') rest
            , ")" <- rest'
                 -> Just $ tup_name Boxed (1+BS.length commas)

          -- unboxed tuple data/tycon
          "(##)"  -> Just $ tup_name Unboxed 0
          "Unit#" -> Just $ tup_name Unboxed 1
          _ | Just rest <- "(#" `BS.stripPrefix` name
            , (commas, rest') <- BS.span (==',') rest
            , "#)" <- rest'
                 -> Just $ tup_name Unboxed (1+BS.length commas)

          -- unboxed sum tycon
          _ | Just rest <- "(#" `BS.stripPrefix` name
            , (pipes, rest') <- BS.span (=='|') rest
            , "#)" <- rest'
                 -> Just $ tyConName $ sumTyCon (1+BS.length pipes)

          -- unboxed sum datacon
          _ | Just rest <- "(#" `BS.stripPrefix` name
            , (pipes1, rest') <- BS.span (=='|') rest
            , Just rest'' <- "_" `BS.stripPrefix` rest'
            , (pipes2, rest''') <- BS.span (=='|') rest''
            , "#)" <- rest'''
                 -> let arity = BS.length pipes1 + BS.length pipes2 + 1
                        alt = BS.length pipes1 + 1
                    in Just $ dataConName $ sumDataCon alt arity
          _ -> Nothing
      where
        name = fastStringToByteString $ occNameFS occ

        choose_ns :: Name -> Name -> Name
        choose_ns tc dc
          | isTcClsNameSpace ns   = tc
          | isDataConNameSpace ns = dc
          | otherwise             = pprPanic "tup_name" (ppr occ)
          where ns = occNameSpace occ

        tup_name boxity arity
          = choose_ns (getName (tupleTyCon   boxity arity))
                      (getName (tupleDataCon boxity arity))

    mkTupleOcc :: NameSpace -> Boxity -> Arity -> OccName
    -- No need to cache these, the caching is done in mk_tuple
    mkTupleOcc ns Boxed   ar = mkOccName ns (mkBoxedTupleStr   ar)
    mkTupleOcc ns Unboxed ar = mkOccName ns (mkUnboxedTupleStr ar)

    mkCTupleOcc :: NameSpace -> Arity -> OccName
    mkCTupleOcc ns ar = mkOccName ns (mkConstraintTupleStr ar)

    mkBoxedTupleStr :: Arity -> String
    mkBoxedTupleStr 0  = "()"
    mkBoxedTupleStr 1  = "Unit"   -- See Note [One-tuples]
    mkBoxedTupleStr ar = '(' : commas ar ++ ")"

    mkUnboxedTupleStr :: Arity -> String
    mkUnboxedTupleStr 0  = "(##)"
    mkUnboxedTupleStr 1  = "Unit#"  -- See Note [One-tuples]
    mkUnboxedTupleStr ar = "(#" ++ commas ar ++ "#)"

    mkConstraintTupleStr :: Arity -> String
    mkConstraintTupleStr 0  = "(%%)"
    mkConstraintTupleStr 1  = "Unit%"   -- See Note [One-tuples]
    mkConstraintTupleStr ar = "(%" ++ commas ar ++ "%)"

    commas :: Arity -> String
    commas ar = take (ar-1) (repeat ',')

    cTupleTyConName :: Arity -> Name
    cTupleTyConName arity
      = mkExternalName (mkCTupleTyConUnique arity) gHC_CLASSES
                       (mkCTupleOcc tcName arity) noSrcSpan

    cTupleTyConNames :: [Name]
    cTupleTyConNames = map cTupleTyConName (0 : [2..mAX_CTUPLE_SIZE])

    cTupleTyConNameSet :: NameSet
    cTupleTyConNameSet = mkNameSet cTupleTyConNames

    isCTupleTyConName :: Name -> Bool
    -- Use Type.isCTupleClass where possible
    isCTupleTyConName n
     = ASSERT2( isExternalName n, ppr n )
       nameModule n == gHC_CLASSES
       && n `elemNameSet` cTupleTyConNameSet

    -- | If the given name is that of a constraint tuple, return its arity.
    -- Note that this is inefficient.
    cTupleTyConNameArity_maybe :: Name -> Maybe Arity
    cTupleTyConNameArity_maybe n
      | not (isCTupleTyConName n) = Nothing
      | otherwise = fmap adjustArity (n `elemIndex` cTupleTyConNames)
      where
        -- Since `cTupleTyConNames` jumps straight from the `0` to the `2`
        -- case, we have to adjust accordingly our calculated arity.
        adjustArity a = if a > 0 then a + 1 else a

    cTupleDataConName :: Arity -> Name
    cTupleDataConName arity
      = mkExternalName (mkCTupleDataConUnique arity) gHC_CLASSES
                       (mkCTupleOcc dataName arity) noSrcSpan

    cTupleDataConNames :: [Name]
    cTupleDataConNames = map cTupleDataConName (0 : [2..mAX_CTUPLE_SIZE])

    tupleTyCon :: Boxity -> Arity -> TyCon
    tupleTyCon sort i | i > mAX_TUPLE_SIZE = fst (mk_tuple sort i)  -- Build one specially
    tupleTyCon Boxed   i = fst (boxedTupleArr   ! i)
    tupleTyCon Unboxed i = fst (unboxedTupleArr ! i)

    tupleTyConName :: TupleSort -> Arity -> Name
    tupleTyConName ConstraintTuple a = cTupleTyConName a
    tupleTyConName BoxedTuple      a = tyConName (tupleTyCon Boxed a)
    tupleTyConName UnboxedTuple    a = tyConName (tupleTyCon Unboxed a)

    promotedTupleDataCon :: Boxity -> Arity -> TyCon
    promotedTupleDataCon boxity i = promoteDataCon (tupleDataCon boxity i)

    tupleDataCon :: Boxity -> Arity -> DataCon
    tupleDataCon sort i | i > mAX_TUPLE_SIZE = snd (mk_tuple sort i)    -- Build one specially
    tupleDataCon Boxed   i = snd (boxedTupleArr   ! i)
    tupleDataCon Unboxed i = snd (unboxedTupleArr ! i)

    boxedTupleArr, unboxedTupleArr :: Array Int (TyCon,DataCon)
    boxedTupleArr   = listArray (0,mAX_TUPLE_SIZE) [mk_tuple Boxed   i | i <- [0..mAX_TUPLE_SIZE]]
    unboxedTupleArr = listArray (0,mAX_TUPLE_SIZE) [mk_tuple Unboxed i | i <- [0..mAX_TUPLE_SIZE]]

    -- | Given the TupleRep/SumRep tycon and list of RuntimeReps of the unboxed
    -- tuple/sum arguments, produces the return kind of an unboxed tuple/sum type
    -- constructor. @unboxedTupleSumKind [IntRep, LiftedRep] --> TYPE (TupleRep/SumRep
    -- [IntRep, LiftedRep])@
    unboxedTupleSumKind :: TyCon -> [Type] -> Kind
    unboxedTupleSumKind tc rr_tys
      = tYPE (mkTyConApp tc [mkPromotedListTy runtimeRepTy rr_tys])

    -- | Specialization of 'unboxedTupleSumKind' for tuples
    unboxedTupleKind :: [Type] -> Kind
    unboxedTupleKind = unboxedTupleSumKind tupleRepDataConTyCon

    mk_tuple :: Boxity -> Int -> (TyCon,DataCon)
    mk_tuple Boxed arity = (tycon, tuple_con)
      where
        tycon = mkTupleTyCon tc_name tc_binders tc_res_kind tc_arity tuple_con
                             BoxedTuple flavour

        tc_binders  = mkTemplateAnonTyConBinders (nOfThem arity liftedTypeKind)
        tc_res_kind = liftedTypeKind
        tc_arity    = arity
        flavour     = VanillaAlgTyCon (mkPrelTyConRepName tc_name)

        dc_tvs     = binderVars tc_binders
        dc_arg_tys = mkTyVarTys dc_tvs
        tuple_con  = pcDataCon dc_name dc_tvs dc_arg_tys tycon

        boxity  = Boxed
        modu    = gHC_TUPLE
        tc_name = mkWiredInName modu (mkTupleOcc tcName boxity arity) tc_uniq
                             (ATyCon tycon) BuiltInSyntax
        dc_name = mkWiredInName modu (mkTupleOcc dataName boxity arity) dc_uniq
                                (AConLike (RealDataCon tuple_con)) BuiltInSyntax
        tc_uniq = mkTupleTyConUnique   boxity arity
        dc_uniq = mkTupleDataConUnique boxity arity

    mk_tuple Unboxed arity = (tycon, tuple_con)
      where
        tycon = mkTupleTyCon tc_name tc_binders tc_res_kind tc_arity tuple_con
                             UnboxedTuple flavour

        -- See Note [Unboxed tuple RuntimeRep vars] in TyCon
        -- Kind:  forall (k1:RuntimeRep) (k2:RuntimeRep). TYPE k1 -> TYPE k2 -> #
        tc_binders = mkTemplateTyConBinders (nOfThem arity runtimeRepTy)
                                            (\ks -> map tYPE ks)

        tc_res_kind = unboxedTupleKind rr_tys

        tc_arity    = arity * 2
        flavour     = UnboxedAlgTyCon $ Just (mkPrelTyConRepName tc_name)

        dc_tvs               = binderVars tc_binders
        (rr_tys, dc_arg_tys) = splitAt arity (mkTyVarTys dc_tvs)
        tuple_con            = pcDataCon dc_name dc_tvs dc_arg_tys tycon

        boxity  = Unboxed
        modu    = gHC_PRIM
        tc_name = mkWiredInName modu (mkTupleOcc tcName boxity arity) tc_uniq
                             (ATyCon tycon) BuiltInSyntax
        dc_name = mkWiredInName modu (mkTupleOcc dataName boxity arity) dc_uniq
                                (AConLike (RealDataCon tuple_con)) BuiltInSyntax
        tc_uniq = mkTupleTyConUnique   boxity arity
        dc_uniq = mkTupleDataConUnique boxity arity

    unitTyCon :: TyCon
    unitTyCon = tupleTyCon Boxed 0

    unitTyConKey :: Unique
    unitTyConKey = getUnique unitTyCon

    unitDataCon :: DataCon
    unitDataCon   = head (tyConDataCons unitTyCon)

    unitDataConId :: Id
    unitDataConId = dataConWorkId unitDataCon

    pairTyCon :: TyCon
    pairTyCon = tupleTyCon Boxed 2

    unboxedUnitTyCon :: TyCon
    unboxedUnitTyCon = tupleTyCon Unboxed 0

    unboxedUnitDataCon :: DataCon
    unboxedUnitDataCon = tupleDataCon   Unboxed 0

    {- *********************************************************************
    *                                                                      *
          Unboxed sums
    *                                                                      *
    ********************************************************************* -}

    -- | OccName for n-ary unboxed sum type constructor.
    mkSumTyConOcc :: Arity -> OccName
    mkSumTyConOcc n = mkOccName tcName str
      where
        -- No need to cache these, the caching is done in mk_sum
        str = '(' : '#' : bars ++ "#)"
        bars = replicate (n-1) '|'

    -- | OccName for i-th alternative of n-ary unboxed sum data constructor.
    mkSumDataConOcc :: ConTag -> Arity -> OccName
    mkSumDataConOcc alt n = mkOccName dataName str
      where
        -- No need to cache these, the caching is done in mk_sum
        str = '(' : '#' : bars alt ++ '_' : bars (n - alt - 1) ++ "#)"
        bars i = replicate i '|'

    -- | Type constructor for n-ary unboxed sum.
    sumTyCon :: Arity -> TyCon
    sumTyCon arity
      | arity > mAX_SUM_SIZE
      = fst (mk_sum arity)  -- Build one specially

      | arity < 2
      = panic ("sumTyCon: Arity starts from 2. (arity: " ++ show arity ++ ")")

      | otherwise
      = fst (unboxedSumArr ! arity)

    -- | Data constructor for i-th alternative of a n-ary unboxed sum.
    sumDataCon :: ConTag -- Alternative
               -> Arity  -- Arity
               -> DataCon
    sumDataCon alt arity
      | alt > arity
      = panic ("sumDataCon: index out of bounds: alt: "
               ++ show alt ++ " > arity " ++ show arity)

      | alt <= 0
      = panic ("sumDataCon: Alts start from 1. (alt: " ++ show alt
               ++ ", arity: " ++ show arity ++ ")")

      | arity < 2
      = panic ("sumDataCon: Arity starts from 2. (alt: " ++ show alt
               ++ ", arity: " ++ show arity ++ ")")

      | arity > mAX_SUM_SIZE
      = snd (mk_sum arity) ! (alt - 1)  -- Build one specially

      | otherwise
      = snd (unboxedSumArr ! arity) ! (alt - 1)

    -- | Cached type and data constructors for sums. The outer array is
    -- indexed by the arity of the sum and the inner array is indexed by
    -- the alternative.
    unboxedSumArr :: Array Int (TyCon, Array Int DataCon)
    unboxedSumArr = listArray (2,mAX_SUM_SIZE) [mk_sum i | i <- [2..mAX_SUM_SIZE]]

    -- | Specialization of 'unboxedTupleSumKind' for sums
    unboxedSumKind :: [Type] -> Kind
    unboxedSumKind = unboxedTupleSumKind sumRepDataConTyCon

    -- | Create type constructor and data constructors for n-ary unboxed sum.
    mk_sum :: Arity -> (TyCon, Array ConTagZ DataCon)
    mk_sum arity = (tycon, sum_cons)
      where
        tycon   = mkSumTyCon tc_name tc_binders tc_res_kind (arity * 2) tyvars (elems sum_cons)
                             (UnboxedAlgTyCon rep_name)

        -- Unboxed sums are currently not Typeable due to efficiency concerns. See #13276.
        rep_name = Nothing -- Just $ mkPrelTyConRepName tc_name

        tc_binders = mkTemplateTyConBinders (nOfThem arity runtimeRepTy)
                                            (\ks -> map tYPE ks)

        tyvars = binderVars tc_binders

        tc_res_kind = unboxedSumKind rr_tys

        (rr_tys, tyvar_tys) = splitAt arity (mkTyVarTys tyvars)

        tc_name = mkWiredInName gHC_PRIM (mkSumTyConOcc arity) tc_uniq
                                (ATyCon tycon) BuiltInSyntax

        sum_cons = listArray (0,arity-1) [sum_con i | i <- [0..arity-1]]
        sum_con i = let dc = pcDataCon dc_name
                                       tyvars -- univ tyvars
                                       [tyvar_tys !! i] -- arg types
                                       tycon

                        dc_name = mkWiredInName gHC_PRIM
                                                (mkSumDataConOcc i arity)
                                                (dc_uniq i)
                                                (AConLike (RealDataCon dc))
                                                BuiltInSyntax
                    in dc

        tc_uniq   = mkSumTyConUnique   arity
        dc_uniq i = mkSumDataConUnique i arity

    {-
    ************************************************************************
    *                                                                      *
                  Equality types and classes
    *                                                                      *
    ********************************************************************* -}

    -- See Note [The equality types story] in TysPrim
    -- ((~~) :: forall k1 k2 (a :: k1) (b :: k2). a -> b -> Constraint)
    --
    -- It's tempting to put functional dependencies on (~~), but it's not
    -- necessary because the functional-dependency coverage check looks
    -- through superclasses, and (~#) is handled in that check.

    heqTyCon, coercibleTyCon :: TyCon
    heqClass, coercibleClass :: Class
    heqDataCon, coercibleDataCon :: DataCon
    heqSCSelId, coercibleSCSelId :: Id

    (heqTyCon, heqClass, heqDataCon, heqSCSelId)
      = (tycon, klass, datacon, sc_sel_id)
      where
        tycon     = mkClassTyCon heqTyConName binders roles
                                 rhs klass
                                 (mkPrelTyConRepName heqTyConName)
        klass     = mk_class tycon sc_pred sc_sel_id
        datacon   = pcDataCon heqDataConName tvs [sc_pred] tycon

        -- Kind: forall k1 k2. k1 -> k2 -> Constraint
        binders   = mkTemplateTyConBinders [liftedTypeKind, liftedTypeKind] (\ks -> ks)
        roles     = [Nominal, Nominal, Nominal, Nominal]
        rhs       = mkDataTyConRhs [datacon]

        tvs       = binderVars binders
        sc_pred   = mkTyConApp eqPrimTyCon (mkTyVarTys tvs)
        sc_sel_id = mkDictSelId heqSCSelIdName klass

    (coercibleTyCon, coercibleClass, coercibleDataCon, coercibleSCSelId)
      = (tycon, klass, datacon, sc_sel_id)
      where
        tycon     = mkClassTyCon coercibleTyConName binders roles
                                 rhs klass
                                 (mkPrelTyConRepName coercibleTyConName)
        klass     = mk_class tycon sc_pred sc_sel_id
        datacon   = pcDataCon coercibleDataConName tvs [sc_pred] tycon

        -- Kind: forall k. k -> k -> Constraint
        binders   = mkTemplateTyConBinders [liftedTypeKind] (\[k] -> [k,k])
        roles     = [Nominal, Representational, Representational]
        rhs       = mkDataTyConRhs [datacon]

        tvs@[k,a,b] = binderVars binders
        sc_pred     = mkTyConApp eqReprPrimTyCon (mkTyVarTys [k, k, a, b])
        sc_sel_id   = mkDictSelId coercibleSCSelIdName klass

    mk_class :: TyCon -> PredType -> Id -> Class
    mk_class tycon sc_pred sc_sel_id
      = mkClass (tyConName tycon) (tyConTyVars tycon) [] [sc_pred] [sc_sel_id]
                [] [] (mkAnd []) tycon

    {- *********************************************************************
    *                                                                      *
                    Kinds and RuntimeRep
    *                                                                      *
    ********************************************************************* -}

    -- For information about the usage of the following type,
    -- see Note [TYPE and RuntimeRep] in module TysPrim
    runtimeRepTy :: Type
    runtimeRepTy = mkTyConTy runtimeRepTyCon

    -- Type synonyms; see Note [TYPE and RuntimeRep] in TysPrim
    -- type Type = tYPE 'LiftedRep
    liftedTypeKindTyCon :: TyCon
    liftedTypeKindTyCon   = buildSynTyCon liftedTypeKindTyConName
                                           [] liftedTypeKind []
                                           (tYPE liftedRepTy)

    runtimeRepTyCon :: TyCon
    runtimeRepTyCon = pcTyCon runtimeRepTyConName Nothing []
                              (vecRepDataCon : tupleRepDataCon :
                               sumRepDataCon : runtimeRepSimpleDataCons)

    vecRepDataCon :: DataCon
    vecRepDataCon = pcSpecialDataCon vecRepDataConName [ mkTyConTy vecCountTyCon
                                                       , mkTyConTy vecElemTyCon ]
                                     runtimeRepTyCon
                                     (RuntimeRep prim_rep_fun)
      where
        prim_rep_fun [count, elem]
          | VecCount n <- tyConRuntimeRepInfo (tyConAppTyCon count)
          , VecElem  e <- tyConRuntimeRepInfo (tyConAppTyCon elem)
          = [VecRep n e]
        prim_rep_fun args
          = pprPanic "vecRepDataCon" (ppr args)

    vecRepDataConTyCon :: TyCon
    vecRepDataConTyCon = promoteDataCon vecRepDataCon

    tupleRepDataCon :: DataCon
    tupleRepDataCon = pcSpecialDataCon tupleRepDataConName [ mkListTy runtimeRepTy ]
                                       runtimeRepTyCon (RuntimeRep prim_rep_fun)
      where
        prim_rep_fun [rr_ty_list]
          = concatMap (runtimeRepPrimRep doc) rr_tys
          where
            rr_tys = extractPromotedList rr_ty_list
            doc    = text "tupleRepDataCon" <+> ppr rr_tys
        prim_rep_fun args
          = pprPanic "tupleRepDataCon" (ppr args)

    tupleRepDataConTyCon :: TyCon
    tupleRepDataConTyCon = promoteDataCon tupleRepDataCon

    sumRepDataCon :: DataCon
    sumRepDataCon = pcSpecialDataCon sumRepDataConName [ mkListTy runtimeRepTy ]
                                     runtimeRepTyCon (RuntimeRep prim_rep_fun)
      where
        prim_rep_fun [rr_ty_list]
          = map slotPrimRep (ubxSumRepType prim_repss)
          where
            rr_tys     = extractPromotedList rr_ty_list
            doc        = text "sumRepDataCon" <+> ppr rr_tys
            prim_repss = map (runtimeRepPrimRep doc) rr_tys
        prim_rep_fun args
          = pprPanic "sumRepDataCon" (ppr args)

    sumRepDataConTyCon :: TyCon
    sumRepDataConTyCon = promoteDataCon sumRepDataCon

    -- See Note [Wiring in RuntimeRep]
    runtimeRepSimpleDataCons :: [DataCon]
    liftedRepDataCon :: DataCon
    runtimeRepSimpleDataCons@(liftedRepDataCon : _)
      = zipWithLazy mk_runtime_rep_dc
        [ LiftedRep, UnliftedRep, IntRep, WordRep, Int64Rep
        , Word64Rep, AddrRep, FloatRep, DoubleRep ]
        runtimeRepSimpleDataConNames
      where
        mk_runtime_rep_dc primrep name
          = pcSpecialDataCon name [] runtimeRepTyCon (RuntimeRep (\_ -> [primrep]))

    -- See Note [Wiring in RuntimeRep]
    liftedRepDataConTy, unliftedRepDataConTy,
      intRepDataConTy, wordRepDataConTy, int64RepDataConTy,
      word64RepDataConTy, addrRepDataConTy, floatRepDataConTy, doubleRepDataConTy :: Type
    [liftedRepDataConTy, unliftedRepDataConTy,
       intRepDataConTy, wordRepDataConTy, int64RepDataConTy,
       word64RepDataConTy, addrRepDataConTy, floatRepDataConTy, doubleRepDataConTy]
      = map (mkTyConTy . promoteDataCon) runtimeRepSimpleDataCons

    vecCountTyCon :: TyCon
    vecCountTyCon = pcTyCon vecCountTyConName Nothing [] vecCountDataCons

    -- See Note [Wiring in RuntimeRep]
    vecCountDataCons :: [DataCon]
    vecCountDataCons = zipWithLazy mk_vec_count_dc
                         [ 2, 4, 8, 16, 32, 64 ]
                         vecCountDataConNames
      where
        mk_vec_count_dc n name
          = pcSpecialDataCon name [] vecCountTyCon (VecCount n)

    -- See Note [Wiring in RuntimeRep]
    vec2DataConTy, vec4DataConTy, vec8DataConTy, vec16DataConTy, vec32DataConTy,
      vec64DataConTy :: Type
    [vec2DataConTy, vec4DataConTy, vec8DataConTy, vec16DataConTy, vec32DataConTy,
      vec64DataConTy] = map (mkTyConTy . promoteDataCon) vecCountDataCons

    vecElemTyCon :: TyCon
    vecElemTyCon = pcTyCon vecElemTyConName Nothing [] vecElemDataCons

    -- See Note [Wiring in RuntimeRep]
    vecElemDataCons :: [DataCon]
    vecElemDataCons = zipWithLazy mk_vec_elem_dc
                        [ Int8ElemRep, Int16ElemRep, Int32ElemRep, Int64ElemRep
                        , Word8ElemRep, Word16ElemRep, Word32ElemRep, Word64ElemRep
                        , FloatElemRep, DoubleElemRep ]
                        vecElemDataConNames
      where
        mk_vec_elem_dc elem name
          = pcSpecialDataCon name [] vecElemTyCon (VecElem elem)

    -- See Note [Wiring in RuntimeRep]
    int8ElemRepDataConTy, int16ElemRepDataConTy, int32ElemRepDataConTy,
      int64ElemRepDataConTy, word8ElemRepDataConTy, word16ElemRepDataConTy,
      word32ElemRepDataConTy, word64ElemRepDataConTy, floatElemRepDataConTy,
      doubleElemRepDataConTy :: Type
    [int8ElemRepDataConTy, int16ElemRepDataConTy, int32ElemRepDataConTy,
      int64ElemRepDataConTy, word8ElemRepDataConTy, word16ElemRepDataConTy,
      word32ElemRepDataConTy, word64ElemRepDataConTy, floatElemRepDataConTy,
      doubleElemRepDataConTy] = map (mkTyConTy . promoteDataCon)
                                    vecElemDataCons

    liftedRepDataConTyCon :: TyCon
    liftedRepDataConTyCon = promoteDataCon liftedRepDataCon

    -- The type ('LiftedRep)
    liftedRepTy :: Type
    liftedRepTy = mkTyConTy liftedRepDataConTyCon

    {- *********************************************************************
    *                                                                      *
         The boxed primitive types: Char, Int, etc
    *                                                                      *
    ********************************************************************* -}

    boxingDataCon_maybe :: TyCon -> Maybe DataCon
    --    boxingDataCon_maybe Char# = C#
    --    boxingDataCon_maybe Int#  = I#
    --    ... etc ...
    -- See Note [Boxing primitive types]
    boxingDataCon_maybe tc
      = lookupNameEnv boxing_constr_env (tyConName tc)

    boxing_constr_env :: NameEnv DataCon
    boxing_constr_env
      = mkNameEnv [(charPrimTyConName  , charDataCon  )
                  ,(intPrimTyConName   , intDataCon   )
                  ,(wordPrimTyConName  , wordDataCon  )
                  ,(floatPrimTyConName , floatDataCon )
                  ,(doublePrimTyConName, doubleDataCon) ]

    {- Note [Boxing primitive types]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    For a handful of primitive types (Int, Char, Word, Flaot, Double),
    we can readily box and an unboxed version (Int#, Char# etc) using
    the corresponding data constructor.  This is useful in a couple
    of places, notably let-floating -}

    charTy :: Type
    charTy = mkTyConTy charTyCon

    charTyCon :: TyCon
    charTyCon   = pcTyCon charTyConName
                       (Just (CType NoSourceText Nothing
                                      (NoSourceText,fsLit "HsChar")))
                       [] [charDataCon]
    charDataCon :: DataCon
    charDataCon = pcDataCon charDataConName [] [charPrimTy] charTyCon

    stringTy :: Type
    stringTy = mkListTy charTy -- convenience only

    intTy :: Type
    intTy = mkTyConTy intTyCon

    intTyCon :: TyCon
    intTyCon = pcTyCon intTyConName
                   (Just (CType NoSourceText Nothing (NoSourceText,fsLit "HsInt")))
                     [] [intDataCon]
    intDataCon :: DataCon
    intDataCon = pcDataCon intDataConName [] [intPrimTy] intTyCon

    wordTy :: Type
    wordTy = mkTyConTy wordTyCon

    wordTyCon :: TyCon
    wordTyCon = pcTyCon wordTyConName
                (Just (CType NoSourceText Nothing (NoSourceText, fsLit "HsWord")))
                   [] [wordDataCon]
    wordDataCon :: DataCon
    wordDataCon = pcDataCon wordDataConName [] [wordPrimTy] wordTyCon

    word8Ty :: Type
    word8Ty = mkTyConTy word8TyCon

    word8TyCon :: TyCon
    word8TyCon = pcTyCon word8TyConName
                         (Just (CType NoSourceText Nothing
                                (NoSourceText, fsLit "HsWord8"))) []
                         [word8DataCon]
    word8DataCon :: DataCon
    word8DataCon = pcDataCon word8DataConName [] [wordPrimTy] word8TyCon

    floatTy :: Type
    floatTy = mkTyConTy floatTyCon

    floatTyCon :: TyCon
    floatTyCon   = pcTyCon floatTyConName
                          (Just (CType NoSourceText Nothing
                                 (NoSourceText, fsLit "HsFloat"))) []
                          [floatDataCon]
    floatDataCon :: DataCon
    floatDataCon = pcDataCon         floatDataConName [] [floatPrimTy] floatTyCon

    doubleTy :: Type
    doubleTy = mkTyConTy doubleTyCon

    doubleTyCon :: TyCon
    doubleTyCon = pcTyCon doubleTyConName
                          (Just (CType NoSourceText Nothing
                                 (NoSourceText,fsLit "HsDouble"))) []
                          [doubleDataCon]

    doubleDataCon :: DataCon
    doubleDataCon = pcDataCon doubleDataConName [] [doublePrimTy] doubleTyCon

    {-
    ************************************************************************
    *                                                                      *
                  The Bool type
    *                                                                      *
    ************************************************************************

    An ordinary enumeration type, but deeply wired in.  There are no
    magical operations on @Bool@ (just the regular Prelude code).

    {\em BEGIN IDLE SPECULATION BY SIMON}

    This is not the only way to encode @Bool@.  A more obvious coding makes
    @Bool@ just a boxed up version of @Bool#@, like this:
    \begin{verbatim}
    type Bool# = Int#
    data Bool = MkBool Bool#
    \end{verbatim}

    Unfortunately, this doesn't correspond to what the Report says @Bool@
    looks like!  Furthermore, we get slightly less efficient code (I
    think) with this coding. @gtInt@ would look like this:

    \begin{verbatim}
    gtInt :: Int -> Int -> Bool
    gtInt x y = case x of I# x# ->
                case y of I# y# ->
                case (gtIntPrim x# y#) of
                    b# -> MkBool b#
    \end{verbatim}

    Notice that the result of the @gtIntPrim@ comparison has to be turned
    into an integer (here called @b#@), and returned in a @MkBool@ box.

    The @if@ expression would compile to this:
    \begin{verbatim}
    case (gtInt x y) of
      MkBool b# -> case b# of { 1# -> e1; 0# -> e2 }
    \end{verbatim}

    I think this code is a little less efficient than the previous code,
    but I'm not certain.  At all events, corresponding with the Report is
    important.  The interesting thing is that the language is expressive
    enough to describe more than one alternative; and that a type doesn't
    necessarily need to be a straightforwardly boxed version of its
    primitive counterpart.

    {\em END IDLE SPECULATION BY SIMON}
    -}

    boolTy :: Type
    boolTy = mkTyConTy boolTyCon

    boolTyCon :: TyCon
    boolTyCon = pcTyCon boolTyConName
                        (Just (CType NoSourceText Nothing
                               (NoSourceText, fsLit "HsBool")))
                        [] [falseDataCon, trueDataCon]

    falseDataCon, trueDataCon :: DataCon
    falseDataCon = pcDataCon falseDataConName [] [] boolTyCon
    trueDataCon  = pcDataCon trueDataConName  [] [] boolTyCon

    falseDataConId, trueDataConId :: Id
    falseDataConId = dataConWorkId falseDataCon
    trueDataConId  = dataConWorkId trueDataCon

    orderingTyCon :: TyCon
    orderingTyCon = pcTyCon orderingTyConName Nothing
                            [] [ltDataCon, eqDataCon, gtDataCon]

    ltDataCon, eqDataCon, gtDataCon :: DataCon
    ltDataCon = pcDataCon ltDataConName  [] [] orderingTyCon
    eqDataCon = pcDataCon eqDataConName  [] [] orderingTyCon
    gtDataCon = pcDataCon gtDataConName  [] [] orderingTyCon

    ltDataConId, eqDataConId, gtDataConId :: Id
    ltDataConId = dataConWorkId ltDataCon
    eqDataConId = dataConWorkId eqDataCon
    gtDataConId = dataConWorkId gtDataCon

    {-
    ************************************************************************
    *                                                                      *
                The List type
       Special syntax, deeply wired in,
       but otherwise an ordinary algebraic data type
    *                                                                      *
    ************************************************************************

           data [] a = [] | a : (List a)
    -}

    mkListTy :: Type -> Type
    mkListTy ty = mkTyConApp listTyCon [ty]

    listTyCon :: TyCon
    listTyCon =
      buildAlgTyCon listTyConName alpha_tyvar [Representational]
                    Nothing []
                    (mkDataTyConRhs [nilDataCon, consDataCon])
                    False
                    (VanillaAlgTyCon $ mkPrelTyConRepName listTyConName)

    nilDataCon :: DataCon
    nilDataCon  = pcDataCon nilDataConName alpha_tyvar [] listTyCon

    consDataCon :: DataCon
    consDataCon = pcDataConWithFixity True {- Declared infix -}
                   consDataConName
                   alpha_tyvar [] alpha_tyvar
                   [alphaTy, mkTyConApp listTyCon alpha_ty] listTyCon
    -- Interesting: polymorphic recursion would help here.
    -- We can't use (mkListTy alphaTy) in the defn of consDataCon, else mkListTy
    -- gets the over-specific type (Type -> Type)

    -- Wired-in type Maybe

    maybeTyCon :: TyCon
    maybeTyCon = pcTyCon maybeTyConName Nothing alpha_tyvar
                         [nothingDataCon, justDataCon]

    nothingDataCon :: DataCon
    nothingDataCon = pcDataCon nothingDataConName alpha_tyvar [] maybeTyCon

    justDataCon :: DataCon
    justDataCon = pcDataCon justDataConName alpha_tyvar [alphaTy] maybeTyCon

    {-
    ** *********************************************************************
    *                                                                      *
                The tuple types
    *                                                                      *
    ************************************************************************

    The tuple types are definitely magic, because they form an infinite
    family.

    \begin{itemize}
    \item
    They have a special family of type constructors, of type @TyCon@
    These contain the tycon arity, but don't require a Unique.

    \item
    They have a special family of constructors, of type
    @Id@. Again these contain their arity but don't need a Unique.

    \item
    There should be a magic way of generating the info tables and
    entry code for all tuples.

    But at the moment we just compile a Haskell source
    file\srcloc{lib/prelude/...} containing declarations like:
    \begin{verbatim}
    data Tuple0             = Tup0
    data Tuple2  a b        = Tup2  a b
    data Tuple3  a b c      = Tup3  a b c
    data Tuple4  a b c d    = Tup4  a b c d
    ...
    \end{verbatim}
    The print-names associated with the magic @Id@s for tuple constructors
    ``just happen'' to be the same as those generated by these
    declarations.

    \item
    The instance environment should have a magic way to know
    that each tuple type is an instances of classes @Eq@, @Ix@, @Ord@ and
    so on. \ToDo{Not implemented yet.}

    \item
    There should also be a way to generate the appropriate code for each
    of these instances, but (like the info tables and entry code) it is
    done by enumeration\srcloc{lib/prelude/InTup?.hs}.
    \end{itemize}
    -}

    -- | Make a tuple type. The list of types should /not/ include any
    -- RuntimeRep specifications.
    mkTupleTy :: Boxity -> [Type] -> Type
    -- Special case for *boxed* 1-tuples, which are represented by the type itself
    mkTupleTy Boxed   [ty] = ty
    mkTupleTy Boxed   tys  = mkTyConApp (tupleTyCon Boxed (length tys)) tys
    mkTupleTy Unboxed tys  = mkTyConApp (tupleTyCon Unboxed (length tys))
                                            (map getRuntimeRep tys ++ tys)

    -- | Build the type of a small tuple that holds the specified type of thing
    mkBoxedTupleTy :: [Type] -> Type
    mkBoxedTupleTy tys = mkTupleTy Boxed tys

    unitTy :: Type
    unitTy = mkTupleTy Boxed []

    {- *********************************************************************
    *                                                                      *
                The sum types
    *                                                                      *
    ************************************************************************
    -}

    mkSumTy :: [Type] -> Type
    mkSumTy tys = mkTyConApp (sumTyCon (length tys))
                             (map getRuntimeRep tys ++ tys)

    -- Promoted Booleans

    promotedFalseDataCon, promotedTrueDataCon :: TyCon
    promotedTrueDataCon   = promoteDataCon trueDataCon
    promotedFalseDataCon  = promoteDataCon falseDataCon

    -- Promoted Maybe
    promotedNothingDataCon, promotedJustDataCon :: TyCon
    promotedNothingDataCon = promoteDataCon nothingDataCon
    promotedJustDataCon    = promoteDataCon justDataCon

    -- Promoted Ordering

    promotedLTDataCon
      , promotedEQDataCon
      , promotedGTDataCon
      :: TyCon
    promotedLTDataCon     = promoteDataCon ltDataCon
    promotedEQDataCon     = promoteDataCon eqDataCon
    promotedGTDataCon     = promoteDataCon gtDataCon

    -- Promoted List
    promotedConsDataCon, promotedNilDataCon :: TyCon
    promotedConsDataCon   = promoteDataCon consDataCon
    promotedNilDataCon    = promoteDataCon nilDataCon

    -- | Make a *promoted* list.
    mkPromotedListTy :: Kind   -- ^ of the elements of the list
                     -> [Type] -- ^ elements
                     -> Type
    mkPromotedListTy k tys
      = foldr cons nil tys
      where
        cons :: Type  -- element
             -> Type  -- list
             -> Type
        cons elt list = mkTyConApp promotedConsDataCon [k, elt, list]

        nil :: Type
        nil = mkTyConApp promotedNilDataCon [k]

    -- | Extract the elements of a promoted list. Panics if the type is not a
    -- promoted list
    extractPromotedList :: Type    -- ^ The promoted list
                        -> [Type]
    extractPromotedList tys = go tys
      where
        go list_ty
          | Just (tc, [_k, t, ts]) <- splitTyConApp_maybe list_ty
          = ASSERT( tc `hasKey` consDataConKey )
            t : go ts

          | Just (tc, [_k]) <- splitTyConApp_maybe list_ty
          = ASSERT( tc `hasKey` nilDataConKey )
            []

          | otherwise
          = pprPanic "extractPromotedList" (ppr tys)