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

    {-# LANGUAGE CPP #-}

    {-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-}

    module GHC.Tc.TyCl.Build (
            buildDataCon,
            buildPatSyn,
            TcMethInfo, MethInfo, buildClass,
            mkNewTyConRhs,
            newImplicitBinder, newTyConRepName
        ) where

    #include "HsVersions.h"

    import GHC.Prelude

    import GHC.Iface.Env
    import GHC.Core.FamInstEnv( FamInstEnvs, mkNewTypeCoAxiom )
    import GHC.Builtin.Types( isCTupleTyConName, unboxedUnitTy )
    import GHC.Core.DataCon
    import GHC.Core.PatSyn
    import GHC.Types.Var
    import GHC.Types.Var.Set
    import GHC.Types.Basic
    import GHC.Types.Name
    import GHC.Types.Name.Env
    import GHC.Types.Id.Make
    import GHC.Core.Class
    import GHC.Core.TyCon
    import GHC.Core.Type
    import GHC.Types.SourceText
    import GHC.Tc.Utils.TcType
    import GHC.Core.Multiplicity

    import GHC.Types.SrcLoc( SrcSpan, noSrcSpan )
    import GHC.Driver.Session
    import GHC.Tc.Utils.Monad
    import GHC.Types.Unique.Supply
    import GHC.Utils.Misc
    import GHC.Utils.Outputable
    import GHC.Utils.Panic

    mkNewTyConRhs :: Name -> TyCon -> DataCon -> TcRnIf m n AlgTyConRhs
    -- ^ Monadic because it makes a Name for the coercion TyCon
    --   We pass the Name of the parent TyCon, as well as the TyCon itself,
    --   because the latter is part of a knot, whereas the former is not.
    mkNewTyConRhs :: forall m n. Name -> TyCon -> DataCon -> TcRnIf m n AlgTyConRhs
    mkNewTyConRhs Name
    tycon_name TyCon
    tycon DataCon
    con
      = do  { Name
    co_tycon_name <- forall m n. Name -> (OccName -> OccName) -> TcRnIf m n Name
    newImplicitBinder Name
    tycon_name OccName -> OccName
    mkNewTyCoOcc
            ; let nt_ax :: CoAxiom Unbranched
    nt_ax = Name -> TyCon -> [TyVar] -> [Role] -> Type -> CoAxiom Unbranched
    mkNewTypeCoAxiom Name
    co_tycon_name TyCon
    tycon [TyVar]
    etad_tvs [Role]
    etad_roles Type
    etad_rhs
            ; forall m n. SDoc -> TcRnIf m n ()
    traceIf (String -> SDoc
    text String
    "mkNewTyConRhs" SDoc -> SDoc -> SDoc
    <+> forall a. Outputable a => a -> SDoc
    ppr CoAxiom Unbranched
    nt_ax)
            ; forall (m :: * -> *) a. Monad m => a -> m a
    return (NewTyCon { data_con :: DataCon
    data_con    = DataCon
    con,
                                 nt_rhs :: Type
    nt_rhs      = Type
    rhs_ty,
                                 nt_etad_rhs :: ([TyVar], Type)
    nt_etad_rhs = ([TyVar]
    etad_tvs, Type
    etad_rhs),
                                 nt_co :: CoAxiom Unbranched
    nt_co       = CoAxiom Unbranched
    nt_ax,
                                 nt_lev_poly :: Bool
    nt_lev_poly = Type -> Bool
    isKindLevPoly Type
    res_kind } ) }
                                 -- Coreview looks through newtypes with a Nothing
                                 -- for nt_co, or uses explicit coercions otherwise
      where
        tvs :: [TyVar]
    tvs      = TyCon -> [TyVar]
    tyConTyVars TyCon
    tycon
        roles :: [Role]
    roles    = TyCon -> [Role]
    tyConRoles TyCon
    tycon
        res_kind :: Type
    res_kind = TyCon -> Type
    tyConResKind TyCon
    tycon
        con_arg_ty :: Type
    con_arg_ty = case DataCon -> [Scaled Type]
    dataConRepArgTys DataCon
    con of
                       [Scaled Type
    arg_ty] -> forall a. Scaled a -> a
    scaledThing Scaled Type
    arg_ty
                       [Scaled Type]
    tys -> forall a. HasCallStack => String -> SDoc -> a
    pprPanic String
    "mkNewTyConRhs" (forall a. Outputable a => a -> SDoc
    ppr DataCon
    con SDoc -> SDoc -> SDoc
    <+> forall a. Outputable a => a -> SDoc
    ppr [Scaled Type]
    tys)
        rhs_ty :: Type
    rhs_ty = HasCallStack => [TyVar] -> ThetaType -> Type -> Type
    substTyWith (DataCon -> [TyVar]
    dataConUnivTyVars DataCon
    con)
                             ([TyVar] -> ThetaType
    mkTyVarTys [TyVar]
    tvs) Type
    con_arg_ty
            -- Instantiate the newtype's RHS with the
            -- type variables from the tycon
            -- NB: a newtype DataCon has a type that must look like
            --        forall tvs.  <arg-ty> -> T tvs
            -- Note that we *can't* use dataConInstOrigArgTys here because
            -- the newtype arising from   class Foo a => Bar a where {}
            -- has a single argument (Foo a) that is a *type class*, so
            -- dataConInstOrigArgTys returns [].

        etad_tvs   :: [TyVar]  -- Matched lazily, so that mkNewTypeCo can
        etad_roles :: [Role]   -- return a TyCon without pulling on rhs_ty
        etad_rhs   :: Type     -- See Note [Tricky iface loop] in GHC.Iface.Load
        ([TyVar]
    etad_tvs, [Role]
    etad_roles, Type
    etad_rhs) = [TyVar] -> [Role] -> Type -> ([TyVar], [Role], Type)
    eta_reduce (forall a. [a] -> [a]
    reverse [TyVar]
    tvs) (forall a. [a] -> [a]
    reverse [Role]
    roles) Type
    rhs_ty

        eta_reduce :: [TyVar]       -- Reversed
                   -> [Role]        -- also reversed
                   -> Type          -- Rhs type
                   -> ([TyVar], [Role], Type)  -- Eta-reduced version
                                               -- (tyvars in normal order)
        eta_reduce :: [TyVar] -> [Role] -> Type -> ([TyVar], [Role], Type)
    eta_reduce (TyVar
    a:[TyVar]
    as) (Role
    _:[Role]
    rs) Type
    ty | Just (Type
    fun, Type
    arg) <- Type -> Maybe (Type, Type)
    splitAppTy_maybe Type
    ty,
                                      Just TyVar
    tv <- Type -> Maybe TyVar
    getTyVar_maybe Type
    arg,
                                      TyVar
    tv forall a. Eq a => a -> a -> Bool
    == TyVar
    a,
                                      Bool -> Bool
    not (TyVar
    a TyVar -> VarSet -> Bool
    `elemVarSet` Type -> VarSet
    tyCoVarsOfType Type
    fun)
                                    = [TyVar] -> [Role] -> Type -> ([TyVar], [Role], Type)
    eta_reduce [TyVar]
    as [Role]
    rs Type
    fun
        eta_reduce [TyVar]
    tvs [Role]
    rs Type
    ty = (forall a. [a] -> [a]
    reverse [TyVar]
    tvs, forall a. [a] -> [a]
    reverse [Role]
    rs, Type
    ty)

    ------------------------------------------------------
    buildDataCon :: FamInstEnvs
                -> Name
                -> Bool                     -- Declared infix
                -> TyConRepName
                -> [HsSrcBang]
                -> Maybe [HsImplBang]
                    -- See Note [Bangs on imported data constructors] in GHC.Types.Id.Make
               -> [FieldLabel]             -- Field labels
               -> [TyVar]                  -- Universals
               -> [TyCoVar]                -- Existentials
               -> [InvisTVBinder]          -- User-written 'TyVarBinder's
               -> [EqSpec]                 -- Equality spec
               -> KnotTied ThetaType       -- Does not include the "stupid theta"
                                           -- or the GADT equalities
               -> [KnotTied (Scaled Type)] -- Arguments
               -> KnotTied Type            -- Result types
               -> KnotTied TyCon           -- Rep tycon
               -> NameEnv ConTag           -- Maps the Name of each DataCon to its
                                           -- ConTag
               -> TcRnIf m n DataCon
    -- A wrapper for DataCon.mkDataCon that
    --   a) makes the worker Id
    --   b) makes the wrapper Id if necessary, including
    --      allocating its unique (hence monadic)
    buildDataCon :: forall m n.
    FamInstEnvs
    -> Name
    -> Bool
    -> Name
    -> [HsSrcBang]
    -> Maybe [HsImplBang]
    -> [FieldLabel]
    -> [TyVar]
    -> [TyVar]
    -> [InvisTVBinder]
    -> [EqSpec]
    -> ThetaType
    -> [Scaled Type]
    -> Type
    -> TyCon
    -> NameEnv ConTag
    -> TcRnIf m n DataCon
    buildDataCon FamInstEnvs
    fam_envs Name
    src_name Bool
    declared_infix Name
    prom_info [HsSrcBang]
    src_bangs Maybe [HsImplBang]
    impl_bangs
                 [FieldLabel]
    field_lbls [TyVar]
    univ_tvs [TyVar]
    ex_tvs [InvisTVBinder]
    user_tvbs [EqSpec]
    eq_spec ThetaType
    ctxt [Scaled Type]
    arg_tys Type
    res_ty
                 TyCon
    rep_tycon NameEnv ConTag
    tag_map
      = do  { Name
    wrap_name <- forall m n. Name -> (OccName -> OccName) -> TcRnIf m n Name
    newImplicitBinder Name
    src_name OccName -> OccName
    mkDataConWrapperOcc
            ; Name
    work_name <- forall m n. Name -> (OccName -> OccName) -> TcRnIf m n Name
    newImplicitBinder Name
    src_name OccName -> OccName
    mkDataConWorkerOcc
            -- This last one takes the name of the data constructor in the source
            -- code, which (for Haskell source anyway) will be in the DataName name
            -- space, and puts it into the VarName name space

            ; forall m n. SDoc -> TcRnIf m n ()
    traceIf (String -> SDoc
    text String
    "buildDataCon 1" SDoc -> SDoc -> SDoc
    <+> forall a. Outputable a => a -> SDoc
    ppr Name
    src_name)
            ; UniqSupply
    us <- forall gbl lcl. TcRnIf gbl lcl UniqSupply
    newUniqueSupply
            ; DynFlags
    dflags <- forall (m :: * -> *). HasDynFlags m => m DynFlags
    getDynFlags
            ; let stupid_ctxt :: ThetaType
    stupid_ctxt = TyCon -> ThetaType -> [TyVar] -> ThetaType
    mkDataConStupidTheta TyCon
    rep_tycon (forall a b. (a -> b) -> [a] -> [b]
    map forall a. Scaled a -> a
    scaledThing [Scaled Type]
    arg_tys) [TyVar]
    univ_tvs
                  tag :: ConTag
    tag = forall a. NameEnv a -> Name -> a
    lookupNameEnv_NF NameEnv ConTag
    tag_map Name
    src_name
                  -- See Note [Constructor tag allocation], fixes #14657
                  data_con :: DataCon
    data_con = Name
    -> Bool
    -> Name
    -> [HsSrcBang]
    -> [FieldLabel]
    -> [TyVar]
    -> [TyVar]
    -> [InvisTVBinder]
    -> [EqSpec]
    -> ThetaType
    -> [Scaled Type]
    -> Type
    -> RuntimeRepInfo
    -> TyCon
    -> ConTag
    -> ThetaType
    -> TyVar
    -> DataConRep
    -> DataCon
    mkDataCon Name
    src_name Bool
    declared_infix Name
    prom_info
                                       [HsSrcBang]
    src_bangs [FieldLabel]
    field_lbls
                                       [TyVar]
    univ_tvs [TyVar]
    ex_tvs [InvisTVBinder]
    user_tvbs [EqSpec]
    eq_spec ThetaType
    ctxt
                                       [Scaled Type]
    arg_tys Type
    res_ty RuntimeRepInfo
    NoRRI TyCon
    rep_tycon ConTag
    tag
                                       ThetaType
    stupid_ctxt TyVar
    dc_wrk DataConRep
    dc_rep
                  dc_wrk :: TyVar
    dc_wrk = Name -> DataCon -> TyVar
    mkDataConWorkId Name
    work_name DataCon
    data_con
                  dc_rep :: DataConRep
    dc_rep = forall a. UniqSupply -> UniqSM a -> a
    initUs_ UniqSupply
    us (DynFlags
    -> FamInstEnvs
    -> Name
    -> Maybe [HsImplBang]
    -> DataCon
    -> UniqSM DataConRep
    mkDataConRep DynFlags
    dflags FamInstEnvs
    fam_envs Name
    wrap_name
                                                    Maybe [HsImplBang]
    impl_bangs DataCon
    data_con)

            ; forall m n. SDoc -> TcRnIf m n ()
    traceIf (String -> SDoc
    text String
    "buildDataCon 2" SDoc -> SDoc -> SDoc
    <+> forall a. Outputable a => a -> SDoc
    ppr Name
    src_name)
            ; forall (m :: * -> *) a. Monad m => a -> m a
    return DataCon
    data_con }

    -- The stupid context for a data constructor should be limited to
    -- the type variables mentioned in the arg_tys
    -- ToDo: Or functionally dependent on?
    --       This whole stupid theta thing is, well, stupid.
    mkDataConStupidTheta :: TyCon -> [Type] -> [TyVar] -> [PredType]
    mkDataConStupidTheta :: TyCon -> ThetaType -> [TyVar] -> ThetaType
    mkDataConStupidTheta TyCon
    tycon ThetaType
    arg_tys [TyVar]
    univ_tvs
      | forall (t :: * -> *) a. Foldable t => t a -> Bool
    null ThetaType
    stupid_theta = []      -- The common case
      | Bool
    otherwise         = forall a. (a -> Bool) -> [a] -> [a]
    filter Type -> Bool
    in_arg_tys ThetaType
    stupid_theta
      where
        tc_subst :: TCvSubst
    tc_subst     = HasDebugCallStack => [TyVar] -> ThetaType -> TCvSubst
    zipTvSubst (TyCon -> [TyVar]
    tyConTyVars TyCon
    tycon)
                                  ([TyVar] -> ThetaType
    mkTyVarTys [TyVar]
    univ_tvs)
        stupid_theta :: ThetaType
    stupid_theta = HasCallStack => TCvSubst -> ThetaType -> ThetaType
    substTheta TCvSubst
    tc_subst (TyCon -> ThetaType
    tyConStupidTheta TyCon
    tycon)
            -- Start by instantiating the master copy of the
            -- stupid theta, taken from the TyCon

        arg_tyvars :: VarSet
    arg_tyvars      = ThetaType -> VarSet
    tyCoVarsOfTypes ThetaType
    arg_tys
        in_arg_tys :: Type -> Bool
    in_arg_tys Type
    pred = Type -> VarSet
    tyCoVarsOfType Type
    pred VarSet -> VarSet -> Bool
    `intersectsVarSet` VarSet
    arg_tyvars

    ------------------------------------------------------
    buildPatSyn :: Name -> Bool
                -> PatSynMatcher -> PatSynBuilder
                -> ([InvisTVBinder], ThetaType) -- ^ Univ and req
                -> ([InvisTVBinder], ThetaType) -- ^ Ex and prov
                -> [Type]                       -- ^ Argument types
                -> Type                         -- ^ Result type
                -> [FieldLabel]                 -- ^ Field labels for
                                                --   a record pattern synonym
                -> PatSyn
    buildPatSyn :: Name
    -> Bool
    -> PatSynMatcher
    -> PatSynBuilder
    -> ([InvisTVBinder], ThetaType)
    -> ([InvisTVBinder], ThetaType)
    -> ThetaType
    -> Type
    -> [FieldLabel]
    -> PatSyn
    buildPatSyn Name
    src_name Bool
    declared_infix matcher :: PatSynMatcher
    matcher@(Name
    _, Type
    matcher_ty,Bool
    _) PatSynBuilder
    builder
                ([InvisTVBinder]
    univ_tvs, ThetaType
    req_theta) ([InvisTVBinder]
    ex_tvs, ThetaType
    prov_theta) ThetaType
    arg_tys
                Type
    pat_ty [FieldLabel]
    field_labels
      = -- The assertion checks that the matcher is
        -- compatible with the pattern synonym
        ASSERT2((and [ univ_tvs `equalLength` univ_tvs1
                     , ex_tvs `equalLength` ex_tvs1
                     , pat_ty `eqType` substTy subst (scaledThing pat_ty1)
                     , prov_theta `eqTypes` substTys subst prov_theta1
                     , req_theta `eqTypes` substTys subst req_theta1
                     , compareArgTys arg_tys (substTys subst (map scaledThing arg_tys1))
                     ])
                , (vcat [ ppr univ_tvs <+> twiddle <+> ppr univ_tvs1
                        , ppr ex_tvs <+> twiddle <+> ppr ex_tvs1
                        , ppr pat_ty <+> twiddle <+> ppr pat_ty1
                        , ppr prov_theta <+> twiddle <+> ppr prov_theta1
                        , ppr req_theta <+> twiddle <+> ppr req_theta1
                        , ppr arg_tys <+> twiddle <+> ppr arg_tys1]))
        Name
    -> Bool
    -> ([InvisTVBinder], ThetaType)
    -> ([InvisTVBinder], ThetaType)
    -> ThetaType
    -> Type
    -> PatSynMatcher
    -> PatSynBuilder
    -> [FieldLabel]
    -> PatSyn
    mkPatSyn Name
    src_name Bool
    declared_infix
                 ([InvisTVBinder]
    univ_tvs, ThetaType
    req_theta) ([InvisTVBinder]
    ex_tvs, ThetaType
    prov_theta)
                 ThetaType
    arg_tys Type
    pat_ty
                 PatSynMatcher
    matcher PatSynBuilder
    builder [FieldLabel]
    field_labels
      where
        ((TyVar
    _:TyVar
    _:[TyVar]
    univ_tvs1), ThetaType
    req_theta1, Type
    tau) = Type -> ([TyVar], ThetaType, Type)
    tcSplitSigmaTy forall a b. (a -> b) -> a -> b
    $ Type
    matcher_ty
        ([Scaled Type
    pat_ty1, Scaled Type
    cont_sigma, Scaled Type
    _], Type
    _)      = Type -> ([Scaled Type], Type)
    tcSplitFunTys Type
    tau
        ([TyVar]
    ex_tvs1, ThetaType
    prov_theta1, Type
    cont_tau)   = Type -> ([TyVar], ThetaType, Type)
    tcSplitSigmaTy (forall a. Scaled a -> a
    scaledThing Scaled Type
    cont_sigma)
        ([Scaled Type]
    arg_tys1, Type
    _) = (Type -> ([Scaled Type], Type)
    tcSplitFunTys Type
    cont_tau)
        twiddle :: SDoc
    twiddle = Char -> SDoc
    char Char
    '~'
        subst :: TCvSubst
    subst = HasDebugCallStack => [TyVar] -> ThetaType -> TCvSubst
    zipTvSubst ([TyVar]
    univ_tvs1 forall a. [a] -> [a] -> [a]
    ++ [TyVar]
    ex_tvs1)
                           ([TyVar] -> ThetaType
    mkTyVarTys (forall tv argf. [VarBndr tv argf] -> [tv]
    binderVars ([InvisTVBinder]
    univ_tvs forall a. [a] -> [a] -> [a]
    ++ [InvisTVBinder]
    ex_tvs)))

        -- For a nullary pattern synonym we add a single (# #) argument to the
        -- matcher to preserve laziness in the case of unlifted types.
        -- See #12746
        compareArgTys :: [Type] -> [Type] -> Bool
        compareArgTys :: ThetaType -> ThetaType -> Bool
    compareArgTys [] [Type
    x] = Type
    x Type -> Type -> Bool
    `eqType` Type
    unboxedUnitTy
        compareArgTys ThetaType
    arg_tys ThetaType
    matcher_arg_tys = ThetaType
    arg_tys ThetaType -> ThetaType -> Bool
    `eqTypes` ThetaType
    matcher_arg_tys

    ------------------------------------------------------
    type TcMethInfo = MethInfo  -- this variant needs zonking
    type MethInfo       -- A temporary intermediate, to communicate
                        -- between tcClassSigs and buildClass.
      = ( Name   -- Name of the class op
        , Type   -- Type of the class op
        , Maybe (DefMethSpec (SrcSpan, Type)))
             -- Nothing                    => no default method
             --
             -- Just VanillaDM             => There is an ordinary
             --                               polymorphic default method
             --
             -- Just (GenericDM (loc, ty)) => There is a generic default metho
             --                               Here is its type, and the location
             --                               of the type signature
             --    We need that location /only/ to attach it to the
             --    generic default method's Name; and we need /that/
             --    only to give the right location of an ambiguity error
             --    for the generic default method, spat out by checkValidClass

    buildClass :: Name  -- Name of the class/tycon (they have the same Name)
               -> [TyConBinder]                -- Of the tycon
               -> [Role]
               -> [FunDep TyVar]               -- Functional dependencies
               -- Super classes, associated types, method info, minimal complete def.
               -- This is Nothing if the class is abstract.
               -> Maybe (KnotTied ThetaType, [ClassATItem], [KnotTied MethInfo], ClassMinimalDef)
               -> TcRnIf m n Class

    buildClass :: forall m n.
    Name
    -> [TyConBinder]
    -> [Role]
    -> [FunDep TyVar]
    -> Maybe
         (ThetaType, [ClassATItem], [KnotTied MethInfo], ClassMinimalDef)
    -> TcRnIf m n Class
    buildClass Name
    tycon_name [TyConBinder]
    binders [Role]
    roles [FunDep TyVar]
    fds Maybe
      (ThetaType, [ClassATItem], [KnotTied MethInfo], ClassMinimalDef)
    Nothing
      = forall a env. (a -> IOEnv env a) -> IOEnv env a
    fixM  forall a b. (a -> b) -> a -> b
    $ \ Class
    rec_clas ->       -- Only name generation inside loop
        do  { forall m n. SDoc -> TcRnIf m n ()
    traceIf (String -> SDoc
    text String
    "buildClass")

            ; Name
    tc_rep_name  <- forall gbl lcl. Name -> TcRnIf gbl lcl Name
    newTyConRepName Name
    tycon_name
            ; let univ_tvs :: [TyVar]
    univ_tvs = forall tv argf. [VarBndr tv argf] -> [tv]
    binderVars [TyConBinder]
    binders
                  tycon :: TyCon
    tycon = Name
    -> [TyConBinder] -> [Role] -> AlgTyConRhs -> Class -> Name -> TyCon
    mkClassTyCon Name
    tycon_name [TyConBinder]
    binders [Role]
    roles
                                       AlgTyConRhs
    AbstractTyCon Class
    rec_clas Name
    tc_rep_name
                  result :: Class
    result = Name -> [TyVar] -> [FunDep TyVar] -> TyCon -> Class
    mkAbstractClass Name
    tycon_name [TyVar]
    univ_tvs [FunDep TyVar]
    fds TyCon
    tycon
            ; forall m n. SDoc -> TcRnIf m n ()
    traceIf (String -> SDoc
    text String
    "buildClass" SDoc -> SDoc -> SDoc
    <+> forall a. Outputable a => a -> SDoc
    ppr TyCon
    tycon)
            ; forall (m :: * -> *) a. Monad m => a -> m a
    return Class
    result }

    buildClass Name
    tycon_name [TyConBinder]
    binders [Role]
    roles [FunDep TyVar]
    fds
               (Just (ThetaType
    sc_theta, [ClassATItem]
    at_items, [KnotTied MethInfo]
    sig_stuff, ClassMinimalDef
    mindef))
      = forall a env. (a -> IOEnv env a) -> IOEnv env a
    fixM  forall a b. (a -> b) -> a -> b
    $ \ Class
    rec_clas ->       -- Only name generation inside loop
        do  { forall m n. SDoc -> TcRnIf m n ()
    traceIf (String -> SDoc
    text String
    "buildClass")

            ; Name
    datacon_name <- forall m n. Name -> (OccName -> OccName) -> TcRnIf m n Name
    newImplicitBinder Name
    tycon_name OccName -> OccName
    mkClassDataConOcc
            ; Name
    tc_rep_name  <- forall gbl lcl. Name -> TcRnIf gbl lcl Name
    newTyConRepName Name
    tycon_name

            ; [ClassOpItem]
    op_items <- forall (t :: * -> *) (m :: * -> *) a b.
    (Traversable t, Monad m) =>
    (a -> m b) -> t a -> m (t b)
    mapM (forall n m. Class -> KnotTied MethInfo -> TcRnIf n m ClassOpItem
    mk_op_item Class
    rec_clas) [KnotTied MethInfo]
    sig_stuff
                            -- Build the selector id and default method id

                  -- Make selectors for the superclasses
            ; [Name]
    sc_sel_names <- forall (t :: * -> *) (m :: * -> *) a b.
    (Traversable t, Monad m) =>
    (a -> m b) -> t a -> m (t b)
    mapM  (forall m n. Name -> (OccName -> OccName) -> TcRnIf m n Name
    newImplicitBinder Name
    tycon_name forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ConTag -> OccName -> OccName
    mkSuperDictSelOcc)
                                    (forall b a. [b] -> [a] -> [a]
    takeList ThetaType
    sc_theta [ConTag
    fIRST_TAG..])
            ; let sc_sel_ids :: [TyVar]
    sc_sel_ids = [ Name -> Class -> TyVar
    mkDictSelId Name
    sc_name Class
    rec_clas
                               | Name
    sc_name <- [Name]
    sc_sel_names]
                  -- We number off the Dict superclass selectors, 1, 2, 3 etc so that we
                  -- can construct names for the selectors. Thus
                  --      class (C a, C b) => D a b where ...
                  -- gives superclass selectors
                  --      D_sc1, D_sc2
                  -- (We used to call them D_C, but now we can have two different
                  --  superclasses both called C!)

            ; let use_newtype :: Bool
    use_newtype = forall a. [a] -> Bool
    isSingleton ThetaType
    arg_tys
                    -- Use a newtype if the data constructor
                    --   (a) has exactly one value field
                    --       i.e. exactly one operation or superclass taken together
                    --   (b) that value is of lifted type (which they always are, because
                    --       we box equality superclasses)
                    -- See note [Class newtypes and equality predicates]

                    -- We treat the dictionary superclasses as ordinary arguments.
                    -- That means that in the case of
                    --     class C a => D a
                    -- we don't get a newtype with no arguments!
                  args :: [Name]
    args       = [Name]
    sc_sel_names forall a. [a] -> [a] -> [a]
    ++ [Name]
    op_names
                  op_tys :: ThetaType
    op_tys     = [Type
    ty | (Name
    _,Type
    ty,Maybe (DefMethSpec (SrcSpan, Type))
    _) <- [KnotTied MethInfo]
    sig_stuff]
                  op_names :: [Name]
    op_names   = [Name
    op | (Name
    op,Type
    _,Maybe (DefMethSpec (SrcSpan, Type))
    _) <- [KnotTied MethInfo]
    sig_stuff]
                  arg_tys :: ThetaType
    arg_tys    = ThetaType
    sc_theta forall a. [a] -> [a] -> [a]
    ++ ThetaType
    op_tys
                  rec_tycon :: TyCon
    rec_tycon  = Class -> TyCon
    classTyCon Class
    rec_clas
                  univ_bndrs :: [InvisTVBinder]
    univ_bndrs = [TyConBinder] -> [InvisTVBinder]
    tyConInvisTVBinders [TyConBinder]
    binders
                  univ_tvs :: [TyVar]
    univ_tvs   = forall tv argf. [VarBndr tv argf] -> [tv]
    binderVars [InvisTVBinder]
    univ_bndrs

            ; Name
    rep_nm   <- forall gbl lcl. Name -> TcRnIf gbl lcl Name
    newTyConRepName Name
    datacon_name
            ; DataCon
    dict_con <- forall m n.
    FamInstEnvs
    -> Name
    -> Bool
    -> Name
    -> [HsSrcBang]
    -> Maybe [HsImplBang]
    -> [FieldLabel]
    -> [TyVar]
    -> [TyVar]
    -> [InvisTVBinder]
    -> [EqSpec]
    -> ThetaType
    -> [Scaled Type]
    -> Type
    -> TyCon
    -> NameEnv ConTag
    -> TcRnIf m n DataCon
    buildDataCon (forall a. String -> a
    panic String
    "buildClass: FamInstEnvs")
                                       Name
    datacon_name
                                       Bool
    False        -- Not declared infix
                                       Name
    rep_nm
                                       (forall a b. (a -> b) -> [a] -> [b]
    map (forall a b. a -> b -> a
    const HsSrcBang
    no_bang) [Name]
    args)
                                       (forall a. a -> Maybe a
    Just (forall a b. (a -> b) -> [a] -> [b]
    map (forall a b. a -> b -> a
    const HsImplBang
    HsLazy) [Name]
    args))
                                       [{- No fields -}]
                                       [TyVar]
    univ_tvs
                                       [{- no existentials -}]
                                       [InvisTVBinder]
    univ_bndrs
                                       [{- No GADT equalities -}]
                                       [{- No theta -}]
                                       (forall a b. (a -> b) -> [a] -> [b]
    map forall a. a -> Scaled a
    unrestricted ThetaType
    arg_tys) -- type classes are unrestricted
                                       (TyCon -> ThetaType -> Type
    mkTyConApp TyCon
    rec_tycon ([TyVar] -> ThetaType
    mkTyVarTys [TyVar]
    univ_tvs))
                                       TyCon
    rec_tycon
                                       (TyCon -> NameEnv ConTag
    mkTyConTagMap TyCon
    rec_tycon)

            ; AlgTyConRhs
    rhs <- case () of
                      ()
    _ | Bool
    use_newtype
                        -> forall m n. Name -> TyCon -> DataCon -> TcRnIf m n AlgTyConRhs
    mkNewTyConRhs Name
    tycon_name TyCon
    rec_tycon DataCon
    dict_con
                        | Name -> Bool
    isCTupleTyConName Name
    tycon_name
                        -> forall (m :: * -> *) a. Monad m => a -> m a
    return (TupleTyCon { data_con :: DataCon
    data_con = DataCon
    dict_con
                                              , tup_sort :: TupleSort
    tup_sort = TupleSort
    ConstraintTuple })
                        | Bool
    otherwise
                        -> forall (m :: * -> *) a. Monad m => a -> m a
    return ([DataCon] -> AlgTyConRhs
    mkDataTyConRhs [DataCon
    dict_con])

            ; let { tycon :: TyCon
    tycon = Name
    -> [TyConBinder] -> [Role] -> AlgTyConRhs -> Class -> Name -> TyCon
    mkClassTyCon Name
    tycon_name [TyConBinder]
    binders [Role]
    roles
                                         AlgTyConRhs
    rhs Class
    rec_clas Name
    tc_rep_name
                    -- A class can be recursive, and in the case of newtypes
                    -- this matters.  For example
                    --      class C a where { op :: C b => a -> b -> Int }
                    -- Because C has only one operation, it is represented by
                    -- a newtype, and it should be a *recursive* newtype.
                    -- [If we don't make it a recursive newtype, we'll expand the
                    -- newtype like a synonym, but that will lead to an infinite
                    -- type]

                  ; result :: Class
    result = Name
    -> [TyVar]
    -> [FunDep TyVar]
    -> ThetaType
    -> [TyVar]
    -> [ClassATItem]
    -> [ClassOpItem]
    -> ClassMinimalDef
    -> TyCon
    -> Class
    mkClass Name
    tycon_name [TyVar]
    univ_tvs [FunDep TyVar]
    fds
                                     ThetaType
    sc_theta [TyVar]
    sc_sel_ids [ClassATItem]
    at_items
                                     [ClassOpItem]
    op_items ClassMinimalDef
    mindef TyCon
    tycon
                  }
            ; forall m n. SDoc -> TcRnIf m n ()
    traceIf (String -> SDoc
    text String
    "buildClass" SDoc -> SDoc -> SDoc
    <+> forall a. Outputable a => a -> SDoc
    ppr TyCon
    tycon)
            ; forall (m :: * -> *) a. Monad m => a -> m a
    return Class
    result }
      where
        no_bang :: HsSrcBang
    no_bang = SourceText -> SrcUnpackedness -> SrcStrictness -> HsSrcBang
    HsSrcBang SourceText
    NoSourceText SrcUnpackedness
    NoSrcUnpack SrcStrictness
    NoSrcStrict

        mk_op_item :: Class -> TcMethInfo -> TcRnIf n m ClassOpItem
        mk_op_item :: forall n m. Class -> KnotTied MethInfo -> TcRnIf n m ClassOpItem
    mk_op_item Class
    rec_clas (Name
    op_name, Type
    _, Maybe (DefMethSpec (SrcSpan, Type))
    dm_spec)
          = do { Maybe (Name, DefMethSpec Type)
    dm_info <- forall n m.
    Name
    -> Maybe (DefMethSpec (SrcSpan, Type))
    -> TcRnIf n m (Maybe (Name, DefMethSpec Type))
    mk_dm_info Name
    op_name Maybe (DefMethSpec (SrcSpan, Type))
    dm_spec
               ; forall (m :: * -> *) a. Monad m => a -> m a
    return (Name -> Class -> TyVar
    mkDictSelId Name
    op_name Class
    rec_clas, Maybe (Name, DefMethSpec Type)
    dm_info) }

        mk_dm_info :: Name -> Maybe (DefMethSpec (SrcSpan, Type))
                   -> TcRnIf n m (Maybe (Name, DefMethSpec Type))
        mk_dm_info :: forall n m.
    Name
    -> Maybe (DefMethSpec (SrcSpan, Type))
    -> TcRnIf n m (Maybe (Name, DefMethSpec Type))
    mk_dm_info Name
    _ Maybe (DefMethSpec (SrcSpan, Type))
    Nothing
          = forall (m :: * -> *) a. Monad m => a -> m a
    return forall a. Maybe a
    Nothing
        mk_dm_info Name
    op_name (Just DefMethSpec (SrcSpan, Type)
    VanillaDM)
          = do { Name
    dm_name <- forall m n. Name -> (OccName -> OccName) -> TcRnIf m n Name
    newImplicitBinder Name
    op_name OccName -> OccName
    mkDefaultMethodOcc
               ; forall (m :: * -> *) a. Monad m => a -> m a
    return (forall a. a -> Maybe a
    Just (Name
    dm_name, forall ty. DefMethSpec ty
    VanillaDM)) }
        mk_dm_info Name
    op_name (Just (GenericDM (SrcSpan
    loc, Type
    dm_ty)))
          = do { Name
    dm_name <- forall m n.
    Name -> (OccName -> OccName) -> SrcSpan -> TcRnIf m n Name
    newImplicitBinderLoc Name
    op_name OccName -> OccName
    mkDefaultMethodOcc SrcSpan
    loc
               ; forall (m :: * -> *) a. Monad m => a -> m a
    return (forall a. a -> Maybe a
    Just (Name
    dm_name, forall ty. ty -> DefMethSpec ty
    GenericDM Type
    dm_ty)) }

    {-
    Note [Class newtypes and equality predicates]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Consider
            class (a ~ F b) => C a b where
              op :: a -> b

    We cannot represent this by a newtype, even though it's not
    existential, because there are two value fields (the equality
    predicate and op. See #2238

    Moreover,
              class (a ~ F b) => C a b where {}
    Here we can't use a newtype either, even though there is only
    one field, because equality predicates are unboxed, and classes
    are boxed.
    -}

    newImplicitBinder :: Name                       -- Base name
                      -> (OccName -> OccName)       -- Occurrence name modifier
                      -> TcRnIf m n Name            -- Implicit name
    -- Called in GHC.Tc.TyCl.Build to allocate the implicit binders of type/class decls
    -- For source type/class decls, this is the first occurrence
    -- For iface ones, GHC.Iface.Load has already allocated a suitable name in the cache
    newImplicitBinder :: forall m n. Name -> (OccName -> OccName) -> TcRnIf m n Name
    newImplicitBinder Name
    base_name OccName -> OccName
    mk_sys_occ
      = forall m n.
    Name -> (OccName -> OccName) -> SrcSpan -> TcRnIf m n Name
    newImplicitBinderLoc Name
    base_name OccName -> OccName
    mk_sys_occ (Name -> SrcSpan
    nameSrcSpan Name
    base_name)

    newImplicitBinderLoc :: Name                       -- Base name
                         -> (OccName -> OccName)       -- Occurrence name modifier
                         -> SrcSpan
                         -> TcRnIf m n Name            -- Implicit name
    -- Just the same, but lets you specify the SrcSpan
    newImplicitBinderLoc :: forall m n.
    Name -> (OccName -> OccName) -> SrcSpan -> TcRnIf m n Name
    newImplicitBinderLoc Name
    base_name OccName -> OccName
    mk_sys_occ SrcSpan
    loc
      | Just Module
    mod <- Name -> Maybe Module
    nameModule_maybe Name
    base_name
      = forall a b. Module -> OccName -> SrcSpan -> TcRnIf a b Name
    newGlobalBinder Module
    mod OccName
    occ SrcSpan
    loc
      | Bool
    otherwise           -- When typechecking a [d| decl bracket |],
                            -- TH generates types, classes etc with Internal names,
                            -- so we follow suit for the implicit binders
      = do  { Unique
    uniq <- forall gbl lcl. TcRnIf gbl lcl Unique
    newUnique
            ; forall (m :: * -> *) a. Monad m => a -> m a
    return (Unique -> OccName -> SrcSpan -> Name
    mkInternalName Unique
    uniq OccName
    occ SrcSpan
    loc) }
      where
        occ :: OccName
    occ = OccName -> OccName
    mk_sys_occ (Name -> OccName
    nameOccName Name
    base_name)

    -- | Make the 'TyConRepName' for this 'TyCon'
    newTyConRepName :: Name -> TcRnIf gbl lcl TyConRepName
    newTyConRepName :: forall gbl lcl. Name -> TcRnIf gbl lcl Name
    newTyConRepName Name
    tc_name
      | Just Module
    mod <- Name -> Maybe Module
    nameModule_maybe Name
    tc_name
      , (Module
    mod, OccName
    occ) <- Module -> OccName -> (Module, OccName)
    tyConRepModOcc Module
    mod (Name -> OccName
    nameOccName Name
    tc_name)
      = forall a b. Module -> OccName -> SrcSpan -> TcRnIf a b Name
    newGlobalBinder Module
    mod OccName
    occ SrcSpan
    noSrcSpan
      | Bool
    otherwise
      = forall m n. Name -> (OccName -> OccName) -> TcRnIf m n Name
    newImplicitBinder Name
    tc_name OccName -> OccName
    mkTyConRepOcc