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

    \section[DataCon]{@DataCon@: Data Constructors}
    -}

    {-# LANGUAGE DeriveDataTypeable #-}
    {-# OPTIONS_GHC -Wno-orphans #-} -- Outputable, Binary

    module GHC.Core.DataCon (
            -- * Main data types
            DataCon, DataConRep(..),
            SrcStrictness(..), SrcUnpackedness(..),
            HsSrcBang(..), HsBang(..), HsImplBang(..),
            StrictnessMark(..),
            ConTag,
            DataConEnv,

            -- ** Equality specs
            EqSpec, mkEqSpec, eqSpecTyVar, eqSpecType,
            eqSpecPair, eqSpecPreds,

            -- ** Field labels
            FieldLabel(..), flLabel, FieldLabelString,

            -- ** Type construction
            mkHsSrcBang, mkDataCon, fIRST_TAG,

            -- ** Type deconstruction
            dataConRepType, dataConInstSig, dataConFullSig,
            dataConName, dataConIdentity, dataConTag, dataConTagZ,
            dataConTyCon, dataConOrigTyCon,
            dataConWrapperType,
            dataConNonlinearType,
            dataConDisplayType,
            dataConUnivTyVars, dataConExTyCoVars, dataConUnivAndExTyCoVars,
            dataConConcreteTyVars,
            dataConUserTyVars, dataConUserTyVarBinders,
            dataConTheta,
            dataConStupidTheta,
            dataConOtherTheta,
            dataConInstArgTys, dataConOrigArgTys, dataConOrigResTy,
            dataConInstOrigArgTys, dataConRepArgTys, dataConResRepTyArgs,
            dataConInstUnivs,
            dataConFieldLabels, dataConFieldType, dataConFieldType_maybe,
            dataConSrcBangs,
            dataConSourceArity, dataConRepArity,
            dataConIsInfix,
            dataConWorkId, dataConWrapId, dataConWrapId_maybe,
            dataConImplicitTyThings,
            dataConRepStrictness, dataConImplBangs, dataConBoxer,

            splitDataProductType_maybe,

            -- ** Predicates on DataCons
            isNullarySrcDataCon, isNullaryRepDataCon,
            isTupleDataCon, isBoxedTupleDataCon, isUnboxedTupleDataCon,
            isUnboxedSumDataCon, isCovertGadtDataCon,
            isVanillaDataCon, isNewDataCon, isTypeDataCon,
            classDataCon, dataConCannotMatch,
            dataConUserTyVarsNeedWrapper, checkDataConTyVars,
            isBanged, isMarkedStrict, cbvFromStrictMark, eqHsBang, isSrcStrict, isSrcUnpacked,
            specialPromotedDc,

            -- ** Promotion related functions
            promoteDataCon
        ) where

    import GHC.Prelude

    import Language.Haskell.Syntax.Basic
    import Language.Haskell.Syntax.Module.Name

    import {-# SOURCE #-} GHC.Types.Id.Make ( DataConBoxer )
    import GHC.Core.Type as Type
    import GHC.Core.Coercion
    import GHC.Core.Unify
    import GHC.Core.TyCon
    import GHC.Core.TyCo.Subst
    import GHC.Core.TyCo.Compare( eqType )
    import GHC.Core.Multiplicity
    import {-# SOURCE #-} GHC.Types.TyThing
    import GHC.Types.FieldLabel
    import GHC.Types.SourceText
    import GHC.Core.Class
    import GHC.Types.Name
    import GHC.Builtin.Names
    import GHC.Core.Predicate
    import GHC.Types.Var
    import GHC.Types.Var.Env
    import GHC.Types.Basic
    import GHC.Data.FastString
    import GHC.Unit.Types
    import GHC.Utils.Binary
    import GHC.Types.Unique.FM ( UniqFM )
    import GHC.Types.Unique.Set
    import GHC.Builtin.Uniques( mkAlphaTyVarUnique )
    import GHC.Data.Graph.UnVar  -- UnVarSet and operations

    import {-# SOURCE #-} GHC.Tc.Utils.TcType ( ConcreteTyVars )

    import GHC.Utils.Outputable
    import GHC.Utils.Misc
    import GHC.Utils.Panic

    import Data.ByteString (ByteString)
    import qualified Data.ByteString.Builder as BSB
    import qualified Data.ByteString.Lazy    as LBS
    import qualified Data.Data as Data
    import Data.Char
    import Data.List( find )

    {-
    Note [Data constructor representation]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Consider the following Haskell data type declaration

            data T = T !Int ![Int]

    Using the strictness annotations, GHC will represent this as

            data T = T Int# [Int]

    That is, the Int has been unboxed.  Furthermore, the Haskell source construction

            T e1 e2

    is translated to

            case e1 of { I# x ->
            case e2 of { r ->
            T x r }}

    That is, the first argument is unboxed, and the second is evaluated.  Finally,
    pattern matching is translated too:

            case e of { T a b -> ... }

    becomes

            case e of { T a' b -> let a = I# a' in ... }

    To keep ourselves sane, we name the different versions of the data constructor
    differently, as follows in Note [Data Constructor Naming].

    The `dcRepType` field of a `DataCon` contains the type of the representation of
    the constructor /worker/, also called the Core representation.

    The Core representation may differ from the type of the constructor /wrapper/
    (built by `mkDataConRep`). Besides unpacking (as seen in the example above),
    dictionaries and coercions become explict arguments in the Core representation
    of a constructor.

    Note that this representation is still *different* from runtime
    representation. (Which is what STG uses after unarise).
    See Note [Constructor applications in STG] in GHC.Stg.Syntax.

    Note [Data Constructor Naming]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Each data constructor C has two, and possibly up to four, Names associated with it:

                       OccName   Name space   Name of   Notes
     ---------------------------------------------------------------------------
     The "data con itself"   C     DataName   DataCon   In dom( GlobalRdrEnv )
     The "worker data con"   C     VarName    Id        The worker
     The "wrapper data con"  $WC   VarName    Id        The wrapper
     The "newtype coercion"  :CoT  TcClsName  TyCon

    EVERY data constructor (incl for newtypes) has the former two (the
    data con itself, and its worker.  But only some data constructors have a
    wrapper (see Note [The need for a wrapper]).

    Each of these three has a distinct Unique.  The "data con itself" name
    appears in the output of the renamer, and names the Haskell-source
    data constructor.  The type checker translates it into either the wrapper Id
    (if it exists) or worker Id (otherwise).

    The data con has one or two Ids associated with it:

    The "worker Id", is the actual data constructor.
    * Every data constructor (newtype or data type) has a worker

    * The worker is very like a primop, in that it has no binding.

    * For a *data* type, the worker *is* the data constructor;
      it has no unfolding

    * For a *newtype*, the worker has a compulsory unfolding which
      does a cast, e.g.
            newtype T = MkT Int
            The worker for MkT has unfolding
                    \\(x:Int). x `cast` sym CoT
      Here CoT is the type constructor, witnessing the FC axiom
            axiom CoT : T = Int

    The "wrapper Id", \$WC, goes as follows

    * Its type is exactly what it looks like in the source program.

    * It is an ordinary function, and it gets a top-level binding
      like any other function.

    * The wrapper Id isn't generated for a data type if there is
      nothing for the wrapper to do.  That is, if its defn would be
            \$wC = C

    Note [Data constructor workers and wrappers]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    * Algebraic data types
      - Always have a worker, with no unfolding
      - May or may not have a wrapper; see Note [The need for a wrapper]

    * Newtypes
      - Always have a worker, which has a compulsory unfolding (just a cast)
      - May or may not have a wrapper; see Note [The need for a wrapper]

    * INVARIANT: the dictionary constructor for a class
                 never has a wrapper.

    * See Note [Data Constructor Naming] for how the worker and wrapper
      are named

    * The workers don't take the dcStupidTheta dicts as arguments, while the
      wrappers currently do

    * The wrapper (if it exists) takes dcOrigArgTys as its arguments.
      The worker takes dataConRepArgTys as its arguments
      If the wrapper is absent, dataConRepArgTys is the same as dcOrigArgTys

    * The 'NoDataConRep' case of DataConRep is important. Not only is it
      efficient, but it also ensures that the wrapper is replaced by the
      worker (because it *is* the worker) even when there are no
      args. E.g. in
                   f (:) x
      the (:) *is* the worker.  This is really important in rule matching,
      (We could match on the wrappers, but that makes it less likely that
      rules will match when we bring bits of unfoldings together.)

    Note [The need for a wrapper]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Why might the wrapper have anything to do?  The full story is
    in wrapper_reqd in GHC.Types.Id.Make.mkDataConRep.

    * Unboxing strict fields (with -funbox-strict-fields)
            data T = MkT !(Int,Int)
            \$wMkT :: (Int,Int) -> T
            \$wMkT (x,y) = MkT x y
      Notice that the worker has two fields where the wrapper has
      just one.  That is, the worker has type
                    MkT :: Int -> Int -> T

    * Equality constraints for GADTs
            data T a where { MkT :: a -> T [a] }

      The worker gets a type with explicit equality
      constraints, thus:
            MkT :: forall a b. (a=[b]) => b -> T a

      The wrapper has the programmer-specified type:
            \$wMkT :: a -> T [a]
            \$wMkT a x = MkT [a] a [a] x
      The third argument is a coercion
            [a] :: [a]~[a]

    * Data family instances may do a cast on the result

    * Type variables may be permuted; see MkId
      Note [Data con wrappers and GADT syntax]

    * Datatype contexts require dropping some dictionary arguments.
      See Note [Instantiating stupid theta].

    Note [The stupid context]
    ~~~~~~~~~~~~~~~~~~~~~~~~~
    Data types can have a context:

            data (Eq a, Ord b) => T a b = T1 a b | T2 a

    And that makes the constructors have a context too. A constructor's context
    isn't necessarily the same as the data type's context, however. Per the
    Haskell98 Report, the part of the datatype context that is used in a data
    constructor is the largest subset of the datatype context that constrains
    only the type variables free in the data constructor's field types. For
    example, here are the types of T1 and T2:

            T1 :: (Eq a, Ord b) => a -> b -> T a b
            T2 :: (Eq a) => a -> T a b

    Notice that T2's context is "thinned". Since its field is of type `a`, only
    the part of the datatype context that mentions `a`—that is, `Eq a`—is
    included in T2's context. On the other hand, T1's fields mention both `a`
    and `b`, so T1's context includes all of the datatype context.

    Furthermore, this context pops up when pattern matching
    (though GHC hasn't implemented this, but it is in H98, and
    I've fixed GHC so that it now does):

            f (T2 x) = x
    gets inferred type
            f :: Eq a => T a b -> a

    I say the context is "stupid" because the dictionaries passed
    are immediately discarded -- they do nothing and have no benefit.
    (See Note [Instantiating stupid theta].)
    It's a flaw in the language.

    GHC has made some efforts to correct this flaw. In GHC, datatype contexts
    are not available by default. Instead, one must explicitly opt in to them by
    using the DatatypeContexts extension. To discourage their use, GHC has
    deprecated DatatypeContexts.

    Some other notes about stupid contexts:

    * Stupid contexts can interact badly with `deriving`. For instance, it's
      unclear how to make this derived Functor instance typecheck:

        data Eq a => T a = MkT a
          deriving Functor

      This is because the derived instance would need to look something like
      `instance Functor T where ...`, but there is nowhere to mention the
      requisite `Eq a` constraint. For this reason, GHC will throw an error if a
      user attempts to derive an instance for Functor (or a Functor-like class)
      where the last type variable is used in a datatype context. For Generic(1),
      the requirements are even harsher, as stupid contexts are not allowed at all
      in derived Generic(1) instances. (We could consider relaxing this requirement
      somewhat, although no one has asked for this yet.)

      Stupid contexts are permitted when deriving instances of non-Functor-like
      classes, or when deriving instances of Functor-like classes where the last
      type variable isn't mentioned in the stupid context. For example, the
      following is permitted:

        data Show a => T a = MkT deriving Eq

      Note that because of the "thinning" behavior mentioned above, the generated
      Eq instance should not mention `Show a`, as the type of MkT doesn't require
      it. That is, the following should be generated (#20501):

        instance Eq (T a) where
          (MkT == MkT) = True

    * It's not obvious how stupid contexts should interact with GADTs. For this
      reason, GHC disallows combining datatype contexts with GADT syntax. As a
      result, dcStupidTheta is always empty for data types defined using GADT
      syntax.

    Note [Instantiating stupid theta]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Consider a data type with a "stupid theta" (see
    Note [The stupid context]):

      data Ord a => T a = MkT (Maybe a)

    We want to generate an Ord constraint for every use of MkT; but
    we also want to allow visible type application, such as

       MkT @Int

    To achieve this, the wrapper for a data (or newtype) constructor
    with a datatype context contains a lambda which drops the dictionary
    argments corresponding to the datatype context:

       /\a \(_d:Ord a). MkT @a

    Notice that the wrapper discards the dictionary argument d.
    We don't need it; it was only there to generate a Wanted constraint.
    (That is why it is stupid.)

    This all happens in GHC.Types.Id.Make.mkDataConRep.

    ************************************************************************
    *                                                                      *
    \subsection{Data constructors}
    *                                                                      *
    ************************************************************************
    -}

    -- | A data constructor
    data DataCon
      = MkData {
            DataCon -> Name
    dcName    :: Name,      -- This is the name of the *source data con*
                                    -- (see "Note [Data Constructor Naming]" above)
            DataCon -> Unique
    dcUnique :: Unique,     -- Cached from Name
            DataCon -> Arity
    dcTag    :: ConTag,     -- ^ Tag, used for ordering 'DataCon's

            -- Running example:
            --
            --      *** As declared by the user
            --  data T a b c where
            --    MkT :: forall c y x b. (x~y,Ord x) => x -> y -> T (x,y) b c

            --      *** As represented internally
            --  data T a b c where
            --    MkT :: forall a b c. forall x y. (a~(x,y),x~y,Ord x)
            --        => x -> y -> T a b c
            --
            -- The next six fields express the type of the constructor, in pieces
            -- e.g.
            --
            --      dcUnivTyVars       = [a,b,c]
            --      dcExTyCoVars       = [x,y]
            --      dcUserTyVarBinders = [c,y,x,b]
            --      dcEqSpec           = [a~(x,y)]
            --      dcOtherTheta       = [x~y, Ord x]
            --      dcOrigArgTys       = [x,y]
            --      dcRepTyCon         = T

            -- In general, the dcUnivTyVars are NOT NECESSARILY THE SAME AS THE
            -- TYVARS FOR THE PARENT TyCon. (This is a change (Oct05): previously,
            -- vanilla datacons guaranteed to have the same type variables as their
            -- parent TyCon, but that seems ugly.) They can be different in the case
            -- where a GADT constructor uses different names for the universal
            -- tyvars than does the tycon. For example:
            --
            --   data H a where
            --     MkH :: b -> H b
            --
            -- Here, the tyConTyVars of H will be [a], but the dcUnivTyVars of MkH
            -- will be [b].

            DataCon -> Bool
    dcVanilla :: Bool,      -- True <=> This is a vanilla Haskell 98 data constructor
                                    --          Its type is of form
                                    --              forall a1..an . t1 -> ... tm -> T a1..an
                                    --          No existentials, no coercions, nothing.
                                    -- That is: dcExTyCoVars = dcEqSpec = dcOtherTheta = []
                    -- NB 1: newtypes always have a vanilla data con
                    -- NB 2: a vanilla constructor can still be declared in GADT-style
                    --       syntax, provided its type looks like the above.
                    --       The declaration format is held in the TyCon (algTcGadtSyntax)

            -- dcUnivTyVars: Universally-quantified type vars [a,b,c]
            -- INVARIANT: length matches arity of the dcRepTyCon
            -- INVARIANT: result type of data con worker is exactly (T a b c)
            -- COROLLARY: The dcUnivTyVars are always in one-to-one correspondence with
            --            the tyConTyVars of the parent TyCon
            DataCon -> [TyVar]
    dcUnivTyVars     :: [TyVar],

            -- Existentially-quantified type and coercion vars [x,y]
            -- For an example involving coercion variables,
            -- Why TyCoVars? See Note [Existential coercion variables]
            DataCon -> [TyVar]
    dcExTyCoVars     :: [TyCoVar],

            -- INVARIANT: the UnivTyVars and ExTyCoVars all have distinct OccNames
            -- Reason: less confusing, and easier to generate Iface syntax

            -- The type variables of this data constructor that must be
            -- instantiated to concrete types. For example: the RuntimeRep
            -- variables of unboxed tuples and unboxed sums.
            --
            -- See Note [Representation-polymorphism checking built-ins]
            -- in GHC.Tc.Utils.Concrete.
            DataCon -> ConcreteTyVars
    dcConcreteTyVars :: ConcreteTyVars,

            -- The type/coercion vars in the order the user wrote them [c,y,x,b]
            -- INVARIANT(dataConTyVars): the set of tyvars in dcUserTyVarBinders is
            --    exactly the set of tyvars (*not* covars) of dcExTyCoVars unioned
            --    with the set of dcUnivTyVars whose tyvars do not appear in dcEqSpec
            -- So dcUserTyVarBinders is a subset of (dcUnivTyVars ++ dcExTyCoVars)
            -- See Note [DataCon user type variable binders]
            DataCon -> [InvisTVBinder]
    dcUserTyVarBinders :: [InvisTVBinder],

            DataCon -> [EqSpec]
    dcEqSpec :: [EqSpec],   -- Equalities derived from the result type,
                                    -- _as written by the programmer_.
                                    -- Only non-dependent GADT equalities (dependent
                                    -- GADT equalities are in the covars of
                                    -- dcExTyCoVars).

                    -- This field allows us to move conveniently between the two ways
                    -- of representing a GADT constructor's type:
                    --      MkT :: forall a b. (a ~ [b]) => b -> T a
                    --      MkT :: forall b. b -> T [b]
                    -- Each equality is of the form (a ~ ty), where 'a' is one of
                    -- the universally quantified type variables. Moreover, the
                    -- only place in the DataCon where this 'a' will occur is in
                    -- dcUnivTyVars. See [The dcEqSpec domain invariant].

                    -- The next two fields give the type context of the data constructor
                    --      (aside from the GADT constraints,
                    --       which are given by the dcExpSpec)
                    -- In GADT form, this is *exactly* what the programmer writes, even if
                    -- the context constrains only universally quantified variables
                    --      MkT :: forall a b. (a ~ b, Ord b) => a -> T a b
            DataCon -> [Type]
    dcOtherTheta :: ThetaType,  -- The other constraints in the data con's type
                                        -- other than those in the dcEqSpec

            DataCon -> [Type]
    dcStupidTheta :: ThetaType,     -- The context of the data type declaration
                                            --      data Eq a => T a = ...
                                            -- or, rather, a "thinned" version thereof
                    -- "Thinned", because the Report says
                    -- to eliminate any constraints that don't mention
                    -- tyvars free in the arg types for this constructor.
                    -- See Note [The stupid context].
                    --
                    -- INVARIANT: the free tyvars of dcStupidTheta are a subset of dcUnivTyVars
                    -- Reason: dcStupidTeta is gotten by thinning the stupid theta from the tycon
                    --
                    -- "Stupid", because the dictionaries aren't used for anything.
                    -- Indeed, [as of March 02] they are no longer in the type of
                    -- the wrapper Id, because that makes it harder to use the wrap-id
                    -- to rebuild values after record selection or in generics.

            DataCon -> [Scaled Type]
    dcOrigArgTys :: [Scaled Type],  -- Original argument types
                                            -- (before unboxing and flattening of strict fields)
            DataCon -> Type
    dcOrigResTy :: Type,            -- Original result type, as seen by the user
                    -- NB: for a data instance, the original user result type may
                    -- differ from the DataCon's representation TyCon.  Example
                    --      data instance T [a] where MkT :: a -> T [a]
                    -- The dcOrigResTy is T [a], but the dcRepTyCon might be R:TList

            -- Now the strictness annotations and field labels of the constructor
            DataCon -> [HsSrcBang]
    dcSrcBangs :: [HsSrcBang],
                    -- See Note [Bangs on data constructor arguments]
                    --
                    -- The [HsSrcBang] as written by the programmer.
                    --
                    -- Matches 1-1 with dcOrigArgTys
                    -- Hence length = dataConSourceArity dataCon

            DataCon -> [FieldLabel]
    dcFields  :: [FieldLabel],
                    -- Field labels for this constructor, in the
                    -- same order as the dcOrigArgTys;
                    -- length = 0 (if not a record) or dataConSourceArity.

            -- The curried worker function that corresponds to the constructor:
            -- It doesn't have an unfolding; the code generator saturates these Ids
            -- and allocates a real constructor when it finds one.
            DataCon -> TyVar
    dcWorkId :: Id,

            -- Constructor representation
            DataCon -> DataConRep
    dcRep      :: DataConRep,

            -- Cached; see Note [DataCon arities]
            -- INVARIANT: dcRepArity    == length dataConRepArgTys + count isCoVar (dcExTyCoVars)
            -- INVARIANT: dcSourceArity == length dcOrigArgTys
            DataCon -> Arity
    dcRepArity    :: Arity,
            DataCon -> Arity
    dcSourceArity :: Arity,

            -- Result type of constructor is T t1..tn
            DataCon -> TyCon
    dcRepTyCon  :: TyCon,           -- Result tycon, T

            DataCon -> Type
    dcRepType   :: Type,    -- Type of the constructor
                                    --      forall a x y. (a~(x,y), x~y, Ord x) =>
                                    --        x -> y -> T a
                                    -- (this is *not* of the constructor wrapper Id:
                                    --  see Note [Data constructor representation])
            -- Notice that the existential type parameters come *second*.
            -- Reason: in a case expression we may find:
            --      case (e :: T t) of
            --        MkT x y co1 co2 (d:Ord x) (v:r) (w:F s) -> ...
            -- It's convenient to apply the rep-type of MkT to 't', to get
            --      forall x y. (t~(x,y), x~y, Ord x) => x -> y -> T t
            -- and use that to check the pattern.  Mind you, this is really only
            -- used in GHC.Core.Lint.

            DataCon -> Bool
    dcInfix :: Bool,        -- True <=> declared infix
                                    -- Used for Template Haskell and 'deriving' only
                                    -- The actual fixity is stored elsewhere

            DataCon -> TyCon
    dcPromoted :: TyCon    -- The promoted TyCon
                                   -- See Note [Promoted data constructors] in GHC.Core.TyCon
      }

    {- Note [TyVarBinders in DataCons]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    For the TyVarBinders in a DataCon and PatSyn,
    each argument flag is either Inferred or Specified, never Required.
    Lifting this restriction is tracked at #18389 (DataCon) and #23704 (PatSyn).

    Why do we need the TyVarBinders, rather than just the TyVars?  So that
    we can construct the right type for the DataCon with its foralls
    attributed the correct visibility.  That in turn governs whether you
    can use visible type application at a call of the data constructor.

    See also [DataCon user type variable binders] for an extended discussion on the
    order in which TyVarBinders appear in a DataCon.

    Note [Existential coercion variables]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    For now (Aug 2018) we can't write coercion quantifications in source Haskell, but
    we can in Core. Consider having:

      data T :: forall k. k -> k -> Constraint where
        MkT :: forall k (a::k) (b::k).
               forall k' (c::k') (co::k'~k).
               (b ~# (c|>co)) => T k a b

      dcUnivTyVars       = [k,a,b]
      dcExTyCoVars       = [k',c,co]
      dcUserTyVarBinders = [k,a,k',c]
      dcEqSpec           = [b ~# (c|>co)]
      dcOtherTheta       = []
      dcOrigArgTys       = []
      dcRepTyCon         = T

    Function call 'dataConKindEqSpec' returns [k'~k]

    Note [DataCon arities]
    ~~~~~~~~~~~~~~~~~~~~~~
    A `DataCon`'s source and core representation may differ, meaning the source
    arity (`dcSourceArity`) and the core representation arity (`dcRepArity`) may
    differ too.

    Note that the source arity isn't exactly the number of arguments the data con
    /wrapper/ has, since `dcSourceArity` doesn't count constraints -- which may
    appear in the wrapper through `DatatypeContexts`, or if the constructor stores a
    dictionary. In this sense, the source arity counts the number of non-constraint
    arguments that appear at the source level.
      On the other hand, the Core representation arity is the number of arguments
    of the data constructor in its Core representation, which is also the number
    of arguments of the data con /worker/.

    The arity might differ since `dcRepArity` takes into account arguments such as
    quantified dictionaries and coercion arguments, lifted and unlifted (despite
    the unlifted coercion arguments having a zero-width runtime representation).
    For example:
       MkT :: Ord a => a -> T a
        dcSourceArity = 1
        dcRepArity    = 2

       MkU :: (b ~ '[]) => U b
        dcSourceArity = 0
        dcRepArity    = 1

    The arity might also differ due to unpacking, for example, consider the
    following datatype and its wrapper and worker's type:
       data V = MkV !() !Int
       $WMkV :: () -> Int -> V
         MkV :: Int# -> V
    As you see, because of unpacking we have both dropped the unit argument and
    unboxed the Int. In this case, the source arity (which is the arity of the
    wrapper) is 2, while the Core representation arity (the arity of the worker) is 1.

    Note [DataCon user type variable binders]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    A DataCon has two different sets of type variables:

    * dcUserTyVarBinders, for the type variables binders in the order in which they
      originally arose in the user-written type signature.

      - They are the forall'd binders of the data con /wrapper/, which the user calls.

      - Their order *does* matter for TypeApplications, so they are full TyVarBinders,
        complete with visibilities.

    * dcUnivTyVars and dcExTyCoVars, for the "true underlying" (i.e. of the data
      con worker) universal type variable and existential type/coercion variables,
      respectively.

      - They (i.e. univ ++ ex) are the forall'd variables of the data con /worker/

      - Their order is irrelevant for the purposes of TypeApplications,
        and as a consequence, they do not come equipped with visibilities
        (that is, they are TyVars/TyCoVars instead of ForAllTyBinders).

    Often (dcUnivTyVars ++ dcExTyCoVars) = dcUserTyVarBinders; but they may differ
    for two reasons, coming next:

    --- Reason (R1): Order of quantification in GADT syntax ---

    In System FC, data constructor type signatures always quantify over all of
    their universal type variables, followed by their existential type variables.
    Normally, this isn't a problem, as most datatypes naturally quantify their type
    variables in this order anyway. For example:

      data T a b = forall c. MkT b c

    Here, we have `MkT :: forall {k} (a :: k) (b :: *) (c :: *). b -> c -> T a b`,
    where k, a, and b are universal and c is existential. (The inferred variable k
    isn't available for TypeApplications, hence why it's in braces.) This is a
    perfectly reasonable order to use, as the syntax of H98-style datatypes
    (+ ExistentialQuantification) suggests it.

    Things become more complicated when GADT syntax enters the picture. Consider
    this example:

      data X a where
        MkX :: forall b a. b -> Proxy a -> X a

    If we adopt the earlier approach of quantifying all the universal variables
    followed by all the existential ones, GHC would come up with this type
    signature for MkX:

      MkX :: forall {k} (a :: k) (b :: *). b -> Proxy a -> X a

    But this is not what we want at all! After all, if a user were to use
    TypeApplications on MkX, they would expect to instantiate `b` before `a`,
    as that's the order in which they were written in the `forall`. (See #11721.)
    Instead, we'd like GHC to come up with this type signature:

      MkX :: forall {k} (b :: *) (a :: k). b -> Proxy a -> X a

    In fact, even if we left off the explicit forall:

      data X a where
        MkX :: b -> Proxy a -> X a

    Then a user should still expect `b` to be quantified before `a`, since
    according to the rules of TypeApplications, in the absence of `forall` GHC
    performs a stable topological sort on the type variables in the user-written
    type signature, which would place `b` before `a`.

    --- Reason (R2): GADT constructors quantify over different variables ---

    GADT constructors may quantify over different variables than the worker
    would.  Consider
       data T a b where
          MkT :: forall c d. c -> T [c] d

    The dcUserTyVarBinders must be [c, d] -- that's what the user quantified over.
    But c is actually existential, as it is not equal to either of the two
    universal variables.

    Here is what we'll get:

      dcUserTyVarBinders = [c, d]
      dcUnivTyVars = [a, d]
      dcExTyCoVars = [c]

    Note that dcUnivTyVars contains `a` from the type header (the `data T a b`)
    and `d` from the signature for MkT. This is done because d is used in place
    of b in the result of MkT, and so we use the name d for the universal, as that
    might improve error messages. On the other hand, we need to use a fresh name
    for the first universal (recalling that the result of a worker must be the
    type constructor applied to a sequence of plain variables), so we use `a`, from
    the header. This choice of universals is made in GHC.Tc.TyCl.mkGADTVars.

    Because c is not a universal, it is an existential. Here, we see that (even
    ignoring order) dcUserTyVarBinders is not dcUnivTyVars ⋃ dcExTyCoVars, because
    the latter has `a` while the former does not. To understand this better, let's
    look at this type for the "true underlying" worker data con:

          MkT :: forall a d. forall c. (a ~# [c]) => c -> T a d

    We see here that the `a` universal is connected with the `c` existential via
    an equality constraint. It will always be the case (see the code in mkGADTVars)
    that the universals not mentioned in dcUserTyVarBinders will be used in a
    GADT equality -- that is, used on the left-hand side of an element of dcEqSpec:

      dcEqSpec = [a ~# [c]]

    Putting this all together, all variables used on the left-hand side of an
    equation in the dcEqSpec will be in dcUnivTyVars but *not* in
    dcUserTyVarBinders.

    --- End of Reasons ---

    INVARIANT(dataConTyVars): the set of tyvars in dcUserTyVarBinders
    consists of:

    * The set of tyvars in dcUnivTyVars whose type variables do not appear in
      dcEqSpec, unioned with:

    * The set of tyvars (*not* covars) in dcExTyCoVars
      No covars here because because they're not user-written

    When comparing for equality, we ignore differences concerning type variables
    whose kinds have kind Constraint.

    The word "set" is used above because the order in which the tyvars appear in
    dcUserTyVarBinders can be completely different from the order in dcUnivTyVars or
    dcExTyCoVars. That is, the tyvars in dcUserTyVarBinders are a permutation of
    (tyvars of dcExTyCoVars + a subset of dcUnivTyVars). But aside from the
    ordering, they in fact share the same type variables (with the same Uniques). We
    sometimes refer to this as "the dcUserTyVarBinders invariant". It is checked
    in checkDataConTyVars.

    dcUserTyVarBinders, as the name suggests, is the one that users will
    see most of the time. It's used when computing the type signature of a
    data constructor wrapper (see dataConWrapperType), and as a result,
    it's what matters from a TypeApplications perspective.

    Note [The dcEqSpec domain invariant]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Consider this example of a GADT constructor:

      data Y a where
        MkY :: Bool -> Y Bool

    The user-written type of MkY is `Bool -> Y Bool`, but what is the underlying
    Core type for MkY? There are two conceivable possibilities:

    1. MkY :: forall a. (a ~# Bool) => Bool -> Y a
    2. MkY :: forall a. (a ~# Bool) => a    -> Y a

    In practice, GHC picks (1) as the Core type for MkY. This is because we
    maintain an invariant that the type variables in the domain of dcEqSpec will
    only ever appear in the dcUnivTyVars. As a consequence, the type variables in
    the domain of dcEqSpec will /never/ appear in the dcExTyCoVars, dcOtherTheta,
    dcOrigArgTys, or dcOrigResTy; these can only ever mention variables from
    dcUserTyVarBinders, which excludes things in the domain of dcEqSpec.
    (See Note [DataCon user type variable binders].) This explains why GHC would
    not pick (2) as the Core type, since the argument type `a` mentions a type
    variable in the dcEqSpec.

    There are certain parts of the codebase where it is convenient to apply the
    substitution arising from the dcEqSpec to the dcUnivTyVars in order to obtain
    the user-written return type of a GADT constructor. A consequence of the
    dcEqSpec domain invariant is that you /never/ need to apply the substitution
    to any other part of the constructor type, as they don't require it.
    -}

    -- | Data Constructor Representation
    -- See Note [Data constructor workers and wrappers]
    data DataConRep
      = -- NoDataConRep means that the data con has no wrapper
        NoDataConRep

        -- DCR means that the data con has a wrapper
      | DCR { DataConRep -> TyVar
    dcr_wrap_id :: Id   -- Takes src args, unboxes/flattens,
                                  -- and constructs the representation

            , DataConRep -> DataConBoxer
    dcr_boxer   :: DataConBoxer

            , DataConRep -> [Scaled Type]
    dcr_arg_tys :: [Scaled Type]    -- Final, representation argument types,
                                              -- after unboxing and flattening,
                                              -- and *including* all evidence args

            , DataConRep -> [StrictnessMark]
    dcr_stricts :: [StrictnessMark]  -- 1-1 with dcr_arg_tys
                    -- See also Note [Data-con worker strictness]

            , DataConRep -> [HsImplBang]
    dcr_bangs :: [HsImplBang]  -- The actual decisions made (including failures)
                                         -- about the original arguments; 1-1 with orig_arg_tys
                                         -- See Note [Bangs on data constructor arguments]

        }

    type DataConEnv a = UniqFM DataCon a     -- Keyed by DataCon

    -------------------------

    -- | Haskell Source Bang
    --
    -- Bangs on data constructor arguments as written by the user, including the
    -- source code for exact-printing.
    --
    -- In the AST, the SourceText is deconstructed and hidden inside
    -- 'Language.Haskell.Syntax.Extension.XBangTy' extension point.
    data HsSrcBang
      = HsSrcBang SourceText HsBang -- See Note [Pragma source text] in "GHC.Types.SourceText"

    -- | Make a 'HsSrcBang' from all parts
    mkHsSrcBang :: SourceText -> SrcUnpackedness -> SrcStrictness -> HsSrcBang
    mkHsSrcBang :: SourceText -> SrcUnpackedness -> SrcStrictness -> HsSrcBang
    mkHsSrcBang SourceText
    stext SrcUnpackedness
    u SrcStrictness
    s = SourceText -> HsBang -> HsSrcBang
    HsSrcBang SourceText
    stext (SrcUnpackedness -> SrcStrictness -> HsBang
    HsBang SrcUnpackedness
    u SrcStrictness
    s)

    -- | Haskell Implementation Bang
    --
    -- Bangs of data constructor arguments as generated by the compiler
    -- after consulting HsSrcBang, flags, etc.
    data HsImplBang
      = HsLazy    -- ^ Lazy field, or one with an unlifted type
      | HsStrict Bool -- ^ Strict but not unpacked field
                      -- True <=> we could have unpacked, but opted not to
                      -- because of -O0.
                      -- See Note [Detecting useless UNPACK pragmas]
      | HsUnpack (Maybe Coercion)
        -- ^ Strict and unpacked field
        -- co :: arg-ty ~ product-ty HsBang
      deriving Typeable HsImplBang
    Typeable HsImplBang =>
    (forall (c :: * -> *).
     (forall d b. Data d => c (d -> b) -> d -> c b)
     -> (forall g. g -> c g) -> HsImplBang -> c HsImplBang)
    -> (forall (c :: * -> *).
        (forall b r. Data b => c (b -> r) -> c r)
        -> (forall r. r -> c r) -> Constr -> c HsImplBang)
    -> (HsImplBang -> Constr)
    -> (HsImplBang -> DataType)
    -> (forall (t :: * -> *) (c :: * -> *).
        Typeable t =>
        (forall d. Data d => c (t d)) -> Maybe (c HsImplBang))
    -> (forall (t :: * -> * -> *) (c :: * -> *).
        Typeable t =>
        (forall d e. (Data d, Data e) => c (t d e))
        -> Maybe (c HsImplBang))
    -> ((forall b. Data b => b -> b) -> HsImplBang -> HsImplBang)
    -> (forall r r'.
        (r -> r' -> r)
        -> r -> (forall d. Data d => d -> r') -> HsImplBang -> r)
    -> (forall r r'.
        (r' -> r -> r)
        -> r -> (forall d. Data d => d -> r') -> HsImplBang -> r)
    -> (forall u. (forall d. Data d => d -> u) -> HsImplBang -> [u])
    -> (forall u.
        Arity -> (forall d. Data d => d -> u) -> HsImplBang -> u)
    -> (forall (m :: * -> *).
        Monad m =>
        (forall d. Data d => d -> m d) -> HsImplBang -> m HsImplBang)
    -> (forall (m :: * -> *).
        MonadPlus m =>
        (forall d. Data d => d -> m d) -> HsImplBang -> m HsImplBang)
    -> (forall (m :: * -> *).
        MonadPlus m =>
        (forall d. Data d => d -> m d) -> HsImplBang -> m HsImplBang)
    -> Data HsImplBang
    HsImplBang -> Constr
    HsImplBang -> DataType
    (forall b. Data b => b -> b) -> HsImplBang -> HsImplBang
    forall a.
    Typeable a =>
    (forall (c :: * -> *).
     (forall d b. Data d => c (d -> b) -> d -> c b)
     -> (forall g. g -> c g) -> a -> c a)
    -> (forall (c :: * -> *).
        (forall b r. Data b => c (b -> r) -> c r)
        -> (forall r. r -> c r) -> Constr -> c a)
    -> (a -> Constr)
    -> (a -> DataType)
    -> (forall (t :: * -> *) (c :: * -> *).
        Typeable t =>
        (forall d. Data d => c (t d)) -> Maybe (c a))
    -> (forall (t :: * -> * -> *) (c :: * -> *).
        Typeable t =>
        (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c a))
    -> ((forall b. Data b => b -> b) -> a -> a)
    -> (forall r r'.
        (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> a -> r)
    -> (forall r r'.
        (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> a -> r)
    -> (forall u. (forall d. Data d => d -> u) -> a -> [u])
    -> (forall u. Arity -> (forall d. Data d => d -> u) -> a -> u)
    -> (forall (m :: * -> *).
        Monad m =>
        (forall d. Data d => d -> m d) -> a -> m a)
    -> (forall (m :: * -> *).
        MonadPlus m =>
        (forall d. Data d => d -> m d) -> a -> m a)
    -> (forall (m :: * -> *).
        MonadPlus m =>
        (forall d. Data d => d -> m d) -> a -> m a)
    -> Data a
    forall u. Arity -> (forall d. Data d => d -> u) -> HsImplBang -> u
    forall u. (forall d. Data d => d -> u) -> HsImplBang -> [u]
    forall r r'.
    (r -> r' -> r)
    -> r -> (forall d. Data d => d -> r') -> HsImplBang -> r
    forall r r'.
    (r' -> r -> r)
    -> r -> (forall d. Data d => d -> r') -> HsImplBang -> r
    forall (m :: * -> *).
    Monad m =>
    (forall d. Data d => d -> m d) -> HsImplBang -> m HsImplBang
    forall (m :: * -> *).
    MonadPlus m =>
    (forall d. Data d => d -> m d) -> HsImplBang -> m HsImplBang
    forall (c :: * -> *).
    (forall b r. Data b => c (b -> r) -> c r)
    -> (forall r. r -> c r) -> Constr -> c HsImplBang
    forall (c :: * -> *).
    (forall d b. Data d => c (d -> b) -> d -> c b)
    -> (forall g. g -> c g) -> HsImplBang -> c HsImplBang
    forall (t :: * -> *) (c :: * -> *).
    Typeable t =>
    (forall d. Data d => c (t d)) -> Maybe (c HsImplBang)
    forall (t :: * -> * -> *) (c :: * -> *).
    Typeable t =>
    (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c HsImplBang)
    $cgfoldl :: forall (c :: * -> *).
    (forall d b. Data d => c (d -> b) -> d -> c b)
    -> (forall g. g -> c g) -> HsImplBang -> c HsImplBang
    gfoldl :: forall (c :: * -> *).
    (forall d b. Data d => c (d -> b) -> d -> c b)
    -> (forall g. g -> c g) -> HsImplBang -> c HsImplBang
    $cgunfold :: forall (c :: * -> *).
    (forall b r. Data b => c (b -> r) -> c r)
    -> (forall r. r -> c r) -> Constr -> c HsImplBang
    gunfold :: forall (c :: * -> *).
    (forall b r. Data b => c (b -> r) -> c r)
    -> (forall r. r -> c r) -> Constr -> c HsImplBang
    $ctoConstr :: HsImplBang -> Constr
    toConstr :: HsImplBang -> Constr
    $cdataTypeOf :: HsImplBang -> DataType
    dataTypeOf :: HsImplBang -> DataType
    $cdataCast1 :: forall (t :: * -> *) (c :: * -> *).
    Typeable t =>
    (forall d. Data d => c (t d)) -> Maybe (c HsImplBang)
    dataCast1 :: forall (t :: * -> *) (c :: * -> *).
    Typeable t =>
    (forall d. Data d => c (t d)) -> Maybe (c HsImplBang)
    $cdataCast2 :: forall (t :: * -> * -> *) (c :: * -> *).
    Typeable t =>
    (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c HsImplBang)
    dataCast2 :: forall (t :: * -> * -> *) (c :: * -> *).
    Typeable t =>
    (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c HsImplBang)
    $cgmapT :: (forall b. Data b => b -> b) -> HsImplBang -> HsImplBang
    gmapT :: (forall b. Data b => b -> b) -> HsImplBang -> HsImplBang
    $cgmapQl :: forall r r'.
    (r -> r' -> r)
    -> r -> (forall d. Data d => d -> r') -> HsImplBang -> r
    gmapQl :: forall r r'.
    (r -> r' -> r)
    -> r -> (forall d. Data d => d -> r') -> HsImplBang -> r
    $cgmapQr :: forall r r'.
    (r' -> r -> r)
    -> r -> (forall d. Data d => d -> r') -> HsImplBang -> r
    gmapQr :: forall r r'.
    (r' -> r -> r)
    -> r -> (forall d. Data d => d -> r') -> HsImplBang -> r
    $cgmapQ :: forall u. (forall d. Data d => d -> u) -> HsImplBang -> [u]
    gmapQ :: forall u. (forall d. Data d => d -> u) -> HsImplBang -> [u]
    $cgmapQi :: forall u. Arity -> (forall d. Data d => d -> u) -> HsImplBang -> u
    gmapQi :: forall u. Arity -> (forall d. Data d => d -> u) -> HsImplBang -> u
    $cgmapM :: forall (m :: * -> *).
    Monad m =>
    (forall d. Data d => d -> m d) -> HsImplBang -> m HsImplBang
    gmapM :: forall (m :: * -> *).
    Monad m =>
    (forall d. Data d => d -> m d) -> HsImplBang -> m HsImplBang
    $cgmapMp :: forall (m :: * -> *).
    MonadPlus m =>
    (forall d. Data d => d -> m d) -> HsImplBang -> m HsImplBang
    gmapMp :: forall (m :: * -> *).
    MonadPlus m =>
    (forall d. Data d => d -> m d) -> HsImplBang -> m HsImplBang
    $cgmapMo :: forall (m :: * -> *).
    MonadPlus m =>
    (forall d. Data d => d -> m d) -> HsImplBang -> m HsImplBang
    gmapMo :: forall (m :: * -> *).
    MonadPlus m =>
    (forall d. Data d => d -> m d) -> HsImplBang -> m HsImplBang
    Data.Data

    -------------------------
    -- StrictnessMark is used to indicate strictness
    -- of the DataCon *worker* fields
    data StrictnessMark = MarkedStrict | NotMarkedStrict
        deriving StrictnessMark -> StrictnessMark -> Bool
    (StrictnessMark -> StrictnessMark -> Bool)
    -> (StrictnessMark -> StrictnessMark -> Bool) -> Eq StrictnessMark
    forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
    $c== :: StrictnessMark -> StrictnessMark -> Bool
    == :: StrictnessMark -> StrictnessMark -> Bool
    $c/= :: StrictnessMark -> StrictnessMark -> Bool
    /= :: StrictnessMark -> StrictnessMark -> Bool
    Eq

    -- | An 'EqSpec' is a tyvar/type pair representing an equality made in
    -- rejigging a GADT constructor
    data EqSpec = EqSpec TyVar Type

    -- | Make a non-dependent 'EqSpec'
    mkEqSpec :: TyVar -> Type -> EqSpec
    mkEqSpec :: TyVar -> Type -> EqSpec
    mkEqSpec TyVar
    tv Type
    ty = TyVar -> Type -> EqSpec
    EqSpec TyVar
    tv Type
    ty

    eqSpecTyVar :: EqSpec -> TyVar
    eqSpecTyVar :: EqSpec -> TyVar
    eqSpecTyVar (EqSpec TyVar
    tv Type
    _) = TyVar
    tv

    eqSpecType :: EqSpec -> Type
    eqSpecType :: EqSpec -> Type
    eqSpecType (EqSpec TyVar
    _ Type
    ty) = Type
    ty

    eqSpecPair :: EqSpec -> (TyVar, Type)
    eqSpecPair :: EqSpec -> (TyVar, Type)
    eqSpecPair (EqSpec TyVar
    tv Type
    ty) = (TyVar
    tv, Type
    ty)

    eqSpecPreds :: [EqSpec] -> ThetaType
    eqSpecPreds :: [EqSpec] -> [Type]
    eqSpecPreds [EqSpec]
    spec = [ Type -> Type -> Type
    mkPrimEqPred (TyVar -> Type
    mkTyVarTy TyVar
    tv) Type
    ty
                       | EqSpec TyVar
    tv Type
    ty <- [EqSpec]
    spec ]

    instance Outputable EqSpec where
      ppr :: EqSpec -> SDoc
    ppr (EqSpec TyVar
    tv Type
    ty) = (TyVar, Type) -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr (TyVar
    tv, Type
    ty)

    {- Note [Data-con worker strictness]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Notice that we do *not* say the worker Id is strict even if the data
    constructor is declared strict
         e.g.    data T = MkT ![Int] Bool
    Even though most often the evals are done by the *wrapper* $WMkT, there are
    situations in which tag inference will re-insert evals around the worker.
    So for all intents and purposes the *worker* MkT is strict, too!

    Unfortunately, if we exposed accurate strictness of DataCon workers, we'd
    see the following transformation:

      f xs = case xs of xs' { __DEFAULT -> ... case MkT xs b of x { __DEFAULT -> [x] } } -- DmdAnal: Strict in xs
      ==> { drop-seq, binder swap on xs' }
      f xs = case MkT xs b of x { __DEFAULT -> [x] } -- DmdAnal: Still strict in xs
      ==> { case-to-let }
      f xs = let x = MkT xs' b in [x] -- DmdAnal: No longer strict in xs!

    I.e., we are ironically losing strictness in `xs` by dropping the eval on `xs`
    and then doing case-to-let. The issue is that `exprIsHNF` currently says that
    every DataCon worker app is a value. The implicit assumption is that surrounding
    evals will have evaluated strict fields like `xs` before! But now that we had
    just dropped the eval on `xs`, that assumption is no longer valid.

    Long story short: By keeping the demand signature lazy, the Simplifier will not
    drop the eval on `xs` and using `exprIsHNF` to decide case-to-let and others
    remains sound.

    Similarly, during demand analysis in dmdTransformDataConSig, we bump up the
    field demand with `C_01`, *not* `C_11`, because the latter exposes too much
    strictness that will drop the eval on `xs` above.

    This issue is discussed at length in
    "Failed idea: no wrappers for strict data constructors" in #21497 and #22475.

    Note [Bangs on data constructor arguments]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Consider
      data T = MkT !Int {-# UNPACK #-} !Int Bool

    When compiling the module, GHC will decide how to represent
    MkT, depending on the optimisation level, and settings of
    flags like -funbox-small-strict-fields.

    Terminology:
      * HsSrcBang:  What the user wrote
                    Constructors: HsSrcBang

      * HsImplBang: What GHC decided
                    Constructors: HsLazy, HsStrict, HsUnpack

    * If T was defined in this module, MkT's dcSrcBangs field
      records the [HsSrcBang] of what the user wrote; in the example
        [ HsSrcBang _ NoSrcUnpack SrcStrict
        , HsSrcBang _ SrcUnpack SrcStrict
        , HsSrcBang _ NoSrcUnpack NoSrcStrictness]

    * However, if T was defined in an imported module, the importing module
      must follow the decisions made in the original module, regardless of
      the flag settings in the importing module.
      Also see Note [Bangs on imported data constructors] in GHC.Types.Id.Make

    * The dcr_bangs field of the dcRep field records the [HsImplBang]
      If T was defined in this module, Without -O the dcr_bangs might be
        [HsStrict _, HsStrict _, HsLazy]
      With -O it might be
        [HsStrict _, HsUnpack _, HsLazy]
      With -funbox-small-strict-fields it might be
        [HsUnpack, HsUnpack _, HsLazy]
      With -XStrictData it might be
        [HsStrict _, HsUnpack _, HsStrict _]

    Note [Detecting useless UNPACK pragmas]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    We want to issue a warning when there's an UNPACK pragma in the source code,
    but we decided not to unpack.
    However, when compiling with -O0, we never unpack, and that'd generate
    spurious warnings.
    Therefore, we remember in HsStrict a boolean flag, whether we _could_
    have unpacked. This flag is set in GHC.Types.Id.Make.dataConSrcToImplBang.
    Then, in GHC.Tc.TyCl.checkValidDataCon (sub-function check_bang),
    if the user wrote an `{-# UNPACK #-}` pragma (i.e. HsSrcBang contains SrcUnpack)
    we consult HsImplBang:

      HsUnpack _     => field unpacked, no warning
                        Example: data T = MkT {-# UNPACK #-} !Int   [with -O]
      HsStrict True  => field not unpacked because -O0, no warning
                        Example: data T = MkT {-# UNPACK #-} !Int   [with -O0]
      HsStrict False => field not unpacked, warning
                        Example: data T = MkT {-# UNPACK #-} !(Int -> Int)
      HsLazy         => field not unpacked, warning
                        This can happen in two scenarios:

                        1) UNPACK without a bang
                        Example: data T = MkT {-# UNPACK #-} Int
                        This will produce a warning about missing ! before UNPACK.

                        2) UNPACK of an unlifted datatype
                        Because of bug #20204, we currently do not unpack type T,
                        and therefore issue a warning:
                        type IntU :: UnliftedType
                        data IntU = IntU Int#
                        data T = Test {-# UNPACK #-} IntU

    The boolean flag is used only for this warning.
    See #11270 for motivation.

    ************************************************************************
    *                                                                      *
    \subsection{Instances}
    *                                                                      *
    ************************************************************************
    -}

    instance Eq DataCon where
        DataCon
    a == :: DataCon -> DataCon -> Bool
    == DataCon
    b = DataCon -> Unique
    forall a. Uniquable a => a -> Unique
    getUnique DataCon
    a Unique -> Unique -> Bool
    forall a. Eq a => a -> a -> Bool
    == DataCon -> Unique
    forall a. Uniquable a => a -> Unique
    getUnique DataCon
    b
        DataCon
    a /= :: DataCon -> DataCon -> Bool
    /= DataCon
    b = DataCon -> Unique
    forall a. Uniquable a => a -> Unique
    getUnique DataCon
    a Unique -> Unique -> Bool
    forall a. Eq a => a -> a -> Bool
    /= DataCon -> Unique
    forall a. Uniquable a => a -> Unique
    getUnique DataCon
    b

    instance Uniquable DataCon where
        getUnique :: DataCon -> Unique
    getUnique = DataCon -> Unique
    dcUnique

    instance NamedThing DataCon where
        getName :: DataCon -> Name
    getName = DataCon -> Name
    dcName

    instance Outputable DataCon where
        ppr :: DataCon -> SDoc
    ppr DataCon
    con = Name -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr (DataCon -> Name
    dataConName DataCon
    con)

    instance OutputableBndr DataCon where
        pprInfixOcc :: DataCon -> SDoc
    pprInfixOcc DataCon
    con = Name -> SDoc
    forall a. (Outputable a, NamedThing a) => a -> SDoc
    pprInfixName (DataCon -> Name
    dataConName DataCon
    con)
        pprPrefixOcc :: DataCon -> SDoc
    pprPrefixOcc DataCon
    con = Name -> SDoc
    forall a. NamedThing a => a -> SDoc
    pprPrefixName (DataCon -> Name
    dataConName DataCon
    con)

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

    instance Outputable HsBang where
        ppr :: HsBang -> SDoc
    ppr (HsBang SrcUnpackedness
    prag SrcStrictness
    mark) = SrcUnpackedness -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr SrcUnpackedness
    prag SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> SrcStrictness -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr SrcStrictness
    mark

    instance Outputable HsImplBang where
        ppr :: HsImplBang -> SDoc
    ppr HsImplBang
    HsLazy                  = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "Lazy"
        ppr (HsUnpack Maybe Coercion
    Nothing)      = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "Unpacked"
        ppr (HsUnpack (Just Coercion
    co))    = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "Unpacked" SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc
    parens (Coercion -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Coercion
    co)
        ppr (HsStrict Bool
    b)            = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "StrictNotUnpacked" SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc
    parens (Bool -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Bool
    b)

    instance Outputable SrcStrictness where
        ppr :: SrcStrictness -> SDoc
    ppr SrcStrictness
    SrcLazy     = Char -> SDoc
    forall doc. IsLine doc => Char -> doc
    char Char
    '~'
        ppr SrcStrictness
    SrcStrict   = Char -> SDoc
    forall doc. IsLine doc => Char -> doc
    char Char
    '!'
        ppr SrcStrictness
    NoSrcStrict = SDoc
    forall doc. IsOutput doc => doc
    empty

    instance Outputable SrcUnpackedness where
        ppr :: SrcUnpackedness -> SDoc
    ppr SrcUnpackedness
    SrcUnpack   = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "{-# UNPACK #-}"
        ppr SrcUnpackedness
    SrcNoUnpack = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "{-# NOUNPACK #-}"
        ppr SrcUnpackedness
    NoSrcUnpack = SDoc
    forall doc. IsOutput doc => doc
    empty

    instance Outputable StrictnessMark where
        ppr :: StrictnessMark -> SDoc
    ppr StrictnessMark
    MarkedStrict    = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "!"
        ppr StrictnessMark
    NotMarkedStrict = SDoc
    forall doc. IsOutput doc => doc
    empty

    instance Binary StrictnessMark where
        put_ :: WriteBinHandle -> StrictnessMark -> IO ()
    put_ WriteBinHandle
    bh StrictnessMark
    NotMarkedStrict = WriteBinHandle -> Word8 -> IO ()
    putByte WriteBinHandle
    bh Word8
    0
        put_ WriteBinHandle
    bh StrictnessMark
    MarkedStrict    = WriteBinHandle -> Word8 -> IO ()
    putByte WriteBinHandle
    bh Word8
    1
        get :: ReadBinHandle -> IO StrictnessMark
    get ReadBinHandle
    bh =
          do h <- ReadBinHandle -> IO Word8
    getByte ReadBinHandle
    bh
             case h of
               Word8
    0 -> StrictnessMark -> IO StrictnessMark
    forall a. a -> IO a
    forall (m :: * -> *) a. Monad m => a -> m a
    return StrictnessMark
    NotMarkedStrict
               Word8
    1 -> StrictnessMark -> IO StrictnessMark
    forall a. a -> IO a
    forall (m :: * -> *) a. Monad m => a -> m a
    return StrictnessMark
    MarkedStrict
               Word8
    _ -> String -> IO StrictnessMark
    forall a. HasCallStack => String -> a
    panic String
    "Invalid binary format"

    instance Binary SrcStrictness where
        put_ :: WriteBinHandle -> SrcStrictness -> IO ()
    put_ WriteBinHandle
    bh SrcStrictness
    SrcLazy     = WriteBinHandle -> Word8 -> IO ()
    putByte WriteBinHandle
    bh Word8
    0
        put_ WriteBinHandle
    bh SrcStrictness
    SrcStrict   = WriteBinHandle -> Word8 -> IO ()
    putByte WriteBinHandle
    bh Word8
    1
        put_ WriteBinHandle
    bh SrcStrictness
    NoSrcStrict = WriteBinHandle -> Word8 -> IO ()
    putByte WriteBinHandle
    bh Word8
    2

        get :: ReadBinHandle -> IO SrcStrictness
    get ReadBinHandle
    bh =
          do h <- ReadBinHandle -> IO Word8
    getByte ReadBinHandle
    bh
             case h of
               Word8
    0 -> SrcStrictness -> IO SrcStrictness
    forall a. a -> IO a
    forall (m :: * -> *) a. Monad m => a -> m a
    return SrcStrictness
    SrcLazy
               Word8
    1 -> SrcStrictness -> IO SrcStrictness
    forall a. a -> IO a
    forall (m :: * -> *) a. Monad m => a -> m a
    return SrcStrictness
    SrcStrict
               Word8
    _ -> SrcStrictness -> IO SrcStrictness
    forall a. a -> IO a
    forall (m :: * -> *) a. Monad m => a -> m a
    return SrcStrictness
    NoSrcStrict

    instance Binary SrcUnpackedness where
        put_ :: WriteBinHandle -> SrcUnpackedness -> IO ()
    put_ WriteBinHandle
    bh SrcUnpackedness
    SrcNoUnpack = WriteBinHandle -> Word8 -> IO ()
    putByte WriteBinHandle
    bh Word8
    0
        put_ WriteBinHandle
    bh SrcUnpackedness
    SrcUnpack   = WriteBinHandle -> Word8 -> IO ()
    putByte WriteBinHandle
    bh Word8
    1
        put_ WriteBinHandle
    bh SrcUnpackedness
    NoSrcUnpack = WriteBinHandle -> Word8 -> IO ()
    putByte WriteBinHandle
    bh Word8
    2

        get :: ReadBinHandle -> IO SrcUnpackedness
    get ReadBinHandle
    bh =
          do h <- ReadBinHandle -> IO Word8
    getByte ReadBinHandle
    bh
             case h of
               Word8
    0 -> SrcUnpackedness -> IO SrcUnpackedness
    forall a. a -> IO a
    forall (m :: * -> *) a. Monad m => a -> m a
    return SrcUnpackedness
    SrcNoUnpack
               Word8
    1 -> SrcUnpackedness -> IO SrcUnpackedness
    forall a. a -> IO a
    forall (m :: * -> *) a. Monad m => a -> m a
    return SrcUnpackedness
    SrcUnpack
               Word8
    _ -> SrcUnpackedness -> IO SrcUnpackedness
    forall a. a -> IO a
    forall (m :: * -> *) a. Monad m => a -> m a
    return SrcUnpackedness
    NoSrcUnpack

    -- | Compare strictness annotations
    eqHsBang :: HsImplBang -> HsImplBang -> Bool
    eqHsBang :: HsImplBang -> HsImplBang -> Bool
    eqHsBang HsImplBang
    HsLazy               HsImplBang
    HsLazy              = Bool
    True
    eqHsBang (HsStrict Bool
    _)         (HsStrict Bool
    _)        = Bool
    True
    eqHsBang (HsUnpack Maybe Coercion
    Nothing)   (HsUnpack Maybe Coercion
    Nothing)  = Bool
    True
    eqHsBang (HsUnpack (Just Coercion
    c1)) (HsUnpack (Just Coercion
    c2))
      = HasCallStack => Type -> Type -> Bool
    Type -> Type -> Bool
    eqType (Coercion -> Type
    coercionType Coercion
    c1) (Coercion -> Type
    coercionType Coercion
    c2)
    eqHsBang HsImplBang
    _ HsImplBang
    _                                       = Bool
    False

    isBanged :: HsImplBang -> Bool
    isBanged :: HsImplBang -> Bool
    isBanged (HsUnpack {}) = Bool
    True
    isBanged (HsStrict {}) = Bool
    True
    isBanged HsImplBang
    HsLazy        = Bool
    False

    isSrcStrict :: SrcStrictness -> Bool
    isSrcStrict :: SrcStrictness -> Bool
    isSrcStrict SrcStrictness
    SrcStrict = Bool
    True
    isSrcStrict SrcStrictness
    _ = Bool
    False

    isSrcUnpacked :: SrcUnpackedness -> Bool
    isSrcUnpacked :: SrcUnpackedness -> Bool
    isSrcUnpacked SrcUnpackedness
    SrcUnpack = Bool
    True
    isSrcUnpacked SrcUnpackedness
    _ = Bool
    False

    isMarkedStrict :: StrictnessMark -> Bool
    isMarkedStrict :: StrictnessMark -> Bool
    isMarkedStrict StrictnessMark
    NotMarkedStrict = Bool
    False
    isMarkedStrict StrictnessMark
    _               = Bool
    True   -- All others are strict

    cbvFromStrictMark :: StrictnessMark -> CbvMark
    cbvFromStrictMark :: StrictnessMark -> CbvMark
    cbvFromStrictMark StrictnessMark
    NotMarkedStrict = CbvMark
    NotMarkedCbv
    cbvFromStrictMark StrictnessMark
    MarkedStrict = CbvMark
    MarkedCbv

    {- *********************************************************************
    *                                                                      *
    \subsection{Construction}
    *                                                                      *
    ********************************************************************* -}

    -- | Build a new data constructor
    mkDataCon :: Name
              -> Bool           -- ^ Is the constructor declared infix?
              -> TyConRepName   -- ^  TyConRepName for the promoted TyCon
              -> [HsSrcBang]    -- ^ Strictness/unpack annotations, from user
              -> [FieldLabel]   -- ^ Field labels for the constructor,
                                -- if it is a record, otherwise empty
              -> [TyVar]        -- ^ Universals.
              -> [TyCoVar]      -- ^ Existentials.
              -> ConcreteTyVars
                                    -- ^ TyVars which must be instantiated with
                                    -- concrete types
              -> [InvisTVBinder]    -- ^ User-written 'TyVarBinder's.
                                    --   These must be Inferred/Specified.
                                    --   See @Note [TyVarBinders in DataCons]@
              -> [EqSpec]           -- ^ GADT equalities
              -> KnotTied ThetaType -- ^ Theta-type occurring before the arguments proper
              -> [KnotTied (Scaled Type)]    -- ^ Original argument types
              -> KnotTied Type      -- ^ Original result type
              -> PromDataConInfo    -- ^ See comments on 'GHC.Core.TyCon.PromDataConInfo'
              -> KnotTied TyCon     -- ^ Representation type constructor
              -> ConTag             -- ^ Constructor tag
              -> ThetaType          -- ^ The "stupid theta", context of the data
                                    -- declaration e.g. @data Eq a => T a ...@
              -> Id                 -- ^ Worker Id
              -> DataConRep         -- ^ Representation
              -> DataCon
      -- Can get the tag from the TyCon

    mkDataCon :: Name
    -> Bool
    -> Name
    -> [HsSrcBang]
    -> [FieldLabel]
    -> [TyVar]
    -> [TyVar]
    -> ConcreteTyVars
    -> [InvisTVBinder]
    -> [EqSpec]
    -> [Type]
    -> [Scaled Type]
    -> Type
    -> PromDataConInfo
    -> TyCon
    -> Arity
    -> [Type]
    -> TyVar
    -> DataConRep
    -> DataCon
    mkDataCon Name
    name Bool
    declared_infix Name
    prom_info
              [HsSrcBang]
    arg_stricts   -- Must match orig_arg_tys 1-1
              [FieldLabel]
    fields
              [TyVar]
    univ_tvs [TyVar]
    ex_tvs ConcreteTyVars
    conc_tvs [InvisTVBinder]
    user_tvbs
              [EqSpec]
    eq_spec [Type]
    theta
              [Scaled Type]
    orig_arg_tys Type
    orig_res_ty PromDataConInfo
    rep_info TyCon
    rep_tycon Arity
    tag
              [Type]
    stupid_theta TyVar
    work_id DataConRep
    rep
    -- Warning: mkDataCon is not a good place to check certain invariants.
    -- If the programmer writes the wrong result type in the decl, thus:
    --      data T a where { MkT :: S }
    -- then it's possible that the univ_tvs may hit an assertion failure
    -- if you pull on univ_tvs.  This case is checked by checkValidDataCon,
    -- so the error is detected properly... it's just that assertions here
    -- are a little dodgy.

      = DataCon
    con
      where
        is_vanilla :: Bool
    is_vanilla = [TyVar] -> Bool
    forall a. [a] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null [TyVar]
    ex_tvs Bool -> Bool -> Bool
    && [EqSpec] -> Bool
    forall a. [a] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null [EqSpec]
    eq_spec Bool -> Bool -> Bool
    && [Type] -> Bool
    forall a. [a] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null [Type]
    theta

        con :: DataCon
    con = MkData {dcName :: Name
    dcName = Name
    name, dcUnique :: Unique
    dcUnique = Name -> Unique
    nameUnique Name
    name,
                      dcVanilla :: Bool
    dcVanilla = Bool
    is_vanilla, dcInfix :: Bool
    dcInfix = Bool
    declared_infix,
                      dcUnivTyVars :: [TyVar]
    dcUnivTyVars = [TyVar]
    univ_tvs,
                      dcExTyCoVars :: [TyVar]
    dcExTyCoVars = [TyVar]
    ex_tvs,
                      dcConcreteTyVars :: ConcreteTyVars
    dcConcreteTyVars = ConcreteTyVars
    conc_tvs,
                      dcUserTyVarBinders :: [InvisTVBinder]
    dcUserTyVarBinders = [InvisTVBinder]
    user_tvbs,
                      dcEqSpec :: [EqSpec]
    dcEqSpec = [EqSpec]
    eq_spec,
                      dcOtherTheta :: [Type]
    dcOtherTheta = [Type]
    theta,
                      dcStupidTheta :: [Type]
    dcStupidTheta = [Type]
    stupid_theta,
                      dcOrigArgTys :: [Scaled Type]
    dcOrigArgTys = [Scaled Type]
    orig_arg_tys, dcOrigResTy :: Type
    dcOrigResTy = Type
    orig_res_ty,
                      dcRepTyCon :: TyCon
    dcRepTyCon = TyCon
    rep_tycon,
                      dcSrcBangs :: [HsSrcBang]
    dcSrcBangs = [HsSrcBang]
    arg_stricts,
                      dcFields :: [FieldLabel]
    dcFields = [FieldLabel]
    fields, dcTag :: Arity
    dcTag = Arity
    tag, dcRepType :: Type
    dcRepType = Type
    rep_ty,
                      dcWorkId :: TyVar
    dcWorkId = TyVar
    work_id,
                      dcRep :: DataConRep
    dcRep = DataConRep
    rep,
                      dcSourceArity :: Arity
    dcSourceArity = [Scaled Type] -> Arity
    forall a. [a] -> Arity
    forall (t :: * -> *) a. Foldable t => t a -> Arity
    length [Scaled Type]
    orig_arg_tys,
                      dcRepArity :: Arity
    dcRepArity = [Scaled Type] -> Arity
    forall a. [a] -> Arity
    forall (t :: * -> *) a. Foldable t => t a -> Arity
    length [Scaled Type]
    rep_arg_tys Arity -> Arity -> Arity
    forall a. Num a => a -> a -> a
    + (TyVar -> Bool) -> [TyVar] -> Arity
    forall a. (a -> Bool) -> [a] -> Arity
    count TyVar -> Bool
    isCoVar [TyVar]
    ex_tvs,
                      dcPromoted :: TyCon
    dcPromoted = TyCon
    promoted }

            -- The 'arg_stricts' passed to mkDataCon are simply those for the
            -- source-language arguments.  We add extra ones for the
            -- dictionary arguments right here.

        rep_arg_tys :: [Scaled Type]
    rep_arg_tys = DataCon -> [Scaled Type]
    dataConRepArgTys DataCon
    con

        rep_ty :: Type
    rep_ty =
          case DataConRep
    rep of
            -- If the DataCon has no wrapper, then the worker's type *is* the
            -- user-facing type, so we can simply use dataConWrapperType.
            DataConRep
    NoDataConRep -> DataCon -> Type
    dataConWrapperType DataCon
    con
            -- If the DataCon has a wrapper, then the worker's type is never seen
            -- by the user. The visibilities we pick do not matter here.
            DCR{} -> [TyVar] -> Type -> Type
    mkInfForAllTys [TyVar]
    univ_tvs (Type -> Type) -> Type -> Type
    forall a b. (a -> b) -> a -> b
    $ [TyVar] -> Type -> Type
    mkTyCoInvForAllTys [TyVar]
    ex_tvs (Type -> Type) -> Type -> Type
    forall a b. (a -> b) -> a -> b
    $
                     [Scaled Type] -> Type -> Type
    mkScaledFunctionTys [Scaled Type]
    rep_arg_tys (Type -> Type) -> Type -> Type
    forall a b. (a -> b) -> a -> b
    $
                     TyCon -> [Type] -> Type
    mkTyConApp TyCon
    rep_tycon ([TyVar] -> [Type]
    mkTyVarTys [TyVar]
    univ_tvs)
                     -- res_arg_tys is a mixture of TypeLike and ConstraintLike,
                     -- so we don't know which FunTyFlag to use
                     -- Hence using mkScaledFunctionTys.

          -- See Note [Promoted data constructors] in GHC.Core.TyCon
        prom_tv_bndrs :: [TyConBinder]
    prom_tv_bndrs = [ ForAllTyFlag -> TyVar -> TyConBinder
    mkNamedTyConBinder (Specificity -> ForAllTyFlag
    Invisible Specificity
    spec) TyVar
    tv
                        | Bndr TyVar
    tv Specificity
    spec <- [InvisTVBinder]
    user_tvbs ]

        fresh_names :: [Name]
    fresh_names = [Name] -> [Name]
    freshNames ((InvisTVBinder -> Name) -> [InvisTVBinder] -> [Name]
    forall a b. (a -> b) -> [a] -> [b]
    map InvisTVBinder -> Name
    forall a. NamedThing a => a -> Name
    getName [InvisTVBinder]
    user_tvbs)
          -- fresh_names: make sure that the "anonymous" tyvars don't
          -- clash in name or unique with the universal/existential ones.
          -- Tiresome!  And unnecessary because these tyvars are never looked at
        prom_arg_bndrs :: [TyConBinder]
    prom_arg_bndrs   = [ TyVar -> TyConBinder
    mkAnonTyConBinder (Name -> Type -> TyVar
    mkTyVar Name
    n Type
    t)
         {- Visible -}     | (Name
    n,Type
    t) <- [Type] -> [Name] -> [Name]
    forall b a. [b] -> [a] -> [a]
    dropList [Type]
    theta [Name]
    fresh_names [Name] -> [Type] -> [(Name, Type)]
    forall a b. [a] -> [b] -> [(a, b)]
    `zip` (Scaled Type -> Type) -> [Scaled Type] -> [Type]
    forall a b. (a -> b) -> [a] -> [b]
    map Scaled Type -> Type
    forall a. Scaled a -> a
    scaledThing [Scaled Type]
    orig_arg_tys ]
        prom_bndrs :: [TyConBinder]
    prom_bndrs       = [TyConBinder]
    prom_tv_bndrs [TyConBinder] -> [TyConBinder] -> [TyConBinder]
    forall a. [a] -> [a] -> [a]
    ++ [TyConBinder]
    prom_arg_bndrs
        prom_res_kind :: Type
    prom_res_kind    = Type
    orig_res_ty
        promoted :: TyCon
    promoted         = DataCon
    -> Name
    -> Name
    -> [TyConBinder]
    -> Type
    -> [Role]
    -> PromDataConInfo
    -> TyCon
    mkPromotedDataCon DataCon
    con Name
    name Name
    prom_info [TyConBinder]
    prom_bndrs
                                             Type
    prom_res_kind [Role]
    roles PromDataConInfo
    rep_info

        roles :: [Role]
    roles = (TyVar -> Role) -> [TyVar] -> [Role]
    forall a b. (a -> b) -> [a] -> [b]
    map (\TyVar
    tv -> if TyVar -> Bool
    isTyVar TyVar
    tv then Role
    Nominal else Role
    Phantom)
                    ([TyVar]
    univ_tvs [TyVar] -> [TyVar] -> [TyVar]
    forall a. [a] -> [a] -> [a]
    ++ [TyVar]
    ex_tvs)
                [Role] -> [Role] -> [Role]
    forall a. [a] -> [a] -> [a]
    ++ (Type -> Role) -> [Type] -> [Role]
    forall a b. (a -> b) -> [a] -> [b]
    map (Role -> Type -> Role
    forall a b. a -> b -> a
    const Role
    Representational) ([Type]
    theta [Type] -> [Type] -> [Type]
    forall a. [a] -> [a] -> [a]
    ++ (Scaled Type -> Type) -> [Scaled Type] -> [Type]
    forall a b. (a -> b) -> [a] -> [b]
    map Scaled Type -> Type
    forall a. Scaled a -> a
    scaledThing [Scaled Type]
    orig_arg_tys)

    freshNames :: [Name] -> [Name]
    -- Make an infinite list of Names whose Uniques and OccNames
    -- differ from those in the 'avoid' list
    freshNames :: [Name] -> [Name]
    freshNames [Name]
    avoids
      = [ Unique -> OccName -> Name
    mkSystemName Unique
    uniq OccName
    occ
        | Arity
    n <- [Arity
    0..]
        , let uniq :: Unique
    uniq = Arity -> Unique
    mkAlphaTyVarUnique Arity
    n
              occ :: OccName
    occ = FastString -> OccName
    mkTyVarOccFS (String -> FastString
    mkFastString (Char
    'x' Char -> String -> String
    forall a. a -> [a] -> [a]
    : Arity -> String
    forall a. Show a => a -> String
    show Arity
    n))

        , Bool -> Bool
    not (Unique
    uniq Unique -> UniqueSet -> Bool
    `memberUniqueSet` UniqueSet
    avoid_uniqs)
        , Bool -> Bool
    not (OccName
    occ OccName -> OccSet -> Bool
    `elemOccSet` OccSet
    avoid_occs) ]

      where
        avoid_uniqs :: UniqueSet
        avoid_uniqs :: UniqueSet
    avoid_uniqs = [Unique] -> UniqueSet
    fromListUniqueSet ((Name -> Unique) -> [Name] -> [Unique]
    forall a b. (a -> b) -> [a] -> [b]
    map Name -> Unique
    forall a. Uniquable a => a -> Unique
    getUnique [Name]
    avoids)

        avoid_occs :: OccSet
        avoid_occs :: OccSet
    avoid_occs = [OccName] -> OccSet
    mkOccSet ((Name -> OccName) -> [Name] -> [OccName]
    forall a b. (a -> b) -> [a] -> [b]
    map Name -> OccName
    forall a. NamedThing a => a -> OccName
    getOccName [Name]
    avoids)

    -- | The 'Name' of the 'DataCon', giving it a unique, rooted identification
    dataConName :: DataCon -> Name
    dataConName :: DataCon -> Name
    dataConName = DataCon -> Name
    dcName

    -- | The tag used for ordering 'DataCon's
    dataConTag :: DataCon -> ConTag
    dataConTag :: DataCon -> Arity
    dataConTag  = DataCon -> Arity
    dcTag

    dataConTagZ :: DataCon -> ConTagZ
    dataConTagZ :: DataCon -> Arity
    dataConTagZ DataCon
    con = DataCon -> Arity
    dataConTag DataCon
    con Arity -> Arity -> Arity
    forall a. Num a => a -> a -> a
    - Arity
    fIRST_TAG

    -- | The type constructor that we are building via this data constructor
    dataConTyCon :: DataCon -> TyCon
    dataConTyCon :: DataCon -> TyCon
    dataConTyCon = DataCon -> TyCon
    dcRepTyCon

    -- | The original type constructor used in the definition of this data
    -- constructor.  In case of a data family instance, that will be the family
    -- type constructor.
    dataConOrigTyCon :: DataCon -> TyCon
    dataConOrigTyCon :: DataCon -> TyCon
    dataConOrigTyCon DataCon
    dc
      | Just (TyCon
    tc, [Type]
    _) <- TyCon -> Maybe (TyCon, [Type])
    tyConFamInst_maybe (DataCon -> TyCon
    dcRepTyCon DataCon
    dc) = TyCon
    tc
      | Bool
    otherwise                                          = DataCon -> TyCon
    dcRepTyCon DataCon
    dc

    -- | The representation type of the data constructor, i.e. the sort
    -- type that will represent values of this type at runtime
    dataConRepType :: DataCon -> Type
    dataConRepType :: DataCon -> Type
    dataConRepType = DataCon -> Type
    dcRepType

    -- | Should the 'DataCon' be presented infix?
    dataConIsInfix :: DataCon -> Bool
    dataConIsInfix :: DataCon -> Bool
    dataConIsInfix = DataCon -> Bool
    dcInfix

    -- | The universally-quantified type variables of the constructor
    dataConUnivTyVars :: DataCon -> [TyVar]
    dataConUnivTyVars :: DataCon -> [TyVar]
    dataConUnivTyVars (MkData { dcUnivTyVars :: DataCon -> [TyVar]
    dcUnivTyVars = [TyVar]
    tvbs }) = [TyVar]
    tvbs

    -- | The existentially-quantified type/coercion variables of the constructor
    -- including dependent (kind-) GADT equalities
    dataConExTyCoVars :: DataCon -> [TyCoVar]
    dataConExTyCoVars :: DataCon -> [TyVar]
    dataConExTyCoVars (MkData { dcExTyCoVars :: DataCon -> [TyVar]
    dcExTyCoVars = [TyVar]
    tvbs }) = [TyVar]
    tvbs

    -- | Both the universal and existential type/coercion variables of the constructor
    dataConUnivAndExTyCoVars :: DataCon -> [TyCoVar]
    dataConUnivAndExTyCoVars :: DataCon -> [TyVar]
    dataConUnivAndExTyCoVars (MkData { dcUnivTyVars :: DataCon -> [TyVar]
    dcUnivTyVars = [TyVar]
    univ_tvs, dcExTyCoVars :: DataCon -> [TyVar]
    dcExTyCoVars = [TyVar]
    ex_tvs })
      = [TyVar]
    univ_tvs [TyVar] -> [TyVar] -> [TyVar]
    forall a. [a] -> [a] -> [a]
    ++ [TyVar]
    ex_tvs

    -- | Which type variables of this data constructor that must be
    -- instantiated to concrete types?
    -- For example: the RuntimeRep variables of unboxed tuples and unboxed sums.
    --
    -- See Note [Representation-polymorphism checking built-ins]
    -- in GHC.Tc.Utils.Concrete
    dataConConcreteTyVars :: DataCon -> ConcreteTyVars
    dataConConcreteTyVars :: DataCon -> ConcreteTyVars
    dataConConcreteTyVars (MkData { dcConcreteTyVars :: DataCon -> ConcreteTyVars
    dcConcreteTyVars = ConcreteTyVars
    concs }) = ConcreteTyVars
    concs

    -- See Note [DataCon user type variable binders]
    -- | The type variables of the constructor, in the order the user wrote them
    dataConUserTyVars :: DataCon -> [TyVar]
    dataConUserTyVars :: DataCon -> [TyVar]
    dataConUserTyVars (MkData { dcUserTyVarBinders :: DataCon -> [InvisTVBinder]
    dcUserTyVarBinders = [InvisTVBinder]
    tvbs }) = [InvisTVBinder] -> [TyVar]
    forall tv argf. [VarBndr tv argf] -> [tv]
    binderVars [InvisTVBinder]
    tvbs

    -- See Note [DataCon user type variable binders]
    -- | 'InvisTVBinder's for the type variables of the constructor, in the order the
    -- user wrote them
    dataConUserTyVarBinders :: DataCon -> [InvisTVBinder]
    dataConUserTyVarBinders :: DataCon -> [InvisTVBinder]
    dataConUserTyVarBinders = DataCon -> [InvisTVBinder]
    dcUserTyVarBinders

    -- | Dependent (kind-level) equalities in a constructor.
    -- There are extracted from the existential variables.
    -- See Note [Existential coercion variables]
    dataConKindEqSpec :: DataCon -> [EqSpec]
    dataConKindEqSpec :: DataCon -> [EqSpec]
    dataConKindEqSpec (MkData {dcExTyCoVars :: DataCon -> [TyVar]
    dcExTyCoVars = [TyVar]
    ex_tcvs})
      -- It is used in 'dataConEqSpec' (maybe also 'dataConFullSig' in the future),
      -- which are frequently used functions.
      -- For now (Aug 2018) this function always return empty set as we don't really
      -- have coercion variables.
      -- In the future when we do, we might want to cache this information in DataCon
      -- so it won't be computed every time when aforementioned functions are called.
      = [ TyVar -> Type -> EqSpec
    EqSpec TyVar
    tv Type
    ty
        | TyVar
    cv <- [TyVar]
    ex_tcvs
        , TyVar -> Bool
    isCoVar TyVar
    cv
        , let (Type
    ty1, Type
    ty, Role
    _) = HasDebugCallStack => TyVar -> (Type, Type, Role)
    TyVar -> (Type, Type, Role)
    coVarTypesRole TyVar
    cv
              tv :: TyVar
    tv = HasDebugCallStack => Type -> TyVar
    Type -> TyVar
    getTyVar Type
    ty1
        ]

    -- | The *full* constraints on the constructor type, including dependent GADT
    -- equalities.
    dataConTheta :: DataCon -> ThetaType
    dataConTheta :: DataCon -> [Type]
    dataConTheta con :: DataCon
    con@(MkData { dcEqSpec :: DataCon -> [EqSpec]
    dcEqSpec = [EqSpec]
    eq_spec, dcOtherTheta :: DataCon -> [Type]
    dcOtherTheta = [Type]
    theta })
      = [EqSpec] -> [Type]
    eqSpecPreds (DataCon -> [EqSpec]
    dataConKindEqSpec DataCon
    con [EqSpec] -> [EqSpec] -> [EqSpec]
    forall a. [a] -> [a] -> [a]
    ++ [EqSpec]
    eq_spec) [Type] -> [Type] -> [Type]
    forall a. [a] -> [a] -> [a]
    ++ [Type]
    theta

    -- | Get the Id of the 'DataCon' worker: a function that is the "actual"
    -- constructor and has no top level binding in the program. The type may
    -- be different from the obvious one written in the source program. Panics
    -- if there is no such 'Id' for this 'DataCon'
    dataConWorkId :: DataCon -> Id
    dataConWorkId :: DataCon -> TyVar
    dataConWorkId DataCon
    dc = DataCon -> TyVar
    dcWorkId DataCon
    dc

    -- | Get the Id of the 'DataCon' wrapper: a function that wraps the "actual"
    -- constructor so it has the type visible in the source program: c.f.
    -- 'dataConWorkId'.
    -- Returns Nothing if there is no wrapper, which occurs for an algebraic data
    -- constructor and also for a newtype (whose constructor is inlined
    -- compulsorily)
    dataConWrapId_maybe :: DataCon -> Maybe Id
    dataConWrapId_maybe :: DataCon -> Maybe TyVar
    dataConWrapId_maybe DataCon
    dc = case DataCon -> DataConRep
    dcRep DataCon
    dc of
                               DataConRep
    NoDataConRep -> Maybe TyVar
    forall a. Maybe a
    Nothing
                               DCR { dcr_wrap_id :: DataConRep -> TyVar
    dcr_wrap_id = TyVar
    wrap_id } -> TyVar -> Maybe TyVar
    forall a. a -> Maybe a
    Just TyVar
    wrap_id

    -- | Returns an Id which looks like the Haskell-source constructor by using
    -- the wrapper if it exists (see 'dataConWrapId_maybe') and failing over to
    -- the worker (see 'dataConWorkId')
    dataConWrapId :: DataCon -> Id
    dataConWrapId :: DataCon -> TyVar
    dataConWrapId DataCon
    dc = case DataCon -> DataConRep
    dcRep DataCon
    dc of
                         DataConRep
    NoDataConRep-> DataCon -> TyVar
    dcWorkId DataCon
    dc    -- worker=wrapper
                         DCR { dcr_wrap_id :: DataConRep -> TyVar
    dcr_wrap_id = TyVar
    wrap_id } -> TyVar
    wrap_id

    -- | Find all the 'Id's implicitly brought into scope by the data constructor. Currently,
    -- the union of the 'dataConWorkId' and the 'dataConWrapId'
    dataConImplicitTyThings :: DataCon -> [TyThing]
    dataConImplicitTyThings :: DataCon -> [TyThing]
    dataConImplicitTyThings (MkData { dcWorkId :: DataCon -> TyVar
    dcWorkId = TyVar
    work, dcRep :: DataCon -> DataConRep
    dcRep = DataConRep
    rep })
      = [TyVar -> TyThing
    mkAnId TyVar
    work] [TyThing] -> [TyThing] -> [TyThing]
    forall a. [a] -> [a] -> [a]
    ++ [TyThing]
    wrap_ids
      where
        wrap_ids :: [TyThing]
    wrap_ids = case DataConRep
    rep of
                     DataConRep
    NoDataConRep               -> []
                     DCR { dcr_wrap_id :: DataConRep -> TyVar
    dcr_wrap_id = TyVar
    wrap } -> [TyVar -> TyThing
    mkAnId TyVar
    wrap]

    -- | The labels for the fields of this particular 'DataCon'
    dataConFieldLabels :: DataCon -> [FieldLabel]
    dataConFieldLabels :: DataCon -> [FieldLabel]
    dataConFieldLabels = DataCon -> [FieldLabel]
    dcFields

    -- | Extract the type for any given labelled field of the 'DataCon'
    dataConFieldType :: DataCon -> FieldLabelString -> Type
    dataConFieldType :: DataCon -> FieldLabelString -> Type
    dataConFieldType DataCon
    con FieldLabelString
    label = case DataCon -> FieldLabelString -> Maybe (FieldLabel, Type)
    dataConFieldType_maybe DataCon
    con FieldLabelString
    label of
          Just (FieldLabel
    _, Type
    ty) -> Type
    ty
          Maybe (FieldLabel, Type)
    Nothing      -> String -> SDoc -> Type
    forall a. HasCallStack => String -> SDoc -> a
    pprPanic String
    "dataConFieldType" (DataCon -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr DataCon
    con SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> FieldLabelString -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr FieldLabelString
    label)

    -- | Extract the label and type for any given labelled field of the
    -- 'DataCon', or return 'Nothing' if the field does not belong to it
    dataConFieldType_maybe :: DataCon -> FieldLabelString
                           -> Maybe (FieldLabel, Type)
    dataConFieldType_maybe :: DataCon -> FieldLabelString -> Maybe (FieldLabel, Type)
    dataConFieldType_maybe DataCon
    con FieldLabelString
    label
      = ((FieldLabel, Type) -> Bool)
    -> [(FieldLabel, Type)] -> Maybe (FieldLabel, Type)
    forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Maybe a
    find ((FieldLabelString -> FieldLabelString -> Bool
    forall a. Eq a => a -> a -> Bool
    == FieldLabelString
    label) (FieldLabelString -> Bool)
    -> ((FieldLabel, Type) -> FieldLabelString)
    -> (FieldLabel, Type)
    -> Bool
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . FieldLabel -> FieldLabelString
    flLabel (FieldLabel -> FieldLabelString)
    -> ((FieldLabel, Type) -> FieldLabel)
    -> (FieldLabel, Type)
    -> FieldLabelString
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . (FieldLabel, Type) -> FieldLabel
    forall a b. (a, b) -> a
    fst) (DataCon -> [FieldLabel]
    dcFields DataCon
    con [FieldLabel] -> [Type] -> [(FieldLabel, Type)]
    forall a b. [a] -> [b] -> [(a, b)]
    `zip` (Scaled Type -> Type
    forall a. Scaled a -> a
    scaledThing (Scaled Type -> Type) -> [Scaled Type] -> [Type]
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    <$> DataCon -> [Scaled Type]
    dcOrigArgTys DataCon
    con))

    -- | Strictness/unpack annotations, from user; or, for imported
    -- DataCons, from the interface file
    -- The list is in one-to-one correspondence with the arity of the 'DataCon'

    dataConSrcBangs :: DataCon -> [HsSrcBang]
    dataConSrcBangs :: DataCon -> [HsSrcBang]
    dataConSrcBangs = DataCon -> [HsSrcBang]
    dcSrcBangs

    -- | Source-level arity of the data constructor
    dataConSourceArity :: DataCon -> Arity
    dataConSourceArity :: DataCon -> Arity
    dataConSourceArity (MkData { dcSourceArity :: DataCon -> Arity
    dcSourceArity = Arity
    arity }) = Arity
    arity

    -- | Gives the number of value arguments (including zero-width coercions)
    -- stored by the given `DataCon`'s worker in its Core representation. This may
    -- differ from the number of arguments that appear in the source code; see also
    -- Note [DataCon arities]
    dataConRepArity :: DataCon -> Arity
    dataConRepArity :: DataCon -> Arity
    dataConRepArity (MkData { dcRepArity :: DataCon -> Arity
    dcRepArity = Arity
    arity }) = Arity
    arity

    -- | Return whether there are any argument types for this 'DataCon's original source type
    -- See Note [DataCon arities]
    isNullarySrcDataCon :: DataCon -> Bool
    isNullarySrcDataCon :: DataCon -> Bool
    isNullarySrcDataCon DataCon
    dc = DataCon -> Arity
    dataConSourceArity DataCon
    dc Arity -> Arity -> Bool
    forall a. Eq a => a -> a -> Bool
    == Arity
    0

    -- | Return whether this `DataCon`'s worker, in its Core representation, takes
    -- any value arguments.
    --
    -- In particular, remember that we include coercion arguments in the arity of
    -- the Core representation of the `DataCon` -- both lifted and unlifted
    -- coercions, despite the latter having zero-width runtime representation.
    --
    -- See also Note [DataCon arities].
    isNullaryRepDataCon :: DataCon -> Bool
    isNullaryRepDataCon :: DataCon -> Bool
    isNullaryRepDataCon DataCon
    dc = DataCon -> Arity
    dataConRepArity DataCon
    dc Arity -> Arity -> Bool
    forall a. Eq a => a -> a -> Bool
    == Arity
    0

    dataConRepStrictness :: DataCon -> [StrictnessMark]
    -- ^ Give the demands on the arguments of a
    -- Core constructor application (Con dc args)
    dataConRepStrictness :: DataCon -> [StrictnessMark]
    dataConRepStrictness DataCon
    dc = case DataCon -> DataConRep
    dcRep DataCon
    dc of
                                DataConRep
    NoDataConRep -> [StrictnessMark
    NotMarkedStrict | Scaled Type
    _ <- DataCon -> [Scaled Type]
    dataConRepArgTys DataCon
    dc]
                                DCR { dcr_stricts :: DataConRep -> [StrictnessMark]
    dcr_stricts = [StrictnessMark]
    strs } -> [StrictnessMark]
    strs

    dataConImplBangs :: DataCon -> [HsImplBang]
    -- The implementation decisions about the strictness/unpack of each
    -- source program argument to the data constructor
    dataConImplBangs :: DataCon -> [HsImplBang]
    dataConImplBangs DataCon
    dc
      = case DataCon -> DataConRep
    dcRep DataCon
    dc of
          DataConRep
    NoDataConRep              -> Arity -> HsImplBang -> [HsImplBang]
    forall a. Arity -> a -> [a]
    replicate (DataCon -> Arity
    dcSourceArity DataCon
    dc) HsImplBang
    HsLazy
          DCR { dcr_bangs :: DataConRep -> [HsImplBang]
    dcr_bangs = [HsImplBang]
    bangs } -> [HsImplBang]
    bangs

    dataConBoxer :: DataCon -> Maybe DataConBoxer
    dataConBoxer :: DataCon -> Maybe DataConBoxer
    dataConBoxer (MkData { dcRep :: DataCon -> DataConRep
    dcRep = DCR { dcr_boxer :: DataConRep -> DataConBoxer
    dcr_boxer = DataConBoxer
    boxer } }) = DataConBoxer -> Maybe DataConBoxer
    forall a. a -> Maybe a
    Just DataConBoxer
    boxer
    dataConBoxer DataCon
    _ = Maybe DataConBoxer
    forall a. Maybe a
    Nothing

    dataConInstSig
      :: DataCon
      -> [Type]    -- Instantiate the *universal* tyvars with these types
      -> ([TyCoVar], ThetaType, [Type])  -- Return instantiated existentials
                                         -- theta and arg tys
    -- ^ Instantiate the universal tyvars of a data con,
    --   returning
    --     ( instantiated existentials
    --     , instantiated constraints including dependent GADT equalities
    --         which are *also* listed in the instantiated existentials
    --     , instantiated args)
    dataConInstSig :: DataCon -> [Type] -> ([TyVar], [Type], [Type])
    dataConInstSig con :: DataCon
    con@(MkData { dcUnivTyVars :: DataCon -> [TyVar]
    dcUnivTyVars = [TyVar]
    univ_tvs, dcExTyCoVars :: DataCon -> [TyVar]
    dcExTyCoVars = [TyVar]
    ex_tvs
                               , dcOrigArgTys :: DataCon -> [Scaled Type]
    dcOrigArgTys = [Scaled Type]
    arg_tys })
                   [Type]
    univ_tys
      = ( [TyVar]
    ex_tvs'
        , HasDebugCallStack => Subst -> [Type] -> [Type]
    Subst -> [Type] -> [Type]
    substTheta Subst
    subst (DataCon -> [Type]
    dataConTheta DataCon
    con)
        , HasDebugCallStack => Subst -> [Type] -> [Type]
    Subst -> [Type] -> [Type]
    substTys Subst
    subst ((Scaled Type -> Type) -> [Scaled Type] -> [Type]
    forall a b. (a -> b) -> [a] -> [b]
    map Scaled Type -> Type
    forall a. Scaled a -> a
    scaledThing [Scaled Type]
    arg_tys))
      where
        univ_subst :: Subst
    univ_subst = [TyVar] -> [Type] -> Subst
    HasDebugCallStack => [TyVar] -> [Type] -> Subst
    zipTvSubst [TyVar]
    univ_tvs [Type]
    univ_tys
        (Subst
    subst, [TyVar]
    ex_tvs') = HasDebugCallStack => Subst -> [TyVar] -> (Subst, [TyVar])
    Subst -> [TyVar] -> (Subst, [TyVar])
    Type.substVarBndrs Subst
    univ_subst [TyVar]
    ex_tvs

    -- | The \"full signature\" of the 'DataCon' returns, in order:
    --
    -- 1) The result of 'dataConUnivTyVars'
    --
    -- 2) The result of 'dataConExTyCoVars'
    --
    -- 3) The non-dependent GADT equalities.
    --    Dependent GADT equalities are implied by coercion variables in
    --    return value (2).
    --
    -- 4) The other constraints of the data constructor type, excluding GADT
    -- equalities
    --
    -- 5) The original argument types to the 'DataCon' (i.e. before
    --    any change of the representation of the type) with linearity
    --    annotations
    --
    -- 6) The original result type of the 'DataCon'
    dataConFullSig :: DataCon
                   -> ([TyVar], [TyCoVar], [EqSpec], ThetaType, [Scaled Type], Type)
    dataConFullSig :: DataCon
    -> ([TyVar], [TyVar], [EqSpec], [Type], [Scaled Type], Type)
    dataConFullSig (MkData {dcUnivTyVars :: DataCon -> [TyVar]
    dcUnivTyVars = [TyVar]
    univ_tvs, dcExTyCoVars :: DataCon -> [TyVar]
    dcExTyCoVars = [TyVar]
    ex_tvs,
                            dcEqSpec :: DataCon -> [EqSpec]
    dcEqSpec = [EqSpec]
    eq_spec, dcOtherTheta :: DataCon -> [Type]
    dcOtherTheta = [Type]
    theta,
                            dcOrigArgTys :: DataCon -> [Scaled Type]
    dcOrigArgTys = [Scaled Type]
    arg_tys, dcOrigResTy :: DataCon -> Type
    dcOrigResTy = Type
    res_ty})
      = ([TyVar]
    univ_tvs, [TyVar]
    ex_tvs, [EqSpec]
    eq_spec, [Type]
    theta, [Scaled Type]
    arg_tys, Type
    res_ty)

    dataConOrigResTy :: DataCon -> Type
    dataConOrigResTy :: DataCon -> Type
    dataConOrigResTy DataCon
    dc = DataCon -> Type
    dcOrigResTy DataCon
    dc

    -- | The \"stupid theta\" of the 'DataCon', such as @data Eq a@ in:
    --
    -- > data Eq a => T a = ...
    --
    -- See @Note [The stupid context]@.
    dataConStupidTheta :: DataCon -> ThetaType
    dataConStupidTheta :: DataCon -> [Type]
    dataConStupidTheta DataCon
    dc = DataCon -> [Type]
    dcStupidTheta DataCon
    dc

    {-
    Note [Displaying linear fields]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    A constructor with a linear field can be written either as
    MkT :: a %1 -> T a (with -XLinearTypes)
    or
    MkT :: a  -> T a (with -XNoLinearTypes)

    There are three different methods to retrieve a type of a datacon.
    They differ in how linear fields are handled.

    1. dataConWrapperType:
    The type of the wrapper in Core.
    For example, dataConWrapperType for Maybe is a %1 -> Just a.

    2. dataConNonlinearType:
    The type of the constructor, with linear arrows replaced by unrestricted ones.
    Used when we don't want to introduce linear types to user (in holes
    and in types in hie used by haddock).

    3. dataConDisplayType (takes a boolean indicating if -XLinearTypes is enabled):
    The type we'd like to show in error messages, :info and -ddump-types.
    Ideally, it should reflect the type written by the user;
    the function returns a type with arrows that would be required
    to write this constructor under the current setting of -XLinearTypes.
    In principle, this type can be different from the user's source code
    when the value of -XLinearTypes has changed, but we don't
    expect this to cause much trouble.

    Due to internal plumbing in checkValidDataCon, we can't just return a Doc.
    The multiplicity of arrows returned by dataConDisplayType and
    dataConDisplayType is used only for pretty-printing.
    -}

    dataConWrapperType :: DataCon -> Type
    -- ^ The user-declared type of the data constructor
    -- in the nice-to-read form:
    --
    -- > T :: forall a b. a -> b -> T [a]
    --
    -- rather than:
    --
    -- > T :: forall a c. forall b. (c~[a]) => a -> b -> T c
    --
    -- The type variables are quantified in the order that the user wrote them.
    -- See @Note [DataCon user type variable binders]@.
    --
    -- NB: If the constructor is part of a data instance, the result type
    -- mentions the family tycon, not the internal one.
    dataConWrapperType :: DataCon -> Type
    dataConWrapperType (MkData { dcUserTyVarBinders :: DataCon -> [InvisTVBinder]
    dcUserTyVarBinders = [InvisTVBinder]
    user_tvbs,
                                 dcOtherTheta :: DataCon -> [Type]
    dcOtherTheta = [Type]
    theta, dcOrigArgTys :: DataCon -> [Scaled Type]
    dcOrigArgTys = [Scaled Type]
    arg_tys,
                                 dcOrigResTy :: DataCon -> Type
    dcOrigResTy = Type
    res_ty,
                                 dcStupidTheta :: DataCon -> [Type]
    dcStupidTheta = [Type]
    stupid_theta })
      = [InvisTVBinder] -> Type -> Type
    mkInvisForAllTys [InvisTVBinder]
    user_tvbs (Type -> Type) -> Type -> Type
    forall a b. (a -> b) -> a -> b
    $
        [Type] -> Type -> Type
    HasDebugCallStack => [Type] -> Type -> Type
    mkInvisFunTys ([Type]
    stupid_theta [Type] -> [Type] -> [Type]
    forall a. [a] -> [a] -> [a]
    ++ [Type]
    theta) (Type -> Type) -> Type -> Type
    forall a b. (a -> b) -> a -> b
    $
        [Scaled Type] -> Type -> Type
    HasDebugCallStack => [Scaled Type] -> Type -> Type
    mkScaledFunTys [Scaled Type]
    arg_tys (Type -> Type) -> Type -> Type
    forall a b. (a -> b) -> a -> b
    $
        Type
    res_ty

    dataConNonlinearType :: DataCon -> Type
    -- Just like dataConWrapperType, but with the
    -- linearity on the arguments all zapped to Many
    dataConNonlinearType :: DataCon -> Type
    dataConNonlinearType (MkData { dcUserTyVarBinders :: DataCon -> [InvisTVBinder]
    dcUserTyVarBinders = [InvisTVBinder]
    user_tvbs,
                                   dcOtherTheta :: DataCon -> [Type]
    dcOtherTheta = [Type]
    theta, dcOrigArgTys :: DataCon -> [Scaled Type]
    dcOrigArgTys = [Scaled Type]
    arg_tys,
                                   dcOrigResTy :: DataCon -> Type
    dcOrigResTy = Type
    res_ty,
                                   dcStupidTheta :: DataCon -> [Type]
    dcStupidTheta = [Type]
    stupid_theta })
      = [InvisTVBinder] -> Type -> Type
    mkInvisForAllTys [InvisTVBinder]
    user_tvbs (Type -> Type) -> Type -> Type
    forall a b. (a -> b) -> a -> b
    $
        [Type] -> Type -> Type
    HasDebugCallStack => [Type] -> Type -> Type
    mkInvisFunTys ([Type]
    stupid_theta [Type] -> [Type] -> [Type]
    forall a. [a] -> [a] -> [a]
    ++ [Type]
    theta) (Type -> Type) -> Type -> Type
    forall a b. (a -> b) -> a -> b
    $
        [Scaled Type] -> Type -> Type
    HasDebugCallStack => [Scaled Type] -> Type -> Type
    mkScaledFunTys [Scaled Type]
    arg_tys' (Type -> Type) -> Type -> Type
    forall a b. (a -> b) -> a -> b
    $
        Type
    res_ty
      where
        arg_tys' :: [Scaled Type]
    arg_tys' = (Scaled Type -> Scaled Type) -> [Scaled Type] -> [Scaled Type]
    forall a b. (a -> b) -> [a] -> [b]
    map (\(Scaled Type
    w Type
    t) -> Type -> Type -> Scaled Type
    forall a. Type -> a -> Scaled a
    Scaled (case Type
    w of Type
    OneTy -> Type
    ManyTy; Type
    _ -> Type
    w) Type
    t) [Scaled Type]
    arg_tys

    dataConDisplayType :: Bool -> DataCon -> Type
    dataConDisplayType :: Bool -> DataCon -> Type
    dataConDisplayType Bool
    show_linear_types DataCon
    dc
      = if Bool
    show_linear_types
        then DataCon -> Type
    dataConWrapperType DataCon
    dc
        else DataCon -> Type
    dataConNonlinearType DataCon
    dc

    -- | Finds the instantiated types of the arguments required to construct a
    -- 'DataCon' representation
    -- NB: these INCLUDE any dictionary args
    --     but EXCLUDE the data-declaration context, which is discarded
    -- It's all post-flattening etc; this is a representation type
    dataConInstArgTys :: DataCon    -- ^ A datacon with no existentials or equality constraints
                                    -- However, it can have a dcTheta (notably it can be a
                                    -- class dictionary, with superclasses)
                      -> [Type]     -- ^ Instantiated at these types
                      -> [Scaled Type]
    dataConInstArgTys :: DataCon -> [Type] -> [Scaled Type]
    dataConInstArgTys dc :: DataCon
    dc@(MkData {dcUnivTyVars :: DataCon -> [TyVar]
    dcUnivTyVars = [TyVar]
    univ_tvs,
                                  dcExTyCoVars :: DataCon -> [TyVar]
    dcExTyCoVars = [TyVar]
    ex_tvs}) [Type]
    inst_tys
     = Bool -> SDoc -> [Scaled Type] -> [Scaled Type]
    forall a. HasCallStack => Bool -> SDoc -> a -> a
    assertPpr ([TyVar]
    univ_tvs [TyVar] -> [Type] -> Bool
    forall a b. [a] -> [b] -> Bool
    `equalLength` [Type]
    inst_tys)
                 (String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "dataConInstArgTys" SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> DataCon -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr DataCon
    dc SDoc -> SDoc -> SDoc
    forall doc. IsDoc doc => doc -> doc -> doc
    $$ [TyVar] -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr [TyVar]
    univ_tvs SDoc -> SDoc -> SDoc
    forall doc. IsDoc doc => doc -> doc -> doc
    $$ [Type] -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr [Type]
    inst_tys) ([Scaled Type] -> [Scaled Type]) -> [Scaled Type] -> [Scaled Type]
    forall a b. (a -> b) -> a -> b
    $
       Bool -> SDoc -> [Scaled Type] -> [Scaled Type]
    forall a. HasCallStack => Bool -> SDoc -> a -> a
    assertPpr ([TyVar] -> Bool
    forall a. [a] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null [TyVar]
    ex_tvs) (DataCon -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr DataCon
    dc) ([Scaled Type] -> [Scaled Type]) -> [Scaled Type] -> [Scaled Type]
    forall a b. (a -> b) -> a -> b
    $
       (Scaled Type -> Scaled Type) -> [Scaled Type] -> [Scaled Type]
    forall a b. (a -> b) -> [a] -> [b]
    map ((Type -> Type) -> Scaled Type -> Scaled Type
    mapScaledType ([TyVar] -> [Type] -> Type -> Type
    HasDebugCallStack => [TyVar] -> [Type] -> Type -> Type
    substTyWith [TyVar]
    univ_tvs [Type]
    inst_tys)) (DataCon -> [Scaled Type]
    dataConRepArgTys DataCon
    dc)

    -- | Returns just the instantiated /value/ argument types of a 'DataCon',
    -- (excluding dictionary args)
    dataConInstOrigArgTys
            :: DataCon      -- Works for any DataCon
            -> [Type]       -- Includes existential tyvar args, but NOT
                            -- equality constraints or dicts
            -> [Scaled Type]
    -- For vanilla datacons, it's all quite straightforward
    -- But for the call in GHC.HsToCore.Match.Constructor, we really do want just
    -- the value args
    dataConInstOrigArgTys :: DataCon -> [Type] -> [Scaled Type]
    dataConInstOrigArgTys dc :: DataCon
    dc@(MkData {dcOrigArgTys :: DataCon -> [Scaled Type]
    dcOrigArgTys = [Scaled Type]
    arg_tys,
                                      dcUnivTyVars :: DataCon -> [TyVar]
    dcUnivTyVars = [TyVar]
    univ_tvs,
                                      dcExTyCoVars :: DataCon -> [TyVar]
    dcExTyCoVars = [TyVar]
    ex_tvs}) [Type]
    inst_tys
      = Bool -> SDoc -> [Scaled Type] -> [Scaled Type]
    forall a. HasCallStack => Bool -> SDoc -> a -> a
    assertPpr ([TyVar]
    tyvars [TyVar] -> [Type] -> Bool
    forall a b. [a] -> [b] -> Bool
    `equalLength` [Type]
    inst_tys)
                  (String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "dataConInstOrigArgTys" SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> DataCon -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr DataCon
    dc SDoc -> SDoc -> SDoc
    forall doc. IsDoc doc => doc -> doc -> doc
    $$ [TyVar] -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr [TyVar]
    tyvars SDoc -> SDoc -> SDoc
    forall doc. IsDoc doc => doc -> doc -> doc
    $$ [Type] -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr [Type]
    inst_tys) ([Scaled Type] -> [Scaled Type]) -> [Scaled Type] -> [Scaled Type]
    forall a b. (a -> b) -> a -> b
    $
        HasDebugCallStack => Subst -> [Scaled Type] -> [Scaled Type]
    Subst -> [Scaled Type] -> [Scaled Type]
    substScaledTys Subst
    subst [Scaled Type]
    arg_tys
      where
        tyvars :: [TyVar]
    tyvars = [TyVar]
    univ_tvs [TyVar] -> [TyVar] -> [TyVar]
    forall a. [a] -> [a] -> [a]
    ++ [TyVar]
    ex_tvs
        subst :: Subst
    subst  = [TyVar] -> [Type] -> Subst
    HasDebugCallStack => [TyVar] -> [Type] -> Subst
    zipTCvSubst [TyVar]
    tyvars [Type]
    inst_tys

    -- | Given a data constructor @dc@ with /n/ universally quantified type
    -- variables @a_{1}@, @a_{2}@, ..., @a_{n}@, and given a list of argument
    -- types @dc_args@ of length /m/ where /m/ <= /n/, then:
    --
    -- @
    -- dataConInstUnivs dc dc_args
    -- @
    --
    -- Will return:
    --
    -- @
    -- [dc_arg_{1}, dc_arg_{2}, ..., dc_arg_{m}, a_{m+1}, ..., a_{n}]
    -- @
    --
    -- That is, return the list of universal type variables with
    -- @a_{1}@, @a_{2}@, ..., @a_{m}@ instantiated with
    -- @dc_arg_{1}@, @dc_arg_{2}@, ..., @dc_arg_{m}@. It is possible for @m@ to
    -- be less than @n@, in which case the remaining @n - m@ elements will simply
    -- be universal type variables (with their kinds possibly instantiated).
    --
    -- Examples:
    --
    -- * Given the data constructor @D :: forall a b. Foo a b@ and
    --   @dc_args@ @[Int, Bool]@, then @dataConInstUnivs D dc_args@ will return
    --   @[Int, Bool]@.
    --
    -- * Given the data constructor @D :: forall a b. Foo a b@ and
    --   @dc_args@ @[Int]@, then @@dataConInstUnivs D dc_args@ will return
    --   @[Int, b]@.
    --
    -- * Given the data constructor @E :: forall k (a :: k). Bar k a@ and
    --   @dc_args@ @[Type]@, then @@dataConInstUnivs D dc_args@ will return
    --   @[Type, (a :: Type)]@.
    --
    -- This is primarily used in @GHC.Tc.Deriv.*@ in service of instantiating data
    -- constructors' field types.
    -- See @Note [Instantiating field types in stock deriving]@ for a notable
    -- example of this.
    dataConInstUnivs :: DataCon -> [Type] -> [Type]
    dataConInstUnivs :: DataCon -> [Type] -> [Type]
    dataConInstUnivs DataCon
    dc [Type]
    dc_args = [Type] -> [Type] -> [Type]
    forall a. [a] -> [a] -> [a]
    chkAppend [Type]
    dc_args ([Type] -> [Type]) -> [Type] -> [Type]
    forall a b. (a -> b) -> a -> b
    $ (TyVar -> Type) -> [TyVar] -> [Type]
    forall a b. (a -> b) -> [a] -> [b]
    map TyVar -> Type
    mkTyVarTy [TyVar]
    dc_args_suffix
      where
        ([TyVar]
    dc_univs_prefix, [TyVar]
    dc_univs_suffix)
                            = -- Assert that m <= n
                              Bool -> SDoc -> ([TyVar], [TyVar]) -> ([TyVar], [TyVar])
    forall a. HasCallStack => Bool -> SDoc -> a -> a
    assertPpr ([Type]
    dc_args [Type] -> [TyVar] -> Bool
    forall a b. [a] -> [b] -> Bool
    `leLength` DataCon -> [TyVar]
    dataConUnivTyVars DataCon
    dc)
                                        (String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "dataConInstUnivs"
                                          SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> [Type] -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr [Type]
    dc_args
                                          SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> [TyVar] -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr (DataCon -> [TyVar]
    dataConUnivTyVars DataCon
    dc)) (([TyVar], [TyVar]) -> ([TyVar], [TyVar]))
    -> ([TyVar], [TyVar]) -> ([TyVar], [TyVar])
    forall a b. (a -> b) -> a -> b
    $
                              [Type] -> [TyVar] -> ([TyVar], [TyVar])
    forall b a. [b] -> [a] -> ([a], [a])
    splitAtList [Type]
    dc_args ([TyVar] -> ([TyVar], [TyVar])) -> [TyVar] -> ([TyVar], [TyVar])
    forall a b. (a -> b) -> a -> b
    $ DataCon -> [TyVar]
    dataConUnivTyVars DataCon
    dc
        (Subst
    _, [TyVar]
    dc_args_suffix) = HasDebugCallStack => Subst -> [TyVar] -> (Subst, [TyVar])
    Subst -> [TyVar] -> (Subst, [TyVar])
    substTyVarBndrs Subst
    prefix_subst [TyVar]
    dc_univs_suffix
        prefix_subst :: Subst
    prefix_subst        = InScopeSet -> TvSubstEnv -> Subst
    mkTvSubst InScopeSet
    prefix_in_scope TvSubstEnv
    prefix_env
        prefix_in_scope :: InScopeSet
    prefix_in_scope     = VarSet -> InScopeSet
    mkInScopeSet (VarSet -> InScopeSet) -> VarSet -> InScopeSet
    forall a b. (a -> b) -> a -> b
    $ [Type] -> VarSet
    tyCoVarsOfTypes [Type]
    dc_args
        prefix_env :: TvSubstEnv
    prefix_env          = [TyVar] -> [Type] -> TvSubstEnv
    HasDebugCallStack => [TyVar] -> [Type] -> TvSubstEnv
    zipTyEnv [TyVar]
    dc_univs_prefix [Type]
    dc_args

    -- | Returns the argument types of the wrapper, excluding all dictionary arguments
    -- and without substituting for any type variables
    dataConOrigArgTys :: DataCon -> [Scaled Type]
    dataConOrigArgTys :: DataCon -> [Scaled Type]
    dataConOrigArgTys DataCon
    dc = DataCon -> [Scaled Type]
    dcOrigArgTys DataCon
    dc

    -- | Returns constraints in the wrapper type, other than those in the dataConEqSpec
    dataConOtherTheta :: DataCon -> ThetaType
    dataConOtherTheta :: DataCon -> [Type]
    dataConOtherTheta DataCon
    dc = DataCon -> [Type]
    dcOtherTheta DataCon
    dc

    -- | Returns the arg types of the worker, including *all* non-dependent
    -- evidence, after any flattening has been done and without substituting for
    -- any type variables
    dataConRepArgTys :: DataCon -> [Scaled Type]
    dataConRepArgTys :: DataCon -> [Scaled Type]
    dataConRepArgTys (MkData { dcRep :: DataCon -> DataConRep
    dcRep        = DataConRep
    rep
                             , dcEqSpec :: DataCon -> [EqSpec]
    dcEqSpec     = [EqSpec]
    eq_spec
                             , dcOtherTheta :: DataCon -> [Type]
    dcOtherTheta = [Type]
    theta
                             , dcOrigArgTys :: DataCon -> [Scaled Type]
    dcOrigArgTys = [Scaled Type]
    orig_arg_tys
                             , dcRepTyCon :: DataCon -> TyCon
    dcRepTyCon   = TyCon
    tc })
      = case DataConRep
    rep of
          DCR { dcr_arg_tys :: DataConRep -> [Scaled Type]
    dcr_arg_tys = [Scaled Type]
    arg_tys } -> [Scaled Type]
    arg_tys
          DataConRep
    NoDataConRep
            | TyCon -> Bool
    isTypeDataTyCon TyCon
    tc -> Bool -> [Scaled Type] -> [Scaled Type]
    forall a. HasCallStack => Bool -> a -> a
    assert ([Type] -> Bool
    forall a. [a] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null [Type]
    theta)   ([Scaled Type] -> [Scaled Type]) -> [Scaled Type] -> [Scaled Type]
    forall a b. (a -> b) -> a -> b
    $
                                    [Scaled Type]
    orig_arg_tys
              -- `type data` declarations can be GADTs (and hence have an eq_spec)
              -- but no wrapper.  They cannot have a theta.
              -- See Note [Type data declarations] in GHC.Rename.Module
              -- You might wonder why we ever call dataConRepArgTys for `type data`;
              -- I think it's because of the call in mkDataCon, which in turn feeds
              -- into dcRepArity, which in turn is used in mkDataConWorkId.
              -- c.f. #23022
            | Bool
    otherwise          -> Bool -> [Scaled Type] -> [Scaled Type]
    forall a. HasCallStack => Bool -> a -> a
    assert ([EqSpec] -> Bool
    forall a. [a] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null [EqSpec]
    eq_spec) ([Scaled Type] -> [Scaled Type]) -> [Scaled Type] -> [Scaled Type]
    forall a b. (a -> b) -> a -> b
    $
                                    (Type -> Scaled Type) -> [Type] -> [Scaled Type]
    forall a b. (a -> b) -> [a] -> [b]
    map Type -> Scaled Type
    forall a. a -> Scaled a
    unrestricted [Type]
    theta [Scaled Type] -> [Scaled Type] -> [Scaled Type]
    forall a. [a] -> [a] -> [a]
    ++ [Scaled Type]
    orig_arg_tys

    -- | The string @package:module.name@ identifying a constructor, which is attached
    -- to its info table and used by the GHCi debugger and the heap profiler
    dataConIdentity :: DataCon -> ByteString
    -- We want this string to be UTF-8, so we get the bytes directly from the FastStrings.
    dataConIdentity :: DataCon -> ByteString
    dataConIdentity DataCon
    dc = LazyByteString -> ByteString
    LBS.toStrict (LazyByteString -> ByteString) -> LazyByteString -> ByteString
    forall a b. (a -> b) -> a -> b
    $ Builder -> LazyByteString
    BSB.toLazyByteString (Builder -> LazyByteString) -> Builder -> LazyByteString
    forall a b. (a -> b) -> a -> b
    $ [Builder] -> Builder
    forall a. Monoid a => [a] -> a
    mconcat
       [ ShortByteString -> Builder
    BSB.shortByteString (ShortByteString -> Builder) -> ShortByteString -> Builder
    forall a b. (a -> b) -> a -> b
    $ FastString -> ShortByteString
    fastStringToShortByteString (FastString -> ShortByteString) -> FastString -> ShortByteString
    forall a b. (a -> b) -> a -> b
    $
           Unit -> FastString
    forall u. IsUnitId u => u -> FastString
    unitFS (Unit -> FastString) -> Unit -> FastString
    forall a b. (a -> b) -> a -> b
    $ GenModule Unit -> Unit
    forall unit. GenModule unit -> unit
    moduleUnit GenModule Unit
    mod
       , Int8 -> Builder
    BSB.int8 (Int8 -> Builder) -> Int8 -> Builder
    forall a b. (a -> b) -> a -> b
    $ Arity -> Int8
    forall a b. (Integral a, Num b) => a -> b
    fromIntegral (Char -> Arity
    ord Char
    ':')
       , ShortByteString -> Builder
    BSB.shortByteString (ShortByteString -> Builder) -> ShortByteString -> Builder
    forall a b. (a -> b) -> a -> b
    $ FastString -> ShortByteString
    fastStringToShortByteString (FastString -> ShortByteString) -> FastString -> ShortByteString
    forall a b. (a -> b) -> a -> b
    $
           ModuleName -> FastString
    moduleNameFS (ModuleName -> FastString) -> ModuleName -> FastString
    forall a b. (a -> b) -> a -> b
    $ GenModule Unit -> ModuleName
    forall unit. GenModule unit -> ModuleName
    moduleName GenModule Unit
    mod
       , Int8 -> Builder
    BSB.int8 (Int8 -> Builder) -> Int8 -> Builder
    forall a b. (a -> b) -> a -> b
    $ Arity -> Int8
    forall a b. (Integral a, Num b) => a -> b
    fromIntegral (Char -> Arity
    ord Char
    '.')
       , ShortByteString -> Builder
    BSB.shortByteString (ShortByteString -> Builder) -> ShortByteString -> Builder
    forall a b. (a -> b) -> a -> b
    $ FastString -> ShortByteString
    fastStringToShortByteString (FastString -> ShortByteString) -> FastString -> ShortByteString
    forall a b. (a -> b) -> a -> b
    $
           OccName -> FastString
    occNameFS (OccName -> FastString) -> OccName -> FastString
    forall a b. (a -> b) -> a -> b
    $ Name -> OccName
    nameOccName Name
    name
       ]
      where name :: Name
    name = DataCon -> Name
    dataConName DataCon
    dc
            mod :: GenModule Unit
    mod  = Bool -> GenModule Unit -> GenModule Unit
    forall a. HasCallStack => Bool -> a -> a
    assert (Name -> Bool
    isExternalName Name
    name) (GenModule Unit -> GenModule Unit)
    -> GenModule Unit -> GenModule Unit
    forall a b. (a -> b) -> a -> b
    $ HasDebugCallStack => Name -> GenModule Unit
    Name -> GenModule Unit
    nameModule Name
    name

    isTupleDataCon :: DataCon -> Bool
    isTupleDataCon :: DataCon -> Bool
    isTupleDataCon (MkData {dcRepTyCon :: DataCon -> TyCon
    dcRepTyCon = TyCon
    tc}) = TyCon -> Bool
    isTupleTyCon TyCon
    tc

    isBoxedTupleDataCon :: DataCon -> Bool
    isBoxedTupleDataCon :: DataCon -> Bool
    isBoxedTupleDataCon (MkData {dcRepTyCon :: DataCon -> TyCon
    dcRepTyCon = TyCon
    tc}) = TyCon -> Bool
    isBoxedTupleTyCon TyCon
    tc

    isUnboxedTupleDataCon :: DataCon -> Bool
    isUnboxedTupleDataCon :: DataCon -> Bool
    isUnboxedTupleDataCon (MkData {dcRepTyCon :: DataCon -> TyCon
    dcRepTyCon = TyCon
    tc}) = TyCon -> Bool
    isUnboxedTupleTyCon TyCon
    tc

    isUnboxedSumDataCon :: DataCon -> Bool
    isUnboxedSumDataCon :: DataCon -> Bool
    isUnboxedSumDataCon (MkData {dcRepTyCon :: DataCon -> TyCon
    dcRepTyCon = TyCon
    tc}) = TyCon -> Bool
    isUnboxedSumTyCon TyCon
    tc

    -- | Vanilla 'DataCon's are those that are nice boring Haskell 98 constructors
    isVanillaDataCon :: DataCon -> Bool
    isVanillaDataCon :: DataCon -> Bool
    isVanillaDataCon DataCon
    dc = DataCon -> Bool
    dcVanilla DataCon
    dc

    -- | Is this the 'DataCon' of a newtype?
    isNewDataCon :: DataCon -> Bool
    isNewDataCon :: DataCon -> Bool
    isNewDataCon DataCon
    dc = TyCon -> Bool
    isNewTyCon (DataCon -> TyCon
    dataConTyCon DataCon
    dc)

    -- | Is this data constructor in a "type data" declaration?
    -- See Note [Type data declarations] in GHC.Rename.Module.
    isTypeDataCon :: DataCon -> Bool
    isTypeDataCon :: DataCon -> Bool
    isTypeDataCon DataCon
    dc = TyCon -> Bool
    isTypeDataTyCon (DataCon -> TyCon
    dataConTyCon DataCon
    dc)

    isCovertGadtDataCon :: DataCon -> Bool
    -- See Note [isCovertGadtDataCon]
    isCovertGadtDataCon :: DataCon -> Bool
    isCovertGadtDataCon (MkData { dcUnivTyVars :: DataCon -> [TyVar]
    dcUnivTyVars  = [TyVar]
    univ_tvs
                                , dcEqSpec :: DataCon -> [EqSpec]
    dcEqSpec     = [EqSpec]
    eq_spec
                                , dcRepTyCon :: DataCon -> TyCon
    dcRepTyCon   = TyCon
    rep_tc })
      =  Bool -> Bool
    not ([EqSpec] -> Bool
    forall a. [a] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null [EqSpec]
    eq_spec)                -- There are some constraints
      Bool -> Bool -> Bool
    && Bool -> Bool
    not ((EqSpec -> Bool) -> [EqSpec] -> Bool
    forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
    any EqSpec -> Bool
    is_visible_spec [EqSpec]
    eq_spec) -- But none of them are visible
      where
        visible_univ_tvs :: [TyVar]  -- Visible arguments in result type
        visible_univ_tvs :: [TyVar]
    visible_univ_tvs
          = [ TyVar
    univ_tv | (TyVar
    univ_tv, TyConBinder
    tcb) <- [TyVar]
    univ_tvs [TyVar] -> [TyConBinder] -> [(TyVar, TyConBinder)]
    forall a b. [a] -> [b] -> [(a, b)]
    `zip` TyCon -> [TyConBinder]
    tyConBinders TyCon
    rep_tc
                      , TyConBinder -> Bool
    forall tv. VarBndr tv TyConBndrVis -> Bool
    isVisibleTyConBinder TyConBinder
    tcb ]

        is_visible_spec :: EqSpec -> Bool
        is_visible_spec :: EqSpec -> Bool
    is_visible_spec (EqSpec TyVar
    univ_tv Type
    ty)
           = TyVar
    univ_tv TyVar -> [TyVar] -> Bool
    forall a. Eq a => a -> [a] -> Bool
    forall (t :: * -> *) a. (Foldable t, Eq a) => a -> t a -> Bool
    `elem` [TyVar]
    visible_univ_tvs
             Bool -> Bool -> Bool
    && Bool -> Bool
    not (Type -> Bool
    isTyVarTy Type
    ty)  -- See Note [isCovertGadtDataCon] for
                                    -- an example where 'ty' is a tyvar

    {- Note [isCovertGadtDataCon]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    (isCovertGadtDataCon K) returns True if K is a GADT data constructor, but
    does not /look/ like it. Consider (#21447)
        type T :: TYPE r -> Type
        data T a where { MkT :: b -> T b }
    Here MkT doesn't look GADT-like, but it is. If we make the kind applications
    explicit we'd see:
        data T a where { MkT :: b -> T @LiftedRep b }

    The test for covert-ness is bit tricky, because we want to see if
      - dcEqSpec is non-empty
      - dcEqSpec does not constrain any of the /required/ (i.e. visible)
        arguments of the TyCon to a non-tyvar

    In the example above, the DataCon for MkT will have
        dcUnivTyVars: [(r::RuntimeRep), (a :: TYPE r)]
        dcExTyVars:   [(b :: Type)]
        dcEqSpec:     [(r, LiftedRep), (a, b)]
    Here
      * `r :: RuntimeRep` is constrained by dcEqSpec to LiftedRep
      * `a :: TYPE r` is constrained by dcEqSpec to `b :: Type`
    But the constraint on `a` is not visible to the user, so this counts
    as a covert GADT data con.  The declaration
         MkT :: forall (b :: Type). b -> T b
    looks entirely non-GADT-ish.

    Wrinkles:
    * The visibility or otherwise is a property of the /TyCon/ binders
    * The dcUnivTyVars may or may not be the same as the TyCon binders
    * So we have to zip them together.
    * For a data family the TyCon in question is the /representation/ TyCon
      hence dcRepTyCon
    -}

    -- | Should this DataCon be allowed in a type even without -XDataKinds?
    -- Currently, only Lifted & Unlifted
    specialPromotedDc :: DataCon -> Bool
    specialPromotedDc :: DataCon -> Bool
    specialPromotedDc = TyCon -> Bool
    isKindTyCon (TyCon -> Bool) -> (DataCon -> TyCon) -> DataCon -> Bool
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . DataCon -> TyCon
    dataConTyCon

    classDataCon :: Class -> DataCon
    classDataCon :: Class -> DataCon
    classDataCon Class
    clas = case TyCon -> [DataCon]
    tyConDataCons (Class -> TyCon
    classTyCon Class
    clas) of
                          (DataCon
    dict_constr:[DataCon]
    no_more) -> Bool -> DataCon -> DataCon
    forall a. HasCallStack => Bool -> a -> a
    assert ([DataCon] -> Bool
    forall a. [a] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null [DataCon]
    no_more) DataCon
    dict_constr
                          [] -> String -> DataCon
    forall a. HasCallStack => String -> a
    panic String
    "classDataCon"

    dataConCannotMatch :: [Type] -> DataCon -> Bool
    -- Returns True iff the data con *definitely cannot* match a
    --                  scrutinee of type (T tys)
    --                  where T is the dcRepTyCon for the data con
    dataConCannotMatch :: [Type] -> DataCon -> Bool
    dataConCannotMatch [Type]
    tys DataCon
    con
      -- See (U6) in Note [Implementing unsafeCoerce]
      -- in base:Unsafe.Coerce
      | DataCon -> Name
    dataConName DataCon
    con Name -> Name -> Bool
    forall a. Eq a => a -> a -> Bool
    == Name
    unsafeReflDataConName
                          = Bool
    False
      | [Type] -> Bool
    forall a. [a] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null [Type]
    inst_theta   = Bool
    False   -- Common
      | (Type -> Bool) -> [Type] -> Bool
    forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
    all Type -> Bool
    isTyVarTy [Type]
    tys = Bool
    False   -- Also common
      | Bool
    otherwise         = [(Type, Type)] -> Bool
    typesCantMatch ((Type -> [(Type, Type)]) -> [Type] -> [(Type, Type)]
    forall (t :: * -> *) a b. Foldable t => (a -> [b]) -> t a -> [b]
    concatMap Type -> [(Type, Type)]
    predEqs [Type]
    inst_theta)
      where
        ([TyVar]
    _, [Type]
    inst_theta, [Type]
    _) = DataCon -> [Type] -> ([TyVar], [Type], [Type])
    dataConInstSig DataCon
    con [Type]
    tys

        -- TODO: could gather equalities from superclasses too
        predEqs :: Type -> [(Type, Type)]
    predEqs Type
    pred = case Type -> Pred
    classifyPredType Type
    pred of
                         EqPred EqRel
    NomEq Type
    ty1 Type
    ty2         -> [(Type
    ty1, Type
    ty2)]
                         ClassPred Class
    eq [Type]
    args
                           | Class
    eq Class -> Unique -> Bool
    forall a. Uniquable a => a -> Unique -> Bool
    `hasKey` Unique
    eqTyConKey
                           , [Type
    _, Type
    ty1, Type
    ty2] <- [Type]
    args    -> [(Type
    ty1, Type
    ty2)]
                           | Class
    eq Class -> Unique -> Bool
    forall a. Uniquable a => a -> Unique -> Bool
    `hasKey` Unique
    heqTyConKey
                           , [Type
    _, Type
    _, Type
    ty1, Type
    ty2] <- [Type]
    args -> [(Type
    ty1, Type
    ty2)]
                         Pred
    _                            -> []

    -- | Were the type variables of the data con written in a different order
    -- than the regular order (universal tyvars followed by existential tyvars)?
    --
    -- This is not a cheap test, so we minimize its use in GHC as much as possible.
    -- Currently, its only call site in the GHC codebase is in 'mkDataConRep' in
    -- "MkId", and so 'dataConUserTyVarsNeedWrapper' is only called at most once
    -- during a data constructor's lifetime.

    dataConResRepTyArgs :: DataCon -> [Type]
    -- Returns the arguments of a GADT version of the /representation/ TyCon
    -- Thus   data instance T [(x,y)] z where
    --           MkT :: forall p q. Int -> T [(Int,p)] (Maybe q)
    -- The "GADT version of the representation type" is
    --        data R:T x y z where
    --           MkT :: forall p q. Int -> R:T Int p (Maybe q)
    -- so dataConResRepTyArgs for MkT returns [Int, p, Maybe q]
    -- This is almost the same as (subst eq_spec univ_tvs); but not quite,
    --   because eq_spec omits constraint-kinded equalities
    dataConResRepTyArgs :: DataCon -> [Type]
    dataConResRepTyArgs dc :: DataCon
    dc@(MkData { dcRepTyCon :: DataCon -> TyCon
    dcRepTyCon = TyCon
    rep_tc, dcOrigResTy :: DataCon -> Type
    dcOrigResTy = Type
    orig_res_ty })
      | Just (TyCon
    fam_tc, [Type]
    fam_args) <- TyCon -> Maybe (TyCon, [Type])
    tyConFamInst_maybe TyCon
    rep_tc
      = -- fvs(fam_args) = tyConTyVars rep_tc
        -- These tyvars are the domain of subst
        -- Fvs(range(subst)) = tvars of the datacon
        case  Type -> Type -> Maybe Subst
    tcMatchTy (TyCon -> [Type] -> Type
    mkTyConApp TyCon
    fam_tc [Type]
    fam_args) Type
    orig_res_ty of
           Just Subst
    subst -> (TyVar -> Type) -> [TyVar] -> [Type]
    forall a b. (a -> b) -> [a] -> [b]
    map (Subst -> TyVar -> Type
    substTyVar Subst
    subst) (TyCon -> [TyVar]
    tyConTyVars TyCon
    rep_tc)
           Maybe Subst
    Nothing    -> String -> SDoc -> [Type]
    forall a. HasCallStack => String -> SDoc -> a
    pprPanic String
    "datacOnResRepTyArgs" (SDoc -> [Type]) -> SDoc -> [Type]
    forall a b. (a -> b) -> a -> b
    $
                         [SDoc] -> SDoc
    forall doc. IsDoc doc => [doc] -> doc
    vcat [ DataCon -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr DataCon
    dc, TyCon -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr TyCon
    fam_tc SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> [Type] -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr [Type]
    fam_args
                              , Type -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Type
    orig_res_ty ]
      | Bool
    otherwise
      = HasDebugCallStack => Type -> [Type]
    Type -> [Type]
    tyConAppArgs Type
    orig_res_ty

    checkDataConTyVars :: DataCon -> Bool
    -- Check that the worker and wrapper have the same set of type variables
    -- See Note [DataCon user type variable binders]
    -- Also ensures that no user tyvar is in the eq_spec (the eq_spec should
    -- only relate fresh universals from (R2) of the note)
    checkDataConTyVars :: DataCon -> Bool
    checkDataConTyVars dc :: DataCon
    dc@(MkData { dcUnivTyVars :: DataCon -> [TyVar]
    dcUnivTyVars = [TyVar]
    univ_tvs
                                  , dcExTyCoVars :: DataCon -> [TyVar]
    dcExTyCoVars = [TyVar]
    ex_tvs
                                  , dcEqSpec :: DataCon -> [EqSpec]
    dcEqSpec = [EqSpec]
    eq_spec })
         -- use of sets here: (R1) from the Note
      = [TyVar] -> UnVarSet
    mkUnVarSet [TyVar]
    depleted_worker_vars UnVarSet -> UnVarSet -> Bool
    forall a. Eq a => a -> a -> Bool
    == [TyVar] -> UnVarSet
    mkUnVarSet [TyVar]
    wrapper_vars Bool -> Bool -> Bool
    &&
        (TyVar -> Bool) -> [TyVar] -> Bool
    forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
    all (Bool -> Bool
    not (Bool -> Bool) -> (TyVar -> Bool) -> TyVar -> Bool
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . TyVar -> Bool
    is_eq_spec_var) [TyVar]
    wrapper_vars
      where
        worker_vars :: [TyVar]
    worker_vars = [TyVar]
    univ_tvs [TyVar] -> [TyVar] -> [TyVar]
    forall a. [a] -> [a] -> [a]
    ++ [TyVar]
    ex_tvs
        eq_spec_tvs :: UnVarSet
    eq_spec_tvs = [TyVar] -> UnVarSet
    mkUnVarSet ((EqSpec -> TyVar) -> [EqSpec] -> [TyVar]
    forall a b. (a -> b) -> [a] -> [b]
    map EqSpec -> TyVar
    eqSpecTyVar [EqSpec]
    eq_spec)
        is_eq_spec_var :: TyVar -> Bool
    is_eq_spec_var = (TyVar -> UnVarSet -> Bool
    `elemUnVarSet` UnVarSet
    eq_spec_tvs)  -- (R2) from the Note
        depleted_worker_vars :: [TyVar]
    depleted_worker_vars = (TyVar -> Bool) -> [TyVar] -> [TyVar]
    forall a. (a -> Bool) -> [a] -> [a]
    filterOut TyVar -> Bool
    is_eq_spec_var [TyVar]
    worker_vars

        wrapper_vars :: [TyVar]
    wrapper_vars = DataCon -> [TyVar]
    dataConUserTyVars DataCon
    dc

    dataConUserTyVarsNeedWrapper :: DataCon -> Bool
    -- Check whether the worker and wapper have the same type variables
    -- in the same order. If not, we need a wrapper to swizzle them.
    -- See Note [DataCon user type variable binders], as well as
    -- Note [Data con wrappers and GADT syntax] for an explanation of what
    -- mkDataConRep is doing with this function.
    dataConUserTyVarsNeedWrapper :: DataCon -> Bool
    dataConUserTyVarsNeedWrapper dc :: DataCon
    dc@(MkData { dcUnivTyVars :: DataCon -> [TyVar]
    dcUnivTyVars = [TyVar]
    univ_tvs
                                            , dcExTyCoVars :: DataCon -> [TyVar]
    dcExTyCoVars = [TyVar]
    ex_tvs
                                            , dcEqSpec :: DataCon -> [EqSpec]
    dcEqSpec = [EqSpec]
    eq_spec })
      = Bool -> Bool -> Bool
    forall a. HasCallStack => Bool -> a -> a
    assert ([EqSpec] -> Bool
    forall a. [a] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null [EqSpec]
    eq_spec Bool -> Bool -> Bool
    || Bool
    answer)  -- all GADTs should say "yes" here
        Bool
    answer
      where
        answer :: Bool
    answer = ([TyVar]
    univ_tvs [TyVar] -> [TyVar] -> [TyVar]
    forall a. [a] -> [a] -> [a]
    ++ [TyVar]
    ex_tvs) [TyVar] -> [TyVar] -> Bool
    forall a. Eq a => a -> a -> Bool
    /= DataCon -> [TyVar]
    dataConUserTyVars DataCon
    dc
                  -- Worker tyvars         Wrapper tyvars

    {-
    %************************************************************************
    %*                                                                      *
            Promoting of data types to the kind level
    *                                                                      *
    ************************************************************************

    -}

    promoteDataCon :: DataCon -> TyCon
    promoteDataCon :: DataCon -> TyCon
    promoteDataCon (MkData { dcPromoted :: DataCon -> TyCon
    dcPromoted = TyCon
    tc }) = TyCon
    tc

    {-
    ************************************************************************
    *                                                                      *
    \subsection{Splitting products}
    *                                                                      *
    ************************************************************************
    -}

    -- | Extract the type constructor, type argument, data constructor and it's
    -- /representation/ argument types from a type if it is a product type.
    --
    -- Precisely, we return @Just@ for any data type that is all of:
    --
    --  * Concrete (i.e. constructors visible)
    --  * Single-constructor
    --  * ... which has no existentials
    --
    -- Whether the type is a @data@ type or a @newtype@.
    splitDataProductType_maybe
            :: Type                         -- ^ A product type, perhaps
            -> Maybe (TyCon,                -- The type constructor
                      [Type],               -- Type args of the tycon
                      DataCon,              -- The data constructor
                      [Scaled Type])        -- Its /representation/ arg types

            -- Rejecting existentials means we don't have to worry about
            -- freshening and substituting type variables
            -- (See "GHC.Type.Id.Make.dataConArgUnpack")

    splitDataProductType_maybe :: Type -> Maybe (TyCon, [Type], DataCon, [Scaled Type])
    splitDataProductType_maybe Type
    ty
      | Just (TyCon
    tycon, [Type]
    ty_args) <- HasDebugCallStack => Type -> Maybe (TyCon, [Type])
    Type -> Maybe (TyCon, [Type])
    splitTyConApp_maybe Type
    ty
      , Just DataCon
    con <- TyCon -> Maybe DataCon
    tyConSingleDataCon_maybe TyCon
    tycon
      , [TyVar] -> Bool
    forall a. [a] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null (DataCon -> [TyVar]
    dataConExTyCoVars DataCon
    con) -- no existentials! See above
      = (TyCon, [Type], DataCon, [Scaled Type])
    -> Maybe (TyCon, [Type], DataCon, [Scaled Type])
    forall a. a -> Maybe a
    Just (TyCon
    tycon, [Type]
    ty_args, DataCon
    con, DataCon -> [Type] -> [Scaled Type]
    dataConInstArgTys DataCon
    con [Type]
    ty_args)
      | Bool
    otherwise
      = Maybe (TyCon, [Type], DataCon, [Scaled Type])
    forall a. Maybe a
    Nothing