Newcomer looking for help with changes to kind system

Ben Gamari ben at smart-cactus.org
Wed Apr 7 15:29:17 UTC 2021


Shant Hairapetian <shanth2600 at gmail.com> writes:

> Hi Ben,
> Thanks for the reply
>
>> Incidentally, the collapse of LiftedRep and UnliftedRep will happen in
>> GHC 9.2 (turning into `BoxedRep :: Levity -> RuntimeRep`).
>
> Yes I believe this change was accidentally merged a few months ago then
> reverted? I will keep that in mind.
>
It was briefly accidentally merged, then reverted, then re-applied. The
final commit is 3e082f8ff5ea2f42c5e6430094683b26b5818fb8.

>> Can you provide a program that your patch rejects, as well as
>> the full error that is produced?
>
> My error is in stage 1 in the building of the ghc-bignum library. I have
> attached the full error as well as the patch itself.
>
See below.

> Thanks,
> Shant
>
>
>
> On Mon, Apr 5, 2021 at 7:41 PM Ben Gamari <ben at smart-cactus.org> wrote:
>
>> Shant Hairapetian <shanth2600 at gmail.com> writes:
>>
>> > Hello,
>> >
>> > I’m a master’s student working on implementing the changes outlined in
>> > “Kinds are Calling Conventions“ (
>> > https://www.microsoft.com/en-us/research/uploads/prod/2020/03/kacc.pdf).
>> I
>> > have been working directly with Paul Downen but have hit some roadblocks.
>> >
>> > To sum up the changes to the kind system, I am attempting to modify the
>> > “TYPE” type constructor to accept, rather than just a RuntimeRep, a
>> record
>> > type (called RuntimeInfo) comprised of a RuntimeRep and a CallingConv
>> > (calling convention). The calling convention has an “Eval” constructor
>> > which accepts a levity (effectively moving the levity information from
>> the
>> > representation to the calling convention. LiftedRep and UnliftedRep would
>> > also be collapsed into a single PtrRep constructor) and a “Call”
>> > constructor (denoting the arity of primitive, extensional functions,
>> > see: Making
>> > a Faster Curry with Extensional Types
>> > <
>> https://www.microsoft.com/en-us/research/uploads/prod/2019/07/arity-haskell-symposium-2019.pdf
>> >)
>> > which accepts a list of RuntimeRep’s. I have created and wired-in the new
>> > RuntimeInfo and CallingConv types in GHC.Builtin.Types, as well as the
>> > corresponding primitive types in GHC.Builtin.Types.Prim and have modified
>> > the “TYPE” constructor to accept a RuntimeInfo rather than a RuntimeRep.
>> >
>> Hi Shant,
>>
>> It would be helpful to have a bit more information on the nature of your
>> failure. Can you provide a program that your patch rejects, as well as
>> the full error that is produced?
>>
>> Incidentally, the collapse of LiftedRep and UnliftedRep will happen in
>> GHC 9.2 (turning into `BoxedRep :: Levity -> RuntimeRep`).
>>
>> Cheers,
>>
>> - Ben
>>
>>
>
> -- 
> Shant Hairapetian
>
>     libraries/ghc-bignum/src/GHC/Num/WordArray.hs:78:22: error:
>         • Couldn't match type: 'TupleRep ('[] @RuntimeRep)
>                          with: 'RInfo ('TupleRep ('[] @RuntimeRep)) 'GHC.Types.ConvEval
>           Expected: (# State# s, MutableWordArray# s #)
>             Actual: (# State# s, MutableByteArray# s #)
>         • In the expression: newByteArray# (wordsToBytes# sz) s
>           In an equation for ‘newWordArray#’:
>               newWordArray# sz s = newByteArray# (wordsToBytes# sz) s
>        |
>     78 | newWordArray# sz s = newByteArray# (wordsToBytes# sz) s
>        |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
>     libraries/ghc-bignum/src/GHC/Num/WordArray.hs:112:71: error:
>         • Couldn't match a lifted type with an unlifted type
>           When matching types
>             b0 :: TYPE ('RInfo 'LiftedRep 'GHC.Types.ConvEval)
>             WordArray# :: TYPE ('RInfo 'UnliftedRep 'GHC.Types.ConvEval)
>           Expected: (# () | WordArray# #)
>             Actual: (# () | b0 #)
>         • In the expression: a
>           In a case alternative: (# _, a #) -> a
>           In the expression: case runRW# io of { (# _, a #) -> a }
>         • Relevant bindings include
>             a :: (# () | b0 #)
>               (bound at libraries/ghc-bignum/src/GHC/Num/WordArray.hs:112:63)
>         |
>     112 | withNewWordArrayTrimedMaybe# sz act = case runRW# io of (# _, a #) -> a
>         |                                                                       ^
>
>     libraries/ghc-bignum/src/GHC/Num/WordArray.hs:117:40: error:
>         • Couldn't match kind ‘RuntimeInfo’ with ‘RuntimeRep’
>           When matching the kind of ‘'RInfo 'LiftedRep 'GHC.Types.ConvEval’
>         • In the expression: ()
>           In the expression: (# () | #)
>           In the expression: (# s, (# () | #) #)
>         |
>     117 |                (# s, 0# #) -> (# s, (# () | #) #)
>         |                                        ^^
>
>     libraries/ghc-bignum/src/GHC/Num/WordArray.hs:120:48: error:
>         • Couldn't match kind ‘RuntimeInfo’ with ‘RuntimeRep’
>           When matching kinds
>             'RInfo 'LiftedRep 'GHC.Types.ConvEval :: RuntimeInfo
>             'RInfo 'UnliftedRep 'GHC.Types.ConvEval :: RuntimeInfo
>         • In the expression: ba
>           In the expression: (# | ba #)
>           In the expression: (# s, (# | ba #) #)
>         |
>     120 |                      (# s, ba #) -> (# s, (# | ba #) #)
>         |                                                ^^
>
>     libraries/ghc-bignum/src/GHC/Num/WordArray.hs:431:31: error:
>         • Couldn't match type: 'TupleRep ('[] @RuntimeRep)
>                          with: 'RInfo ('TupleRep ('[] @RuntimeRep)) 'GHC.Types.ConvEval
>           Expected: (# State# s, Word# #)
>             Actual: (# State# s, Word# #)
>         • In the expression: readWordArray# mwa i s2
>           In a case alternative:
>               (# s2, sz #)
>                 | isTrue# (i >=# sz) -> (# s2, 0## #)
>                 | isTrue# (i <# 0#) -> (# s2, 0## #)
>                 | True -> readWordArray# mwa i s2
>           In the expression:
>             case mwaSize# mwa s of {
>               (# s2, sz #)
>                 | isTrue# (i >=# sz) -> (# s2, 0## #)
>                 | isTrue# (i <# 0#) -> (# s2, 0## #)
>                 | True -> readWordArray# mwa i s2 }
>         |
>     431 |       | True               -> readWordArray# mwa i s2
>         |                               ^^^^^^^^^^^^^^^^^^^^^^^
>
>     libraries/ghc-bignum/src/GHC/Num/WordArray.hs:434:12: error:
>         • Couldn't match type: 'TupleRep ('[] @RuntimeRep)
>                          with: 'RInfo ('TupleRep ('[] @RuntimeRep)) 'GHC.Types.ConvEval
>           Expected: MutableWordArray# s
>                     -> Int# -> State# s -> (# State# s, Word# #)
>             Actual: MutableByteArray# s
>                     -> Int# -> State# s -> (# State# s, Word# #)
>         • In the expression: readWordArray#
>           In an equation for ‘mwaRead#’: mwaRead# = readWordArray#
>         |
>     434 | mwaRead# = readWordArray#
> diff --git a/compiler/GHC/Builtin/Names.hs b/compiler/GHC/Builtin/Names.hs
> index cf0f72c50f..78c84147cb 100644
> --- a/compiler/GHC/Builtin/Names.hs
> +++ b/compiler/GHC/Builtin/Names.hs
> @@ -1949,6 +1949,15 @@ unrestrictedFunTyConKey = mkPreludeTyConUnique 193
>  multMulTyConKey :: Unique
>  multMulTyConKey = mkPreludeTyConUnique 194
>  
> +-- CallingConv
> +runtimeInfoTyConKey, runtimeInfoDataConKey, callingConvTyConKey,
> +   convEvalDataConKey, convCallDataConKey :: Unique
> +runtimeInfoTyConKey    = mkPreludeTyConUnique 195
> +runtimeInfoDataConKey  = mkPreludeDataConUnique 196
> +callingConvTyConKey    = mkPreludeTyConUnique 197
> +convEvalDataConKey     = mkPreludeDataConUnique 198
> +convCallDataConKey     = mkPreludeDataConUnique 199
> +
>  ---------------- Template Haskell -------------------
>  --      GHC.Builtin.Names.TH: USES TyConUniques 200-299
>  -----------------------------------------------------
> diff --git a/compiler/GHC/Builtin/Types.hs b/compiler/GHC/Builtin/Types.hs
> index d06bc4a12b..1bb6a263c6 100644
> --- a/compiler/GHC/Builtin/Types.hs
> +++ b/compiler/GHC/Builtin/Types.hs
> @@ -109,6 +109,7 @@ module GHC.Builtin.Types (
>  
>          -- * RuntimeRep and friends
>          runtimeRepTyCon, vecCountTyCon, vecElemTyCon,
> +        runtimeInfoTyCon, rInfo,
>  
>          runtimeRepTy, liftedRepTy, liftedRepDataCon, liftedRepDataConTyCon,
>  
> @@ -131,6 +132,9 @@ module GHC.Builtin.Types (
>  
>          doubleElemRepDataConTy,
>  
> +        runtimeInfoTy, runtimeInfoDataConTyCon, callingConvTy, liftedRepEvalTy,
> +        convEvalDataConTy,
> +
>          -- * Multiplicity and friends
>          multiplicityTyConName, oneDataConName, manyDataConName, multiplicityTy,
>          multiplicityTyCon, oneDataCon, manyDataCon, oneDataConTy, manyDataConTy,
> @@ -189,6 +193,7 @@ import GHC.Utils.Outputable
>  import GHC.Utils.Misc
>  import GHC.Utils.Panic
>  
> +import qualified GHC.Core.TyCo.Rep as TyCoRep (Type(TyConApp))
>  import qualified Data.ByteString.Char8 as BS
>  
>  import Data.List        ( elemIndex )
> @@ -266,6 +271,8 @@ wiredInTyCons = [ -- Units are not treated like other tuples, because they
>                  , multiplicityTyCon
>                  , naturalTyCon
>                  , integerTyCon
> +                , runtimeInfoTyCon
> +                , callingConvTyCon
>                  ]
>  
>  mkWiredInTyConName :: BuiltInSyntax -> Module -> FastString -> Unique -> TyCon -> Name
> @@ -689,7 +696,7 @@ constraintKindTyCon :: TyCon
>  constraintKindTyCon = pcTyCon constraintKindTyConName Nothing [] []
>  
>  liftedTypeKind, typeToTypeKind, constraintKind :: Kind
> -liftedTypeKind   = tYPE liftedRepTy
> +liftedTypeKind   = TyCoRep.TyConApp liftedTypeKindTyCon []
>  typeToTypeKind   = liftedTypeKind `mkVisFunTyMany` liftedTypeKind
>  constraintKind   = mkTyConApp constraintKindTyCon []
>  
> @@ -1027,7 +1034,7 @@ cTupleArr = listArray (0,mAX_CTUPLE_SIZE) [mk_ctuple i | i <- [0..mAX_CTUPLE_SIZ
>  -- [IntRep, LiftedRep])@
>  unboxedTupleSumKind :: TyCon -> [Type] -> Kind
>  unboxedTupleSumKind tc rr_tys
> -  = tYPE (mkTyConApp tc [mkPromotedListTy runtimeRepTy rr_tys])
> +  = tYPE $ mkTyConApp runtimeInfoDataConTyCon [(mkTyConApp tc [mkPromotedListTy runtimeRepTy rr_tys]), convEvalDataConTy]
>  
>  -- | Specialization of 'unboxedTupleSumKind' for tuples
>  unboxedTupleKind :: [Type] -> Kind
> @@ -1064,7 +1071,7 @@ mk_tuple Unboxed arity = (tycon, tuple_con)
>  
>      -- See Note [Unboxed tuple RuntimeRep vars] in GHC.Core.TyCon
>      -- Kind:  forall (k1:RuntimeRep) (k2:RuntimeRep). TYPE k1 -> TYPE k2 -> #
> -    tc_binders = mkTemplateTyConBinders (replicate arity runtimeRepTy)
> +    tc_binders = mkTemplateTyConBinders (replicate arity runtimeInfoTy)
>                                          (\ks -> map tYPE ks)
>  
>      tc_res_kind = unboxedTupleKind rr_tys
> @@ -1388,11 +1395,11 @@ unrestrictedFunTyCon :: TyCon
>  unrestrictedFunTyCon = buildSynTyCon unrestrictedFunTyConName [] arrowKind [] unrestrictedFunTy
>    where arrowKind = mkTyConKind binders liftedTypeKind
>          -- See also funTyCon
> -        binders = [ Bndr runtimeRep1TyVar (NamedTCB Inferred)
> -                  , Bndr runtimeRep2TyVar (NamedTCB Inferred)
> +        binders = [ Bndr runtimeInfo1TyVar (NamedTCB Inferred)
> +                  , Bndr runtimeInfo2TyVar (NamedTCB Inferred)
>                    ]
> -                  ++ mkTemplateAnonTyConBinders [ tYPE runtimeRep1Ty
> -                                                , tYPE runtimeRep2Ty
> +                  ++ mkTemplateAnonTyConBinders [ tYPE runtimeInfo1Ty
> +                                                , tYPE runtimeInfo2Ty
>                                                  ]
>  
>  unrestrictedFunTyConName :: Name
> @@ -1400,7 +1407,7 @@ unrestrictedFunTyConName = mkWiredInTyConName BuiltInSyntax gHC_TYPES (fsLit "->
>  
>  {- *********************************************************************
>  *                                                                      *
> -                Kinds and RuntimeRep
> +                Kinds, RuntimeRep and CallingConv
>  *                                                                      *
>  ********************************************************************* -}
>  
> @@ -1413,8 +1420,8 @@ runtimeRepTy = mkTyConTy runtimeRepTyCon
>  -- type Type = tYPE 'LiftedRep
>  liftedTypeKindTyCon :: TyCon
>  liftedTypeKindTyCon   = buildSynTyCon liftedTypeKindTyConName
> -                                       [] liftedTypeKind []
> -                                       (tYPE liftedRepTy)
> +                                       [] liftedTypeKind [] rhs
> +  where rhs = TyCoRep.TyConApp tYPETyCon [mkTyConApp  runtimeInfoDataConTyCon [liftedRepTy, convEvalDataConTy]]
>  
>  runtimeRepTyCon :: TyCon
>  runtimeRepTyCon = pcTyCon runtimeRepTyConName Nothing []
> @@ -1425,13 +1432,13 @@ vecRepDataCon :: DataCon
>  vecRepDataCon = pcSpecialDataCon vecRepDataConName [ mkTyConTy vecCountTyCon
>                                                     , mkTyConTy vecElemTyCon ]
>                                   runtimeRepTyCon
> -                                 (RuntimeRep prim_rep_fun)
> +                                 (RuntimeInfo prim_rep_fun)
>    where
>      -- See Note [Getting from RuntimeRep to PrimRep] in GHC.Types.RepType
>      prim_rep_fun [count, elem]
>        | VecCount n <- tyConRuntimeRepInfo (tyConAppTyCon count)
>        , VecElem  e <- tyConRuntimeRepInfo (tyConAppTyCon elem)
> -      = [VecRep n e]
> +      = [RInfo [(VecRep n e)] ConvEval]
>      prim_rep_fun args
>        = pprPanic "vecRepDataCon" (ppr args)
>  
> @@ -1440,11 +1447,11 @@ vecRepDataConTyCon = promoteDataCon vecRepDataCon
>  
>  tupleRepDataCon :: DataCon
>  tupleRepDataCon = pcSpecialDataCon tupleRepDataConName [ mkListTy runtimeRepTy ]
> -                                   runtimeRepTyCon (RuntimeRep prim_rep_fun)
> +                                   runtimeRepTyCon (RuntimeInfo prim_rep_fun)
>    where
>      -- See Note [Getting from RuntimeRep to PrimRep] in GHC.Types.RepType
>      prim_rep_fun [rr_ty_list]
> -      = concatMap (runtimeRepPrimRep doc) rr_tys
> +      = [RInfo (concatMap (runtimeRepPrimRep doc) rr_tys) ConvEval]
>        where
>          rr_tys = extractPromotedList rr_ty_list
>          doc    = text "tupleRepDataCon" <+> ppr rr_tys
> @@ -1456,11 +1463,11 @@ tupleRepDataConTyCon = promoteDataCon tupleRepDataCon
>  
>  sumRepDataCon :: DataCon
>  sumRepDataCon = pcSpecialDataCon sumRepDataConName [ mkListTy runtimeRepTy ]
> -                                 runtimeRepTyCon (RuntimeRep prim_rep_fun)
> +                                 runtimeRepTyCon (RuntimeInfo prim_rep_fun)
>    where
>      -- See Note [Getting from RuntimeRep to PrimRep] in GHC.Types.RepType
>      prim_rep_fun [rr_ty_list]
> -      = map slotPrimRep (ubxSumRepType prim_repss)
> +      = [RInfo (map slotPrimRep (ubxSumRepType prim_repss)) ConvEval]
>        where
>          rr_tys     = extractPromotedList rr_ty_list
>          doc        = text "sumRepDataCon" <+> ppr rr_tys
> @@ -1488,7 +1495,7 @@ runtimeRepSimpleDataCons@(liftedRepDataCon : _)
>      runtimeRepSimpleDataConNames
>    where
>      mk_runtime_rep_dc primrep name
> -      = pcSpecialDataCon name [] runtimeRepTyCon (RuntimeRep (\_ -> [primrep]))
> +      = pcSpecialDataCon name [] runtimeRepTyCon (RuntimeInfo (\_ -> [RInfo [primrep] ConvEval]))
>  
>  -- See Note [Wiring in RuntimeRep]
>  liftedRepDataConTy, unliftedRepDataConTy,
> @@ -1558,6 +1565,79 @@ liftedRepDataConTyCon = promoteDataCon liftedRepDataCon
>  liftedRepTy :: Type
>  liftedRepTy = liftedRepDataConTy
>  
> +-- The type ('BoxedRep 'UnliftedRep)
> +unliftedRepTy :: Type
> +unliftedRepTy = unliftedRepDataConTy
> +
> +unliftedRepEvalTy :: Type
> +unliftedRepEvalTy = mkTyConApp runtimeInfoDataConTyCon [unliftedRepTy, convEvalDataConTy]
> +
> +liftedRepEvalTy :: Type
> +liftedRepEvalTy = mkTyConApp runtimeInfoDataConTyCon [liftedRepTy, convEvalDataConTy]
> +
> +callingConvTyConName, convEvalDataConName, convCallDataConName :: Name
> +callingConvTyConName = mkWiredInTyConName UserSyntax gHC_TYPES (fsLit "CallingConv") callingConvTyConKey callingConvTyCon
> +convEvalDataConName  = mkWiredInDataConName UserSyntax gHC_TYPES (fsLit "ConvEval") convEvalDataConKey convEvalDataCon
> +-- convCallDataConName  = mkWiredInDataConName UserSyntax gHC_TYPES (fsLit "ConvCall") convCallDataConKey convCallDataCon
> +convCallDataConName = undefined
> +
> +convEvalDataCon = pcSpecialDataCon convEvalDataConName [] callingConvTyCon (CallingConvInfo $ \_ -> [ConvEval])
> +
> +convEvalDataConTyCon :: TyCon
> +convEvalDataConTyCon = promoteDataCon convEvalDataCon
> +
> +convEvalDataConTy :: Type
> +convEvalDataConTy = mkTyConTy convEvalDataConTyCon
> +
> +
> +callingConvTyCon :: TyCon
> +callingConvTyCon = pcTyCon callingConvTyConName Nothing []
> +    [convEvalDataCon]
> +
> +callingConvTy :: Type
> +callingConvTy = mkTyConTy callingConvTyCon 
> +
> +{- *********************************************************************
> +*                                                                      *
> +     RuntimeInfo Types
> +*                                                                      *
> +********************************************************************* -}
> +
> +runtimeInfoTyConName, runtimeInfoDataConName :: Name
> +runtimeInfoTyConName = mkWiredInTyConName UserSyntax gHC_TYPES (fsLit "RuntimeInfo") runtimeInfoTyConKey runtimeInfoTyCon
> +runtimeInfoDataConName = mkWiredInDataConName UserSyntax gHC_TYPES (fsLit "RInfo") runtimeInfoDataConKey runtimeInfoDataCon
> +
> +runtimeInfoTyCon :: TyCon
> +runtimeInfoTyCon = pcTyCon runtimeInfoTyConName Nothing []
> +    [runtimeInfoDataCon]
> +
> +runtimeInfoDataCon :: DataCon
> +runtimeInfoDataCon = pcSpecialDataCon runtimeInfoDataConName [ runtimeRepTy
> +                                                   , mkTyConTy callingConvTyCon ]
> +                                 runtimeInfoTyCon
> +                                 (RuntimeInfo prim_info_fun)
> +  where
> +    -- See Note [Getting from RuntimeRep to PrimRep] in GHC.Types.RepType
> +    prim_info_fun tys@[rep, conv]
> +      = pprPanic "here runtimeInfoDataCon" (ppr tys)
> +        -- [RInfo (runtimeRepPrimRep doc rep)  ConvEval]
> +        where doc = text "runtimeInfoDataCon" <+> ppr tys
> +    prim_info_fun args
> +      = pprPanic "runtimeInfoDataCon" (ppr args)
> +
> +runtimeInfoDataConTyCon :: TyCon
> +runtimeInfoDataConTyCon = promoteDataCon runtimeInfoDataCon
> +
> +runtimeInfoDataConTy :: Type
> +runtimeInfoDataConTy = mkTyConTy runtimeInfoDataConTyCon
> +
> +runtimeInfoTy :: Type
> +runtimeInfoTy = mkTyConTy runtimeInfoTyCon
> +
> +rInfo :: Type -> Type -> Type
> +rInfo rep conv = TyCoRep.TyConApp runtimeInfoTyCon [rep, conv]
> +
> +
>  {- *********************************************************************
>  *                                                                      *
>       The boxed primitive types: Char, Int, etc
> diff --git a/compiler/GHC/Builtin/Types.hs-boot b/compiler/GHC/Builtin/Types.hs-boot
> index 000df212c3..fc82f9d7b9 100644
> --- a/compiler/GHC/Builtin/Types.hs-boot
> +++ b/compiler/GHC/Builtin/Types.hs-boot
> @@ -23,6 +23,13 @@ constraintKind :: Kind
>  runtimeRepTyCon, vecCountTyCon, vecElemTyCon :: TyCon
>  runtimeRepTy :: Type
>  
> +
> +runtimeInfoTy, callingConvTy, convEvalDataConTy :: Type
> +
> +runtimeInfoTyCon, runtimeInfoDataConTyCon :: TyCon
> +
> +rInfo :: Type -> Type -> Type
> +
>  liftedRepDataConTyCon, vecRepDataConTyCon, tupleRepDataConTyCon :: TyCon
>  
>  liftedRepDataConTy, unliftedRepDataConTy,
> diff --git a/compiler/GHC/Builtin/Types/Prim.hs b/compiler/GHC/Builtin/Types/Prim.hs
> index fc74596e45..5fb750649c 100644
> --- a/compiler/GHC/Builtin/Types/Prim.hs
> +++ b/compiler/GHC/Builtin/Types/Prim.hs
> @@ -24,6 +24,7 @@ module GHC.Builtin.Types.Prim(
>          alphaTyVarsUnliftedRep, alphaTyVarUnliftedRep,
>          alphaTysUnliftedRep, alphaTyUnliftedRep,
>          runtimeRep1TyVar, runtimeRep2TyVar, runtimeRep1Ty, runtimeRep2Ty,
> +        runtimeInfo1TyVar, runtimeInfo2TyVar, runtimeInfo1Ty, runtimeInfo2Ty,
>          openAlphaTy, openBetaTy, openAlphaTyVar, openBetaTyVar,
>  
>          multiplicityTyVar,
> @@ -97,6 +98,7 @@ import GHC.Prelude
>  
>  import {-# SOURCE #-} GHC.Builtin.Types
>    ( runtimeRepTy, unboxedTupleKind, liftedTypeKind
> +  , runtimeInfoTy, runtimeInfoDataConTyCon, convEvalDataConTy
>    , vecRepDataConTyCon, tupleRepDataConTyCon
>    , liftedRepDataConTy, unliftedRepDataConTy
>    , intRepDataConTy
> @@ -382,11 +384,19 @@ runtimeRep1Ty, runtimeRep2Ty :: Type
>  runtimeRep1Ty = mkTyVarTy runtimeRep1TyVar
>  runtimeRep2Ty = mkTyVarTy runtimeRep2TyVar
>  
> +runtimeInfo1TyVar, runtimeInfo2TyVar :: TyVar
> +(runtimeInfo1TyVar : runtimeInfo2TyVar : _)
> +  = drop 16 (mkTemplateTyVars (repeat runtimeInfoTy))  -- selects 'q','r'  
> +
> +runtimeInfo1Ty, runtimeInfo2Ty :: Type
> +runtimeInfo1Ty = mkTyVarTy runtimeInfo1TyVar
> +runtimeInfo2Ty = mkTyVarTy runtimeInfo2TyVar
> +
>  openAlphaTyVar, openBetaTyVar :: TyVar
>  -- alpha :: TYPE r1
>  -- beta  :: TYPE r2
>  [openAlphaTyVar,openBetaTyVar]
> -  = mkTemplateTyVars [tYPE runtimeRep1Ty, tYPE runtimeRep2Ty]
> +  = mkTemplateTyVars [tYPE runtimeInfo1Ty, tYPE runtimeInfo2Ty]
>  
>  openAlphaTy, openBetaTy :: Type
>  openAlphaTy = mkTyVarTy openAlphaTyVar
> @@ -432,10 +442,10 @@ funTyCon = mkFunTyCon funTyConName tc_bndrs tc_rep_nm
>    where
>      -- See also unrestrictedFunTyCon
>      tc_bndrs = [ mkNamedTyConBinder Required multiplicityTyVar
> -               , mkNamedTyConBinder Inferred runtimeRep1TyVar
> -               , mkNamedTyConBinder Inferred runtimeRep2TyVar ]
> -               ++ mkTemplateAnonTyConBinders [ tYPE runtimeRep1Ty
> -                                             , tYPE runtimeRep2Ty
> +               , mkNamedTyConBinder Inferred runtimeInfo1TyVar
> +               , mkNamedTyConBinder Inferred runtimeInfo2TyVar ]
> +               ++ mkTemplateAnonTyConBinders [ tYPE runtimeInfo1Ty
> +                                             , tYPE runtimeInfo2Ty
>                                               ]
>      tc_rep_nm = mkPrelTyConRepName funTyConName
>  
> @@ -529,7 +539,7 @@ tYPETyCon :: TyCon
>  tYPETyConName :: Name
>  
>  tYPETyCon = mkKindTyCon tYPETyConName
> -                        (mkTemplateAnonTyConBinders [runtimeRepTy])
> +                        (mkTemplateAnonTyConBinders [runtimeInfoTy])
>                          liftedTypeKind
>                          [Nominal]
>                          (mkPrelTyConRepName tYPETyConName)
> @@ -574,7 +584,7 @@ pcPrimTyCon name roles rep
>    = mkPrimTyCon name binders result_kind roles
>    where
>      binders     = mkTemplateAnonTyConBinders (map (const liftedTypeKind) roles)
> -    result_kind = tYPE (primRepToRuntimeRep rep)
> +    result_kind = tYPE $ TyConApp runtimeInfoDataConTyCon [(primRepToRuntimeRep rep), convEvalDataConTy]
>  
>  -- | Convert a 'PrimRep' to a 'Type' of kind RuntimeRep
>  -- Defined here to avoid (more) module loops
> diff --git a/compiler/GHC/Core/Make.hs b/compiler/GHC/Core/Make.hs
> index 6d6dd38b29..da285a6455 100644
> --- a/compiler/GHC/Core/Make.hs
> +++ b/compiler/GHC/Core/Make.hs
> @@ -913,7 +913,7 @@ mkRuntimeErrorId name
>  runtimeErrorTy :: Type
>  -- forall (rr :: RuntimeRep) (a :: rr). Addr# -> a
>  --   See Note [Error and friends have an "open-tyvar" forall]
> -runtimeErrorTy = mkSpecForAllTys [runtimeRep1TyVar, openAlphaTyVar]
> +runtimeErrorTy = mkSpecForAllTys [runtimeInfo1TyVar, openAlphaTyVar]
>                                   (mkVisFunTyMany addrPrimTy openAlphaTy)
>  
>  {- Note [Error and friends have an "open-tyvar" forall]
> diff --git a/compiler/GHC/Core/TyCon.hs b/compiler/GHC/Core/TyCon.hs
> index 198b66959b..5c59548ebf 100644
> --- a/compiler/GHC/Core/TyCon.hs
> +++ b/compiler/GHC/Core/TyCon.hs
> @@ -120,6 +120,7 @@ module GHC.Core.TyCon(
>  
>          -- * Primitive representations of Types
>          PrimRep(..), PrimElemRep(..),
> +        PrimConv (..), PrimInfo (..),
>          isVoidRep, isGcPtrRep,
>          primRepSizeB,
>          primElemRepSizeB,
> @@ -172,6 +173,10 @@ import GHC.Unit.Module
>  
>  import qualified Data.Data as Data
>  
> +import {-# SOURCE #-} GHC.Core.Type (splitTyConApp_maybe)
> +-- import {-# SOURCE #-} GHC.Builtin.Types.Prim (mutableByteArrayPrimTyConKey)
> +import GHC.Builtin.Names
> +
>  {-
>  -----------------------------------------------
>          Notes about type families
> @@ -1073,6 +1078,8 @@ data RuntimeRepInfo
>        -- be the list of arguments to the promoted datacon.
>    | VecCount Int         -- ^ A constructor of @VecCount@
>    | VecElem PrimElemRep  -- ^ A constructor of @VecElem@
> +  | RuntimeInfo ([Type] -> [PrimInfo])
> +  | CallingConvInfo ([Type] -> [PrimConv])
>  
>  -- | Extract those 'DataCon's that we are able to learn about.  Note
>  -- that visibility in this sense does not correspond to visibility in
> @@ -1550,6 +1557,26 @@ primRepIsFloat  DoubleRep    = Just True
>  primRepIsFloat  (VecRep _ _) = Nothing
>  primRepIsFloat  _            = Just False
>  
> +{-
> +************************************************************************
> +*                                                                      *
> +                             PrimConv
> +*                                                                      *
> +************************************************************************
> +
> +Note [PrimConv]
> +
> +A type for representing the calling convention of a type. Either the arity
> +for extensional functions or the levity for data terms.
> +-}
> +
> +data PrimConv =  
> +    ConvEval 
> +  -- | ConvCall [PrimRep] 
> +  deriving (Show)
> +
> +data PrimInfo = RInfo {reps :: [PrimRep], conv :: PrimConv}  
> +
>  
>  {-
>  ************************************************************************
> @@ -2326,11 +2353,17 @@ expandSynTyCon_maybe
>  
>  -- ^ Expand a type synonym application, if any
>  expandSynTyCon_maybe tc tys
> +  -- | SynonymTyCon { tyConTyVars = tvs, synTcRhs = rhs, tyConArity = arity } <- tc
> +  -- , Just (tc' , _) <- splitTyConApp_maybe rhs
> +  -- , tc' `hasKey` (mutableByteArrayPrimTyConKey)
> +  -- = pprPanic "here" (ppr tc)
> +  
>    | SynonymTyCon { tyConTyVars = tvs, synTcRhs = rhs, tyConArity = arity } <- tc
>    = case tys `listLengthCmp` arity of
>          GT -> Just (tvs `zip` tys, rhs, drop arity tys)
>          EQ -> Just (tvs `zip` tys, rhs, [])
>          LT -> Nothing
> +  
>    | otherwise
>    = Nothing
>  
> diff --git a/compiler/GHC/Core/Type.hs b/compiler/GHC/Core/Type.hs
> index 3164e2626b..5f3ab18925 100644
> --- a/compiler/GHC/Core/Type.hs
> +++ b/compiler/GHC/Core/Type.hs
> @@ -68,6 +68,7 @@ module GHC.Core.Type (
>          isPredTy,
>  
>          getRuntimeRep_maybe, kindRep_maybe, kindRep,
> +        getRuntimeInfo, getRuntimeInfo_maybe, kindInfo,
>  
>          mkCastTy, mkCoercionTy, splitCastTy_maybe,
>  
> @@ -125,6 +126,7 @@ module GHC.Core.Type (
>          isAlgType, isDataFamilyAppType,
>          isPrimitiveType, isStrictType,
>          isRuntimeRepTy, isRuntimeRepVar, isRuntimeRepKindedTy,
> +        isRuntimeInfoTy, isRuntimeInfoVar,
>          dropRuntimeRepArgs,
>          getRuntimeRep,
>  
> @@ -554,6 +556,11 @@ kindRep k = case kindRep_maybe k of
>                Just r  -> r
>                Nothing -> pprPanic "kindRep" (ppr k)
>  
> +kindInfo :: HasDebugCallStack => Kind -> Type
> +kindInfo k = case kindInfo_maybe k of
> +              Just r  -> r
> +              Nothing -> pprPanic "kindInfo" (ppr k)              
> +
>  -- | Given a kind (TYPE rr), extract its RuntimeRep classifier rr.
>  -- For example, @kindRep_maybe * = Just LiftedRep@
>  -- Returns 'Nothing' if the kind is not of form (TYPE rr)
> @@ -561,18 +568,33 @@ kindRep k = case kindRep_maybe k of
>  kindRep_maybe :: HasDebugCallStack => Kind -> Maybe Type
>  kindRep_maybe kind
>    | TyConApp tc [arg] <- coreFullView kind
> -  , tc `hasKey` tYPETyConKey    = Just arg
> -  | otherwise                   = Nothing
> +  , tc `hasKey` tYPETyConKey
> +  , TyConApp rinfo [rep, conv] <- coreFullView arg
> +  , rinfo `hasKey` runtimeInfoDataConKey    = Just rep
> +  | TyConApp tc [arg] <- coreFullView kind
> +  , tc `hasKey` tYPETyConKey                = Just arg
> +  | otherwise                               = Nothing
> +
> +kindInfo_maybe :: HasDebugCallStack => Kind -> Maybe Type
> +kindInfo_maybe kind
> +  | TyConApp tc [arg] <- coreFullView kind
> +  , tc `hasKey` tYPETyConKey
> +  , TyConApp rinfo [rep, conv] <- coreFullView arg
> +  , rinfo `hasKey` runtimeInfoDataConKey    = Just arg
> +  | TyConApp tc [arg] <- coreFullView kind
> +  , tc `hasKey` tYPETyConKey                = Just arg
> +  | otherwise                               = Nothing
>  
>  -- | This version considers Constraint to be the same as *. Returns True
>  -- if the argument is equivalent to Type/Constraint and False otherwise.
>  -- See Note [Kind Constraint and kind Type]
>  isLiftedTypeKind :: Kind -> Bool
>  isLiftedTypeKind kind
> -  = case kindRep_maybe kind of
> -      Just rep -> isLiftedRuntimeRep rep
> +  = case kindInfo_maybe kind of
> +      Just rinfo -> isLiftedRuntimeInfo rinfo
>        Nothing  -> False
>  
> +
>  pickyIsLiftedTypeKind :: Kind -> Bool
>  -- Checks whether the kind is literally
>  --      TYPE LiftedRep
> @@ -599,13 +621,23 @@ isLiftedRuntimeRep rep
>    , rr_tc `hasKey` liftedRepDataConKey = ASSERT( null args ) True
>    | otherwise                          = False
>  
> +isLiftedRuntimeInfo :: Type -> Bool
> +-- isLiftedRuntimeRep is true of LiftedRep :: RuntimeRep
> +-- False of type variables (a :: RuntimeRep)
> +--   and of other reps e.g. (IntRep :: RuntimeRep)
> +isLiftedRuntimeInfo rep
> +  | TyConApp rr_tc [rep,conv] <- coreFullView rep
> +  , rr_tc `hasKey` runtimeInfoDataConKey = isLiftedRuntimeRep rep
> +  | otherwise
> +  = False
> +
>  -- | Returns True if the kind classifies unlifted types and False otherwise.
>  -- Note that this returns False for levity-polymorphic kinds, which may
>  -- be specialized to a kind that classifies unlifted types.
>  isUnliftedTypeKind :: Kind -> Bool
>  isUnliftedTypeKind kind
> -  = case kindRep_maybe kind of
> -      Just rep -> isUnliftedRuntimeRep rep
> +  = case kindInfo_maybe kind of
> +      Just rep -> isUnliftedRuntimeInfo rep
>        Nothing  -> False
>  
>  isUnliftedRuntimeRep :: Type -> Bool
> @@ -622,6 +654,17 @@ isUnliftedRuntimeRep rep
>    | otherwise {- Variables, applications -}
>    = False
>  
> +isUnliftedRuntimeInfo rep
> +  | TyConApp rinfo [rep, conv] <- coreFullView rep   -- NB: args might be non-empty
> +  , rinfo `hasKey` runtimeInfoDataConKey
> +  = isUnliftedRuntimeRep rep
> +        -- Avoid searching all the unlifted RuntimeRep type cons
> +        -- In the RuntimeRep data type, only LiftedRep is lifted
> +        -- But be careful of type families (F tys) :: RuntimeRep
> +  | otherwise {- Variables, applications -}
> +  = False
> +
> +
>  -- | Is this the type 'RuntimeRep'?
>  isRuntimeRepTy :: Type -> Bool
>  isRuntimeRepTy ty
> @@ -644,6 +687,17 @@ isMultiplicityTy ty
>  isMultiplicityVar :: TyVar -> Bool
>  isMultiplicityVar = isMultiplicityTy . tyVarKind
>  
> +-- | Is this the type 'RuntimeInfo'?
> +isRuntimeInfoTy :: Type -> Bool
> +isRuntimeInfoTy ty
> +  | TyConApp tc args <- coreFullView ty
> +  , tc `hasKey` runtimeInfoTyConKey = True
> +  | otherwise = False
> +
> +-- | Is a tyvar of type 'RuntimeInfo'?
> +isRuntimeInfoVar :: TyVar -> Bool
> +isRuntimeInfoVar = isRuntimeInfoTy . tyVarKind
> +
>  {- *********************************************************************
>  *                                                                      *
>                 mapType
> @@ -927,8 +981,8 @@ repSplitAppTy_maybe :: HasDebugCallStack => Type -> Maybe (Type,Type)
>  repSplitAppTy_maybe (FunTy _ w ty1 ty2)
>    = Just (TyConApp funTyCon [w, rep1, rep2, ty1], ty2)
>    where
> -    rep1 = getRuntimeRep ty1
> -    rep2 = getRuntimeRep ty2
> +    rep1 = getRuntimeInfo ty1
> +    rep2 = getRuntimeInfo ty2
>  
>  repSplitAppTy_maybe (AppTy ty1 ty2)
>    = Just (ty1, ty2)
> @@ -2049,6 +2103,10 @@ getRuntimeRep_maybe :: HasDebugCallStack
>                      => Type -> Maybe Type
>  getRuntimeRep_maybe = kindRep_maybe . typeKind
>  
> +getRuntimeInfo_maybe :: HasDebugCallStack
> +                    => Type -> Maybe Type
> +getRuntimeInfo_maybe = kindInfo_maybe . typeKind
> +
>  -- | Extract the RuntimeRep classifier of a type. For instance,
>  -- @getRuntimeRep_maybe Int = LiftedRep at . Panics if this is not possible.
>  getRuntimeRep :: HasDebugCallStack => Type -> Type
> @@ -2057,6 +2115,12 @@ getRuntimeRep ty
>        Just r  -> r
>        Nothing -> pprPanic "getRuntimeRep" (ppr ty <+> dcolon <+> ppr (typeKind ty))
>  
> +getRuntimeInfo :: HasDebugCallStack => Type -> Type
> +getRuntimeInfo ty
> +  = case getRuntimeInfo_maybe ty of
> +      Just r  -> r
> +      Nothing -> pprPanic "getRuntimeInfo" (ppr ty <+> dcolon <+> ppr (typeKind ty))      
> +
>  isUnboxedTupleType :: Type -> Bool
>  isUnboxedTupleType ty
>    = tyConAppTyCon (getRuntimeRep ty) `hasKey` tupleRepDataConKey
> @@ -2584,7 +2648,9 @@ tcIsLiftedTypeKind :: Kind -> Bool
>  tcIsLiftedTypeKind ty
>    | Just (tc, [arg]) <- tcSplitTyConApp_maybe ty    -- Note: tcSplit here
>    , tc `hasKey` tYPETyConKey
> -  = isLiftedRuntimeRep arg
> +  , Just (rinfo, [rep, conv]) <- tcSplitTyConApp_maybe arg
> +  , rinfo `hasKey` runtimeInfoDataConKey
> +  = isLiftedRuntimeRep rep
>    | otherwise
>    = False
>  
> diff --git a/compiler/GHC/HsToCore.hs b/compiler/GHC/HsToCore.hs
> index 9cf33aa02a..3522ad6fab 100644
> --- a/compiler/GHC/HsToCore.hs
> +++ b/compiler/GHC/HsToCore.hs
> @@ -714,7 +714,7 @@ mkUnsafeCoercePrimPair _old_id old_expr
>  
>         ; let [unsafe_refl_data_con] = tyConDataCons unsafe_equality_tc
>  
> -             rhs = mkLams [ runtimeRep1TyVar, runtimeRep2TyVar
> +             rhs = mkLams [ runtimeInfo1TyVar, runtimeInfo2TyVar
>                            , openAlphaTyVar, openBetaTyVar
>                            , x ] $
>                     mkSingleAltCase scrut1
> @@ -742,10 +742,10 @@ mkUnsafeCoercePrimPair _old_id old_expr
>               -- NB: UnsafeRefl :: (b ~# a) -> UnsafeEquality a b, so we have to
>               -- carefully swap the arguments above
>  
> -             (scrut1, scrut1_ty, rr_cv_ty) = unsafe_equality runtimeRepTy
> -                                                             runtimeRep1Ty
> -                                                             runtimeRep2Ty
> -             (scrut2, scrut2_ty, ab_cv_ty) = unsafe_equality (tYPE runtimeRep2Ty)
> +             (scrut1, scrut1_ty, rr_cv_ty) = unsafe_equality runtimeInfoTy
> +                                                             runtimeInfo1Ty
> +                                                             runtimeInfo2Ty
> +             (scrut2, scrut2_ty, ab_cv_ty) = unsafe_equality (tYPE runtimeInfo2Ty)
>                                                               (openAlphaTy `mkCastTy` alpha_co)
>                                                               openBetaTy
>  
> @@ -761,7 +761,7 @@ mkUnsafeCoercePrimPair _old_id old_expr
>               info = noCafIdInfo `setInlinePragInfo` alwaysInlinePragma
>                                  `setUnfoldingInfo` mkCompulsoryUnfolding' rhs
>  
> -             ty = mkSpecForAllTys [ runtimeRep1TyVar, runtimeRep2TyVar
> +             ty = mkSpecForAllTys [ runtimeInfo1TyVar, runtimeInfo2TyVar
>                                    , openAlphaTyVar, openBetaTyVar ] $
>                    mkVisFunTyMany openAlphaTy openBetaTy
>  
> diff --git a/compiler/GHC/HsToCore/Utils.hs b/compiler/GHC/HsToCore/Utils.hs
> index 01085b3270..688d227a6e 100644
> --- a/compiler/GHC/HsToCore/Utils.hs
> +++ b/compiler/GHC/HsToCore/Utils.hs
> @@ -407,7 +407,7 @@ mkErrorAppDs err_id ty msg = do
>          full_msg = showSDoc dflags (hcat [ppr src_loc, vbar, msg])
>          core_msg = Lit (mkLitString full_msg)
>          -- mkLitString returns a result of type String#
> -    return (mkApps (Var err_id) [Type (getRuntimeRep ty), Type ty, core_msg])
> +    return (mkApps (Var err_id) [Type (getRuntimeInfo ty), Type ty, core_msg])
>  
>  {-
>  'mkCoreAppDs' and 'mkCoreAppsDs' handle the special-case desugaring of 'seq'.
> diff --git a/compiler/GHC/IfaceToCore.hs b/compiler/GHC/IfaceToCore.hs
> index de0fa6f023..b6d1281684 100644
> --- a/compiler/GHC/IfaceToCore.hs
> +++ b/compiler/GHC/IfaceToCore.hs
> @@ -1438,7 +1438,7 @@ tcIfaceExpr (IfaceTuple sort args)
>         ; let con_tys = map exprType args'
>               some_con_args = map Type con_tys ++ args'
>               con_args = case sort of
> -               UnboxedTuple -> map (Type . getRuntimeRep) con_tys ++ some_con_args
> +               UnboxedTuple -> map (Type . getRuntimeInfo) con_tys ++ some_con_args
>                 _            -> some_con_args
>                          -- Put the missing type arguments back in
>               con_id   = dataConWorkId (tyConSingleDataCon tc)
> diff --git a/compiler/GHC/Tc/Gen/HsType.hs b/compiler/GHC/Tc/Gen/HsType.hs
> index bf4b1c91d1..22283296e1 100644
> --- a/compiler/GHC/Tc/Gen/HsType.hs
> +++ b/compiler/GHC/Tc/Gen/HsType.hs
> @@ -1331,7 +1331,7 @@ finish_tuple rn_ty tup_sort tau_tys tau_kinds exp_kind = do
>        check_expected_kind (mkTyConApp tycon tau_tys) liftedTypeKind
>      UnboxedTuple -> do
>        let tycon    = tupleTyCon Unboxed arity
> -          tau_reps = map kindRep tau_kinds
> +          tau_reps = map kindInfo tau_kinds
>            -- See also Note [Unboxed tuple RuntimeRep vars] in GHC.Core.TyCon
>            arg_tys  = tau_reps ++ tau_tys
>            res_kind = unboxedTupleKind tau_reps
> @@ -1340,7 +1340,8 @@ finish_tuple rn_ty tup_sort tau_tys tau_kinds exp_kind = do
>    where
>      arity = length tau_tys
>      check_expected_kind ty act_kind =
> -      checkExpectedKind rn_ty ty act_kind exp_kind
> +      pprPanic "here" (ppr exp_kind)
> +      -- checkExpectedKind rn_ty ty act_kind exp_kind
>  
>  {-
>  Note [Ignore unary constraint tuples]
> diff --git a/compiler/GHC/Tc/Instance/Typeable.hs b/compiler/GHC/Tc/Instance/Typeable.hs
> index e4eb7a1b2d..51f0816860 100644
> --- a/compiler/GHC/Tc/Instance/Typeable.hs
> +++ b/compiler/GHC/Tc/Instance/Typeable.hs
> @@ -28,7 +28,7 @@ import GHC.Builtin.Names
>  import GHC.Builtin.Types.Prim ( primTyCons )
>  import GHC.Builtin.Types
>                    ( tupleTyCon, sumTyCon, runtimeRepTyCon
> -                  , vecCountTyCon, vecElemTyCon
> +                  , runtimeInfoTyCon, vecCountTyCon, vecElemTyCon
>                    , nilDataCon, consDataCon )
>  import GHC.Types.Name
>  import GHC.Types.Id
> @@ -564,7 +564,7 @@ mkKindRepRhs stuff@(Stuff {..}) in_scope = new_kind_rep
>        | not (tcIsConstraintKind k)
>                -- Typeable respects the Constraint/Type distinction
>                -- so do not follow the special case here
> -      , Just arg <- kindRep_maybe k
> +      , Just arg <- kindInfo_maybe k
>        , Just (tc, []) <- splitTyConApp_maybe arg
>        , Just dc <- isPromotedDataCon_maybe tc
>        = return $ nlHsDataCon kindRepTYPEDataCon `nlHsApp` nlHsDataCon dc
> diff --git a/compiler/GHC/Tc/Solver.hs b/compiler/GHC/Tc/Solver.hs
> index 8b21b72768..ae8609541f 100644
> --- a/compiler/GHC/Tc/Solver.hs
> +++ b/compiler/GHC/Tc/Solver.hs
> @@ -53,7 +53,7 @@ import GHC.Core.Predicate
>  import GHC.Tc.Types.Origin
>  import GHC.Tc.Utils.TcType
>  import GHC.Core.Type
> -import GHC.Builtin.Types ( liftedRepTy, manyDataConTy )
> +import GHC.Builtin.Types ( liftedRepEvalTy, manyDataConTy )
>  import GHC.Core.Unify    ( tcMatchTyKi )
>  import GHC.Utils.Misc
>  import GHC.Utils.Panic
> @@ -2283,13 +2283,13 @@ promoteTyVarTcS tv
>  -- | Like 'defaultTyVar', but in the TcS monad.
>  defaultTyVarTcS :: TcTyVar -> TcS Bool
>  defaultTyVarTcS the_tv
> -  | isRuntimeRepVar the_tv
> +  | isRuntimeInfoVar the_tv
>    , not (isTyVarTyVar the_tv)
>      -- TyVarTvs should only be unified with a tyvar
>      -- never with a type; c.f. GHC.Tc.Utils.TcMType.defaultTyVar
>      -- and Note [Inferring kinds for type declarations] in GHC.Tc.TyCl
> -  = do { traceTcS "defaultTyVarTcS RuntimeRep" (ppr the_tv)
> -       ; unifyTyVar the_tv liftedRepTy
> +  = do { traceTcS "defaultTyVarTcS RuntimeInfo" (ppr the_tv)
> +       ; unifyTyVar the_tv liftedRepEvalTy
>         ; return True }
>    | isMultiplicityVar the_tv
>    , not (isTyVarTyVar the_tv)  -- TyVarTvs should only be unified with a tyvar
> diff --git a/compiler/GHC/Tc/TyCl/PatSyn.hs b/compiler/GHC/Tc/TyCl/PatSyn.hs
> index 3f5b10f343..de9f28fbd9 100644
> --- a/compiler/GHC/Tc/TyCl/PatSyn.hs
> +++ b/compiler/GHC/Tc/TyCl/PatSyn.hs
> @@ -756,7 +756,7 @@ tcPatSynMatcher (L loc name) lpat
>                  (args, arg_tys) pat_ty
>    = do { rr_name <- newNameAt (mkTyVarOcc "rep") loc
>         ; tv_name <- newNameAt (mkTyVarOcc "r")   loc
> -       ; let rr_tv  = mkTyVar rr_name runtimeRepTy
> +       ; let rr_tv  = mkTyVar rr_name runtimeInfoTy
>               rr     = mkTyVarTy rr_tv
>               res_tv = mkTyVar tv_name (tYPE rr)
>               res_ty = mkTyVarTy res_tv
> diff --git a/compiler/GHC/Tc/Utils/TcMType.hs b/compiler/GHC/Tc/Utils/TcMType.hs
> index ccb9152e01..67295ac3f5 100644
> --- a/compiler/GHC/Tc/Utils/TcMType.hs
> +++ b/compiler/GHC/Tc/Utils/TcMType.hs
> @@ -492,7 +492,7 @@ inferResultToType (IR { ir_uniq = u, ir_lvl = tc_lvl
>              Just ty -> do { ensureMonoType ty
>                              -- See Note [inferResultToType]
>                            ; return ty }
> -            Nothing -> do { rr  <- newMetaTyVarTyAtLevel tc_lvl runtimeRepTy
> +            Nothing -> do { rr  <- newMetaTyVarTyAtLevel tc_lvl runtimeInfoTy
>                            ; tau <- newMetaTyVarTyAtLevel tc_lvl (tYPE rr)
>                              -- See Note [TcLevel of ExpType]
>                            ; writeMutVar ref (Just tau)
> @@ -667,10 +667,10 @@ promoteTcType dest_lvl ty
>           else promote_it }
>    where
>      promote_it :: TcM (TcCoercion, TcType)
> -    promote_it  -- Emit a constraint  (alpha :: TYPE rr) ~ ty
> +    promote_it  -- Emit a constraint  (alpha :: TYPE ri) ~ ty
>                  -- where alpha and rr are fresh and from level dest_lvl
> -      = do { rr      <- newMetaTyVarTyAtLevel dest_lvl runtimeRepTy
> -           ; prom_ty <- newMetaTyVarTyAtLevel dest_lvl (tYPE rr)
> +      = do { ri      <- newMetaTyVarTyAtLevel dest_lvl runtimeInfoTy
> +           ; prom_ty <- newMetaTyVarTyAtLevel dest_lvl (tYPE ri)
>             ; let eq_orig = TypeEqOrigin { uo_actual   = ty
>                                          , uo_expected = prom_ty
>                                          , uo_thing    = Nothing
> @@ -1048,7 +1048,7 @@ newFlexiTyVarTys n kind = replicateM n (newFlexiTyVarTy kind)
>  
>  newOpenTypeKind :: TcM TcKind
>  newOpenTypeKind
> -  = do { rr <- newFlexiTyVarTy runtimeRepTy
> +  = do { rr <- newFlexiTyVarTy runtimeInfoTy
>         ; return (tYPE rr) }
>  
>  -- | Create a tyvar that can be a lifted or unlifted type.
> @@ -1765,11 +1765,16 @@ defaultTyVar default_kind tv
>      -- See Note [Inferring kinds for type declarations] in GHC.Tc.TyCl
>    = return False
>  
> +  | isRuntimeInfoVar tv  -- Do not quantify over a RuntimeRep var
> +                        -- unless it is a TyVarTv, handled earlier
> +  = do { traceTc "Defaulting a RuntimeRep var to LiftedRep" (ppr tv)
> +       ; writeMetaTyVar tv liftedRepEvalTy
> +       ; return True }
>  
>    | isRuntimeRepVar tv  -- Do not quantify over a RuntimeRep var
>                          -- unless it is a TyVarTv, handled earlier
>    = do { traceTc "Defaulting a RuntimeRep var to LiftedRep" (ppr tv)
> -       ; writeMetaTyVar tv liftedRepTy
> +       ; writeMetaTyVar tv liftedRepEvalTy

I believe your bug is here. You have filled in a RuntimeRep metavar with
a RuntimeInfo. Leave this as liftedRepTy.

Cheers,

- Ben
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 487 bytes
Desc: not available
URL: <http://mail.haskell.org/pipermail/ghc-devs/attachments/20210407/125639f2/attachment.sig>


More information about the ghc-devs mailing list