Remove LevityInfo

Every Id was storing a boolean whether it could be levity-polymorphic.
This information is no longer needed since representation-checking
has been moved to the typechecker.

11 files changed, 14 insertions, 129 deletions

diff --git a/compiler/GHC/Builtin/PrimOps/Ids.hs b/compiler/GHC/Builtin/PrimOps/Ids.hs
index cf6f846f77..9c6984a018 100644
--- a/compiler/GHC/Builtin/PrimOps/Ids.hs
+++ b/compiler/GHC/Builtin/PrimOps/Ids.hs
@@ -51,7 +51,6 @@ mkPrimOpId prim_op
            `setDmdSigInfo`         strict_sig
            `setCprSigInfo`         mkCprSig arity cpr
            `setInlinePragInfo`     neverInlinePragma
-           `setLevityInfoWithType` res_ty
                -- We give PrimOps a NOINLINE pragma so that we don't
                -- get silly warnings from Desugar.dsRule (the inline_shadows_rule
                -- test) about a RULE conflicting with a possible inlining
diff --git a/compiler/GHC/Core/Type.hs b/compiler/GHC/Core/Type.hs
index bc864c301f..fbe499ee79 100644
--- a/compiler/GHC/Core/Type.hs
+++ b/compiler/GHC/Core/Type.hs
@@ -149,7 +149,7 @@ module GHC.Core.Type (
         Kind,
 
         -- ** Finding the kind of a type
-        typeKind, tcTypeKind, typeHasFixedRuntimeRep, resultHasFixedRuntimeRep,
+        typeKind, tcTypeKind, typeHasFixedRuntimeRep,
         tcIsLiftedTypeKind, tcIsConstraintKind, tcReturnsConstraintKind,
         tcIsBoxedTypeKind, tcIsRuntimeTypeKind,
 
@@ -3194,16 +3194,6 @@ typeHasFixedRuntimeRep = go
     go (ForAllTy _ ty)          = go ty
     go ty                       = isFixedRuntimeRepKind (typeKind ty)
 
--- | Looking past all pi-types, does the end result have a
--- fixed runtime rep, as per Note [Fixed RuntimeRep] in GHC.Tc.Utils.Concrete?
---
--- Examples:
---
---   * False for @(forall r (a :: TYPE r). String -> a)@
---   * True for @(forall r1 r2 (a :: TYPE r1) (b :: TYPE r2). a -> b -> Type)@
-resultHasFixedRuntimeRep :: Type -> Bool
-resultHasFixedRuntimeRep = typeHasFixedRuntimeRep . snd . splitPiTys
-
 {- **********************************************************************
 *                                                                       *
            Occurs check expansion
diff --git a/compiler/GHC/Core/Utils.hs b/compiler/GHC/Core/Utils.hs
index 43dd5169e1..d6653fd387 100644
--- a/compiler/GHC/Core/Utils.hs
+++ b/compiler/GHC/Core/Utils.hs
@@ -2280,7 +2280,6 @@ diffIdInfo env bndr1 bndr2
     && occInfo info1 == occInfo info2
     && demandInfo info1 == demandInfo info2
     && callArityInfo info1 == callArityInfo info2
-    && levityInfo info1 == levityInfo info2
   = locBind "in unfolding of" bndr1 bndr2 $
     diffUnfold env (realUnfoldingInfo info1) (realUnfoldingInfo info2)
   | otherwise
diff --git a/compiler/GHC/CoreToIface.hs b/compiler/GHC/CoreToIface.hs
index 11fd63e0bc..de9d13d7aa 100644
--- a/compiler/GHC/CoreToIface.hs
+++ b/compiler/GHC/CoreToIface.hs
@@ -458,7 +458,7 @@ toIfaceIdDetails other = pprTrace "toIfaceIdDetails" (ppr other)
 toIfaceIdInfo :: IdInfo -> IfaceIdInfo
 toIfaceIdInfo id_info
   = catMaybes [arity_hsinfo, caf_hsinfo, strict_hsinfo, cpr_hsinfo,
-               inline_hsinfo,  unfold_hsinfo, levity_hsinfo]
+               inline_hsinfo,  unfold_hsinfo]
                -- NB: strictness and arity must appear in the list before unfolding
                -- See GHC.IfaceToCore.tcUnfolding
   where
@@ -492,10 +492,6 @@ toIfaceIdInfo id_info
     inline_hsinfo | isDefaultInlinePragma inline_prag = Nothing
                   | otherwise = Just (HsInline inline_prag)
 
-    ------------  Representation polymorphism  ----------
-    levity_hsinfo | isNeverRepPolyIdInfo id_info = Just HsLevity
-                  | otherwise                    = Nothing
-
 toIfaceJoinInfo :: Maybe JoinArity -> IfaceJoinInfo
 toIfaceJoinInfo (Just ar) = IfaceJoinPoint ar
 toIfaceJoinInfo Nothing   = IfaceNotJoinPoint
diff --git a/compiler/GHC/Iface/Syntax.hs b/compiler/GHC/Iface/Syntax.hs
index c735a2f94f..9b89d7f145 100644
--- a/compiler/GHC/Iface/Syntax.hs
+++ b/compiler/GHC/Iface/Syntax.hs
@@ -351,7 +351,6 @@ data IfaceInfoItem
   | HsUnfold        Bool             -- True <=> isStrongLoopBreaker is true
                     IfaceUnfolding   -- See Note [Expose recursive functions]
   | HsNoCafRefs
-  | HsLevity                         -- Present <=> never representation-polymorphic
   | HsLFInfo        IfaceLFInfo
   | HsTagSig        TagSig
 
@@ -1478,7 +1477,6 @@ instance Outputable IfaceInfoItem where
   ppr (HsDmdSig str)        = text "Strictness:" <+> ppr str
   ppr (HsCprSig cpr)        = text "CPR:" <+> ppr cpr
   ppr HsNoCafRefs           = text "HasNoCafRefs"
-  ppr HsLevity              = text "Never levity-polymorphic"
   ppr (HsLFInfo lf_info)    = text "LambdaFormInfo:" <+> ppr lf_info
   ppr (HsTagSig tag_sig)    = text "TagSig:" <+> ppr tag_sig
 
@@ -2244,7 +2242,6 @@ instance Binary IfaceInfoItem where
     put_ bh (HsUnfold lb ad)      = putByte bh 2 >> put_ bh lb >> put_ bh ad
     put_ bh (HsInline ad)         = putByte bh 3 >> put_ bh ad
     put_ bh HsNoCafRefs           = putByte bh 4
-    put_ bh HsLevity              = putByte bh 5
     put_ bh (HsCprSig cpr)        = putByte bh 6 >> put_ bh cpr
     put_ bh (HsLFInfo lf_info)    = putByte bh 7 >> put_ bh lf_info
     put_ bh (HsTagSig sig)        = putByte bh 8 >> put_ bh sig
@@ -2259,7 +2256,6 @@ instance Binary IfaceInfoItem where
                     return (HsUnfold lb ad)
             3 -> liftM HsInline $ get bh
             4 -> return HsNoCafRefs
-            5 -> return HsLevity
             6 -> HsCprSig <$> get bh
             7 -> HsLFInfo <$> get bh
             _ -> HsTagSig <$> get bh
@@ -2607,7 +2603,6 @@ instance NFData IfaceInfoItem where
     HsInline p -> p `seq` () -- TODO: seq further?
     HsUnfold b unf -> rnf b `seq` rnf unf
     HsNoCafRefs -> ()
-    HsLevity -> ()
     HsCprSig cpr -> cpr `seq` ()
     HsLFInfo lf_info -> lf_info `seq` () -- TODO: seq further?
     HsTagSig sig -> sig `seq` ()
diff --git a/compiler/GHC/IfaceToCore.hs b/compiler/GHC/IfaceToCore.hs
index a248cbf767..407f7b1980 100644
--- a/compiler/GHC/IfaceToCore.hs
+++ b/compiler/GHC/IfaceToCore.hs
@@ -1662,7 +1662,6 @@ tcIdInfo ignore_prags toplvl name ty info = do
     tcPrag info (HsDmdSig str)     = return (info `setDmdSigInfo` str)
     tcPrag info (HsCprSig cpr)     = return (info `setCprSigInfo` cpr)
     tcPrag info (HsInline prag)    = return (info `setInlinePragInfo` prag)
-    tcPrag info HsLevity           = return (info `setNeverRepPoly` ty)
     tcPrag info (HsLFInfo lf_info) = do
       lf_info <- tcLFInfo lf_info
       return (info `setLFInfo` lf_info)
diff --git a/compiler/GHC/Tc/TyCl/PatSyn.hs b/compiler/GHC/Tc/TyCl/PatSyn.hs
index 6e7316d544..46691958a6 100644
--- a/compiler/GHC/Tc/TyCl/PatSyn.hs
+++ b/compiler/GHC/Tc/TyCl/PatSyn.hs
@@ -43,7 +43,7 @@ import GHC.Data.FastString
 import GHC.Types.Var
 import GHC.Types.Var.Env( emptyTidyEnv, mkInScopeSet )
 import GHC.Types.Id
-import GHC.Types.Id.Info( RecSelParent(..), setLevityInfoWithType )
+import GHC.Types.Id.Info( RecSelParent(..) )
 import GHC.Tc.Gen.Bind
 import GHC.Types.Basic
 import GHC.Tc.Solver
@@ -910,9 +910,7 @@ tcPatSynBuilderBind prag_fn (PSB { psb_id = ps_lname@(L loc ps_name)
 
            Just (builder_name, builder_ty, need_dummy_arg) ->  -- Normal case
     do { -- Bidirectional, so patSynBuilder returns Just
-         let pat_ty = patSynResultType patsyn
-             builder_id = modifyIdInfo (`setLevityInfoWithType` pat_ty) $
-                          mkExportedVanillaId builder_name builder_ty
+         let builder_id = mkExportedVanillaId builder_name builder_ty
                          -- See Note [Exported LocalIds] in GHC.Types.Id
              prags = lookupPragEnv prag_fn ps_name
              -- See Note [Pragmas for pattern synonyms]
diff --git a/compiler/GHC/Tc/Utils/Zonk.hs b/compiler/GHC/Tc/Utils/Zonk.hs
index 0747db57e4..eee43e8ed1 100644
--- a/compiler/GHC/Tc/Utils/Zonk.hs
+++ b/compiler/GHC/Tc/Utils/Zonk.hs
@@ -78,7 +78,6 @@ import GHC.Types.Name.Env
 import GHC.Types.Var
 import GHC.Types.Var.Env
 import GHC.Types.Id
-import GHC.Types.Id.Info
 import GHC.Types.TypeEnv
 import GHC.Types.SourceText
 import GHC.Types.Basic
@@ -385,7 +384,7 @@ zonkIdOccs env ids = map (zonkIdOcc env) ids
 zonkIdBndr :: ZonkEnv -> TcId -> TcM Id
 zonkIdBndr env v
   = do Scaled w' ty' <- zonkScaledTcTypeToTypeX env (idScaledType v)
-       return (modifyIdInfo (`setLevityInfoWithType` ty') (setIdMult (setIdType v ty') w'))
+       return (setIdMult (setIdType v ty') w')
 
 zonkIdBndrs :: ZonkEnv -> [TcId] -> TcM [Id]
 zonkIdBndrs env ids = mapM (zonkIdBndr env) ids
diff --git a/compiler/GHC/Types/Id.hs b/compiler/GHC/Types/Id.hs
index 4d04c82a35..d5b308a550 100644
--- a/compiler/GHC/Types/Id.hs
+++ b/compiler/GHC/Types/Id.hs
@@ -99,7 +99,6 @@ module GHC.Types.Id (
         idCafInfo, idLFInfo_maybe,
         idOneShotInfo, idStateHackOneShotInfo,
         idOccInfo,
-        isNeverRepPolyId,
 
         -- ** Writing 'IdInfo' fields
         setIdUnfolding, setCaseBndrEvald,
@@ -1077,6 +1076,3 @@ transferPolyIdInfo old_id abstract_wrt new_id
                                  `setOccInfo` new_occ_info
                                  `setDmdSigInfo` new_strictness
                                  `setCprSigInfo` old_cpr
-
-isNeverRepPolyId :: Id -> Bool
-isNeverRepPolyId = isNeverRepPolyIdInfo . idInfo
diff --git a/compiler/GHC/Types/Id/Info.hs b/compiler/GHC/Types/Id/Info.hs
index 4bbf0ba86f..1b4ee7ae1c 100644
--- a/compiler/GHC/Types/Id/Info.hs
+++ b/compiler/GHC/Types/Id/Info.hs
@@ -83,10 +83,6 @@ module GHC.Types.Id.Info (
 
         -- ** Tick-box Info
         TickBoxOp(..), TickBoxId,
-
-        -- ** Levity info
-        LevityInfo, levityInfo, setNeverRepPoly, setLevityInfoWithType,
-        isNeverRepPolyIdInfo
     ) where
 
 import GHC.Prelude
@@ -100,13 +96,11 @@ import GHC.Types.Basic
 import GHC.Core.DataCon
 import GHC.Core.TyCon
 import GHC.Core.PatSyn
-import GHC.Core.Type
 import GHC.Types.ForeignCall
 import GHC.Unit.Module
 import GHC.Types.Demand
 import GHC.Types.Cpr
 
-import GHC.Utils.Misc
 import GHC.Utils.Outputable
 import GHC.Utils.Panic
 import GHC.Utils.Panic.Plain
@@ -126,9 +120,7 @@ infixl  1 `setRuleInfo`,
           `setCafInfo`,
           `setDmdSigInfo`,
           `setCprSigInfo`,
-          `setDemandInfo`,
-          `setNeverRepPoly`,
-          `setLevityInfoWithType`
+          `setDemandInfo`
 {-
 ************************************************************************
 *                                                                      *
@@ -337,7 +329,7 @@ data IdInfo
         demandInfo      :: Demand,
         -- ^ ID demand information
         bitfield        :: {-# UNPACK #-} !BitField,
-        -- ^ Bitfield packs CafInfo, OneShotInfo, arity info, LevityInfo, and
+        -- ^ Bitfield packs CafInfo, OneShotInfo, arity info, and
         -- call arity info in one 64-bit word. Packing these fields reduces size
         -- of `IdInfo` from 12 words to 7 words and reduces residency by almost
         -- 4% in some programs. See #17497 and associated MR.
@@ -349,12 +341,12 @@ data IdInfo
         tagSig          :: !(Maybe TagSig)
     }
 
--- | Encodes arities, OneShotInfo, CafInfo and LevityInfo.
+-- | Encodes arities, OneShotInfo, CafInfo.
 -- From least-significant to most-significant bits:
 --
 -- - Bit   0   (1):  OneShotInfo
 -- - Bit   1   (1):  CafInfo
--- - Bit   2   (1):  LevityInfo
+-- - Bit   2   (1):  unused
 -- - Bits  3-32(30): Call Arity info
 -- - Bits 33-62(30): Arity info
 --
@@ -371,10 +363,6 @@ bitfieldGetCafInfo :: BitField -> CafInfo
 bitfieldGetCafInfo (BitField bits) =
     if testBit bits 1 then NoCafRefs else MayHaveCafRefs
 
-bitfieldGetLevityInfo :: BitField -> LevityInfo
-bitfieldGetLevityInfo (BitField bits) =
-    if testBit bits 2 then NeverLevityPolymorphic else NoLevityInfo
-
 bitfieldGetCallArityInfo :: BitField -> ArityInfo
 bitfieldGetCallArityInfo (BitField bits) =
     fromIntegral (bits `shiftR` 3) .&. ((1 `shiftL` 30) - 1)
@@ -395,12 +383,6 @@ bitfieldSetCafInfo info (BitField bits) =
       MayHaveCafRefs -> BitField (clearBit bits 1)
       NoCafRefs -> BitField (setBit bits 1)
 
-bitfieldSetLevityInfo :: LevityInfo -> BitField -> BitField
-bitfieldSetLevityInfo info (BitField bits) =
-    case info of
-      NoLevityInfo -> BitField (clearBit bits 2)
-      NeverLevityPolymorphic -> BitField (setBit bits 2)
-
 bitfieldSetCallArityInfo :: ArityInfo -> BitField -> BitField
 bitfieldSetCallArityInfo info bf@(BitField bits) =
     assert (info < 2^(30 :: Int) - 1) $
@@ -414,10 +396,6 @@ bitfieldSetArityInfo info (BitField bits) =
 
 -- Getters
 
--- | When applied, will this Id ever have a representation-polymorphic type?
-levityInfo :: IdInfo -> LevityInfo
-levityInfo = bitfieldGetLevityInfo . bitfield
-
 -- | Info about a lambda-bound variable, if the 'Id' is one
 oneShotInfo :: IdInfo -> OneShotInfo
 oneShotInfo = bitfieldGetOneShotInfo . bitfield
@@ -520,7 +498,6 @@ vanillaIdInfo
                              bitfieldSetArityInfo unknownArity $
                              bitfieldSetCallArityInfo unknownArity $
                              bitfieldSetOneShotInfo NoOneShotInfo $
-                             bitfieldSetLevityInfo NoLevityInfo $
                              emptyBitField,
             lfInfo         = Nothing,
             tagSig         = Nothing
@@ -835,55 +812,3 @@ data TickBoxOp
 
 instance Outputable TickBoxOp where
     ppr (TickBox mod n)         = text "tick" <+> ppr (mod,n)
-
-{-
-************************************************************************
-*                                                                      *
-   Levity
-*                                                                      *
-************************************************************************
-
-Note [Levity info]
-~~~~~~~~~~~~~~~~~~
-
-Ids store whether or not they can be representation-polymorphic at any amount
-of saturation. This is helpful in optimizing representation polymorphism checks,
-allowing us to learn that something is not representation-polymorphic without
-actually figuring out its type.
-See exprHasFixedRuntimeRep in GHC.Core.Utils for where this info is used.
-
-Historical note: this was very important when representation polymorphism
-was checked in the desugarer (it was needed to prevent T5631 from blowing up).
-It's less important now that the checks happen in the typechecker, but remains useful.
-Refer to Note [The Concrete mechanism] in GHC.Tc.Utils.Concrete for details
-about the new approach being used.
--}
-
--- See Note [Levity info]
-data LevityInfo = NoLevityInfo  -- always safe
-                | NeverLevityPolymorphic
-  deriving Eq
-
-instance Outputable LevityInfo where
-  ppr NoLevityInfo           = text "NoLevityInfo"
-  ppr NeverLevityPolymorphic = text "NeverLevityPolymorphic"
-
--- | Marks an IdInfo describing an Id that is never representation-polymorphic
--- (even when applied). The Type is only there for checking that it's really
--- never representation-polymorphic.
-setNeverRepPoly :: HasDebugCallStack => IdInfo -> Type -> IdInfo
-setNeverRepPoly info ty
-  = assertPpr (resultHasFixedRuntimeRep ty) (ppr ty) $
-    info { bitfield = bitfieldSetLevityInfo NeverLevityPolymorphic (bitfield info) }
-
-setLevityInfoWithType :: IdInfo -> Type -> IdInfo
-setLevityInfoWithType info ty
-  | resultHasFixedRuntimeRep ty
-  = info { bitfield = bitfieldSetLevityInfo NeverLevityPolymorphic (bitfield info) }
-  | otherwise
-  = info
-
-isNeverRepPolyIdInfo :: IdInfo -> Bool
-isNeverRepPolyIdInfo info
-  | NeverLevityPolymorphic <- levityInfo info = True
-  | otherwise                                 = False
diff --git a/compiler/GHC/Types/Id/Make.hs b/compiler/GHC/Types/Id/Make.hs
index cfacdc9f70..4180e557c8 100644
--- a/compiler/GHC/Types/Id/Make.hs
+++ b/compiler/GHC/Types/Id/Make.hs
@@ -479,7 +479,6 @@ mkDictSelId name clas
                 `setArityInfo`          1
                 `setDmdSigInfo`     strict_sig
                 `setCprSigInfo`            topCprSig
-                `setLevityInfoWithType` sel_ty
 
     info | new_tycon
          = base_info `setInlinePragInfo` alwaysInlinePragma
@@ -585,9 +584,6 @@ mkDataConWorkId wkr_name data_con
                    `setInlinePragInfo`     wkr_inline_prag
                    `setUnfoldingInfo`      evaldUnfolding  -- Record that it's evaluated,
                                                            -- even if arity = 0
-                   `setLevityInfoWithType` wkr_ty
-                     -- NB: unboxed tuples have workers, so we can't use
-                     -- setNeverRepPoly
 
     wkr_inline_prag = defaultInlinePragma { inl_rule = ConLike }
     wkr_arity = dataConRepArity data_con
@@ -598,7 +594,6 @@ mkDataConWorkId wkr_name data_con
                   `setArityInfo` 1      -- Arity 1
                   `setInlinePragInfo`     dataConWrapperInlinePragma
                   `setUnfoldingInfo`      newtype_unf
-                  `setLevityInfoWithType` wkr_ty
     id_arg1      = mkScaledTemplateLocal 1 (head arg_tys)
     res_ty_args  = mkTyCoVarTys univ_tvs
     newtype_unf  = assertPpr (isVanillaDataCon data_con && isSingleton arg_tys)
@@ -698,7 +693,6 @@ mkDataConRep dc_bang_opts fam_envs wrap_name data_con
                              -- We need to get the CAF info right here because GHC.Iface.Tidy
                              -- does not tidy the IdInfo of implicit bindings (like the wrapper)
                              -- so it not make sure that the CAF info is sane
-                         `setLevityInfoWithType` wrap_ty
 
              wrap_sig = mkClosedDmdSig wrap_arg_dmds topDiv
 
@@ -1323,7 +1317,6 @@ mkFCallId uniq fcall ty
            `setArityInfo`          arity
            `setDmdSigInfo`     strict_sig
            `setCprSigInfo`            topCprSig
-           `setLevityInfoWithType` ty
 
     (bndrs, _) = tcSplitPiTys ty
     arity      = count isAnonTyCoBinder bndrs
@@ -1411,8 +1404,7 @@ noinlineIdName    = mkWiredInIdName gHC_MAGIC (fsLit "noinline")       noinlineI
 proxyHashId :: Id
 proxyHashId
   = pcMiscPrelId proxyName ty
-       (noCafIdInfo `setUnfoldingInfo` evaldUnfolding -- Note [evaldUnfoldings]
-                    `setNeverRepPoly`  ty)
+       (noCafIdInfo `setUnfoldingInfo` evaldUnfolding) -- Note [evaldUnfoldings]
   where
     -- proxy# :: forall {k} (a:k). Proxy# k a
     --
@@ -1432,7 +1424,6 @@ nullAddrId = pcMiscPrelId nullAddrName addrPrimTy info
   where
     info = noCafIdInfo `setInlinePragInfo` alwaysInlinePragma
                        `setUnfoldingInfo`  mkCompulsoryUnfolding defaultSimpleOpts (Lit nullAddrLit)
-                       `setNeverRepPoly`   addrPrimTy
 
 ------------------------------------------------
 seqId :: Id     -- See Note [seqId magic]
@@ -1466,13 +1457,13 @@ seqId = pcMiscPrelId seqName ty info
 lazyId :: Id    -- See Note [lazyId magic]
 lazyId = pcMiscPrelId lazyIdName ty info
   where
-    info = noCafIdInfo `setNeverRepPoly` ty
+    info = noCafIdInfo
     ty  = mkSpecForAllTys [alphaTyVar] (mkVisFunTyMany alphaTy alphaTy)
 
 noinlineId :: Id -- See Note [noinlineId magic]
 noinlineId = pcMiscPrelId noinlineIdName ty info
   where
-    info = noCafIdInfo `setNeverRepPoly` ty
+    info = noCafIdInfo
     ty  = mkSpecForAllTys [alphaTyVar] (mkVisFunTyMany alphaTy alphaTy)
 
 oneShotId :: Id -- See Note [The oneShot function]
@@ -1784,8 +1775,7 @@ inlined.
 realWorldPrimId :: Id   -- :: State# RealWorld
 realWorldPrimId = pcMiscPrelId realWorldName realWorldStatePrimTy
                      (noCafIdInfo `setUnfoldingInfo` evaldUnfolding    -- Note [evaldUnfoldings]
-                                  `setOneShotInfo`   stateHackOneShot
-                                  `setNeverRepPoly`  realWorldStatePrimTy)
+                                  `setOneShotInfo`   stateHackOneShot)
 
 voidPrimId :: Id     -- Global constant :: Void#
                      -- The type Void# is now the same as (# #) (ticket #18441),
@@ -1794,8 +1784,7 @@ voidPrimId :: Id     -- Global constant :: Void#
                      -- We cannot define it in normal Haskell, since it's
                      -- a top-level unlifted value.
 voidPrimId  = pcMiscPrelId voidPrimIdName unboxedUnitTy
-                (noCafIdInfo `setUnfoldingInfo` mkCompulsoryUnfolding defaultSimpleOpts rhs
-                             `setNeverRepPoly`  unboxedUnitTy)
+                (noCafIdInfo `setUnfoldingInfo` mkCompulsoryUnfolding defaultSimpleOpts rhs)
     where rhs = Var (dataConWorkId unboxedUnitDataCon)