Refactor: make primtypes independent of PrimRepswip/prim-reps-cleanup

Previously, 'pcPrimTyCon', the function used to define a primitive type,
was taking a PrimRep, only to convert it to a RuntimeRep. Now it takes
a RuntimeRep directly.

Moved primRepToRuntimeRep to GHC.Types.RepType. It is now
located next to its inverse function runtimeRepPrimRep.
Now GHC.Builtin.Types.Prim no longer mentions PrimRep, and GHC.Types.RepType
no longer imports GHC.Builtin.Types.Prim.

Removed unused functions `primRepsToRuntimeRep` and `mkTupleRep`.

Removed Note [PrimRep and kindPrimRep] - it was never referenced,
didn't belong to Types.Prim, and Note [Getting from RuntimeRep to
PrimRep] is more comprehensive.

5 files changed, 106 insertions, 126 deletions

diff --git a/compiler/GHC/Builtin/Types.hs-boot b/compiler/GHC/Builtin/Types.hs-boot
index a8b499013a..f65781f1d7 100644
--- a/compiler/GHC/Builtin/Types.hs-boot
+++ b/compiler/GHC/Builtin/Types.hs-boot
@@ -53,7 +53,6 @@ int8ElemRepDataConTy, int16ElemRepDataConTy, int32ElemRepDataConTy,
 
 anyTypeOfKind :: Kind -> Type
 unboxedTupleKind :: [Type] -> Type
-mkPromotedListTy :: Type -> [Type] -> Type
 
 multiplicityTyCon :: TyCon
 multiplicityTy :: Type
diff --git a/compiler/GHC/Builtin/Types/Prim.hs b/compiler/GHC/Builtin/Types/Prim.hs
index f5ff25523a..bf33710e4d 100644
--- a/compiler/GHC/Builtin/Types/Prim.hs
+++ b/compiler/GHC/Builtin/Types/Prim.hs
@@ -46,7 +46,7 @@ module GHC.Builtin.Types.Prim(
         tYPETyCon, tYPETyConName,
 
         -- Kinds
-        mkTYPEapp, primRepToRuntimeRep, primRepsToRuntimeRep,
+        mkTYPEapp,
 
         functionWithMultiplicity,
         funTyCon, funTyConName,
@@ -110,7 +110,7 @@ import GHC.Prelude
 
 import {-# SOURCE #-} GHC.Builtin.Types
   ( runtimeRepTy, levityTy, unboxedTupleKind, liftedTypeKind
-  , boxedRepDataConTyCon, vecRepDataConTyCon, tupleRepDataConTyCon
+  , boxedRepDataConTyCon, vecRepDataConTyCon
   , liftedRepTy, unliftedRepTy, zeroBitRepTy
   , intRepDataConTy
   , int8RepDataConTy, int16RepDataConTy, int32RepDataConTy, int64RepDataConTy
@@ -124,7 +124,7 @@ import {-# SOURCE #-} GHC.Builtin.Types
   , int64ElemRepDataConTy, word8ElemRepDataConTy, word16ElemRepDataConTy
   , word32ElemRepDataConTy, word64ElemRepDataConTy, floatElemRepDataConTy
   , doubleElemRepDataConTy
-  , mkPromotedListTy, multiplicityTy )
+  , multiplicityTy )
 
 import GHC.Types.Var    ( TyVarBinder, TyVar
                         , mkTyVar, mkTyVarBinder, mkTyVarBinders )
@@ -137,8 +137,6 @@ import GHC.Builtin.Uniques
 import GHC.Builtin.Names
 import GHC.Data.FastString
 import GHC.Utils.Misc ( changeLast )
-import GHC.Utils.Outputable
-import GHC.Utils.Panic
 import GHC.Core.TyCo.Rep -- Doesn't need special access, but this is easier to avoid
                          -- import loops which show up if you import Type instead
 import {-# SOURCE #-} GHC.Core.Type ( mkTyConTy, mkTyConApp, mkTYPEapp, getLevity )
@@ -576,29 +574,6 @@ generator never has to manipulate a value of type 'a :: TYPE rr'.
                      (a :: TYPE r1) (b :: TYPE r2).
                      a -> b -> TYPE ('TupleRep '[r1, r2])
 
-Note [PrimRep and kindPrimRep]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-As part of its source code, in GHC.Core.TyCon, GHC has
-  data PrimRep = BoxedRep Levity | IntRep | FloatRep | ...etc...
-
-Notice that
- * RuntimeRep is part of the syntax tree of the program being compiled
-     (defined in a library: ghc-prim:GHC.Types)
- * PrimRep is part of GHC's source code.
-     (defined in GHC.Core.TyCon)
-
-We need to get from one to the other; that is what kindPrimRep does.
-Suppose we have a value
-   (v :: t) where (t :: k)
-Given this kind
-    k = TyConApp "TYPE" [rep]
-GHC needs to be able to figure out how 'v' is represented at runtime.
-It expects 'rep' to be form
-    TyConApp rr_dc args
-where 'rr_dc' is a promoteed data constructor from RuntimeRep. So
-now we need to go from 'dc' to the corresponding PrimRep.  We store this
-PrimRep in the promoted data constructor itself: see TyCon.promDcRepInfo.
-
 -}
 
 tYPETyCon :: TyCon
@@ -645,19 +620,19 @@ functionWithMultiplicity mul = TyConApp funTyCon [mul]
 --
 -- Only use this in "GHC.Builtin.Types.Prim".
 pcPrimTyCon :: Name
-            -> [Role] -> PrimRep -> TyCon
+            -> [Role] -> RuntimeRepType -> TyCon
 pcPrimTyCon name roles res_rep
   = mkPrimTyCon name binders result_kind roles
   where
     bndr_kis    = liftedTypeKind <$ roles
     binders     = mkTemplateAnonTyConBinders bndr_kis
-    result_kind = mkTYPEapp (primRepToRuntimeRep res_rep)
+    result_kind = mkTYPEapp res_rep
 
 -- | Create a primitive nullary 'TyCon' with the given 'Name'
 -- and result kind representation.
 --
 -- Only use this in "GHC.Builtin.Types.Prim".
-pcPrimTyCon0 :: Name -> PrimRep -> TyCon
+pcPrimTyCon0 :: Name -> RuntimeRepType -> TyCon
 pcPrimTyCon0 name res_rep
   = pcPrimTyCon name [] res_rep
 
@@ -669,12 +644,12 @@ pcPrimTyCon_LevPolyLastArg :: Name
                            -> [Role] -- ^ roles of the arguments (must be non-empty),
                                      -- not including the implicit argument of kind 'Levity',
                                      -- which always has 'Nominal' role
-                           -> PrimRep
+                           -> RuntimeRepType  -- ^ representation of the fully-applied type
                            -> TyCon
 pcPrimTyCon_LevPolyLastArg name roles res_rep
   = mkPrimTyCon name binders result_kind (Nominal : roles)
     where
-      result_kind = mkTYPEapp (primRepToRuntimeRep res_rep)
+      result_kind = mkTYPEapp res_rep
       lev_bndr = mkNamedTyConBinder Inferred levity1TyVar
       binders  = lev_bndr : mkTemplateAnonTyConBinders anon_bndr_kis
       lev_tv   = mkTyVarTy (binderVar lev_bndr)
@@ -683,129 +658,75 @@ pcPrimTyCon_LevPolyLastArg name roles res_rep
       anon_bndr_kis = changeLast (liftedTypeKind <$ roles)
                         (mkTYPEapp $ mkTyConApp boxedRepDataConTyCon [lev_tv])
 
--- | Convert a 'PrimRep' to a 'Type' of kind RuntimeRep
--- Defined here to avoid (more) module loops
-primRepToRuntimeRep :: PrimRep -> Type
-primRepToRuntimeRep rep = case rep of
-  VoidRep       -> zeroBitRepTy
-  LiftedRep     -> liftedRepTy
-  UnliftedRep   -> unliftedRepTy
-  IntRep        -> intRepDataConTy
-  Int8Rep       -> int8RepDataConTy
-  Int16Rep      -> int16RepDataConTy
-  Int32Rep      -> int32RepDataConTy
-  Int64Rep      -> int64RepDataConTy
-  WordRep       -> wordRepDataConTy
-  Word8Rep      -> word8RepDataConTy
-  Word16Rep     -> word16RepDataConTy
-  Word32Rep     -> word32RepDataConTy
-  Word64Rep     -> word64RepDataConTy
-  AddrRep       -> addrRepDataConTy
-  FloatRep      -> floatRepDataConTy
-  DoubleRep     -> doubleRepDataConTy
-  VecRep n elem -> TyConApp vecRepDataConTyCon [n', elem']
-    where
-      n' = case n of
-        2  -> vec2DataConTy
-        4  -> vec4DataConTy
-        8  -> vec8DataConTy
-        16 -> vec16DataConTy
-        32 -> vec32DataConTy
-        64 -> vec64DataConTy
-        _  -> pprPanic "Disallowed VecCount" (ppr n)
-
-      elem' = case elem of
-        Int8ElemRep   -> int8ElemRepDataConTy
-        Int16ElemRep  -> int16ElemRepDataConTy
-        Int32ElemRep  -> int32ElemRepDataConTy
-        Int64ElemRep  -> int64ElemRepDataConTy
-        Word8ElemRep  -> word8ElemRepDataConTy
-        Word16ElemRep -> word16ElemRepDataConTy
-        Word32ElemRep -> word32ElemRepDataConTy
-        Word64ElemRep -> word64ElemRepDataConTy
-        FloatElemRep  -> floatElemRepDataConTy
-        DoubleElemRep -> doubleElemRepDataConTy
-
--- | Given a list of types representing 'RuntimeRep's @reps@, construct
--- @'TupleRep' reps@.
-mkTupleRep :: [Type] -> Type
-mkTupleRep reps = TyConApp tupleRepDataConTyCon [mkPromotedListTy runtimeRepTy reps]
-
--- | Convert a list of 'PrimRep's to a 'Type' of kind RuntimeRep
--- Defined here to avoid (more) module loops
-primRepsToRuntimeRep :: [PrimRep] -> Type
-primRepsToRuntimeRep [rep] = primRepToRuntimeRep rep
-primRepsToRuntimeRep reps  = mkTupleRep $ map primRepToRuntimeRep reps
-
 charPrimTy :: Type
 charPrimTy      = mkTyConTy charPrimTyCon
 charPrimTyCon :: TyCon
-charPrimTyCon   = pcPrimTyCon0 charPrimTyConName WordRep
+charPrimTyCon   = pcPrimTyCon0 charPrimTyConName wordRepDataConTy
 
 intPrimTy :: Type
 intPrimTy       = mkTyConTy intPrimTyCon
 intPrimTyCon :: TyCon
-intPrimTyCon    = pcPrimTyCon0 intPrimTyConName IntRep
+intPrimTyCon    = pcPrimTyCon0 intPrimTyConName intRepDataConTy
 
 int8PrimTy :: Type
 int8PrimTy     = mkTyConTy int8PrimTyCon
 int8PrimTyCon :: TyCon
-int8PrimTyCon  = pcPrimTyCon0 int8PrimTyConName Int8Rep
+int8PrimTyCon  = pcPrimTyCon0 int8PrimTyConName int8RepDataConTy
 
 int16PrimTy :: Type
 int16PrimTy    = mkTyConTy int16PrimTyCon
 int16PrimTyCon :: TyCon
-int16PrimTyCon = pcPrimTyCon0 int16PrimTyConName Int16Rep
+int16PrimTyCon = pcPrimTyCon0 int16PrimTyConName int16RepDataConTy
 
 int32PrimTy :: Type
 int32PrimTy     = mkTyConTy int32PrimTyCon
 int32PrimTyCon :: TyCon
-int32PrimTyCon  = pcPrimTyCon0 int32PrimTyConName Int32Rep
+int32PrimTyCon  = pcPrimTyCon0 int32PrimTyConName int32RepDataConTy
 
 int64PrimTy :: Type
 int64PrimTy     = mkTyConTy int64PrimTyCon
 int64PrimTyCon :: TyCon
-int64PrimTyCon  = pcPrimTyCon0 int64PrimTyConName Int64Rep
+int64PrimTyCon  = pcPrimTyCon0 int64PrimTyConName int64RepDataConTy
 
 wordPrimTy :: Type
 wordPrimTy      = mkTyConTy wordPrimTyCon
 wordPrimTyCon :: TyCon
-wordPrimTyCon   = pcPrimTyCon0 wordPrimTyConName WordRep
+wordPrimTyCon   = pcPrimTyCon0 wordPrimTyConName wordRepDataConTy
 
 word8PrimTy :: Type
 word8PrimTy     = mkTyConTy word8PrimTyCon
 word8PrimTyCon :: TyCon
-word8PrimTyCon  = pcPrimTyCon0 word8PrimTyConName Word8Rep
+word8PrimTyCon  = pcPrimTyCon0 word8PrimTyConName word8RepDataConTy
 
 word16PrimTy :: Type
 word16PrimTy    = mkTyConTy word16PrimTyCon
 word16PrimTyCon :: TyCon
-word16PrimTyCon = pcPrimTyCon0 word16PrimTyConName Word16Rep
+word16PrimTyCon = pcPrimTyCon0 word16PrimTyConName word16RepDataConTy
 
 word32PrimTy :: Type
 word32PrimTy    = mkTyConTy word32PrimTyCon
 word32PrimTyCon :: TyCon
-word32PrimTyCon = pcPrimTyCon0 word32PrimTyConName Word32Rep
+word32PrimTyCon = pcPrimTyCon0 word32PrimTyConName word32RepDataConTy
 
 word64PrimTy :: Type
 word64PrimTy    = mkTyConTy word64PrimTyCon
 word64PrimTyCon :: TyCon
-word64PrimTyCon = pcPrimTyCon0 word64PrimTyConName Word64Rep
+word64PrimTyCon = pcPrimTyCon0 word64PrimTyConName word64RepDataConTy
 
 addrPrimTy :: Type
 addrPrimTy      = mkTyConTy addrPrimTyCon
 addrPrimTyCon :: TyCon
-addrPrimTyCon   = pcPrimTyCon0 addrPrimTyConName AddrRep
+addrPrimTyCon   = pcPrimTyCon0 addrPrimTyConName addrRepDataConTy
 
 floatPrimTy     :: Type
 floatPrimTy     = mkTyConTy floatPrimTyCon
 floatPrimTyCon :: TyCon
-floatPrimTyCon  = pcPrimTyCon0 floatPrimTyConName FloatRep
+floatPrimTyCon  = pcPrimTyCon0 floatPrimTyConName floatRepDataConTy
 
 doublePrimTy :: Type
 doublePrimTy    = mkTyConTy doublePrimTyCon
 doublePrimTyCon :: TyCon
-doublePrimTyCon = pcPrimTyCon0 doublePrimTyConName DoubleRep
+doublePrimTyCon = pcPrimTyCon0 doublePrimTyConName doubleRepDataConTy
 
 {-
 ************************************************************************
@@ -994,7 +915,7 @@ mkStatePrimTy :: Type -> Type
 mkStatePrimTy ty = TyConApp statePrimTyCon [ty]
 
 statePrimTyCon :: TyCon   -- See Note [The State# TyCon]
-statePrimTyCon   = pcPrimTyCon statePrimTyConName [Nominal] VoidRep
+statePrimTyCon   = pcPrimTyCon statePrimTyConName [Nominal] zeroBitRepTy
 
 {-
 RealWorld is deeply magical.  It is *primitive*, but it is not
@@ -1097,12 +1018,12 @@ isReflPrimTyCon =
 arrayPrimTyCon, mutableArrayPrimTyCon, mutableByteArrayPrimTyCon,
     byteArrayPrimTyCon,
     smallArrayPrimTyCon, smallMutableArrayPrimTyCon :: TyCon
-arrayPrimTyCon             = pcPrimTyCon_LevPolyLastArg arrayPrimTyConName        [Representational]          UnliftedRep
-mutableArrayPrimTyCon      = pcPrimTyCon_LevPolyLastArg mutableArrayPrimTyConName [Nominal, Representational] UnliftedRep
-mutableByteArrayPrimTyCon  = pcPrimTyCon mutableByteArrayPrimTyConName  [Nominal] UnliftedRep
-byteArrayPrimTyCon         = pcPrimTyCon0 byteArrayPrimTyConName        UnliftedRep
-smallArrayPrimTyCon        = pcPrimTyCon_LevPolyLastArg smallArrayPrimTyConName        [Representational]          UnliftedRep
-smallMutableArrayPrimTyCon = pcPrimTyCon_LevPolyLastArg smallMutableArrayPrimTyConName [Nominal, Representational] UnliftedRep
+arrayPrimTyCon             = pcPrimTyCon_LevPolyLastArg arrayPrimTyConName        [Representational]          unliftedRepTy
+mutableArrayPrimTyCon      = pcPrimTyCon_LevPolyLastArg mutableArrayPrimTyConName [Nominal, Representational] unliftedRepTy
+mutableByteArrayPrimTyCon  = pcPrimTyCon mutableByteArrayPrimTyConName  [Nominal] unliftedRepTy
+byteArrayPrimTyCon         = pcPrimTyCon0 byteArrayPrimTyConName        unliftedRepTy
+smallArrayPrimTyCon        = pcPrimTyCon_LevPolyLastArg smallArrayPrimTyConName        [Representational]          unliftedRepTy
+smallMutableArrayPrimTyCon = pcPrimTyCon_LevPolyLastArg smallMutableArrayPrimTyConName [Nominal, Representational] unliftedRepTy
 
 mkArrayPrimTy :: Type -> Type
 mkArrayPrimTy elt           = TyConApp arrayPrimTyCon [getLevity elt, elt]
@@ -1125,7 +1046,7 @@ mkSmallMutableArrayPrimTy s elt = TyConApp smallMutableArrayPrimTyCon [getLevity
 ********************************************************************* -}
 
 mutVarPrimTyCon :: TyCon
-mutVarPrimTyCon = pcPrimTyCon_LevPolyLastArg mutVarPrimTyConName [Nominal, Representational] UnliftedRep
+mutVarPrimTyCon = pcPrimTyCon_LevPolyLastArg mutVarPrimTyConName [Nominal, Representational] unliftedRepTy
 
 mkMutVarPrimTy :: Type -> Type -> Type
 mkMutVarPrimTy s elt        = TyConApp mutVarPrimTyCon [getLevity elt, s, elt]
@@ -1139,7 +1060,7 @@ mkMutVarPrimTy s elt        = TyConApp mutVarPrimTyCon [getLevity elt, s, elt]
 -}
 
 ioPortPrimTyCon :: TyCon
-ioPortPrimTyCon = pcPrimTyCon_LevPolyLastArg ioPortPrimTyConName [Nominal, Representational] UnliftedRep
+ioPortPrimTyCon = pcPrimTyCon_LevPolyLastArg ioPortPrimTyConName [Nominal, Representational] unliftedRepTy
 
 mkIOPortPrimTy :: Type -> Type -> Type
 mkIOPortPrimTy s elt          = TyConApp ioPortPrimTyCon [getLevity elt, s, elt]
@@ -1154,7 +1075,7 @@ mkIOPortPrimTy s elt          = TyConApp ioPortPrimTyCon [getLevity elt, s, elt]
 -}
 
 mVarPrimTyCon :: TyCon
-mVarPrimTyCon = pcPrimTyCon_LevPolyLastArg mVarPrimTyConName [Nominal, Representational] UnliftedRep
+mVarPrimTyCon = pcPrimTyCon_LevPolyLastArg mVarPrimTyConName [Nominal, Representational] unliftedRepTy
 
 mkMVarPrimTy :: Type -> Type -> Type
 mkMVarPrimTy s elt          = TyConApp mVarPrimTyCon [getLevity elt, s, elt]
@@ -1168,7 +1089,7 @@ mkMVarPrimTy s elt          = TyConApp mVarPrimTyCon [getLevity elt, s, elt]
 -}
 
 tVarPrimTyCon :: TyCon
-tVarPrimTyCon = pcPrimTyCon_LevPolyLastArg tVarPrimTyConName [Nominal, Representational] UnliftedRep
+tVarPrimTyCon = pcPrimTyCon_LevPolyLastArg tVarPrimTyConName [Nominal, Representational] unliftedRepTy
 
 mkTVarPrimTy :: Type -> Type -> Type
 mkTVarPrimTy s elt = TyConApp tVarPrimTyCon [getLevity elt, s, elt]
@@ -1182,7 +1103,7 @@ mkTVarPrimTy s elt = TyConApp tVarPrimTyCon [getLevity elt, s, elt]
 -}
 
 stablePtrPrimTyCon :: TyCon
-stablePtrPrimTyCon = pcPrimTyCon_LevPolyLastArg stablePtrPrimTyConName [Representational] AddrRep
+stablePtrPrimTyCon = pcPrimTyCon_LevPolyLastArg stablePtrPrimTyConName [Representational] addrRepDataConTy
 
 mkStablePtrPrimTy :: Type -> Type
 mkStablePtrPrimTy ty = TyConApp stablePtrPrimTyCon [getLevity ty, ty]
@@ -1196,7 +1117,7 @@ mkStablePtrPrimTy ty = TyConApp stablePtrPrimTyCon [getLevity ty, ty]
 -}
 
 stableNamePrimTyCon :: TyCon
-stableNamePrimTyCon = pcPrimTyCon_LevPolyLastArg stableNamePrimTyConName [Phantom] UnliftedRep
+stableNamePrimTyCon = pcPrimTyCon_LevPolyLastArg stableNamePrimTyConName [Phantom] unliftedRepTy
 
 mkStableNamePrimTy :: Type -> Type
 mkStableNamePrimTy ty = TyConApp stableNamePrimTyCon [getLevity ty, ty]
@@ -1210,7 +1131,7 @@ mkStableNamePrimTy ty = TyConApp stableNamePrimTyCon [getLevity ty, ty]
 -}
 
 compactPrimTyCon :: TyCon
-compactPrimTyCon = pcPrimTyCon0 compactPrimTyConName UnliftedRep
+compactPrimTyCon = pcPrimTyCon0 compactPrimTyConName unliftedRepTy
 
 compactPrimTy :: Type
 compactPrimTy = mkTyConTy compactPrimTyCon
@@ -1224,7 +1145,7 @@ compactPrimTy = mkTyConTy compactPrimTyCon
 -}
 
 stackSnapshotPrimTyCon :: TyCon
-stackSnapshotPrimTyCon = pcPrimTyCon0 stackSnapshotPrimTyConName UnliftedRep
+stackSnapshotPrimTyCon = pcPrimTyCon0 stackSnapshotPrimTyConName unliftedRepTy
 
 stackSnapshotPrimTy :: Type
 stackSnapshotPrimTy = mkTyConTy stackSnapshotPrimTyCon
@@ -1244,7 +1165,7 @@ stackSnapshotPrimTy = mkTyConTy stackSnapshotPrimTyCon
 bcoPrimTy    :: Type
 bcoPrimTy    = mkTyConTy bcoPrimTyCon
 bcoPrimTyCon :: TyCon
-bcoPrimTyCon = pcPrimTyCon0 bcoPrimTyConName LiftedRep
+bcoPrimTyCon = pcPrimTyCon0 bcoPrimTyConName liftedRepTy
 
 {-
 ************************************************************************
@@ -1255,7 +1176,7 @@ bcoPrimTyCon = pcPrimTyCon0 bcoPrimTyConName LiftedRep
 -}
 
 weakPrimTyCon :: TyCon
-weakPrimTyCon = pcPrimTyCon_LevPolyLastArg weakPrimTyConName [Representational] UnliftedRep
+weakPrimTyCon = pcPrimTyCon_LevPolyLastArg weakPrimTyConName [Representational] unliftedRepTy
 
 mkWeakPrimTy :: Type -> Type
 mkWeakPrimTy v = TyConApp weakPrimTyCon [getLevity v, v]
@@ -1280,7 +1201,7 @@ to the thread id internally.
 threadIdPrimTy :: Type
 threadIdPrimTy    = mkTyConTy threadIdPrimTyCon
 threadIdPrimTyCon :: TyCon
-threadIdPrimTyCon = pcPrimTyCon0 threadIdPrimTyConName UnliftedRep
+threadIdPrimTyCon = pcPrimTyCon0 threadIdPrimTyConName unliftedRepTy
 
 {-
 ************************************************************************
diff --git a/compiler/GHC/Core/TyCo/Rep.hs b/compiler/GHC/Core/TyCo/Rep.hs
index 2887977d26..391543190d 100644
--- a/compiler/GHC/Core/TyCo/Rep.hs
+++ b/compiler/GHC/Core/TyCo/Rep.hs
@@ -30,6 +30,7 @@ module GHC.Core.TyCo.Rep (
 
         TyLit(..),
         KindOrType, Kind,
+        RuntimeRepType,
         KnotTied,
         PredType, ThetaType,      -- Synonyms
         ArgFlag(..), AnonArgFlag(..),
@@ -112,6 +113,9 @@ type KindOrType = Type -- See Note [Arguments to type constructors]
 -- | The key type representing kinds in the compiler.
 type Kind = Type
 
+-- | Type synonym used for types of kind RuntimeRep.
+type RuntimeRepType = Type
+
 -- If you edit this type, you may need to update the GHC formalism
 -- See Note [GHC Formalism] in GHC.Core.Lint
 data Type
diff --git a/compiler/GHC/Types/RepType.hs b/compiler/GHC/Types/RepType.hs
index cf6517bd39..41223c625f 100644
--- a/compiler/GHC/Types/RepType.hs
+++ b/compiler/GHC/Types/RepType.hs
@@ -32,8 +32,21 @@ import GHC.Core.TyCon
 import GHC.Core.TyCon.RecWalk
 import GHC.Core.TyCo.Rep
 import GHC.Core.Type
-import GHC.Builtin.Types.Prim
-import {-# SOURCE #-} GHC.Builtin.Types ( anyTypeOfKind, runtimeRepTy )
+import {-# SOURCE #-} GHC.Builtin.Types ( anyTypeOfKind, runtimeRepTy
+  , vecRepDataConTyCon
+  , liftedRepTy, unliftedRepTy, zeroBitRepTy
+  , intRepDataConTy
+  , int8RepDataConTy, int16RepDataConTy, int32RepDataConTy, int64RepDataConTy
+  , wordRepDataConTy
+  , word16RepDataConTy, word8RepDataConTy, word32RepDataConTy, word64RepDataConTy
+  , addrRepDataConTy
+  , floatRepDataConTy, doubleRepDataConTy
+  , vec2DataConTy, vec4DataConTy, vec8DataConTy, vec16DataConTy, vec32DataConTy
+  , vec64DataConTy
+  , int8ElemRepDataConTy, int16ElemRepDataConTy, int32ElemRepDataConTy
+  , int64ElemRepDataConTy, word8ElemRepDataConTy, word16ElemRepDataConTy
+  , word32ElemRepDataConTy, word64ElemRepDataConTy, floatElemRepDataConTy
+  , doubleElemRepDataConTy )
 
 import GHC.Utils.Misc
 import GHC.Utils.Outputable
@@ -473,7 +486,8 @@ runtimeRepPrimRep works by using tyConRuntimeRepInfo. That function
 should be passed the TyCon produced by promoting one of the constructors
 of RuntimeRep into type-level data. The RuntimeRep promoted datacons are
 associated with a RuntimeRepInfo (stored directly in the PromotedDataCon
-constructor of TyCon). This pairing happens in GHC.Builtin.Types. A RuntimeRepInfo
+constructor of TyCon, field promDcRepInfo).
+This pairing happens in GHC.Builtin.Types. A RuntimeRepInfo
 usually(*) contains a function from [Type] to [PrimRep]: the [Type] are
 the arguments to the promoted datacon. These arguments are necessary
 for the TupleRep and SumRep constructors, so that this process can recur,
@@ -595,6 +609,48 @@ runtimeRepPrimRep doc rr_ty
   | otherwise
   = pprPanic "runtimeRepPrimRep" (doc $$ ppr rr_ty)
 
+-- | Convert a 'PrimRep' to a 'Type' of kind RuntimeRep
+primRepToRuntimeRep :: PrimRep -> Type
+primRepToRuntimeRep rep = case rep of
+  VoidRep       -> zeroBitRepTy
+  LiftedRep     -> liftedRepTy
+  UnliftedRep   -> unliftedRepTy
+  IntRep        -> intRepDataConTy
+  Int8Rep       -> int8RepDataConTy
+  Int16Rep      -> int16RepDataConTy
+  Int32Rep      -> int32RepDataConTy
+  Int64Rep      -> int64RepDataConTy
+  WordRep       -> wordRepDataConTy
+  Word8Rep      -> word8RepDataConTy
+  Word16Rep     -> word16RepDataConTy
+  Word32Rep     -> word32RepDataConTy
+  Word64Rep     -> word64RepDataConTy
+  AddrRep       -> addrRepDataConTy
+  FloatRep      -> floatRepDataConTy
+  DoubleRep     -> doubleRepDataConTy
+  VecRep n elem -> TyConApp vecRepDataConTyCon [n', elem']
+    where
+      n' = case n of
+        2  -> vec2DataConTy
+        4  -> vec4DataConTy
+        8  -> vec8DataConTy
+        16 -> vec16DataConTy
+        32 -> vec32DataConTy
+        64 -> vec64DataConTy
+        _  -> pprPanic "Disallowed VecCount" (ppr n)
+
+      elem' = case elem of
+        Int8ElemRep   -> int8ElemRepDataConTy
+        Int16ElemRep  -> int16ElemRepDataConTy
+        Int32ElemRep  -> int32ElemRepDataConTy
+        Int64ElemRep  -> int64ElemRepDataConTy
+        Word8ElemRep  -> word8ElemRepDataConTy
+        Word16ElemRep -> word16ElemRepDataConTy
+        Word32ElemRep -> word32ElemRepDataConTy
+        Word64ElemRep -> word64ElemRepDataConTy
+        FloatElemRep  -> floatElemRepDataConTy
+        DoubleElemRep -> doubleElemRepDataConTy
+
 -- | Convert a PrimRep back to a Type. Used only in the unariser to give types
 -- to fresh Ids. Really, only the type's representation matters.
 -- See also Note [RuntimeRep and PrimRep]
diff --git a/utils/genprimopcode/Main.hs b/utils/genprimopcode/Main.hs
index 457d519143..c4261e1e00 100644
--- a/utils/genprimopcode/Main.hs
+++ b/utils/genprimopcode/Main.hs
@@ -32,7 +32,7 @@ desugarVectorSpec i              = case vecOptions i of
                             , name    = name'
                             , prefix  = pfx
                             , veclen  = n
-                            , elemrep = con ++ "ElemRep"
+                            , elemrep = map toLower con ++ "ElemRepDataConTy"
                             , ty      = desugarTy (ty i)
                             , cat     = cat i
                             , desc    = desc i
@@ -42,7 +42,7 @@ desugarVectorSpec i              = case vecOptions i of
               PrimVecTypeSpec { ty      = desugarTy (ty i)
                               , prefix  = pfx
                               , veclen  = n
-                              , elemrep = con ++ "ElemRep"
+                              , elemrep = map toLower con ++ "ElemRepDataConTy"
                               , desc    = desc i
                               , opts    = opts i
                               }
@@ -708,7 +708,7 @@ gen_primop_vector_tys (Info _ entries)
         , ty_id ++ " = mkTyConTy " ++ tycon_id
         , tycon_id ++ " :: TyCon"
         , tycon_id ++ " = pcPrimTyCon0 " ++ name_id ++
-                      " (VecRep " ++ show (veclen i) ++ " " ++ elemrep i ++ ")"
+                      " (TyConApp vecRepDataConTyCon [vec" ++ show (veclen i) ++ "DataConTy, " ++ elemrep i ++ "])"
         ]
       where
         key_id   = prefix i ++ "PrimTyConKey"