Introduce isBoxedTupleDataCon and use it to fix #18644wip/T18644

The code that converts promoted tuple data constructors to
`IfaceType`s in `GHC.CoreToIface` was using `isTupleDataCon`, which
conflates boxed and unboxed tuple data constructors. To avoid this,
this patch introduces `isBoxedTupleDataCon`, which is like
`isTupleDataCon` but only works for _boxed_ tuple data constructors.

While I was in town, I was horribly confused by the fact that there
were separate functions named `isUnboxedTupleCon` and
`isUnboxedTupleTyCon` (similarly, `isUnboxedSumCon` and
`isUnboxedSumTyCon`). It turns out that the former only works for
data constructors, despite its very general name! I opted to rename
`isUnboxedTupleCon` to `isUnboxedTupleDataCon` (similarly, I renamed
`isUnboxedSumCon` to `isUnboxedSumDataCon`) to avoid this potential
confusion, as well as to be more consistent with
the naming convention I used for `isBoxedTupleDataCon`.

Fixes #18644.

18 files changed, 40 insertions, 28 deletions

diff --git a/compiler/GHC/Core/DataCon.hs b/compiler/GHC/Core/DataCon.hs
index 59152b5447..9b79ae8b7f 100644
--- a/compiler/GHC/Core/DataCon.hs
+++ b/compiler/GHC/Core/DataCon.hs
@@ -51,8 +51,9 @@ module GHC.Core.DataCon (
         splitDataProductType_maybe,
 
         -- ** Predicates on DataCons
-        isNullarySrcDataCon, isNullaryRepDataCon, isTupleDataCon, isUnboxedTupleCon,
-        isUnboxedSumCon,
+        isNullarySrcDataCon, isNullaryRepDataCon,
+        isTupleDataCon, isBoxedTupleDataCon, isUnboxedTupleDataCon,
+        isUnboxedSumDataCon,
         isVanillaDataCon, classDataCon, dataConCannotMatch,
         dataConUserTyVarsArePermuted,
         isBanged, isMarkedStrict, eqHsBang, isSrcStrict, isSrcUnpacked,
@@ -1467,11 +1468,14 @@ dataConIdentity dc = LBS.toStrict $ BSB.toLazyByteString $ mconcat
 isTupleDataCon :: DataCon -> Bool
 isTupleDataCon (MkData {dcRepTyCon = tc}) = isTupleTyCon tc
 
-isUnboxedTupleCon :: DataCon -> Bool
-isUnboxedTupleCon (MkData {dcRepTyCon = tc}) = isUnboxedTupleTyCon tc
+isBoxedTupleDataCon :: DataCon -> Bool
+isBoxedTupleDataCon (MkData {dcRepTyCon = tc}) = isBoxedTupleTyCon tc
 
-isUnboxedSumCon :: DataCon -> Bool
-isUnboxedSumCon (MkData {dcRepTyCon = tc}) = isUnboxedSumTyCon tc
+isUnboxedTupleDataCon :: DataCon -> Bool
+isUnboxedTupleDataCon (MkData {dcRepTyCon = tc}) = isUnboxedTupleTyCon tc
+
+isUnboxedSumDataCon :: DataCon -> Bool
+isUnboxedSumDataCon (MkData {dcRepTyCon = tc}) = isUnboxedSumTyCon tc
 
 -- | Vanilla 'DataCon's are those that are nice boring Haskell 98 constructors
 isVanillaDataCon :: DataCon -> Bool
diff --git a/compiler/GHC/Core/DataCon.hs-boot b/compiler/GHC/Core/DataCon.hs-boot
index 6df12da9db..f8807bf3a6 100644
--- a/compiler/GHC/Core/DataCon.hs-boot
+++ b/compiler/GHC/Core/DataCon.hs-boot
@@ -26,7 +26,7 @@ dataConInstOrigArgTys  :: DataCon -> [Type] -> [Scaled Type]
 dataConStupidTheta :: DataCon -> ThetaType
 dataConFullSig :: DataCon
                -> ([TyVar], [TyCoVar], [EqSpec], ThetaType, [Scaled Type], Type)
-isUnboxedSumCon :: DataCon -> Bool
+isUnboxedSumDataCon :: DataCon -> Bool
 
 instance Eq DataCon
 instance Uniquable DataCon
diff --git a/compiler/GHC/Core/Opt/DmdAnal.hs b/compiler/GHC/Core/Opt/DmdAnal.hs
index 386a417cf9..083566ac78 100644
--- a/compiler/GHC/Core/Opt/DmdAnal.hs
+++ b/compiler/GHC/Core/Opt/DmdAnal.hs
@@ -359,7 +359,7 @@ forcesRealWorld fam_envs ty
   = True
   | Just DataConAppContext{ dcac_dc = dc, dcac_arg_tys = field_tys }
       <- deepSplitProductType_maybe fam_envs ty
-  , isUnboxedTupleCon dc
+  , isUnboxedTupleDataCon dc
   = any (\(ty,_) -> scaledThing ty `eqType` realWorldStatePrimTy) field_tys
   | otherwise
   = False
diff --git a/compiler/GHC/Core/Opt/Simplify.hs b/compiler/GHC/Core/Opt/Simplify.hs
index 4895b312db..b42e358dff 100644
--- a/compiler/GHC/Core/Opt/Simplify.hs
+++ b/compiler/GHC/Core/Opt/Simplify.hs
@@ -34,7 +34,7 @@ import GHC.Core.Coercion.Opt    ( optCoercion )
 import GHC.Core.FamInstEnv      ( topNormaliseType_maybe )
 import GHC.Core.DataCon
    ( DataCon, dataConWorkId, dataConRepStrictness
-   , dataConRepArgTys, isUnboxedTupleCon
+   , dataConRepArgTys, isUnboxedTupleDataCon
    , StrictnessMark (..) )
 import GHC.Core.Opt.Monad ( Tick(..), SimplMode(..) )
 import GHC.Core
@@ -2957,7 +2957,7 @@ addEvals :: Maybe OutExpr -> DataCon -> [Id] -> [Id]
 addEvals scrut con vs
   -- Deal with seq# applications
   | Just scr <- scrut
-  , isUnboxedTupleCon con
+  , isUnboxedTupleDataCon con
   , [s,x] <- vs
     -- Use stripNArgs rather than collectArgsTicks to avoid building
     -- a list of arguments only to throw it away immediately.
diff --git a/compiler/GHC/Core/TyCon.hs b/compiler/GHC/Core/TyCon.hs
index e1b85969e3..f4211fac5e 100644
--- a/compiler/GHC/Core/TyCon.hs
+++ b/compiler/GHC/Core/TyCon.hs
@@ -148,7 +148,7 @@ import {-# SOURCE #-} GHC.Builtin.Types
 import {-# SOURCE #-} GHC.Core.DataCon
    ( DataCon, dataConExTyCoVars, dataConFieldLabels
    , dataConTyCon, dataConFullSig
-   , isUnboxedSumCon )
+   , isUnboxedSumDataCon )
 import GHC.Builtin.Uniques
   ( tyConRepNameUnique
   , dataConTyRepNameUnique )
@@ -1323,7 +1323,7 @@ tyConRepName_maybe (AlgTyCon { algTcParent = parent })
 tyConRepName_maybe (FamilyTyCon { famTcFlav = DataFamilyTyCon rep_nm })
   = Just rep_nm
 tyConRepName_maybe (PromotedDataCon { dataCon = dc, tcRepName = rep_nm })
-  | isUnboxedSumCon dc   -- see #13276
+  | isUnboxedSumDataCon dc   -- see #13276
   = Nothing
   | otherwise
   = Just rep_nm
diff --git a/compiler/GHC/Core/Unfold.hs b/compiler/GHC/Core/Unfold.hs
index 4792545df7..ea778f5a2d 100644
--- a/compiler/GHC/Core/Unfold.hs
+++ b/compiler/GHC/Core/Unfold.hs
@@ -889,7 +889,7 @@ conSize dc n_val_args
   | n_val_args == 0 = SizeIs 0 emptyBag 10    -- Like variables
 
 -- See Note [Unboxed tuple size and result discount]
-  | isUnboxedTupleCon dc = SizeIs 0 emptyBag 10
+  | isUnboxedTupleDataCon dc = SizeIs 0 emptyBag 10
 
 -- See Note [Constructor size and result discount]
   | otherwise = SizeIs 10 emptyBag 10
diff --git a/compiler/GHC/CoreToByteCode.hs b/compiler/GHC/CoreToByteCode.hs
index 239152c059..051abd4d8b 100644
--- a/compiler/GHC/CoreToByteCode.hs
+++ b/compiler/GHC/CoreToByteCode.hs
@@ -648,7 +648,7 @@ schemeE d s p (AnnCase (_,scrut) _ _ []) = schemeE d s p scrut
 
 -- handle pairs with one void argument (e.g. state token)
 schemeE d s p (AnnCase scrut bndr _ [(DataAlt dc, [bind1, bind2], rhs)])
-   | isUnboxedTupleCon dc
+   | isUnboxedTupleDataCon dc
         -- Convert
         --      case .... of x { (# V'd-thing, a #) -> ... }
         -- to
@@ -667,7 +667,7 @@ schemeE d s p (AnnCase scrut bndr _ [(DataAlt dc, [bind1, bind2], rhs)])
 
 -- handle unit tuples
 schemeE d s p (AnnCase scrut bndr _ [(DataAlt dc, [bind1], rhs)])
-   | isUnboxedTupleCon dc
+   | isUnboxedTupleDataCon dc
    , typePrimRep (idType bndr) `lengthAtMost` 1
    = doCase d s p scrut bind1 [(DEFAULT, [], rhs)] (Just bndr)
 
@@ -825,7 +825,7 @@ schemeT d s p app
 
    -- Case 2: Constructor application
    | Just con <- maybe_saturated_dcon
-   , isUnboxedTupleCon con
+   , isUnboxedTupleDataCon con
    = case args_r_to_l of
         [arg1,arg2] | isVAtom arg1 ->
                   unboxedTupleReturn d s p arg2
@@ -1090,7 +1090,7 @@ doCase d s p (_,scrut) bndr alts is_unboxed_tuple
 
         my_discr (DEFAULT, _, _) = NoDiscr {-shouldn't really happen-}
         my_discr (DataAlt dc, _, _)
-           | isUnboxedTupleCon dc || isUnboxedSumCon dc
+           | isUnboxedTupleDataCon dc || isUnboxedSumDataCon dc
            = multiValException
            | otherwise
            = DiscrP (fromIntegral (dataConTag dc - fIRST_TAG))
diff --git a/compiler/GHC/CoreToIface.hs b/compiler/GHC/CoreToIface.hs
index f9a11fe716..a65e89853c 100644
--- a/compiler/GHC/CoreToIface.hs
+++ b/compiler/GHC/CoreToIface.hs
@@ -188,7 +188,7 @@ toIfaceTypeX fr (TyConApp tc tys)
   = IfaceTupleTy sort NotPromoted (toIfaceTcArgsX fr tc tys)
 
   | Just dc <- isPromotedDataCon_maybe tc
-  , isTupleDataCon dc
+  , isBoxedTupleDataCon dc
   , n_tys == 2*arity
   = IfaceTupleTy BoxedTuple IsPromoted (toIfaceTcArgsX fr tc (drop arity tys))
 
diff --git a/compiler/GHC/CoreToStg.hs b/compiler/GHC/CoreToStg.hs
index 1abeb56fb7..2361a041d3 100644
--- a/compiler/GHC/CoreToStg.hs
+++ b/compiler/GHC/CoreToStg.hs
@@ -699,7 +699,7 @@ mkTopStgRhs dflags this_mod ccs bndr rhs
   , -- Dynamic StgConApps are updatable
     not (isDllConApp dflags this_mod con args)
   = -- CorePrep does this right, but just to make sure
-    ASSERT2( not (isUnboxedTupleCon con || isUnboxedSumCon con)
+    ASSERT2( not (isUnboxedTupleDataCon con || isUnboxedSumDataCon con)
            , ppr bndr $$ ppr con $$ ppr args)
     ( StgRhsCon dontCareCCS con args, ccs )
 
diff --git a/compiler/GHC/HsToCore/PmCheck/Ppr.hs b/compiler/GHC/HsToCore/PmCheck/Ppr.hs
index 99ec5de4af..dc1739908f 100644
--- a/compiler/GHC/HsToCore/PmCheck/Ppr.hs
+++ b/compiler/GHC/HsToCore/PmCheck/Ppr.hs
@@ -172,7 +172,7 @@ pprConLike delta _prec cl args
       WcVarTerminated pref x ->
         parens   . fcat . punctuate colon <$> mapM (pprPmVar appPrec) (toList pref ++ [x])
 pprConLike _delta _prec (RealDataCon con) args
-  | isUnboxedTupleCon con
+  | isUnboxedTupleDataCon con
   , let hash_parens doc = text "(#" <+> doc <+> text "#)"
   = hash_parens . fsep . punctuate comma <$> mapM (pprPmVar appPrec) args
   | isTupleDataCon con
diff --git a/compiler/GHC/Stg/Lint.hs b/compiler/GHC/Stg/Lint.hs
index 206dd39187..2ce2c9b4d1 100644
--- a/compiler/GHC/Stg/Lint.hs
+++ b/compiler/GHC/Stg/Lint.hs
@@ -164,7 +164,7 @@ lintStgRhs (StgRhsClosure _ _ _ binders expr)
         lintStgExpr expr
 
 lintStgRhs rhs@(StgRhsCon _ con args) = do
-    when (isUnboxedTupleCon con || isUnboxedSumCon con) $ do
+    when (isUnboxedTupleDataCon con || isUnboxedSumDataCon con) $ do
       opts <- getStgPprOpts
       addErrL (text "StgRhsCon is an unboxed tuple or sum application" $$
                pprStgRhs opts rhs)
@@ -182,7 +182,7 @@ lintStgExpr (StgApp fun args) = do
 lintStgExpr app@(StgConApp con args _arg_tys) = do
     -- unboxed sums should vanish during unarise
     lf <- getLintFlags
-    when (lf_unarised lf && isUnboxedSumCon con) $ do
+    when (lf_unarised lf && isUnboxedSumDataCon con) $ do
       opts <- getStgPprOpts
       addErrL (text "Unboxed sum after unarise:" $$
                pprStgExpr opts app)
diff --git a/compiler/GHC/Stg/Unarise.hs b/compiler/GHC/Stg/Unarise.hs
index 85c022f799..084c797136 100644
--- a/compiler/GHC/Stg/Unarise.hs
+++ b/compiler/GHC/Stg/Unarise.hs
@@ -294,7 +294,7 @@ unariseRhs rho (StgRhsClosure ext ccs update_flag args expr)
        return (StgRhsClosure ext ccs update_flag args1 expr')
 
 unariseRhs rho (StgRhsCon ccs con args)
-  = ASSERT(not (isUnboxedTupleCon con || isUnboxedSumCon con))
+  = ASSERT(not (isUnboxedTupleDataCon con || isUnboxedSumDataCon con))
     return (StgRhsCon ccs con (unariseConArgs rho args))
 
 --------------------------------------------------------------------------------
@@ -372,10 +372,10 @@ unariseExpr rho (StgTick tick e)
 -- Doesn't return void args.
 unariseMulti_maybe :: UnariseEnv -> DataCon -> [InStgArg] -> [Type] -> Maybe [OutStgArg]
 unariseMulti_maybe rho dc args ty_args
-  | isUnboxedTupleCon dc
+  | isUnboxedTupleDataCon dc
   = Just (unariseConArgs rho args)
 
-  | isUnboxedSumCon dc
+  | isUnboxedSumDataCon dc
   , let args1 = ASSERT(isSingleton args) (unariseConArgs rho args)
   = Just (mkUbxSum dc ty_args args1)
 
diff --git a/compiler/GHC/StgToCmm/DataCon.hs b/compiler/GHC/StgToCmm/DataCon.hs
index 8e11bffad3..681f1461f1 100644
--- a/compiler/GHC/StgToCmm/DataCon.hs
+++ b/compiler/GHC/StgToCmm/DataCon.hs
@@ -354,7 +354,7 @@ bindConArgs :: AltCon -> LocalReg -> [NonVoid Id] -> FCode [LocalReg]
 -- binders args, assuming that we have just returned from a 'case' which
 -- found a con
 bindConArgs (DataAlt con) base args
-  = ASSERT(not (isUnboxedTupleCon con))
+  = ASSERT(not (isUnboxedTupleDataCon con))
     do profile <- getProfile
        platform <- getPlatform
        let (_, _, args_w_offsets) = mkVirtConstrOffsets profile (addIdReps args)
diff --git a/compiler/GHC/StgToCmm/Expr.hs b/compiler/GHC/StgToCmm/Expr.hs
index 72f8941740..f6c8176a92 100644
--- a/compiler/GHC/StgToCmm/Expr.hs
+++ b/compiler/GHC/StgToCmm/Expr.hs
@@ -837,7 +837,7 @@ maybeAltHeapCheck (GcInAlts regs, ReturnedTo lret off) code =
 
 cgConApp :: DataCon -> [StgArg] -> FCode ReturnKind
 cgConApp con stg_args
-  | isUnboxedTupleCon con       -- Unboxed tuple: assign and return
+  | isUnboxedTupleDataCon con       -- Unboxed tuple: assign and return
   = do { arg_exprs <- getNonVoidArgAmodes stg_args
        ; tickyUnboxedTupleReturn (length arg_exprs)
        ; emitReturn arg_exprs }
diff --git a/compiler/GHC/Types/Id.hs b/compiler/GHC/Types/Id.hs
index 5b6c54cc00..2d6198dd64 100644
--- a/compiler/GHC/Types/Id.hs
+++ b/compiler/GHC/Types/Id.hs
@@ -556,7 +556,7 @@ hasNoBinding :: Id -> Bool
 hasNoBinding id = case Var.idDetails id of
                         PrimOpId _       -> True    -- See Note [Eta expanding primops] in GHC.Builtin.PrimOps
                         FCallId _        -> True
-                        DataConWorkId dc -> isUnboxedTupleCon dc || isUnboxedSumCon dc
+                        DataConWorkId dc -> isUnboxedTupleDataCon dc || isUnboxedSumDataCon dc
                         _                -> isCompulsoryUnfolding (idUnfolding id)
                                             -- See Note [Levity-polymorphic Ids]
 
diff --git a/testsuite/tests/ghci/scripts/T18644.script b/testsuite/tests/ghci/scripts/T18644.script
new file mode 100644
index 0000000000..e1fb4a86d8
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/T18644.script
@@ -0,0 +1,3 @@
+:set -XDataKinds -XUnboxedTuples
+:kind! '(# #)
+:kind! '()
diff --git a/testsuite/tests/ghci/scripts/T18644.stdout b/testsuite/tests/ghci/scripts/T18644.stdout
new file mode 100644
index 0000000000..704d4344b4
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/T18644.stdout
@@ -0,0 +1,4 @@
+'(# #) :: (# #)
+= '(# #)
+'() :: ()
+= '()
diff --git a/testsuite/tests/ghci/scripts/all.T b/testsuite/tests/ghci/scripts/all.T
index 0a05e1dffa..e9d40a7d68 100755
--- a/testsuite/tests/ghci/scripts/all.T
+++ b/testsuite/tests/ghci/scripts/all.T
@@ -315,3 +315,4 @@ test('T17403', normal, ghci_script, ['T17403.script'])
 test('T17431', normal, ghci_script, ['T17431.script'])
 test('T17549', normal, ghci_script, ['T17549.script'])
 test('T17669', [extra_run_opts('-fexternal-interpreter -fobject-code'), expect_broken(17669)], ghci_script, ['T17669.script'])
+test('T18644', normal, ghci_script, ['T18644.script'])