diff --git a/compiler/types/Coercion.hs b/compiler/types/Coercion.hs
index 3a3231d2700b6675952ca0ba0ba4613380c1250b..d0c5eeda696bb602db2f34497a64a155e5411eab 100644
--- a/compiler/types/Coercion.hs
+++ b/compiler/types/Coercion.hs
@@ -169,18 +169,22 @@ Defined here to avoid module loops. CoAxiom is loaded very early on.
pprCoAxiom :: CoAxiom br -> SDoc
pprCoAxiom ax@(CoAxiom { co_ax_branches = branches })
= hang (text "axiom" <+> ppr ax <+> dcolon)
- 2 (vcat (map (ppr_co_ax_branch (const pprType) ax) $ fromBranches branches))
+ 2 (vcat (map (ppr_co_ax_branch (\_ ty -> equals <+> pprType ty) ax) $
+ fromBranches branches))
pprCoAxBranch :: CoAxiom br -> CoAxBranch -> SDoc
pprCoAxBranch = ppr_co_ax_branch pprRhs
where
pprRhs fam_tc rhs
- | Just (tycon, _) <- splitTyConApp_maybe rhs
- , isDataFamilyTyCon fam_tc
- = pprDataCons tycon
+ | isDataFamilyTyCon fam_tc
+ = empty -- Don't bother printing anything for the RHS of a data family
+ -- instance...
| otherwise
- = ppr rhs
+ = equals <+> ppr rhs
+ -- ...but for a type family instance, do print out the RHS, since
+ -- it might be needed to disambiguate between duplicate instances
+ -- (#14179)
pprCoAxBranchHdr :: CoAxiom br -> BranchIndex -> SDoc
pprCoAxBranchHdr ax index = pprCoAxBranch ax (coAxiomNthBranch ax index)
@@ -194,8 +198,8 @@ ppr_co_ax_branch ppr_rhs
, cab_rhs = rhs
, cab_loc = loc })
= foldr1 (flip hangNotEmpty 2)
- [ pprUserForAll (mkTyVarBinders Inferred (tvs ++ cvs))
- , pprTypeApp fam_tc lhs <+> equals <+> ppr_rhs fam_tc rhs
+ [ pprUserForAll (mkTyVarBinders Inferred (ee_tvs ++ cvs))
+ , pprTypeApp fam_tc ee_lhs <+> ppr_rhs fam_tc rhs
, text "-- Defined" <+> pprLoc loc ]
where
pprLoc loc
@@ -206,6 +210,21 @@ ppr_co_ax_branch ppr_rhs
= text "in" <+>
quotes (ppr (nameModule name))
+ (ee_tvs, ee_lhs)
+ | Just (tycon, tc_args) <- splitTyConApp_maybe rhs
+ , isDataFamilyTyCon fam_tc
+ = -- Eta-expand LHS types, because sometimes data family instances
+ -- are eta-reduced.
+ -- See Note [Eta reduction for data family axioms] in TcInstDecls.
+ let tc_tvs = tyConTyVars tycon
+ etad_tvs = dropList tc_args tc_tvs
+ etad_tys = mkTyVarTys etad_tvs
+ eta_expanded_tvs = tvs `chkAppend` etad_tvs
+ eta_expanded_lhs = lhs `chkAppend` etad_tys
+ in (eta_expanded_tvs, eta_expanded_lhs)
+ | otherwise
+ = (tvs, lhs)
+
{-
%************************************************************************
%* *
diff --git a/testsuite/tests/indexed-types/should_fail/Over.stderr b/testsuite/tests/indexed-types/should_fail/Over.stderr
index 63b8b304b247f41863e711f57999f07ddd36c93c..3e0bc44b576c3611bfbbdbc76cfc40856d196f05 100644
--- a/testsuite/tests/indexed-types/should_fail/Over.stderr
+++ b/testsuite/tests/indexed-types/should_fail/Over.stderr
@@ -1,8 +1,8 @@
OverB.hs:7:15: error:
Conflicting family instance declarations:
- C [Int] [a] = CListList2 -- Defined at OverB.hs:7:15
- C [a] [Int] = C9ListList -- Defined at OverC.hs:7:15
+ C [Int] [a] -- Defined at OverB.hs:7:15
+ C [a] [Int] -- Defined at OverC.hs:7:15
OverB.hs:9:15: error:
Conflicting family instance declarations:
diff --git a/testsuite/tests/indexed-types/should_fail/OverDirectThisMod.stderr b/testsuite/tests/indexed-types/should_fail/OverDirectThisMod.stderr
index 28c72df6e058fb8128ae7df7d7c3254b980e28e0..99a3377eb06116ee9108a1741046a09e4649e900 100644
--- a/testsuite/tests/indexed-types/should_fail/OverDirectThisMod.stderr
+++ b/testsuite/tests/indexed-types/should_fail/OverDirectThisMod.stderr
@@ -1,8 +1,8 @@
OverDirectThisModB.hs:7:15: error:
Conflicting family instance declarations:
- C [Int] [a] = CListList2 -- Defined at OverDirectThisModB.hs:7:15
- C [a] [Int] = C9ListList -- Defined at OverDirectThisModC.hs:10:15
+ C [Int] [a] -- Defined at OverDirectThisModB.hs:7:15
+ C [a] [Int] -- Defined at OverDirectThisModC.hs:10:15
OverDirectThisModB.hs:9:15: error:
Conflicting family instance declarations:
diff --git a/testsuite/tests/indexed-types/should_fail/OverIndirectThisMod.stderr b/testsuite/tests/indexed-types/should_fail/OverIndirectThisMod.stderr
index 53c93e80ceba254e51f5f6d392ecfe61684676fe..af136704db670a5e668b3bade85c015c2d54161d 100644
--- a/testsuite/tests/indexed-types/should_fail/OverIndirectThisMod.stderr
+++ b/testsuite/tests/indexed-types/should_fail/OverIndirectThisMod.stderr
@@ -1,10 +1,8 @@
OverIndirectThisModB.hs:7:15: error:
Conflicting family instance declarations:
- C [Int] [a] = OverIndirectThisModB.CListList2
- -- Defined at OverIndirectThisModB.hs:7:15
- C [a] [Int] = C9ListList
- -- Defined at OverIndirectThisModD.hs:11:15
+ C [Int] [a] -- Defined at OverIndirectThisModB.hs:7:15
+ C [a] [Int] -- Defined at OverIndirectThisModD.hs:11:15
OverIndirectThisModB.hs:9:15: error:
Conflicting family instance declarations:
diff --git a/testsuite/tests/indexed-types/should_fail/SimpleFail11a.stderr b/testsuite/tests/indexed-types/should_fail/SimpleFail11a.stderr
index d4670197609d3bc128d95e470a2c4460a8bc6574..41ed865dfb65888757d3736f87a7fbd2912f7152 100644
--- a/testsuite/tests/indexed-types/should_fail/SimpleFail11a.stderr
+++ b/testsuite/tests/indexed-types/should_fail/SimpleFail11a.stderr
@@ -1,10 +1,10 @@
-SimpleFail11a.hs:6:15:
+SimpleFail11a.hs:6:15: error:
Conflicting family instance declarations:
- C9 Int Int = C9IntInt -- Defined at SimpleFail11a.hs:6:15
- C9 Int Int = C9IntInt2 -- Defined at SimpleFail11a.hs:8:15
+ C9 Int Int -- Defined at SimpleFail11a.hs:6:15
+ C9 Int Int -- Defined at SimpleFail11a.hs:8:15
-SimpleFail11a.hs:11:15:
+SimpleFail11a.hs:11:15: error:
Conflicting family instance declarations:
D9 Int Int = Char -- Defined at SimpleFail11a.hs:11:15
D9 Int Int = Int -- Defined at SimpleFail11a.hs:13:15
diff --git a/testsuite/tests/indexed-types/should_fail/SimpleFail11b.stderr b/testsuite/tests/indexed-types/should_fail/SimpleFail11b.stderr
index e40a3a6b4ee6fbac542bfd1d06d35d4aceb87737..bd05039dc8de7287b9c630ff18639ef922d60b63 100644
--- a/testsuite/tests/indexed-types/should_fail/SimpleFail11b.stderr
+++ b/testsuite/tests/indexed-types/should_fail/SimpleFail11b.stderr
@@ -1,10 +1,10 @@
-SimpleFail11b.hs:7:15:
+SimpleFail11b.hs:7:15: error:
Conflicting family instance declarations:
- C9 [a] Int = C9ListInt -- Defined at SimpleFail11b.hs:7:15
- C9 [a] Int = C9ListInt2 -- Defined at SimpleFail11b.hs:9:15
+ C9 [a] Int -- Defined at SimpleFail11b.hs:7:15
+ C9 [a] Int -- Defined at SimpleFail11b.hs:9:15
-SimpleFail11b.hs:13:15:
+SimpleFail11b.hs:13:15: error:
Conflicting family instance declarations:
D9 [a] Int = [a] -- Defined at SimpleFail11b.hs:13:15
D9 [a] Int = Maybe a -- Defined at SimpleFail11b.hs:15:15
diff --git a/testsuite/tests/indexed-types/should_fail/SimpleFail11c.stderr b/testsuite/tests/indexed-types/should_fail/SimpleFail11c.stderr
index d4a1bb4f3002a7ba62c81ad65f94d33da3a1d647..cbb457933bfa018d67350e21fda7bb840ce7edc6 100644
--- a/testsuite/tests/indexed-types/should_fail/SimpleFail11c.stderr
+++ b/testsuite/tests/indexed-types/should_fail/SimpleFail11c.stderr
@@ -1,10 +1,10 @@
-SimpleFail11c.hs:7:15:
+SimpleFail11c.hs:7:15: error:
Conflicting family instance declarations:
- C9 [a] Int = C9ListInt -- Defined at SimpleFail11c.hs:7:15
- C9 [Int] Int = C9ListInt2 -- Defined at SimpleFail11c.hs:9:15
+ C9 [a] Int -- Defined at SimpleFail11c.hs:7:15
+ C9 [Int] Int -- Defined at SimpleFail11c.hs:9:15
-SimpleFail11c.hs:13:15:
+SimpleFail11c.hs:13:15: error:
Conflicting family instance declarations:
D9 [a] Int = [a] -- Defined at SimpleFail11c.hs:13:15
D9 [Int] Int = [Bool] -- Defined at SimpleFail11c.hs:15:15
diff --git a/testsuite/tests/indexed-types/should_fail/SimpleFail11d.stderr b/testsuite/tests/indexed-types/should_fail/SimpleFail11d.stderr
index cdd8afda9614e0db9e385009e85b8beca7a5056d..48d3c33fef557ef4d0e10d1d43c493e9175cff43 100644
--- a/testsuite/tests/indexed-types/should_fail/SimpleFail11d.stderr
+++ b/testsuite/tests/indexed-types/should_fail/SimpleFail11d.stderr
@@ -1,5 +1,5 @@
-SimpleFail11d.hs:8:15:
+SimpleFail11d.hs:8:15: error:
Conflicting family instance declarations:
- C9 [Int] [a] = C9ListList2 -- Defined at SimpleFail11d.hs:8:15
- C9 [a] [Int] = C9ListList -- Defined at SimpleFail11d.hs:10:15
+ C9 [Int] [a] -- Defined at SimpleFail11d.hs:8:15
+ C9 [a] [Int] -- Defined at SimpleFail11d.hs:10:15
diff --git a/testsuite/tests/indexed-types/should_fail/SimpleFail2b.stderr b/testsuite/tests/indexed-types/should_fail/SimpleFail2b.stderr
index bb0aaca16ca92fab01f27eb78599b4b843ebbca7..88fdfe127c57844686fbc0718d649449c1c5e35a 100644
--- a/testsuite/tests/indexed-types/should_fail/SimpleFail2b.stderr
+++ b/testsuite/tests/indexed-types/should_fail/SimpleFail2b.stderr
@@ -1,5 +1,5 @@
-SimpleFail2b.hs:9:11:
+SimpleFail2b.hs:9:11: error:
Conflicting family instance declarations:
- Sd Int = SdC1 Char -- Defined at SimpleFail2b.hs:9:11
- Sd Int = SdC2 Char -- Defined at SimpleFail2b.hs:10:11
+ Sd Int -- Defined at SimpleFail2b.hs:9:11
+ Sd Int -- Defined at SimpleFail2b.hs:10:11
diff --git a/testsuite/tests/indexed-types/should_fail/T14179.hs b/testsuite/tests/indexed-types/should_fail/T14179.hs
new file mode 100644
index 0000000000000000000000000000000000000000..60c8a94c393a3b20e83284cb0dacbb43de6f635c
--- /dev/null
+++ b/testsuite/tests/indexed-types/should_fail/T14179.hs
@@ -0,0 +1,20 @@
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE PolyKinds #-}
+{-# LANGUAGE TypeFamilies #-}
+module T14179 where
+
+data family Foo1 a
+data instance Foo1 a
+data instance Foo1 a
+
+data family Foo2 :: k -> *
+data instance Foo2 :: * -> *
+data instance Foo2 :: * -> *
+
+data family Foo3 a
+data instance Foo3 [a] where
+ Foo3a :: Foo3 [Int]
+ Foo3b :: Foo3 [Bool]
+data instance Foo3 [a] where
+ Foo3c :: Foo3 [a]
+ Foo3d :: Foo3 [Char]
diff --git a/testsuite/tests/indexed-types/should_fail/T14179.stderr b/testsuite/tests/indexed-types/should_fail/T14179.stderr
new file mode 100644
index 0000000000000000000000000000000000000000..38d77f1cca00ede7b3a2ab91419a5c5fcd235700
--- /dev/null
+++ b/testsuite/tests/indexed-types/should_fail/T14179.stderr
@@ -0,0 +1,15 @@
+
+T14179.hs:7:15: error:
+ Conflicting family instance declarations:
+ Foo1 a -- Defined at T14179.hs:7:15
+ Foo1 a -- Defined at T14179.hs:8:15
+
+T14179.hs:11:15: error:
+ Conflicting family instance declarations:
+ Foo2 a -- Defined at T14179.hs:11:15
+ Foo2 a -- Defined at T14179.hs:12:15
+
+T14179.hs:15:15: error:
+ Conflicting family instance declarations:
+ Foo3 [a] -- Defined at T14179.hs:15:15
+ Foo3 [a] -- Defined at T14179.hs:18:15
diff --git a/testsuite/tests/indexed-types/should_fail/T2334A.stderr b/testsuite/tests/indexed-types/should_fail/T2334A.stderr
index 7b7d265d6128a801f5b9ee25710b28203f812def..a5bc0a0e7861870681a58f1aff55509e16608226 100644
--- a/testsuite/tests/indexed-types/should_fail/T2334A.stderr
+++ b/testsuite/tests/indexed-types/should_fail/T2334A.stderr
@@ -1,17 +1,17 @@
-T2334A.hs:9:26:
- The constructor of a newtype must have exactly one field
- but ‘F’ has two
- In the definition of data constructor ‘F’
- In the newtype instance declaration for ‘F’
+T2334A.hs:9:26: error:
+ • The constructor of a newtype must have exactly one field
+ but ‘F’ has two
+ • In the definition of data constructor ‘F’
+ In the newtype instance declaration for ‘F’
-T2334A.hs:10:27:
- The constructor of a newtype must have exactly one field
- but ‘H’ has none
- In the definition of data constructor ‘H’
- In the newtype instance declaration for ‘F’
+T2334A.hs:10:27: error:
+ • The constructor of a newtype must have exactly one field
+ but ‘H’ has none
+ • In the definition of data constructor ‘H’
+ In the newtype instance declaration for ‘F’
-T2334A.hs:12:15:
+T2334A.hs:12:15: error:
Conflicting family instance declarations:
- F Bool = K1 -- Defined at T2334A.hs:12:15
- F Bool = K2 -- Defined at T2334A.hs:13:15
+ F Bool -- Defined at T2334A.hs:12:15
+ F Bool -- Defined at T2334A.hs:13:15
diff --git a/testsuite/tests/indexed-types/should_fail/T9371.stderr b/testsuite/tests/indexed-types/should_fail/T9371.stderr
index 729ee3a8c0925f3a84903350145f0fcdebd8942d..9207ac5ae2d2311eb8cda3e0a9d40dc2720cb603 100644
--- a/testsuite/tests/indexed-types/should_fail/T9371.stderr
+++ b/testsuite/tests/indexed-types/should_fail/T9371.stderr
@@ -1,5 +1,5 @@
-T9371.hs:14:10:
+T9371.hs:14:10: error:
Conflicting family instance declarations:
- D = D1 (Either x ()) -- Defined at T9371.hs:14:10
- D (x, y) = D2 (x, y) -- Defined at T9371.hs:18:10
+ D x -- Defined at T9371.hs:14:10
+ D (x, y) -- Defined at T9371.hs:18:10
diff --git a/testsuite/tests/indexed-types/should_fail/all.T b/testsuite/tests/indexed-types/should_fail/all.T
index 61025d6c928b0e2557d12ee7b50eeafcbe8bd35d..80ea5dafa9c282576af938f1002e31608833b022 100644
--- a/testsuite/tests/indexed-types/should_fail/all.T
+++ b/testsuite/tests/indexed-types/should_fail/all.T
@@ -140,5 +140,6 @@ test('T13972', normal, compile_fail, [''])
test('T14033', normal, compile_fail, [''])
test('T14045a', normal, compile_fail, [''])
test('T14175', normal, compile_fail, [''])
+test('T14179', normal, compile_fail, [''])
test('T14369', normal, compile_fail, [''])
test('T15172', normal, compile_fail, [''])
diff --git a/testsuite/tests/partial-sigs/should_compile/DataFamilyInstanceLHS.stderr b/testsuite/tests/partial-sigs/should_compile/DataFamilyInstanceLHS.stderr
index 4a94901ab52500d121b27cb9b647a8f6a8f4a590..4e0975eb3ec3e0124dc987697f7ba543abf1cea0 100644
--- a/testsuite/tests/partial-sigs/should_compile/DataFamilyInstanceLHS.stderr
+++ b/testsuite/tests/partial-sigs/should_compile/DataFamilyInstanceLHS.stderr
@@ -15,7 +15,7 @@ TYPE CONSTRUCTORS
data family Sing (a :: k)
COERCION AXIOMS
axiom DataFamilyInstanceLHS.D:R:SingMyKind_0 ::
- Sing = DataFamilyInstanceLHS.R:SingMyKind_
+ Sing _ = DataFamilyInstanceLHS.R:SingMyKind_
-- Defined at DataFamilyInstanceLHS.hs:8:15
FAMILY INSTANCES
data instance Sing
diff --git a/testsuite/tests/partial-sigs/should_compile/NamedWildcardInDataFamilyInstanceLHS.stderr b/testsuite/tests/partial-sigs/should_compile/NamedWildcardInDataFamilyInstanceLHS.stderr
index c3c383bb72a380070bac8599559443742588dd62..8fae725e61bb9697f2286eb5d5429df006a0ee41 100644
--- a/testsuite/tests/partial-sigs/should_compile/NamedWildcardInDataFamilyInstanceLHS.stderr
+++ b/testsuite/tests/partial-sigs/should_compile/NamedWildcardInDataFamilyInstanceLHS.stderr
@@ -14,7 +14,7 @@ TYPE CONSTRUCTORS
data family Sing (a :: k)
COERCION AXIOMS
axiom NamedWildcardInDataFamilyInstanceLHS.D:R:SingMyKind_a0 ::
- Sing = NamedWildcardInDataFamilyInstanceLHS.R:SingMyKind_a
+ Sing _a = NamedWildcardInDataFamilyInstanceLHS.R:SingMyKind_a
-- Defined at NamedWildcardInDataFamilyInstanceLHS.hs:8:15
FAMILY INSTANCES
data instance Sing