Updates to support closed type families.

54 files changed, 240 insertions, 319 deletions

diff --git a/testsuite/tests/ghci/scripts/T4175.hs b/testsuite/tests/ghci/scripts/T4175.hs
index 69ff79fd94..a3b1d273f5 100644
--- a/testsuite/tests/ghci/scripts/T4175.hs
+++ b/testsuite/tests/ghci/scripts/T4175.hs
@@ -17,8 +17,6 @@ instance C Int where
 instance C () where
     type D () () = Bool
 
-type family E a
-
-type instance where
+type family E a where
     E ()  = Bool
     E Int = String
\ No newline at end of file
diff --git a/testsuite/tests/ghci/scripts/T4175.stdout b/testsuite/tests/ghci/scripts/T4175.stdout
index bfbfc87765..553d92a0ab 100644
--- a/testsuite/tests/ghci/scripts/T4175.stdout
+++ b/testsuite/tests/ghci/scripts/T4175.stdout
@@ -1,52 +1,46 @@
-type family A a b :: * 	-- Defined at T4175.hs:4:13

-type instance A (Maybe a) a -- Defined at T4175.hs:6:15

-type instance A Int Int -- Defined at T4175.hs:5:15

-data family B a 	-- Defined at T4175.hs:8:13

-data instance B () -- Defined at T4175.hs:9:15

-class C a where

-  type family D a b :: *

-  	-- Defined at T4175.hs:12:10

-type D () () -- Defined at T4175.hs:18:10

-type D Int () -- Defined at T4175.hs:15:10

-type family E a :: * 	-- Defined at T4175.hs:20:13

-type instance where

-  E () -- Defined at T4175.hs:23:5

-  E Int -- Defined at T4175.hs:24:5

-data () = () 	-- Defined in ‛GHC.Tuple’

-instance C () -- Defined at T4175.hs:17:10

-instance Bounded () -- Defined in ‛GHC.Enum’

-instance Enum () -- Defined in ‛GHC.Enum’

-instance Eq () -- Defined in ‛GHC.Classes’

-instance Ord () -- Defined in ‛GHC.Classes’

-instance Read () -- Defined in ‛GHC.Read’

-instance Show () -- Defined in ‛GHC.Show’

-type instance where

-  E () -- Defined at T4175.hs:23:5

-  E Int -- Defined at T4175.hs:24:5

-type D () () -- Defined at T4175.hs:18:10

-type D Int () -- Defined at T4175.hs:15:10

-data instance B () -- Defined at T4175.hs:9:15

-data Maybe a = Nothing | Just a 	-- Defined in ‛Data.Maybe’

-instance Eq a => Eq (Maybe a) -- Defined in ‛Data.Maybe’

-instance Monad Maybe -- Defined in ‛Data.Maybe’

-instance Functor Maybe -- Defined in ‛Data.Maybe’

-instance Ord a => Ord (Maybe a) -- Defined in ‛Data.Maybe’

-instance Read a => Read (Maybe a) -- Defined in ‛GHC.Read’

-instance Show a => Show (Maybe a) -- Defined in ‛GHC.Show’

-type instance A (Maybe a) a -- Defined at T4175.hs:6:15

-data Int = GHC.Types.I# GHC.Prim.Int# 	-- Defined in ‛GHC.Types’

-instance C Int -- Defined at T4175.hs:14:10

-instance Bounded Int -- Defined in ‛GHC.Enum’

-instance Enum Int -- Defined in ‛GHC.Enum’

-instance Eq Int -- Defined in ‛GHC.Classes’

-instance Integral Int -- Defined in ‛GHC.Real’

-instance Num Int -- Defined in ‛GHC.Num’

-instance Ord Int -- Defined in ‛GHC.Classes’

-instance Read Int -- Defined in ‛GHC.Read’

-instance Real Int -- Defined in ‛GHC.Real’

-instance Show Int -- Defined in ‛GHC.Show’

-type instance where

-  E () -- Defined at T4175.hs:23:5

-  E Int -- Defined at T4175.hs:24:5

-type D Int () -- Defined at T4175.hs:15:10

-type instance A Int Int -- Defined at T4175.hs:5:15

+type family A a b :: * 	-- Defined at T4175.hs:4:13
+type instance A (Maybe a) a -- Defined at T4175.hs:6:1
+type instance A Int Int -- Defined at T4175.hs:5:1
+data family B a 	-- Defined at T4175.hs:8:13
+data instance B () -- Defined at T4175.hs:9:15
+class C a where
+  type family D a b :: *
+  	-- Defined at T4175.hs:12:10
+type D () () -- Defined at T4175.hs:18:5
+type D Int () -- Defined at T4175.hs:15:5
+type family E a :: * where
+    E () = Bool
+    E Int = String
+  	-- Defined at T4175.hs:20:13
+data () = () 	-- Defined in ‛GHC.Tuple’
+instance C () -- Defined at T4175.hs:17:10
+instance Bounded () -- Defined in ‛GHC.Enum’
+instance Enum () -- Defined in ‛GHC.Enum’
+instance Eq () -- Defined in ‛GHC.Classes’
+instance Ord () -- Defined in ‛GHC.Classes’
+instance Read () -- Defined in ‛GHC.Read’
+instance Show () -- Defined in ‛GHC.Show’
+type D () () -- Defined at T4175.hs:18:5
+type D Int () -- Defined at T4175.hs:15:5
+data instance B () -- Defined at T4175.hs:9:15
+data Maybe a = Nothing | Just a 	-- Defined in ‛Data.Maybe’
+instance Eq a => Eq (Maybe a) -- Defined in ‛Data.Maybe’
+instance Monad Maybe -- Defined in ‛Data.Maybe’
+instance Functor Maybe -- Defined in ‛Data.Maybe’
+instance Ord a => Ord (Maybe a) -- Defined in ‛Data.Maybe’
+instance Read a => Read (Maybe a) -- Defined in ‛GHC.Read’
+instance Show a => Show (Maybe a) -- Defined in ‛GHC.Show’
+type instance A (Maybe a) a -- Defined at T4175.hs:6:1
+data Int = GHC.Types.I# GHC.Prim.Int# 	-- Defined in ‛GHC.Types’
+instance C Int -- Defined at T4175.hs:14:10
+instance Bounded Int -- Defined in ‛GHC.Enum’
+instance Enum Int -- Defined in ‛GHC.Enum’
+instance Eq Int -- Defined in ‛GHC.Classes’
+instance Integral Int -- Defined in ‛GHC.Real’
+instance Num Int -- Defined in ‛GHC.Num’
+instance Ord Int -- Defined in ‛GHC.Classes’
+instance Read Int -- Defined in ‛GHC.Read’
+instance Real Int -- Defined in ‛GHC.Real’
+instance Show Int -- Defined in ‛GHC.Show’
+type D Int () -- Defined at T4175.hs:15:5
+type instance A Int Int -- Defined at T4175.hs:5:1
diff --git a/testsuite/tests/indexed-types/should_compile/Overlap1.hs b/testsuite/tests/indexed-types/should_compile/Overlap1.hs
index b285deece1..4ee3776f59 100644
--- a/testsuite/tests/indexed-types/should_compile/Overlap1.hs
+++ b/testsuite/tests/indexed-types/should_compile/Overlap1.hs
@@ -2,8 +2,7 @@
 
 module Overlap1 where
 
-type family F a
-type instance where
+type family F a where
   F Int = Int
   F a = Bool
 
diff --git a/testsuite/tests/indexed-types/should_compile/Overlap12.hs b/testsuite/tests/indexed-types/should_compile/Overlap12.hs
index 414c9d9f03..6fe1bd981c 100644
--- a/testsuite/tests/indexed-types/should_compile/Overlap12.hs
+++ b/testsuite/tests/indexed-types/should_compile/Overlap12.hs
@@ -2,8 +2,7 @@
 
 module Overlap12 where
 
-type family And (a :: Bool) (b :: Bool) :: Bool
-type instance where
+type family And (a :: Bool) (b :: Bool) :: Bool where
   And False x = False
   And True x = x
   And x False = False
@@ -12,5 +11,17 @@ type instance where
 
 data Proxy p = P
 
-i :: Proxy (And False x)
-i = (P :: Proxy False)
\ No newline at end of file
+a :: Proxy (And False x)
+a = (P :: Proxy False)
+
+b :: Proxy x -> Proxy (And True x)
+b x = x
+
+c :: Proxy (And x False)
+c = (P :: Proxy False)
+
+d :: Proxy x -> Proxy (And x True)
+d x = x
+
+e :: Proxy x -> Proxy (And x x)
+e x = x
diff --git a/testsuite/tests/indexed-types/should_compile/Overlap13.hs b/testsuite/tests/indexed-types/should_compile/Overlap13.hs
new file mode 100644
index 0000000000..56fc78e3a1
--- /dev/null
+++ b/testsuite/tests/indexed-types/should_compile/Overlap13.hs
@@ -0,0 +1,15 @@
+{-# LANGUAGE TypeFamilies #-}
+
+module Overlap13 where
+
+type family F a b where
+  F a a = Int
+  F a Int = Int
+  F a b = b
+
+g :: a -> F a Int
+g x = (5 :: Int)
+
+
+
+
diff --git a/testsuite/tests/indexed-types/should_compile/Overlap14.hs b/testsuite/tests/indexed-types/should_compile/Overlap14.hs
new file mode 100644
index 0000000000..49af37c8bd
--- /dev/null
+++ b/testsuite/tests/indexed-types/should_compile/Overlap14.hs
@@ -0,0 +1,12 @@
+{-# LANGUAGE TypeFamilies #-}
+
+module Overlap14 where
+
+type family F a b c where
+  F a a a   = Int
+  F Int b c = Bool
+
+type family G x
+
+foo :: F Int (G Bool) Bool
+foo = False
diff --git a/testsuite/tests/indexed-types/should_compile/Overlap2.hs b/testsuite/tests/indexed-types/should_compile/Overlap2.hs
index ced2dd4292..3a4da42c00 100644
--- a/testsuite/tests/indexed-types/should_compile/Overlap2.hs
+++ b/testsuite/tests/indexed-types/should_compile/Overlap2.hs
@@ -2,8 +2,7 @@
 
 module Overlap2 where
 
-type family F a b
-type instance where
+type family F a b where
   F a a = Int
   F a b = Bool
 
diff --git a/testsuite/tests/indexed-types/should_compile/T3017.stderr b/testsuite/tests/indexed-types/should_compile/T3017.stderr
index a6b44e3ad5..5c6a2641c7 100644
--- a/testsuite/tests/indexed-types/should_compile/T3017.stderr
+++ b/testsuite/tests/indexed-types/should_compile/T3017.stderr
@@ -1,24 +1,24 @@
-TYPE SIGNATURES

-  emptyL :: forall a. ListColl a

-  test2 ::

-    forall c t t1. (Num t, Num t1, Coll c, Elem c ~ (t, t1)) => c -> c

-TYPE CONSTRUCTORS

-  Coll :: * -> Constraint

-  class Coll c

-      RecFlag NonRecursive

-      type family Elem c :: *

-      empty :: c insert :: Elem c -> c -> c

-  ListColl :: * -> *

-  data ListColl a

-      No C type associated

-      RecFlag NonRecursive, Promotable

-      = L :: forall a. [a] -> ListColl a Stricts: _

-      FamilyInstance: none

-COERCION AXIOMS

-  axiom Foo.TFCo:R:ElemListColl :: Elem (ListColl a) = a

-INSTANCES

-  instance Coll (ListColl a) -- Defined at T3017.hs:12:11

-FAMILY INSTANCES

-  type Elem (ListColl a) -- Defined at T3017.hs:13:9

-Dependent modules: []

-Dependent packages: [base, ghc-prim, integer-gmp]

+TYPE SIGNATURES
+  emptyL :: forall a. ListColl a
+  test2 ::
+    forall c t t1. (Num t, Num t1, Coll c, Elem c ~ (t, t1)) => c -> c
+TYPE CONSTRUCTORS
+  Coll :: * -> Constraint
+  class Coll c
+      RecFlag NonRecursive
+      type family Elem c :: *
+      empty :: c insert :: Elem c -> c -> c
+  ListColl :: * -> *
+  data ListColl a
+      No C type associated
+      RecFlag NonRecursive, Promotable
+      = L :: forall a. [a] -> ListColl a Stricts: _
+      FamilyInstance: none
+COERCION AXIOMS
+  axiom Foo.TFCo:R:ElemListColl :: Elem (ListColl a) = a
+INSTANCES
+  instance Coll (ListColl a) -- Defined at T3017.hs:12:11
+FAMILY INSTANCES
+  type Elem (ListColl a) -- Defined at T3017.hs:13:4
+Dependent modules: []
+Dependent packages: [base, ghc-prim, integer-gmp]
diff --git a/testsuite/tests/indexed-types/should_compile/T7585.hs b/testsuite/tests/indexed-types/should_compile/T7585.hs
index 475269c851..93a85b6b6f 100644
--- a/testsuite/tests/indexed-types/should_compile/T7585.hs
+++ b/testsuite/tests/indexed-types/should_compile/T7585.hs
@@ -11,8 +11,7 @@ data SList :: [Bool] -> * where
   SNil :: SList '[]
   SCons :: SBool h -> SList t -> SList (h ': t)
 
-type family (a :: k) :==: (b :: k) :: Bool
-type instance where
+type family (a :: k) :==: (b :: k) :: Bool where
   '[] :==: '[] = True
   (h1 ': t1) :==: (h2 ': t2) = True
   a :==: b = False
diff --git a/testsuite/tests/indexed-types/should_compile/all.T b/testsuite/tests/indexed-types/should_compile/all.T
index ac3a5f866d..419008cc88 100644
--- a/testsuite/tests/indexed-types/should_compile/all.T
+++ b/testsuite/tests/indexed-types/should_compile/all.T
@@ -200,6 +200,8 @@ test('T7082', normal, compile, [''])
 test('Overlap1', normal, compile, [''])
 test('Overlap2', normal, compile, [''])
 test('Overlap12', normal, compile, [''])
+test('Overlap13', normal, compile, [''])
+test('Overlap14', normal, compile, [''])
 test('T7156', normal, compile, [''])
 test('T5591a', normal, compile, [''])
 test('T5591b', normal, compile, [''])
diff --git a/testsuite/tests/indexed-types/should_fail/NoGood.hs b/testsuite/tests/indexed-types/should_fail/NoGood.hs
new file mode 100644
index 0000000000..43a237b0ff
--- /dev/null
+++ b/testsuite/tests/indexed-types/should_fail/NoGood.hs
@@ -0,0 +1,5 @@
+{-# LANGUAGE TypeFamilies #-}
+
+type family F a b
+type instance F a a = Int
+type instance F [a] a = Bool
diff --git a/testsuite/tests/indexed-types/should_fail/NoGood.stderr b/testsuite/tests/indexed-types/should_fail/NoGood.stderr
new file mode 100644
index 0000000000..bfb5814f8d
--- /dev/null
+++ b/testsuite/tests/indexed-types/should_fail/NoGood.stderr
@@ -0,0 +1,5 @@
+
+NoGood.hs:4:15:
+    Conflicting family instance declarations:
+      F a a -- Defined at NoGood.hs:4:15
+      F [a] a -- Defined at NoGood.hs:5:15
diff --git a/testsuite/tests/indexed-types/should_fail/Overlap10.hs b/testsuite/tests/indexed-types/should_fail/Overlap10.hs
index 07a13e0219..c99839bc93 100644
--- a/testsuite/tests/indexed-types/should_fail/Overlap10.hs
+++ b/testsuite/tests/indexed-types/should_fail/Overlap10.hs
@@ -2,8 +2,7 @@
 
 module Overlap10 where
 
-type family F a b
-type instance where
+type family F a b where
   F a a = Int
   F a b = b
 
diff --git a/testsuite/tests/indexed-types/should_fail/Overlap10.stderr b/testsuite/tests/indexed-types/should_fail/Overlap10.stderr
index 342cbe4bca..b31de8d757 100644
--- a/testsuite/tests/indexed-types/should_fail/Overlap10.stderr
+++ b/testsuite/tests/indexed-types/should_fail/Overlap10.stderr
@@ -1,8 +1,8 @@
 
-Overlap10.hs:11:7:
+Overlap10.hs:10:7:
     Couldn't match expected type ‛F a Bool’ with actual type ‛Bool’
     Relevant bindings include
-      g :: a -> F a Bool (bound at Overlap10.hs:11:1)
-      x :: a (bound at Overlap10.hs:11:3)
+      g :: a -> F a Bool (bound at Overlap10.hs:10:1)
+      x :: a (bound at Overlap10.hs:10:3)
     In the expression: False
     In an equation for ‛g’: g x = False
diff --git a/testsuite/tests/indexed-types/should_fail/Overlap11.hs b/testsuite/tests/indexed-types/should_fail/Overlap11.hs
index 1498d5946a..79b0ecba60 100644
--- a/testsuite/tests/indexed-types/should_fail/Overlap11.hs
+++ b/testsuite/tests/indexed-types/should_fail/Overlap11.hs
@@ -2,8 +2,7 @@
 
 module Overlap11 where
 
-type family F a b
-type instance where
+type family F a b where
   F a a = Int
   F a b = b
 
diff --git a/testsuite/tests/indexed-types/should_fail/Overlap11.stderr b/testsuite/tests/indexed-types/should_fail/Overlap11.stderr
index 476ae6c2fb..97627e7939 100644
--- a/testsuite/tests/indexed-types/should_fail/Overlap11.stderr
+++ b/testsuite/tests/indexed-types/should_fail/Overlap11.stderr
@@ -1,8 +1,8 @@
 
-Overlap11.hs:11:8:
+Overlap11.hs:10:8:
     Couldn't match expected type ‛F a Int’ with actual type ‛Int’
     Relevant bindings include
-      g :: a -> F a Int (bound at Overlap11.hs:11:1)
-      x :: a (bound at Overlap11.hs:11:3)
+      g :: a -> F a Int (bound at Overlap11.hs:10:1)
+      x :: a (bound at Overlap11.hs:10:3)
     In the expression: (5 :: Int)
     In an equation for ‛g’: g x = (5 :: Int)
diff --git a/testsuite/tests/indexed-types/should_fail/Overlap3.hs b/testsuite/tests/indexed-types/should_fail/Overlap3.hs
index 654d626904..82837d9193 100644
--- a/testsuite/tests/indexed-types/should_fail/Overlap3.hs
+++ b/testsuite/tests/indexed-types/should_fail/Overlap3.hs
@@ -2,8 +2,7 @@
 
 module Overlap3 where
 
-type family F a b
-type instance where
+type family F a b where
   F a a = Int
   F a b = Bool
 type instance F Char Char = Int
diff --git a/testsuite/tests/indexed-types/should_fail/Overlap3.stderr b/testsuite/tests/indexed-types/should_fail/Overlap3.stderr
index 7226058e12..c8d1b5ef80 100644
--- a/testsuite/tests/indexed-types/should_fail/Overlap3.stderr
+++ b/testsuite/tests/indexed-types/should_fail/Overlap3.stderr
@@ -1,10 +1,4 @@
 
-Overlap3.hs:7:3:
-    Conflicting family instance declarations:
-      F a a -- Defined at Overlap3.hs:7:3
-      F Char Char -- Defined at Overlap3.hs:9:15
-
-Overlap3.hs:8:3:
-    Conflicting family instance declarations:
-      F a b -- Defined at Overlap3.hs:8:3
-      F Char Char -- Defined at Overlap3.hs:9:15
+Overlap3.hs:8:1:
+    Illegal instance for closed family ‛F’
+    In the type instance declaration for ‛F’
diff --git a/testsuite/tests/indexed-types/should_fail/Overlap4.hs b/testsuite/tests/indexed-types/should_fail/Overlap4.hs
index 4f1b872b9e..3399c614b8 100644
--- a/testsuite/tests/indexed-types/should_fail/Overlap4.hs
+++ b/testsuite/tests/indexed-types/should_fail/Overlap4.hs
@@ -2,15 +2,7 @@
 
 module Overlap4 where
 
-type family F a b
-type instance F Char Char = Int
-type instance where
-  F a a = Int
-  F a b = Bool
+type family F a b where
+  F Int Int = Bool
+  F Bool = Maybe
 
-
-g :: F Char Double
-g = False
-
-h :: F Double Double
-h = -2
diff --git a/testsuite/tests/indexed-types/should_fail/Overlap4.stderr b/testsuite/tests/indexed-types/should_fail/Overlap4.stderr
index fd97e97481..fd545b6334 100644
--- a/testsuite/tests/indexed-types/should_fail/Overlap4.stderr
+++ b/testsuite/tests/indexed-types/should_fail/Overlap4.stderr
@@ -1,5 +1,5 @@
 
-Overlap4.hs:6:15:
-    Conflicting family instance declarations:
-      F Char Char -- Defined at Overlap4.hs:6:15
-      F a a -- Defined at Overlap4.hs:8:3
+Overlap4.hs:7:3:
+    Number of parameters must match family declaration; expected 2
+    In the equations for closed type family ‛F’
+    In the family declaration for ‛F’
diff --git a/testsuite/tests/indexed-types/should_fail/Overlap5.hs b/testsuite/tests/indexed-types/should_fail/Overlap5.hs
index fbf05d4f4e..6338de1844 100644
--- a/testsuite/tests/indexed-types/should_fail/Overlap5.hs
+++ b/testsuite/tests/indexed-types/should_fail/Overlap5.hs
@@ -1,22 +1,9 @@
-{-# LANGUAGE TypeFamilies, DataKinds, PolyKinds #-}
+{-# LANGUAGE TypeFamilies #-}
 
 module Overlap5 where
 
-type family And (a :: Bool) (b :: Bool) :: Bool
-type instance where
-  And False x = False
-  And True x = x
-  And x False = False
-  And x True = x
-  And x x = x
-
-data Proxy p = P
-
-g :: Proxy x -> Proxy (And x True)
-g x = x
-
-h :: Proxy x -> Proxy (And x x)
-h x = x
-
-i :: Proxy x -> Proxy (And False x)
-i x = (P :: Proxy False)
\ No newline at end of file
+type family G a
+type family F a where
+  F Int = Bool
+  G Int = Char
+  F a = Int
\ No newline at end of file
diff --git a/testsuite/tests/indexed-types/should_fail/Overlap5.stderr b/testsuite/tests/indexed-types/should_fail/Overlap5.stderr
index 0413002ab5..201dc416c1 100644
--- a/testsuite/tests/indexed-types/should_fail/Overlap5.stderr
+++ b/testsuite/tests/indexed-types/should_fail/Overlap5.stderr
@@ -1,29 +1,5 @@
 
-Overlap5.hs:16:7:
-    Couldn't match type ‛x’ with ‛And x 'True’
-      ‛x’ is a rigid type variable bound by
-          the type signature for
-            g :: Proxy Bool x -> Proxy Bool (And x 'True)
-          at Overlap5.hs:15:6
-    Expected type: Proxy Bool (And x 'True)
-      Actual type: Proxy Bool x
-    Relevant bindings include
-      g :: Proxy Bool x -> Proxy Bool (And x 'True)
-        (bound at Overlap5.hs:16:1)
-      x :: Proxy Bool x (bound at Overlap5.hs:16:3)
-    In the expression: x
-    In an equation for ‛g’: g x = x
-
-Overlap5.hs:19:7:
-    Couldn't match type ‛x’ with ‛And x x’
-      ‛x’ is a rigid type variable bound by
-          the type signature for h :: Proxy Bool x -> Proxy Bool (And x x)
-          at Overlap5.hs:18:6
-    Expected type: Proxy Bool (And x x)
-      Actual type: Proxy Bool x
-    Relevant bindings include
-      h :: Proxy Bool x -> Proxy Bool (And x x)
-        (bound at Overlap5.hs:19:1)
-      x :: Proxy Bool x (bound at Overlap5.hs:19:3)
-    In the expression: x
-    In an equation for ‛h’: h x = x
+Overlap5.hs:8:3:
+    Mismatched type names in closed type family declaration.
+    First name was F; this one is G
+    In the family declaration for ‛F’
diff --git a/testsuite/tests/indexed-types/should_fail/Overlap6.hs b/testsuite/tests/indexed-types/should_fail/Overlap6.hs
index c97992e65f..a6fc9e7836 100644
--- a/testsuite/tests/indexed-types/should_fail/Overlap6.hs
+++ b/testsuite/tests/indexed-types/should_fail/Overlap6.hs
@@ -2,8 +2,7 @@
 
 module Overlap6 where
 
-type family And (a :: Bool) (b :: Bool) :: Bool
-type instance where
+type family And (a :: Bool) (b :: Bool) :: Bool where
   And False x = False
   And True x = False -- this is wrong!
   And x False = False
diff --git a/testsuite/tests/indexed-types/should_fail/Overlap6.stderr b/testsuite/tests/indexed-types/should_fail/Overlap6.stderr
index c59a1ab72d..ce0a64f8b2 100644
--- a/testsuite/tests/indexed-types/should_fail/Overlap6.stderr
+++ b/testsuite/tests/indexed-types/should_fail/Overlap6.stderr
@@ -1,15 +1,15 @@
 
-Overlap6.hs:16:7:
+Overlap6.hs:15:7:
     Couldn't match type ‛x’ with ‛And x 'True’
       ‛x’ is a rigid type variable bound by
           the type signature for
             g :: Proxy Bool x -> Proxy Bool (And x 'True)
-          at Overlap6.hs:15:6
+          at Overlap6.hs:14:6
     Expected type: Proxy Bool (And x 'True)
       Actual type: Proxy Bool x
     Relevant bindings include
       g :: Proxy Bool x -> Proxy Bool (And x 'True)
-        (bound at Overlap6.hs:16:1)
-      x :: Proxy Bool x (bound at Overlap6.hs:16:3)
+        (bound at Overlap6.hs:15:1)
+      x :: Proxy Bool x (bound at Overlap6.hs:15:3)
     In the expression: x
     In an equation for ‛g’: g x = x
diff --git a/testsuite/tests/indexed-types/should_fail/Overlap7.hs b/testsuite/tests/indexed-types/should_fail/Overlap7.hs
index 352103c4c0..a6988f4e34 100644
--- a/testsuite/tests/indexed-types/should_fail/Overlap7.hs
+++ b/testsuite/tests/indexed-types/should_fail/Overlap7.hs
@@ -2,8 +2,7 @@
 
 module Overlap7 where
 
-type family F a b
-type instance where
+type family F a b where
   F Int a = Int
   F a b = Bool
 type instance F a Int = Int
diff --git a/testsuite/tests/indexed-types/should_fail/Overlap7.stderr b/testsuite/tests/indexed-types/should_fail/Overlap7.stderr
index a87186eec9..2858f792b2 100644
--- a/testsuite/tests/indexed-types/should_fail/Overlap7.stderr
+++ b/testsuite/tests/indexed-types/should_fail/Overlap7.stderr
@@ -1,10 +1,4 @@
 
-Overlap7.hs:7:3:
-    Conflicting family instance declarations:
-      F Int a -- Defined at Overlap7.hs:7:3
-      F a Int -- Defined at Overlap7.hs:9:15
-
-Overlap7.hs:8:3:
-    Conflicting family instance declarations:
-      F a b -- Defined at Overlap7.hs:8:3
-      F a Int -- Defined at Overlap7.hs:9:15
+Overlap7.hs:8:1:
+    Illegal instance for closed family ‛F’
+    In the type instance declaration for ‛F’
diff --git a/testsuite/tests/indexed-types/should_fail/Overlap8.hs b/testsuite/tests/indexed-types/should_fail/Overlap8.hs
deleted file mode 100644
index b998d26614..0000000000
--- a/testsuite/tests/indexed-types/should_fail/Overlap8.hs
+++ /dev/null
@@ -1,11 +0,0 @@
-{-# LANGUAGE TypeFamilies #-}
-
-module Overlap8 where
-
-type family F a b
-type instance F a Int = Int
-type instance where
-  F Int a = Int
-  F a b = Bool
-
-
diff --git a/testsuite/tests/indexed-types/should_fail/Overlap8.stderr b/testsuite/tests/indexed-types/should_fail/Overlap8.stderr
deleted file mode 100644
index 9443a4636f..0000000000
--- a/testsuite/tests/indexed-types/should_fail/Overlap8.stderr
+++ /dev/null
@@ -1,5 +0,0 @@
-
-Overlap8.hs:6:15:
-    Conflicting family instance declarations:
-      F a Int -- Defined at Overlap8.hs:6:15
-      F Int a -- Defined at Overlap8.hs:8:3
diff --git a/testsuite/tests/indexed-types/should_fail/Overlap9.hs b/testsuite/tests/indexed-types/should_fail/Overlap9.hs
index 61d1dff72f..19e1c989f1 100644
--- a/testsuite/tests/indexed-types/should_fail/Overlap9.hs
+++ b/testsuite/tests/indexed-types/should_fail/Overlap9.hs
@@ -2,8 +2,7 @@
 
 module Overlap9 where
 
-type family F a
-type instance where
+type family F a where
   F Int = Bool
   F a   = Int
 
diff --git a/testsuite/tests/indexed-types/should_fail/Overlap9.stderr b/testsuite/tests/indexed-types/should_fail/Overlap9.stderr
index a0a6ea8ee6..9f9f102cc1 100644
--- a/testsuite/tests/indexed-types/should_fail/Overlap9.stderr
+++ b/testsuite/tests/indexed-types/should_fail/Overlap9.stderr
@@ -1,11 +1,11 @@
 
-Overlap9.hs:11:7:
+Overlap9.hs:10:7:
     Could not deduce (F a ~ Int)
     from the context (Show a)
       bound by the type signature for g :: Show a => a -> F a
-      at Overlap9.hs:10:6-23
+      at Overlap9.hs:9:6-23
     Relevant bindings include
-      g :: a -> F a (bound at Overlap9.hs:11:1)
-      x :: a (bound at Overlap9.hs:11:3)
+      g :: a -> F a (bound at Overlap9.hs:10:1)
+      x :: a (bound at Overlap9.hs:10:3)
     In the expression: length (show x)
     In an equation for ‛g’: g x = length (show x)
diff --git a/testsuite/tests/indexed-types/should_fail/SimpleFail1a.stderr b/testsuite/tests/indexed-types/should_fail/SimpleFail1a.stderr
index 7108a5ba73..2e7b982a6b 100644
--- a/testsuite/tests/indexed-types/should_fail/SimpleFail1a.stderr
+++ b/testsuite/tests/indexed-types/should_fail/SimpleFail1a.stderr
@@ -1,4 +1,4 @@
 
 SimpleFail1a.hs:4:1:
-    Number of parameters must match family declaration; expected 2
+    Couldn't match kind ‛* -> *’ against ‛*’
     In the data instance declaration for ‛T1’
diff --git a/testsuite/tests/indexed-types/should_fail/SimpleFail1b.stderr b/testsuite/tests/indexed-types/should_fail/SimpleFail1b.stderr
index a65a50d2c2..8a3f5dfbcd 100644
--- a/testsuite/tests/indexed-types/should_fail/SimpleFail1b.stderr
+++ b/testsuite/tests/indexed-types/should_fail/SimpleFail1b.stderr
@@ -1,4 +1,4 @@
 
 SimpleFail1b.hs:4:1:
-    Number of parameters must match family declaration; expected 2
+    Number of parameters must match family declaration; expected no more than 2
     In the data instance declaration for ‛T1’
diff --git a/testsuite/tests/indexed-types/should_fail/T5515.stderr b/testsuite/tests/indexed-types/should_fail/T5515.stderr
index c3d6b9f664..f8056f0dd9 100644
--- a/testsuite/tests/indexed-types/should_fail/T5515.stderr
+++ b/testsuite/tests/indexed-types/should_fail/T5515.stderr
@@ -1,8 +1,8 @@
 
-T5515.hs:9:8:
+T5515.hs:9:3:
     The RHS of an associated type declaration mentions type variable ‛a’
       All such variables must be bound on the LHS
 
-T5515.hs:15:8:
+T5515.hs:15:3:
     The RHS of an associated type declaration mentions type variable ‛a’
       All such variables must be bound on the LHS
diff --git a/testsuite/tests/indexed-types/should_fail/T7560.hs b/testsuite/tests/indexed-types/should_fail/T7560.hs
deleted file mode 100644
index 0176c5a408..0000000000
--- a/testsuite/tests/indexed-types/should_fail/T7560.hs
+++ /dev/null
@@ -1,13 +0,0 @@
-{-# LANGUAGE TypeFamilies #-}
-
-module T7560 where
-
-type family F a
-
-type instance where
-  F Int = Int
-  F Bool = Bool
-
-type instance where
-  F Int = Char
-  F Double = Double
\ No newline at end of file
diff --git a/testsuite/tests/indexed-types/should_fail/T7560.stderr b/testsuite/tests/indexed-types/should_fail/T7560.stderr
deleted file mode 100644
index e382fb3d78..0000000000
--- a/testsuite/tests/indexed-types/should_fail/T7560.stderr
+++ /dev/null
@@ -1,5 +0,0 @@
-
-T7560.hs:8:3:
-    Conflicting family instance declarations:
-      F Int -- Defined at T7560.hs:8:3
-      F Int -- Defined at T7560.hs:12:3
diff --git a/testsuite/tests/indexed-types/should_fail/T7786.hs b/testsuite/tests/indexed-types/should_fail/T7786.hs
index f2d119ba10..59c5fecab8 100644
--- a/testsuite/tests/indexed-types/should_fail/T7786.hs
+++ b/testsuite/tests/indexed-types/should_fail/T7786.hs
@@ -50,8 +50,7 @@ buryUnder (ps `Snoc` p) post acc = (ps `buryUnder` post) acc `Snoc` (p `under` p
 type key `KeyNotIn` inv = Intersect (More Empty key) inv ~ Empty
 type (lhs `UnderDisjoint` post) rhs = Intersect ((lhs `BuriedUnder` post) Empty) rhs ~ Empty
 
-type family Intersect (l :: Inventory a) (r :: Inventory a) :: Inventory a
-type instance where
+type family Intersect (l :: Inventory a) (r :: Inventory a) :: Inventory a where
   Intersect Empty r = Empty
   Intersect l Empty = Empty
   Intersect (More ls l) r = InterAppend (Intersect ls r) r l
@@ -59,8 +58,7 @@ type instance where
 type family InterAppend (l :: Inventory a) 
                         (r :: Inventory a) 
                         (one :: a) 
-            :: Inventory a
-type instance where
+            :: Inventory a where
   InterAppend acc Empty one = acc
   InterAppend acc (More rs one) one = More acc one
   InterAppend acc (More rs r) one = InterAppend acc rs one
@@ -68,8 +66,7 @@ type instance where
 type family BuriedUnder (sub :: Inventory [KeySegment]) 
                         (post :: [KeySegment]) 
                         (inv :: Inventory [KeySegment]) 
-            :: Inventory [KeySegment]
-type instance where
+            :: Inventory [KeySegment] where
   BuriedUnder Empty post inv = inv
   BuriedUnder (More ps p) post inv = More ((ps `BuriedUnder` post) inv) (p `Under` post)
 
diff --git a/testsuite/tests/indexed-types/should_fail/T7786.stderr b/testsuite/tests/indexed-types/should_fail/T7786.stderr
index 359c84fe71..85a1be23d5 100644
--- a/testsuite/tests/indexed-types/should_fail/T7786.stderr
+++ b/testsuite/tests/indexed-types/should_fail/T7786.stderr
@@ -1,5 +1,5 @@
 
-T7786.hs:89:22:
+T7786.hs:86:22:
     Couldn't match type ‛xxx’ with ‛'Empty [KeySegment]’
     Inaccessible code in
       a pattern with constructor
diff --git a/testsuite/tests/indexed-types/should_fail/all.T b/testsuite/tests/indexed-types/should_fail/all.T
index da6d4a1950..ed0e070879 100644
--- a/testsuite/tests/indexed-types/should_fail/all.T
+++ b/testsuite/tests/indexed-types/should_fail/all.T
@@ -82,7 +82,6 @@ test('Overlap4', normal, compile_fail, [''])
 test('Overlap5', normal, compile_fail, [''])
 test('Overlap6', normal, compile_fail, [''])
 test('Overlap7', normal, compile_fail, [''])
-test('Overlap8', normal, compile_fail, [''])
 test('Overlap9', normal, compile_fail, [''])
 test('Overlap10', normal, compile_fail, [''])
 test('Overlap11', normal, compile_fail, [''])
@@ -94,8 +93,10 @@ test('T7354a',
      ['$MAKE -s --no-print-directory T7354a'])
 test('T7536', normal, compile_fail, [''])
 
-test('T7560', normal, compile_fail, [''])
 test('T7729', normal, compile_fail, [''])
 test('T7729a', normal, compile_fail, [''])
 test('T7786', normal, compile_fail, [''])
+
+test('NoGood', normal, compile_fail, [''])
 test('T7967', normal, compile_fail, [''])
+
diff --git a/testsuite/tests/th/ClosedFam1.hs b/testsuite/tests/th/ClosedFam1.hs
new file mode 100644
index 0000000000..262e9a1e48
--- /dev/null
+++ b/testsuite/tests/th/ClosedFam1.hs
@@ -0,0 +1,13 @@
+{-# LANGUAGE TemplateHaskell, TypeFamilies, PolyKinds, DataKinds #-}
+
+module ClosedFam1 where
+
+import Language.Haskell.TH
+
+$(do { decl <- [d| type family Foo a (b :: k) where
+                     Foo Int Bool = Int
+                     Foo a Maybe = Bool
+                     Foo b (x :: Bool) = Char |]
+     ; reportWarning (pprint decl)
+     ; return [] })
+
diff --git a/testsuite/tests/th/ClosedFam1.stderr b/testsuite/tests/th/ClosedFam1.stderr
new file mode 100644
index 0000000000..d9827d8afb
--- /dev/null
+++ b/testsuite/tests/th/ClosedFam1.stderr
@@ -0,0 +1,6 @@
+
+ClosedFam1.hs:7:3: Warning:
+    type family Foo_0 a_1 (b_2 :: k_3) where
+    Foo_0 GHC.Types.Int GHC.Types.Bool = GHC.Types.Int
+    Foo_0 a_4 Data.Maybe.Maybe = GHC.Types.Bool
+    Foo_0 b_5 (x_6 :: GHC.Types.Bool) = GHC.Types.Char
diff --git a/testsuite/tests/th/ClosedFam2.hs b/testsuite/tests/th/ClosedFam2.hs
new file mode 100644
index 0000000000..cd2dc2de60
--- /dev/null
+++ b/testsuite/tests/th/ClosedFam2.hs
@@ -0,0 +1,22 @@
+{-# LANGUAGE TemplateHaskell, TypeFamilies, PolyKinds #-}
+
+module ClosedFam2 where
+
+import Language.Haskell.TH
+
+$( return [ ClosedTypeFamilyD (mkName "Equals")
+                              [ KindedTV (mkName "a") (VarT (mkName "k"))
+                              , KindedTV (mkName "b") (VarT (mkName "k")) ]
+                              Nothing
+                              [ TySynEqn [ (VarT (mkName "a"))
+                                         , (VarT (mkName "a")) ]
+                                         (ConT (mkName "Int"))
+                              , TySynEqn [ (VarT (mkName "a"))
+                                         , (VarT (mkName "b")) ]
+                                         (ConT (mkName "Bool")) ] ])
+
+a :: Equals b b
+a = (5 :: Int)
+
+b :: Equals Int Bool
+b = False
diff --git a/testsuite/tests/th/T5886a.hs b/testsuite/tests/th/T5886a.hs
index 74db6fa192..4d2cec6207 100644
--- a/testsuite/tests/th/T5886a.hs
+++ b/testsuite/tests/th/T5886a.hs
@@ -11,4 +11,4 @@ class C α where
 
 bang ∷ DecsQ
 bang = return [InstanceD [] (AppT (ConT ''C) (ConT ''Int))
-                [TySynInstD ''AT [TySynEqn [ConT ''Int] (ConT ''Int)]]]
+                [TySynInstD ''AT (TySynEqn [ConT ''Int] (ConT ''Int))]]
diff --git a/testsuite/tests/th/TH_TyInstWhere1.hs b/testsuite/tests/th/TH_TyInstWhere1.hs
index 8352d4bf01..d8c07d7642 100644
--- a/testsuite/tests/th/TH_TyInstWhere1.hs
+++ b/testsuite/tests/th/TH_TyInstWhere1.hs
@@ -2,9 +2,7 @@
 
 module TH_TyInstWhere1 where
 
-type family F (a :: k) (b :: k) :: Bool
-
-$([d| type instance where
+$([d| type family F (a :: k) (b :: k) :: Bool where
         F a a = True
         F a b = False |])
 
diff --git a/testsuite/tests/th/TH_TyInstWhere1.stderr b/testsuite/tests/th/TH_TyInstWhere1.stderr
index 480e5bf4f7..5a830aa792 100644
--- a/testsuite/tests/th/TH_TyInstWhere1.stderr
+++ b/testsuite/tests/th/TH_TyInstWhere1.stderr
@@ -1,9 +1,9 @@
 TH_TyInstWhere1.hs:1:1: Splicing declarations
-    [d| type instance where
+    [d| type family F (a :: k) (b :: k) :: Bool where
           F a a = True
           F a b = False |]
   ======>
-    TH_TyInstWhere1.hs:(7,3)-(9,24)
-    type instance where
+    TH_TyInstWhere1.hs:(5,3)-(7,24)
+    type family F (a :: k) (b :: k) :: Bool where
       F a a = True
       F a b = False
diff --git a/testsuite/tests/th/TH_TyInstWhere2.hs b/testsuite/tests/th/TH_TyInstWhere2.hs
index ec27ced780..47fedad8da 100644
--- a/testsuite/tests/th/TH_TyInstWhere2.hs
+++ b/testsuite/tests/th/TH_TyInstWhere2.hs
@@ -4,9 +4,7 @@ module TH_TyInstWhere2 where
 
 import Language.Haskell.TH
 
-type family F (a :: k) (b :: k) :: Bool
-
-$( do { decs <- [d| type instance where
+$( do { decs <- [d| type family F (a :: k) (b :: k) :: Bool where
                       F a a = True
                       F a b = False |]
       ; reportWarning (pprint decs)
diff --git a/testsuite/tests/th/TH_TyInstWhere2.stderr b/testsuite/tests/th/TH_TyInstWhere2.stderr
index 4ed490e8ea..17caf61bad 100644
--- a/testsuite/tests/th/TH_TyInstWhere2.stderr
+++ b/testsuite/tests/th/TH_TyInstWhere2.stderr
@@ -1,5 +1,5 @@
 
-TH_TyInstWhere2.hs:9:4: Warning:
-    type instance where
-    TH_TyInstWhere2.F a_0 a_0 = 'GHC.Types.True
-    TH_TyInstWhere2.F a_1 b_2 = 'GHC.Types.False
+TH_TyInstWhere2.hs:7:4: Warning:
+    type family F_0 (a_1 :: k_2) (b_3 :: k_2) :: GHC.Types.Bool where
+    F_0 a_4 a_4 = 'GHC.Types.True
+    F_0 a_5 b_6 = 'GHC.Types.False
diff --git a/testsuite/tests/th/TH_TyInstWhere3.hs b/testsuite/tests/th/TH_TyInstWhere3.hs
deleted file mode 100644
index 54d76f5226..0000000000
--- a/testsuite/tests/th/TH_TyInstWhere3.hs
+++ /dev/null
@@ -1,18 +0,0 @@
-{-# LANGUAGE PolyKinds, DataKinds, TemplateHaskell, TypeFamilies #-}
-
-module TH_TyInstWhere3 where
-
-import Language.Haskell.TH
-
-type family F a
-
-$( do { decs <- [d| type instance where
-                      F Int = Int |]
-      ; reportWarning (pprint decs)
-      ; return decs })
-
-type instance F a = a 
-
--- When this test was written, TH considered all singleton type family instance
--- as unbranched. Thus, even though the two instances above would not play nicely
--- without TH, they should be fine with TH.
diff --git a/testsuite/tests/th/TH_TyInstWhere3.stderr b/testsuite/tests/th/TH_TyInstWhere3.stderr
deleted file mode 100644
index eaebfec89f..0000000000
--- a/testsuite/tests/th/TH_TyInstWhere3.stderr
+++ /dev/null
@@ -1,3 +0,0 @@
-
-TH_TyInstWhere3.hs:9:4: Warning:
-    type instance TH_TyInstWhere3.F GHC.Types.Int = GHC.Types.Int
diff --git a/testsuite/tests/th/TH_TyInstWhere4.hs b/testsuite/tests/th/TH_TyInstWhere4.hs
deleted file mode 100644
index 86415ffd5d..0000000000
--- a/testsuite/tests/th/TH_TyInstWhere4.hs
+++ /dev/null
@@ -1,20 +0,0 @@
-{-# LANGUAGE PolyKinds, DataKinds, TemplateHaskell, TypeFamilies #-}
-
-module TH_TyInstWhere4 where
-
-import Language.Haskell.TH
-
-type family F a b :: Bool
-type instance where
-  F a a = True
-  F a b = False
-
-$( do { info1 <- reify ''F
-      ; reportWarning (pprint info1)
-      ; info2 <- reifyInstances ''F [ConT ''Int, ConT ''Int]
-      ; reportWarning (pprint info2)
-      ; info3 <- reifyInstances ''F [ConT ''Int, ConT ''Bool]
-      ; reportWarning (pprint info3)
-      ; return [] })
-
-
diff --git a/testsuite/tests/th/TH_TyInstWhere4.stderr b/testsuite/tests/th/TH_TyInstWhere4.stderr
deleted file mode 100644
index 70dfe85b7a..0000000000
--- a/testsuite/tests/th/TH_TyInstWhere4.stderr
+++ /dev/null
@@ -1,16 +0,0 @@
-
-TH_TyInstWhere4.hs:12:4: Warning:
-    type family TH_TyInstWhere4.F a_0 b_1 :: * -> * -> GHC.Types.Bool
-type instance where
-    TH_TyInstWhere4.F a_2 a_2 = GHC.Types.True
-    TH_TyInstWhere4.F a_3 b_4 = GHC.Types.False
-
-TH_TyInstWhere4.hs:12:4: Warning:
-    type instance where
-    TH_TyInstWhere4.F a_0 a_0 = GHC.Types.True
-    TH_TyInstWhere4.F a_1 b_2 = GHC.Types.False
-
-TH_TyInstWhere4.hs:12:4: Warning:
-    type instance where
-    TH_TyInstWhere4.F a_0 a_0 = GHC.Types.True
-    TH_TyInstWhere4.F a_1 b_2 = GHC.Types.False
diff --git a/testsuite/tests/th/all.T b/testsuite/tests/th/all.T
index ad1c4e9782..c6407c462e 100644
--- a/testsuite/tests/th/all.T
+++ b/testsuite/tests/th/all.T
@@ -261,8 +261,6 @@ test('T7276a', combined_output, ghci_script, ['T7276a.script'])
 
 test('TH_TyInstWhere1', normal, compile, ['-v0 -ddump-splices -dsuppress-uniques'])
 test('TH_TyInstWhere2', normal, compile, ['-v0'])
-test('TH_TyInstWhere3', normal, compile, ['-v0'])
-test('TH_TyInstWhere4', normal, compile, ['-v0'])
 
 test('T7445', extra_clean(['T7445a.hi', 'T7445a.o']),
 	      run_command,
@@ -275,3 +273,6 @@ test('T2222', normal, compile, ['-v0'])
 test('T1849', normal, ghci_script, ['T1849.script'])
 test('T7681', normal, compile, ['-v0'])
 test('T7910', normal, compile_and_run, ['-v0'])
+
+test('ClosedFam1', normal, compile, ['-dsuppress-uniques -v0'])
+test('ClosedFam2', normal, compile, ['-v0'])
\ No newline at end of file
diff --git a/testsuite/tests/typecheck/should_compile/T5481.stderr b/testsuite/tests/typecheck/should_compile/T5481.stderr
index 931c3e0420..bf59427da6 100644
--- a/testsuite/tests/typecheck/should_compile/T5481.stderr
+++ b/testsuite/tests/typecheck/should_compile/T5481.stderr
@@ -1,8 +1,8 @@
 
-T5481.hs:6:10:
+T5481.hs:6:5:
     The RHS of an associated type declaration mentions type variable ‛b’
       All such variables must be bound on the LHS
 
-T5481.hs:8:10:
+T5481.hs:8:5:
     The RHS of an associated type declaration mentions type variable ‛a’
       All such variables must be bound on the LHS
diff --git a/testsuite/tests/typecheck/should_fail/AssocTyDef05.stderr b/testsuite/tests/typecheck/should_fail/AssocTyDef05.stderr
index 401251e36a..5d003e9a42 100644
--- a/testsuite/tests/typecheck/should_fail/AssocTyDef05.stderr
+++ b/testsuite/tests/typecheck/should_fail/AssocTyDef05.stderr
@@ -1,5 +1,5 @@
 
 AssocTyDef05.hs:6:10:
     Number of parameters must match family declaration; expected 1
-    In the type instance declaration for ‛Typ’
+    In the type synonym instance default declaration for ‛Typ’
     In the class declaration for ‛Cls’
diff --git a/testsuite/tests/typecheck/should_fail/AssocTyDef06.stderr b/testsuite/tests/typecheck/should_fail/AssocTyDef06.stderr
index 91e92bdcae..fb7f91033c 100644
--- a/testsuite/tests/typecheck/should_fail/AssocTyDef06.stderr
+++ b/testsuite/tests/typecheck/should_fail/AssocTyDef06.stderr
@@ -1,5 +1,5 @@
 
 AssocTyDef06.hs:6:10:
-    Number of parameters must match family declaration; expected 1
+    Number of parameters must match family declaration; expected no more than 1
     In the type instance declaration for ‛Typ’
     In the class declaration for ‛Cls’