Update outputs following the unicode quote change in GHC's output

26 files changed, 114 insertions, 114 deletions

diff --git a/testsuite/tests/ghci/prog006/prog006.stderr b/testsuite/tests/ghci/prog006/prog006.stderr
index 472272a01e..53c82d5466 100644
--- a/testsuite/tests/ghci/prog006/prog006.stderr
+++ b/testsuite/tests/ghci/prog006/prog006.stderr
@@ -1,4 +1,4 @@
 
 Boot.hs:5:13:
-    Not a data constructor: `forall'
+    Not a data constructor: ‛forall’
     Perhaps you intended to use -XExistentialQuantification
diff --git a/testsuite/tests/ghci/prog009/ghci.prog009.stderr b/testsuite/tests/ghci/prog009/ghci.prog009.stderr
index e63a322c2d..bf608499bb 100644
--- a/testsuite/tests/ghci/prog009/ghci.prog009.stderr
+++ b/testsuite/tests/ghci/prog009/ghci.prog009.stderr
@@ -2,7 +2,7 @@
 A.hs:1:16: parse error on input `where'
 
 <interactive>:26:1:
-    Not in scope: `yan'
-    Perhaps you meant `tan' (imported from Prelude)
+    Not in scope: ‛yan’
+    Perhaps you meant ‛tan’ (imported from Prelude)
 
 A.hs:1:16: parse error on input `where'
diff --git a/testsuite/tests/ghci/prog012/prog012.stderr b/testsuite/tests/ghci/prog012/prog012.stderr
index 71f2bbeb01..db122d9c64 100644
--- a/testsuite/tests/ghci/prog012/prog012.stderr
+++ b/testsuite/tests/ghci/prog012/prog012.stderr
@@ -1,2 +1,2 @@
 
-Bar.hs:3:7: Not in scope: `nonexistent'
+Bar.hs:3:7: Not in scope: ‛nonexistent’
diff --git a/testsuite/tests/ghci/scripts/T2452.stderr b/testsuite/tests/ghci/scripts/T2452.stderr
index 2802ee2bdf..a2fa4fc8a5 100644
--- a/testsuite/tests/ghci/scripts/T2452.stderr
+++ b/testsuite/tests/ghci/scripts/T2452.stderr
@@ -1,2 +1,2 @@
 
-<interactive>:1:1: Not in scope: `System.IO.hPutStrLn'
+<interactive>:1:1: Not in scope: ‛System.IO.hPutStrLn’
diff --git a/testsuite/tests/ghci/scripts/T2816.stderr b/testsuite/tests/ghci/scripts/T2816.stderr
index 3a9e972205..ba4c1bd955 100644
--- a/testsuite/tests/ghci/scripts/T2816.stderr
+++ b/testsuite/tests/ghci/scripts/T2816.stderr
@@ -1,2 +1,2 @@
 
-<interactive>:2:1: Not in scope: `α'
+<interactive>:2:1: Not in scope: ‛α’
diff --git a/testsuite/tests/ghci/scripts/T4127a.stderr b/testsuite/tests/ghci/scripts/T4127a.stderr
index 970b6db0a2..cc118a9e20 100644
--- a/testsuite/tests/ghci/scripts/T4127a.stderr
+++ b/testsuite/tests/ghci/scripts/T4127a.stderr
@@ -1,5 +1,5 @@
 
 <interactive>:3:68:
-    Multiple declarations of `f'
+    Multiple declarations of ‛f’
     Declared at: <interactive>:3:32
                  <interactive>:3:68
diff --git a/testsuite/tests/ghci/scripts/T5545.stdout b/testsuite/tests/ghci/scripts/T5545.stdout
index 8c7c69ad58..8ba680a5cb 100644
--- a/testsuite/tests/ghci/scripts/T5545.stdout
+++ b/testsuite/tests/ghci/scripts/T5545.stdout
@@ -1,2 +1,2 @@
-($!) :: (a -> b) -> a -> b 	-- Defined in `Prelude'
+($!) :: (a -> b) -> a -> b 	-- Defined in ‛Prelude’
 infixr 0 $!
diff --git a/testsuite/tests/ghci/scripts/T5564.stderr b/testsuite/tests/ghci/scripts/T5564.stderr
index d76c4df788..6fb94e4f13 100644
--- a/testsuite/tests/ghci/scripts/T5564.stderr
+++ b/testsuite/tests/ghci/scripts/T5564.stderr
@@ -1,9 +1,9 @@
 
 <interactive>:3:1:
-    Not in scope: `git'
-    Perhaps you meant `it' (line 2)
+    Not in scope: ‛git’
+    Perhaps you meant ‛it’ (line 2)
 
 <interactive>:5:1:
-    Not in scope: `fit'
+    Not in scope: ‛fit’
     Perhaps you meant one of these:
-      `it' (line 4), `fst' (imported from Prelude)
+      ‛it’ (line 4), ‛fst’ (imported from Prelude)
diff --git a/testsuite/tests/ghci/scripts/T5836.stderr b/testsuite/tests/ghci/scripts/T5836.stderr
index 9b0cfc65eb..5bd37b5c00 100644
--- a/testsuite/tests/ghci/scripts/T5836.stderr
+++ b/testsuite/tests/ghci/scripts/T5836.stderr
@@ -1,4 +1,4 @@
 
 <no location info>:
-    Could not find module `Does.Not.Exist'
+    Could not find module ‛Does.Not.Exist’
     It is not a module in the current program, or in any known package.
diff --git a/testsuite/tests/ghci/scripts/T5979.stderr b/testsuite/tests/ghci/scripts/T5979.stderr
index 84f8c6ba0b..b4cd884928 100644
--- a/testsuite/tests/ghci/scripts/T5979.stderr
+++ b/testsuite/tests/ghci/scripts/T5979.stderr
@@ -1,4 +1,4 @@
 
 <no location info>:
-    Could not find module `Control.Monad.Trans.State'
+    Could not find module ‛Control.Monad.Trans.State’
     It is not a module in the current program, or in any known package.
diff --git a/testsuite/tests/ghci/scripts/T6007.stderr b/testsuite/tests/ghci/scripts/T6007.stderr
index b461ef19bf..695d25b3ad 100644
--- a/testsuite/tests/ghci/scripts/T6007.stderr
+++ b/testsuite/tests/ghci/scripts/T6007.stderr
@@ -1,6 +1,6 @@
 
 <interactive>:1:19:
-    Module `System.IO' does not export `does_not_exist'
+    Module ‛System.IO’ does not export ‛does_not_exist’
 
 <interactive>:1:20:
-    Module `Data.Maybe' does not export `does_not_exist'
+    Module ‛Data.Maybe’ does not export ‛does_not_exist’
diff --git a/testsuite/tests/ghci/scripts/ghci008.stdout b/testsuite/tests/ghci/scripts/ghci008.stdout
index cac9db2c41..9eaf1dc961 100644
--- a/testsuite/tests/ghci/scripts/ghci008.stdout
+++ b/testsuite/tests/ghci/scripts/ghci008.stdout
@@ -1,18 +1,18 @@
 class Num a where
   (+) :: a -> a -> a
   ...
-  	-- Defined in `GHC.Num'
+  	-- Defined in ‛GHC.Num’
 infixl 6 +
 class Num a where
   (+) :: a -> a -> a
   ...
-  	-- Defined in `GHC.Num'
+  	-- Defined in ‛GHC.Num’
 infixl 6 +
 data Data.Complex.Complex a = !a Data.Complex.:+ !a
-  	-- Defined in `Data.Complex'
+  	-- Defined in ‛Data.Complex’
 infix 6 Data.Complex.:+
 data Data.Complex.Complex a = !a Data.Complex.:+ !a
-  	-- Defined in `Data.Complex'
+  	-- Defined in ‛Data.Complex’
 infix 6 Data.Complex.:+
 class (RealFrac a, Floating a) => RealFloat a where
   floatRadix :: a -> Integer
@@ -29,8 +29,8 @@ class (RealFrac a, Floating a) => RealFloat a where
   isNegativeZero :: a -> Bool
   isIEEE :: a -> Bool
   atan2 :: a -> a -> a
-  	-- Defined in `GHC.Float'
-instance RealFloat Float -- Defined in `GHC.Float'
-instance RealFloat Double -- Defined in `GHC.Float'
+  	-- Defined in ‛GHC.Float’
+instance RealFloat Float -- Defined in ‛GHC.Float’
+instance RealFloat Double -- Defined in ‛GHC.Float’
 Data.List.isPrefixOf :: Eq a => [a] -> [a] -> Bool
-  	-- Defined in `Data.List'
+  	-- Defined in ‛Data.List’
diff --git a/testsuite/tests/ghci/scripts/ghci011.stdout b/testsuite/tests/ghci/scripts/ghci011.stdout
index caed5d0f0c..540572ea81 100644
--- a/testsuite/tests/ghci/scripts/ghci011.stdout
+++ b/testsuite/tests/ghci/scripts/ghci011.stdout
@@ -1,22 +1,22 @@
-data [] a = [] | a : [a] 	-- Defined in `GHC.Types'
-instance Eq a => Eq [a] -- Defined in `GHC.Classes'
-instance Monad [] -- Defined in `GHC.Base'
-instance Functor [] -- Defined in `GHC.Base'
-instance Ord a => Ord [a] -- Defined in `GHC.Classes'
-instance Read a => Read [a] -- Defined in `GHC.Read'
-instance Show a => Show [a] -- Defined in `GHC.Show'
-data () = () 	-- Defined in `GHC.Tuple'
-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'
-data (,) a b = (,) a b 	-- Defined in `GHC.Tuple'
+data [] a = [] | a : [a] 	-- Defined in ‛GHC.Types’
+instance Eq a => Eq [a] -- Defined in ‛GHC.Classes’
+instance Monad [] -- Defined in ‛GHC.Base’
+instance Functor [] -- Defined in ‛GHC.Base’
+instance Ord a => Ord [a] -- Defined in ‛GHC.Classes’
+instance Read a => Read [a] -- Defined in ‛GHC.Read’
+instance Show a => Show [a] -- Defined in ‛GHC.Show’
+data () = () 	-- Defined in ‛GHC.Tuple’
+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’
+data (,) a b = (,) a b 	-- Defined in ‛GHC.Tuple’
 instance (Bounded a, Bounded b) => Bounded (a, b)
-  -- Defined in `GHC.Enum'
-instance (Eq a, Eq b) => Eq (a, b) -- Defined in `GHC.Classes'
-instance Functor ((,) a) -- Defined in `GHC.Base'
-instance (Ord a, Ord b) => Ord (a, b) -- Defined in `GHC.Classes'
-instance (Read a, Read b) => Read (a, b) -- Defined in `GHC.Read'
-instance (Show a, Show b) => Show (a, b) -- Defined in `GHC.Show'
+  -- Defined in ‛GHC.Enum’
+instance (Eq a, Eq b) => Eq (a, b) -- Defined in ‛GHC.Classes’
+instance Functor ((,) a) -- Defined in ‛GHC.Base’
+instance (Ord a, Ord b) => Ord (a, b) -- Defined in ‛GHC.Classes’
+instance (Read a, Read b) => Read (a, b) -- Defined in ‛GHC.Read’
+instance (Show a, Show b) => Show (a, b) -- Defined in ‛GHC.Show’
diff --git a/testsuite/tests/ghci/scripts/ghci020.stdout b/testsuite/tests/ghci/scripts/ghci020.stdout
index 333e78570a..6d621d3c1d 100644
--- a/testsuite/tests/ghci/scripts/ghci020.stdout
+++ b/testsuite/tests/ghci/scripts/ghci020.stdout
@@ -1,3 +1,3 @@
-data (->) a b 	-- Defined in `GHC.Prim'
-instance Monad ((->) r) -- Defined in `GHC.Base'
-instance Functor ((->) r) -- Defined in `GHC.Base'
+data (->) a b 	-- Defined in ‛GHC.Prim’
+instance Monad ((->) r) -- Defined in ‛GHC.Base’
+instance Functor ((->) r) -- Defined in ‛GHC.Base’
diff --git a/testsuite/tests/ghci/scripts/ghci021.stderr b/testsuite/tests/ghci/scripts/ghci021.stderr
index ae7c75b6bb..18216b8f18 100644
--- a/testsuite/tests/ghci/scripts/ghci021.stderr
+++ b/testsuite/tests/ghci/scripts/ghci021.stderr
@@ -1,2 +1,2 @@
 
-<no location info>: no such module: `ThisDoesNotExist'
+<no location info>: no such module: ‛ThisDoesNotExist’
diff --git a/testsuite/tests/ghci/scripts/ghci034.stderr b/testsuite/tests/ghci/scripts/ghci034.stderr
index 59501b2443..00bf3dfb67 100644
--- a/testsuite/tests/ghci/scripts/ghci034.stderr
+++ b/testsuite/tests/ghci/scripts/ghci034.stderr
@@ -1,2 +1,2 @@
 
-Top level: Not in scope: `thisIsNotDefined'
+Top level: Not in scope: ‛thisIsNotDefined’
diff --git a/testsuite/tests/ghci/scripts/ghci036.stderr b/testsuite/tests/ghci/scripts/ghci036.stderr
index f070bdd9d2..5b53b08d29 100644
--- a/testsuite/tests/ghci/scripts/ghci036.stderr
+++ b/testsuite/tests/ghci/scripts/ghci036.stderr
@@ -1,18 +1,18 @@
 
-<interactive>:1:1: Not in scope: `nubBy'
+<interactive>:1:1: Not in scope: ‛nubBy’
 
-<interactive>:1:1: Not in scope: `nub'
+<interactive>:1:1: Not in scope: ‛nub’
 
-<interactive>:1:1: Not in scope: `nubBy'
+<interactive>:1:1: Not in scope: ‛nubBy’
 
-<interactive>:1:1: Not in scope: `nub'
+<interactive>:1:1: Not in scope: ‛nub’
 
 <interactive>:1:1:
-    Not in scope: `nub'
-    Perhaps you meant `L.nub' (imported from Data.List)
+    Not in scope: ‛nub’
+    Perhaps you meant ‛L.nub’ (imported from Data.List)
 
 <interactive>:1:1:
-    Failed to load interface for `L'
+    Failed to load interface for ‛L’
     Use -v to see a list of the files searched for.
 
-<interactive>:1:1: Not in scope: `nub'
+<interactive>:1:1: Not in scope: ‛nub’
diff --git a/testsuite/tests/ghci/scripts/ghci038.stderr b/testsuite/tests/ghci/scripts/ghci038.stderr
index 5b3b85c25b..bb2fb850c8 100644
--- a/testsuite/tests/ghci/scripts/ghci038.stderr
+++ b/testsuite/tests/ghci/scripts/ghci038.stderr
@@ -1,4 +1,4 @@
 
-<interactive>:1:1: Not in scope: `map'
+<interactive>:1:1: Not in scope: ‛map’
 
-<interactive>:1:1: Not in scope: `x'
+<interactive>:1:1: Not in scope: ‛x’
diff --git a/testsuite/tests/ghci/scripts/ghci044.stderr b/testsuite/tests/ghci/scripts/ghci044.stderr
index a5e6a543ee..c0737d13b5 100644
--- a/testsuite/tests/ghci/scripts/ghci044.stderr
+++ b/testsuite/tests/ghci/scripts/ghci044.stderr
@@ -1,11 +1,11 @@
 
 <interactive>:5:10:
-    Illegal instance declaration for `C [Int]'
+    Illegal instance declaration for ‛C [Int]’
       (All instance types must be of the form (T a1 ... an)
        where a1 ... an are *distinct type variables*,
        and each type variable appears at most once in the instance head.
        Use -XFlexibleInstances if you want to disable this.)
-    In the instance declaration for `C [Int]'
+    In the instance declaration for ‛C [Int]’
 
 <interactive>:7:10:
     Overlapping instance declarations:
diff --git a/testsuite/tests/ghci/scripts/ghci047.stderr b/testsuite/tests/ghci/scripts/ghci047.stderr
index 0051710378..c888b0492c 100644
--- a/testsuite/tests/ghci/scripts/ghci047.stderr
+++ b/testsuite/tests/ghci/scripts/ghci047.stderr
@@ -1,16 +1,16 @@
 
 <interactive>:38:1:
-    Couldn't match type `HFalse' with `HTrue'
+    Couldn't match type ‛HFalse’ with ‛HTrue’
     Expected type: HTrue
       Actual type: Or HFalse HFalse
     In the expression: f
     In the expression: f $ Baz 'a'
-    In an equation for `it': it = f $ Baz 'a'
+    In an equation for ‛it’: it = f $ Baz 'a'
 
 <interactive>:39:1:
-    Couldn't match type `HFalse' with `HTrue'
+    Couldn't match type ‛HFalse’ with ‛HTrue’
     Expected type: HTrue
       Actual type: Or HFalse HFalse
     In the expression: f
     In the expression: f $ Quz
-    In an equation for `it': it = f $ Quz
+    In an equation for ‛it’: it = f $ Quz
diff --git a/testsuite/tests/ghci/scripts/ghci048.stderr b/testsuite/tests/ghci/scripts/ghci048.stderr
index 408c1e9ee1..3809db88e2 100644
--- a/testsuite/tests/ghci/scripts/ghci048.stderr
+++ b/testsuite/tests/ghci/scripts/ghci048.stderr
@@ -1,10 +1,10 @@
 
 <interactive>:4:16:
-    Multiple declarations of `A'
+    Multiple declarations of ‛A’
     Declared at: <interactive>:4:12
                  <interactive>:4:16
 
 <interactive>:6:16:
-    Multiple declarations of `A'
+    Multiple declarations of ‛A’
     Declared at: <interactive>:6:12
                  <interactive>:6:16
diff --git a/testsuite/tests/ghci/scripts/ghci050.stderr b/testsuite/tests/ghci/scripts/ghci050.stderr
index b2e11a26ef..77c552575a 100644
--- a/testsuite/tests/ghci/scripts/ghci050.stderr
+++ b/testsuite/tests/ghci/scripts/ghci050.stderr
@@ -1,8 +1,8 @@
 
 <interactive>:6:49:
-    Couldn't match expected type `ListableElem (a, a)'
-                with actual type `a'
-      `a' is a rigid type variable bound by
+    Couldn't match expected type ‛ListableElem (a, a)’
+                with actual type ‛a’
+      ‛a’ is a rigid type variable bound by
           the instance declaration at <interactive>:6:10
     Relevant bindings include
       asList :: (a, a) -> [ListableElem (a, a)]
@@ -11,4 +11,4 @@
       b :: a (bound at <interactive>:6:43)
     In the expression: a
     In the expression: [a, b]
-    In an equation for `asList': asList (a, b) = [a, b]
+    In an equation for ‛asList’: asList (a, b) = [a, b]
diff --git a/testsuite/tests/ghci/scripts/ghci051.stderr b/testsuite/tests/ghci/scripts/ghci051.stderr
index 130d0012a2..aec3647664 100644
--- a/testsuite/tests/ghci/scripts/ghci051.stderr
+++ b/testsuite/tests/ghci/scripts/ghci051.stderr
@@ -1,7 +1,7 @@
 
 <interactive>:7:9:
-    Couldn't match type `T' with `main::Interactive.T'
+    Couldn't match type ‛T’ with ‛main::Interactive.T’
     Expected type: T'
       Actual type: T
     In the expression: C :: T'
-    In an equation for `c': c = C :: T'
+    In an equation for ‛c’: c = C :: T'
diff --git a/testsuite/tests/ghci/scripts/ghci052.stderr b/testsuite/tests/ghci/scripts/ghci052.stderr
index c685a2aaaf..2efada5344 100644
--- a/testsuite/tests/ghci/scripts/ghci052.stderr
+++ b/testsuite/tests/ghci/scripts/ghci052.stderr
@@ -1,27 +1,27 @@
 
 <interactive>:7:4:
-    Couldn't match expected type `main::Interactive.Planet'
-                with actual type `Planet'
-    In the first argument of `pn', namely `Mercury'
+    Couldn't match expected type ‛main::Interactive.Planet’
+                with actual type ‛Planet’
+    In the first argument of ‛pn’, namely ‛Mercury’
     In the expression: pn Mercury
-    In an equation for `it': it = pn Mercury
+    In an equation for ‛it’: it = pn Mercury
 
 <interactive>:8:4:
-    Couldn't match expected type `main::Interactive.Planet'
-                with actual type `Planet'
-    In the first argument of `pn', namely `Venus'
+    Couldn't match expected type ‛main::Interactive.Planet’
+                with actual type ‛Planet’
+    In the first argument of ‛pn’, namely ‛Venus’
     In the expression: pn Venus
-    In an equation for `it': it = pn Venus
+    In an equation for ‛it’: it = pn Venus
 
 <interactive>:9:4:
-    Couldn't match expected type `main::Interactive.Planet'
-                with actual type `Planet'
-    In the first argument of `pn', namely `Mars'
+    Couldn't match expected type ‛main::Interactive.Planet’
+                with actual type ‛Planet’
+    In the first argument of ‛pn’, namely ‛Mars’
     In the expression: pn Mars
-    In an equation for `it': it = pn Mars
+    In an equation for ‛it’: it = pn Mars
 
 <interactive>:11:44:
-    Couldn't match expected type `Planet'
-                with actual type `main::Interactive.Planet'
+    Couldn't match expected type ‛Planet’
+                with actual type ‛main::Interactive.Planet’
     In the pattern: Earth
-    In an equation for `pn': pn Earth = "E"
+    In an equation for ‛pn’: pn Earth = "E"
diff --git a/testsuite/tests/ghci/scripts/ghci053.stderr b/testsuite/tests/ghci/scripts/ghci053.stderr
index e08ad91e21..f97df8f63c 100644
--- a/testsuite/tests/ghci/scripts/ghci053.stderr
+++ b/testsuite/tests/ghci/scripts/ghci053.stderr
@@ -1,14 +1,14 @@
 
 <interactive>:8:12:
-    Couldn't match expected type `main::Interactive.Planet'
-                with actual type `Planet'
-    In the second argument of `(==)', namely `Mercury'
+    Couldn't match expected type ‛main::Interactive.Planet’
+                with actual type ‛Planet’
+    In the second argument of ‛(==)’, namely ‛Mercury’
     In the expression: mercury == Mercury
-    In an equation for `it': it = mercury == Mercury
+    In an equation for ‛it’: it = mercury == Mercury
 
 <interactive>:10:10:
-    Couldn't match expected type `Planet'
-                with actual type `main::Interactive.Planet'
-    In the second argument of `(==)', namely `Earth'
+    Couldn't match expected type ‛Planet’
+                with actual type ‛main::Interactive.Planet’
+    In the second argument of ‛(==)’, namely ‛Earth’
     In the expression: Venus == Earth
-    In an equation for `it': it = Venus == Earth
+    In an equation for ‛it’: it = Venus == Earth
diff --git a/testsuite/tests/ghci/scripts/ghci057.stderr b/testsuite/tests/ghci/scripts/ghci057.stderr
index 623bfb3c37..22d0514578 100644
--- a/testsuite/tests/ghci/scripts/ghci057.stderr
+++ b/testsuite/tests/ghci/scripts/ghci057.stderr
@@ -1,17 +1,17 @@
-

-<interactive>:5:1:

-    Illegal generalised algebraic data declaration for `T'

-      (Use -XGADTs to allow GADTs)

-    In the data declaration for `T'

-

-ghci057.hs:3:3:

-    Data constructor `C' has existential type variables, a context, or a specialised result type

-      (Use -XExistentialQuantification or -XGADTs to allow this)

-    In the definition of data constructor `C'

-    In the data declaration for `T'

-

-ghci057.hs:3:3:

-    Data constructor `C' has existential type variables, a context, or a specialised result type

-      (Use -XExistentialQuantification or -XGADTs to allow this)

-    In the definition of data constructor `C'

-    In the data declaration for `T'

+
+<interactive>:5:1:
+    Illegal generalised algebraic data declaration for ‛T’
+      (Use -XGADTs to allow GADTs)
+    In the data declaration for ‛T’
+
+ghci057.hs:3:3:
+    Data constructor ‛C’ has existential type variables, a context, or a specialised result type
+      (Use -XExistentialQuantification or -XGADTs to allow this)
+    In the definition of data constructor ‛C’
+    In the data declaration for ‛T’
+
+ghci057.hs:3:3:
+    Data constructor ‛C’ has existential type variables, a context, or a specialised result type
+      (Use -XExistentialQuantification or -XGADTs to allow this)
+    In the definition of data constructor ‛C’
+    In the data declaration for ‛T’