A ton of error message wibbles

Notably
 * Showing relevant bindings
 * Not suggesting add instance (Num T); see Trac #7222

testsuite/tests/annotations/should_fail/annfail05.stderr

@@ -2,7 +2,5 @@
 annfail05.hs:11:1:
     No instance for (Data.Data.Data NoInstances)
       arising from an annotation
-    Possible fix:
-      add an instance declaration for (Data.Data.Data NoInstances)
     In the expression: NoInstances
     In the annotation: {-# ANN f NoInstances #-}

testsuite/tests/annotations/should_fail/annfail08.stderr

@@ -2,13 +2,10 @@
 annfail08.hs:9:1:
     No instance for (Data.Data.Data (a0 -> a0))
       arising from an annotation
-    Possible fix:
-      add an instance declaration for (Data.Data.Data (a0 -> a0))
     In the expression: (id + 1)
     In the annotation: {-# ANN f (id + 1) #-}
 
 annfail08.hs:9:15:
     No instance for (Num (a0 -> a0)) arising from a use of `+'
-    Possible fix: add an instance declaration for (Num (a0 -> a0))
     In the expression: (id + 1)
     In the annotation: {-# ANN f (id + 1) #-}

testsuite/tests/arrows/should_fail/T5380.stderr

-
-T5380.hs:7:27:
-    Couldn't match expected type `not_bool' with actual type `Bool'
-      `not_bool' is a rigid type variable bound by
-                 the type signature for
-                   testB :: not_bool -> (() -> ()) -> () -> not_unit
-                 at T5380.hs:6:10
-    In the expression: b
-    In the expression: proc () -> if b then f -< () else f -< ()
-    In an equation for `testB':
-        testB b f = proc () -> if b then f -< () else f -< ()
-
-T5380.hs:7:34:
-    Couldn't match type `not_unit' with `()'
-      `not_unit' is a rigid type variable bound by
-                 the type signature for
-                   testB :: not_bool -> (() -> ()) -> () -> not_unit
-                 at T5380.hs:6:10
-    Expected type: () -> not_unit
-      Actual type: () -> ()
-    In the expression: f
-    In the expression: proc () -> if b then f -< () else f -< ()
-    In an equation for `testB':
-        testB b f = proc () -> if b then f -< () else f -< ()
+
+T5380.hs:7:27:
+    Couldn't match expected type `not_bool' with actual type `Bool'
+      `not_bool' is a rigid type variable bound by
+                 the type signature for
+                   testB :: not_bool -> (() -> ()) -> () -> not_unit
+                 at T5380.hs:6:10
+    Relevant bindings include
+      testB :: not_bool -> (() -> ()) -> () -> not_unit
+        (bound at T5380.hs:7:1)
+      b :: not_bool (bound at T5380.hs:7:7)
+    In the expression: b
+    In the expression: proc () -> if b then f -< () else f -< ()
+    In an equation for `testB':
+        testB b f = proc () -> if b then f -< () else f -< ()
+
+T5380.hs:7:34:
+    Couldn't match type `not_unit' with `()'
+      `not_unit' is a rigid type variable bound by
+                 the type signature for
+                   testB :: not_bool -> (() -> ()) -> () -> not_unit
+                 at T5380.hs:6:10
+    Expected type: () -> not_unit
+      Actual type: () -> ()
+    Relevant bindings include
+      testB :: not_bool -> (() -> ()) -> () -> not_unit
+        (bound at T5380.hs:7:1)
+    In the expression: f
+    In the expression: proc () -> if b then f -< () else f -< ()
+    In an equation for `testB':
+        testB b f = proc () -> if b then f -< () else f -< ()

testsuite/tests/deriving/should_fail/T2851.stderr

@@ -3,7 +3,6 @@ T2851.hs:9:15:
     No instance for (Show (F a))
       arising from the 'deriving' clause of a data type declaration
     Possible fix:
-      add an instance declaration for (Show (F a))
-      or use a standalone 'deriving instance' declaration,
-           so you can specify the instance context yourself
+      use a standalone 'deriving instance' declaration,
+        so you can specify the instance context yourself
     When deriving the instance for (Show (D a))

testsuite/tests/deriving/should_fail/T3621.stderr

@@ -3,7 +3,6 @@ T3621.hs:21:21:
     No instance for (MonadState state (State s))
       arising from the 'deriving' clause of a data type declaration
     Possible fix:
-      add an instance declaration for (MonadState state (State s))
-      or use a standalone 'deriving instance' declaration,
-           so you can specify the instance context yourself
+      use a standalone 'deriving instance' declaration,
+        so you can specify the instance context yourself
     When deriving the instance for (MonadState state (WrappedState s))

testsuite/tests/deriving/should_fail/T5287.stderr

@@ -2,6 +2,8 @@
 T5287.hs:6:29:
     No instance for (A e oops)
       arising from the 'deriving' clause of a data type declaration
+    The type variable `oops' is ambiguous
+    Possible fix: add a type signature that fixes these type variable(s)
     Possible fix:
       use a standalone 'deriving instance' declaration,
         so you can specify the instance context yourself

testsuite/tests/deriving/should_fail/drvfail-foldable-traversable1.stderr

-
-drvfail-foldable-traversable1.hs:9:23:
-    No instance for (Functor Trivial1)
-      arising from the 'deriving' clause of a data type declaration
-    Possible fix:
-      add an instance declaration for (Functor Trivial1)
-      or use a standalone 'deriving instance' declaration,
-           so you can specify the instance context yourself
-    When deriving the instance for (Traversable Trivial1)
-
-drvfail-foldable-traversable1.hs:13:22:
-    No instance for (Foldable Trivial2)
-      arising from the 'deriving' clause of a data type declaration
-    Possible fix:
-      add an instance declaration for (Foldable Trivial2)
-      or use a standalone 'deriving instance' declaration,
-           so you can specify the instance context yourself
-    When deriving the instance for (Traversable Trivial2)
-
-drvfail-foldable-traversable1.hs:17:22:
-    Can't make a derived instance of `Foldable Infinite':
-      Constructor `Infinite' must not contain function types
-    In the data declaration for `Infinite'
-
-drvfail-foldable-traversable1.hs:21:22:
-    Can't make a derived instance of `Traversable (Cont r)':
-      Constructor `Cont' must not contain function types
-    In the data declaration for `Cont'
+
+drvfail-foldable-traversable1.hs:9:23:
+    No instance for (Functor Trivial1)
+      arising from the 'deriving' clause of a data type declaration
+    Possible fix:
+      use a standalone 'deriving instance' declaration,
+        so you can specify the instance context yourself
+    When deriving the instance for (Traversable Trivial1)
+
+drvfail-foldable-traversable1.hs:13:22:
+    No instance for (Foldable Trivial2)
+      arising from the 'deriving' clause of a data type declaration
+    Possible fix:
+      use a standalone 'deriving instance' declaration,
+        so you can specify the instance context yourself
+    When deriving the instance for (Traversable Trivial2)
+
+drvfail-foldable-traversable1.hs:17:22:
+    Can't make a derived instance of `Foldable Infinite':
+      Constructor `Infinite' must not contain function types
+    In the data declaration for `Infinite'
+
+drvfail-foldable-traversable1.hs:21:22:
+    Can't make a derived instance of `Traversable (Cont r)':
+      Constructor `Cont' must not contain function types
+    In the data declaration for `Cont'

testsuite/tests/deriving/should_fail/drvfail-functor2.stderr

-
-drvfail-functor2.hs:1:29: Warning:
-    -XDatatypeContexts is deprecated: It was widely considered a misfeature, and has been removed from the Haskell language.
-
-drvfail-functor2.hs:7:14:
-    Can't make a derived instance of `Functor InFunctionArgument':
-      Constructor `InFunctionArgument' must not use the type variable in a function argument
-    In the newtype declaration for `InFunctionArgument'
-
-drvfail-functor2.hs:10:14:
-    Can't make a derived instance of `Functor OnSecondArg':
-      Constructor `OnSecondArg' must use the type variable only as the last argument of a data type
-    In the newtype declaration for `OnSecondArg'
-
-drvfail-functor2.hs:15:14:
-    Cannot derive well-kinded instance of form `Functor (NoArguments ...)'
-      Class `Functor' expects an argument of kind `* -> *'
-    In the newtype declaration for `NoArguments'
-
-drvfail-functor2.hs:20:14:
-    Can't make a derived instance of `Functor StupidConstraint':
-      Data type `StupidConstraint' must not have a class context (Eq a)
-    In the data declaration for `StupidConstraint'
-
-drvfail-functor2.hs:26:14:
-    No instance for (Functor NoFunctor)
-      arising from the 'deriving' clause of a data type declaration
-    Possible fix:
-      add an instance declaration for (Functor NoFunctor)
-      or use a standalone 'deriving instance' declaration,
-           so you can specify the instance context yourself
-    When deriving the instance for (Functor UseNoFunctor)
+
+drvfail-functor2.hs:1:29: Warning:
+    -XDatatypeContexts is deprecated: It was widely considered a misfeature, and has been removed from the Haskell language.
+
+drvfail-functor2.hs:7:14:
+    Can't make a derived instance of `Functor InFunctionArgument':
+      Constructor `InFunctionArgument' must not use the type variable in a function argument
+    In the newtype declaration for `InFunctionArgument'
+
+drvfail-functor2.hs:10:14:
+    Can't make a derived instance of `Functor OnSecondArg':
+      Constructor `OnSecondArg' must use the type variable only as the last argument of a data type
+    In the newtype declaration for `OnSecondArg'
+
+drvfail-functor2.hs:15:14:
+    Cannot derive well-kinded instance of form `Functor (NoArguments ...)'
+      Class `Functor' expects an argument of kind `* -> *'
+    In the newtype declaration for `NoArguments'
+
+drvfail-functor2.hs:20:14:
+    Can't make a derived instance of `Functor StupidConstraint':
+      Data type `StupidConstraint' must not have a class context (Eq a)
+    In the data declaration for `StupidConstraint'
+
+drvfail-functor2.hs:26:14:
+    No instance for (Functor NoFunctor)
+      arising from the 'deriving' clause of a data type declaration
+    Possible fix:
+      use a standalone 'deriving instance' declaration,
+        so you can specify the instance context yourself
+    When deriving the instance for (Functor UseNoFunctor)

testsuite/tests/deriving/should_fail/drvfail001.stderr

@@ -3,7 +3,6 @@ drvfail001.hs:16:33:
     No instance for (Show (f (f a)))
       arising from the 'deriving' clause of a data type declaration
     Possible fix:
-      add an instance declaration for (Show (f (f a)))
-      or use a standalone 'deriving instance' declaration,
-           so you can specify the instance context yourself
+      use a standalone 'deriving instance' declaration,
+        so you can specify the instance context yourself
     When deriving the instance for (Show (SM f a))

testsuite/tests/deriving/should_fail/drvfail002.stderr

@@ -2,8 +2,9 @@
 drvfail002.hs:19:23:
     No instance for (X T c)
       arising from the 'deriving' clause of a data type declaration
+    The type variable `c' is ambiguous
+    Possible fix: add a type signature that fixes these type variable(s)
     Possible fix:
-      add an instance declaration for (X T c)
-      or use a standalone 'deriving instance' declaration,
-           so you can specify the instance context yourself
+      use a standalone 'deriving instance' declaration,
+        so you can specify the instance context yourself
     When deriving the instance for (Show S)

testsuite/tests/deriving/should_fail/drvfail003.stderr

@@ -3,7 +3,6 @@ drvfail003.hs:16:56:
     No instance for (Show (v (v a)))
       arising from the 'deriving' clause of a data type declaration
     Possible fix:
-      add an instance declaration for (Show (v (v a)))
-      or use a standalone 'deriving instance' declaration,
-           so you can specify the instance context yourself
+      use a standalone 'deriving instance' declaration,
+        so you can specify the instance context yourself
     When deriving the instance for (Show (Square_ v w a))

testsuite/tests/deriving/should_fail/drvfail004.stderr

@@ -3,7 +3,6 @@ drvfail004.hs:8:12:
     No instance for (Eq (Foo a b))
       arising from the 'deriving' clause of a data type declaration
     Possible fix:
-      add an instance declaration for (Eq (Foo a b))
-      or use a standalone 'deriving instance' declaration,
-           so you can specify the instance context yourself
+      use a standalone 'deriving instance' declaration,
+        so you can specify the instance context yourself
     When deriving the instance for (Ord (Foo a b))

testsuite/tests/deriving/should_fail/drvfail007.stderr

@@ -3,7 +3,6 @@ drvfail007.hs:4:38:
     No instance for (Eq (Int -> Int))
       arising from the 'deriving' clause of a data type declaration
     Possible fix:
-      add an instance declaration for (Eq (Int -> Int))
-      or use a standalone 'deriving instance' declaration,
-           so you can specify the instance context yourself
+      use a standalone 'deriving instance' declaration,
+        so you can specify the instance context yourself
     When deriving the instance for (Eq Foo)

testsuite/tests/deriving/should_fail/drvfail012.stderr

@@ -3,7 +3,6 @@ drvfail012.hs:5:33:
     No instance for (Eq (Ego a))
       arising from the 'deriving' clause of a data type declaration
     Possible fix:
-      add an instance declaration for (Eq (Ego a))
-      or use a standalone 'deriving instance' declaration,
-           so you can specify the instance context yourself
+      use a standalone 'deriving instance' declaration,
+        so you can specify the instance context yourself
     When deriving the instance for (Ord (Ego a))

testsuite/tests/deriving/should_fail/drvfail013.stderr

@@ -3,16 +3,14 @@ drvfail013.hs:4:70:
     No instance for (Eq (m (Maybe a)))
       arising from the 'deriving' clause of a data type declaration
     Possible fix:
-      add an instance declaration for (Eq (m (Maybe a)))
-      or use a standalone 'deriving instance' declaration,
-           so you can specify the instance context yourself
+      use a standalone 'deriving instance' declaration,
+        so you can specify the instance context yourself
     When deriving the instance for (Eq (MaybeT m a))
 
 drvfail013.hs:6:70:
     No instance for (Eq (m (Maybe a)))
       arising from the 'deriving' clause of a data type declaration
     Possible fix:
-      add an instance declaration for (Eq (m (Maybe a)))
-      or use a standalone 'deriving instance' declaration,
-           so you can specify the instance context yourself
+      use a standalone 'deriving instance' declaration,
+        so you can specify the instance context yourself
     When deriving the instance for (Eq (MaybeT' m a))

testsuite/tests/driver/T5147/T5147.stderr

 
 A.hs:6:15:
     No instance for (Show (Fields v)) arising from a use of `show'
-    Possible fix: add an instance declaration for (Show (Fields v))
     In the expression: show a
     In an equation for `showField': showField a = show a

testsuite/tests/gadt/T3169.stderr

@@ -5,6 +5,12 @@ T3169.hs:13:22:
       bound by the instance declaration at T3169.hs:10:10-36
     Expected type: Map a (Map b elt)
       Actual type: Map (a, b) elt
+    Relevant bindings include
+      lookup :: (a, b) -> Map (a, b) elt -> Maybe elt
+        (bound at T3169.hs:12:3)
+      a :: a (bound at T3169.hs:12:11)
+      b :: b (bound at T3169.hs:12:13)
+      m :: Map (a, b) elt (bound at T3169.hs:12:17)
     In the second argument of `lookup', namely `m'
     In the expression: lookup a m :: Maybe (Map b elt)
     In the expression:
@@ -21,6 +27,11 @@ T3169.hs:13:22:
             at T3169.hs:12:3
     Expected type: Map a (Map b elt)
       Actual type: Map (a, b) elt
+    Relevant bindings include
+      lookup :: (a, b) -> Map (a, b) elt -> Maybe elt
+        (bound at T3169.hs:12:3)
+      b :: b (bound at T3169.hs:12:13)
+      m :: Map (a, b) elt (bound at T3169.hs:12:17)
     In the second argument of `lookup', namely `m'
     In the expression: lookup a m :: Maybe (Map b elt)
     In the expression:

testsuite/tests/gadt/rw.stderr

-
-rw.hs:14:47:
-    Couldn't match expected type `a' with actual type `Int'
-      `a' is a rigid type variable bound by
-          the type signature for writeInt :: T a -> IORef a -> IO ()
-          at rw.hs:12:12
-    In the second argument of `writeIORef', namely `(1 :: Int)'
-    In the expression: writeIORef ref (1 :: Int)
-    In a case alternative: ~(Li x) -> writeIORef ref (1 :: Int)
-
-rw.hs:19:51:
-    Couldn't match type `a' with `Bool'
-      `a' is a rigid type variable bound by
-          the type signature for readBool :: T a -> IORef a -> IO ()
-          at rw.hs:16:12
-    Expected type: a -> Bool
-      Actual type: Bool -> Bool
-    In the second argument of `(.)', namely `not'
-    In the second argument of `(>>=)', namely `(print . not)'
-    In the expression: readIORef ref >>= (print . not)
+
+rw.hs:14:47:
+    Couldn't match expected type `a' with actual type `Int'
+      `a' is a rigid type variable bound by
+          the type signature for writeInt :: T a -> IORef a -> IO ()
+          at rw.hs:12:12
+    Relevant bindings include
+      writeInt :: T a -> IORef a -> IO () (bound at rw.hs:13:1)
+      v :: T a (bound at rw.hs:13:10)
+      ref :: IORef a (bound at rw.hs:13:12)
+    In the second argument of `writeIORef', namely `(1 :: Int)'
+    In the expression: writeIORef ref (1 :: Int)
+    In a case alternative: ~(Li x) -> writeIORef ref (1 :: Int)
+
+rw.hs:19:51:
+    Couldn't match type `a' with `Bool'
+      `a' is a rigid type variable bound by
+          the type signature for readBool :: T a -> IORef a -> IO ()
+          at rw.hs:16:12
+    Expected type: a -> Bool
+      Actual type: Bool -> Bool
+    Relevant bindings include
+      readBool :: T a -> IORef a -> IO () (bound at rw.hs:17:1)
+      v :: T a (bound at rw.hs:17:10)
+      ref :: IORef a (bound at rw.hs:17:12)
+    In the second argument of `(.)', namely `not'
+    In the second argument of `(>>=)', namely `(print . not)'
+    In the expression: readIORef ref >>= (print . not)

testsuite/tests/ghci.debugger/scripts/break003.stderr

 
 <interactive>:5:1:
     No instance for (Show (t -> a)) arising from a use of `print'
-    Possible fix: add an instance declaration for (Show (t -> a))
     In a stmt of an interactive GHCi command: print it

testsuite/tests/ghci.debugger/scripts/break006.stderr

@@ -3,6 +3,7 @@
     No instance for (Show a) arising from a use of `print'
     Cannot resolve unknown runtime type `a'
     Use :print or :force to determine these types
+    Relevant bindings include it :: a (bound at <interactive>:6:1)
     Note: there are several potential instances:
       instance Show Double -- Defined in `GHC.Float'
       instance Show Float -- Defined in `GHC.Float'
@@ -15,6 +16,7 @@
     No instance for (Show a) arising from a use of `print'
     Cannot resolve unknown runtime type `a'
     Use :print or :force to determine these types
+    Relevant bindings include it :: a (bound at <interactive>:8:1)
     Note: there are several potential instances:
       instance Show Double -- Defined in `GHC.Float'
       instance Show Float -- Defined in `GHC.Float'