Follow change in typechecker error messages

testsuite/tests/ghc-regress/indexed-types/should_fail/T4093a.stderr

-
-T4093a.hs:8:8:
-    Couldn't match type `e' with `()'
-      `e' is a rigid type variable bound by
-          the type signature for `hang' at T4093a.hs:7:14
-    In the expression: Just ()
-    In an equation for `hang': hang = Just ()
+
+T4093a.hs:8:8:
+    Could not deduce (e ~ ()) from the context (Foo e ~ Maybe e)
+      `e' is a rigid type variable bound by
+          the type signature for `hang' at T4093a.hs:7:14
+    In the expression: Just ()
+    In an equation for `hang': hang = Just ()

testsuite/tests/ghc-regress/indexed-types/should_fail/T4093b.stderr

 
 T4093b.hs:31:13:
-    Couldn't match type `e' with `C'
+    Could not deduce (e ~ C)
+      from the context (EitherCO e (A C O n) (A O O n) ~ A e O n,
+                        EitherCO x (A C C n) (A C O n) ~ A C x n)
       `e' is a rigid type variable bound by
           the type signature for `blockToNodeList' at T4093b.hs:20:12
     In the expression: (JustC n, NothingC)

testsuite/tests/ghc-regress/indexed-types/should_fail/T4254.stderr

-
-T4254.hs:19:10:
-    Couldn't match type `b' with `Bool'
-      `b' is a rigid type variable bound by
-          the type signature for `fails' at T4254.hs:18:19
-    In the expression: op
-    In an equation for `fails': fails = op
+
+T4254.hs:19:10:
+    Could not deduce (b ~ Bool) from the context (a ~ Int, FD a b)
+      `b' is a rigid type variable bound by
+          the type signature for `fails' at T4254.hs:18:19
+    In the expression: op
+    In an equation for `fails': fails = op

testsuite/tests/ghc-regress/typecheck/should_compile/FD1.stderr

 
 FD1.hs:16:1:
-    Couldn't match type `a' with `Int -> Int'
+    Could not deduce (a ~ (Int -> Int))
+      from the context (E a (Int -> Int))
       `a' is a rigid type variable bound by
           the type signature for `plus' at FD1.hs:15:12
     The equation(s) for `plus' have two arguments,

testsuite/tests/ghc-regress/typecheck/should_compile/FD2.stderr

 
 FD2.hs:26:34:
-    Couldn't match type `e' with `e1'
+    Could not deduce (e ~ e1)
+      from the context (Foldable a, Elem a e, Elem a e1)
       `e' is a rigid type variable bound by
           the type signature for `foldr1' at FD2.hs:21:20
       `e1' is a rigid type variable bound by

testsuite/tests/ghc-regress/typecheck/should_compile/T2494.stderr

@@ -10,7 +10,7 @@ T2494.hs:15:14:
     In the expression: foo f (foo g x)
 
 T2494.hs:15:30:
-    Couldn't match type `b' with `a'
+    Could not deduce (b ~ a) from the context (Monad m)
       `b' is a rigid type variable bound by
           the type signature for `g' at T2494.hs:14:46
       `a' is a rigid type variable bound by

testsuite/tests/ghc-regress/typecheck/should_fail/T2688.stderr

 
 T2688.hs:8:22:
-    Couldn't match type `s' with `v'
+    Could not deduce (s ~ v) from the context (VectorSpace v s)
       `s' is a rigid type variable bound by
           the class declaration for `VectorSpace' at T2688.hs:5:21
       `v' is a rigid type variable bound by

testsuite/tests/ghc-regress/typecheck/should_fail/tcfail068.stderr

 
 tcfail068.hs:14:9:
-    Couldn't match type `s1' with `s'
+    Could not deduce (s1 ~ s) from the context (Constructed a)
       `s1' is a rigid type variable bound by
            the polymorphic type `forall s. GHC.ST.ST s a' at tcfail068.hs:13:9
       `s' is a rigid type variable bound by
           the type signature for `itgen' at tcfail068.hs:11:53
     In the first argument of `runST', namely
-        `(newSTArray ((1, 1), n) x)'
+      `(newSTArray ((1, 1), n) x)'
     In the expression: runST (newSTArray ((1, 1), n) x)
     In an equation for `itgen':
         itgen n x = runST (newSTArray ((1, 1), n) x)
 
 tcfail068.hs:19:21:
-    Couldn't match type `s' with `s1'
+    Could not deduce (s ~ s1) from the context (Constructed a)
       `s' is a rigid type variable bound by
           the type signature for `itiap' at tcfail068.hs:16:58
       `s1' is a rigid type variable bound by
@@ -20,12 +20,12 @@ tcfail068.hs:19:21:
     In the first argument of `readSTArray', namely `arr'
     In the first argument of `(>>=)', namely `readSTArray arr i'
     In the first argument of `runST', namely
-        `(readSTArray arr i
-        >>=
-          \ val -> writeSTArray arr i (f val) >> return arr)'
+      `(readSTArray arr i
+      >>=
+        \ val -> writeSTArray arr i (f val) >> return arr)'
 
 tcfail068.hs:24:35:
-    Couldn't match type `s' with `s1'
+    Could not deduce (s ~ s1) from the context (Constructed a)
       `s' is a rigid type variable bound by
           the type signature for `itrap' at tcfail068.hs:23:70
       `s1' is a rigid type variable bound by
@@ -35,18 +35,18 @@ tcfail068.hs:24:35:
     In the expression: runST (itrap' i k)
     In an equation for `itrap':
         itrap ((i, k), (j, l)) f arr
-                = runST (itrap' i k)
-                where
-                    itrap' i k
-                             = if k > l then return arr else (itrapsnd i k >> itrap' i (k + 1))
-                    itrapsnd i k
-                               = if i > j then
-                                     return arr
-                                 else
-                                     (readSTArray arr (i, k) >>= \ val -> ...)
+          = runST (itrap' i k)
+          where
+              itrap' i k
+                = if k > l then return arr else (itrapsnd i k >> itrap' i (k + 1))
+              itrapsnd i k
+                = if i > j then
+                      return arr
+                  else
+                      (readSTArray arr (i, k) >>= \ val -> ...)
 
 tcfail068.hs:36:46:
-    Couldn't match type `s' with `s1'
+    Could not deduce (s ~ s1) from the context (Constructed b)
       `s' is a rigid type variable bound by
           the type signature for `itrapstate' at tcfail068.hs:35:40
       `s1' is a rigid type variable bound by
@@ -56,15 +56,15 @@ tcfail068.hs:36:46:
     In the expression: runST (itrapstate' i k s)
     In an equation for `itrapstate':
         itrapstate ((i, k), (j, l)) f c d s arr
-                     = runST (itrapstate' i k s)
-                     where
-                         itrapstate' i k s
-                                       = if k > l then
-                                             return (s, arr)
-                                         else
-                                             (itrapstatesnd i k s >>= \ (s, arr) -> ...)
-                         itrapstatesnd i k s
-                                         = if i > j then
-                                               return (s, arr)
-                                           else
-                                               (readSTArray arr (i, k) >>= \ val -> ...)
+          = runST (itrapstate' i k s)
+          where
+              itrapstate' i k s
+                = if k > l then
+                      return (s, arr)
+                  else
+                      (itrapstatesnd i k s >>= \ (s, arr) -> ...)
+              itrapstatesnd i k s
+                = if i > j then
+                      return (s, arr)
+                  else
+                      (readSTArray arr (i, k) >>= \ val -> ...)

testsuite/tests/ghc-regress/typecheck/should_fail/tcfail131.stderr

 
 tcfail131.hs:7:9:
-    Couldn't match type `b' with `Integer'
+    Could not deduce (b ~ Integer) from the context (Num b)
       `b' is a rigid type variable bound by
           the type signature for `g' at tcfail131.hs:6:12
     In the expression: f x x