Add test for empty cases; update output for braces in HsCase printing

All to support Trac #2431

testsuite/tests/ghc-regress/gadt/gadt-escape1.stderr

@@ -4,6 +4,6 @@ gadt-escape1.hs:16:52:
       Solution: add a type signature
     In a case alternative: Hidden (ExpInt _) a -> a
     In the expression:
-        case (hval :: Hidden) of Hidden (ExpInt _) a -> a
+        case (hval :: Hidden) of { Hidden (ExpInt _) a -> a }
     In the definition of `weird1':
-        weird1 = case (hval :: Hidden) of Hidden (ExpInt _) a -> a
+        weird1 = case (hval :: Hidden) of { Hidden (ExpInt _) a -> a }

testsuite/tests/ghc-regress/gadt/gadt7.stderr

@@ -4,11 +4,11 @@ gadt7.hs:12:31:
       Solution: add a type signature
     In the pattern: K
     In a case alternative: K -> y1
-    In the expression: case t1 of K -> y1
+    In the expression: case t1 of { K -> y1 }
 
 gadt7.hs:15:32:
     GADT pattern match in non-rigid context for `K'
       Solution: add a type signature
     In the pattern: K
     In a case alternative: K -> y1
-    In the expression: case t1 of K -> y1
+    In the expression: case t1 of { K -> y1 }

testsuite/tests/ghc-regress/indexed-types/should_fail/GADTwrong1.stderr

@@ -7,4 +7,4 @@ GADTwrong1.hs:12:18:
            the constructor `T' at GADTwrong1.hs:12:11
     In the expression: y
     In a case alternative: T y -> y
-    In the expression: case T x :: T (Const b) of T y -> y
+    In the expression: case T x :: T (Const b) of { T y -> y }

testsuite/tests/ghc-regress/th/TH_emptycase.hs

+{-# LANGUAGE TemplateHaskell #-}
+-- Trac #2431: empty case expression
+
+module Main where
+
+import Language.Haskell.TH
+
+f :: Int
+f = $(caseE (litE $ CharL 'a') [])
+
+main = print f

testsuite/tests/ghc-regress/th/TH_emptycase.stderr

+TH_emptycase: TH_emptycase.hs:9:4-33: Non-exhaustive patterns in case
+

testsuite/tests/ghc-regress/th/TH_exn1.stderr

@@ -4,6 +4,6 @@ TH_exn1.hs:1:0:
       TH_exn1.hs:(9,3)-(10,15): Non-exhaustive patterns in case
 
       Code: let
-	      return = return
-	      $dMonad = Language.Haskell.TH.Syntax.$f22
-	    in case reverse "no" of [] -> return (GHC.Types.[])
+              return = return
+              $dMonad = Language.Haskell.TH.Syntax.$f22
+            in case reverse "no" of { [] -> return (GHC.Types.[]) }

testsuite/tests/ghc-regress/th/all.T

@@ -105,3 +105,4 @@ test('TH_scope', normal, compile, [''])
 test('T2386', extra_clean(['T2386_Lib.hi', 'T2386_Lib.o']),
 	      run_command,
 	      ['$MAKE -s --no-print-directory T2386'] )
+test('TH_emptycase', exit_code(1), compile_and_run, [''])

testsuite/tests/ghc-regress/typecheck/should_fail/tcfail069.stderr

 
 tcfail069.hs:21:6:
     Couldn't match expected type `([Int], [Int])'
-	   against inferred type `[a]'
+           against inferred type `[a]'
     In the pattern: []
     In a case alternative: [] -> error "foo"
-    In the expression: case (list1, list2) of [] -> error "foo"
+    In the expression: case (list1, list2) of { [] -> error "foo" }

testsuite/tests/ghc-regress/typecheck/should_fail/tcfail115.stderr

@@ -9,5 +9,5 @@ tcfail115.hs:9:23:
 tcfail115.hs:12:24:
     The variable `r' cannot be bound to an unboxed tuple
     In a case alternative: r -> r
-    In the expression: case t x of r -> r
-    In the expression: \ x -> case t x of r -> r
+    In the expression: case t x of { r -> r }
+    In the expression: \ x -> case t x of { r -> r }

testsuite/tests/ghc-regress/typecheck/should_fail/tcfail120.stderr

@@ -3,4 +3,4 @@ tcfail120.hs:13:25:
     A wild-card pattern cannot be bound to an unboxed tuple
     In the pattern: _
     In a case alternative: _ -> (# 3, 4 #)
-    In the expression: case t x of _ -> (# 3, 4 #)
+    In the expression: case t x of { _ -> (# 3, 4 #) }

testsuite/tests/ghc-regress/typecheck/should_fail/tcfail180.stderr

@@ -3,4 +3,4 @@ tcfail180.hs:10:8:
     Couldn't match expected type `f b' against inferred type `Bool'
     In the pattern: True
     In a case alternative: True -> ()
-    In the expression: case p of True -> ()
+    In the expression: case p of { True -> () }

testsuite/tests/ghc-regress/typecheck/should_fail/tcfail201.stderr

@@ -6,6 +6,6 @@ tcfail201.hs:17:5:
     In the pattern: DocEmpty
     In a case alternative: DocEmpty -> z DocEmpty
     In the expression:
-        case hsDoc of
+        case hsDoc of {
           DocEmpty -> z DocEmpty
-          (DocParagraph hsDoc) -> z DocParagraph `k` hsDoc
+          (DocParagraph hsDoc) -> z DocParagraph `k` hsDoc }