Refactor CPP slightly, Add test-cases

src-literatetests/10-tests.blt

@@ -531,6 +531,45 @@ func = if cond
     -- test
     abc
 
+#test nonempty-case-short
+func = case x of
+  False -> False
+  True  -> True
+
+#test nonempty-case-long
+func =
+  case
+      lakjsdlajsdljasdlkjasldjasldjasldjalsdjlaskjd
+        lakjsdlajsdljasdlkjasldjasldjasldjalsdjlaskjd
+    of
+      False -> False
+      True  -> True
+
+#test nonempty-case-long-do
+func = do
+  case
+      lakjsdlajsdljasdlkjasldjasldjasldjalsdjlaskjd
+        lakjsdlajsdljasdlkjasldjasldjasldjalsdjlaskjd
+    of
+      False -> False
+      True  -> True
+
+#test empty-case-short
+func = case x of {}
+
+#test empty-case-long
+func =
+  case
+      lakjsdlajsdljasdlkjasldjasldjasldjalsdjlaskjd
+        lakjsdlajsdljasdlkjasldjasldjasldjalsdjlaskjd
+    of {}
+
+#test empty-case-long-do
+func = do
+  case
+      lakjsdlajsdljasdlkjasldjasldjasldjalsdjlaskjd
+        lakjsdlajsdljasdlkjasldjasldjasldjalsdjlaskjd
+    of {}
 
 ###############################################################################
 ###############################################################################

src/Language/Haskell/Brittany/Internal/Layouters/Expr.hs

@@ -136,6 +136,8 @@ layoutExpr lexpr@(L _ expr) = do
 #if MIN_VERSION_ghc(8,6,0)   /* ghc-8.6 */
     HsLamCase _ XMatchGroup{} ->
       error "brittany internal error: HsLamCase XMatchGroup"
+#endif
+#if MIN_VERSION_ghc(8,6,0)   /* ghc-8.6 */
     HsLamCase _ (MG _ (L _ []) _) -> do
 #elif MIN_VERSION_ghc(8,2,0) /* ghc-8.2 8.4*/
     HsLamCase (MG (L _ []) _ _ _) -> do
@@ -529,18 +531,26 @@ layoutExpr lexpr@(L _ expr) = do
 #if MIN_VERSION_ghc(8,6,0)   /* ghc-8.6 */
     HsCase _ _ XMatchGroup{} ->
       error "brittany internal error: HsCase XMatchGroup"
+#endif
+#if MIN_VERSION_ghc(8,6,0)   /* ghc-8.6 */
     HsCase _ cExp (MG _ (L _ []) _) -> do
 #else
     HsCase cExp (MG (L _ []) _ _ _) -> do
 #endif
       cExpDoc <- docSharedWrapper layoutExpr cExp
-      docSetParSpacing
-        $ docAddBaseY BrIndentRegular
+      docAlt
+        [ docAddBaseY BrIndentRegular
         $ docSeq
             [ appSep $ docLit $ Text.pack "case"
             , appSep $ docForceSingleline cExpDoc
             , docLit $ Text.pack "of {}"
             ]
+        , docPar
+            ( docAddBaseY BrIndentRegular
+            $ docPar (docLit $ Text.pack "case") cExpDoc
+            )
+            (docLit $ Text.pack "of {}")
+        ]
 #if MIN_VERSION_ghc(8,6,0)   /* ghc-8.6 */
     HsCase _ cExp (MG _ lmatches@(L _ matches) _) -> do
 #else