More compact rendering of type family injectivity constraints

CHANGELOG.md

@@ -8,6 +8,9 @@
   other cases of rendering of operators. [Issue
   500](https://github.com/tweag/ormolu/issues/500).
 
+* More compact rendering of type family injectivity constraints. [Issue
+  482](https://github.com/tweag/ormolu/issues/482).
+
 ## Ormolu 0.0.3.1
 
 * Fixed rendering of record updates with the record dot preprocessor syntax

data/examples/declaration/type-families/closed-type-family/multi-line-out.hs

@@ -1,7 +1,6 @@
 type family
   Id a =
-    result
-    | result -> a where
+    result | result -> a where
   Id a =
     a
 
@@ -10,8 +9,7 @@ type family
     (a :: k)
     b
     c =
-    foo
-    | foo -> k b where
+    foo | foo -> k b where
   G a b c =
     (a, b)
 

src/Ormolu/Printer/Meat/Declaration/TypeFamily.hs

@@ -11,7 +11,7 @@ where
 
 import BasicTypes (LexicalFixity (..))
 import Control.Monad
-import Data.Maybe (isJust, isNothing)
+import Data.Maybe (isNothing)
 import GHC
 import Ormolu.Printer.Combinators
 import Ormolu.Printer.Meat.Common
@@ -36,11 +36,11 @@ p_famDecl style FamilyDecl {fdTyVars = HsQTvs {..}, ..} = do
         inci
         (p_rdrName fdLName)
         (located' p_hsTyVarBndr <$> hsq_explicit)
-    let rsig = p_familyResultSigL fdResultSig
-    unless (isNothing rsig && isNothing fdInjectivityAnn) space
+    let resultSig = p_familyResultSigL fdResultSig
+    unless (isNothing resultSig && isNothing fdInjectivityAnn) space
     inci $ do
-      sequence_ rsig
-      when (isJust rsig && isJust fdInjectivityAnn) breakpoint
+      sequence_ resultSig
+      space
       forM_ fdInjectivityAnn (located' p_injectivityAnn)
   case mmeqs of
     Nothing -> return ()