Use single-line layout for parens around single-line content

CHANGELOG.md

@@ -1,3 +1,8 @@
+## Unreleased
+
+* Use single-line layout for parens around single-line content. [Issue
+  1120](https://github.com/tweag/ormolu/issues/1120).
+
 ## Ormolu 0.7.6.0
 
 * Fix Haddock comments on infix constructors

data/examples/declaration/signature/specialize/specialize-instance-out.hs

@@ -8,7 +8,6 @@ instance (Eq a) => Eq (Foo a) where
 
 instance (Num r, V.Vector v r, Factored m r) => Num (VT v m r) where
   {-# SPECIALIZE instance
-    ( (Factored m Int) => Num (VT U.Vector m Int)
-    )
+    ((Factored m Int) => Num (VT U.Vector m Int))
     #-}
   VT x + VT y = VT $ V.zipWith (+) x y

data/examples/declaration/splice/typed-splice-out.hs

@@ -1,7 +1,6 @@
 {-# LANGUAGE TemplateHaskell #-}
 
 x =
-  $$( foo bar
-    )
+  $$(foo bar)
 
 x = $$foo

data/examples/declaration/type/parens-comments-out.hs

@@ -0,0 +1,4 @@
+type Test =
+  ( -- a
+    x
+  )

data/examples/declaration/type/parens-comments.hs

@@ -0,0 +1,3 @@
+type Test = (
+  -- a
+  x)

data/examples/declaration/value/function/application-2-out.hs

@@ -1,13 +1,11 @@
 {-# LANGUAGE TemplateHaskell #-}
 
 foo = do
-  $( bar
-   )
+  $(bar)
     baz
 
 foo = do
-  $$( bar
-    )
+  $$(bar)
     baz
 
 foo = do

data/examples/declaration/value/function/arrow/proc-parentheses-out.hs

@@ -4,8 +4,7 @@ foo f = proc a -> (f -< a)
 
 bar f g = proc a ->
   ( ( (f)
-        ( g
-        )
+        (g)
     )
       -<
         ( ( ( ( ( ( g

data/examples/declaration/value/function/parens-comments-out.hs

@@ -0,0 +1,4 @@
+test =
+  ( -- a
+    x
+  )

data/examples/declaration/value/function/parens-comments.hs

@@ -0,0 +1,3 @@
+test = (
+  -- a
+  x)

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

@@ -49,8 +49,7 @@ p_classDecl ctx name HsQTvs {..} fixity fdeps csigs cdefs cats catdefs cdocs = d
       tyFams = (getLocA &&& fmap (TyClD NoExtField . FamDecl NoExtField)) <$> cats
       docs = (getLocA &&& fmap (DocD NoExtField)) <$> cdocs
       tyFamDefs =
-        ( getLocA &&& fmap (InstD NoExtField . TyFamInstD NoExtField)
-        )
+        (getLocA &&& fmap (InstD NoExtField . TyFamInstD NoExtField))
           <$> catdefs
       allDecls =
         snd <$> sortBy (leftmost_smallest `on` fst) (sigs <> vals <> tyFams <> tyFamDefs <> docs)

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

@@ -70,12 +70,10 @@ p_clsInstDecl ClsInstDecl {cid_ext = (mWarnTxt, _, _), ..} = do
   let sigs = (getLocA &&& fmap (SigD NoExtField)) <$> cid_sigs
       vals = (getLocA &&& fmap (ValD NoExtField)) <$> toList cid_binds
       tyFamInsts =
-        ( getLocA &&& fmap (InstD NoExtField . TyFamInstD NoExtField)
-        )
+        (getLocA &&& fmap (InstD NoExtField . TyFamInstD NoExtField))
           <$> cid_tyfam_insts
       dataFamInsts =
-        ( getLocA &&& fmap (InstD NoExtField . DataFamInstD NoExtField)
-        )
+        (getLocA &&& fmap (InstD NoExtField . DataFamInstD NoExtField))
           <$> cid_datafam_insts
       allDecls =
         snd <$> sortBy (leftmost_smallest `on` fst) (sigs <> vals <> tyFamInsts <> dataFamInsts)

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

@@ -696,8 +696,11 @@ p_hsExpr' isApp s = \case
     -- negated literals, as `- 1` and `-1` have differing AST.
     when (negativeLiterals && isLiteral) space
     located e p_hsExpr
-  HsPar _ e ->
-    parens s (located e (dontUseBraces . p_hsExpr))
+  HsPar _ e -> do
+    csSpans <-
+      fmap (flip RealSrcSpan Strict.Nothing . getLoc) <$> getEnclosingComments
+    switchLayout (locA e : csSpans) $
+      parens s (located e (dontUseBraces . p_hsExpr))
   SectionL _ x op -> do
     located x p_hsExpr
     breakpoint

src/Ormolu/Printer/Meat/Type.hs

@@ -22,6 +22,7 @@ module Ormolu.Printer.Meat.Type
 where
 
 import Data.Choice (pattern With)
+import GHC.Data.Strict qualified as Strict
 import GHC.Hs hiding (isPromoted)
 import GHC.Types.SourceText
 import GHC.Types.SrcLoc
@@ -117,8 +118,11 @@ p_hsType' multilineArgs = \case
     let opTree = BinaryOpBranches (tyOpTree x) op (tyOpTree y)
     p_tyOpTree
       (reassociateOpTree debug (Just . unLoc) modFixityMap opTree)
-  HsParTy _ t ->
-    parens N (located t p_hsType)
+  HsParTy _ t -> do
+    csSpans <-
+      fmap (flip RealSrcSpan Strict.Nothing . getLoc) <$> getEnclosingComments
+    switchLayout (locA t : csSpans) $
+      parens N (located t p_hsType)
   HsIParamTy _ n t -> sitcc $ do
     located n atom
     space