Support rendering of role annotation declarations

data/examples/declaration/role-annotation/simple-out.hs

@@ -0,0 +1,25 @@
+{-# LANGUAGE RoleAnnotations #-}
+{-# LANGUAGE MagicHash #-}
+type role Ptr representational
+
+type role A nominal nominal
+
+type role B _ phantom
+
+type role C _ _
+
+type role
+  D
+    phantom
+    nominal
+
+type role
+  E
+    _
+    nominal
+
+type role
+  E
+    _
+    nominal
+    phantom

data/examples/declaration/role-annotation/simple.hs

@@ -0,0 +1,25 @@
+{-# LANGUAGE RoleAnnotations #-}
+{-# LANGUAGE MagicHash #-}
+
+type role Ptr representational
+
+type role A nominal nominal
+
+type role B _ phantom
+type role C _ _
+
+type role
+  D phantom nominal
+
+type
+  role
+    E
+      _
+    nominal
+
+type
+    role
+      E
+        _
+      nominal
+    phantom

ormolu.cabal

@@ -61,8 +61,9 @@ library
                     , Ormolu.Printer.Meat.Common
                     , Ormolu.Printer.Meat.Declaration
                     , Ormolu.Printer.Meat.Declaration.Class
-                    , Ormolu.Printer.Meat.Declaration.Instance
                     , Ormolu.Printer.Meat.Declaration.Data
+                    , Ormolu.Printer.Meat.Declaration.Instance
+                    , Ormolu.Printer.Meat.Declaration.RoleAnnotation
                     , Ormolu.Printer.Meat.Declaration.Signature
                     , Ormolu.Printer.Meat.Declaration.Type
                     , Ormolu.Printer.Meat.Declaration.TypeFamily

src/Ormolu/Printer/Meat/Declaration.hs

@@ -10,10 +10,11 @@ where
 
 import GHC
 import Ormolu.Printer.Combinators
-import Ormolu.Printer.Meat.Declaration.Class
 import Ormolu.Printer.Meat.Common
+import Ormolu.Printer.Meat.Declaration.Class
 import Ormolu.Printer.Meat.Declaration.Data
 import Ormolu.Printer.Meat.Declaration.Instance
+import Ormolu.Printer.Meat.Declaration.RoleAnnotation
 import Ormolu.Printer.Meat.Declaration.Signature
 import Ormolu.Printer.Meat.Declaration.Type
 import Ormolu.Printer.Meat.Declaration.TypeFamily
@@ -35,7 +36,7 @@ p_hsDecl = \case
   RuleD _ _ -> notImplemented "RuleD"
   SpliceD _ _ -> notImplemented "SpliceD"
   DocD _ _ -> notImplemented "DocD"
-  RoleAnnotD _ _ -> notImplemented "RoleAnnotD"
+  RoleAnnotD NoExt x -> p_roleAnnot x
   XHsDecl _ -> notImplemented "XHsDecl"
 
 p_tyClDecl :: TyClDecl GhcPs -> R ()

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

@@ -0,0 +1,41 @@
+{-# LANGUAGE LambdaCase        #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE RecordWildCards   #-}
+{-# LANGUAGE TypeFamilies #-}
+
+-- | Rendering of Role annotation declarations.
+
+module Ormolu.Printer.Meat.Declaration.RoleAnnotation
+  ( p_roleAnnot
+  )
+where
+
+import CoAxiom
+import GHC
+import Ormolu.Printer.Combinators
+import Ormolu.Printer.Meat.Common
+import Ormolu.Utils
+import RdrName (RdrName (..))
+import SrcLoc (Located)
+
+p_roleAnnot :: RoleAnnotDecl GhcPs -> R ()
+p_roleAnnot = \case
+  RoleAnnotDecl NoExt l_name anns -> p_roleAnnot' l_name anns
+  XRoleAnnotDecl _ -> notImplemented "XRoleAnnotDecl"
+
+p_roleAnnot' :: Located RdrName -> [Located (Maybe Role)] -> R ()
+p_roleAnnot' l_name anns = line $ do
+  txt "type role"
+  breakpoint
+  inci $ do
+    p_rdrName l_name
+    breakpoint
+    let
+      p_role' = maybe (txt "_") p_role
+    inci $ velt' $ (located' p_role') <$> anns
+
+p_role :: Role -> R ()
+p_role = \case
+  Nominal -> txt "nominal"
+  Representational -> txt "representational"
+  Phantom -> txt "phantom"