Add record fields to doucment symbols outline (#564)

By collecting the fieldOcc names in the data con args

Author: lukel97

src/Development/IDE/GHC/Compat.hs

@@ -37,6 +37,7 @@ module Development.IDE.GHC.Compat(
     GHC.ModLocation,
     Module.addBootSuffix,
     pattern ModLocation,
+    getConArgs,
 
     module GHC
     ) where
@@ -48,7 +49,12 @@ import Fingerprint (Fingerprint)
 import qualified Module
 
 import qualified GHC
-import GHC hiding (ClassOpSig, DerivD, ForD, IEThingAll, IEThingWith, InstD, TyClD, ValD, ModLocation)
+import GHC hiding (
+      ClassOpSig, DerivD, ForD, IEThingAll, IEThingWith, InstD, TyClD, ValD, ModLocation
+#if MIN_GHC_API_VERSION(8,6,0)
+    , getConArgs
+#endif
+    )
 import qualified HeaderInfo as Hdr
 import Avail
 import ErrUtils (ErrorMessages)
@@ -289,3 +295,10 @@ getModuleHash = mi_mod_hash . mi_final_exts
 #else
 getModuleHash = mi_mod_hash
 #endif
+
+getConArgs :: ConDecl pass -> HsConDeclDetails pass
+#if MIN_GHC_API_VERSION(8,6,0)
+getConArgs = GHC.getConArgs
+#else
+getConArgs = GHC.getConDetails
+#endif

src/Development/IDE/LSP/Outline.hs

@@ -108,11 +108,23 @@ documentSymbolForDecl (L l (TyClD DataDecl { tcdLName = L _ name, tcdDataDefn =
             { _name           = showRdrName n
             , _kind           = SkConstructor
             , _selectionRange = srcSpanToRange l'
+            , _children       = conArgRecordFields (getConArgs x)
             }
         | L l  x <- dd_cons
         , L l' n <- getConNames x
         ]
     }
+  where
+    -- | Extract the record fields of a constructor
+    conArgRecordFields (RecCon (L _ lcdfs)) = Just $ List
+      [ (defDocumentSymbol l :: DocumentSymbol)
+          { _name = showRdrName n
+          , _kind = SkField
+          }
+      | L _ cdf <- lcdfs
+      , L l n <- rdrNameFieldOcc . unLoc <$> cd_fld_names cdf
+      ]
+    conArgRecordFields _ = Nothing
 documentSymbolForDecl (L l (TyClD SynDecl { tcdLName = L l' n })) = Just
   (defDocumentSymbol l :: DocumentSymbol) { _name           = showRdrName n
                                           , _kind           = SkTypeParameter

test/exe/Main.hs

@@ -1853,6 +1853,18 @@ outlineTests = testGroup
                               (R 0 0 0 10)
                               [docSymbol "C" SkConstructor (R 0 9 0 10)]
       ]
+  , testSessionWait "record fields" $ do
+    let source = T.unlines ["data A = B {", "  x :: Int", "  , y :: Int}"]
+    docId   <- createDoc "A.hs" "haskell" source
+    symbols <- getDocumentSymbols docId
+    liftIO $ symbols @=? Left
+      [ docSymbolWithChildren "A" SkStruct (R 0 0 2 13)
+          [ docSymbolWithChildren' "B" SkConstructor (R 0 9 2 13) (R 0 9 0 10)
+            [ docSymbol "x" SkField (R 1 2 1 3)
+            , docSymbol "y" SkField (R 2 4 2 5)
+            ]
+          ]
+      ]
   , testSessionWait "import" $ do
     let source = T.unlines ["import Data.Maybe"]
     docId   <- createDoc "A.hs" "haskell" source
@@ -1902,6 +1914,8 @@ outlineTests = testGroup
     DocumentSymbol name (Just detail) kind Nothing loc loc Nothing
   docSymbolWithChildren name kind loc cc =
     DocumentSymbol name Nothing kind Nothing loc loc (Just $ List cc)
+  docSymbolWithChildren' name kind loc selectionLoc cc =
+    DocumentSymbol name Nothing kind Nothing loc selectionLoc (Just $ List cc)
   moduleSymbol name loc cc = DocumentSymbol name
                                             Nothing
                                             SkFile