comments, fixes

Author: coltenwebb

ghcide/src/Development/IDE/Plugin/Completions.hs

@@ -151,24 +151,23 @@ getCompletionsLSP ide plId
 #endif
             ms <- fmap fst <$> useWithStaleFast GetModSummaryWithoutTimestamps npath
             astres <- case ms of
-              Just ms' -> if uses_overloaded_record_dot ms'
-                then useWithStaleFast GetHieAst npath
-                else return Nothing
-              Nothing -> return Nothing
+              Just ms' | uses_overloaded_record_dot ms'
+                ->  useWithStaleFast GetHieAst npath
+              _ -> return Nothing
 
             pure (opts, fmap (,pm,binds) compls, moduleExports, astres)
         case compls of
           Just (cci', parsedMod, bindMap) -> do
-            pfix <- getCompletionPrefix position cnts
+            let pfix = getCompletionPrefix position cnts
             case (pfix, completionContext) of
-              (Just (PosPrefixInfo _ "" _ _), Just CompletionContext { _triggerCharacter = Just "."})
+              ((PosPrefixInfo _ "" _ _), Just CompletionContext { _triggerCharacter = Just "."})
                 -> return (InL $ List [])
-              (Just pfix', _) -> do
+              (_, _) -> do
                 let clientCaps = clientCapabilities $ shakeExtras ide
                     plugins = idePlugins $ shakeExtras ide
                 config <- getCompletionsConfig plId
 
-                allCompletions <- liftIO $ getCompletions plugins ideOpts cci' parsedMod astres bindMap pfix' clientCaps config moduleExports
+                allCompletions <- liftIO $ getCompletions plugins ideOpts cci' parsedMod astres bindMap pfix clientCaps config moduleExports
                 pure $ InL (List $ orderedCompletions allCompletions)
               _ -> return (InL $ List [])
           _ -> return (InL $ List [])

ghcide/src/Development/IDE/Plugin/Completions/Logic.hs

@@ -21,7 +21,7 @@ import           Data.List.Extra                          as List hiding
 import qualified Data.Map                                 as Map
 
 import           Data.Maybe                               (catMaybes, fromMaybe,
-                                                           isJust, mapMaybe)
+                                                           isJust, mapMaybe, listToMaybe)
 import qualified Data.Text                                as T
 import qualified Text.Fuzzy.Parallel                      as Fuzzy
 
@@ -617,8 +617,10 @@ getCompletions plugins ideOpts CC {allModNamesAsNS, anyQualCompls, unqualCompls,
               in getCContext lpos pm <|> getCContext hpos pm
 
 
-          -- we need the hieast to be fresh
-          -- not fresh, hasfield won't have a chance. it would to another larger change to ghc IfaceTyCon to contain record fields
+          -- We need the hieast to be "fresh". We can't get types from "stale" hie files, so hasfield won't work,
+          -- since it gets the record fields from the types.
+          -- Perhaps this could be fixed with a refactor to GHC's IfaceTyCon, to have it also contain record fields.
+          -- Requiring fresh hieast is fine for normal workflows, because it is generated while the user edits.
           recordDotSyntaxCompls :: [(Bool, CompItem)]
           recordDotSyntaxCompls = case maybe_ast_res of
             Just (HAR {hieAst = hieast, hieKind = HieFresh},_) -> concat $ pointCommand hieast (completionPrefixPos prefixInfo) nodeCompletions
@@ -632,8 +634,12 @@ getCompletions plugins ideOpts CC {allModNamesAsNS, anyQualCompls, unqualCompls,
               getSels :: GHC.TyCon -> [T.Text]
               getSels tycon = let f fieldLabel = printOutputable fieldLabel
                               in map f $ tyConFieldLabels tycon
+              -- Completions can return more information that just the completion itself, but it will
+              -- require more than what GHC currently gives us in the HieAST, since it only gives the Type
+              -- of the fields, not where they are defined, etc. So for now the extra fields remain empty.
+              -- Also: additionalTextEdits is a todo, since we may want to import the record. It requires a way 
+              -- to get the record's module, which isn't included in the type information used to get the fields.
               dotFieldSelectorToCompl :: T.Text -> T.Text -> (Bool, CompItem)
-              --dotFieldSelectorToCompl label = (True, CI CiVariable label (ImportedFrom T.empty) Nothing label Nothing emptySpanDoc False Nothing)
               dotFieldSelectorToCompl recname label = (True, CI
                 { compKind = CiField
                 , insertText = label
@@ -672,11 +678,14 @@ getCompletions plugins ideOpts CC {allModNamesAsNS, anyQualCompls, unqualCompls,
               ty = showForSnippet <$> typ
               thisModName = Local $ nameSrcSpan name
 
+          -- When record-dot-syntax completions are available, we return them exclusively. 
+          -- They are only available when we write i.e. `myrecord.` with OverloadedRecordDot enabled.
+          -- Anything that isn't a field is invalid, so those completion don't make sense.
           compls
-            | T.null prefixScope = map (notQual,) localCompls ++ map (qual,) unqualCompls ++ ((notQual,) . ($ Nothing) <$> anyQualCompls)
+            | T.null prefixScope = map (notQual,) localCompls ++ map (qual,) unqualCompls ++ map (\compl -> (notQual, compl Nothing)) anyQualCompls
             | not $ null recordDotSyntaxCompls = recordDotSyntaxCompls
             | otherwise = ((qual,) <$> Map.findWithDefault [] prefixScope (getQualCompls qualCompls))
-                 ++ ((notQual,) . ($ Just prefixScope) <$> anyQualCompls)
+                 ++ map (\compl -> (notQual, compl (Just prefixScope))) anyQualCompls
 
       filtListWith f list =
         [ fmap f label
@@ -932,19 +941,18 @@ mergeListsBy cmp all_lists = merge_lists all_lists
         [xs]   -> xs
         lists' -> merge_lists lists'
 
-
-getCompletionPrefix :: (Monad m) => Position -> VFS.VirtualFile -> m (Maybe PosPrefixInfo)
+-- |From the given cursor position, gets the prefix module or record for autocompletion
+getCompletionPrefix :: Position -> VFS.VirtualFile -> PosPrefixInfo
 getCompletionPrefix pos@(Position l c) (VFS.VirtualFile _ _ ropetext) =
-      return $ Just $ fromMaybe (PosPrefixInfo "" "" "" pos) $ do -- Maybe monad
-        let headMaybe []    = Nothing
-            headMaybe (x:_) = Just x
-            lastMaybe []     = Nothing
-            lastMaybe [x]    = Just x
-            lastMaybe (_:xs) = lastMaybe xs
+      fromMaybe (PosPrefixInfo "" "" "" pos) $ do -- Maybe monad
+        let headMaybe = listToMaybe
+            lastMaybe = headMaybe . reverse
 
+        -- grab the entire line the cursor is at
         curLine <- headMaybe $ T.lines $ Rope.toText
                              $ fst $ Rope.splitAtLine 1 $ snd $ Rope.splitAtLine (fromIntegral l) ropetext
         let beforePos = T.take (fromIntegral c) curLine
+        -- the word getting typed, after previous space and before cursor
         curWord <-
             if | T.null beforePos        -> Just ""
                | T.last beforePos == ' ' -> Just "" -- don't count abc as the curword in 'abc '

ghcide/src/Development/IDE/Plugin/Completions/Types.hs

@@ -139,7 +139,6 @@ instance Semigroup CachedCompletions where
         CC (a<>a') (b<>b') (c<>c') (d<>d') (e<>e')
 
 
--- moved here from Language.LSP.VFS
 -- | Describes the line at the current cursor position
 data PosPrefixInfo = PosPrefixInfo
   { fullLine    :: !T.Text

test/functional/Completion.hs

@@ -94,11 +94,20 @@ tests = testGroup "completions" [
 
             compls <- getCompletions doc (Position 25 6)
             item <- getCompletionByLabel "a" compls
+
             liftIO $ do
                 item ^. label @?= "a"
-                --item ^. detail @?= Just "Data.List"  TODO
-                --item ^. kind @?= Just CiModule
-            liftIO $ length compls @?= 6
+        , testCase "shows field selectors for nested field" $ runSession hlsCommand fullCaps "test/testdata/completion" $ do
+            doc <- openDoc "RecordDotSyntax.hs" "haskell"
+
+            let te = TextEdit (Range (Position 27 0) (Position 27 8)) "z2 = x.c.z"
+            _ <- applyEdit doc te
+
+            compls <- getCompletions doc (Position 27 9)
+            item <- getCompletionByLabel "z" compls
+
+            liftIO $ do
+                item ^. label @?= "z"
         ]
 
      -- See https://github.com/haskell/haskell-ide-engine/issues/903

test/testdata/completion/RecordDotSyntax.hs

@@ -24,4 +24,5 @@ x = MyRecord1 { a = "Hello", b = 12, c = MyChild { z = "there" } }
 
 y = x.a ++ show x.b 
 
+y2 = x.c.z