Suggest hiding imports when local definition exists (#2320)

Co-authored-by: Javier Neira <atreyu.bbb@gmail.com>

Author: yoshitsugu

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

@@ -882,8 +882,9 @@ suggestImportDisambiguation df (Just txt) ps@(L _ HsModule {hsmodImports}) fileC
             "Ambiguous occurrence ‘([^’]+)’"
       , Just modules <-
             map last
-                <$> allMatchRegexUnifySpaces _message "imported from ‘([^’]+)’" =
-        suggestions ambiguous modules
+                <$> allMatchRegexUnifySpaces _message "imported from ‘([^’]+)’"
+      , local <- matchRegexUnifySpaces _message "defined at .+:[0-9]+:[0-9]+" =
+        suggestions ambiguous modules (isJust local)
     | otherwise = []
     where
         locDic =
@@ -906,16 +907,16 @@ suggestImportDisambiguation df (Just txt) ps@(L _ HsModule {hsmodImports}) fileC
         -- > removeAllDuplicates [1, 1, 2, 3, 2] = [3]
         removeAllDuplicates = map head . filter ((==1) <$> length) . group . sort
         hasDuplicate xs = length xs /= length (S.fromList xs)
-        suggestions symbol mods
+        suggestions symbol mods local
           | hasDuplicate mods = case mapM toModuleTarget (removeAllDuplicates mods) of
-                                  Just targets -> suggestionsImpl symbol (map (, []) targets)
+                                  Just targets -> suggestionsImpl symbol (map (, []) targets) local
                                   Nothing      -> []
           | otherwise         = case mapM toModuleTarget mods of
-                                  Just targets -> suggestionsImpl symbol (oneAndOthers targets)
+                                  Just targets -> suggestionsImpl symbol (oneAndOthers targets) local
                                   Nothing      -> []
-        suggestionsImpl symbol targetsWithRestImports =
+        suggestionsImpl symbol targetsWithRestImports local =
             sortOn fst
-            [ ( renderUniquify mode modNameText symbol
+            [ ( renderUniquify mode modNameText symbol False
               , disambiguateSymbol ps fileContents diag symbol mode
               )
             | (modTarget, restImports) <- targetsWithRestImports
@@ -942,10 +943,14 @@ suggestImportDisambiguation df (Just txt) ps@(L _ HsModule {hsmodImports}) fileC
                         _                 -> False
                     ]
                 ++ [HideOthers restImports | not (null restImports)]
+            ] ++ [ ( renderUniquify mode T.empty symbol True
+              , disambiguateSymbol ps fileContents diag symbol mode
+              ) | local, not (null targetsWithRestImports)
+                , let mode = HideOthers (uncurry (:) (head targetsWithRestImports))
             ]
-        renderUniquify HideOthers {} modName symbol =
-            "Use " <> modName <> " for " <> symbol <> ", hiding other imports"
-        renderUniquify (ToQualified _ qual) _ symbol =
+        renderUniquify HideOthers {} modName symbol local =
+            "Use " <> (if local then "local definition" else modName) <> " for " <> symbol <> ", hiding other imports"
+        renderUniquify (ToQualified _ qual) _ symbol _ =
             "Replace with qualified: "
                 <> T.pack (moduleNameString qual)
                 <> "."
@@ -1005,7 +1010,6 @@ disambiguateSymbol pm fileContents Diagnostic {..} (T.unpack -> symbol) = \case
                     liftParseAST @RdrName df $
                     prettyPrint $ L (mkGeneralSrcSpan  "") rdr
             ]
-
 findImportDeclByRange :: [LImportDecl GhcPs] -> Range -> Maybe (LImportDecl GhcPs)
 findImportDeclByRange xs range = find (\(L l _)-> srcSpanToRange l == Just range) xs
 

ghcide/test/data/hiding/HideFunctionWithoutLocal.expected.hs

@@ -0,0 +1,14 @@
+module HideFunctionWithoutLocal where
+
+import AVec (fromList)
+import BVec (fromList)
+import CVec hiding ((++), cons)
+import DVec hiding ((++), cons, snoc)
+import EVec as E hiding ((++))
+import Prelude hiding ((++))
+
+theOp = (++)
+
+data Vec a
+
+(++) = undefined

ghcide/test/data/hiding/HideFunctionWithoutLocal.hs

@@ -0,0 +1,13 @@
+module HideFunctionWithoutLocal where
+
+import AVec (fromList)
+import BVec (fromList, (++))
+import CVec hiding (cons)
+import DVec hiding (cons, snoc)
+import EVec as E
+
+theOp = (++)
+
+data Vec a
+
+(++) = undefined

ghcide/test/data/hiding/HidePreludeLocalInfix.expected.hs

@@ -0,0 +1,9 @@
+module HidePreludeLocalInfix where
+import Prelude hiding ((++))
+
+infixed xs ys = xs ++ ys
+
+data Vec a
+
+(++) :: Vec a -> Vec a -> Vec a
+(++) = undefined

ghcide/test/data/hiding/HidePreludeLocalInfix.hs

@@ -0,0 +1,8 @@
+module HidePreludeLocalInfix where
+
+infixed xs ys = xs ++ ys
+
+data Vec a
+
+(++) :: Vec a -> Vec a -> Vec a
+(++) = undefined

ghcide/test/exe/Main.hs

@@ -1798,10 +1798,20 @@ suggestImportDisambiguationTests = testGroup "suggest import disambiguation acti
             compareHideFunctionTo [(8,9),(10,8)]
                 "Use EVec for ++, hiding other imports"
                 "HideFunction.expected.append.E.hs"
+        , testCase "Hide functions without local" $
+            compareTwo
+                "HideFunctionWithoutLocal.hs" [(8,8)]
+                "Use local definition for ++, hiding other imports"
+                "HideFunctionWithoutLocal.expected.hs"
         , testCase "Prelude" $
             compareHideFunctionTo [(8,9),(10,8)]
                 "Use Prelude for ++, hiding other imports"
                 "HideFunction.expected.append.Prelude.hs"
+        , testCase "Prelude and local definition, infix" $
+            compareTwo
+                "HidePreludeLocalInfix.hs" [(2,19)]
+                "Use local definition for ++, hiding other imports"
+                "HidePreludeLocalInfix.expected.hs"
         , testCase "AVec, indented" $
             compareTwo "HidePreludeIndented.hs" [(3,8)]
             "Use AVec for ++, hiding other imports"