Fix wrong extend import while type constuctor and data constructor have the same name (#1775)

* Fix wrong extend import while type constuctor and data constructor have the same name

* Add description of sortedMatch

Author: July541

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

@@ -768,7 +768,7 @@ suggestExtendImport exportsMap (L _ HsModule {hsmodImports}) Diagnostic{_range=_
     | otherwise = []
     where
         suggestions decls binding mod srcspan
-          |  range <- case [ x | (x,"") <- readSrcSpan (T.unpack srcspan)] of
+          | range <- case [ x | (x,"") <- readSrcSpan (T.unpack srcspan)] of
                 [s] -> let x = realSrcSpanToRange s
                    in x{_end = (_end x){_character = succ (_character (_end x))}}
                 _ -> error "bug in srcspan parser",
@@ -783,8 +783,13 @@ suggestExtendImport exportsMap (L _ HsModule {hsmodImports}) Diagnostic{_range=_
           | otherwise = []
         lookupExportMap binding mod
           | Just match <- Map.lookup binding (getExportsMap exportsMap)
-          , [ident] <- filter (\ident -> moduleNameText ident == mod) (Set.toList match)
-           = Just ident
+          -- Only for the situation that data constructor name is same as type constructor name,
+          -- let ident with parent be in front of the one without.
+          , sortedMatch <- sortBy (\ident1 ident2 -> parent ident2 `compare` parent ident1) (Set.toList match)
+          , idents <- filter (\ident -> moduleNameText ident == mod) sortedMatch
+          , (not . null) idents -- Ensure fallback while `idents` is empty
+          , ident <- head idents
+          = Just ident
 
             -- fallback to using GHC suggestion even though it is not always correct
           | otherwise

ghcide/test/exe/Main.hs

@@ -1408,6 +1408,25 @@ extendImportTests = testGroup "extend import actions"
                     , "import A (pattern Some)"
                     , "k (Some x) = x"
                     ])
+        , testSession "type constructor name same as data constructor name" $ template
+            [("ModuleA.hs", T.unlines
+                    [ "module ModuleA where"
+                    , "newtype Foo = Foo Int"
+                    ])]
+            ("ModuleB.hs", T.unlines
+                    [ "module ModuleB where"
+                    , "import ModuleA(Foo)"
+                    , "f :: Foo"
+                    , "f = Foo 1"
+                    ])
+            (Range (Position 3 4) (Position 3 6))
+            ["Add Foo(Foo) to the import list of ModuleA"]
+            (T.unlines
+                    [ "module ModuleB where"
+                    , "import ModuleA(Foo (Foo))"
+                    , "f :: Foo"
+                    , "f = Foo 1"
+                    ])
         ]
       where
         codeActionTitle CodeAction{_title=x} = x