Suggest open imports (#740)

Also fixes two bugs with qualified imports

Fixes #480

Author: pepeiborra

src/Development/IDE/Plugin/CodeAction.hs

@@ -311,7 +311,7 @@ suggestExportUnusedTopBinding srcOpt ParsedModule{pm_parsed_source = L _ HsModul
                             $ hsmodDecls
   , Just pos <- _end . getLocatedRange <$> hsmodExports
   , Just needComma <- needsComma source <$> hsmodExports
-  , let exportName = (if needComma then "," else "") <> printExport exportType name 
+  , let exportName = (if needComma then "," else "") <> printExport exportType name
         insertPos = pos {_character = pred $ _character pos}
   = [("Export ‘" <> name <> "’", [TextEdit (Range insertPos insertPos) exportName])]
   | otherwise = []
@@ -833,19 +833,24 @@ suggestNewImport _ _ _ = []
 constructNewImportSuggestions
   :: PackageExportsMap -> NotInScope -> Maybe [T.Text] -> [T.Text]
 constructNewImportSuggestions exportsMap thingMissing notTheseModules = nubOrd
-  [ renderNewImport identInfo m
+  [ suggestion
   | (identInfo, m) <- fromMaybe [] $ Map.lookup name exportsMap
   , canUseIdent thingMissing identInfo
   , m `notElem` fromMaybe [] notTheseModules
+  , suggestion <- renderNewImport identInfo m
   ]
  where
   renderNewImport identInfo m
-    | Just q <- qual = "import qualified " <> m <> " as " <> q
-    | otherwise      = "import " <> m <> " (" <> importWhat identInfo <> ")"
+    | Just q <- qual
+    , asQ <- if q == m then "" else " as " <> q
+    = ["import qualified " <> m <> asQ]
+    | otherwise
+    = ["import " <> m <> " (" <> importWhat identInfo <> ")"
+      ,"import " <> m ]
 
   (qual, name) = case T.splitOn "." (notInScope thingMissing) of
     [n]      -> (Nothing, n)
-    segments -> (Just (T.concat $ init segments), last segments)
+    segments -> (Just (T.intercalate "." $ init segments), last segments)
   importWhat IdentInfo {parent, rendered}
     | Just p <- parent = p <> "(" <> rendered <> ")"
     | otherwise        = rendered

test/exe/Main.hs

@@ -1038,17 +1038,22 @@ suggestImportTests = testGroup "suggest import actions"
     [ test True []          "f = nonEmpty"                []                "import Data.List.NonEmpty (nonEmpty)"
     , test True []          "f = (:|)"                    []                "import Data.List.NonEmpty (NonEmpty((:|)))"
     , test True []          "f :: Natural"                ["f = undefined"] "import Numeric.Natural (Natural)"
+    , test True []          "f :: Natural"                ["f = undefined"] "import Numeric.Natural"
     , test True []          "f :: NonEmpty ()"            ["f = () :| []"]  "import Data.List.NonEmpty (NonEmpty)"
+    , test True []          "f :: NonEmpty ()"            ["f = () :| []"]  "import Data.List.NonEmpty"
     , test True []          "f = First"                   []                "import Data.Monoid (First(First))"
     , test True []          "f = Endo"                    []                "import Data.Monoid (Endo(Endo))"
     , test True []          "f = Version"                 []                "import Data.Version (Version(Version))"
     , test True []          "f ExitSuccess = ()"          []                "import System.Exit (ExitCode(ExitSuccess))"
     , test True []          "f = AssertionFailed"         []                "import Control.Exception (AssertionFailed(AssertionFailed))"
     , test True ["Prelude"] "f = nonEmpty"                []                "import Data.List.NonEmpty (nonEmpty)"
     , test True []          "f :: Alternative f => f ()"  ["f = undefined"] "import Control.Applicative (Alternative)"
+    , test True []          "f :: Alternative f => f ()"  ["f = undefined"] "import Control.Applicative"
     , test True []          "f = empty"                   []                "import Control.Applicative (Alternative(empty))"
+    , test True []          "f = empty"                   []                "import Control.Applicative"
     , test True []          "f = (&)"                     []                "import Data.Function ((&))"
     , test True []          "f = NE.nonEmpty"             []                "import qualified Data.List.NonEmpty as NE"
+    , test True []          "f = Data.List.NonEmpty.nonEmpty" []            "import qualified Data.List.NonEmpty"
     , test True []          "f :: Typeable a => a"        ["f = undefined"] "import Data.Typeable (Typeable)"
     , test True []          "f = pack"                    []                "import Data.Text (pack)"
     , test True []          "f :: Text"                   ["f = undefined"] "import Data.Text (Text)"