From c90fd07ffbbc1deb15f4a426bcd3a4bf0c7dee7a Mon Sep 17 00:00:00 2001
From: Potato Hatsue <1793913507@qq.com>
Date: Sun, 21 Feb 2021 13:17:21 +0800
Subject: [PATCH 1/9] Refactor pragmas plugin

---
 .../src/Development/IDE/Plugin/CodeAction.hs  |  23 --
 ghcide/test/exe/Main.hs                       | 112 ++------
 plugins/default/src/Ide/Plugin/Pragmas.hs     | 268 ++++++++++--------
 test/functional/Class.hs                      |   1 -
 test/functional/FunctionalCodeAction.hs       |  61 +++-
 5 files changed, 236 insertions(+), 229 deletions(-)

diff --git a/ghcide/src/Development/IDE/Plugin/CodeAction.hs b/ghcide/src/Development/IDE/Plugin/CodeAction.hs
index 3ee947af84..8d93479b66 100644
--- a/ghcide/src/Development/IDE/Plugin/CodeAction.hs
+++ b/ghcide/src/Development/IDE/Plugin/CodeAction.hs
@@ -158,7 +158,6 @@ suggestAction packageExports ideOptions parsedModule text df annSource tcM har d
     ++ suggestNewImport packageExports pm diag
     ++ suggestDeleteUnusedBinding pm text diag
     ++ suggestExportUnusedTopBinding text pm diag
-    ++ suggestDisableWarning pm text diag
     | Just pm <- [parsedModule]
     ] ++
     suggestFillHole diag                   -- Lowest priority
@@ -257,15 +256,6 @@ isUnusedImportedId
       maybe True (not . any (\(_, IdentifierDetails {..}) -> identInfo == S.singleton Use)) refs
     | otherwise = False
 
-suggestDisableWarning :: ParsedModule -> Maybe T.Text -> Diagnostic -> [(T.Text, [TextEdit])]
-suggestDisableWarning pm contents Diagnostic{..}
-    | Just (InR (T.stripPrefix "-W" -> Just w)) <- _code =
-        pure
-            ( "Disable \"" <> w <> "\" warnings"
-            , [TextEdit (endOfModuleHeader pm contents) $ "{-# OPTIONS_GHC -Wno-" <> w <> " #-}\n"]
-            )
-    | otherwise = []
-
 suggestRemoveRedundantImport :: ParsedModule -> Maybe T.Text -> Diagnostic -> [(T.Text, [TextEdit])]
 suggestRemoveRedundantImport ParsedModule{pm_parsed_source = L _  HsModule{hsmodImports}} contents Diagnostic{_range=_range,..}
 --     The qualified import of ‘many’ from module ‘Control.Applicative’ is redundant
@@ -1452,16 +1442,3 @@ renderImportStyle :: ImportStyle -> T.Text
 renderImportStyle (ImportTopLevel x) = x
 renderImportStyle (ImportViaParent x p) = p <> "(" <> x <> ")"
 
--- | Find the first non-blank line before the first of (module name / imports / declarations).
--- Useful for inserting pragmas.
-endOfModuleHeader :: ParsedModule -> Maybe T.Text -> Range
-endOfModuleHeader pm contents =
-    let mod = unLoc $ pm_parsed_source pm
-        modNameLoc = getLoc <$> hsmodName mod
-        firstImportLoc = getLoc <$> listToMaybe (hsmodImports mod)
-        firstDeclLoc = getLoc <$> listToMaybe (hsmodDecls mod)
-        line = fromMaybe 0 $ firstNonBlankBefore . _line . _start =<< srcSpanToRange =<<
-            modNameLoc <|> firstImportLoc <|> firstDeclLoc
-        firstNonBlankBefore n = (n -) . fromMaybe 0 . findIndex (not . T.null) . reverse . take n . T.lines <$> contents
-        loc = Position line 0
-     in Range loc loc
diff --git a/ghcide/test/exe/Main.hs b/ghcide/test/exe/Main.hs
index 4c15476bf8..0cfb5c7e56 100644
--- a/ghcide/test/exe/Main.hs
+++ b/ghcide/test/exe/Main.hs
@@ -81,7 +81,6 @@ import Development.IDE.Plugin.Test (TestRequest (BlockSeconds, GetInterfaceFiles
 import Control.Monad.Extra (whenJust)
 import qualified Language.LSP.Types.Lens as L
 import Control.Lens ((^.))
-import Data.Functor
 import Data.Tuple.Extra
 
 waitForProgressBegin :: Session ()
@@ -706,7 +705,6 @@ codeActionTests = testGroup "code actions"
   , suggestImportTests
   , suggestHideShadowTests
   , suggestImportDisambiguationTests
-  , disableWarningTests
   , fixConstructorImportTests
   , importRenameActionTests
   , fillTypedHoleTests
@@ -913,8 +911,9 @@ removeImportTests = testGroup "remove import actions"
             ]
       docB <- createDoc "ModuleB.hs" "haskell" contentB
       _ <- waitForDiagnostics
-      action <- assertJust "Code action not found" . firstJust (caWithTitle "Remove import")
-        =<< getCodeActions docB (Range (Position 2 0) (Position 2 5))
+      [InR action@CodeAction { _title = actionTitle }, _]
+          <- getCodeActions docB (Range (Position 2 0) (Position 2 5))
+      liftIO $ "Remove import" @=? actionTitle
       executeCodeAction action
       contentAfterAction <- documentContents docB
       let expectedContentAfterAction = T.unlines
@@ -938,8 +937,9 @@ removeImportTests = testGroup "remove import actions"
             ]
       docB <- createDoc "ModuleB.hs" "haskell" contentB
       _ <- waitForDiagnostics
-      action <- assertJust "Code action not found" . firstJust (caWithTitle "Remove import")
-        =<< getCodeActions docB (Range (Position 2 0) (Position 2 5))
+      [InR action@CodeAction { _title = actionTitle }, _]
+          <- getCodeActions docB (Range (Position 2 0) (Position 2 5))
+      liftIO $ "Remove import" @=? actionTitle
       executeCodeAction action
       contentAfterAction <- documentContents docB
       let expectedContentAfterAction = T.unlines
@@ -966,8 +966,9 @@ removeImportTests = testGroup "remove import actions"
             ]
       docB <- createDoc "ModuleB.hs" "haskell" contentB
       _ <- waitForDiagnostics
-      action <- assertJust "Code action not found" . firstJust (caWithTitle "Remove stuffA, stuffC from import")
-        =<< getCodeActions docB (Range (Position 2 0) (Position 2 5))
+      [InR action@CodeAction { _title = actionTitle }, _]
+          <- getCodeActions docB (Range (Position 2 0) (Position 2 5))
+      liftIO $ "Remove stuffA, stuffC from import" @=? actionTitle
       executeCodeAction action
       contentAfterAction <- documentContents docB
       let expectedContentAfterAction = T.unlines
@@ -994,8 +995,9 @@ removeImportTests = testGroup "remove import actions"
             ]
       docB <- createDoc "ModuleB.hs" "haskell" contentB
       _ <- waitForDiagnostics
-      action <- assertJust "Code action not found" . firstJust (caWithTitle "Remove !!, <?> from import")
-        =<< getCodeActions docB (Range (Position 2 0) (Position 2 5))
+      [InR action@CodeAction { _title = actionTitle }, _]
+          <- getCodeActions docB (Range (Position 2 0) (Position 2 5))
+      liftIO $ "Remove !!, <?> from import" @=? actionTitle
       executeCodeAction action
       contentAfterAction <- documentContents docB
       let expectedContentAfterAction = T.unlines
@@ -1021,8 +1023,9 @@ removeImportTests = testGroup "remove import actions"
             ]
       docB <- createDoc "ModuleB.hs" "haskell" contentB
       _ <- waitForDiagnostics
-      action <- assertJust "Code action not found" . firstJust (caWithTitle "Remove A from import")
-        =<< getCodeActions docB (Range (Position 2 0) (Position 2 5))
+      [InR action@CodeAction { _title = actionTitle }, _]
+          <- getCodeActions docB (Range (Position 2 0) (Position 2 5))
+      liftIO $ "Remove A from import" @=? actionTitle
       executeCodeAction action
       contentAfterAction <- documentContents docB
       let expectedContentAfterAction = T.unlines
@@ -1047,8 +1050,9 @@ removeImportTests = testGroup "remove import actions"
             ]
       docB <- createDoc "ModuleB.hs" "haskell" contentB
       _ <- waitForDiagnostics
-      action <- assertJust "Code action not found" . firstJust (caWithTitle "Remove A, E, F from import")
-        =<< getCodeActions docB (Range (Position 2 0) (Position 2 5))
+      [InR action@CodeAction { _title = actionTitle }, _]
+          <- getCodeActions docB (Range (Position 2 0) (Position 2 5))
+      liftIO $ "Remove A, E, F from import" @=? actionTitle
       executeCodeAction action
       contentAfterAction <- documentContents docB
       let expectedContentAfterAction = T.unlines
@@ -1070,8 +1074,9 @@ removeImportTests = testGroup "remove import actions"
             ]
       docB <- createDoc "ModuleB.hs" "haskell" contentB
       _ <- waitForDiagnostics
-      action <- assertJust "Code action not found" . firstJust (caWithTitle "Remove import")
-        =<< getCodeActions docB (Range (Position 2 0) (Position 2 5))
+      [InR action@CodeAction { _title = actionTitle }, _]
+          <- getCodeActions docB (Range (Position 2 0) (Position 2 5))
+      liftIO $ "Remove import" @=? actionTitle
       executeCodeAction action
       contentAfterAction <- documentContents docB
       let expectedContentAfterAction = T.unlines
@@ -1094,8 +1099,9 @@ removeImportTests = testGroup "remove import actions"
             ]
       doc <- createDoc "ModuleC.hs" "haskell" content
       _ <- waitForDiagnostics
-      action <- assertJust "Code action not found" . firstJust (caWithTitle "Remove all redundant imports")
-        =<< getCodeActions doc (Range (Position 2 0) (Position 2 5))
+      [_, _, _, _, InR action@CodeAction { _title = actionTitle }]
+          <- getCodeActions doc (Range (Position 2 0) (Position 2 5))
+      liftIO $ "Remove all redundant imports" @=? actionTitle
       executeCodeAction action
       contentAfterAction <- documentContents doc
       let expectedContentAfterAction = T.unlines
@@ -1111,10 +1117,6 @@ removeImportTests = testGroup "remove import actions"
             ]
       liftIO $ expectedContentAfterAction @=? contentAfterAction
   ]
-  where
-    caWithTitle t = \case
-      InR  a@CodeAction{_title} -> guard (_title == t) >> Just a
-      _ -> Nothing
 
 extendImportTests :: TestTree
 extendImportTests = testGroup "extend import actions"
@@ -1784,57 +1786,6 @@ suggestHideShadowTests =
     , "(++) = id"
     ]
 
-disableWarningTests :: TestTree
-disableWarningTests =
-  testGroup "disable warnings" $
-    [
-      ( "missing-signatures"
-      , T.unlines
-          [ "{-# OPTIONS_GHC -Wall #-}"
-          , "main = putStrLn \"hello\""
-          ]
-      , T.unlines
-          [ "{-# OPTIONS_GHC -Wall #-}"
-          , "{-# OPTIONS_GHC -Wno-missing-signatures #-}"
-          , "main = putStrLn \"hello\""
-          ]
-      )
-    ,
-      ( "unused-imports"
-      , T.unlines
-          [ "{-# OPTIONS_GHC -Wall #-}"
-          , ""
-          , ""
-          , "module M where"
-          , ""
-          , "import Data.Functor"
-          ]
-      , T.unlines
-          [ "{-# OPTIONS_GHC -Wall #-}"
-          , "{-# OPTIONS_GHC -Wno-unused-imports #-}"
-          , ""
-          , ""
-          , "module M where"
-          , ""
-          , "import Data.Functor"
-          ]
-      )
-    ]
-      <&> \(warning, initialContent, expectedContent) -> testSession (T.unpack warning) $ do
-        doc <- createDoc "Module.hs" "haskell" initialContent
-        _ <- waitForDiagnostics
-        codeActs <- mapMaybe caResultToCodeAct <$> getCodeActions doc (Range (Position 0 0) (Position 0 0))
-        case find (\CodeAction{_title} -> _title == "Disable \"" <> warning <> "\" warnings") codeActs of
-          Nothing -> liftIO $ assertFailure "No code action with expected title"
-          Just action -> do
-            executeCodeAction action
-            contentAfterAction <- documentContents doc
-            liftIO $ expectedContent @=? contentAfterAction
- where
-  caResultToCodeAct = \case
-    InL _ -> Nothing
-    InR c -> Just c
-
 insertNewDefinitionTests :: TestTree
 insertNewDefinitionTests = testGroup "insert new definition actions"
   [ testSession "insert new function definition" $ do
@@ -2586,12 +2537,7 @@ removeRedundantConstraintsTests = let
     doc <- createDoc "Testing.hs" "haskell" code
     _ <- waitForDiagnostics
     actionsOrCommands <- getCodeActions doc (Range (Position 4 0) (Position 4 maxBound))
-    liftIO $ assertBool "Found some actions (other than \"disable warnings\")"
-      $ all isDisableWarningAction actionsOrCommands
-    where
-      isDisableWarningAction = \case
-        InR CodeAction{_title} -> "Disable" `T.isPrefixOf` _title && "warnings" `T.isSuffixOf` _title
-        _ -> False
+    liftIO $ assertBool "Found some actions" (null actionsOrCommands)
 
   in testGroup "remove redundant function constraints"
   [ check
@@ -4786,9 +4732,7 @@ asyncTests = testGroup "async"
             void waitForDiagnostics
             actions <- getCodeActions doc (Range (Position 1 0) (Position 1 0))
             liftIO $ [ _title | InR CodeAction{_title} <- actions] @=?
-              [ "add signature: foo :: a -> a"
-              , "Disable \"missing-signatures\" warnings"
-              ]
+              [ "add signature: foo :: a -> a" ]
     , testSession "request" $ do
             -- Execute a custom request that will block for 1000 seconds
             void $ sendRequest (SCustomMethod "test") $ toJSON $ BlockSeconds 1000
@@ -4800,9 +4744,7 @@ asyncTests = testGroup "async"
             void waitForDiagnostics
             actions <- getCodeActions doc (Range (Position 0 0) (Position 0 0))
             liftIO $ [ _title | InR CodeAction{_title} <- actions] @=?
-              [ "add signature: foo :: a -> a"
-              , "Disable \"missing-signatures\" warnings"
-              ]
+              [ "add signature: foo :: a -> a" ]
     ]
 
 
diff --git a/plugins/default/src/Ide/Plugin/Pragmas.hs b/plugins/default/src/Ide/Plugin/Pragmas.hs
index bef200645a..00dc3cbf9e 100644
--- a/plugins/default/src/Ide/Plugin/Pragmas.hs
+++ b/plugins/default/src/Ide/Plugin/Pragmas.hs
@@ -1,89 +1,102 @@
 {-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE NamedFieldPuns        #-}
 {-# LANGUAGE OverloadedStrings     #-}
 {-# LANGUAGE ViewPatterns          #-}
 
 -- | Provides code actions to add missing pragmas (whenever GHC suggests to)
-module Ide.Plugin.Pragmas
-  (
-      descriptor
-  ) where
-
-import           Control.Lens                    hiding (List)
-import qualified Data.HashMap.Strict             as H
-import           Data.Maybe                      (catMaybes)
-import qualified Data.Text                       as T
-import           Development.IDE                 as D
+module Ide.Plugin.Pragmas (descriptor) where
+
+import           Control.Applicative        ((<|>))
+import           Control.Lens               hiding (List)
+import           Control.Monad              (join)
+import           Control.Monad.IO.Class
+import qualified Data.HashMap.Strict        as H
+import           Data.List.Extra            (findIndex, nubOrdOn)
+import           Data.Maybe                 (catMaybes, fromMaybe, listToMaybe)
+import qualified Data.Text                  as T
+import           Development.IDE            as D
+import           Development.IDE.GHC.Compat
 import           Ide.Types
+import qualified Language.LSP.Server        as LSP
 import           Language.LSP.Types
-import qualified Language.LSP.Types      as J
-import qualified Language.LSP.Types.Lens as J
+import qualified Language.LSP.Types         as J
+import qualified Language.LSP.Types.Lens    as J
+import qualified Language.LSP.VFS           as VFS
+import qualified Text.Fuzzy                 as Fuzzy
 
-import           Control.Monad                   (join)
-import           Development.IDE.GHC.Compat
-import qualified Language.LSP.Server       as LSP
-import qualified Language.LSP.VFS as VFS
-import qualified Text.Fuzzy as Fuzzy
-import Data.List.Extra (nubOrd)
-import Control.Monad.IO.Class
+descriptor :: PluginId -> PluginDescriptor IdeState
+descriptor plId =
+  (defaultPluginDescriptor plId)
+    { pluginHandlers =
+        mkPluginHandler STextDocumentCodeAction codeActionProvider
+          <> mkPluginHandler STextDocumentCompletion completion
+    }
 
 -- ---------------------------------------------------------------------
 
-descriptor :: PluginId -> PluginDescriptor IdeState
-descriptor plId = (defaultPluginDescriptor plId)
-  { pluginHandlers = mkPluginHandler STextDocumentCodeAction codeActionProvider
-                  <> mkPluginHandler STextDocumentCompletion completion
-  }
+-- | Title and pragma
+type PragmaEdit = (T.Text, Pragma)
 
--- ---------------------------------------------------------------------
+data Pragma = LangExt T.Text | OptGHC T.Text
+  deriving (Show, Eq, Ord)
+
+codeActionProvider :: PluginMethodHandler IdeState TextDocumentCodeAction
+codeActionProvider state _plId (CodeActionParams _ _ docId _ (J.CodeActionContext (J.List diags) _monly)) = do
+  let mFile = docId ^. J.uri & uriToFilePath <&> toNormalizedFilePath'
+      uri = docId ^. J.uri
+  content <- fmap VFS.virtualFileText <$> LSP.getVirtualFile (toNormalizedUri uri)
+  pm <- liftIO $ fmap join $ runAction "Pragmas.GetParsedModule" state $ getParsedModule `traverse` mFile
+  let dflags = ms_hspp_opts . pm_mod_summary <$> pm
+      insertRange = maybe (Range (Position 0 0) (Position 0 0)) (`endOfModuleHeader` content) pm
+      pedits = nubOrdOn snd . concat $ suggest dflags <$> diags
+  return $ Right $ List $ pragmaEditToAction uri insertRange <$> pedits
 
 -- | Add a Pragma to the given URI at the top of the file.
--- Pragma is added to the first line of the Uri.
 -- It is assumed that the pragma name is a valid pragma,
 -- thus, not validated.
-mkPragmaEdit :: Uri -> T.Text -> WorkspaceEdit
-mkPragmaEdit uri pragmaName = res where
-    pos = J.Position 0 0
-    textEdits = J.List
-      [J.TextEdit (J.Range pos pos)
-                  ("{-# LANGUAGE " <> pragmaName <> " #-}\n")
-      ]
-    res = J.WorkspaceEdit
-      (Just $ H.singleton uri textEdits)
-      Nothing
+pragmaEditToAction :: Uri -> Range -> PragmaEdit -> (Command |? CodeAction)
+pragmaEditToAction uri range (title, p) =
+  InR $ J.CodeAction title (Just J.CodeActionQuickFix) (Just (J.List [])) Nothing Nothing (Just edit) Nothing
+  where
+    render (OptGHC x) = "{-# OPTIONS_GHC -Wno-" <> x <> " #-}\n"
+    render (LangExt x) = "{-# LANGUAGE " <> x <> " #-}\n"
+    textEdits = J.List [J.TextEdit range $ render p]
+    edit =
+      J.WorkspaceEdit
+        (Just $ H.singleton uri textEdits)
+        Nothing
+
+suggest :: Maybe DynFlags -> Diagnostic -> [PragmaEdit]
+suggest dflags diag =
+  suggestAddPragma dflags diag
+    ++ suggestDisableWarning diag
+
+-- ---------------------------------------------------------------------
+
+suggestDisableWarning :: Diagnostic -> [PragmaEdit]
+suggestDisableWarning Diagnostic {_code}
+  | Just (InR (T.stripPrefix "-W" -> Just w)) <- _code =
+    pure ("Disable \"" <> w <> "\" warnings", OptGHC w)
+  | otherwise = []
 
 -- ---------------------------------------------------------------------
+
 -- | Offer to add a missing Language Pragma to the top of a file.
 -- Pragmas are defined by a curated list of known pragmas, see 'possiblePragmas'.
-codeActionProvider :: PluginMethodHandler IdeState TextDocumentCodeAction
-codeActionProvider state _plId (CodeActionParams _ _ docId _ (J.CodeActionContext (J.List diags) _monly)) = liftIO $ do
-    let mFile = docId ^. J.uri & uriToFilePath <&> toNormalizedFilePath'
-    pm <- fmap join $ runAction "addPragma" state $ getParsedModule `traverse` mFile
-    let dflags = ms_hspp_opts . pm_mod_summary <$> pm
-        -- Get all potential Pragmas for all diagnostics.
-        pragmas = nubOrd $ concatMap (\d -> genPragma dflags (d ^. J.message)) diags
-    cmds <- mapM mkCodeAction pragmas
-    return $ Right $ List cmds
+suggestAddPragma :: Maybe DynFlags -> Diagnostic -> [PragmaEdit]
+suggestAddPragma mDynflags Diagnostic {_message} = genPragma _message
+  where
+    genPragma target =
+      [("Add \"" <> r <> "\"", LangExt r) | r <- findPragma target, r `notElem` disabled]
       where
-        mkCodeAction pragmaName = do
-          let
-            codeAction = InR $ J.CodeAction title (Just J.CodeActionQuickFix) (Just (J.List [])) Nothing Nothing (Just edit) Nothing
-            title = "Add \"" <> pragmaName <> "\""
-            edit = mkPragmaEdit (docId ^. J.uri) pragmaName
-          return codeAction
-
-        genPragma mDynflags target =
-            [ r | r <- findPragma target, r `notElem` disabled]
-          where
-            disabled
-              | Just dynFlags <- mDynflags
-                -- GHC does not export 'OnOff', so we have to view it as string
-              = catMaybes $ T.stripPrefix "Off " . T.pack . prettyPrint <$> extensions dynFlags
-              | otherwise
-                -- When the module failed to parse, we don't have access to its
-                -- dynFlags. In that case, simply don't disable any pragmas.
-              = []
-
--- ---------------------------------------------------------------------
+        disabled
+          | Just dynFlags <- mDynflags =
+            -- GHC does not export 'OnOff', so we have to view it as string
+            catMaybes $ T.stripPrefix "Off " . T.pack . prettyPrint <$> extensions dynFlags
+          | otherwise =
+            -- When the module failed to parse, we don't have access to its
+            -- dynFlags. In that case, simply don't disable any pragmas.
+            []
 
 -- | Find all Pragmas are an infix of the search term.
 findPragma :: T.Text -> [T.Text]
@@ -98,69 +111,86 @@ findPragma str = concatMap check possiblePragmas
     -- extension in an error message.
     possiblePragmas :: [T.Text]
     possiblePragmas =
-       [ name
-       | FlagSpec{flagSpecName = T.pack -> name} <- xFlags
-       , "Strict" /= name
-       ]
-
--- ---------------------------------------------------------------------
+      [ name
+        | FlagSpec {flagSpecName = T.pack -> name} <- xFlags,
+          "Strict" /= name
+      ]
 
 -- | All language pragmas, including the No- variants
 allPragmas :: [T.Text]
 allPragmas =
   concat
     [ [name, "No" <> name]
-    | FlagSpec{flagSpecName = T.pack -> name} <- xFlags
+      | FlagSpec {flagSpecName = T.pack -> name} <- xFlags
+    ]
+    <>
+    -- These pragmas are not part of xFlags as they are not reversable
+    -- by prepending "No".
+    [ -- Safe Haskell
+      "Unsafe",
+      "Trustworthy",
+      "Safe",
+      -- Language Version Extensions
+      "Haskell98",
+      "Haskell2010"
+      -- Maybe, GHC 2021 after its release?
     ]
-  <>
-  -- These pragmas are not part of xFlags as they are not reversable
-  -- by prepending "No".
-  [ -- Safe Haskell
-    "Unsafe"
-  , "Trustworthy"
-  , "Safe"
-
-    -- Language Version Extensions
-  , "Haskell98"
-  , "Haskell2010"
-    -- Maybe, GHC 2021 after its release?
-  ]
 
 -- ---------------------------------------------------------------------
 
 completion :: PluginMethodHandler IdeState TextDocumentCompletion
 completion _ide _ complParams = do
-    let (TextDocumentIdentifier uri) = complParams ^. J.textDocument
-        position = complParams ^. J.position
-    contents <- LSP.getVirtualFile $ toNormalizedUri uri
-    fmap (Right . InL) $ case (contents, uriToFilePath' uri) of
-        (Just cnts, Just _path) ->
-            result <$> VFS.getCompletionPrefix position cnts
-            where
-                result (Just pfix)
-                    | "{-# LANGUAGE" `T.isPrefixOf` VFS.fullLine pfix
-                    = List $ map buildCompletion
-                        (Fuzzy.simpleFilter (VFS.prefixText pfix) allPragmas)
-                    | otherwise
-                    = List []
-                result Nothing = List []
-                buildCompletion p =
-                    CompletionItem
-                      { _label = p,
-                        _kind = Just CiKeyword,
-                        _tags = Nothing,
-                        _detail = Nothing,
-                        _documentation = Nothing,
-                        _deprecated = Nothing,
-                        _preselect = Nothing,
-                        _sortText = Nothing,
-                        _filterText = Nothing,
-                        _insertText = Nothing,
-                        _insertTextFormat = Nothing,
-                        _textEdit = Nothing,
-                        _additionalTextEdits = Nothing,
-                        _commitCharacters = Nothing,
-                        _command = Nothing,
-                        _xdata = Nothing
-                      }
-        _ -> return $ List []
+  let (TextDocumentIdentifier uri) = complParams ^. J.textDocument
+      position = complParams ^. J.position
+  contents <- LSP.getVirtualFile $ toNormalizedUri uri
+  fmap (Right . InL) $ case (contents, uriToFilePath' uri) of
+    (Just cnts, Just _path) ->
+      result <$> VFS.getCompletionPrefix position cnts
+      where
+        result (Just pfix)
+          | "{-# LANGUAGE" `T.isPrefixOf` VFS.fullLine pfix =
+            List $
+              map
+                buildCompletion
+                (Fuzzy.simpleFilter (VFS.prefixText pfix) allPragmas)
+          | otherwise =
+            List []
+        result Nothing = List []
+        buildCompletion p =
+          CompletionItem
+            { _label = p,
+              _kind = Just CiKeyword,
+              _tags = Nothing,
+              _detail = Nothing,
+              _documentation = Nothing,
+              _deprecated = Nothing,
+              _preselect = Nothing,
+              _sortText = Nothing,
+              _filterText = Nothing,
+              _insertText = Nothing,
+              _insertTextFormat = Nothing,
+              _textEdit = Nothing,
+              _additionalTextEdits = Nothing,
+              _commitCharacters = Nothing,
+              _command = Nothing,
+              _xdata = Nothing
+            }
+    _ -> return $ List []
+
+-- ---------------------------------------------------------------------
+
+-- | Find the first non-blank line before the first of (module name / imports / declarations).
+-- Useful for inserting pragmas.
+endOfModuleHeader :: ParsedModule -> Maybe T.Text -> Range
+endOfModuleHeader pm contents =
+  let mod = unLoc $ pm_parsed_source pm
+      modNameLoc = getLoc <$> hsmodName mod
+      firstImportLoc = getLoc <$> listToMaybe (hsmodImports mod)
+      firstDeclLoc = getLoc <$> listToMaybe (hsmodDecls mod)
+      line =
+        fromMaybe 0 $
+          firstNonBlankBefore . _line . _start =<< srcSpanToRange
+            =<< modNameLoc <|> firstImportLoc <|> firstDeclLoc
+      firstNonBlankBefore n = (n -) . fromMaybe 0 . findIndex (not . T.null) . reverse . take n . T.lines <$> contents
+      loc = Position line 0
+   in Range loc loc
diff --git a/test/functional/Class.hs b/test/functional/Class.hs
index 0a0a2d0d4d..d8c925cdb6 100644
--- a/test/functional/Class.hs
+++ b/test/functional/Class.hs
@@ -34,7 +34,6 @@ tests = testGroup
           @?=
           [ Just "Add placeholders for '=='"
           , Just "Add placeholders for '/='"
-          , Just "Disable \"missing-methods\" warnings"
           ]
   , glodenTest "Creates a placeholder for '=='" "T1" "eq"
     $ \(eqAction:_) -> do
diff --git a/test/functional/FunctionalCodeAction.hs b/test/functional/FunctionalCodeAction.hs
index a150c274c6..573a6423a7 100644
--- a/test/functional/FunctionalCodeAction.hs
+++ b/test/functional/FunctionalCodeAction.hs
@@ -1,6 +1,8 @@
+{-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE CPP #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE NamedFieldPuns #-}
 
 module FunctionalCodeAction (tests) where
 
@@ -26,6 +28,7 @@ import           Test.Tasty
 import           Test.Tasty.ExpectedFailure (ignoreTestBecause, expectFailBecause)
 import           Test.Tasty.HUnit
 import           System.FilePath ((</>))
+import           System.IO.Extra (withTempDir)
 
 {-# ANN module ("HLint: ignore Reduce duplication"::String) #-}
 
@@ -34,6 +37,7 @@ tests = testGroup "code actions" [
       hlintTests
     , importTests
     , missingPragmaTests
+    , disableWarningTests
     , packageTests
     , redundantImportTests
     , renameTests
@@ -376,7 +380,7 @@ redundantImportTests = testGroup "redundant import code actions" [
     , testCase "doesn't touch other imports" $ runSession hlsCommand noLiteralCaps "test/testdata/redundantImportTest/" $ do
         doc <- openDoc "src/MultipleImports.hs" "haskell"
         _   <- waitForDiagnosticsFromSource doc "typecheck"
-        _ : InL cmd : _ <- getAllCodeActions doc
+        InL cmd : _ <- getAllCodeActions doc
         executeCommand cmd
         _ <- anyRequest
         contents <- documentContents doc
@@ -554,6 +558,57 @@ missingPragmaTests = testGroup "missing pragma warning code actions" [
             liftIO $ T.lines contents @?= expected
     ]
 
+disableWarningTests :: TestTree
+disableWarningTests =
+  testGroup "disable warnings" $
+    [
+      ( "missing-signatures"
+      , T.unlines
+          [ "{-# OPTIONS_GHC -Wall #-}"
+          , "main = putStrLn \"hello\""
+          ]
+      , T.unlines
+          [ "{-# OPTIONS_GHC -Wall #-}"
+          , "{-# OPTIONS_GHC -Wno-missing-signatures #-}"
+          , "main = putStrLn \"hello\""
+          ]
+      )
+    ,
+      ( "unused-imports"
+      , T.unlines
+          [ "{-# OPTIONS_GHC -Wall #-}"
+          , ""
+          , ""
+          , "module M where"
+          , ""
+          , "import Data.Functor"
+          ]
+      , T.unlines
+          [ "{-# OPTIONS_GHC -Wall #-}"
+          , "{-# OPTIONS_GHC -Wno-unused-imports #-}"
+          , ""
+          , ""
+          , "module M where"
+          , ""
+          , "import Data.Functor"
+          ]
+      )
+    ]
+      <&> \(warning, initialContent, expectedContent) -> testSession (T.unpack warning) $ do
+        doc <- createDoc "Module.hs" "haskell" initialContent
+        _ <- waitForDiagnostics
+        codeActs <- mapMaybe caResultToCodeAct <$> getCodeActions doc (Range (Position 0 0) (Position 0 0))
+        case find (\CodeAction{_title} -> _title == "Disable \"" <> warning <> "\" warnings") codeActs of
+          Nothing -> liftIO $ assertFailure "No code action with expected title"
+          Just action -> do
+            executeCodeAction action
+            contentAfterAction <- documentContents doc
+            liftIO $ expectedContent @=? contentAfterAction
+ where
+  caResultToCodeAct = \case
+    InL _ -> Nothing
+    InR c -> Just c
+
 unusedTermTests :: TestTree
 unusedTermTests = testGroup "unused term code actions" [
     ignoreTestBecause "no support for prefixing unused names with _" $ testCase "Prefixes with '_'" $
@@ -610,3 +665,7 @@ noLiteralCaps = def { C._textDocument = Just textDocumentCaps }
   where
     textDocumentCaps = def { C._codeAction = Just codeActionCaps }
     codeActionCaps = CodeActionClientCapabilities (Just True) Nothing Nothing
+
+testSession :: String -> Session () -> TestTree
+testSession name s = testCase name $ withTempDir $ \dir ->
+    runSession hlsCommand fullCaps dir s

From 7c771c6d69d9e2ec00949bdb110672916ef4df11 Mon Sep 17 00:00:00 2001
From: Potato Hatsue <1793913507@qq.com>
Date: Sun, 21 Feb 2021 13:24:07 +0800
Subject: [PATCH 2/9] Revert some format changes

---
 plugins/default/src/Ide/Plugin/Pragmas.hs | 126 +++++++++++-----------
 1 file changed, 62 insertions(+), 64 deletions(-)

diff --git a/plugins/default/src/Ide/Plugin/Pragmas.hs b/plugins/default/src/Ide/Plugin/Pragmas.hs
index 00dc3cbf9e..60219081e6 100644
--- a/plugins/default/src/Ide/Plugin/Pragmas.hs
+++ b/plugins/default/src/Ide/Plugin/Pragmas.hs
@@ -24,13 +24,13 @@ import qualified Language.LSP.Types.Lens    as J
 import qualified Language.LSP.VFS           as VFS
 import qualified Text.Fuzzy                 as Fuzzy
 
+-- ---------------------------------------------------------------------
+
 descriptor :: PluginId -> PluginDescriptor IdeState
-descriptor plId =
-  (defaultPluginDescriptor plId)
-    { pluginHandlers =
-        mkPluginHandler STextDocumentCodeAction codeActionProvider
-          <> mkPluginHandler STextDocumentCompletion completion
-    }
+descriptor plId = (defaultPluginDescriptor plId)
+  { pluginHandlers = mkPluginHandler STextDocumentCodeAction codeActionProvider
+                  <> mkPluginHandler STextDocumentCompletion completion
+  }
 
 -- ---------------------------------------------------------------------
 
@@ -88,15 +88,14 @@ suggestAddPragma mDynflags Diagnostic {_message} = genPragma _message
   where
     genPragma target =
       [("Add \"" <> r <> "\"", LangExt r) | r <- findPragma target, r `notElem` disabled]
-      where
-        disabled
-          | Just dynFlags <- mDynflags =
-            -- GHC does not export 'OnOff', so we have to view it as string
-            catMaybes $ T.stripPrefix "Off " . T.pack . prettyPrint <$> extensions dynFlags
-          | otherwise =
-            -- When the module failed to parse, we don't have access to its
-            -- dynFlags. In that case, simply don't disable any pragmas.
-            []
+    disabled
+      | Just dynFlags <- mDynflags =
+        -- GHC does not export 'OnOff', so we have to view it as string
+        catMaybes $ T.stripPrefix "Off " . T.pack . prettyPrint <$> extensions dynFlags
+      | otherwise =
+        -- When the module failed to parse, we don't have access to its
+        -- dynFlags. In that case, simply don't disable any pragmas.
+        []
 
 -- | Find all Pragmas are an infix of the search term.
 findPragma :: T.Text -> [T.Text]
@@ -121,61 +120,60 @@ allPragmas :: [T.Text]
 allPragmas =
   concat
     [ [name, "No" <> name]
-      | FlagSpec {flagSpecName = T.pack -> name} <- xFlags
-    ]
-    <>
-    -- These pragmas are not part of xFlags as they are not reversable
-    -- by prepending "No".
-    [ -- Safe Haskell
-      "Unsafe",
-      "Trustworthy",
-      "Safe",
-      -- Language Version Extensions
-      "Haskell98",
-      "Haskell2010"
-      -- Maybe, GHC 2021 after its release?
+    | FlagSpec{flagSpecName = T.pack -> name} <- xFlags
     ]
+  <>
+  -- These pragmas are not part of xFlags as they are not reversable
+  -- by prepending "No".
+  [ -- Safe Haskell
+    "Unsafe"
+  , "Trustworthy"
+  , "Safe"
+
+    -- Language Version Extensions
+  , "Haskell98"
+  , "Haskell2010"
+    -- Maybe, GHC 2021 after its release?
+  ]
 
 -- ---------------------------------------------------------------------
 
 completion :: PluginMethodHandler IdeState TextDocumentCompletion
 completion _ide _ complParams = do
-  let (TextDocumentIdentifier uri) = complParams ^. J.textDocument
-      position = complParams ^. J.position
-  contents <- LSP.getVirtualFile $ toNormalizedUri uri
-  fmap (Right . InL) $ case (contents, uriToFilePath' uri) of
-    (Just cnts, Just _path) ->
-      result <$> VFS.getCompletionPrefix position cnts
-      where
-        result (Just pfix)
-          | "{-# LANGUAGE" `T.isPrefixOf` VFS.fullLine pfix =
-            List $
-              map
-                buildCompletion
-                (Fuzzy.simpleFilter (VFS.prefixText pfix) allPragmas)
-          | otherwise =
-            List []
-        result Nothing = List []
-        buildCompletion p =
-          CompletionItem
-            { _label = p,
-              _kind = Just CiKeyword,
-              _tags = Nothing,
-              _detail = Nothing,
-              _documentation = Nothing,
-              _deprecated = Nothing,
-              _preselect = Nothing,
-              _sortText = Nothing,
-              _filterText = Nothing,
-              _insertText = Nothing,
-              _insertTextFormat = Nothing,
-              _textEdit = Nothing,
-              _additionalTextEdits = Nothing,
-              _commitCharacters = Nothing,
-              _command = Nothing,
-              _xdata = Nothing
-            }
-    _ -> return $ List []
+    let (TextDocumentIdentifier uri) = complParams ^. J.textDocument
+        position = complParams ^. J.position
+    contents <- LSP.getVirtualFile $ toNormalizedUri uri
+    fmap (Right . InL) $ case (contents, uriToFilePath' uri) of
+        (Just cnts, Just _path) ->
+            result <$> VFS.getCompletionPrefix position cnts
+            where
+                result (Just pfix)
+                    | "{-# LANGUAGE" `T.isPrefixOf` VFS.fullLine pfix
+                    = List $ map buildCompletion
+                        (Fuzzy.simpleFilter (VFS.prefixText pfix) allPragmas)
+                    | otherwise
+                    = List []
+                result Nothing = List []
+                buildCompletion p =
+                    CompletionItem
+                      { _label = p,
+                        _kind = Just CiKeyword,
+                        _tags = Nothing,
+                        _detail = Nothing,
+                        _documentation = Nothing,
+                        _deprecated = Nothing,
+                        _preselect = Nothing,
+                        _sortText = Nothing,
+                        _filterText = Nothing,
+                        _insertText = Nothing,
+                        _insertTextFormat = Nothing,
+                        _textEdit = Nothing,
+                        _additionalTextEdits = Nothing,
+                        _commitCharacters = Nothing,
+                        _command = Nothing,
+                        _xdata = Nothing
+                      }
+        _ -> return $ List []
 
 -- ---------------------------------------------------------------------
 

From 8c0ea29a39f9124a860c2c1c15eace798566ecbc Mon Sep 17 00:00:00 2001
From: Potato Hatsue <1793913507@qq.com>
Date: Sun, 21 Feb 2021 13:28:20 +0800
Subject: [PATCH 3/9] Revert some format changes

---
 plugins/default/src/Ide/Plugin/Pragmas.hs | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/plugins/default/src/Ide/Plugin/Pragmas.hs b/plugins/default/src/Ide/Plugin/Pragmas.hs
index 60219081e6..696f4c6d26 100644
--- a/plugins/default/src/Ide/Plugin/Pragmas.hs
+++ b/plugins/default/src/Ide/Plugin/Pragmas.hs
@@ -110,10 +110,10 @@ findPragma str = concatMap check possiblePragmas
     -- extension in an error message.
     possiblePragmas :: [T.Text]
     possiblePragmas =
-      [ name
-        | FlagSpec {flagSpecName = T.pack -> name} <- xFlags,
-          "Strict" /= name
-      ]
+       [ name
+       | FlagSpec{flagSpecName = T.pack -> name} <- xFlags
+       , "Strict" /= name
+       ]
 
 -- | All language pragmas, including the No- variants
 allPragmas :: [T.Text]

From 298be740a607556e856c3da7abb30ae802f84761 Mon Sep 17 00:00:00 2001
From: Potato Hatsue <1793913507@qq.com>
Date: Sun, 21 Feb 2021 13:40:18 +0800
Subject: [PATCH 4/9] Run pre-commit hook

---
 plugins/default/src/Ide/Plugin/Pragmas.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/plugins/default/src/Ide/Plugin/Pragmas.hs b/plugins/default/src/Ide/Plugin/Pragmas.hs
index 696f4c6d26..826fc1dfa0 100644
--- a/plugins/default/src/Ide/Plugin/Pragmas.hs
+++ b/plugins/default/src/Ide/Plugin/Pragmas.hs
@@ -58,7 +58,7 @@ pragmaEditToAction :: Uri -> Range -> PragmaEdit -> (Command |? CodeAction)
 pragmaEditToAction uri range (title, p) =
   InR $ J.CodeAction title (Just J.CodeActionQuickFix) (Just (J.List [])) Nothing Nothing (Just edit) Nothing
   where
-    render (OptGHC x) = "{-# OPTIONS_GHC -Wno-" <> x <> " #-}\n"
+    render (OptGHC x)  = "{-# OPTIONS_GHC -Wno-" <> x <> " #-}\n"
     render (LangExt x) = "{-# LANGUAGE " <> x <> " #-}\n"
     textEdits = J.List [J.TextEdit range $ render p]
     edit =

From 46fe2a0784ddce309bafef26c6c2a875172aaa81 Mon Sep 17 00:00:00 2001
From: Potato Hatsue <1793913507@qq.com>
Date: Sun, 21 Feb 2021 15:04:38 +0800
Subject: [PATCH 5/9] Fix and format class test

---
 test/functional/Class.hs | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/test/functional/Class.hs b/test/functional/Class.hs
index d8c925cdb6..4ab13b6511 100644
--- a/test/functional/Class.hs
+++ b/test/functional/Class.hs
@@ -1,26 +1,25 @@
-{-# LANGUAGE LambdaCase #-}
--- {-# LANGUAGE ViewPatterns #-}
+{-# LANGUAGE LambdaCase          #-}
 {-# LANGUAGE OverloadedStrings   #-}
 {-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE TypeOperators #-}
+{-# LANGUAGE TypeOperators       #-}
 module Class
   ( tests
   )
 where
 
+import           Control.Applicative.Combinators
 import           Control.Lens                    hiding ((<.>))
-import           Control.Monad.IO.Class          (MonadIO(liftIO))
+import           Control.Monad.IO.Class          (MonadIO (liftIO))
 import qualified Data.ByteString.Lazy            as BS
 import qualified Data.Text.Encoding              as T
 import           Language.LSP.Test
-import           Language.LSP.Types      hiding (_title, _command)
-import qualified Language.LSP.Types.Lens as J
+import           Language.LSP.Types              hiding (_command, _title)
+import qualified Language.LSP.Types.Lens         as J
 import           System.FilePath
 import           Test.Hls.Util
 import           Test.Tasty
 import           Test.Tasty.Golden
 import           Test.Tasty.HUnit
-import Control.Applicative.Combinators
 
 tests :: TestTree
 tests = testGroup
@@ -34,6 +33,7 @@ tests = testGroup
           @?=
           [ Just "Add placeholders for '=='"
           , Just "Add placeholders for '/='"
+          , Just "Disable \"missing-methods\" warnings"
           ]
   , glodenTest "Creates a placeholder for '=='" "T1" "eq"
     $ \(eqAction:_) -> do

From 4007428c3594c308a81c97338140aed2316cbacd Mon Sep 17 00:00:00 2001
From: Potato Hatsue <1793913507@qq.com>
Date: Sun, 21 Feb 2021 16:53:08 +0800
Subject: [PATCH 6/9] Fix and format func-test (code action)

---
 test/functional/FunctionalCodeAction.hs | 29 +++++++++++++------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/test/functional/FunctionalCodeAction.hs b/test/functional/FunctionalCodeAction.hs
index 573a6423a7..131c9d87af 100644
--- a/test/functional/FunctionalCodeAction.hs
+++ b/test/functional/FunctionalCodeAction.hs
@@ -1,34 +1,35 @@
-{-# LANGUAGE LambdaCase #-}
-{-# LANGUAGE CPP #-}
-{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE CPP                   #-}
 {-# LANGUAGE DuplicateRecordFields #-}
-{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE LambdaCase            #-}
+{-# LANGUAGE NamedFieldPuns        #-}
+{-# LANGUAGE OverloadedStrings     #-}
 
 module FunctionalCodeAction (tests) where
 
 import           Control.Applicative.Combinators
-import           Control.Lens hiding (List)
+import           Control.Lens                    hiding (List)
 import           Control.Monad
 import           Control.Monad.IO.Class
 import           Data.Aeson
 import           Data.Default
-import qualified Data.HashMap.Strict as HM
+import qualified Data.HashMap.Strict             as HM
 import           Data.List
 import           Data.Maybe
-import qualified Data.Text as T
+import qualified Data.Text                       as T
 import           Ide.Plugin.Config
-import           Language.LSP.Test as Test
+import           Language.LSP.Test               as Test
 import           Language.LSP.Types
-import qualified Language.LSP.Types.Lens as L
 import qualified Language.LSP.Types.Capabilities as C
+import qualified Language.LSP.Types.Lens         as L
 import           Test.Hls.Util
 import           Test.Hspec.Expectations
 
+import           System.FilePath                 ((</>))
+import           System.IO.Extra                 (withTempDir)
 import           Test.Tasty
-import           Test.Tasty.ExpectedFailure (ignoreTestBecause, expectFailBecause)
+import           Test.Tasty.ExpectedFailure      (expectFailBecause,
+                                                  ignoreTestBecause)
 import           Test.Tasty.HUnit
-import           System.FilePath ((</>))
-import           System.IO.Extra (withTempDir)
 
 {-# ANN module ("HLint: ignore Reduce duplication"::String) #-}
 
@@ -517,8 +518,8 @@ missingPragmaTests = testGroup "missing pragma warning code actions" [
             contents <- documentContents doc
 
             let expected =
-                    [ "{-# LANGUAGE TypeApplications #-}"
-                    , "{-# LANGUAGE ScopedTypeVariables #-}"
+                    [ "{-# LANGUAGE ScopedTypeVariables #-}"
+                    , "{-# LANGUAGE TypeApplications #-}"
                     , "module TypeApplications where"
                     , ""
                     , "foo :: forall a. a -> a"

From 7cdb788e0bd756b213324b67698e1332145902b6 Mon Sep 17 00:00:00 2001
From: Potato Hatsue <1793913507@qq.com>
Date: Sun, 21 Feb 2021 18:45:37 +0800
Subject: [PATCH 7/9] Update test

---
 test/functional/FunctionalCodeAction.hs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/functional/FunctionalCodeAction.hs b/test/functional/FunctionalCodeAction.hs
index 131c9d87af..468374b57f 100644
--- a/test/functional/FunctionalCodeAction.hs
+++ b/test/functional/FunctionalCodeAction.hs
@@ -518,8 +518,8 @@ missingPragmaTests = testGroup "missing pragma warning code actions" [
             contents <- documentContents doc
 
             let expected =
-                    [ "{-# LANGUAGE ScopedTypeVariables #-}"
-                    , "{-# LANGUAGE TypeApplications #-}"
+                    [ "{-# LANGUAGE TypeApplications #-}"
+                    , "{-# LANGUAGE ScopedTypeVariables #-}"
                     , "module TypeApplications where"
                     , ""
                     , "foo :: forall a. a -> a"

From 88f01d34187b417543bc43273709dd4c95277844 Mon Sep 17 00:00:00 2001
From: Potato Hatsue <1793913507@qq.com>
Date: Sun, 21 Feb 2021 21:53:45 +0800
Subject: [PATCH 8/9] Update test

---
 test/functional/FunctionalCodeAction.hs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/test/functional/FunctionalCodeAction.hs b/test/functional/FunctionalCodeAction.hs
index 468374b57f..4cda16326a 100644
--- a/test/functional/FunctionalCodeAction.hs
+++ b/test/functional/FunctionalCodeAction.hs
@@ -518,8 +518,14 @@ missingPragmaTests = testGroup "missing pragma warning code actions" [
             contents <- documentContents doc
 
             let expected =
+-- TODO: Why CPP???
+#if __GLASGOW_HASKELL__ < 810
+                    [ "{-# LANGUAGE ScopedTypeVariables #-}"
+                    , "{-# LANGUAGE TypeApplications #-}"
+#else
                     [ "{-# LANGUAGE TypeApplications #-}"
                     , "{-# LANGUAGE ScopedTypeVariables #-}"
+#endif
                     , "module TypeApplications where"
                     , ""
                     , "foo :: forall a. a -> a"

From eebf6b60ab0d934d77a7f24c225eb3f04fe21c7d Mon Sep 17 00:00:00 2001
From: Potato Hatsue <1793913507@qq.com>
Date: Mon, 22 Feb 2021 13:16:34 +0800
Subject: [PATCH 9/9] Don't look contents in endOfModuleHeader

---
 plugins/default/src/Ide/Plugin/Pragmas.hs | 17 ++++++-----------
 test/functional/FunctionalCodeAction.hs   |  2 +-
 2 files changed, 7 insertions(+), 12 deletions(-)

diff --git a/plugins/default/src/Ide/Plugin/Pragmas.hs b/plugins/default/src/Ide/Plugin/Pragmas.hs
index 826fc1dfa0..75c540d2d0 100644
--- a/plugins/default/src/Ide/Plugin/Pragmas.hs
+++ b/plugins/default/src/Ide/Plugin/Pragmas.hs
@@ -11,8 +11,8 @@ import           Control.Lens               hiding (List)
 import           Control.Monad              (join)
 import           Control.Monad.IO.Class
 import qualified Data.HashMap.Strict        as H
-import           Data.List.Extra            (findIndex, nubOrdOn)
-import           Data.Maybe                 (catMaybes, fromMaybe, listToMaybe)
+import           Data.List.Extra            (nubOrdOn)
+import           Data.Maybe                 (catMaybes, listToMaybe)
 import qualified Data.Text                  as T
 import           Development.IDE            as D
 import           Development.IDE.GHC.Compat
@@ -44,10 +44,9 @@ codeActionProvider :: PluginMethodHandler IdeState TextDocumentCodeAction
 codeActionProvider state _plId (CodeActionParams _ _ docId _ (J.CodeActionContext (J.List diags) _monly)) = do
   let mFile = docId ^. J.uri & uriToFilePath <&> toNormalizedFilePath'
       uri = docId ^. J.uri
-  content <- fmap VFS.virtualFileText <$> LSP.getVirtualFile (toNormalizedUri uri)
   pm <- liftIO $ fmap join $ runAction "Pragmas.GetParsedModule" state $ getParsedModule `traverse` mFile
   let dflags = ms_hspp_opts . pm_mod_summary <$> pm
-      insertRange = maybe (Range (Position 0 0) (Position 0 0)) (`endOfModuleHeader` content) pm
+      insertRange = maybe (Range (Position 0 0) (Position 0 0)) endOfModuleHeader pm
       pedits = nubOrdOn snd . concat $ suggest dflags <$> diags
   return $ Right $ List $ pragmaEditToAction uri insertRange <$> pedits
 
@@ -179,16 +178,12 @@ completion _ide _ complParams = do
 
 -- | Find the first non-blank line before the first of (module name / imports / declarations).
 -- Useful for inserting pragmas.
-endOfModuleHeader :: ParsedModule -> Maybe T.Text -> Range
-endOfModuleHeader pm contents =
+endOfModuleHeader :: ParsedModule -> Range
+endOfModuleHeader pm =
   let mod = unLoc $ pm_parsed_source pm
       modNameLoc = getLoc <$> hsmodName mod
       firstImportLoc = getLoc <$> listToMaybe (hsmodImports mod)
       firstDeclLoc = getLoc <$> listToMaybe (hsmodDecls mod)
-      line =
-        fromMaybe 0 $
-          firstNonBlankBefore . _line . _start =<< srcSpanToRange
-            =<< modNameLoc <|> firstImportLoc <|> firstDeclLoc
-      firstNonBlankBefore n = (n -) . fromMaybe 0 . findIndex (not . T.null) . reverse . take n . T.lines <$> contents
+      line = maybe 0 (_line . _start) (modNameLoc <|> firstImportLoc <|> firstDeclLoc >>= srcSpanToRange)
       loc = Position line 0
    in Range loc loc
diff --git a/test/functional/FunctionalCodeAction.hs b/test/functional/FunctionalCodeAction.hs
index 4cda16326a..116843390a 100644
--- a/test/functional/FunctionalCodeAction.hs
+++ b/test/functional/FunctionalCodeAction.hs
@@ -592,9 +592,9 @@ disableWarningTests =
           ]
       , T.unlines
           [ "{-# OPTIONS_GHC -Wall #-}"
-          , "{-# OPTIONS_GHC -Wno-unused-imports #-}"
           , ""
           , ""
+          , "{-# OPTIONS_GHC -Wno-unused-imports #-}"
           , "module M where"
           , ""
           , "import Data.Functor"