diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,62 @@
 ## Fourmolu 0.4.0.0
 
+* Fixed issue with leading commas in guards ([#123](https://github.com/fourmolu/fourmolu/pull/123))
+* Use trailing haddocks for record fields when using leading commas ([#124](https://github.com/fourmolu/fourmolu/pull/124))
+
+### Upstream changes:
+
+#### Ormolu 0.4.0.0
+
+* When a guard is located on its own line, the body associated with this
+  guard is indented by one extra level, so that it can easily be
+  distinguished from the guard predicate or pattern. [Issue
+  806](https://github.com/tweag/ormolu/issues/806).
+
+* Now a space is forced after `--` in line comments. [Issue
+  808](https://github.com/tweag/ormolu/issues/808).
+
+* Allow formatting Backpack signature files (`.hsig`). The switch between
+  regular module mode and signature mode is based on the file extension by
+  default, but can be overridden with the `-t / --source-type` command line
+  option. [Issue 600](https://github.com/tweag/ormolu/issues/600).
+
+* Blank Haddock comments are now eliminated. This also fixes issues with
+  differing ASTs in some special cases. [Issue
+  726](https://github.com/tweag/ormolu/issues/726).
+
+* Rewrite rules that are never active are now formatted correctly.
+  [Issue 823](https://github.com/tweag/ormolu/issues/823).
+
+* Promoted infix data constructors are now formatted correctly. [Issue 768](
+  https://github.com/tweag/ormolu/issues/768).
+
+* Switched to `ghc-lib-parser-9.2`.
+  [Issue 794](https://github.com/tweag/ormolu/issues/794).
+   * Support for the new syntax-related language extensions:
+     `OverloadedRecordDot` and `OverloadedRecordUpdate`
+     (disabled by default).
+     [Issue 709](https://github.com/tweag/ormolu/issues/709).
+   * Removed support for `record-dot-preprocessor`. For the getter syntax,
+     consider using `OverloadedRecordDot` instead. [Issue
+     659](https://github.com/tweag/ormolu/issues/659). [Issue
+     705](https://github.com/tweag/ormolu/issues/705).
+   * Support for the `GHC2021` language.
+
+#### Ormolu 0.3.1.0
+
+* Allow check mode when working with stdin input. [Issue 634](
+  https://github.com/tweag/ormolu/issues/634).
+
+* Now guards are printed on a new line if at least one guard is multiline or
+  if all guards together occupy more than one line. The body of each guard
+  is also indented one level deeper in that case. [Issue
+  712](https://github.com/tweag/ormolu/issues/712).
+
+* Invalid Haddock comments are no longer silently deleted, but rather converted
+  into regular comments. [Issue 474](https://github.com/tweag/ormolu/issues/474).
+
+## Fourmolu 0.4.0.0
+
 * Write "Loaded config from" message to `stderr` instead of `stdout` ([#42](https://github.com/fourmolu/fourmolu/pull/42))
 * Fixed issue with multiline haddocks in indented contexts ([#64](https://github.com/fourmolu/fourmolu/pull/64))
 * Avoid renaming magic comments ([#90](https://github.com/fourmolu/fourmolu/pull/90))
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -4,7 +4,8 @@
 [![Hackage](https://img.shields.io/hackage/v/fourmolu.svg?style=flat)](https://hackage.haskell.org/package/fourmolu)
 
 * [Configuration](#configuration)
-* [Building and installation](#building-and-installation)
+* [Installation](#installation)
+* [Building from source](#building-from-source)
 * [Usage](#usage)
     * [Editor integration](#editor-integration)
     * [Magic comments](#magic-comments)
@@ -50,16 +51,37 @@
 newlines-between-decls: 1 # number of newlines between top-level declarations
 ```
 
-See [here](fourmolu.yaml) for a config to simulate the behaviour of Ormolu.
+A config to simulate the behaviour of Ormolu ([as far as currently possible](https://github.com/fourmolu/fourmolu/issues/38)) would be:
 
+```yaml
+indentation: 2
+comma-style: trailing
+record-brace-space: true
+indent-wheres: true
+diff-friendly-import-export: false
+respectful: false
+haddock-style: single-line
+newlines-between-decls: 1
+```
+
 These options can also be set on the command line (which takes precedence over config files). Run `fourmolu -h` to see all options.
 
-## Building and installation
+## Installation
 
-Simply run `cabal v2-install fourmolu`, to install the latest release from Hackage.
+To install the latest release from Hackage, simply install with Cabal or Stack:
 
-You can also clone this repository, then build with Cabal or Stack.
+```console
+$ cabal install fourmolu
+$ stack install fourmolu
+```
 
+## Building from source
+
+```console
+$ cabal build
+$ stack build
+```
+
 ## Usage
 
 The following will print the formatted output to the standard output.
@@ -92,9 +114,17 @@
 $ fourmolu --mode check $(find . -name '*.hs')
 ```
 
+#### :zap: Beware git's `core.autocrlf` on Windows :zap:
+Fourmolu's output always uses LF line endings. In particular,
+`fourmolu --mode check` will fail if its input is correctly formatted
+*except* that it has CRLF line endings. This situation can happen on Windows
+when checking out a git repository without having set [`core.autocrlf`](
+https://www.git-scm.com/docs/git-config#Documentation/git-config.txt-coreautocrlf)
+to `false`.
+
 ### Editor integration
 
-Fourmolu can be integrated with your editor via the [Haskell Language Server](https://github.com/haskell/haskell-language-server).
+Fourmolu can be integrated with your editor via the [Haskell Language Server](https://haskell-language-server.readthedocs.io/en/latest/index.html). Just set `haskell.formattingProvider` to `fourmolu` ([instructions](https://haskell-language-server.readthedocs.io/en/latest/configuration.html#language-specific-server-options)).
 
 ### Magic comments
 
@@ -146,7 +176,7 @@
 8         | Cabal file parsing failed
 9         | Missing input file path when using stdin input and accounting for .cabal files
 100       | In checking mode: unformatted files
-101       | Inplace and check modes do not work with stdin
+101       | Inplace mode does not work with stdin
 102       | Other issue (with multiple input files)
 400       | Failed to load Fourmolu configuration file
 
@@ -166,7 +196,7 @@
 
 If there are any options you'd like to see, let us know. If it's not too complicated to implement (and especially if you implement it yourself!) then we'll probably add it.
 
-Run `cabal test` and `./format.sh` before submitting any pull requests.
+See `DEVELOPER.md` for documentation.
 
 ## License
 
diff --git a/app/Main.hs b/app/Main.hs
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -16,6 +16,7 @@
 import Data.Functor.Identity (Identity (..))
 import Data.List (intercalate, sort)
 import Data.Maybe (fromMaybe, mapMaybe)
+import qualified Data.Text as T
 import qualified Data.Text.IO as TIO
 import Data.Version (showVersion)
 import Development.GitRev
@@ -43,7 +44,12 @@
     [] -> mkConfigFromCWD opts
     ["-"] -> mkConfigFromCWD opts
     file : _ -> mkConfig file opts
-  let formatOne' = formatOne optCabalDefaultExtensions optMode cfg
+  let formatOne' =
+        formatOne
+          optCabalDefaultExtensions
+          optMode
+          optSourceType
+          cfg
 
   exitCode <- case optInputFiles of
     [] -> formatOne' Nothing
@@ -71,62 +77,86 @@
   CabalDefaultExtensionsOpts ->
   -- | Mode of operation
   Mode ->
+  -- | The 'SourceType' requested by the user
+  Maybe SourceType ->
   -- | Configuration
   Config RegionIndices ->
   -- | File to format or stdin as 'Nothing'
   Maybe FilePath ->
   IO ExitCode
-formatOne CabalDefaultExtensionsOpts {..} mode config mpath =
-  withPrettyOrmoluExceptions (cfgColorMode config) $
+formatOne CabalDefaultExtensionsOpts {..} mode reqSourceType rawConfig mpath =
+  withPrettyOrmoluExceptions (cfgColorMode rawConfig) $ do
     case FP.normalise <$> mpath of
+      -- input source = STDIN
       Nothing -> do
-        extraDynOptions <-
-          if optUseCabalDefaultExtensions
-            then case optStdinInputFile of
-              Just stdinInputFile ->
-                getCabalExtensionDynOptions stdinInputFile
-              Nothing -> throwIO OrmoluMissingStdinInputFile
-            else pure []
-        r <- ormoluStdin (configPlus extraDynOptions)
+        resultConfig <-
+          patchConfig Nothing
+            <$> if optUseCabalDefaultExtensions
+              then case optStdinInputFile of
+                Just stdinInputFile ->
+                  getCabalExtensionDynOptions stdinInputFile
+                Nothing -> throwIO OrmoluMissingStdinInputFile
+              else pure []
         case mode of
           Stdout -> do
-            TIO.putStr r
+            ormoluStdin resultConfig >>= TIO.putStr
             return ExitSuccess
-          _ -> do
+          InPlace -> do
             hPutStrLn
               stderr
-              "This feature is not supported when input comes from stdin."
+              "In place editing is not supported when input comes from stdin."
             -- 101 is different from all the other exit codes we already use.
             return (ExitFailure 101)
+          Check -> do
+            -- ormoluStdin is not used because we need the originalInput
+            originalInput <- getContentsUtf8
+            let stdinRepr = "<stdin>"
+            formattedInput <-
+              ormolu resultConfig stdinRepr (T.unpack originalInput)
+            handleDiff originalInput formattedInput stdinRepr
+      -- input source = a file
       Just inputFile -> do
-        extraDynOptions <-
-          if optUseCabalDefaultExtensions
-            then getCabalExtensionDynOptions inputFile
-            else pure []
-        originalInput <- readFileUtf8 inputFile
-        formattedInput <- ormoluFile (configPlus extraDynOptions) inputFile
+        resultConfig <-
+          patchConfig (Just (detectSourceType inputFile))
+            <$> if optUseCabalDefaultExtensions
+              then getCabalExtensionDynOptions inputFile
+              else pure []
         case mode of
           Stdout -> do
-            TIO.putStr formattedInput
+            ormoluFile resultConfig inputFile >>= TIO.putStr
             return ExitSuccess
           InPlace -> do
-            -- Only write when the contents have changed, in order to avoid
-            -- updating the modified timestamp if the file was already correctly
-            -- formatted.
+            -- ormoluFile is not used because we need originalInput
+            originalInput <- readFileUtf8 inputFile
+            formattedInput <-
+              ormolu resultConfig inputFile (T.unpack originalInput)
             when (formattedInput /= originalInput) $
               writeFileUtf8 inputFile formattedInput
             return ExitSuccess
-          Check ->
-            case diffText originalInput formattedInput inputFile of
-              Nothing -> return ExitSuccess
-              Just diff -> do
-                runTerm (printTextDiff diff) (cfgColorMode config) stderr
-                -- 100 is different to all the other exit code that are emitted
-                -- either from an 'OrmoluException' or from 'error' and
-                -- 'notImplemented'.
-                return (ExitFailure 100)
+          Check -> do
+            -- ormoluFile is not used because we need originalInput
+            originalInput <- readFileUtf8 inputFile
+            formattedInput <-
+              ormolu resultConfig inputFile (T.unpack originalInput)
+            handleDiff originalInput formattedInput inputFile
   where
-    configPlus dynOpts = config {cfgDynOptions = cfgDynOptions config ++ dynOpts}
+    patchConfig mdetectedSourceType dynOpts =
+      rawConfig
+        { cfgDynOptions = cfgDynOptions rawConfig ++ dynOpts,
+          cfgSourceType =
+            fromMaybe
+              ModuleSource
+              (reqSourceType <|> mdetectedSourceType)
+        }
+    handleDiff originalInput formattedInput fileRepr =
+      case diffText originalInput formattedInput fileRepr of
+        Nothing -> return ExitSuccess
+        Just diff -> do
+          runTerm (printTextDiff diff) (cfgColorMode rawConfig) stderr
+          -- 100 is different to all the other exit code that are emitted
+          -- either from an 'OrmoluException' or from 'error' and
+          -- 'notImplemented'.
+          return (ExitFailure 100)
 
 ----------------------------------------------------------------------------
 -- Command line options parsing
@@ -138,6 +168,8 @@
     optConfig :: !(Config RegionIndices),
     -- | Options for respecting default-extensions from .cabal files
     optCabalDefaultExtensions :: CabalDefaultExtensionsOpts,
+    -- | Source type option, where 'Nothing' means autodetection
+    optSourceType :: !(Maybe SourceType),
     -- | Fourmolu-specific options
     optPrinterOpts :: !PrinterOptsPartial,
     -- | Haskell source files to format or stdin (when the list is empty)
@@ -214,6 +246,7 @@
         )
     <*> configParser
     <*> cabalDefaultExtensionsParser
+    <*> sourceTypeParser
     <*> printerOptsParser
     <*> (many . strArgument . mconcat)
       [ metavar "FILE",
@@ -257,6 +290,10 @@
         short 'c',
         help "Fail if formatting is not idempotent"
       ]
+    -- We cannot parse the source type here, because we might need to do
+    -- autodection based on the input file extension (not available here)
+    -- before storing the resolved value in the config struct.
+    <*> pure ModuleSource
     <*> (option parseBoundedEnum . mconcat)
       [ long "color",
         metavar "WHEN",
@@ -349,6 +386,16 @@
       ]
   pure PrinterOpts {..}
 
+sourceTypeParser :: Parser (Maybe SourceType)
+sourceTypeParser =
+  (option parseSourceType . mconcat)
+    [ long "source-type",
+      short 't',
+      metavar "TYPE",
+      value Nothing,
+      help "Set the type of source; TYPE can be 'module', 'sig', or 'auto' (the default)"
+    ]
+
 ----------------------------------------------------------------------------
 -- Helpers
 
@@ -469,3 +516,12 @@
 mkConfigFromCWD opts = do
   cwd <- getCurrentDirectory
   mkConfig cwd opts
+
+-- | Parse the 'SourceType'. 'Nothing' means that autodetection based on
+-- file extension is requested.
+parseSourceType :: ReadM (Maybe SourceType)
+parseSourceType = eitherReader $ \case
+  "module" -> Right (Just ModuleSource)
+  "sig" -> Right (Just SignatureSource)
+  "auto" -> Right Nothing
+  s -> Left $ "unknown source type: " ++ s
diff --git a/data/examples/declaration/data/field-layout/record-four-out.hs b/data/examples/declaration/data/field-layout/record-four-out.hs
--- a/data/examples/declaration/data/field-layout/record-four-out.hs
+++ b/data/examples/declaration/data/field-layout/record-four-out.hs
@@ -2,11 +2,11 @@
 
 -- | Foo.
 data Foo = Foo
-    { -- | Something
-      foo :: Foo Int Int
-    , -- | Something else
-      bar ::
+    { foo :: Foo Int Int
+    -- ^ Something
+    , bar ::
         Bar
             Char
             Char
+    -- ^ Something else
     }
diff --git a/data/examples/declaration/data/record-four-out.hs b/data/examples/declaration/data/record-four-out.hs
--- a/data/examples/declaration/data/record-four-out.hs
+++ b/data/examples/declaration/data/record-four-out.hs
@@ -2,22 +2,22 @@
 
 -- | Something.
 data Foo = Foo
-    { -- | X
-      fooX :: Int
-    , -- | Y
-      fooY :: Int
-    , -- | BarBaz
-      fooBar, fooBaz :: NonEmpty (Identity Bool)
-    , -- | GagGog
-      fooGag
+    { fooX :: Int
+    -- ^ X
+    , fooY :: Int
+    -- ^ Y
+    , fooBar, fooBaz :: NonEmpty (Identity Bool)
+    -- ^ BarBaz
+    , fooGag
       , fooGog ::
         NonEmpty
             ( Indentity
                 Bool
             )
-    , -- | Huh!
-      fooFoo
+    -- ^ GagGog
+    , fooFoo
       , barBar ::
         Int
+    -- ^ Huh!
     }
     deriving (Eq, Show)
diff --git a/data/examples/declaration/data/record-multi-const-four-out.hs b/data/examples/declaration/data/record-multi-const-four-out.hs
--- a/data/examples/declaration/data/record-multi-const-four-out.hs
+++ b/data/examples/declaration/data/record-multi-const-four-out.hs
@@ -3,15 +3,15 @@
 -- | Something.
 data Foo
     = Foo
-        { -- | X
-          fooX :: Int
-        , -- | Y
-          fooY :: Int
+        { fooX :: Int
+        -- ^ X
+        , fooY :: Int
+        -- ^ Y
         }
     | Bar
-        { -- | X
-          barX :: Int
-        , -- | Y
-          barY :: Int
+        { barX :: Int
+        -- ^ X
+        , barY :: Int
+        -- ^ Y
         }
     deriving (Eq, Show)
diff --git a/data/examples/declaration/rewrite-rule/never-active-four-out.hs b/data/examples/declaration/rewrite-rule/never-active-four-out.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/declaration/rewrite-rule/never-active-four-out.hs
@@ -0,0 +1,1 @@
+{-# RULES "map-loop" [~] forall f. map' f = map' (id . f) #-}
diff --git a/data/examples/declaration/rewrite-rule/never-active-out.hs b/data/examples/declaration/rewrite-rule/never-active-out.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/declaration/rewrite-rule/never-active-out.hs
@@ -0,0 +1,1 @@
+{-# RULES "map-loop" [~] forall f. map' f = map' (id . f) #-}
diff --git a/data/examples/declaration/rewrite-rule/never-active.hs b/data/examples/declaration/rewrite-rule/never-active.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/declaration/rewrite-rule/never-active.hs
@@ -0,0 +1,1 @@
+{-# RULES "map-loop" [ ~  ]  forall f . map' f = map' (id . f) #-}
diff --git a/data/examples/declaration/type-families/closed-type-family/injective-four-out.hs b/data/examples/declaration/type-families/closed-type-family/injective-four-out.hs
--- a/data/examples/declaration/type-families/closed-type-family/injective-four-out.hs
+++ b/data/examples/declaration/type-families/closed-type-family/injective-four-out.hs
@@ -1,5 +1,4 @@
 type family Id a = result | result -> a where
     Id a = a
-
 type family G (a :: k) b c = foo | foo -> k b where
     G a b c = (a, b)
diff --git a/data/examples/declaration/type-families/closed-type-family/multi-line-four-out.hs b/data/examples/declaration/type-families/closed-type-family/multi-line-four-out.hs
--- a/data/examples/declaration/type-families/closed-type-family/multi-line-four-out.hs
+++ b/data/examples/declaration/type-families/closed-type-family/multi-line-four-out.hs
@@ -4,7 +4,6 @@
     where
     Id a =
         a
-
 type family
     G
         (a :: k)
@@ -14,7 +13,6 @@
     where
     G a b c =
         (a, b)
-
 type family
     F a ::
         * -> *
diff --git a/data/examples/declaration/type/promotion-1-four-out.hs b/data/examples/declaration/type/promotion-1-four-out.hs
--- a/data/examples/declaration/type/promotion-1-four-out.hs
+++ b/data/examples/declaration/type/promotion-1-four-out.hs
@@ -7,3 +7,5 @@
 
 type E = TypeError ( 'Text "Some text")
 type G = '[ '( 'Just, 'Bool)]
+
+type X = () '`PromotedInfix` ()
diff --git a/data/examples/declaration/type/promotion-1-out.hs b/data/examples/declaration/type/promotion-1-out.hs
--- a/data/examples/declaration/type/promotion-1-out.hs
+++ b/data/examples/declaration/type/promotion-1-out.hs
@@ -13,3 +13,5 @@
 type E = TypeError ( 'Text "Some text")
 
 type G = '[ '( 'Just, 'Bool)]
+
+type X = () '`PromotedInfix` ()
diff --git a/data/examples/declaration/type/promotion-1.hs b/data/examples/declaration/type/promotion-1.hs
--- a/data/examples/declaration/type/promotion-1.hs
+++ b/data/examples/declaration/type/promotion-1.hs
@@ -7,3 +7,5 @@
 
 type E = TypeError ('Text "Some text")
 type G = '[ '( 'Just, 'Bool) ]
+
+type X = () '`PromotedInfix` ()
diff --git a/data/examples/declaration/value/function/arrow/proc-do-complex-four-out.hs b/data/examples/declaration/value/function/arrow/proc-do-complex-four-out.hs
--- a/data/examples/declaration/value/function/arrow/proc-do-complex-four-out.hs
+++ b/data/examples/declaration/value/function/arrow/proc-do-complex-four-out.hs
@@ -29,7 +29,8 @@
                     Left
                         ( z
                             , w
-                            ) -> \u -> -- Procs can have lambdas
+                            ) -> \u ->
+                            -- Procs can have lambdas
                             let v =
                                     u -- Actually never used
                                         ^ 2
diff --git a/data/examples/declaration/value/function/arrow/proc-do-complex-out.hs b/data/examples/declaration/value/function/arrow/proc-do-complex-out.hs
--- a/data/examples/declaration/value/function/arrow/proc-do-complex-out.hs
+++ b/data/examples/declaration/value/function/arrow/proc-do-complex-out.hs
@@ -29,7 +29,8 @@
           Left
             ( z,
               w
-              ) -> \u -> -- Procs can have lambdas
+              ) -> \u ->
+              -- Procs can have lambdas
               let v =
                     u -- Actually never used
                       ^ 2
diff --git a/data/examples/declaration/value/function/arrow/proc-lambdas-four-out.hs b/data/examples/declaration/value/function/arrow/proc-lambdas-four-out.hs
--- a/data/examples/declaration/value/function/arrow/proc-lambdas-four-out.hs
+++ b/data/examples/declaration/value/function/arrow/proc-lambdas-four-out.hs
@@ -5,5 +5,6 @@
 bar =
     proc x -> \f g h ->
         \() ->
-            \(Left (x, y)) -> -- Tuple value
+            \(Left (x, y)) ->
+                -- Tuple value
                 f (g (h x)) -< y
diff --git a/data/examples/declaration/value/function/arrow/proc-lambdas-out.hs b/data/examples/declaration/value/function/arrow/proc-lambdas-out.hs
--- a/data/examples/declaration/value/function/arrow/proc-lambdas-out.hs
+++ b/data/examples/declaration/value/function/arrow/proc-lambdas-out.hs
@@ -5,5 +5,6 @@
 bar =
   proc x -> \f g h ->
     \() ->
-      \(Left (x, y)) -> -- Tuple value
+      \(Left (x, y)) ->
+        -- Tuple value
         f (g (h x)) -< y
diff --git a/data/examples/declaration/value/function/case-multi-line-guards-out.hs b/data/examples/declaration/value/function/case-multi-line-guards-out.hs
--- a/data/examples/declaration/value/function/case-multi-line-guards-out.hs
+++ b/data/examples/declaration/value/function/case-multi-line-guards-out.hs
@@ -3,8 +3,8 @@
   case x of
     x
       | x > 10 ->
-        foo
-          + bar
+          foo
+            + bar
     x | x > 5 -> 10
     _ -> 20
 
diff --git a/data/examples/declaration/value/function/multi-way-if-out.hs b/data/examples/declaration/value/function/multi-way-if-out.hs
--- a/data/examples/declaration/value/function/multi-way-if-out.hs
+++ b/data/examples/declaration/value/function/multi-way-if-out.hs
@@ -6,7 +6,7 @@
   if
       | x > y -> x
       | x < y ->
-        y
+          y
       | otherwise -> x
 
 baz =
diff --git a/data/examples/declaration/value/function/multiple-guards-out.hs b/data/examples/declaration/value/function/multiple-guards-out.hs
--- a/data/examples/declaration/value/function/multiple-guards-out.hs
+++ b/data/examples/declaration/value/function/multiple-guards-out.hs
@@ -6,9 +6,9 @@
 bar :: Int -> Int
 bar x
   | x == 5 =
-    foo x
-      + foo 10
+      foo x
+        + foo 10
   | x == 6 =
-    foo x
-      + foo 20
+      foo x
+        + foo 20
   | otherwise = foo 100
diff --git a/data/examples/declaration/value/function/multiple-guards.hs b/data/examples/declaration/value/function/multiple-guards.hs
--- a/data/examples/declaration/value/function/multiple-guards.hs
+++ b/data/examples/declaration/value/function/multiple-guards.hs
@@ -1,7 +1,6 @@
 foo :: Int -> Int
-foo x
-  | x == 5 = 10
-  | otherwise = 12
+foo x | x == 5 = 10
+      | otherwise = 12
 
 bar :: Int -> Int
 bar x
diff --git a/data/examples/declaration/value/function/operators-2-out.hs b/data/examples/declaration/value/function/operators-2-out.hs
--- a/data/examples/declaration/value/function/operators-2-out.hs
+++ b/data/examples/declaration/value/function/operators-2-out.hs
@@ -1,4 +1,4 @@
 foo n
   | x || y && z || n ** x
       || x && n =
-    42
+      42
diff --git a/data/examples/declaration/value/function/pattern/many-guards-in-singleline-four-out.hs b/data/examples/declaration/value/function/pattern/many-guards-in-singleline-four-out.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/declaration/value/function/pattern/many-guards-in-singleline-four-out.hs
@@ -0,0 +1,3 @@
+foobar x | x <- 5 = 5 | x <- 6 = 6 | otherwise = 7
+
+foobaz | x <- 5 = 5 | x <- 6 = 6 | otherwise = 7
diff --git a/data/examples/declaration/value/function/pattern/many-guards-in-singleline-out.hs b/data/examples/declaration/value/function/pattern/many-guards-in-singleline-out.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/declaration/value/function/pattern/many-guards-in-singleline-out.hs
@@ -0,0 +1,3 @@
+foobar x | x <- 5 = 5 | x <- 6 = 6 | otherwise = 7
+
+foobaz | x <- 5 = 5 | x <- 6 = 6 | otherwise = 7
diff --git a/data/examples/declaration/value/function/pattern/many-guards-in-singleline.hs b/data/examples/declaration/value/function/pattern/many-guards-in-singleline.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/declaration/value/function/pattern/many-guards-in-singleline.hs
@@ -0,0 +1,3 @@
+foobar x | x <- 5 = 5 | x <- 6 = 6 | otherwise = 7
+
+foobaz | x <- 5 = 5 | x <- 6 = 6 | otherwise = 7
diff --git a/data/examples/declaration/value/function/pattern/multiline-guard-statement-four-out.hs b/data/examples/declaration/value/function/pattern/multiline-guard-statement-four-out.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/declaration/value/function/pattern/multiline-guard-statement-four-out.hs
@@ -0,0 +1,6 @@
+foobarbar :: Int -> Bool
+foobarbar
+    | x <-
+        5 = case x of
+        5 -> True
+        _ -> False
diff --git a/data/examples/declaration/value/function/pattern/multiline-guard-statement-out.hs b/data/examples/declaration/value/function/pattern/multiline-guard-statement-out.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/declaration/value/function/pattern/multiline-guard-statement-out.hs
@@ -0,0 +1,6 @@
+foobarbar :: Int -> Bool
+foobarbar
+  | x <-
+      5 = case x of
+      5 -> True
+      _ -> False
diff --git a/data/examples/declaration/value/function/pattern/multiline-guard-statement.hs b/data/examples/declaration/value/function/pattern/multiline-guard-statement.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/declaration/value/function/pattern/multiline-guard-statement.hs
@@ -0,0 +1,5 @@
+foobarbar :: Int -> Bool
+foobarbar | x <-
+    5 = case x of
+  5 -> True
+  _ -> False
diff --git a/data/examples/declaration/value/function/pattern/multiple-guard-statements-four-out.hs b/data/examples/declaration/value/function/pattern/multiple-guard-statements-four-out.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/declaration/value/function/pattern/multiple-guard-statements-four-out.hs
@@ -0,0 +1,6 @@
+foobarbar :: Int -> Bool
+foobarbar
+    | x <- 5
+    , y <- 6 = case x of
+        5 -> True
+        _ -> False
diff --git a/data/examples/declaration/value/function/pattern/multiple-guard-statements-out.hs b/data/examples/declaration/value/function/pattern/multiple-guard-statements-out.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/declaration/value/function/pattern/multiple-guard-statements-out.hs
@@ -0,0 +1,6 @@
+foobarbar :: Int -> Bool
+foobarbar
+  | x <- 5,
+    y <- 6 = case x of
+      5 -> True
+      _ -> False
diff --git a/data/examples/declaration/value/function/pattern/multiple-guard-statements.hs b/data/examples/declaration/value/function/pattern/multiple-guard-statements.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/declaration/value/function/pattern/multiple-guard-statements.hs
@@ -0,0 +1,4 @@
+foobarbar :: Int -> Bool
+foobarbar | x <- 5, y <- 6 = case x of
+  5 -> True
+  _ -> False
diff --git a/data/examples/declaration/value/function/record/dot-multiline-four-out.hs b/data/examples/declaration/value/function/record/dot-multiline-four-out.hs
deleted file mode 100644
--- a/data/examples/declaration/value/function/record/dot-multiline-four-out.hs
+++ /dev/null
@@ -1,15 +0,0 @@
-{-# OPTIONS_GHC -fplugin=RecordDotPreprocessor #-}
-
-bar' =
-    (Foo 1){bar = 2
-           }
-
-fooplus'''' f n =
-    f{foo = n
-      , bar = n
-     }
-
-fooplus''''' f n =
-    f
-        { foo = n
-        }
diff --git a/data/examples/declaration/value/function/record/dot-multiline-out.hs b/data/examples/declaration/value/function/record/dot-multiline-out.hs
deleted file mode 100644
--- a/data/examples/declaration/value/function/record/dot-multiline-out.hs
+++ /dev/null
@@ -1,15 +0,0 @@
-{-# OPTIONS_GHC -fplugin=RecordDotPreprocessor #-}
-
-bar' =
-  (Foo 1){bar = 2
-         }
-
-fooplus'''' f n =
-  f{foo = n,
-    bar = n
-   }
-
-fooplus''''' f n =
-  f
-    { foo = n
-    }
diff --git a/data/examples/declaration/value/function/record/dot-multiline.hs b/data/examples/declaration/value/function/record/dot-multiline.hs
deleted file mode 100644
--- a/data/examples/declaration/value/function/record/dot-multiline.hs
+++ /dev/null
@@ -1,10 +0,0 @@
-{-# OPTIONS_GHC -fplugin=RecordDotPreprocessor #-}
-bar' = (Foo 1){bar = 2
-              }
-
-fooplus'''' f n = f{foo = n,
-                    bar = n
-                   }
-
-fooplus''''' f n = f
-                   { foo = n }
diff --git a/data/examples/declaration/value/function/record/dot-singleline-four-out.hs b/data/examples/declaration/value/function/record/dot-singleline-four-out.hs
deleted file mode 100644
--- a/data/examples/declaration/value/function/record/dot-singleline-four-out.hs
+++ /dev/null
@@ -1,15 +0,0 @@
-{-# OPTIONS_GHC -fplugin=RecordDotPreprocessor #-}
-
-data Foo = Foo {bar :: Int}
-
-mfoo = fmap (.bar) $ Nothing
-
-bar = (Foo 1).bar
-
-fooplus f n = f{foo = f.bar + n}
-
-fooplus' f n = f{foo = f.bar + n}
-
-fooplus'' f n = f{foo = f.bar + n}
-
-fooplus''' f n = f{foo = f.bar + n}
diff --git a/data/examples/declaration/value/function/record/dot-singleline-out.hs b/data/examples/declaration/value/function/record/dot-singleline-out.hs
deleted file mode 100644
--- a/data/examples/declaration/value/function/record/dot-singleline-out.hs
+++ /dev/null
@@ -1,15 +0,0 @@
-{-# OPTIONS_GHC -fplugin=RecordDotPreprocessor #-}
-
-data Foo = Foo {bar :: Int}
-
-mfoo = fmap (.bar) $ Nothing
-
-bar = (Foo 1).bar
-
-fooplus f n = f{foo = f.bar + n}
-
-fooplus' f n = f {foo = f.bar + n}
-
-fooplus'' f n = f {foo = f.bar + n}
-
-fooplus''' f n = f {foo = f.bar + n}
diff --git a/data/examples/declaration/value/function/record/dot-singleline.hs b/data/examples/declaration/value/function/record/dot-singleline.hs
deleted file mode 100644
--- a/data/examples/declaration/value/function/record/dot-singleline.hs
+++ /dev/null
@@ -1,14 +0,0 @@
-{-# OPTIONS_GHC -fplugin=RecordDotPreprocessor #-}
-data Foo = Foo { bar :: Int }
-
-mfoo = fmap (.bar)   $ Nothing
-
-bar = (  Foo 1).bar
-
-fooplus f n = f{foo = f.bar + n}
-
-fooplus' f n = f { foo = f.bar + n}
-
-fooplus'' f n = f {foo = f.bar + n}
-
-fooplus''' f n = f{ foo = f.bar + n}
diff --git a/data/examples/declaration/value/function/record/record-dot-four-out.hs b/data/examples/declaration/value/function/record/record-dot-four-out.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/declaration/value/function/record/record-dot-four-out.hs
@@ -0,0 +1,16 @@
+{-# LANGUAGE OverloadedRecordDot #-}
+{-# LANGUAGE OverloadedRecordUpdate #-}
+
+data Foo = Foo {bar :: Foo}
+
+mfoo = fmap (.bar) $ Nothing
+
+bar = (Foo 1).bar
+
+fooplus f n = f{foo = f.bar + n}
+
+nestedFoo f = f.bar.bar.bar.bar.bar
+
+nestedFooUpdate f = f{bar.bar = f.bar} <> f{bar.bar.bar.bar}
+
+operatorUpdate f = f{(+) = 1}
diff --git a/data/examples/declaration/value/function/record/record-dot-out.hs b/data/examples/declaration/value/function/record/record-dot-out.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/declaration/value/function/record/record-dot-out.hs
@@ -0,0 +1,16 @@
+{-# LANGUAGE OverloadedRecordDot #-}
+{-# LANGUAGE OverloadedRecordUpdate #-}
+
+data Foo = Foo {bar :: Foo}
+
+mfoo = fmap (.bar) $ Nothing
+
+bar = (Foo 1).bar
+
+fooplus f n = f {foo = f.bar + n}
+
+nestedFoo f = f.bar.bar.bar.bar.bar
+
+nestedFooUpdate f = f {bar.bar = f.bar} <> f {bar.bar.bar.bar}
+
+operatorUpdate f = f {(+) = 1}
diff --git a/data/examples/declaration/value/function/record/record-dot.hs b/data/examples/declaration/value/function/record/record-dot.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/declaration/value/function/record/record-dot.hs
@@ -0,0 +1,16 @@
+{-# LANGUAGE OverloadedRecordDot #-}
+{-# LANGUAGE OverloadedRecordUpdate #-}
+
+data Foo = Foo { bar :: Foo }
+
+mfoo = fmap (.bar)   $ Nothing
+
+bar = (  Foo 1).bar
+
+fooplus f n = f{foo = f.bar + n}
+
+nestedFoo f = f.bar.bar.bar.bar.bar
+
+nestedFooUpdate f = f {bar.bar = f.bar } <> f {bar.bar.bar.bar}
+
+operatorUpdate f = f { (+) = 1 }
diff --git a/data/examples/module-header/empty-haddock-four-out.hs b/data/examples/module-header/empty-haddock-four-out.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/module-header/empty-haddock-four-out.hs
@@ -0,0 +1,1 @@
+module Test where
diff --git a/data/examples/module-header/empty-haddock-out.hs b/data/examples/module-header/empty-haddock-out.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/module-header/empty-haddock-out.hs
@@ -0,0 +1,1 @@
+module Test where
diff --git a/data/examples/module-header/empty-haddock.hs b/data/examples/module-header/empty-haddock.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/module-header/empty-haddock.hs
@@ -0,0 +1,3 @@
+-- |
+--
+module Test where
diff --git a/data/examples/other/comment-spacing-four-out.hs b/data/examples/other/comment-spacing-four-out.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/other/comment-spacing-four-out.hs
@@ -0,0 +1,7 @@
+-- |Something.
+foo ::
+    -- |Foo.
+    Int ->
+    -- |Bar.
+    IO ()
+foo _ = pure () -- comment
diff --git a/data/examples/other/comment-spacing-out.hs b/data/examples/other/comment-spacing-out.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/other/comment-spacing-out.hs
@@ -0,0 +1,7 @@
+-- |Something.
+foo ::
+  -- |Foo.
+  Int ->
+  -- |Bar.
+  IO ()
+foo _ = pure () -- comment
diff --git a/data/examples/other/comment-spacing.hs b/data/examples/other/comment-spacing.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/other/comment-spacing.hs
@@ -0,0 +1,7 @@
+-- |Something.
+foo ::
+  -- |Foo.
+  Int ->
+  -- |Bar.
+  IO ()
+foo _ = pure () --comment
diff --git a/data/examples/other/empty-haddock-four-out.hs b/data/examples/other/empty-haddock-four-out.hs
--- a/data/examples/other/empty-haddock-four-out.hs
+++ b/data/examples/other/empty-haddock-four-out.hs
@@ -1,5 +1,6 @@
-module Main where
+module Test (
+    test,
+) where
 
--- |
-foo :: Int
-foo = 5
+test ::
+    test
diff --git a/data/examples/other/empty-haddock-out.hs b/data/examples/other/empty-haddock-out.hs
--- a/data/examples/other/empty-haddock-out.hs
+++ b/data/examples/other/empty-haddock-out.hs
@@ -1,5 +1,7 @@
-module Main where
+module Test
+  ( test,
+  )
+where
 
--- |
-foo :: Int
-foo = 5
+test ::
+  test
diff --git a/data/examples/other/empty-haddock.hs b/data/examples/other/empty-haddock.hs
--- a/data/examples/other/empty-haddock.hs
+++ b/data/examples/other/empty-haddock.hs
@@ -1,6 +1,11 @@
-module Main where
-
 -- |
+module Test
+  ( -- |
+    test,
+  )
+where
 
-foo :: Int
-foo = 5
+-- |
+test ::
+  -- |
+  test
diff --git a/data/examples/other/invalid-haddock-four-out.hs b/data/examples/other/invalid-haddock-four-out.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/other/invalid-haddock-four-out.hs
@@ -0,0 +1,17 @@
+test = undefined
+  where
+    a ::
+        -- foo
+        Int ->
+        -- misplaced
+        Int
+    a = undefined
+
+test = undefined
+  where
+    -- Comment
+    a = undefined
+
+    -- A multiline
+    -- comment
+    b = b
diff --git a/data/examples/other/invalid-haddock-out.hs b/data/examples/other/invalid-haddock-out.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/other/invalid-haddock-out.hs
@@ -0,0 +1,17 @@
+test = undefined
+  where
+    a ::
+      -- foo
+      Int ->
+      -- misplaced
+      Int
+    a = undefined
+
+test = undefined
+  where
+    -- Comment
+    a = undefined
+
+    -- A multiline
+    -- comment
+    b = b
diff --git a/data/examples/other/invalid-haddock-weird-four-out.hs b/data/examples/other/invalid-haddock-weird-four-out.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/other/invalid-haddock-weird-four-out.hs
@@ -0,0 +1,3 @@
+{-# LANGUAGE TemplateHaskell #-}
+
+foo = foo -- # ${
diff --git a/data/examples/other/invalid-haddock-weird-out.hs b/data/examples/other/invalid-haddock-weird-out.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/other/invalid-haddock-weird-out.hs
@@ -0,0 +1,3 @@
+{-# LANGUAGE TemplateHaskell #-}
+
+foo = foo -- # ${
diff --git a/data/examples/other/invalid-haddock-weird.hs b/data/examples/other/invalid-haddock-weird.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/other/invalid-haddock-weird.hs
@@ -0,0 +1,3 @@
+{-# LANGUAGE TemplateHaskell #-}
+
+foo = foo -- |# ${
diff --git a/data/examples/other/invalid-haddock.hs b/data/examples/other/invalid-haddock.hs
new file mode 100644
--- /dev/null
+++ b/data/examples/other/invalid-haddock.hs
@@ -0,0 +1,17 @@
+test = undefined
+  where
+    a ::
+      -- ** foo
+      Int ->
+      -- | misplaced
+      Int
+    a = undefined
+
+test = undefined
+  where
+    -- | Comment
+    a = undefined
+
+    -- | A multiline
+    -- comment
+    b = b
diff --git a/data/examples/other/no-linear-arrows-four-out.hs b/data/examples/other/no-linear-arrows-four-out.hs
deleted file mode 100644
--- a/data/examples/other/no-linear-arrows-four-out.hs
+++ /dev/null
@@ -1,4 +0,0 @@
-type a % b = (a, b)
-
-type Foo a m b = a % m -> b
-type Bar a m b = a % m -> b
diff --git a/data/examples/other/no-linear-arrows-out.hs b/data/examples/other/no-linear-arrows-out.hs
deleted file mode 100644
--- a/data/examples/other/no-linear-arrows-out.hs
+++ /dev/null
@@ -1,5 +0,0 @@
-type a % b = (a, b)
-
-type Foo a m b = a % m -> b
-
-type Bar a m b = a % m -> b
diff --git a/data/examples/other/no-linear-arrows.hs b/data/examples/other/no-linear-arrows.hs
deleted file mode 100644
--- a/data/examples/other/no-linear-arrows.hs
+++ /dev/null
@@ -1,4 +0,0 @@
-type a % b = (a,b)
-
-type Foo a m b = a % m -> b
-type Bar a m b = a %m -> b
diff --git a/fourmolu.cabal b/fourmolu.cabal
--- a/fourmolu.cabal
+++ b/fourmolu.cabal
@@ -1,12 +1,12 @@
 cabal-version:      2.4
 name:               fourmolu
-version:            0.4.0.0
+version:            0.5.0.0
 license:            BSD-3-Clause
 license-file:       LICENSE.md
 maintainer:
     Matt Parsons <parsonsmatt@gmail.com>
     George Thomas <georgefsthomas@gmail.com>
-tested-with:        ghc ==8.8.4 ghc ==8.10.7 ghc ==9.0.1
+tested-with:        ghc ==8.10.7 ghc ==9.0.1 ghc ==9.2.1
 homepage:           https://github.com/parsonsmatt/fourmolu
 bug-reports:        https://github.com/parsonsmatt/fourmolu/issues
 synopsis:           A formatter for Haskell source code
@@ -39,7 +39,6 @@
         Ormolu.Exception
         Ormolu.Imports
         Ormolu.Parser
-        Ormolu.Parser.Anns
         Ormolu.Parser.CommentStream
         Ormolu.Parser.Pragma
         Ormolu.Parser.Result
@@ -82,16 +81,17 @@
     default-language: Haskell2010
     build-depends:
         Diff >=0.4 && <1.0,
-        aeson >=1.4.0.0 && <1.6,
+        aeson >=1.4.0.0 && <2.1,
         ansi-terminal >=0.10 && <1.0,
-        base >=4.12 && <5.0,
+        base >=4.14 && <5.0,
         bytestring >=0.2 && <0.12,
         containers >=0.5 && <0.7,
         directory >=1.3.3 && <1.4,
         dlist >=0.8 && <2.0,
+        array >=0.5 && <0.6,
         exceptions >=0.6 && <0.11,
         filepath >=1.4.2.1 && <1.5,
-        ghc-lib-parser >=9.0 && <9.1,
+        ghc-lib-parser >=9.2 && <9.3,
         HsYAML >=0.2 && <0.3,
         HsYAML-aeson >=0.2 && <0.3,
         mtl >=2.0 && <3.0,
@@ -99,7 +99,7 @@
         text >=0.2 && <1.3,
         filepath >=1.2 && <1.5,
         directory ^>=1.3,
-        Cabal ^>=3.4
+        Cabal >=3.6 && <3.7
 
     if flag(dev)
         ghc-options:
@@ -110,9 +110,6 @@
     else
         ghc-options: -O2 -Wall
 
-    if impl(ghc <8.10.0)
-        ghc-options: -fmax-pmcheck-iterations=3000000
-
 executable fourmolu
     main-is:          Main.hs
     hs-source-dirs:   app
@@ -124,7 +121,7 @@
         base >=4.12 && <5.0,
         directory >=1.3.3 && <1.4,
         filepath >=1.2 && <1.5,
-        ghc-lib-parser >=9.0 && <9.1,
+        ghc-lib-parser >=9.2 && <9.3,
         gitrev >=1.3 && <1.4,
         optparse-applicative >=0.14 && <0.17,
         text >=0.2 && <1.3
@@ -154,7 +151,7 @@
     default-language:   Haskell2010
     build-depends:
         fourmolu,
-        base >=4.12 && <5.0,
+        base >=4.14 && <5.0,
         containers >=0.5 && <0.7,
         directory ^>=1.3,
         filepath >=1.2 && <1.5,
diff --git a/src/GHC/DynFlags.hs b/src/GHC/DynFlags.hs
--- a/src/GHC/DynFlags.hs
+++ b/src/GHC/DynFlags.hs
@@ -24,12 +24,12 @@
       sFileSettings = FileSettings {},
       sTargetPlatform =
         Platform
-          { platformWordSize = PW8,
-            platformMini =
-              PlatformMini
-                { platformMini_arch = ArchUnknown,
-                  platformMini_os = OSUnknown
+          { platformArchOS =
+              ArchOS
+                { archOS_arch = ArchUnknown,
+                  archOS_OS = OSUnknown
                 },
+            platformWordSize = PW8,
             platformUnregisterised = True,
             platformByteOrder = LittleEndian,
             platformHasGnuNonexecStack = False,
@@ -37,11 +37,10 @@
             platformHasSubsectionsViaSymbols = False,
             platformIsCrossCompiling = False,
             platformLeadingUnderscore = False,
-            platformTablesNextToCode = False
+            platformTablesNextToCode = False,
+            platform_constants = Nothing
           },
       sPlatformMisc = PlatformMisc {},
-      sPlatformConstants =
-        PlatformConstants {pc_DYNAMIC_BY_DEFAULT = False, pc_WORD_SIZE = 8},
       sToolSettings =
         ToolSettings
           { toolSettings_opt_P_fingerprint = fingerprint0,
diff --git a/src/Ormolu.hs b/src/Ormolu.hs
--- a/src/Ormolu.hs
+++ b/src/Ormolu.hs
@@ -9,7 +9,9 @@
     Config (..),
     ColorMode (..),
     RegionIndices (..),
+    SourceType (..),
     defaultConfig,
+    detectSourceType,
     DynOption (..),
     PrinterOpts (..),
     PrinterOptsPartial,
@@ -37,10 +39,12 @@
 import Ormolu.Diff.Text
 import Ormolu.Exception
 import Ormolu.Parser
+import Ormolu.Parser.CommentStream (showCommentStream)
 import Ormolu.Parser.Result
 import Ormolu.Printer
 import Ormolu.Utils (showOutputable)
 import Ormolu.Utils.IO
+import System.FilePath
 
 -- | Format a 'String', return formatted version as 'Text'.
 --
@@ -52,6 +56,10 @@
 --       side-effects though.
 --     * Takes file name just to use it in parse error messages.
 --     * Throws 'OrmoluException'.
+--
+-- __NOTE__: The caller is responsible for setting the appropriate value in
+-- the 'cfgSourceType' field. Autodetection of source type won't happen
+-- here, see 'detectSourceType'.
 ormolu ::
   MonadIO m =>
   -- | Ormolu configuration
@@ -69,11 +77,14 @@
   when (cfgDebug cfg) $ do
     traceM "warnings:\n"
     traceM (concatMap showWarn warnings)
+    forM_ result0 $ \case
+      ParsedSnippet r -> traceM . showCommentStream . prCommentStream $ r
+      _ -> pure ()
   -- We're forcing 'txt' here because otherwise errors (such as messages
   -- about not-yet-supported functionality) will be thrown later when we try
   -- to parse the rendered code back, inside of GHC monad wrapper which will
   -- lead to error messages presenting the exceptions as GHC bugs.
-  let !txt = printModule result0 $ cfgPrinterOpts cfgWithIndices
+  let !txt = printSnippets result0 $ cfgPrinterOpts cfgWithIndices
   when (not (cfgUnsafe cfg) || cfgCheckIdempotence cfg) $ do
     -- Parse the result of pretty-printing again and make sure that AST
     -- is the same as AST of original snippet module span positions.
@@ -95,7 +106,7 @@
     -- Try re-formatting the formatted result to check if we get exactly
     -- the same output.
     when (cfgCheckIdempotence cfg) $
-      let txt2 = printModule result1 $ cfgPrinterOpts cfgWithIndices
+      let txt2 = printSnippets result1 $ cfgPrinterOpts cfgWithIndices
        in case diffText txt txt2 path of
             Nothing -> return ()
             Just diff ->
@@ -106,8 +117,9 @@
 -- | Load a file and format it. The file stays intact and the rendered
 -- version is returned as 'Text'.
 --
--- > ormoluFile cfg path =
--- >   liftIO (readFile path) >>= ormolu cfg path
+-- __NOTE__: The caller is responsible for setting the appropriate value in
+-- the 'cfgSourceType' field. Autodetection of source type won't happen
+-- here, see 'detectSourceType'.
 ormoluFile ::
   MonadIO m =>
   -- | Ormolu configuration
@@ -121,8 +133,9 @@
 
 -- | Read input from stdin and format it.
 --
--- > ormoluStdin cfg =
--- >   liftIO (hGetContents stdin) >>= ormolu cfg "<stdin>"
+-- __NOTE__: The caller is responsible for setting the appropriate value in
+-- the 'cfgSourceType' field. Autodetection of source type won't happen
+-- here, see 'detectSourceType'.
 ormoluStdin ::
   MonadIO m =>
   -- | Ormolu configuration
@@ -130,7 +143,7 @@
   -- | Resulting rendition
   m Text
 ormoluStdin cfg =
-  liftIO getContents >>= ormolu cfg "<stdin>"
+  getContentsUtf8 >>= ormolu cfg "<stdin>" . T.unpack
 
 ----------------------------------------------------------------------------
 -- Helpers
@@ -160,3 +173,10 @@
     [ showOutputable reason,
       showOutputable l
     ]
+
+-- | Detect 'SourceType' based on the file extension.
+detectSourceType :: FilePath -> SourceType
+detectSourceType mpath =
+  if takeExtension mpath == ".hsig"
+    then SignatureSource
+    else ModuleSource
diff --git a/src/Ormolu/Config.hs b/src/Ormolu/Config.hs
--- a/src/Ormolu/Config.hs
+++ b/src/Ormolu/Config.hs
@@ -13,6 +13,7 @@
     ColorMode (..),
     RegionIndices (..),
     RegionDeltas (..),
+    SourceType (..),
     defaultConfig,
     PrinterOpts (..),
     PrinterOptsPartial,
@@ -54,6 +55,14 @@
   )
 import System.FilePath (splitPath, (</>))
 
+-- | Type of sources that can be formatted by Ormolu.
+data SourceType
+  = -- | Consider the input as a regular Haskell module
+    ModuleSource
+  | -- | Consider the input as a Backpack module signature
+    SignatureSource
+  deriving (Eq, Show)
+
 -- | Ormolu configuration.
 data Config region = Config
   { -- | Dynamic options to pass to GHC parser
@@ -64,13 +73,15 @@
     cfgDebug :: !Bool,
     -- | Checks if re-formatting the result is idempotent
     cfgCheckIdempotence :: !Bool,
+    -- | How to parse the input (regular haskell module or Backpack file)
+    cfgSourceType :: !SourceType,
     -- | Whether to use colors and other features of ANSI terminals
     cfgColorMode :: !ColorMode,
     -- | Region selection
     cfgRegion :: !region,
     cfgPrinterOpts :: !PrinterOptsTotal
   }
-  deriving (Eq, Show, Functor)
+  deriving (Eq, Show, Functor, Generic)
 
 -- | Region selection as the combination of start and end line numbers.
 data RegionIndices = RegionIndices
@@ -99,6 +110,7 @@
       cfgUnsafe = False,
       cfgDebug = False,
       cfgCheckIdempotence = False,
+      cfgSourceType = ModuleSource,
       cfgColorMode = Auto,
       cfgRegion =
         RegionIndices
diff --git a/src/Ormolu/Diff/ParseResult.hs b/src/Ormolu/Diff/ParseResult.hs
--- a/src/Ormolu/Diff/ParseResult.hs
+++ b/src/Ormolu/Diff/ParseResult.hs
@@ -16,9 +16,10 @@
 where
 
 import Data.ByteString (ByteString)
+import Data.Foldable
 import Data.Generics
 import GHC.Hs
-import GHC.Types.Basic
+import GHC.Types.SourceText
 import GHC.Types.SrcLoc
 import Ormolu.Imports (normalizeImports)
 import Ormolu.Parser.CommentStream
@@ -31,6 +32,7 @@
     Same
   | -- | Two parse results differ
     Different [SrcSpan]
+  deriving (Show)
 
 instance Semigroup ParseResultDiff where
   Same <> a = a
@@ -54,17 +56,26 @@
     { prCommentStream = cstream1,
       prParsedSource = hs1
     } =
-    matchIgnoringSrcSpans cstream0 cstream1
+    diffCommentStream cstream0 cstream1
       <> matchIgnoringSrcSpans
         hs0 {hsmodImports = concat . normalizeImports False $ hsmodImports hs0}
         hs1 {hsmodImports = concat . normalizeImports False $ hsmodImports hs1}
 
+diffCommentStream :: CommentStream -> CommentStream -> ParseResultDiff
+diffCommentStream (CommentStream cs) (CommentStream cs')
+  | commentLines cs == commentLines cs' = Same
+  | otherwise = Different []
+  where
+    commentLines = concatMap (toList . unComment . unLoc)
+
 -- | Compare two values for equality disregarding the following aspects:
 --
 --     * 'SrcSpan's
 --     * ordering of import lists
 --     * style (ASCII vs Unicode) of arrows
 --     * LayoutInfo (brace style) in extension fields
+--     * Empty contexts in type classes
+--     * Parens around derived type classes
 matchIgnoringSrcSpans :: Data a => a -> a -> ParseResultDiff
 matchIgnoringSrcSpans a = genericQuery a
   where
@@ -74,36 +85,33 @@
       -- implement 'toConstr', so we have to deal with it in a special way.
       | Just x' <- cast x,
         Just y' <- cast y =
-        if x' == (y' :: ByteString)
-          then Same
-          else Different []
+          if x' == (y' :: ByteString)
+            then Same
+            else Different []
       | typeOf x == typeOf y,
         toConstr x == toConstr y =
-        mconcat $
-          gzipWithQ
-            ( genericQuery
-                `extQ` srcSpanEq
-                `extQ` commentEq
-                `extQ` sourceTextEq
-                `extQ` hsDocStringEq
-                `extQ` importDeclQualifiedStyleEq
-                `extQ` unicodeArrowStyleEq
-                `extQ` layoutInfoEq
-                `ext2Q` forLocated
-            )
-            x
-            y
+          mconcat $
+            gzipWithQ
+              ( genericQuery
+                  `extQ` srcSpanEq
+                  `ext1Q` epAnnEq
+                  `extQ` sourceTextEq
+                  `extQ` hsDocStringEq
+                  `extQ` importDeclQualifiedStyleEq
+                  `extQ` unicodeArrowStyleEq
+                  `extQ` layoutInfoEq
+                  `extQ` classDeclCtxEq
+                  `extQ` derivedTyClsParensEq
+                  `extQ` epaCommentsEq
+                  `ext2Q` forLocated
+              )
+              x
+              y
       | otherwise = Different []
     srcSpanEq :: SrcSpan -> GenericQ ParseResultDiff
     srcSpanEq _ _ = Same
-    commentEq :: Comment -> GenericQ ParseResultDiff
-    commentEq (Comment _ x) d =
-      case cast d :: Maybe Comment of
-        Nothing -> Different []
-        Just (Comment _ y) ->
-          if x == y
-            then Same
-            else Different []
+    epAnnEq :: EpAnn a -> GenericQ ParseResultDiff
+    epAnnEq _ _ = Same
     sourceTextEq :: SourceText -> GenericQ ParseResultDiff
     sourceTextEq _ _ = Same
     importDeclQualifiedStyleEq ::
@@ -128,7 +136,7 @@
       GenLocated e0 e1 ->
       GenericQ ParseResultDiff
     forLocated x@(L mspn _) y =
-      maybe id appendSpan (cast mspn) (genericQuery x y)
+      maybe id appendSpan (cast `ext1Q` (Just . locA) $ mspn) (genericQuery x y)
     appendSpan :: SrcSpan -> ParseResultDiff -> ParseResultDiff
     appendSpan s (Different ss) | fresh && helpful = Different (s : ss)
       where
@@ -138,8 +146,8 @@
     -- as we normalize arrow styles (e.g. -> vs →), we consider them equal here
     unicodeArrowStyleEq :: HsArrow GhcPs -> GenericQ ParseResultDiff
     unicodeArrowStyleEq (HsUnrestrictedArrow _) (castArrow -> Just (HsUnrestrictedArrow _)) = Same
-    unicodeArrowStyleEq (HsLinearArrow _) (castArrow -> Just (HsLinearArrow _)) = Same
-    unicodeArrowStyleEq (HsExplicitMult _ t) (castArrow -> Just (HsExplicitMult _ t')) = genericQuery t t'
+    unicodeArrowStyleEq (HsLinearArrow _ _) (castArrow -> Just (HsLinearArrow _ _)) = Same
+    unicodeArrowStyleEq (HsExplicitMult _ _ t) (castArrow -> Just (HsExplicitMult _ _ t')) = genericQuery t t'
     unicodeArrowStyleEq _ _ = Different []
     castArrow :: Typeable a => a -> Maybe (HsArrow GhcPs)
     castArrow = cast
@@ -147,3 +155,13 @@
     layoutInfoEq :: LayoutInfo -> GenericQ ParseResultDiff
     layoutInfoEq _ (cast -> Just (_ :: LayoutInfo)) = Same
     layoutInfoEq _ _ = Different []
+    classDeclCtxEq :: TyClDecl GhcPs -> GenericQ ParseResultDiff
+    classDeclCtxEq ClassDecl {tcdCtxt = Just (L _ []), ..} tc' = genericQuery ClassDecl {tcdCtxt = Nothing, ..} tc'
+    classDeclCtxEq tc tc' = genericQuery tc tc'
+    derivedTyClsParensEq :: DerivClauseTys GhcPs -> GenericQ ParseResultDiff
+    derivedTyClsParensEq (DctSingle NoExtField sigTy) dct' = genericQuery (DctMulti NoExtField [sigTy]) dct'
+    derivedTyClsParensEq dct dct' = genericQuery dct dct'
+    -- EpAnnComments ~ XCGRHSs GhcPs
+    epaCommentsEq :: EpAnnComments -> GenericQ ParseResultDiff
+    epaCommentsEq _ (cast -> Just (_ :: EpAnnComments)) = Same
+    epaCommentsEq _ _ = Different []
diff --git a/src/Ormolu/Imports.hs b/src/Ormolu/Imports.hs
--- a/src/Ormolu/Imports.hs
+++ b/src/Ormolu/Imports.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE RecordWildCards #-}
+{-# LANGUAGE TypeFamilies #-}
 
 -- | Manipulations on import lists.
 module Ormolu.Imports
@@ -15,17 +16,21 @@
 import Data.List (foldl', nubBy, sortBy, sortOn)
 import Data.Map.Strict (Map)
 import qualified Data.Map.Strict as M
-import GHC.Data.FastString (FastString)
-import GHC.Hs.Extension
+import GHC.Data.FastString
+import GHC.Hs
 import GHC.Hs.ImpExp as GHC
-import GHC.Types.Basic
 import GHC.Types.Name.Reader
+import GHC.Types.SourceText
 import GHC.Types.SrcLoc
 import GHC.Unit.Module.Name
 import GHC.Unit.Types
 import Ormolu.Utils (groupBy', notImplemented, separatedByBlank, showOutputable)
 
--- | Sort, group and normalize imports. Assumes input list is sorted by source location.
+-- | Sort, group and normalize imports.
+--
+-- Assumes input list is sorted by source location. Output list is not necessarily
+-- sorted by source location, so this function should be called at most once on a
+-- given input list.
 normalizeImports :: Bool -> [LImportDecl GhcPs] -> [[LImportDecl GhcPs]]
 normalizeImports preserveGroups =
   map
@@ -35,9 +40,10 @@
         . fmap (\x -> (importId x, g x))
     )
     . if preserveGroups
-      then map toList . groupBy' (\x y -> not $ separatedByBlank getLoc x y)
+      then map toList . groupBy' (\x y -> not $ separatedByBlank getLocA x y)
       else pure
   where
+    g :: LImportDecl GhcPs -> LImportDecl GhcPs
     g (L l ImportDecl {..}) =
       L
         l
@@ -69,7 +75,7 @@
 data ImportId = ImportId
   { importIsPrelude :: Bool,
     importIdName :: ModuleName,
-    importPkgQual :: Maybe FastString,
+    importPkgQual :: Maybe LexicalFastString,
     importSource :: IsBootInterface,
     importSafe :: Bool,
     importQualified :: Bool,
@@ -85,7 +91,7 @@
   ImportId
     { importIsPrelude = isPrelude,
       importIdName = moduleName,
-      importPkgQual = sl_fs <$> ideclPkgQual,
+      importPkgQual = LexicalFastString . sl_fs <$> ideclPkgQual,
       importSource = ideclSource,
       importSafe = ideclSafe,
       importQualified = case ideclQualified of
@@ -115,39 +121,38 @@
           alter = \case
             Nothing -> Just . L new_l $
               case new of
-                IEThingWith NoExtField n wildcard g flbl ->
-                  IEThingWith NoExtField n wildcard (normalizeWNames g) flbl
+                IEThingWith _ n wildcard g ->
+                  IEThingWith EpAnnNotUsed n wildcard (normalizeWNames g)
                 other -> other
             Just old ->
               let f = \case
-                    IEVar NoExtField n -> IEVar NoExtField n
-                    IEThingAbs NoExtField _ -> new
-                    IEThingAll NoExtField n -> IEThingAll NoExtField n
-                    IEThingWith NoExtField n wildcard g flbl ->
+                    IEVar _ n -> IEVar NoExtField n
+                    IEThingAbs _ _ -> new
+                    IEThingAll _ n -> IEThingAll EpAnnNotUsed n
+                    IEThingWith _ n wildcard g ->
                       case new of
                         IEVar NoExtField _ ->
                           error "Ormolu.Imports broken presupposition"
-                        IEThingAbs NoExtField _ ->
-                          IEThingWith NoExtField n wildcard g flbl
-                        IEThingAll NoExtField n' ->
-                          IEThingAll NoExtField n'
-                        IEThingWith NoExtField n' wildcard' g' flbl' ->
+                        IEThingAbs _ _ ->
+                          IEThingWith EpAnnNotUsed n wildcard g
+                        IEThingAll _ n' ->
+                          IEThingAll EpAnnNotUsed n'
+                        IEThingWith _ n' wildcard' g' ->
                           let combinedWildcard =
                                 case (wildcard, wildcard') of
                                   (IEWildcard _, _) -> IEWildcard 0
                                   (_, IEWildcard _) -> IEWildcard 0
                                   _ -> NoIEWildcard
                            in IEThingWith
-                                NoExtField
+                                EpAnnNotUsed
                                 n'
                                 combinedWildcard
                                 (normalizeWNames (g <> g'))
-                                flbl'
-                        IEModuleContents NoExtField _ -> notImplemented "IEModuleContents"
+                        IEModuleContents _ _ -> notImplemented "IEModuleContents"
                         IEGroup NoExtField _ _ -> notImplemented "IEGroup"
                         IEDoc NoExtField _ -> notImplemented "IEDoc"
                         IEDocNamed NoExtField _ -> notImplemented "IEDocNamed"
-                    IEModuleContents NoExtField _ -> notImplemented "IEModuleContents"
+                    IEModuleContents _ _ -> notImplemented "IEModuleContents"
                     IEGroup NoExtField _ _ -> notImplemented "IEGroup"
                     IEDoc NoExtField _ -> notImplemented "IEDoc"
                     IEDocNamed NoExtField _ -> notImplemented "IEDocNamed"
@@ -166,10 +171,10 @@
 getIewn :: IE GhcPs -> IEWrappedNameOrd
 getIewn = \case
   IEVar NoExtField x -> IEWrappedNameOrd (unLoc x)
-  IEThingAbs NoExtField x -> IEWrappedNameOrd (unLoc x)
-  IEThingAll NoExtField x -> IEWrappedNameOrd (unLoc x)
-  IEThingWith NoExtField x _ _ _ -> IEWrappedNameOrd (unLoc x)
-  IEModuleContents NoExtField _ -> notImplemented "IEModuleContents"
+  IEThingAbs _ x -> IEWrappedNameOrd (unLoc x)
+  IEThingAll _ x -> IEWrappedNameOrd (unLoc x)
+  IEThingWith _ x _ _ -> IEWrappedNameOrd (unLoc x)
+  IEModuleContents _ _ -> notImplemented "IEModuleContents"
   IEGroup NoExtField _ _ -> notImplemented "IEGroup"
   IEDoc NoExtField _ -> notImplemented "IEDoc"
   IEDocNamed NoExtField _ -> notImplemented "IEDocNamed"
@@ -181,14 +186,14 @@
 -- | Compare two @'IEWrapppedName' 'RdrName'@ things.
 compareIewn :: IEWrappedName RdrName -> IEWrappedName RdrName -> Ordering
 compareIewn (IEName x) (IEName y) = unLoc x `compareRdrName` unLoc y
-compareIewn (IEName _) (IEPattern _) = LT
-compareIewn (IEName _) (IEType _) = LT
-compareIewn (IEPattern _) (IEName _) = GT
-compareIewn (IEPattern x) (IEPattern y) = unLoc x `compareRdrName` unLoc y
-compareIewn (IEPattern _) (IEType _) = LT
-compareIewn (IEType _) (IEName _) = GT
-compareIewn (IEType _) (IEPattern _) = GT
-compareIewn (IEType x) (IEType y) = unLoc x `compareRdrName` unLoc y
+compareIewn (IEName _) (IEPattern _ _) = LT
+compareIewn (IEName _) (IEType _ _) = LT
+compareIewn (IEPattern _ _) (IEName _) = GT
+compareIewn (IEPattern _ x) (IEPattern _ y) = unLoc x `compareRdrName` unLoc y
+compareIewn (IEPattern _ _) (IEType _ _) = LT
+compareIewn (IEType _ _) (IEName _) = GT
+compareIewn (IEType _ _) (IEPattern _ _) = GT
+compareIewn (IEType _ x) (IEType _ y) = unLoc x `compareRdrName` unLoc y
 
 compareRdrName :: RdrName -> RdrName -> Ordering
 compareRdrName x y =
diff --git a/src/Ormolu/Parser.hs b/src/Ormolu/Parser.hs
--- a/src/Ormolu/Parser.hs
+++ b/src/Ormolu/Parser.hs
@@ -1,6 +1,8 @@
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE RecordWildCards #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE ViewPatterns #-}
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 
 -- | Parser for Haskell source code.
@@ -12,7 +14,9 @@
 
 import Control.Exception
 import Control.Monad.Except
+import Data.Char (isSpace)
 import Data.Functor
+import Data.Generics
 import qualified Data.List as L
 import qualified Data.List.NonEmpty as NE
 import Data.Ord (Down (Down))
@@ -22,19 +26,19 @@
 import qualified GHC.Data.StringBuffer as GHC
 import qualified GHC.Driver.CmdLine as GHC
 import GHC.Driver.Session as GHC
-import qualified GHC.Driver.Types as GHC
 import GHC.DynFlags (baseDynFlags)
+import GHC.Hs hiding (UnicodeSyntax)
 import GHC.LanguageExtensions.Type (Extension (..))
 import qualified GHC.Parser as GHC
+import GHC.Parser.Errors.Ppr (pprError)
 import qualified GHC.Parser.Header as GHC
 import qualified GHC.Parser.Lexer as GHC
+import qualified GHC.Types.SourceError as GHC (handleSourceError)
 import GHC.Types.SrcLoc
-import GHC.Unit.Module.Name
 import GHC.Utils.Error (Severity (..), errMsgSeverity, errMsgSpan)
 import qualified GHC.Utils.Panic as GHC
 import Ormolu.Config
 import Ormolu.Exception
-import Ormolu.Parser.Anns
 import Ormolu.Parser.CommentStream
 import Ormolu.Parser.Result
 import Ormolu.Processing.Common
@@ -89,25 +93,23 @@
   m (Either (SrcSpan, String) ParseResult)
 parseModuleSnippet Config {..} dynFlags path rawInput = liftIO $ do
   let (input, indent) = removeIndentation . linesInRegion cfgRegion $ rawInput
-  let useRecordDot =
-        "record-dot-preprocessor" == pgm_F dynFlags
-          || any
-            (("RecordDotPreprocessor" ==) . moduleNameString)
-            (pluginModNames dynFlags)
-      pStateErrors = \pstate ->
-        let errs = bagToList $ GHC.getErrorMessages pstate dynFlags
+  let pStateErrors = \pstate ->
+        let errs = fmap pprError . bagToList $ GHC.getErrorMessages pstate
             fixupErrSpan = incSpanLine (regionPrefixLength cfgRegion)
          in case L.sortOn (Down . SeverityOrd . errMsgSeverity) errs of
               [] -> Nothing
               err : _ ->
                 -- Show instance returns a short error message
                 Just (fixupErrSpan (errMsgSpan err), show err)
-      r = case runParser GHC.parseModule dynFlags path input of
+      parser = case cfgSourceType of
+        ModuleSource -> GHC.parseModule
+        SignatureSource -> GHC.parseSignature
+      r = case runParser parser dynFlags path input of
         GHC.PFailed pstate ->
           case pStateErrors pstate of
             Just err -> Left err
             Nothing -> error "PFailed does not have an error"
-        GHC.POk pstate (L _ hsModule) ->
+        GHC.POk pstate (L _ (normalizeModule -> hsModule)) ->
           case pStateErrors pstate of
             -- Some parse errors (pattern/arrow syntax in expr context)
             -- do not cause a parse error, but they are replaced with "_"
@@ -116,24 +118,54 @@
             Just err -> Left err
             Nothing ->
               let (stackHeader, pragmas, comments) =
-                    mkCommentStream input pstate
+                    mkCommentStream input hsModule
                in Right
                     ParseResult
                       { prParsedSource = hsModule,
-                        prAnns = mkAnns pstate,
+                        prSourceType = cfgSourceType,
                         prStackHeader = stackHeader,
                         prPragmas = pragmas,
                         prCommentStream = comments,
-                        prUseRecordDot = useRecordDot,
                         prExtensions = GHC.extensionFlags dynFlags,
                         prIndent = indent
                       }
   return r
 
+-- | Normalize a 'HsModule' by sorting its export lists, dropping
+-- blank comments, etc.
+normalizeModule :: HsModule -> HsModule
+normalizeModule hsmod =
+  everywhere
+    (mkT dropBlankTypeHaddocks)
+    hsmod
+      { hsmodImports =
+          hsmodImports hsmod,
+        hsmodDecls =
+          filter (not . isBlankDocD . unLoc) (hsmodDecls hsmod),
+        hsmodHaddockModHeader =
+          mfilter (not . isBlankDocString . unLoc) (hsmodHaddockModHeader hsmod),
+        hsmodExports =
+          (fmap . fmap) (filter (not . isBlankDocIE . unLoc)) (hsmodExports hsmod)
+      }
+  where
+    isBlankDocString = all isSpace . unpackHDS
+    isBlankDocD = \case
+      DocD _ s -> isBlankDocString $ docDeclDoc s
+      _ -> False
+    isBlankDocIE = \case
+      IEGroup _ _ s -> isBlankDocString s
+      IEDoc _ s -> isBlankDocString s
+      _ -> False
+
+    dropBlankTypeHaddocks = \case
+      L _ (HsDocTy _ ty (L _ ds)) :: LHsType GhcPs
+        | isBlankDocString ds -> ty
+      a -> a
+
 -- | Enable all language extensions that we think should be enabled by
 -- default for ease of use.
 setDefaultExts :: DynFlags -> DynFlags
-setDefaultExts flags = L.foldl' xopt_set flags autoExts
+setDefaultExts flags = L.foldl' xopt_set (lang_set flags (Just Haskell2010)) autoExts
   where
     autoExts = allExts L.\\ manualExts
     allExts = [minBound .. maxBound]
@@ -164,7 +196,9 @@
     -- decision of enabling this style is left to the user
     NegativeLiterals, -- with this, `- 1` and `-1` have differing AST
     LexicalNegation, -- implies NegativeLiterals
-    LinearTypes -- steals the (%) type operator in some cases
+    LinearTypes, -- steals the (%) type operator in some cases
+    OverloadedRecordDot, -- f.g parses differently
+    OverloadedRecordUpdate -- qualified fields are not supported
   ]
 
 -- | Run a 'GHC.P' computation.
@@ -183,7 +217,15 @@
   where
     location = mkRealSrcLoc (GHC.mkFastString filename) 1 1
     buffer = GHC.stringToStringBuffer input
-    parseState = GHC.mkPState flags buffer location
+    parseState = GHC.initParserState (opts flags) buffer location
+    opts =
+      GHC.mkParserOpts
+        <$> GHC.warningFlags
+        <*> GHC.extensionFlags
+        <*> GHC.safeImportsOn
+        <*> GHC.gopt GHC.Opt_Haddock
+        <*> GHC.gopt GHC.Opt_KeepRawTokenStream
+        <*> const True
 
 -- | Wrap GHC's 'Severity' to add 'Ord' instance.
 newtype SeverityOrd = SeverityOrd Severity
diff --git a/src/Ormolu/Parser/Anns.hs b/src/Ormolu/Parser/Anns.hs
deleted file mode 100644
--- a/src/Ormolu/Parser/Anns.hs
+++ /dev/null
@@ -1,42 +0,0 @@
--- | Ormolu-specific representation of GHC annotations.
-module Ormolu.Parser.Anns
-  ( Anns (..),
-    emptyAnns,
-    mkAnns,
-    lookupAnns,
-  )
-where
-
-import Data.Map.Strict (Map)
-import qualified Data.Map.Strict as M
-import GHC.Parser.Annotation
-import GHC.Parser.Lexer
-import GHC.Types.SrcLoc
-
--- | Ormolu-specific representation of GHC annotations.
-newtype Anns = Anns (Map RealSrcSpan [AnnKeywordId])
-  deriving (Eq)
-
--- | Empty 'Anns'.
-emptyAnns :: Anns
-emptyAnns = Anns M.empty
-
--- | Create 'Anns' from 'PState'.
-mkAnns ::
-  PState ->
-  Anns
-mkAnns pstate =
-  Anns $
-    M.fromListWith (++) (f <$> annotations pstate)
-  where
-    f ((rspn, kid), _) = (rspn, [kid])
-
--- | Lookup 'AnnKeywordId's corresponding to a given 'SrcSpan'.
-lookupAnns ::
-  -- | Span to lookup with
-  SrcSpan ->
-  -- | Collection of annotations
-  Anns ->
-  [AnnKeywordId]
-lookupAnns (RealSrcSpan rspn _) (Anns m) = M.findWithDefault [] rspn m
-lookupAnns (UnhelpfulSpan _) _ = []
diff --git a/src/Ormolu/Parser/CommentStream.hs b/src/Ormolu/Parser/CommentStream.hs
--- a/src/Ormolu/Parser/CommentStream.hs
+++ b/src/Ormolu/Parser/CommentStream.hs
@@ -1,6 +1,8 @@
 {-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
 {-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE TypeApplications #-}
 
 -- | Functions for working with comment stream.
 module Ormolu.Parser.CommentStream
@@ -17,14 +19,23 @@
   )
 where
 
+import Control.Monad ((<=<))
 import Data.Char (isSpace)
 import Data.Data (Data)
+import Data.Generics.Schemes
 import qualified Data.List as L
 import Data.List.NonEmpty (NonEmpty (..))
 import qualified Data.List.NonEmpty as NE
-import Data.Maybe (mapMaybe)
+import qualified Data.Map.Lazy as M
+import Data.Maybe
+import qualified Data.Set as S
+import GHC.Hs (HsModule)
+import GHC.Hs.Decls (HsDecl (..), LDocDecl, LHsDecl)
+import GHC.Hs.Doc
+import GHC.Hs.Extension
+import GHC.Hs.ImpExp
+import GHC.Parser.Annotation (EpAnnComments (..), getLocA)
 import qualified GHC.Parser.Annotation as GHC
-import qualified GHC.Parser.Lexer as GHC
 import GHC.Types.SrcLoc
 import Ormolu.Parser.Pragma
 import Ormolu.Utils (onTheSameLine, showOutputable)
@@ -37,19 +48,19 @@
 newtype CommentStream = CommentStream [RealLocated Comment]
   deriving (Eq, Data, Semigroup, Monoid)
 
--- | Create 'CommentStream' from 'GHC.PState'. The pragmas are
+-- | Create 'CommentStream' from 'HsModule'. The pragmas are
 -- removed from the 'CommentStream'.
 mkCommentStream ::
   -- | Original input
   String ->
-  -- | Parser state to use for comment extraction
-  GHC.PState ->
+  -- | Module to use for comment extraction
+  HsModule ->
   -- | Stack header, pragmas, and comment stream
   ( Maybe (RealLocated Comment),
     [([RealLocated Comment], Pragma)],
     CommentStream
   )
-mkCommentStream input pstate =
+mkCommentStream input hsModule =
   ( mstackHeader,
     pragmas,
     CommentStream comments
@@ -57,12 +68,49 @@
   where
     (comments, pragmas) = extractPragmas input rawComments1
     (rawComments1, mstackHeader) = extractStackHeader rawComments0
+
+    -- We want to extract all comments except _valid_ Haddock comments
     rawComments0 =
-      L.sortOn (realSrcSpanStart . getRealSrcSpan) $
-        mapMaybe (liftMaybe . fmap unAnnotationComment) (GHC.comment_q pstate)
-          ++ concatMap
-            (mapMaybe (liftMaybe . fmap unAnnotationComment) . snd)
-            (GHC.annotations_comments pstate)
+      fmap (uncurry L)
+        . M.toAscList
+        . flip M.withoutKeys validHaddockCommentSpans
+        . M.fromList
+        . fmap (\(L l a) -> (l, a))
+        $ allComments
+      where
+        -- All comments, including valid and invalid Haddock comments
+        allComments =
+          mapMaybe unAnnotationComment $
+            epAnnCommentsToList =<< listify (only @EpAnnComments) hsModule
+          where
+            epAnnCommentsToList = \case
+              EpaComments cs -> cs
+              EpaCommentsBalanced pcs fcs -> pcs <> fcs
+        -- All spans of valid Haddock comments
+        -- (everywhere where we use p_hsDoc{String,Name})
+        validHaddockCommentSpans =
+          S.fromList
+            . mapMaybe srcSpanToRealSrcSpan
+            . mconcat
+              [ fmap getLoc . listify (only @LHsDocString),
+                fmap getLocA . listify (only @(LDocDecl GhcPs)),
+                fmap getLocA . listify isDocD,
+                fmap getLocA . listify isIEDocLike
+              ]
+            $ hsModule
+          where
+            isDocD :: LHsDecl GhcPs -> Bool
+            isDocD = \case
+              L _ DocD {} -> True
+              _ -> False
+            isIEDocLike :: LIE GhcPs -> Bool
+            isIEDocLike = \case
+              L _ IEGroup {} -> True
+              L _ IEDoc {} -> True
+              L _ IEDocNamed {} -> True
+              _ -> False
+    only :: a -> Bool
+    only _ = True
 
 -- | Pretty-print a 'CommentStream'.
 showCommentStream :: CommentStream -> String
@@ -96,17 +144,16 @@
   where
     comment =
       L l . Comment atomsBefore . removeConseqBlanks . fmap dropTrailing $
-        if "{-" `L.isPrefixOf` s
-          then case NE.nonEmpty (lines s) of
-            Nothing -> s :| []
-            Just (x :| xs) ->
-              let getIndent y =
-                    if all isSpace y
-                      then startIndent
-                      else length (takeWhile isSpace y)
-                  n = minimum (startIndent : fmap getIndent xs)
-               in x :| (drop n <$> xs)
-          else s :| []
+        case NE.nonEmpty (lines s) of
+          Nothing -> s :| []
+          Just (x :| xs) ->
+            let getIndent y =
+                  if all isSpace y
+                    then startIndent
+                    else length (takeWhile isSpace y)
+                n = minimum (startIndent : fmap getIndent xs)
+                commentPrefix = if "{-" `L.isPrefixOf` s then "" else "-- "
+             in x :| ((commentPrefix <>) . drop n <$> xs)
     (atomsBefore, ls') =
       case dropWhile ((< commentLine) . fst) ls of
         [] -> (False, [])
@@ -181,21 +228,33 @@
                           then go' ls' [y'] ys
                           else go' ls [] xs
 
--- | Get a 'String' from 'GHC.AnnotationComment'.
-unAnnotationComment :: GHC.AnnotationComment -> Maybe String
-unAnnotationComment = \case
-  GHC.AnnDocCommentNext _ -> Nothing -- @-- |@
-  GHC.AnnDocCommentPrev _ -> Nothing -- @-- ^@
-  GHC.AnnDocCommentNamed _ -> Nothing -- @-- $@
-  GHC.AnnDocSection _ _ -> Nothing -- @-- *@
-  GHC.AnnDocOptions s -> Just s
-  GHC.AnnLineComment s -> Just s
-  GHC.AnnBlockComment s -> Just s
-
-liftMaybe :: GenLocated l (Maybe a) -> Maybe (GenLocated l a)
-liftMaybe = \case
-  L _ Nothing -> Nothing
-  L l (Just a) -> Just (L l a)
+-- | Extract @'RealLocated' 'String'@ from 'GHC.LEpaComment'.
+unAnnotationComment :: GHC.LEpaComment -> Maybe (RealLocated String)
+unAnnotationComment (L (GHC.Anchor anchor _) (GHC.EpaComment eck _)) = case eck of
+  GHC.EpaDocCommentNext s -> haddock s -- @-- |@
+  GHC.EpaDocCommentPrev s -> haddock s -- @-- ^@
+  GHC.EpaDocCommentNamed s -> haddock s -- @-- $@
+  GHC.EpaDocSection _ s -> haddock s -- @-- *@
+  GHC.EpaDocOptions s -> mkL s
+  GHC.EpaLineComment s -> mkL $
+    case take 3 s of
+      "-- " -> s
+      "---" -> s
+      _ -> let s' = insertAt " " s 3 in s'
+  GHC.EpaBlockComment s -> mkL s
+  GHC.EpaEofComment -> Nothing
+  where
+    mkL = Just . L anchor
+    insertAt x xs n = take (n - 1) xs ++ x ++ drop (n - 1) xs
+    haddock = mkL . dashPrefix <=< dropBlank
+      where
+        dashPrefix s = "--" <> spaceIfNecessary <> s
+          where
+            spaceIfNecessary = case s of
+              c : _ | c /= ' ' -> " "
+              _ -> ""
+        dropBlank :: String -> Maybe String
+        dropBlank s = if all isSpace s then Nothing else Just s
 
 -- | Remove consecutive blank lines.
 removeConseqBlanks :: NonEmpty String -> NonEmpty String
diff --git a/src/Ormolu/Parser/Pragma.hs b/src/Ormolu/Parser/Pragma.hs
--- a/src/Ormolu/Parser/Pragma.hs
+++ b/src/Ormolu/Parser/Pragma.hs
@@ -16,7 +16,6 @@
 import GHC.Data.StringBuffer
 import qualified GHC.Parser.Lexer as L
 import GHC.Types.SrcLoc
-import GHC.Unit.Module (stringToUnitId)
 
 -- | Ormolu's representation of pragmas.
 data Pragma
@@ -67,12 +66,11 @@
   where
     location = mkRealSrcLoc (mkFastString "") 1 1
     buffer = stringToStringBuffer input
-    parseState = L.mkPStatePure parserFlags buffer location
-    parserFlags =
-      L.mkParserFlags'
+    parseState = L.initParserState parserOpts buffer location
+    parserOpts =
+      L.mkParserOpts
         ES.empty
         ES.empty
-        (stringToUnitId "")
         True
         True
         True
diff --git a/src/Ormolu/Parser/Result.hs b/src/Ormolu/Parser/Result.hs
--- a/src/Ormolu/Parser/Result.hs
+++ b/src/Ormolu/Parser/Result.hs
@@ -12,7 +12,7 @@
 import GHC.Hs
 import GHC.LanguageExtensions.Type
 import GHC.Types.SrcLoc
-import Ormolu.Parser.Anns
+import Ormolu.Config (SourceType)
 import Ormolu.Parser.CommentStream
 import Ormolu.Parser.Pragma (Pragma)
 
@@ -21,18 +21,16 @@
 
 -- | A collection of data that represents a parsed module in Ormolu.
 data ParseResult = ParseResult
-  { -- | 'ParsedSource' from GHC
+  { -- | Parsed module or signature
     prParsedSource :: HsModule,
-    -- | Ormolu-specfic representation of annotations
-    prAnns :: Anns,
+    -- | Either regular module or signature file
+    prSourceType :: SourceType,
     -- | Stack header
     prStackHeader :: Maybe (RealLocated Comment),
     -- | Pragmas and the associated comments
     prPragmas :: [([RealLocated Comment], Pragma)],
     -- | Comment stream
     prCommentStream :: CommentStream,
-    -- | Whether or not record dot syntax is enabled
-    prUseRecordDot :: Bool,
     -- | Enabled extensions
     prExtensions :: EnumSet Extension,
     -- | Indentation level, can be non-zero in case of region formatting
diff --git a/src/Ormolu/Printer.hs b/src/Ormolu/Printer.hs
--- a/src/Ormolu/Printer.hs
+++ b/src/Ormolu/Printer.hs
@@ -4,7 +4,7 @@
 
 -- | Pretty-printer for Haskell AST.
 module Ormolu.Printer
-  ( printModule,
+  ( printSnippets,
     PrinterOpts (..),
   )
 where
@@ -18,14 +18,14 @@
 import Ormolu.Printer.SpanStream
 import Ormolu.Processing.Common
 
--- | Render a module.
-printModule ::
+-- | Render several source snippets.
+printSnippets ::
   -- | Result of parsing
   [SourceSnippet] ->
   PrinterOptsTotal ->
   -- | Resulting rendition
   Text
-printModule snippets printerOpts = T.concat . fmap printSnippet $ snippets
+printSnippets snippets printerOpts = T.concat . fmap printSnippet $ snippets
   where
     printSnippet = \case
       ParsedSnippet ParseResult {..} ->
@@ -38,8 +38,7 @@
             )
             (mkSpanStream prParsedSource)
             prCommentStream
-            prAnns
             printerOpts
-            prUseRecordDot
+            prSourceType
             prExtensions
       RawSnippet r -> r
diff --git a/src/Ormolu/Printer/Combinators.hs b/src/Ormolu/Printer/Combinators.hs
--- a/src/Ormolu/Printer/Combinators.hs
+++ b/src/Ormolu/Printer/Combinators.hs
@@ -10,7 +10,6 @@
   ( -- * The 'R' monad
     R,
     runR,
-    getAnns,
     getEnclosingSpan,
     isExtensionEnabled,
 
@@ -28,7 +27,6 @@
     inciHalf,
     located,
     located',
-    realLocated,
     switchLayout,
     Layout (..),
     vlayout,
@@ -50,7 +48,6 @@
     backticks,
     banana,
     braces,
-    recordDotBraces,
     brackets,
     parens,
     parensHash,
@@ -78,6 +75,7 @@
 import Ormolu.Config
 import Ormolu.Printer.Comments
 import Ormolu.Printer.Internal
+import Ormolu.Utils (HasSrcSpan (..))
 
 ----------------------------------------------------------------------------
 -- Basic
@@ -91,39 +89,33 @@
   R ()
 inciIf b m = if b then inci m else m
 
--- | Enter a 'Located' entity. This combinator handles outputting comments
+-- | Enter a 'GenLocated' entity. This combinator handles outputting comments
 -- and sets layout (single-line vs multi-line) for the inner computation.
 -- Roughly, the rule for using 'located' is that every time there is a
 -- 'Located' wrapper, it should be “discharged” with a corresponding
 -- 'located' invocation.
 located ::
-  -- | Thing to enter
-  Located a ->
-  -- | How to render inner value
-  (a -> R ()) ->
-  R ()
-located (L (UnhelpfulSpan _) a) f = f a
-located (L (RealSrcSpan l _) a) f = realLocated (L l a) f
-
--- | See 'located'
-realLocated ::
+  HasSrcSpan l =>
   -- | Thing to enter
-  RealLocated a ->
+  GenLocated l a ->
   -- | How to render inner value
   (a -> R ()) ->
   R ()
-realLocated (L l a) f = do
-  spitPrecedingComments l
-  withEnclosingSpan l $
-    switchLayout [RealSrcSpan l Nothing] (f a)
-  spitFollowingComments l
+located (L l' a) f = case loc' l' of
+  UnhelpfulSpan _ -> f a
+  RealSrcSpan l _ -> do
+    spitPrecedingComments l
+    withEnclosingSpan l $
+      switchLayout [RealSrcSpan l Nothing] (f a)
+    spitFollowingComments l
 
 -- | A version of 'located' with arguments flipped.
 located' ::
+  HasSrcSpan l =>
   -- | How to render inner value
   (a -> R ()) ->
   -- | Thing to enter
-  Located a ->
+  GenLocated l a ->
   R ()
 located' = flip located
 
@@ -236,23 +228,6 @@
 -- | Surround given entity by curly braces @{@ and  @}@.
 braces :: BracketStyle -> R () -> R ()
 braces = brackets_ False "{" "}"
-
--- | Surround record update fields which use RecordDot plugin entity by
--- curly braces @{@ and @}@.
---
--- @since 0.1.3.1
-recordDotBraces :: R () -> R ()
-recordDotBraces m = sitcc (vlayout singleLine multiLine)
-  where
-    singleLine = do
-      txt "{"
-      m
-      txt "}"
-    multiLine = do
-      txt "{"
-      sitcc m
-      newline
-      txt "}"
 
 -- | Surround given entity by square brackets @[@ and @]@.
 brackets :: BracketStyle -> R () -> R ()
diff --git a/src/Ormolu/Printer/Internal.hs b/src/Ormolu/Printer/Internal.hs
--- a/src/Ormolu/Printer/Internal.hs
+++ b/src/Ormolu/Printer/Internal.hs
@@ -19,12 +19,13 @@
     space,
     newline,
     declNewline,
-    useRecordDot,
+    askSourceType,
     inci,
     inciBy,
     inciByFrac,
     inciHalf,
     sitcc,
+    sitccIfTrailing,
     Layout (..),
     enterLayout,
     vlayout,
@@ -53,9 +54,6 @@
     setSpanMark,
     getSpanMark,
 
-    -- * Annotations
-    getAnns,
-
     -- * Extensions
     isExtensionEnabled,
   )
@@ -74,11 +72,9 @@
 import GHC.Data.EnumSet (EnumSet)
 import qualified GHC.Data.EnumSet as EnumSet
 import GHC.LanguageExtensions.Type
-import GHC.Parser.Annotation
 import GHC.Types.SrcLoc
 import GHC.Utils.Outputable (Outputable)
 import Ormolu.Config
-import Ormolu.Parser.Anns
 import Ormolu.Parser.CommentStream
 import Ormolu.Printer.SpanStream
 import Ormolu.Utils (showOutputable)
@@ -101,15 +97,13 @@
     rcLayout :: Layout,
     -- | Spans of enclosing elements of AST
     rcEnclosingSpans :: [RealSrcSpan],
-    -- | Collection of annotations
-    rcAnns :: Anns,
     -- | Whether the last expression in the layout can use braces
     rcCanUseBraces :: Bool,
-    -- | Whether the source could have used the record dot preprocessor
-    rcUseRecDot :: Bool,
     rcPrinterOpts :: PrinterOptsTotal,
     -- | Enabled extensions
-    rcExtensions :: EnumSet Extension
+    rcExtensions :: EnumSet Extension,
+    -- | Whether the source is a signature or a regular module
+    rcSourceType :: SourceType
   }
 
 -- | State context of 'R'.
@@ -173,16 +167,14 @@
   SpanStream ->
   -- | Comment stream
   CommentStream ->
-  -- | Annotations
-  Anns ->
   PrinterOptsTotal ->
-  -- | Use Record Dot Syntax
-  Bool ->
+  -- | Whether the source is a signature or a regular module
+  SourceType ->
   -- | Enabled extensions
   EnumSet Extension ->
   -- | Resulting rendition
   Text
-runR (R m) sstream cstream anns printerOpts recDot extensions =
+runR (R m) sstream cstream printerOpts sourceType extensions =
   TL.toStrict . toLazyText . scBuilder $ execState (runReaderT m rc) sc
   where
     rc =
@@ -190,11 +182,10 @@
         { rcIndent = 0,
           rcLayout = MultiLine,
           rcEnclosingSpans = [],
-          rcAnns = anns,
           rcCanUseBraces = False,
-          rcUseRecDot = recDot,
           rcPrinterOpts = printerOpts,
-          rcExtensions = extensions
+          rcExtensions = extensions,
+          rcSourceType = sourceType
         }
     sc =
       SC
@@ -395,9 +386,9 @@
             _ -> AfterNewline
         }
 
--- | Return 'True' if we should print record dot syntax.
-useRecordDot :: R Bool
-useRecordDot = R (asks rcUseRecDot)
+-- | Return the source type.
+askSourceType :: R SourceType
+askSourceType = R (asks rcSourceType)
 
 -- | Like 'inci', but indents by exactly the given number of steps.
 inciBy :: Int -> R () -> R ()
@@ -443,6 +434,14 @@
           }
   R (local modRC m)
 
+-- | When using trailing commas, same as 'sitcc'; when using leading commas,
+-- runs the input action unmodified.
+sitccIfTrailing :: R () -> R ()
+sitccIfTrailing x =
+  getPrinterOpt poCommaStyle >>= \case
+    Leading -> id x
+    Trailing -> sitcc x
+
 -- | Set 'Layout' for internal computation.
 enterLayout :: Layout -> R () -> R ()
 enterLayout l (R m) = R (local modRC m)
@@ -595,15 +594,6 @@
 -- | Get span of last output comment.
 getSpanMark :: R (Maybe SpanMark)
 getSpanMark = R (gets scSpanMark)
-
-----------------------------------------------------------------------------
--- Annotations
-
--- | For a given span return 'AnnKeywordId's associated with it.
-getAnns ::
-  SrcSpan ->
-  R [AnnKeywordId]
-getAnns spn = lookupAnns spn <$> R (asks rcAnns)
 
 ----------------------------------------------------------------------------
 -- Helpers for braces
diff --git a/src/Ormolu/Printer/Meat/Common.hs b/src/Ormolu/Printer/Meat/Common.hs
--- a/src/Ormolu/Printer/Meat/Common.hs
+++ b/src/Ormolu/Printer/Meat/Common.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NamedFieldPuns #-}
 {-# LANGUAGE OverloadedStrings #-}
 
 -- | Rendering of commonly useful bits.
@@ -7,7 +8,6 @@
     p_hsmodName,
     p_ieWrappedName,
     p_rdrName,
-    doesNotNeedExtraParens,
     p_qualName,
     p_infixDefHelper,
     p_hsDocString,
@@ -16,19 +16,19 @@
 where
 
 import Control.Monad
-import Data.List (intersperse, isPrefixOf)
+import Data.List (intersperse)
 import qualified Data.Text as T
 import GHC.Hs.Doc
 import GHC.Hs.ImpExp
 import GHC.Parser.Annotation
-import GHC.Types.Basic
-import GHC.Types.Name (nameStableString)
 import GHC.Types.Name.Occurrence (OccName (..))
 import GHC.Types.Name.Reader
+import GHC.Types.SourceText
 import GHC.Types.SrcLoc
 import GHC.Unit.Module.Name
 import Ormolu.Config
 import Ormolu.Printer.Combinators
+import Ormolu.Printer.Internal (askSourceType)
 import Ormolu.Utils
 
 -- | Data and type family style.
@@ -38,78 +38,56 @@
   | -- | Top-level declarations
     Free
 
+-- | Outputs the name of the module-like entity, preceeded by the correct prefix ("module" or "signature").
 p_hsmodName :: ModuleName -> R ()
 p_hsmodName mname = do
-  txt "module"
+  sourceType <- askSourceType
+  txt $ case sourceType of
+    ModuleSource -> "module"
+    SignatureSource -> "signature"
   space
   atom mname
 
 p_ieWrappedName :: IEWrappedName RdrName -> R ()
 p_ieWrappedName = \case
   IEName x -> p_rdrName x
-  IEPattern x -> do
+  IEPattern _ x -> do
     txt "pattern"
     space
     p_rdrName x
-  IEType x -> do
+  IEType _ x -> do
     txt "type"
     space
     p_rdrName x
 
--- | Render a @'Located' 'RdrName'@.
-p_rdrName :: Located RdrName -> R ()
-p_rdrName l@(L spn _) = located l $ \x -> do
-  ids <- getAnns spn
-  let backticksWrapper =
-        if AnnBackquote `elem` ids
-          then backticks
-          else id
-      parensWrapper =
-        if AnnOpenP `elem` ids
-          then parens N
-          else id
-      singleQuoteWrapper =
-        if AnnSimpleQuote `elem` ids
-          then \y -> do
-            txt "'"
-            y
-          else id
-      m =
-        case x of
-          Unqual occName ->
-            atom occName
-          Qual mname occName ->
-            p_qualName mname occName
-          Orig _ occName ->
-            -- This is used when GHC generates code that will be fed into
-            -- the renamer (e.g. from deriving clauses), but where we want
-            -- to say that something comes from given module which is not
-            -- specified in the source code, e.g. @Prelude.map@.
-            --
-            -- My current understanding is that the provided module name
-            -- serves no purpose for us and can be safely ignored.
-            atom occName
-          Exact name ->
-            atom name
-      m' = backticksWrapper (singleQuoteWrapper m)
-  if doesNotNeedExtraParens x
-    then m'
-    else parensWrapper m'
-
--- | Whether given name should not have parentheses around it. This is used
--- to detect e.g. tuples for which annotations will indicate parentheses,
--- but the parentheses are already part of the symbol, so no extra layer of
--- parentheses should be added. It also detects the [] literal.
-doesNotNeedExtraParens :: RdrName -> Bool
-doesNotNeedExtraParens = \case
-  Exact name ->
-    let s = nameStableString name
-     in -- I'm not sure this "stable string" is stable enough, but it looks
-        -- like this is the most robust way to tell if we're looking at
-        -- exactly this piece of built-in syntax.
-        ("$ghc-prim$GHC.Tuple$" `isPrefixOf` s)
-          || ("$ghc-prim$GHC.Types$[]" `isPrefixOf` s)
-  _ -> False
+-- | Render a @'LocatedN' 'RdrName'@.
+p_rdrName :: LocatedN RdrName -> R ()
+p_rdrName l = located l $ \x -> do
+  let wrapper = \case
+        EpAnn {anns} -> case anns of
+          NameAnnQuote {nann_quoted} -> tickPrefix . wrapper (ann nann_quoted)
+          NameAnn {nann_adornment = NameParens} -> parens N
+          NameAnn {nann_adornment = NameBackquotes} -> backticks
+          _ -> id
+        EpAnnNotUsed -> id
+  wrapper (ann . getLoc $ l) $ case x of
+    Unqual occName ->
+      atom occName
+    Qual mname occName ->
+      p_qualName mname occName
+    Orig _ occName ->
+      -- This is used when GHC generates code that will be fed into
+      -- the renamer (e.g. from deriving clauses), but where we want
+      -- to say that something comes from given module which is not
+      -- specified in the source code, e.g. @Prelude.map@.
+      --
+      -- My current understanding is that the provided module name
+      -- serves no purpose for us and can be safely ignored.
+      atom occName
+    Exact name ->
+      atom name
+  where
+    tickPrefix y = txt "'" *> y
 
 p_qualName :: ModuleName -> OccName -> R ()
 p_qualName mname occName = do
diff --git a/src/Ormolu/Printer/Meat/Declaration.hs b/src/Ormolu/Printer/Meat/Declaration.hs
--- a/src/Ormolu/Printer/Meat/Declaration.hs
+++ b/src/Ormolu/Printer/Meat/Declaration.hs
@@ -14,14 +14,13 @@
 import Data.List (sort)
 import Data.List.NonEmpty (NonEmpty (..), (<|))
 import qualified Data.List.NonEmpty as NE
-import GHC.Hs.Binds
-import GHC.Hs.Decls
-import GHC.Hs.Extension
-import GHC.Hs.Pat
+import GHC.Hs
 import GHC.Types.Name.Occurrence (occNameFS)
 import GHC.Types.Name.Reader
 import GHC.Types.SrcLoc
+import Ormolu.Config (SourceType (SignatureSource))
 import Ormolu.Printer.Combinators
+import Ormolu.Printer.Internal (askSourceType)
 import Ormolu.Printer.Meat.Common
 import Ormolu.Printer.Meat.Declaration.Annotation
 import Ormolu.Printer.Meat.Declaration.Class
@@ -59,11 +58,12 @@
 p_hsDeclsRespectGrouping = p_hsDecls' Respect
 
 p_hsDecls' :: UserGrouping -> FamilyStyle -> [LHsDecl GhcPs] -> R ()
-p_hsDecls' grouping style decls =
+p_hsDecls' grouping style decls = do
+  isSig <- (== SignatureSource) <$> askSourceType
   sepSemi id $
     -- Return a list of rendered declarations, adding a newline to separate
     -- groups.
-    case groupDecls decls of
+    case groupDecls isSig decls of
       [] -> []
       (x : xs) -> renderGroup x ++ concat (zipWith renderGroupWithPrev (x : xs) xs)
   where
@@ -75,7 +75,7 @@
         Disregard ->
           declNewline : renderGroup curr
         Respect ->
-          if separatedByBlankNE getLoc prev curr
+          if separatedByBlankNE getLocA prev curr
             || isDocumented prev
             || isDocumented curr
             then declNewline : renderGroup curr
@@ -90,47 +90,52 @@
     isHaddock _ = False
 
 -- | Group relevant declarations together.
-groupDecls :: [LHsDecl GhcPs] -> [NonEmpty (LHsDecl GhcPs)]
-groupDecls [] = []
-groupDecls (l@(L _ DocNext) : xs) =
+groupDecls ::
+  -- | Is the source a signature file?
+  Bool ->
+  -- | List of declarations
+  [LHsDecl GhcPs] ->
+  [NonEmpty (LHsDecl GhcPs)]
+groupDecls _ [] = []
+groupDecls isSig (l@(L _ DocNext) : xs) =
   -- If the first element is a doc string for next element, just include it
   -- in the next block:
-  case groupDecls xs of
+  case groupDecls isSig xs of
     [] -> [l :| []]
     (x : xs') -> (l <| x) : xs'
-groupDecls (header : xs) =
+groupDecls isSig (header : xs) =
   let (grp, rest) = flip span (zip (header : xs) xs) $ \(previous, current) ->
         let relevantToHdr = groupedDecls header current
             relevantToPrev = groupedDecls previous current
-            isDeclSeries = declSeries previous current
+            isDeclSeries = not isSig && declSeries previous current
          in isDeclSeries || relevantToHdr || relevantToPrev
-   in (header :| map snd grp) : groupDecls (map snd rest)
+   in (header :| map snd grp) : groupDecls isSig (map snd rest)
 
 p_hsDecl :: FamilyStyle -> HsDecl GhcPs -> R ()
 p_hsDecl style = \case
-  TyClD NoExtField x -> p_tyClDecl style x
-  ValD NoExtField x -> p_valDecl x
-  SigD NoExtField x -> p_sigDecl x
-  InstD NoExtField x -> p_instDecl style x
-  DerivD NoExtField x -> p_standaloneDerivDecl x
-  DefD NoExtField x -> p_defaultDecl x
-  ForD NoExtField x -> p_foreignDecl x
-  WarningD NoExtField x -> p_warnDecls x
-  AnnD NoExtField x -> p_annDecl x
-  RuleD NoExtField x -> p_ruleDecls x
-  SpliceD NoExtField x -> p_spliceDecl x
-  DocD NoExtField docDecl ->
+  TyClD _ x -> p_tyClDecl style x
+  ValD _ x -> p_valDecl x
+  SigD _ x -> p_sigDecl x
+  InstD _ x -> p_instDecl style x
+  DerivD _ x -> p_standaloneDerivDecl x
+  DefD _ x -> p_defaultDecl x
+  ForD _ x -> p_foreignDecl x
+  WarningD _ x -> p_warnDecls x
+  AnnD _ x -> p_annDecl x
+  RuleD _ x -> p_ruleDecls x
+  SpliceD _ x -> p_spliceDecl x
+  DocD _ docDecl ->
     case docDecl of
       DocCommentNext str -> p_hsDocString Pipe False (noLoc str)
       DocCommentPrev str -> p_hsDocString Caret False (noLoc str)
       DocCommentNamed name str -> p_hsDocString (Named name) False (noLoc str)
       DocGroup n str -> p_hsDocString (Asterisk n) False (noLoc str)
-  RoleAnnotD NoExtField x -> p_roleAnnot x
-  KindSigD NoExtField s -> p_standaloneKindSig s
+  RoleAnnotD _ x -> p_roleAnnot x
+  KindSigD _ s -> p_standaloneKindSig s
 
 p_tyClDecl :: FamilyStyle -> TyClDecl GhcPs -> R ()
 p_tyClDecl style = \case
-  FamDecl NoExtField x -> p_famDecl style x
+  FamDecl _ x -> p_famDecl style x
   SynDecl {..} -> p_synDecl tcdLName tcdFixity tcdTyVars tcdRhs
   DataDecl {..} ->
     p_dataDecl
@@ -154,16 +159,16 @@
 
 p_instDecl :: FamilyStyle -> InstDecl GhcPs -> R ()
 p_instDecl style = \case
-  ClsInstD NoExtField x -> p_clsInstDecl x
-  TyFamInstD NoExtField x -> p_tyFamInstDecl style x
-  DataFamInstD NoExtField x -> p_dataFamInstDecl style x
+  ClsInstD _ x -> p_clsInstDecl x
+  TyFamInstD _ x -> p_tyFamInstDecl style x
+  DataFamInstD _ x -> p_dataFamInstDecl style x
 
 -- | Determine if these declarations should be grouped together.
 groupedDecls ::
   LHsDecl GhcPs ->
   LHsDecl GhcPs ->
   Bool
-groupedDecls (L l_x x') (L l_y y') =
+groupedDecls (L (locA -> l_x) x') (L (locA -> l_y) y') =
   case (x', y') of
     (TypeSignature ns, FunctionBody ns') -> ns `intersects` ns'
     (TypeSignature ns, DefaultSignature ns') -> ns `intersects` ns'
@@ -174,11 +179,11 @@
     (x, DataDeclaration n) | Just ns <- isPragma x -> n `elem` ns
     (DataDeclaration n, x)
       | Just ns <- isPragma x ->
-        let f = occNameFS . rdrNameOcc in f n `elem` map f ns
+          let f = occNameFS . rdrNameOcc in f n `elem` map f ns
     (x, y)
       | Just ns <- isPragma x,
         Just ns' <- isPragma y ->
-        ns `intersects` ns'
+          ns `intersects` ns'
     (x, TypeSignature ns) | Just ns' <- isPragma x -> ns `intersects` ns'
     (TypeSignature ns, x) | Just ns' <- isPragma x -> ns `intersects` ns'
     (PatternSignature ns, Pattern n) -> n `elem` ns
@@ -200,8 +205,8 @@
   Bool
 declSeries (L _ x) (L _ y) =
   case (x, y) of
-    ( SigD NoExtField (TypeSig NoExtField _ _),
-      SigD NoExtField (TypeSig NoExtField _ _)
+    ( SigD _ (TypeSig _ _ _),
+      SigD _ (TypeSig _ _ _)
       ) -> True
     _ -> False
 
@@ -231,7 +236,7 @@
 -- Declarations that do not refer to names
 
 pattern Splice :: HsDecl GhcPs
-pattern Splice <- SpliceD NoExtField (SpliceDecl NoExtField _ _)
+pattern Splice <- SpliceD _ (SpliceDecl _ _ _)
 
 -- Declarations referring to a single name
 
@@ -248,17 +253,17 @@
   FamilyDeclaration,
   TypeSynonym ::
     RdrName -> HsDecl GhcPs
-pattern InlinePragma n <- SigD NoExtField (InlineSig NoExtField (L _ n) _)
-pattern SpecializePragma n <- SigD NoExtField (SpecSig NoExtField (L _ n) _ _)
-pattern SCCPragma n <- SigD NoExtField (SCCFunSig NoExtField _ (L _ n) _)
-pattern AnnTypePragma n <- AnnD NoExtField (HsAnnotation NoExtField _ (TypeAnnProvenance (L _ n)) _)
-pattern AnnValuePragma n <- AnnD NoExtField (HsAnnotation NoExtField _ (ValueAnnProvenance (L _ n)) _)
-pattern Pattern n <- ValD NoExtField (PatSynBind NoExtField (PSB _ (L _ n) _ _ _))
-pattern DataDeclaration n <- TyClD NoExtField (DataDecl NoExtField (L _ n) _ _ _)
-pattern ClassDeclaration n <- TyClD NoExtField (ClassDecl _ _ (L _ n) _ _ _ _ _ _ _ _)
-pattern KindSignature n <- KindSigD NoExtField (StandaloneKindSig NoExtField (L _ n) _)
-pattern FamilyDeclaration n <- TyClD NoExtField (FamDecl NoExtField (FamilyDecl NoExtField _ (L _ n) _ _ _ _))
-pattern TypeSynonym n <- TyClD NoExtField (SynDecl NoExtField (L _ n) _ _ _)
+pattern InlinePragma n <- SigD _ (InlineSig _ (L _ n) _)
+pattern SpecializePragma n <- SigD _ (SpecSig _ (L _ n) _ _)
+pattern SCCPragma n <- SigD _ (SCCFunSig _ _ (L _ n) _)
+pattern AnnTypePragma n <- AnnD _ (HsAnnotation _ _ (TypeAnnProvenance (L _ n)) _)
+pattern AnnValuePragma n <- AnnD _ (HsAnnotation _ _ (ValueAnnProvenance (L _ n)) _)
+pattern Pattern n <- ValD _ (PatSynBind _ (PSB _ (L _ n) _ _ _))
+pattern DataDeclaration n <- TyClD _ (DataDecl _ (L _ n) _ _ _)
+pattern ClassDeclaration n <- TyClD _ (ClassDecl _ _ (L _ n) _ _ _ _ _ _ _ _)
+pattern KindSignature n <- KindSigD _ (StandaloneKindSig _ (L _ n) _)
+pattern FamilyDeclaration n <- TyClD _ (FamDecl _ (FamilyDecl _ _ _ (L _ n) _ _ _ _))
+pattern TypeSynonym n <- TyClD _ (SynDecl _ (L _ n) _ _ _)
 
 -- Declarations which can refer to multiple names
 
@@ -276,47 +281,47 @@
 pattern WarningPragma n <- (warnSigRdrNames -> Just n)
 
 pattern DocNext, DocPrev :: HsDecl GhcPs
-pattern DocNext <- (DocD NoExtField (DocCommentNext _))
-pattern DocPrev <- (DocD NoExtField (DocCommentPrev _))
+pattern DocNext <- (DocD _ (DocCommentNext _))
+pattern DocPrev <- (DocD _ (DocCommentPrev _))
 
 sigRdrNames :: HsDecl GhcPs -> Maybe [RdrName]
-sigRdrNames (SigD NoExtField (TypeSig NoExtField ns _)) = Just $ map unLoc ns
-sigRdrNames (SigD NoExtField (ClassOpSig NoExtField _ ns _)) = Just $ map unLoc ns
-sigRdrNames (SigD NoExtField (PatSynSig NoExtField ns _)) = Just $ map unLoc ns
+sigRdrNames (SigD _ (TypeSig _ ns _)) = Just $ map unLoc ns
+sigRdrNames (SigD _ (ClassOpSig _ _ ns _)) = Just $ map unLoc ns
+sigRdrNames (SigD _ (PatSynSig _ ns _)) = Just $ map unLoc ns
 sigRdrNames _ = Nothing
 
 defSigRdrNames :: HsDecl GhcPs -> Maybe [RdrName]
-defSigRdrNames (SigD NoExtField (ClassOpSig NoExtField True ns _)) = Just $ map unLoc ns
+defSigRdrNames (SigD _ (ClassOpSig _ True ns _)) = Just $ map unLoc ns
 defSigRdrNames _ = Nothing
 
 funRdrNames :: HsDecl GhcPs -> Maybe [RdrName]
-funRdrNames (ValD NoExtField (FunBind NoExtField (L _ n) _ _)) = Just [n]
-funRdrNames (ValD NoExtField (PatBind NoExtField (L _ n) _ _)) = Just $ patBindNames n
+funRdrNames (ValD _ (FunBind _ (L _ n) _ _)) = Just [n]
+funRdrNames (ValD _ (PatBind _ (L _ n) _ _)) = Just $ patBindNames n
 funRdrNames _ = Nothing
 
 patSigRdrNames :: HsDecl GhcPs -> Maybe [RdrName]
-patSigRdrNames (SigD NoExtField (PatSynSig NoExtField ns _)) = Just $ map unLoc ns
+patSigRdrNames (SigD _ (PatSynSig _ ns _)) = Just $ map unLoc ns
 patSigRdrNames _ = Nothing
 
 warnSigRdrNames :: HsDecl GhcPs -> Maybe [RdrName]
-warnSigRdrNames (WarningD NoExtField (Warnings NoExtField _ ws)) = Just $
-  flip concatMap ws $ \(L _ (Warning NoExtField ns _)) -> map unLoc ns
+warnSigRdrNames (WarningD _ (Warnings _ _ ws)) = Just $
+  flip concatMap ws $ \(L _ (Warning _ ns _)) -> map unLoc ns
 warnSigRdrNames _ = Nothing
 
 patBindNames :: Pat GhcPs -> [RdrName]
-patBindNames (TuplePat NoExtField ps _) = concatMap (patBindNames . unLoc) ps
-patBindNames (VarPat NoExtField (L _ n)) = [n]
-patBindNames (WildPat NoExtField) = []
-patBindNames (LazyPat NoExtField (L _ p)) = patBindNames p
-patBindNames (BangPat NoExtField (L _ p)) = patBindNames p
-patBindNames (ParPat NoExtField (L _ p)) = patBindNames p
-patBindNames (ListPat NoExtField ps) = concatMap (patBindNames . unLoc) ps
-patBindNames (AsPat NoExtField (L _ n) (L _ p)) = n : patBindNames p
-patBindNames (SumPat NoExtField (L _ p) _ _) = patBindNames p
-patBindNames (ViewPat NoExtField _ (L _ p)) = patBindNames p
-patBindNames (SplicePat NoExtField _) = []
-patBindNames (LitPat NoExtField _) = []
+patBindNames (TuplePat _ ps _) = concatMap (patBindNames . unLoc) ps
+patBindNames (VarPat _ (L _ n)) = [n]
+patBindNames (WildPat _) = []
+patBindNames (LazyPat _ (L _ p)) = patBindNames p
+patBindNames (BangPat _ (L _ p)) = patBindNames p
+patBindNames (ParPat _ (L _ p)) = patBindNames p
+patBindNames (ListPat _ ps) = concatMap (patBindNames . unLoc) ps
+patBindNames (AsPat _ (L _ n) (L _ p)) = n : patBindNames p
+patBindNames (SumPat _ (L _ p) _ _) = patBindNames p
+patBindNames (ViewPat _ _ (L _ p)) = patBindNames p
+patBindNames (SplicePat _ _) = []
+patBindNames (LitPat _ _) = []
 patBindNames (SigPat _ (L _ p) _) = patBindNames p
-patBindNames (NPat NoExtField _ _ _) = []
-patBindNames (NPlusKPat NoExtField (L _ n) _ _ _ _) = [n]
-patBindNames (ConPat NoExtField _ d) = concatMap (patBindNames . unLoc) (hsConPatArgs d)
+patBindNames (NPat _ _ _ _) = []
+patBindNames (NPlusKPat _ (L _ n) _ _ _ _) = [n]
+patBindNames (ConPat _ _ d) = concatMap (patBindNames . unLoc) (hsConPatArgs d)
diff --git a/src/Ormolu/Printer/Meat/Declaration/Annotation.hs b/src/Ormolu/Printer/Meat/Declaration/Annotation.hs
--- a/src/Ormolu/Printer/Meat/Declaration/Annotation.hs
+++ b/src/Ormolu/Printer/Meat/Declaration/Annotation.hs
@@ -6,20 +6,19 @@
   )
 where
 
-import GHC.Hs.Decls
-import GHC.Hs.Extension
+import GHC.Hs
 import Ormolu.Printer.Combinators
 import Ormolu.Printer.Meat.Common
 import Ormolu.Printer.Meat.Declaration.Value
 
 p_annDecl :: AnnDecl GhcPs -> R ()
-p_annDecl (HsAnnotation NoExtField _ annProv expr) =
+p_annDecl (HsAnnotation _ _ annProv expr) =
   pragma "ANN" . inci $ do
     p_annProv annProv
     breakpoint
     located expr p_hsExpr
 
-p_annProv :: AnnProvenance (IdP GhcPs) -> R ()
+p_annProv :: AnnProvenance GhcPs -> R ()
 p_annProv = \case
   ValueAnnProvenance name -> p_rdrName name
   TypeAnnProvenance name -> txt "type" >> space >> p_rdrName name
diff --git a/src/Ormolu/Printer/Meat/Declaration/Class.hs b/src/Ormolu/Printer/Meat/Declaration/Class.hs
--- a/src/Ormolu/Printer/Meat/Declaration/Class.hs
+++ b/src/Ormolu/Printer/Meat/Declaration/Class.hs
@@ -13,12 +13,9 @@
 import Data.Foldable
 import Data.Function (on)
 import Data.List (sortBy)
-import GHC.Core.Class
-import GHC.Hs.Binds
-import GHC.Hs.Decls
-import GHC.Hs.Extension
-import GHC.Hs.Type
-import GHC.Types.Basic
+import Data.Maybe
+import GHC.Hs
+import GHC.Types.Fixity
 import GHC.Types.Name.Reader
 import GHC.Types.SrcLoc
 import Ormolu.Config
@@ -28,32 +25,32 @@
 import Ormolu.Printer.Meat.Type
 
 p_classDecl ::
-  LHsContext GhcPs ->
-  Located RdrName ->
+  Maybe (LHsContext GhcPs) ->
+  LocatedN RdrName ->
   LHsQTyVars GhcPs ->
   LexicalFixity ->
-  [Located (FunDep (Located RdrName))] ->
+  [LHsFunDep GhcPs] ->
   [LSig GhcPs] ->
   LHsBinds GhcPs ->
   [LFamilyDecl GhcPs] ->
   [LTyFamDefltDecl GhcPs] ->
-  [LDocDecl] ->
+  [LDocDecl GhcPs] ->
   R ()
 p_classDecl ctx name HsQTvs {..} fixity fdeps csigs cdefs cats catdefs cdocs = do
-  let variableSpans = getLoc <$> hsq_explicit
-      signatureSpans = getLoc name : variableSpans
-      dependencySpans = getLoc <$> fdeps
-      combinedSpans = getLoc ctx : (signatureSpans ++ dependencySpans)
+  let variableSpans = getLocA <$> hsq_explicit
+      signatureSpans = getLocA name : variableSpans
+      dependencySpans = getLocA <$> fdeps
+      combinedSpans = maybeToList (getLocA <$> ctx) ++ signatureSpans ++ dependencySpans
       -- GHC's AST does not necessarily store each kind of element in source
       -- location order. This happens because different declarations are stored
       -- in different lists. Consequently, to get all the declarations in proper
       -- order, they need to be manually sorted.
-      sigs = (getLoc &&& fmap (SigD NoExtField)) <$> csigs
-      vals = (getLoc &&& fmap (ValD NoExtField)) <$> toList cdefs
-      tyFams = (getLoc &&& fmap (TyClD NoExtField . FamDecl NoExtField)) <$> cats
-      docs = (getLoc &&& fmap (DocD NoExtField)) <$> cdocs
+      sigs = (getLocA &&& fmap (SigD NoExtField)) <$> csigs
+      vals = (getLocA &&& fmap (ValD NoExtField)) <$> toList cdefs
+      tyFams = (getLocA &&& fmap (TyClD NoExtField . FamDecl NoExtField)) <$> cats
+      docs = (getLocA &&& fmap (DocD NoExtField)) <$> cdocs
       tyFamDefs =
-        ( getLoc &&& fmap (InstD NoExtField . TyFamInstD NoExtField)
+        ( getLocA &&& fmap (InstD NoExtField . TyFamInstD NoExtField)
         )
           <$> catdefs
       allDecls =
@@ -62,7 +59,7 @@
   switchLayout combinedSpans $ do
     breakpoint
     inci $ do
-      p_classContext ctx
+      for_ ctx p_classContext
       switchLayout signatureSpans $
         p_infixDefHelper
           (isInfix fixity)
@@ -84,7 +81,7 @@
   txt "=>"
   breakpoint
 
-p_classFundeps :: [Located (FunDep (Located RdrName))] -> R ()
+p_classFundeps :: [LHsFunDep GhcPs] -> R ()
 p_classFundeps fdeps = unless (null fdeps) $ do
   breakpoint
   txt "|"
@@ -96,8 +93,8 @@
         Leading -> id x
         Trailing -> inci x
 
-p_funDep :: FunDep (Located RdrName) -> R ()
-p_funDep (before, after) = do
+p_funDep :: FunDep GhcPs -> R ()
+p_funDep (FunDep _ before after) = do
   sep space p_rdrName before
   space
   txt "->"
diff --git a/src/Ormolu/Printer/Meat/Declaration/Data.hs b/src/Ormolu/Printer/Meat/Declaration/Data.hs
--- a/src/Ormolu/Printer/Meat/Declaration/Data.hs
+++ b/src/Ormolu/Printer/Meat/Declaration/Data.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE BlockArguments #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE OverloadedStrings #-}
@@ -12,11 +13,9 @@
 import Control.Monad
 import Data.Maybe (isJust, maybeToList)
 import qualified Data.Text as Text
-import GHC.Hs.Decls
-import GHC.Hs.Extension
-import GHC.Hs.Type
-import GHC.Parser.Annotation
-import GHC.Types.Basic
+import Data.Void
+import GHC.Hs
+import GHC.Types.Fixity
 import GHC.Types.ForeignCall
 import GHC.Types.Name.Reader
 import GHC.Types.SrcLoc
@@ -24,13 +23,12 @@
 import Ormolu.Printer.Combinators
 import Ormolu.Printer.Meat.Common
 import Ormolu.Printer.Meat.Type
-import Ormolu.Utils
 
 p_dataDecl ::
   -- | Whether to format as data family
   FamilyStyle ->
   -- | Type constructor
-  Located RdrName ->
+  LocatedN RdrName ->
   -- | Type patterns
   HsTyPats GhcPs ->
   -- | Lexical fixity
@@ -54,8 +52,8 @@
         Just (Header h _) -> space *> p_sourceText h
       p_sourceText type_
       txt " #-}"
-  let constructorSpans = getLoc name : fmap lhsTypeArgSrcSpan tpats
-      sigSpans = maybeToList . fmap getLoc $ dd_kindSig
+  let constructorSpans = getLocA name : fmap lhsTypeArgSrcSpan tpats
+      sigSpans = maybeToList . fmap getLocA $ dd_kindSig
       declHeaderSpans = constructorSpans ++ sigSpans
   switchLayout declHeaderSpans $ do
     breakpoint
@@ -80,7 +78,7 @@
           txt "where"
         breakpoint
         sepSemi (located' (p_conDecl False)) dd_cons
-      else switchLayout (getLoc name : (getLoc <$> dd_cons)) . inci $ do
+      else switchLayout (getLocA name : (getLocA <$> dd_cons)) . inci $ do
         let singleConstRec = isSingleConstRec dd_cons
         if singleConstRec
           then space
@@ -100,9 +98,8 @@
                 then id
                 else sitcc
         sep s (sitcc' . located' (p_conDecl singleConstRec)) dd_cons
-  unless (null $ unLoc dd_derivs) breakpoint
-  inci . located dd_derivs $ \xs ->
-    sep newline (located' p_hsDerivingClause) xs
+  unless (null dd_derivs) breakpoint
+  inci $ sep newline (located' p_hsDerivingClause) dd_derivs
 
 p_conDecl ::
   Bool ->
@@ -112,11 +109,14 @@
   ConDeclGADT {..} -> do
     mapM_ (p_hsDocString Pipe True) con_doc
     let conDeclSpn =
-          fmap getLoc con_names
-            <> [getLoc con_forall]
-            <> fmap getLoc con_qvars
-            <> maybeToList (fmap getLoc con_mb_cxt)
-            <> conArgsSpans con_args
+          fmap getLocA con_names
+            <> [getLocA con_bndrs]
+            <> maybeToList (fmap getLocA con_mb_cxt)
+            <> conArgsSpans
+          where
+            conArgsSpans = case con_g_args of
+              PrefixConGADT xs -> getLocA . hsScaledThing <$> xs
+              RecConGADT x -> [getLocA x]
     switchLayout conDeclSpn $ do
       case con_names of
         [] -> return ()
@@ -133,52 +133,53 @@
                 then newline
                 else breakpoint
         interArgBreak
-        conTy <- case con_args of
-          PrefixCon xs ->
-            let go (HsScaled a b) t = L (combineLocs t b) (HsFunTy NoExtField a b t)
-             in pure $ foldr go con_res_ty xs
-          RecCon r@(L l rs) ->
-            pure
-              . L (combineLocs r con_res_ty)
-              $ HsFunTy
-                NoExtField
-                (HsUnrestrictedArrow NormalSyntax)
-                (L l $ HsRecTy NoExtField rs)
-                con_res_ty
-          InfixCon _ _ -> notImplemented "InfixCon" -- NOTE(amesgen) should be unreachable
-        let qualTy = case con_mb_cxt of
+        let conTy = case con_g_args of
+              PrefixConGADT xs ->
+                let go (HsScaled a b) t = addCLocAA t b (HsFunTy EpAnnNotUsed a b t)
+                 in foldr go con_res_ty xs
+              RecConGADT r ->
+                addCLocAA r con_res_ty $
+                  HsFunTy
+                    EpAnnNotUsed
+                    (HsUnrestrictedArrow NormalSyntax)
+                    (la2la $ HsRecTy EpAnnNotUsed <$> r)
+                    con_res_ty
+            qualTy = case con_mb_cxt of
               Nothing -> conTy
               Just qs ->
-                L (combineLocs qs conTy) $
-                  HsQualTy NoExtField qs conTy
-        let quantifiedTy =
-              if unLoc con_forall
-                then
-                  L (combineLocs con_forall qualTy) $
-                    HsForAllTy NoExtField (mkHsForAllInvisTele con_qvars) qualTy
-                else qualTy
+                addCLocAA qs conTy $
+                  HsQualTy NoExtField (Just qs) conTy
+            quantifiedTy =
+              addCLocAA con_bndrs qualTy $
+                hsOuterTyVarBndrsToHsType (unLoc con_bndrs) qualTy
         p_hsType (unLoc quantifiedTy)
   ConDeclH98 {..} -> do
     mapM_ (p_hsDocString Pipe True) con_doc
     let conDeclWithContextSpn =
-          [getLoc con_forall]
-            <> fmap getLoc con_ex_tvs
-            <> maybeToList (fmap getLoc con_mb_cxt)
+          [RealSrcSpan real Nothing | AddEpAnn AnnForall (EpaSpan real) <- epAnnAnns con_ext]
+          <> fmap getLocA con_ex_tvs
+            <> maybeToList (fmap getLocA con_mb_cxt)
             <> conDeclSpn
-        conDeclSpn =
-          getLoc con_name : conArgsSpans con_args
+        conDeclSpn = getLocA con_name : conArgsSpans
+          where
+            conArgsSpans = case con_args of
+              PrefixCon [] xs -> getLocA . hsScaledThing <$> xs
+              PrefixCon (v : _) _ -> absurd v
+              RecCon l -> [getLocA l]
+              InfixCon x y -> getLocA . hsScaledThing <$> [x, y]
     switchLayout conDeclWithContextSpn $ do
-      when (unLoc con_forall) $ do
+      when con_forall $ do
         p_forallBndrs ForAllInvis p_hsTyVarBndr con_ex_tvs
         breakpoint
         indent <- getPrinterOpt poIndentation
         vlayout (pure ()) . txt $ Text.replicate (indent - 2) " "
       forM_ con_mb_cxt p_lhsContext
       switchLayout conDeclSpn $ case con_args of
-        PrefixCon xs -> do
+        PrefixCon [] xs -> do
           p_rdrName con_name
           unless (null xs) breakpoint
           inci . sitcc $ sep breakpoint (sitcc . located' p_hsTypePostDoc) (hsScaledThing <$> xs)
+        PrefixCon (v : _) _ -> absurd v
         RecCon l -> do
           p_rdrName con_name
           breakpoint
@@ -191,15 +192,6 @@
             space
             located y p_hsType
 
-conArgsSpans :: HsConDeclDetails GhcPs -> [SrcSpan]
-conArgsSpans = \case
-  PrefixCon xs ->
-    getLoc . hsScaledThing <$> xs
-  RecCon l ->
-    [getLoc l]
-  InfixCon x y ->
-    getLoc . hsScaledThing <$> [x, y]
-
 p_lhsContext ::
   LHsContext GhcPs ->
   R ()
@@ -222,39 +214,39 @@
 p_hsDerivingClause HsDerivingClause {..} = do
   txt "deriving"
   let derivingWhat = located deriv_clause_tys $ \case
-        [] -> txt "()"
-        xs ->
+        DctSingle NoExtField sigTy -> parens N $ located sigTy p_hsSigType
+        DctMulti NoExtField sigTys ->
           parens N $
             sep
               commaDel
-              (sitcc . located' p_hsType . hsib_body)
-              xs
+              (sitcc . located' p_hsSigType)
+              sigTys
   space
   case deriv_clause_strategy of
     Nothing -> do
       breakpoint
       inci derivingWhat
     Just (L _ a) -> case a of
-      StockStrategy -> do
+      StockStrategy _ -> do
         txt "stock"
         breakpoint
         inci derivingWhat
-      AnyclassStrategy -> do
+      AnyclassStrategy _ -> do
         txt "anyclass"
         breakpoint
         inci derivingWhat
-      NewtypeStrategy -> do
+      NewtypeStrategy _ -> do
         txt "newtype"
         breakpoint
         inci derivingWhat
-      ViaStrategy HsIB {..} -> do
+      ViaStrategy (XViaStrategyPs _ sigTy) -> do
         breakpoint
         inci $ do
           derivingWhat
           breakpoint
           txt "via"
           space
-          located hsib_body p_hsType
+          located sigTy p_hsSigType
 
 ----------------------------------------------------------------------------
 -- Helpers
diff --git a/src/Ormolu/Printer/Meat/Declaration/Default.hs b/src/Ormolu/Printer/Meat/Declaration/Default.hs
--- a/src/Ormolu/Printer/Meat/Declaration/Default.hs
+++ b/src/Ormolu/Printer/Meat/Declaration/Default.hs
@@ -6,13 +6,12 @@
   )
 where
 
-import GHC.Hs.Decls
-import GHC.Hs.Extension
+import GHC.Hs
 import Ormolu.Printer.Combinators
 import Ormolu.Printer.Meat.Type
 
 p_defaultDecl :: DefaultDecl GhcPs -> R ()
-p_defaultDecl (DefaultDecl NoExtField ts) = do
+p_defaultDecl (DefaultDecl _ ts) = do
   txt "default"
   breakpoint
   inci . parens N $
diff --git a/src/Ormolu/Printer/Meat/Declaration/Foreign.hs b/src/Ormolu/Printer/Meat/Declaration/Foreign.hs
--- a/src/Ormolu/Printer/Meat/Declaration/Foreign.hs
+++ b/src/Ormolu/Printer/Meat/Declaration/Foreign.hs
@@ -8,9 +8,7 @@
 where
 
 import Control.Monad
-import GHC.Hs.Decls
-import GHC.Hs.Extension
-import GHC.Hs.Type
+import GHC.Hs
 import GHC.Types.ForeignCall
 import GHC.Types.SrcLoc
 import Ormolu.Printer.Combinators
@@ -33,12 +31,12 @@
   breakpoint
   inci
     . switchLayout
-      [ getLoc (fd_name fd),
-        (getLoc . hsib_body . fd_sig_ty) fd
+      [ getLocA (fd_name fd),
+        (getLocA . fd_sig_ty) fd
       ]
     $ do
       p_rdrName (fd_name fd)
-      p_typeAscription (HsWC NoExtField (fd_sig_ty fd))
+      p_typeAscription (fd_sig_ty fd)
 
 -- | Printer for 'ForeignImport'.
 --
diff --git a/src/Ormolu/Printer/Meat/Declaration/Instance.hs b/src/Ormolu/Printer/Meat/Declaration/Instance.hs
--- a/src/Ormolu/Printer/Meat/Declaration/Instance.hs
+++ b/src/Ormolu/Printer/Meat/Declaration/Instance.hs
@@ -16,9 +16,7 @@
 import Data.Foldable
 import Data.Function (on)
 import Data.List (sortBy)
-import GHC.Hs.Decls
-import GHC.Hs.Extension
-import GHC.Hs.Type
+import GHC.Hs
 import GHC.Types.Basic
 import GHC.Types.SrcLoc
 import Ormolu.Printer.Combinators
@@ -30,7 +28,7 @@
 
 p_standaloneDerivDecl :: DerivDecl GhcPs -> R ()
 p_standaloneDerivDecl DerivDecl {..} = do
-  let typesAfterInstance = located (hsib_body (hswc_body deriv_type)) p_hsType
+  let typesAfterInstance = located (hswc_body deriv_type) p_hsSigType
       instTypes toIndent = inci $ do
         txt "instance"
         breakpoint
@@ -42,47 +40,46 @@
     Nothing ->
       instTypes False
     Just (L _ a) -> case a of
-      StockStrategy -> do
+      StockStrategy _ -> do
         txt "stock "
         instTypes False
-      AnyclassStrategy -> do
+      AnyclassStrategy _ -> do
         txt "anyclass "
         instTypes False
-      NewtypeStrategy -> do
+      NewtypeStrategy _ -> do
         txt "newtype "
         instTypes False
-      ViaStrategy HsIB {..} -> do
+      ViaStrategy (XViaStrategyPs _ sigTy) -> do
         txt "via"
         breakpoint
-        inci (located hsib_body p_hsType)
+        inci (located sigTy p_hsSigType)
         breakpoint
         instTypes True
 
 p_clsInstDecl :: ClsInstDecl GhcPs -> R ()
 p_clsInstDecl ClsInstDecl {..} = do
   txt "instance"
-  let HsIB {..} = cid_poly_ty
   -- GHC's AST does not necessarily store each kind of element in source
   -- location order. This happens because different declarations are stored in
   -- different lists. Consequently, to get all the declarations in proper
   -- order, they need to be manually sorted.
-  let sigs = (getLoc &&& fmap (SigD NoExtField)) <$> cid_sigs
-      vals = (getLoc &&& fmap (ValD NoExtField)) <$> toList cid_binds
+  let sigs = (getLocA &&& fmap (SigD NoExtField)) <$> cid_sigs
+      vals = (getLocA &&& fmap (ValD NoExtField)) <$> toList cid_binds
       tyFamInsts =
-        ( getLoc &&& fmap (InstD NoExtField . TyFamInstD NoExtField)
+        ( getLocA &&& fmap (InstD NoExtField . TyFamInstD NoExtField)
         )
           <$> cid_tyfam_insts
       dataFamInsts =
-        ( getLoc &&& fmap (InstD NoExtField . DataFamInstD NoExtField)
+        ( getLocA &&& fmap (InstD NoExtField . DataFamInstD EpAnnNotUsed)
         )
           <$> cid_datafam_insts
       allDecls =
         snd <$> sortBy (leftmost_smallest `on` fst) (sigs <> vals <> tyFamInsts <> dataFamInsts)
-  located hsib_body $ \x -> do
+  located cid_poly_ty $ \sigTy -> do
     breakpoint
     inci $ do
       match_overlap_mode cid_overlap_mode breakpoint
-      p_hsType x
+      p_hsSigType sigTy
       unless (null allDecls) $ do
         breakpoint
         txt "where"
@@ -100,10 +97,10 @@
   inci (p_tyFamInstEqn tfid_eqn)
 
 p_dataFamInstDecl :: FamilyStyle -> DataFamInstDecl GhcPs -> R ()
-p_dataFamInstDecl style (DataFamInstDecl {dfid_eqn = HsIB {hsib_body = FamEqn {..}}}) =
+p_dataFamInstDecl style (DataFamInstDecl {dfid_eqn = FamEqn {..}}) =
   p_dataDecl style feqn_tycon feqn_pats feqn_fixity feqn_rhs
 
-match_overlap_mode :: Maybe (Located OverlapMode) -> R () -> R ()
+match_overlap_mode :: Maybe (LocatedP OverlapMode) -> R () -> R ()
 match_overlap_mode overlap_mode layoutStrategy =
   case unLoc <$> overlap_mode of
     Just Overlappable {} -> do
diff --git a/src/Ormolu/Printer/Meat/Declaration/RoleAnnotation.hs b/src/Ormolu/Printer/Meat/Declaration/RoleAnnotation.hs
--- a/src/Ormolu/Printer/Meat/Declaration/RoleAnnotation.hs
+++ b/src/Ormolu/Printer/Meat/Declaration/RoleAnnotation.hs
@@ -9,17 +9,16 @@
 where
 
 import GHC.Core.Coercion.Axiom
-import GHC.Hs.Decls
-import GHC.Hs.Extension
+import GHC.Hs hiding (anns)
 import GHC.Types.Name.Reader
 import GHC.Types.SrcLoc
 import Ormolu.Printer.Combinators
 import Ormolu.Printer.Meat.Common
 
 p_roleAnnot :: RoleAnnotDecl GhcPs -> R ()
-p_roleAnnot (RoleAnnotDecl NoExtField l_name anns) = p_roleAnnot' l_name anns
+p_roleAnnot (RoleAnnotDecl _ l_name anns) = p_roleAnnot' l_name anns
 
-p_roleAnnot' :: Located RdrName -> [Located (Maybe Role)] -> R ()
+p_roleAnnot' :: LocatedN RdrName -> [Located (Maybe Role)] -> R ()
 p_roleAnnot' l_name anns = do
   txt "type role"
   breakpoint
diff --git a/src/Ormolu/Printer/Meat/Declaration/Rule.hs b/src/Ormolu/Printer/Meat/Declaration/Rule.hs
--- a/src/Ormolu/Printer/Meat/Declaration/Rule.hs
+++ b/src/Ormolu/Printer/Meat/Declaration/Rule.hs
@@ -8,11 +8,9 @@
 where
 
 import Control.Monad (unless)
-import GHC.Hs.Decls
-import GHC.Hs.Extension
-import GHC.Hs.Lit
-import GHC.Hs.Type
+import GHC.Hs
 import GHC.Types.Basic
+import GHC.Types.SourceText
 import Ormolu.Printer.Combinators
 import Ormolu.Printer.Meat.Common
 import Ormolu.Printer.Meat.Declaration.Signature
@@ -20,11 +18,11 @@
 import Ormolu.Printer.Meat.Type
 
 p_ruleDecls :: RuleDecls GhcPs -> R ()
-p_ruleDecls (HsRules NoExtField _ xs) =
+p_ruleDecls (HsRules _ _ xs) =
   pragma "RULES" $ sep breakpoint (sitcc . located' p_ruleDecl) xs
 
 p_ruleDecl :: RuleDecl GhcPs -> R ()
-p_ruleDecl (HsRule NoExtField ruleName activation tyvars ruleBndrs lhs rhs) = do
+p_ruleDecl (HsRule _ ruleName activation tyvars ruleBndrs lhs rhs) = do
   located ruleName p_ruleName
   space
   p_activation activation
@@ -38,7 +36,7 @@
   -- in the input or no forall at all. We do not want to add redundant
   -- foralls, so let's just skip the empty ones.
   unless (null ruleBndrs) $
-    p_forallBndrs ForAllInvis p_ruleBndr ruleBndrs
+    p_forallBndrs ForAllInvis p_ruleBndr (reLocA <$> ruleBndrs)
   breakpoint
   inci $ do
     located lhs p_hsExpr
@@ -53,7 +51,7 @@
 
 p_ruleBndr :: RuleBndr GhcPs -> R ()
 p_ruleBndr = \case
-  RuleBndr NoExtField x -> p_rdrName x
-  RuleBndrSig NoExtField x HsPS {..} -> parens N . sitcc $ do
+  RuleBndr _ x -> p_rdrName x
+  RuleBndrSig _ x HsPS {..} -> parens N . sitcc $ do
     p_rdrName x
-    p_typeAscription (HsWC NoExtField (HsIB NoExtField hsps_body))
+    p_typeAscription (lhsTypeToSigType hsps_body)
diff --git a/src/Ormolu/Printer/Meat/Declaration/Signature.hs b/src/Ormolu/Printer/Meat/Declaration/Signature.hs
--- a/src/Ormolu/Printer/Meat/Declaration/Signature.hs
+++ b/src/Ormolu/Printer/Meat/Declaration/Signature.hs
@@ -13,12 +13,11 @@
 
 import Control.Monad
 import GHC.Data.BooleanFormula
-import GHC.Hs.Binds
-import GHC.Hs.Decls
-import GHC.Hs.Extension
-import GHC.Hs.Type
+import GHC.Hs
 import GHC.Types.Basic
+import GHC.Types.Fixity
 import GHC.Types.Name.Reader
+import GHC.Types.SourceText
 import GHC.Types.SrcLoc
 import Ormolu.Printer.Combinators
 import Ormolu.Printer.Meat.Common
@@ -27,59 +26,54 @@
 
 p_sigDecl :: Sig GhcPs -> R ()
 p_sigDecl = \case
-  TypeSig NoExtField names hswc -> p_typeSig True names hswc
-  PatSynSig NoExtField names hsib -> p_patSynSig names hsib
-  ClassOpSig NoExtField def names hsib -> p_classOpSig def names hsib
-  FixSig NoExtField sig -> p_fixSig sig
-  InlineSig NoExtField name inlinePragma -> p_inlineSig name inlinePragma
-  SpecSig NoExtField name ts inlinePragma -> p_specSig name ts inlinePragma
-  SpecInstSig NoExtField _ hsib -> p_specInstSig hsib
-  MinimalSig NoExtField _ booleanFormula -> p_minimalSig booleanFormula
-  CompleteMatchSig NoExtField _sourceText cs ty -> p_completeSig cs ty
-  SCCFunSig NoExtField _ name literal -> p_sccSig name literal
+  TypeSig _ names hswc -> p_typeSig True names (hswc_body hswc)
+  PatSynSig _ names sigType -> p_patSynSig names sigType
+  ClassOpSig _ def names sigType -> p_classOpSig def names sigType
+  FixSig _ sig -> p_fixSig sig
+  InlineSig _ name inlinePragma -> p_inlineSig name inlinePragma
+  SpecSig _ name ts inlinePragma -> p_specSig name ts inlinePragma
+  SpecInstSig _ _ sigType -> p_specInstSig sigType
+  MinimalSig _ _ booleanFormula -> p_minimalSig booleanFormula
+  CompleteMatchSig _ _sourceText cs ty -> p_completeSig cs ty
+  SCCFunSig _ _ name literal -> p_sccSig name literal
   _ -> notImplemented "certain types of signature declarations"
 
 p_typeSig ::
   -- | Should the tail of the names be indented
   Bool ->
   -- | Names (before @::@)
-  [Located RdrName] ->
+  [LocatedN RdrName] ->
   -- | Type
-  LHsSigWcType GhcPs ->
+  LHsSigType GhcPs ->
   R ()
 p_typeSig _ [] _ = return () -- should not happen though
-p_typeSig indentTail (n : ns) hswc = do
+p_typeSig indentTail (n : ns) sigType = do
   p_rdrName n
   if null ns
-    then p_typeAscription hswc
+    then p_typeAscription sigType
     else inciIf indentTail $ do
       commaDel
       sep commaDel p_rdrName ns
-      p_typeAscription hswc
+      p_typeAscription sigType
 
 p_typeAscription ::
-  LHsSigWcType GhcPs ->
+  LHsSigType GhcPs ->
   R ()
-p_typeAscription HsWC {..} = inci $ do
+p_typeAscription sigType = inci $ do
   space
   txt "::"
-  let t = hsib_body hswc_body
-  if hasDocStrings (unLoc t)
+  if hasDocStrings (unLoc . sig_body . unLoc $ sigType)
     then newline
     else breakpoint
-  located t p_hsType
+  located sigType p_hsSigType
 
 p_patSynSig ::
-  [Located RdrName] ->
-  HsImplicitBndrs GhcPs (LHsType GhcPs) ->
+  [LocatedN RdrName] ->
+  LHsSigType GhcPs ->
   R ()
-p_patSynSig names hsib = do
+p_patSynSig names sigType = do
   txt "pattern"
-  let body =
-        p_typeSig
-          False
-          names
-          HsWC {hswc_ext = NoExtField, hswc_body = hsib}
+  let body = p_typeSig False names sigType
   if length names > 1
     then breakpoint >> inci body
     else space >> body
@@ -88,13 +82,13 @@
   -- | Whether this is a \"default\" signature
   Bool ->
   -- | Names (before @::@)
-  [Located RdrName] ->
+  [LocatedN RdrName] ->
   -- | Type
-  HsImplicitBndrs GhcPs (LHsType GhcPs) ->
+  LHsSigType GhcPs ->
   R ()
-p_classOpSig def names hsib = do
+p_classOpSig def names sigType = do
   when def (txt "default" >> space)
-  p_typeSig True names HsWC {hswc_ext = NoExtField, hswc_body = hsib}
+  p_typeSig True names sigType
 
 p_fixSig ::
   FixitySig GhcPs ->
@@ -112,7 +106,7 @@
 
 p_inlineSig ::
   -- | Name
-  Located RdrName ->
+  LocatedN RdrName ->
   -- | Inline pragma specification
   InlinePragma ->
   R ()
@@ -123,13 +117,13 @@
     ConLike -> txt "CONLIKE"
     FunLike -> return ()
   space
-  p_activation inl_act
+  when (inl_act /= NeverActive) $ p_activation inl_act
   space
   p_rdrName name
 
 p_specSig ::
   -- | Name
-  Located RdrName ->
+  LocatedN RdrName ->
   -- | The types to specialize to
   [LHsSigType GhcPs] ->
   -- | For specialize inline
@@ -146,18 +140,18 @@
   space
   txt "::"
   breakpoint
-  inci $ sep commaDel (located' p_hsType . hsib_body) ts
+  inci $ sep commaDel (located' p_hsSigType) ts
 
 p_inlineSpec :: InlineSpec -> R ()
 p_inlineSpec = \case
   Inline -> txt "INLINE"
   Inlinable -> txt "INLINEABLE"
   NoInline -> txt "NOINLINE"
-  NoUserInline -> return ()
+  NoUserInlinePrag -> return ()
 
 p_activation :: Activation -> R ()
 p_activation = \case
-  NeverActive -> return ()
+  NeverActive -> txt "[~]"
   AlwaysActive -> return ()
   ActiveBefore _ n -> do
     txt "[~"
@@ -170,13 +164,13 @@
   FinalActive -> notImplemented "FinalActive" -- NOTE(amesgen) is this unreachable or just not implemented?
 
 p_specInstSig :: LHsSigType GhcPs -> R ()
-p_specInstSig hsib =
+p_specInstSig sigType =
   pragma "SPECIALIZE instance" . inci $
-    located (hsib_body hsib) p_hsType
+    located sigType p_hsSigType
 
 p_minimalSig ::
   -- | Boolean formula
-  LBooleanFormula (Located RdrName) ->
+  LBooleanFormula (LocatedN RdrName) ->
   R ()
 p_minimalSig =
   located' $ \booleanFormula ->
@@ -184,7 +178,7 @@
 
 p_booleanFormula ::
   -- | Boolean formula
-  BooleanFormula (Located RdrName) ->
+  BooleanFormula (LocatedN RdrName) ->
   R ()
 p_booleanFormula = \case
   Var name -> p_rdrName name
@@ -204,9 +198,9 @@
 
 p_completeSig ::
   -- | Constructors\/patterns
-  Located [Located RdrName] ->
+  Located [LocatedN RdrName] ->
   -- | Type
-  Maybe (Located RdrName) ->
+  Maybe (LocatedN RdrName) ->
   R ()
 p_completeSig cs' mty =
   located cs' $ \cs ->
@@ -218,7 +212,7 @@
         breakpoint
         inci (p_rdrName ty)
 
-p_sccSig :: Located (IdP GhcPs) -> Maybe (Located StringLiteral) -> R ()
+p_sccSig :: LocatedN RdrName -> Maybe (Located StringLiteral) -> R ()
 p_sccSig loc literal = pragma "SCC" . inci $ do
   p_rdrName loc
   forM_ literal $ \x -> do
@@ -226,7 +220,7 @@
     atom x
 
 p_standaloneKindSig :: StandaloneKindSig GhcPs -> R ()
-p_standaloneKindSig (StandaloneKindSig NoExtField name (HsIB NoExtField sig)) = do
+p_standaloneKindSig (StandaloneKindSig _ name sigTy) = do
   txt "type"
   inci $ do
     space
@@ -234,4 +228,4 @@
     space
     txt "::"
     breakpoint
-    located sig p_hsType
+    located sigTy p_hsSigType
diff --git a/src/Ormolu/Printer/Meat/Declaration/Splice.hs b/src/Ormolu/Printer/Meat/Declaration/Splice.hs
--- a/src/Ormolu/Printer/Meat/Declaration/Splice.hs
+++ b/src/Ormolu/Printer/Meat/Declaration/Splice.hs
@@ -5,8 +5,7 @@
   )
 where
 
-import GHC.Hs.Decls
-import GHC.Hs.Extension
+import GHC.Hs
 import Ormolu.Printer.Combinators
 import Ormolu.Printer.Meat.Declaration.Value (p_hsSplice)
 
diff --git a/src/Ormolu/Printer/Meat/Declaration/Type.hs b/src/Ormolu/Printer/Meat/Declaration/Type.hs
--- a/src/Ormolu/Printer/Meat/Declaration/Type.hs
+++ b/src/Ormolu/Printer/Meat/Declaration/Type.hs
@@ -9,7 +9,8 @@
 
 import GHC.Hs.Extension
 import GHC.Hs.Type
-import GHC.Types.Basic
+import GHC.Parser.Annotation
+import GHC.Types.Fixity
 import GHC.Types.Name.Reader
 import GHC.Types.SrcLoc
 import Ormolu.Printer.Combinators
@@ -18,7 +19,7 @@
 
 p_synDecl ::
   -- | Type constructor
-  Located RdrName ->
+  LocatedN RdrName ->
   -- | Fixity
   LexicalFixity ->
   -- | Type variables
@@ -29,7 +30,7 @@
 p_synDecl name fixity HsQTvs {..} t = do
   txt "type"
   space
-  switchLayout (getLoc name : map getLoc hsq_explicit) $
+  switchLayout (getLocA name : map getLocA hsq_explicit) $
     p_infixDefHelper
       (case fixity of Infix -> True; _ -> False)
       True
diff --git a/src/Ormolu/Printer/Meat/Declaration/TypeFamily.hs b/src/Ormolu/Printer/Meat/Declaration/TypeFamily.hs
--- a/src/Ormolu/Printer/Meat/Declaration/TypeFamily.hs
+++ b/src/Ormolu/Printer/Meat/Declaration/TypeFamily.hs
@@ -11,10 +11,8 @@
 
 import Control.Monad
 import Data.Maybe (isNothing)
-import GHC.Hs.Decls
-import GHC.Hs.Extension
-import GHC.Hs.Type
-import GHC.Types.Basic
+import GHC.Hs
+import GHC.Types.Fixity
 import GHC.Types.SrcLoc
 import Ormolu.Printer.Combinators
 import Ormolu.Printer.Meat.Common
@@ -29,9 +27,11 @@
   txt $ case style of
     Associated -> mempty
     Free -> " family"
-  breakpoint
-  inci $ do
-    switchLayout (getLoc fdLName : (getLoc <$> hsq_explicit)) $
+  let headerSpns = getLocA fdLName : (getLocA <$> hsq_explicit)
+      headerAndSigSpns = getLoc fdResultSig : headerSpns
+  inci . switchLayout headerAndSigSpns $ do
+    breakpoint
+    switchLayout headerSpns $ do
       p_infixDefHelper
         (isInfix fdFixity)
         True
@@ -46,7 +46,7 @@
   case mmeqs of
     Nothing -> return ()
     Just meqs -> do
-      inci $ do
+      inci . switchLayout headerAndSigSpns $ do
         breakpoint
         txt "where"
       case meqs of
@@ -72,7 +72,7 @@
     located bndr p_hsTyVarBndr
 
 p_injectivityAnn :: InjectivityAnn GhcPs -> R ()
-p_injectivityAnn (InjectivityAnn a bs) = do
+p_injectivityAnn (InjectivityAnn _ a bs) = do
   txt "|"
   space
   p_rdrName a
@@ -82,14 +82,17 @@
   sep space p_rdrName bs
 
 p_tyFamInstEqn :: TyFamInstEqn GhcPs -> R ()
-p_tyFamInstEqn HsIB {hsib_body = FamEqn {..}} = do
+p_tyFamInstEqn FamEqn {..} = do
   case feqn_bndrs of
-    Nothing -> return ()
-    Just bndrs -> do
+    HsOuterImplicit NoExtField -> return ()
+    HsOuterExplicit _ bndrs -> do
       p_forallBndrs ForAllInvis p_hsTyVarBndr bndrs
       breakpoint
-  inciIf (not $ null feqn_bndrs) $ do
-    let famLhsSpn = getLoc feqn_tycon : fmap lhsTypeArgSrcSpan feqn_pats
+  let atLeastOneBndr = case feqn_bndrs of
+        HsOuterImplicit NoExtField -> False
+        HsOuterExplicit _ bndrs -> not $ null bndrs
+  inciIf atLeastOneBndr $ do
+    let famLhsSpn = getLocA feqn_tycon : fmap lhsTypeArgSrcSpan feqn_pats
     switchLayout famLhsSpn $
       p_infixDefHelper
         (isInfix feqn_fixity)
diff --git a/src/Ormolu/Printer/Meat/Declaration/Value.hs b/src/Ormolu/Printer/Meat/Declaration/Value.hs
--- a/src/Ormolu/Printer/Meat/Declaration/Value.hs
+++ b/src/Ormolu/Printer/Meat/Declaration/Value.hs
@@ -1,9 +1,11 @@
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE MultiWayIf #-}
+{-# LANGUAGE NamedFieldPuns #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE PatternSynonyms #-}
 {-# LANGUAGE RecordWildCards #-}
 {-# LANGUAGE TypeApplications #-}
+{-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE ViewPatterns #-}
 
 module Ormolu.Printer.Meat.Declaration.Value
@@ -17,7 +19,7 @@
 
 import Control.Monad
 import Data.Bool (bool)
-import Data.Char (isPunctuation, isSymbol)
+import Data.Coerce (coerce)
 import Data.Data hiding (Infix, Prefix)
 import Data.Function (on)
 import Data.Functor ((<&>))
@@ -25,26 +27,24 @@
 import Data.List (intersperse, sortBy)
 import Data.List.NonEmpty (NonEmpty (..), (<|))
 import qualified Data.List.NonEmpty as NE
-import Data.Maybe (isJust)
+import Data.Maybe
 import Data.Text (Text)
 import qualified Data.Text as Text
+import Data.Void
 import GHC.Data.Bag (bagToList)
-import GHC.Hs.Binds
-import GHC.Hs.Expr
-import GHC.Hs.Extension
-import GHC.Hs.Lit
-import GHC.Hs.Pat
-import GHC.Hs.Type
+import GHC.Data.FastString (FastString, lengthFS)
+import GHC.Hs
 import GHC.LanguageExtensions.Type (Extension (NegativeLiterals))
-import GHC.Parser.Annotation
 import GHC.Parser.CharClass (is_space)
 import GHC.Types.Basic
+import GHC.Types.Fixity
 import GHC.Types.Name.Occurrence (occNameString)
 import GHC.Types.Name.Reader
+import GHC.Types.SourceText
 import GHC.Types.SrcLoc
 import Ormolu.Config
 import Ormolu.Printer.Combinators
-import Ormolu.Printer.Internal
+import Ormolu.Printer.Internal (inciBy, sitccIfTrailing)
 import Ormolu.Printer.Meat.Common
 import {-# SOURCE #-} Ormolu.Printer.Meat.Declaration
 import Ormolu.Printer.Meat.Declaration.Signature
@@ -54,7 +54,7 @@
 
 -- | Style of a group of equations.
 data MatchGroupStyle
-  = Function (Located RdrName)
+  = Function (LocatedN RdrName)
   | PatternBind
   | Case
   | Lambda
@@ -80,14 +80,14 @@
 
 p_valDecl :: HsBindLR GhcPs GhcPs -> R ()
 p_valDecl = \case
-  FunBind NoExtField funId funMatches _ -> p_funBind funId funMatches
-  PatBind NoExtField pat grhss _ -> p_match PatternBind False NoSrcStrict [pat] grhss
+  FunBind _ funId funMatches _ -> p_funBind funId funMatches
+  PatBind _ pat grhss _ -> p_match PatternBind False NoSrcStrict [pat] grhss
   VarBind {} -> notImplemented "VarBinds" -- introduced by the type checker
   AbsBinds {} -> notImplemented "AbsBinds" -- introduced by the type checker
-  PatSynBind NoExtField psb -> p_patSynBind psb
+  PatSynBind _ psb -> p_patSynBind psb
 
 p_funBind ::
-  Located RdrName ->
+  LocatedN RdrName ->
   MatchGroup GhcPs (LHsExpr GhcPs) ->
   R ()
 p_funBind name = p_matchGroup (Function name)
@@ -99,7 +99,9 @@
 p_matchGroup = p_matchGroup' exprPlacement p_hsExpr
 
 p_matchGroup' ::
-  Data body =>
+  ( Anno (GRHS GhcPs (LocatedA body)) ~ SrcSpan,
+    Anno (Match GhcPs (LocatedA body)) ~ SrcSpanAnnA
+  ) =>
   -- | How to get body placement
   (body -> Placement) ->
   -- | How to print body
@@ -107,7 +109,7 @@
   -- | Style of this group of equations
   MatchGroupStyle ->
   -- | Match group
-  MatchGroup GhcPs (Located body) ->
+  MatchGroup GhcPs (LocatedA body) ->
   R ()
 p_matchGroup' placer render style mg@MG {..} = do
   let ob = case style of
@@ -166,7 +168,7 @@
 p_match = p_match' exprPlacement p_hsExpr
 
 p_match' ::
-  Data body =>
+  (Anno (GRHS GhcPs (LocatedA body)) ~ SrcSpan) =>
   -- | How to get body placement
   (body -> Placement) ->
   -- | How to print body
@@ -180,7 +182,7 @@
   -- | Argument patterns
   [LPat GhcPs] ->
   -- | Equations
-  GRHSs GhcPs (Located body) ->
+  GRHSs GhcPs (LocatedA body) ->
   R ()
 p_match' placer render style isInfix strictness m_pats GRHSs {..} = do
   -- Normally, since patterns may be placed in a multi-line layout, it is
@@ -201,9 +203,9 @@
         _ -> return ()
     Just ne_pats -> do
       let combinedSpans = case style of
-            Function name -> combineSrcSpans (getLoc name) patSpans
+            Function name -> combineSrcSpans (getLocA name) patSpans
             _ -> patSpans
-          patSpans = combineSrcSpans' (getLoc <$> ne_pats)
+          patSpans = combineSrcSpans' (getLocA <$> ne_pats)
           indentBody = not (isOneLineSpan combinedSpans)
       switchLayout [combinedSpans] $ do
         let stdCase = sep breakpoint (located' p_pat) m_pats
@@ -231,9 +233,9 @@
       -- about putting certain constructions in hanging positions.
       endOfPats = case NE.nonEmpty m_pats of
         Nothing -> case style of
-          Function name -> Just (getLoc name)
+          Function name -> Just (getLocA name)
           _ -> Nothing
-        Just pats -> (Just . getLoc . NE.last) pats
+        Just pats -> (Just . getLocA . NE.last) pats
       isCase = \case
         Case -> True
         LambdaCase -> True
@@ -249,25 +251,32 @@
           endOfPats
       placement =
         case endOfPats of
-          Nothing -> blockPlacement placer grhssGRHSs
-          Just spn ->
-            if onTheSameLine spn grhssSpan
-              then blockPlacement placer grhssGRHSs
-              else Normal
+          Just spn
+            | any guardNeedsLineBreak grhssGRHSs
+                || not (onTheSameLine spn grhssSpan) ->
+                Normal
+          _ -> blockPlacement placer grhssGRHSs
+      guardNeedsLineBreak :: Located (GRHS GhcPs body) -> Bool
+      guardNeedsLineBreak (L _ (GRHS _ guardLStmts _)) = case guardLStmts of
+        [] -> False
+        [g] -> not . isOneLineSpan . getLocA $ g
+        _ -> True
       p_body = do
         let groupStyle =
               if isCase style && hasGuards
                 then RightArrow
                 else EqualSign
-        sep newline (located' (p_grhs' placer render groupStyle)) grhssGRHSs
+        sep
+          breakpoint
+          (located' (p_grhs' placement placer render groupStyle) . reLocA)
+          grhssGRHSs
       p_where = do
-        let whereIsEmpty = eqEmptyLocalBinds (unLoc grhssLocalBinds)
-        unless (eqEmptyLocalBinds (unLoc grhssLocalBinds)) $ do
+        unless (eqEmptyLocalBinds grhssLocalBinds) $ do
           breakpoint
           indentWhere <- getPrinterOpt poIndentWheres
           bool (inciByFrac $ -2) id indentWhere $ txt "where"
-          unless whereIsEmpty breakpoint
-          inciIf indentWhere $ located grhssLocalBinds p_hsLocalBinds
+          breakpoint
+          inciIf indentWhere $ p_hsLocalBinds grhssLocalBinds
   inciIf indentBody $ do
     unless (length grhssGRHSs > 1) $
       case style of
@@ -281,41 +290,47 @@
     inci p_where
 
 p_grhs :: GroupStyle -> GRHS GhcPs (LHsExpr GhcPs) -> R ()
-p_grhs = p_grhs' exprPlacement p_hsExpr
+p_grhs = p_grhs' Normal exprPlacement p_hsExpr
 
 p_grhs' ::
-  Data body =>
+  -- | Placement of the parent RHS construct
+  Placement ->
   -- | How to get body placement
   (body -> Placement) ->
   -- | How to print body
   (body -> R ()) ->
   GroupStyle ->
-  GRHS GhcPs (Located body) ->
+  GRHS GhcPs (LocatedA body) ->
   R ()
-p_grhs' placer render style (GRHS NoExtField guards body) =
+p_grhs' parentPlacement placer render style (GRHS _ guards body) =
   case guards of
     [] -> p_body
     xs -> do
       txt "|"
       space
-      sitcc (sep commaDel (sitcc . located' p_stmt) xs)
+      sitccIfTrailing (sep commaDel (sitcc . located' p_stmt) xs)
       space
       inci $ case style of
         EqualSign -> equals
         RightArrow -> txt "->"
-      placeHanging placement p_body
+      -- If we have a sequence of guards and it is placed in the normal way,
+      -- then we indent one level more for readability. Otherwise (all
+      -- guards are on the same line) we do not need to indent, as it would
+      -- look like double indentation without a good reason.
+      indent <- getPrinterOpt poIndentation
+      inciIf (indent <= 2 && parentPlacement == Normal) (placeHanging placement p_body)
   where
     placement =
       case endOfGuards of
         Nothing -> placer (unLoc body)
         Just spn ->
-          if onTheSameLine spn (getLoc body)
+          if onTheSameLine spn (getLocA body)
             then placer (unLoc body)
             else Normal
     endOfGuards =
       case NE.nonEmpty guards of
         Nothing -> Nothing
-        Just gs -> (Just . getLoc . NE.last) gs
+        Just gs -> (Just . getLocA . NE.last) gs
     p_body = located body render
 
 p_hsCmd :: HsCmd GhcPs -> R ()
@@ -323,7 +338,7 @@
 
 p_hsCmd' :: BracketStyle -> HsCmd GhcPs -> R ()
 p_hsCmd' s = \case
-  HsCmdArrApp NoExtField body input arrType rightToLeft -> do
+  HsCmdArrApp _ body input arrType rightToLeft -> do
     let (l, r) = if rightToLeft then (body, input) else (input, body)
     located l p_hsExpr
     breakpoint
@@ -335,35 +350,35 @@
         (HsHigherOrderApp, False) -> txt ">>-"
       placeHanging (exprPlacement (unLoc input)) $
         located r p_hsExpr
-  HsCmdArrForm NoExtField form Prefix _ cmds -> banana s $ do
+  HsCmdArrForm _ form Prefix _ cmds -> banana s $ do
     located form p_hsExpr
     unless (null cmds) $ do
       breakpoint
       inci (sequence_ (intersperse breakpoint (located' p_hsCmdTop <$> cmds)))
-  HsCmdArrForm NoExtField form Infix _ [left, right] ->
+  HsCmdArrForm _ form Infix _ [left, right] ->
     let opTree = OpBranch (cmdOpTree left) form (cmdOpTree right)
      in p_cmdOpTree (reassociateOpTree getOpName opTree)
-  HsCmdArrForm NoExtField _ Infix _ _ -> notImplemented "HsCmdArrForm"
-  HsCmdApp NoExtField cmd expr -> do
+  HsCmdArrForm _ _ Infix _ _ -> notImplemented "HsCmdArrForm"
+  HsCmdApp _ cmd expr -> do
     located cmd (p_hsCmd' s)
     space
     located expr p_hsExpr
-  HsCmdLam NoExtField mgroup -> p_matchGroup' cmdPlacement p_hsCmd Lambda mgroup
-  HsCmdPar NoExtField c -> parens N $ sitcc $ located c p_hsCmd
-  HsCmdCase NoExtField e mgroup ->
+  HsCmdLam _ mgroup -> p_matchGroup' cmdPlacement p_hsCmd Lambda mgroup
+  HsCmdPar _ c -> parens N $ sitcc $ located c p_hsCmd
+  HsCmdCase _ e mgroup ->
     p_case cmdPlacement p_hsCmd e mgroup
-  HsCmdLamCase NoExtField mgroup ->
+  HsCmdLamCase _ mgroup ->
     p_lamcase cmdPlacement p_hsCmd mgroup
-  HsCmdIf NoExtField _ if' then' else' ->
+  HsCmdIf _ _ if' then' else' ->
     p_if cmdPlacement p_hsCmd if' then' else'
-  HsCmdLet NoExtField localBinds c ->
+  HsCmdLet _ localBinds c ->
     p_let p_hsCmd localBinds c
-  HsCmdDo NoExtField es -> do
+  HsCmdDo _ es -> do
     txt "do"
     p_stmts cmdPlacement (p_hsCmd' S) es
 
 p_hsCmdTop :: HsCmdTop GhcPs -> R ()
-p_hsCmdTop (HsCmdTop NoExtField cmd) = located cmd p_hsCmd
+p_hsCmdTop (HsCmdTop _ cmd) = located cmd p_hsCmd
 
 -- | Render an expression preserving blank lines between such consecutive
 -- expressions found in the original source code.
@@ -371,10 +386,10 @@
   -- | Rendering function
   (a -> R ()) ->
   -- | Entity to render
-  Located a ->
+  LocatedAn ann a ->
   R ()
 withSpacing f l = located l $ \x -> do
-  case getLoc l of
+  case getLocA l of
     UnhelpfulSpan _ -> f x
     RealSrcSpan currentSpn _ -> do
       getSpanMark >>= \case
@@ -398,32 +413,34 @@
 p_stmt = p_stmt' exprPlacement p_hsExpr
 
 p_stmt' ::
-  Data body =>
+  ( Anno (Stmt GhcPs (LocatedA body)) ~ SrcSpanAnnA,
+    Anno [LocatedA (Stmt GhcPs (LocatedA body))] ~ SrcSpanAnnL
+  ) =>
   -- | Placer
   (body -> Placement) ->
   -- | Render
   (body -> R ()) ->
   -- | Statement to render
-  Stmt GhcPs (Located body) ->
+  Stmt GhcPs (LocatedA body) ->
   R ()
 p_stmt' placer render = \case
-  LastStmt NoExtField body _ _ -> located body render
-  BindStmt NoExtField p f@(L l x) -> do
+  LastStmt _ body _ _ -> located body render
+  BindStmt _ p f@(getLocA -> l) -> do
     located p p_pat
     space
     txt "<-"
-    let loc = getLoc p
+    let loc = getLocA p
         placement
-          | isOneLineSpan (mkSrcSpan (srcSpanEnd loc) (srcSpanStart l)) = placer x
+          | isOneLineSpan (mkSrcSpan (srcSpanEnd loc) (srcSpanStart l)) = placer (unLoc f)
           | otherwise = Normal
     switchLayout [loc, l] $
       placeHanging placement (located f render)
   ApplicativeStmt {} -> notImplemented "ApplicativeStmt" -- generated by renamer
-  BodyStmt NoExtField body _ _ -> located body render
-  LetStmt NoExtField binds -> do
+  BodyStmt _ body _ _ -> located body render
+  LetStmt _ binds -> do
     txt "let"
     space
-    sitcc $ located binds p_hsLocalBinds
+    sitcc $ p_hsLocalBinds binds
   ParStmt {} ->
     -- 'ParStmt' should always be eliminated in 'gatherStmt' already, such
     -- that it never occurs in 'p_stmt''. Consequently, handling it here
@@ -461,16 +478,18 @@
   RecStmt {..} -> do
     txt "rec"
     space
-    sitcc $ sepSemi (withSpacing (p_stmt' placer render)) recS_stmts
+    sitcc . located recS_stmts $ sepSemi (withSpacing (p_stmt' placer render))
 
 p_stmts ::
-  Data body =>
+  ( Anno (Stmt GhcPs (LocatedA body)) ~ SrcSpanAnnA,
+    Anno [LocatedA (Stmt GhcPs (LocatedA body))] ~ SrcSpanAnnL
+  ) =>
   -- | Placer
   (body -> Placement) ->
   -- | Render
   (body -> R ()) ->
   -- | Statements to render
-  Located [Located (Stmt GhcPs (Located body))] ->
+  LocatedL [LocatedA (Stmt GhcPs (LocatedA body))] ->
   R ()
 p_stmts placer render es = do
   breakpoint
@@ -480,7 +499,7 @@
       (ub . withSpacing (p_stmt' placer render))
 
 gatherStmt :: ExprLStmt GhcPs -> [[ExprLStmt GhcPs]]
-gatherStmt (L _ (ParStmt NoExtField block _ _)) =
+gatherStmt (L _ (ParStmt _ block _ _)) =
   foldr ((<>) . gatherStmtBlock) [] block
 gatherStmt (L s stmt@TransStmt {..}) =
   foldr liftAppend [] ((gatherStmt <$> trS_stmts) <> pure [[L s stmt]])
@@ -490,9 +509,9 @@
 gatherStmtBlock (ParStmtBlock _ stmts _ _) =
   foldr (liftAppend . gatherStmt) [] stmts
 
-p_hsLocalBinds :: HsLocalBindsLR GhcPs GhcPs -> R ()
+p_hsLocalBinds :: HsLocalBinds GhcPs -> R ()
 p_hsLocalBinds = \case
-  HsValBinds NoExtField (ValBinds NoExtField bag lsigs) -> do
+  HsValBinds epAnn (ValBinds _ bag lsigs) -> pseudoLocated epAnn $ do
     -- When in a single-line layout, there is a chance that the inner
     -- elements will also contain semicolons and they will confuse the
     -- parser. so we request braces around every element except the last.
@@ -509,33 +528,63 @@
         p_item' (p, item) =
           positionToBracing p $
             withSpacing (either p_valDecl p_sigDecl) item
-        binds = sortBy (leftmost_smallest `on` getLoc) items
+        binds = sortBy (leftmost_smallest `on` getLocA) items
     sitcc $ sepSemi p_item' (attachRelativePos binds)
-  HsValBinds NoExtField _ -> notImplemented "HsValBinds"
-  HsIPBinds NoExtField (IPBinds NoExtField xs) ->
+  HsValBinds _ _ -> notImplemented "HsValBinds"
+  HsIPBinds epAnn (IPBinds _ xs) -> pseudoLocated epAnn $ do
     -- Second argument of IPBind is always Left before type-checking.
-    let p_ipBind (IPBind NoExtField (Left name) expr) = do
+    let p_ipBind (IPBind _ (Left name) expr) = do
           atom name
           space
           equals
           breakpoint
           useBraces $ inci $ located expr p_hsExpr
-        p_ipBind (IPBind NoExtField (Right _) _) =
+        p_ipBind (IPBind _ (Right _) _) =
           -- Should only occur after the type checker
           notImplemented "IPBind _ (Right _) _"
-     in sepSemi (located' p_ipBind) xs
-  EmptyLocalBinds NoExtField -> return ()
+    sepSemi (located' p_ipBind) xs
+  EmptyLocalBinds _ -> return ()
+  where
+    -- HsLocalBinds is no longer wrapped in a Located (see call sites
+    -- of p_hsLocalBinds). Hence, we introduce a manual Located as we
+    -- depend on the layout being correctly set.
+    pseudoLocated = \case
+      EpAnn {anns = AnnList {al_anchor = Just Anchor {anchor}}} ->
+        located (L (RealSrcSpan anchor Nothing) ()) . const
+      _ -> id
 
+p_lhsFieldLabel :: Located (HsFieldLabel GhcPs) -> R ()
+p_lhsFieldLabel = located' $ p_lFieldLabelString . hflLabel
+  where
+    p_lFieldLabelString (L s fs) = parensIfOp . atom @FastString $ fs
+      where
+        -- HACK For OverloadedRecordUpdate:
+        -- In operator field updates (i.e. `f {(+) = 1}`), we don't have
+        -- information whether parens are necessary. As a workaround,
+        -- we look if the RealSrcSpan is bigger than the string fs.
+        parensIfOp
+          | isOneLineSpan s,
+            Just realS <- srcSpanToRealSrcSpan s,
+            let spanLength = srcSpanEndCol realS - srcSpanStartCol realS,
+            lengthFS fs < spanLength =
+              parens N
+          | otherwise = id
+
+p_fieldLabels :: [Located (HsFieldLabel GhcPs)] -> R ()
+p_fieldLabels flss =
+  sep (txt ".") p_lhsFieldLabel flss
+
 p_hsRecField ::
-  HsRecField' RdrName (LHsExpr GhcPs) ->
+  (id -> R ()) ->
+  HsRecField' id (LHsExpr GhcPs) ->
   R ()
-p_hsRecField HsRecField {..} = do
-  p_rdrName hsRecFieldLbl
+p_hsRecField p_lbl HsRecField {..} = do
+  located hsRecFieldLbl p_lbl
   unless hsRecPun $ do
     space
     equals
     let placement =
-          if onTheSameLine (getLoc hsRecFieldLbl) (getLoc hsRecFieldArg)
+          if onTheSameLine (getLoc hsRecFieldLbl) (getLocA hsRecFieldArg)
             then exprPlacement (unLoc hsRecFieldArg)
             else Normal
     placeHanging placement (located hsRecFieldArg p_hsExpr)
@@ -545,30 +594,30 @@
 
 p_hsExpr' :: BracketStyle -> HsExpr GhcPs -> R ()
 p_hsExpr' s = \case
-  HsVar NoExtField name -> p_rdrName name
-  HsUnboundVar NoExtField occ -> atom occ
-  HsConLikeOut NoExtField _ -> notImplemented "HsConLikeOut"
-  HsRecFld NoExtField x ->
+  HsVar _ name -> p_rdrName name
+  HsUnboundVar _ occ -> atom occ
+  HsConLikeOut _ _ -> notImplemented "HsConLikeOut"
+  HsRecFld _ x ->
     case x of
-      Unambiguous NoExtField name -> p_rdrName name
-      Ambiguous NoExtField name -> p_rdrName name
-  HsOverLabel NoExtField _ v -> do
+      Unambiguous _ name -> p_rdrName name
+      Ambiguous _ name -> p_rdrName name
+  HsOverLabel _ v -> do
     txt "#"
     atom v
-  HsIPVar NoExtField (HsIPName name) -> do
+  HsIPVar _ (HsIPName name) -> do
     txt "?"
     atom name
-  HsOverLit NoExtField v -> atom (ol_val v)
-  HsLit NoExtField lit ->
+  HsOverLit _ v -> atom (ol_val v)
+  HsLit _ lit ->
     case lit of
       HsString (SourceText stxt) _ -> p_stringLit stxt
       HsStringPrim (SourceText stxt) _ -> p_stringLit stxt
       r -> atom r
-  HsLam NoExtField mgroup ->
+  HsLam _ mgroup ->
     p_matchGroup Lambda mgroup
-  HsLamCase NoExtField mgroup ->
+  HsLamCase _ mgroup ->
     p_lamcase exprPlacement p_hsExpr mgroup
-  HsApp NoExtField f x -> do
+  HsApp _ f x -> do
     let -- In order to format function applications with multiple parameters
         -- nicer, traverse the AST to gather the function and all the
         -- parameters together.
@@ -582,7 +631,7 @@
         (initp, lastp) = (NE.init args, NE.last args)
         initSpan =
           combineSrcSpans' $
-            getLoc f :| [(srcLocSpan . srcSpanStart . getLoc) lastp]
+            getLocA f :| [(srcLocSpan . srcSpanStart . getLocA) lastp]
         -- Hang the last argument only if the initial arguments span one
         -- line.
         placement =
@@ -604,14 +653,14 @@
             -- Thus, we indent by half of indentStep when the function is
             -- a multi line do block or case expression.
             indentArg
-              | isOneLineSpan (getLoc func) = case unLoc func of
-                HsDo {} -> inciBy 2
-                _ -> inci
+              | isOneLineSpan (getLocA func) = case unLoc func of
+                  HsDo {} -> inciBy 2
+                  _ -> inci
               | otherwise = case unLoc func of
-                HsDo {} -> inciHalf
-                HsCase {} -> inciHalf
-                HsLamCase {} -> inciHalf
-                _ -> inci
+                  HsDo {} -> inciHalf
+                  HsCase {} -> inciHalf
+                  HsLamCase {} -> inciHalf
+                  _ -> inci
         ub <-
           getLayout <&> \case
             SingleLine -> useBraces
@@ -630,7 +679,7 @@
           sep breakpoint (located' p_hsExpr) initp
         placeHanging placement . dontUseBraces $
           located lastp p_hsExpr
-  HsAppType NoExtField e a -> do
+  HsAppType _ e a -> do
     located e p_hsExpr
     breakpoint
     inci $ do
@@ -641,10 +690,10 @@
         HsSpliceTy {} -> space
         _ -> return ()
       located (hswc_body a) p_hsType
-  OpApp NoExtField x op y -> do
+  OpApp _ x op y -> do
     let opTree = OpBranch (exprOpTree x) op (exprOpTree y)
     p_exprOpTree s (reassociateOpTree getOpName opTree)
-  NegApp NoExtField e NoExtField -> do
+  NegApp _ e _ -> do
     negativeLiterals <- isExtensionEnabled NegativeLiterals
     let isLiteral = case unLoc e of
           HsLit {} -> True
@@ -655,51 +704,49 @@
     -- negated literals, as `- 1` and `-1` have differing AST.
     when (negativeLiterals && isLiteral) space
     located e p_hsExpr
-  HsPar NoExtField e -> do
-    parens s $ sitcc $ located e $ dontUseBraces . p_hsExpr
-  SectionL NoExtField x op -> do
+  HsPar _ e ->
+    parens s $ sitcc (located e (dontUseBraces . p_hsExpr))
+  SectionL _ x op -> do
     located x p_hsExpr
     breakpoint
     inci (located op p_hsExpr)
-  SectionR NoExtField op x -> do
+  SectionR _ op x -> do
     located op p_hsExpr
-    useRecordDot' <- useRecordDot
-    let isRecordDot' = isRecordDot (unLoc op) (getLoc x)
-    unless (useRecordDot' && isRecordDot') breakpoint
+    breakpoint
     inci (located x p_hsExpr)
-  ExplicitTuple NoExtField args boxity ->
-    let isSection = any (isMissing . unLoc) args
+  ExplicitTuple _ args boxity -> do
+    let isSection = any isMissing args
         isMissing = \case
-          Missing NoExtField -> True
+          Missing _ -> True
           _ -> False
         p_arg = \case
-          Present NoExtField x -> located x p_hsExprListItem
-          Missing NoExtField -> pure ()
-        p_larg = sitcc . located' p_arg
+          Present _ x -> located x p_hsExprListItem
+          Missing _ -> pure ()
         parens' =
           case boxity of
             Boxed -> parens
             Unboxed -> parensHash
-     in if isSection
-          then
-            switchLayout [] . parens' s $
-              sep comma p_larg args
-          else
-            switchLayout (getLoc <$> args) . parens' s $
-              sep commaDel p_larg args
-  ExplicitSum NoExtField tag arity e ->
+    enclSpan <- fmap (flip RealSrcSpan Nothing) . maybeToList <$> getEnclosingSpan (const True)
+    if isSection
+      then
+        switchLayout [] . parens' s $
+          sep comma p_arg args
+      else
+        switchLayout enclSpan . parens' s $
+          sep commaDel p_arg args
+  ExplicitSum _ tag arity e ->
     p_unboxedSum N tag arity (located e p_hsExpr)
-  HsCase NoExtField e mgroup ->
+  HsCase _ e mgroup ->
     p_case exprPlacement p_hsExpr e mgroup
-  HsIf NoExtField if' then' else' ->
+  HsIf _ if' then' else' ->
     p_if exprPlacement p_hsExpr if' then' else'
-  HsMultiIf NoExtField guards -> do
+  HsMultiIf _ guards -> do
     txt "if"
     breakpoint
     inci . inci $ sep newline (located' (p_grhs RightArrow)) guards
-  HsLet NoExtField localBinds e ->
+  HsLet _ localBinds e ->
     p_let p_hsExpr localBinds e
-  HsDo NoExtField ctx es -> do
+  HsDo _ ctx es -> do
     let doBody moduleName header = do
           forM_ moduleName $ \m -> atom m *> txt "."
           txt header
@@ -710,14 +757,10 @@
                   (breakpoint >> txt "|" >> space)
                   p_seqBody
               p_seqBody =
-                sitcc'
+                sitccIfTrailing
                   . sep
                     commaDel
                     (located' (sitcc . p_stmt))
-              sitcc' x =
-                getPrinterOpt poCommaStyle >>= \case
-                  Leading -> id x
-                  Trailing -> sitcc x
               stmts = init xs
               yield = last xs
               lists = foldr (liftAppend . gatherStmt) [] stmts
@@ -736,19 +779,15 @@
       PatGuard _ -> notImplemented "PatGuard"
       ParStmtCtxt _ -> notImplemented "ParStmtCtxt"
       TransStmtCtxt _ -> notImplemented "TransStmtCtxt"
-  ExplicitList _ _ xs ->
+  ExplicitList _ xs ->
     brackets s $
       sep commaDel (sitcc . located' p_hsExprListItem) xs
   RecordCon {..} -> do
-    located rcon_con_name atom
+    located rcon_con atom
     breakpointPreRecordBrace
     let HsRecFields {..} = rcon_flds
-        updName f =
-          (f :: HsRecField GhcPs (LHsExpr GhcPs))
-            { hsRecFieldLbl = case unLoc $ hsRecFieldLbl f of
-                FieldOcc _ n -> n
-            }
-        fields = located' (p_hsRecField . updName) <$> rec_flds
+        p_lbl = p_rdrName . rdrNameFieldOcc
+        fields = located' (p_hsRecField p_lbl) <$> rec_flds
         dotdot =
           case rec_dotdot of
             Just {} -> [txt ".."]
@@ -757,37 +796,32 @@
       sep commaDel sitcc (fields <> dotdot)
   RecordUpd {..} -> do
     located rupd_expr p_hsExpr
-    useRecordDot' <- useRecordDot
-    let mrs sp = case getLoc sp of
-          RealSrcSpan r _ -> Just r
-          _ -> Nothing
-    let isPluginForm =
-          ((1 +) . srcSpanEndCol <$> mrs rupd_expr)
-            == (srcSpanStartCol <$> mrs (head rupd_flds))
-            && onTheSameLine (getLoc rupd_expr) (getLoc $ head rupd_flds)
-    unless (useRecordDot' && isPluginForm) breakpointPreRecordBrace
-    let updName f =
-          (f :: HsRecUpdField GhcPs)
-            { hsRecFieldLbl = case unLoc $ hsRecFieldLbl f of
-                Ambiguous _ n -> n
-                Unambiguous _ n -> n
-            }
-        updBraces =
-          if useRecordDot' && isPluginForm
-            then recordDotBraces
-            else inci . braces N
-    updBraces $
-      sep
-        commaDel
-        (sitcc . located' (p_hsRecField . updName))
+    breakpointPreRecordBrace
+    let p_updLbl =
+          p_rdrName . \case
+            Unambiguous NoExtField n -> n
+            Ambiguous NoExtField n -> n
+        p_recFields p_lbl =
+          sep commaDel (sitcc . located' (p_hsRecField p_lbl))
+    inci . braces N $
+      either
+        (p_recFields p_updLbl)
+        (p_recFields (p_fieldLabels . coerce))
         rupd_flds
-  ExprWithTySig NoExtField x HsWC {hswc_body = HsIB {..}} -> sitcc $ do
+  HsGetField {..} -> do
+    located gf_expr p_hsExpr
+    txt "."
+    p_lhsFieldLabel gf_field
+  HsProjection {..} -> parens N $ do
+    txt "."
+    p_fieldLabels (NE.toList proj_flds)
+  ExprWithTySig _ x HsWC {hswc_body} -> sitcc $ do
     located x p_hsExpr
     space
     txt "::"
     breakpoint
-    inci $ located hsib_body p_hsType
-  ArithSeq NoExtField _ x ->
+    inci $ located hswc_body p_hsSigType
+  ArithSeq _ _ x ->
     case x of
       From from -> brackets s $ do
         located from p_hsExpr
@@ -809,11 +843,11 @@
         txt ".."
         space
         located to p_hsExpr
-  HsBracket NoExtField x -> p_hsBracket x
+  HsBracket epAnn x -> p_hsBracket epAnn x
   HsRnBracketOut {} -> notImplemented "HsRnBracketOut"
   HsTcBracketOut {} -> notImplemented "HsTcBracketOut"
-  HsSpliceE NoExtField splice -> p_hsSplice splice
-  HsProc NoExtField p e -> do
+  HsSpliceE _ splice -> p_hsSplice splice
+  HsProc _ p e -> do
     txt "proc"
     located p $ \x -> do
       breakpoint
@@ -828,14 +862,13 @@
     inci (located e p_hsExpr)
   HsTick {} -> notImplemented "HsTick"
   HsBinTick {} -> notImplemented "HsBinTick"
-  HsPragE NoExtField prag x -> case prag of
-    HsPragSCC NoExtField _ name -> do
+  HsPragE _ prag x -> case prag of
+    HsPragSCC _ _ name -> do
       txt "{-# SCC "
       atom name
       txt " #-}"
       breakpoint
       located x p_hsExpr
-    HsPragTick {} -> notImplemented "HsTickPragma"
 
 p_patSynBind :: PatSynBind GhcPs GhcPs -> R ()
 p_patSynBind PSB {..} = do
@@ -860,25 +893,26 @@
             inci (p_matchGroup (Function psb_id) mgroup)
   txt "pattern"
   case psb_args of
-    PrefixCon xs -> do
+    PrefixCon [] xs -> do
       space
       p_rdrName psb_id
       inci $ do
-        switchLayout (getLoc <$> xs) $ do
+        switchLayout (getLocA <$> xs) $ do
           unless (null xs) breakpoint
           sitcc (sep breakpoint p_rdrName xs)
         rhs
+    PrefixCon (v : _) _ -> absurd v
     RecCon xs -> do
       space
       p_rdrName psb_id
       inci $ do
-        switchLayout (getLoc . recordPatSynPatVar <$> xs) $ do
+        switchLayout (getLocA . recordPatSynPatVar <$> xs) $ do
           unless (null xs) breakpointPreRecordBrace
           braces N $
             sep commaDel (p_rdrName . recordPatSynPatVar) xs
         rhs
     InfixCon l r -> do
-      switchLayout [getLoc l, getLoc r] $ do
+      switchLayout [getLocA l, getLocA r] $ do
         space
         p_rdrName l
         breakpoint
@@ -889,7 +923,9 @@
       inci rhs
 
 p_case ::
-  Data body =>
+  ( Anno (GRHS GhcPs (LocatedA body)) ~ SrcSpan,
+    Anno (Match GhcPs (LocatedA body)) ~ SrcSpanAnnA
+  ) =>
   -- | Placer
   (body -> Placement) ->
   -- | Render
@@ -897,7 +933,7 @@
   -- | Expression
   LHsExpr GhcPs ->
   -- | Match group
-  MatchGroup GhcPs (Located body) ->
+  MatchGroup GhcPs (LocatedA body) ->
   R ()
 p_case placer render e mgroup = do
   txt "case"
@@ -909,13 +945,15 @@
   inci (p_matchGroup' placer render Case mgroup)
 
 p_lamcase ::
-  Data body =>
+  ( Anno (GRHS GhcPs (LocatedA body)) ~ SrcSpan,
+    Anno (Match GhcPs (LocatedA body)) ~ SrcSpanAnnA
+  ) =>
   -- | Placer
   (body -> Placement) ->
   -- | Render
   (body -> R ()) ->
   -- | Expression
-  MatchGroup GhcPs (Located body) ->
+  MatchGroup GhcPs (LocatedA body) ->
   R ()
 p_lamcase placer render mgroup = do
   txt "\\case"
@@ -923,7 +961,6 @@
   inci (p_matchGroup' placer render LambdaCase mgroup)
 
 p_if ::
-  Data body =>
   -- | Placer
   (body -> Placement) ->
   -- | Render
@@ -931,9 +968,9 @@
   -- | If
   LHsExpr GhcPs ->
   -- | Then
-  Located body ->
+  LocatedA body ->
   -- | Else
-  Located body ->
+  LocatedA body ->
   R ()
 p_if placer render if' then' else' = do
   txt "if"
@@ -952,16 +989,15 @@
       placeHanging (placer x) (render x)
 
 p_let ::
-  Data body =>
   -- | Render
   (body -> R ()) ->
-  Located (HsLocalBindsLR GhcPs GhcPs) ->
-  Located body ->
+  HsLocalBinds GhcPs ->
+  LocatedA body ->
   R ()
 p_let render localBinds e = sitcc $ do
   txt "let"
   space
-  dontUseBraces $ sitcc (located localBinds p_hsLocalBinds)
+  dontUseBraces $ sitcc (p_hsLocalBinds localBinds)
   vlayout space (newline >> txt " ")
   txt "in"
   space
@@ -969,37 +1005,39 @@
 
 p_pat :: Pat GhcPs -> R ()
 p_pat = \case
-  WildPat NoExtField -> txt "_"
-  VarPat NoExtField name -> p_rdrName name
-  LazyPat NoExtField pat -> do
+  WildPat _ -> txt "_"
+  VarPat _ name -> p_rdrName name
+  LazyPat _ pat -> do
     txt "~"
     located pat p_pat
-  AsPat NoExtField name pat -> do
+  AsPat _ name pat -> do
     p_rdrName name
     txt "@"
     located pat p_pat
-  ParPat NoExtField pat ->
+  ParPat _ pat ->
     located pat (parens S . sitcc . p_pat)
-  BangPat NoExtField pat -> do
+  BangPat _ pat -> do
     txt "!"
     located pat p_pat
-  ListPat NoExtField pats ->
+  ListPat _ pats ->
     brackets S $ sep commaDel (located' p_pat) pats
-  TuplePat NoExtField pats boxing -> do
+  TuplePat _ pats boxing -> do
     let parens' =
           case boxing of
             Boxed -> parens S
             Unboxed -> parensHash S
     parens' $ sep commaDel (sitcc . located' p_pat) pats
-  SumPat NoExtField pat tag arity ->
+  SumPat _ pat tag arity ->
     p_unboxedSum S tag arity (located pat p_pat)
-  ConPat NoExtField pat details ->
+  ConPat _ pat details ->
     case details of
-      PrefixCon xs -> sitcc $ do
+      PrefixCon [] xs -> sitcc $ do
         p_rdrName pat
         unless (null xs) $ do
           breakpoint
           inci . sitcc $ sep breakpoint (sitcc . located' p_pat) xs
+      -- The first field of PrefixCon is filled in later stages
+      PrefixCon {} -> notImplemented "Unexpected types in constructor pattern"
       RecCon (HsRecFields fields dotdot) -> do
         p_rdrName pat
         breakpointPreRecordBrace
@@ -1011,42 +1049,41 @@
             Nothing -> Just <$> fields
             Just (L _ n) -> (Just <$> take n fields) ++ [Nothing]
       InfixCon l r -> do
-        switchLayout [getLoc l, getLoc r] $ do
+        switchLayout [getLocA l, getLocA r] $ do
           located l p_pat
           breakpoint
           inci $ do
             p_rdrName pat
             space
             located r p_pat
-  ViewPat NoExtField expr pat -> sitcc $ do
+  ViewPat _ expr pat -> sitcc $ do
     located expr p_hsExpr
     space
     txt "->"
     breakpoint
     inci (located pat p_pat)
-  SplicePat NoExtField splice -> p_hsSplice splice
-  LitPat NoExtField p -> atom p
-  NPat NoExtField v (isJust -> isNegated) NoExtField -> do
+  SplicePat _ splice -> p_hsSplice splice
+  LitPat _ p -> atom p
+  NPat _ v (isJust -> isNegated) _ -> do
     when isNegated $ do
       txt "-"
       negativeLiterals <- isExtensionEnabled NegativeLiterals
       when negativeLiterals space
     located v (atom . ol_val)
-  NPlusKPat NoExtField n k _ _ _ -> sitcc $ do
+  NPlusKPat _ n k _ _ _ -> sitcc $ do
     p_rdrName n
     breakpoint
     inci $ do
       txt "+"
       space
       located k (atom . ol_val)
-  SigPat NoExtField pat HsPS {..} -> do
+  SigPat _ pat HsPS {..} -> do
     located pat p_pat
-    p_typeAscription (HsWC NoExtField (HsIB NoExtField hsps_body))
+    p_typeAscription (lhsTypeToSigType hsps_body)
 
 p_pat_hsRecField :: HsRecField' (FieldOcc GhcPs) (LPat GhcPs) -> R ()
 p_pat_hsRecField HsRecField {..} = do
-  located hsRecFieldLbl $ \x ->
-    p_rdrName (rdrNameFieldOcc x)
+  located hsRecFieldLbl $ p_rdrName . rdrNameFieldOcc
   unless hsRecPun $ do
     space
     equals
@@ -1070,11 +1107,11 @@
 
 p_hsSplice :: HsSplice GhcPs -> R ()
 p_hsSplice = \case
-  HsTypedSplice NoExtField deco _ expr -> p_hsSpliceTH True expr deco
-  HsUntypedSplice NoExtField deco _ expr -> p_hsSpliceTH False expr deco
-  HsQuasiQuote NoExtField _ quoterName srcSpan str -> do
+  HsTypedSplice _ deco _ expr -> p_hsSpliceTH True expr deco
+  HsUntypedSplice _ deco _ expr -> p_hsSpliceTH False expr deco
+  HsQuasiQuote _ _ quoterName _ str -> do
     txt "["
-    p_rdrName (L srcSpan quoterName)
+    p_rdrName (noLocA quoterName)
     txt "|"
     -- QuasiQuoters often rely on precise custom strings. We cannot do any
     -- formatting here without potentially breaking someone's code.
@@ -1099,34 +1136,21 @@
   where
     decoSymbol = if isTyped then "$$" else "$"
 
-p_hsBracket :: HsBracket GhcPs -> R ()
-p_hsBracket = \case
-  ExpBr NoExtField expr -> do
-    anns <- getEnclosingAnns
-    let name = case anns of
-          AnnOpenEQ : _ -> ""
-          _ -> "e"
+p_hsBracket :: EpAnn [AddEpAnn] -> HsBracket GhcPs -> R ()
+p_hsBracket epAnn = \case
+  ExpBr _ expr -> do
+    let name
+          | or [True | AddEpAnn AnnOpenEQ _ <- epAnnAnns epAnn] = ""
+          | otherwise = "e"
     quote name (located expr p_hsExpr)
-  PatBr NoExtField pat -> located pat (quote "p" . p_pat)
-  DecBrL NoExtField decls -> quote "d" (handleStarIsType decls (p_hsDecls Free decls))
-  DecBrG NoExtField _ -> notImplemented "DecBrG" -- result of renamer
-  TypBr NoExtField ty -> quote "t" (located ty (handleStarIsType ty . p_hsType))
-  VarBr NoExtField isSingleQuote name -> do
+  PatBr _ pat -> located pat (quote "p" . p_pat)
+  DecBrL _ decls -> quote "d" (handleStarIsType decls (p_hsDecls Free decls))
+  DecBrG _ _ -> notImplemented "DecBrG" -- result of renamer
+  TypBr _ ty -> quote "t" (located ty (handleStarIsType ty . p_hsType))
+  VarBr _ isSingleQuote name -> do
     txt (bool "''" "'" isSingleQuote)
-    -- HACK As you can see we use 'noLoc' here to be able to pass name into
-    -- 'p_rdrName' since the latter expects a "located" thing. The problem
-    -- is that 'VarBr' doesn't provide us with location of the name. This in
-    -- turn makes it impossible to detect if there are parentheses around
-    -- it, etc. So we have to add parentheses manually assuming they are
-    -- necessary for all operators.
-    let isOperator =
-          all
-            (\i -> isPunctuation i || isSymbol i)
-            (showOutputable (rdrNameOcc name))
-            && not (doesNotNeedExtraParens name)
-        wrapper = if isOperator then parens N else id
-    wrapper $ p_rdrName (noLoc name)
-  TExpBr NoExtField expr -> do
+    p_rdrName name
+  TExpBr _ expr -> do
     txt "[||"
     breakpoint'
     located expr p_hsExpr
@@ -1222,9 +1246,9 @@
 liftAppend (x : xs) [] = x : xs
 liftAppend (x : xs) (y : ys) = x <> y : liftAppend xs ys
 
-getGRHSSpan :: GRHS GhcPs (Located body) -> SrcSpan
-getGRHSSpan (GRHS NoExtField guards body) =
-  combineSrcSpans' $ getLoc body :| map getLoc guards
+getGRHSSpan :: GRHS GhcPs (LocatedA body) -> SrcSpan
+getGRHSSpan (GRHS _ guards body) =
+  combineSrcSpans' $ getLocA body :| map getLocA guards
 
 -- | Place a thing that may have a hanging form. This function handles how
 -- to separate it from preceding expressions and whether to bump indentation
@@ -1243,63 +1267,62 @@
 -- form.
 blockPlacement ::
   (body -> Placement) ->
-  [LGRHS GhcPs (Located body)] ->
+  [LGRHS GhcPs (LocatedA body)] ->
   Placement
-blockPlacement placer [L _ (GRHS NoExtField _ (L _ x))] = placer x
+blockPlacement placer [L _ (GRHS _ _ (L _ x))] = placer x
 blockPlacement _ _ = Normal
 
 -- | Check if given command has a hanging form.
 cmdPlacement :: HsCmd GhcPs -> Placement
 cmdPlacement = \case
-  HsCmdLam NoExtField _ -> Hanging
-  HsCmdCase NoExtField _ _ -> Hanging
-  HsCmdLamCase NoExtField _ -> Hanging
-  HsCmdDo NoExtField _ -> Hanging
+  HsCmdLam _ _ -> Hanging
+  HsCmdCase _ _ _ -> Hanging
+  HsCmdLamCase _ _ -> Hanging
+  HsCmdDo _ _ -> Hanging
   _ -> Normal
 
 cmdTopPlacement :: HsCmdTop GhcPs -> Placement
-cmdTopPlacement (HsCmdTop NoExtField (L _ x)) = cmdPlacement x
+cmdTopPlacement (HsCmdTop _ (L _ x)) = cmdPlacement x
 
 -- | Check if given expression has a hanging form.
 exprPlacement :: HsExpr GhcPs -> Placement
 exprPlacement = \case
   -- Only hang lambdas with single line parameter lists
-  HsLam NoExtField mg -> case mg of
-    MG _ (L _ [L _ (Match NoExtField _ (x : xs) _)]) _
-      | isOneLineSpan (combineSrcSpans' $ fmap getLoc (x :| xs)) ->
-        Hanging
+  HsLam _ mg -> case mg of
+    MG _ (L _ [L _ (Match _ _ (x : xs) _)]) _
+      | isOneLineSpan (combineSrcSpans' $ fmap getLocA (x :| xs)) ->
+          Hanging
     _ -> Normal
-  HsLamCase NoExtField _ -> Hanging
-  HsCase NoExtField _ _ -> Hanging
-  HsDo NoExtField (DoExpr _) _ -> Hanging
-  HsDo NoExtField (MDoExpr _) _ -> Hanging
-  OpApp NoExtField _ op y ->
+  HsLamCase _ _ -> Hanging
+  HsCase _ _ _ -> Hanging
+  HsDo _ (DoExpr _) _ -> Hanging
+  HsDo _ (MDoExpr _) _ -> Hanging
+  OpApp _ _ op y ->
     case (fmap getOpNameStr . getOpName . unLoc) op of
       Just "$" -> exprPlacement (unLoc y)
       _ -> Normal
-  HsApp NoExtField _ y -> exprPlacement (unLoc y)
-  HsProc NoExtField p _ ->
+  HsApp _ _ y -> exprPlacement (unLoc y)
+  HsProc _ p _ ->
     -- Indentation breaks if pattern is longer than one line and left
     -- hanging. Consequently, only apply hanging when it is safe.
-    if isOneLineSpan (getLoc p)
+    if isOneLineSpan (getLocA p)
       then Hanging
       else Normal
   _ -> Normal
 
-withGuards :: [LGRHS GhcPs (Located body)] -> Bool
+withGuards :: [LGRHS GhcPs body] -> Bool
 withGuards = any (checkOne . unLoc)
   where
-    checkOne :: GRHS GhcPs (Located body) -> Bool
-    checkOne (GRHS NoExtField [] _) = False
+    checkOne (GRHS _ [] _) = False
     checkOne _ = True
 
 exprOpTree :: LHsExpr GhcPs -> OpTree (LHsExpr GhcPs) (LHsExpr GhcPs)
-exprOpTree (L _ (OpApp NoExtField x op y)) = OpBranch (exprOpTree x) op (exprOpTree y)
+exprOpTree (L _ (OpApp _ x op y)) = OpBranch (exprOpTree x) op (exprOpTree y)
 exprOpTree n = OpNode n
 
 getOpName :: HsExpr GhcPs -> Maybe RdrName
 getOpName = \case
-  HsVar NoExtField (L _ a) -> Just a
+  HsVar _ (L _ a) -> Just a
   _ -> Nothing
 
 getOpNameStr :: RdrName -> String
@@ -1316,71 +1339,60 @@
       -- Distinguish holes used in infix notation.
       -- eg. '1 _foo 2' and '1 `_foo` 2'
       opWrapper = case unLoc op of
-        HsUnboundVar NoExtField _ -> backticks
+        HsUnboundVar _ _ -> backticks
         _ -> id
   ub <- opBranchBraceStyle placement
   let opNameStr = (fmap getOpNameStr . getOpName . unLoc) op
       gotDollar = opNameStr == Just "$"
       gotColon = opNameStr == Just ":"
-      gotRecordDot = isRecordDot (unLoc op) (opTreeLoc y)
       lhs =
         switchLayout [opTreeLoc x] $
           p_exprOpTree s x
       p_op = located op (opWrapper . p_hsExpr)
       p_y = switchLayout [opTreeLoc y] (p_exprOpTree N y)
-      isSection = case (opTreeLoc x, getLoc op) of
-        (RealSrcSpan treeSpan _, RealSrcSpan opSpan _) ->
-          srcSpanEndCol treeSpan /= srcSpanStartCol opSpan
-        _ -> False
       isDoBlock = \case
         OpNode (L _ HsDo {}) -> True
         _ -> False
-  useRecordDot' <- useRecordDot
   if
       | gotColon -> do
-        ub lhs
-        space
-        p_op
-        case placement of
-          Hanging -> do
-            space
-            p_y
-          Normal -> do
-            breakpoint
-            inciIf (isDoBlock y) p_y
+          ub lhs
+          space
+          p_op
+          case placement of
+            Hanging -> do
+              space
+              p_y
+            Normal -> do
+              breakpoint
+              inciIf (isDoBlock y) p_y
       | gotDollar
           && isOneLineSpan (opTreeLoc x)
           && placement == Normal -> do
-        useBraces lhs
-        space
-        p_op
-        breakpoint
-        inci p_y
-      | useRecordDot' && gotRecordDot -> do
-        lhs
-        when isSection space
-        p_op
-        p_y
+          useBraces lhs
+          space
+          p_op
+          breakpoint
+          inci p_y
       | otherwise -> do
-        ub lhs
-        let opAndRhs = do
-              p_op
-              space
-              p_y
-        case x of
-          -- This case prevents an operator from being indented past the start of a `do` block
-          -- constituting its left operand, thus altering the AST.
-          -- This is only relevant when the `do` block is on one line, as otherwise we will
-          -- insert a newline after `do` anyway.
-          OpNode (unLoc -> HsDo _ _ _) | isOneLineSpan (opTreeLoc x) -> breakpoint >> opAndRhs
-          _ -> placeHanging placement opAndRhs
+          ub lhs
+          let opAndRhs = do
+                p_op
+                space
+                p_y
+          case x of
+            -- This case prevents an operator from being indented past the start of a `do` block
+            -- constituting its left operand, thus altering the AST.
+            -- This is only relevant when the `do` block is on one line, as otherwise we will
+            -- insert a newline after `do` anyway.
+            OpNode (unLoc -> HsDo _ _ _) | isOneLineSpan (opTreeLoc x) -> breakpoint >> opAndRhs
+            _ -> placeHanging placement opAndRhs
 
 pattern CmdTopCmd :: HsCmd GhcPs -> LHsCmdTop GhcPs
-pattern CmdTopCmd cmd <- (L _ (HsCmdTop NoExtField (L _ cmd)))
+pattern CmdTopCmd cmd <- (L _ (HsCmdTop _ (L _ cmd)))
 
 cmdOpTree :: LHsCmdTop GhcPs -> OpTree (LHsCmdTop GhcPs) (LHsExpr GhcPs)
 cmdOpTree = \case
-  CmdTopCmd (HsCmdArrForm NoExtField op Infix _ [x, y]) ->
+  CmdTopCmd (HsCmdArrForm _ op Infix _ [x, y]) ->
     OpBranch (cmdOpTree x) op (cmdOpTree y)
   n -> OpNode n
 
@@ -1397,12 +1409,13 @@
       p_cmdOpTree y
 
 opBranchPlacement ::
+  HasSrcSpan l =>
   -- | Placement of nodes
   (ty -> Placement) ->
   -- | Left branch
-  OpTree (Located ty) op ->
+  OpTree (GenLocated l ty) op ->
   -- | Right branch
-  OpTree (Located ty) op ->
+  OpTree (GenLocated l ty) op ->
   Placement
 opBranchPlacement f x y
   -- If the beginning of the first argument and the second argument are on
@@ -1410,7 +1423,7 @@
   -- placement.
   | isOneLineSpan (mkSrcSpan (srcSpanStart (opTreeLoc x)) (srcSpanStart (opTreeLoc y))),
     OpNode (L _ n) <- y =
-    f n
+      f n
   | otherwise = Normal
 
 opBranchBraceStyle :: Placement -> R (R () -> R ())
@@ -1420,27 +1433,6 @@
     MultiLine -> case placement of
       Hanging -> useBraces
       Normal -> dontUseBraces
-
--- | Return 'True' if given expression is a record-dot operator expression.
-isRecordDot ::
-  -- | Operator expression
-  HsExpr GhcPs ->
-  -- | Span of the expression on the right-hand side of the operator
-  SrcSpan ->
-  Bool
-isRecordDot op (RealSrcSpan ySpan _) = case op of
-  HsVar NoExtField (L (RealSrcSpan opSpan _) opName) ->
-    (getOpNameStr opName == ".") && (srcSpanEndCol opSpan == srcSpanStartCol ySpan)
-  _ -> False
-isRecordDot _ _ = False
-
--- | Get annotations for the enclosing element.
-getEnclosingAnns :: R [AnnKeywordId]
-getEnclosingAnns = do
-  e <- getEnclosingSpan (const True)
-  case e of
-    Nothing -> return []
-    Just e' -> getAnns (RealSrcSpan e' Nothing)
 
 -- | For use before record braces. Collapse to empty if not 'poRecordBraceSpace'.
 breakpointPreRecordBrace :: R ()
diff --git a/src/Ormolu/Printer/Meat/Declaration/Warning.hs b/src/Ormolu/Printer/Meat/Declaration/Warning.hs
--- a/src/Ormolu/Printer/Meat/Declaration/Warning.hs
+++ b/src/Ormolu/Printer/Meat/Declaration/Warning.hs
@@ -9,20 +9,20 @@
 
 import Data.Foldable
 import Data.Text (Text)
-import GHC.Hs.Decls
-import GHC.Hs.Extension
-import GHC.Types.Basic
+import GHC.Hs
 import GHC.Types.Name.Reader
+import GHC.Types.SourceText
 import GHC.Types.SrcLoc
+import GHC.Unit.Module.Warnings
 import Ormolu.Printer.Combinators
 import Ormolu.Printer.Meat.Common
 
 p_warnDecls :: WarnDecls GhcPs -> R ()
-p_warnDecls (Warnings NoExtField _ warnings) =
+p_warnDecls (Warnings _ _ warnings) =
   traverse_ (located' p_warnDecl) warnings
 
 p_warnDecl :: WarnDecl GhcPs -> R ()
-p_warnDecl (Warning NoExtField functions warningTxt) =
+p_warnDecl (Warning _ functions warningTxt) =
   p_topLevelWarning functions warningTxt
 
 p_moduleWarning :: WarningTxt -> R ()
@@ -30,10 +30,10 @@
   let (pragmaText, lits) = warningText wtxt
   inci $ pragma pragmaText $ inci $ p_lits lits
 
-p_topLevelWarning :: [Located RdrName] -> WarningTxt -> R ()
+p_topLevelWarning :: [LocatedN RdrName] -> WarningTxt -> R ()
 p_topLevelWarning fnames wtxt = do
   let (pragmaText, lits) = warningText wtxt
-  switchLayout (fmap getLoc fnames ++ fmap getLoc lits) $
+  switchLayout (fmap getLocA fnames ++ fmap getLoc lits) $
     pragma pragmaText . inci $ do
       sep commaDel p_rdrName fnames
       breakpoint
diff --git a/src/Ormolu/Printer/Meat/ImportExport.hs b/src/Ormolu/Printer/Meat/ImportExport.hs
--- a/src/Ormolu/Printer/Meat/ImportExport.hs
+++ b/src/Ormolu/Printer/Meat/ImportExport.hs
@@ -12,8 +12,7 @@
 
 import Control.Monad
 import qualified Data.Text as T
-import GHC.Hs.Extension
-import GHC.Hs.ImpExp
+import GHC.Hs
 import GHC.LanguageExtensions.Type
 import GHC.Types.SrcLoc
 import GHC.Unit.Types
@@ -86,15 +85,15 @@
   IEVar NoExtField l1 -> do
     located l1 p_ieWrappedName
     p_comma
-  IEThingAbs NoExtField l1 -> do
+  IEThingAbs _ l1 -> do
     located l1 p_ieWrappedName
     p_comma
-  IEThingAll NoExtField l1 -> do
+  IEThingAll _ l1 -> do
     located l1 p_ieWrappedName
     space
     txt "(..)"
     p_comma
-  IEThingWith NoExtField l1 w xs _ -> sitcc $ do
+  IEThingWith _ l1 w xs -> sitcc $ do
     located l1 p_ieWrappedName
     breakIfNotDiffFriendly
     inci $ do
@@ -107,7 +106,7 @@
             let (before, after) = splitAt n names
              in before ++ [txt ".."] ++ after
     p_comma
-  IEModuleContents NoExtField l1 -> do
+  IEModuleContents _ l1 -> do
     located l1 p_hsmodName
     p_comma
   IEGroup NoExtField n str -> do
diff --git a/src/Ormolu/Printer/Meat/Module.hs b/src/Ormolu/Printer/Meat/Module.hs
--- a/src/Ormolu/Printer/Meat/Module.hs
+++ b/src/Ormolu/Printer/Meat/Module.hs
@@ -9,7 +9,7 @@
 where
 
 import Control.Monad
-import GHC.Hs
+import GHC.Hs hiding (comment)
 import GHC.Types.SrcLoc
 import Ormolu.Config
 import Ormolu.Imports (normalizeImports)
@@ -23,7 +23,8 @@
 import Ormolu.Printer.Meat.ImportExport
 import Ormolu.Printer.Meat.Pragma
 
--- | Render a module.
+-- | Render a module-like entity (either a regular module or a backpack
+-- signature).
 p_hsModule ::
   -- | Stack header
   Maybe (RealLocated Comment) ->
@@ -33,8 +34,8 @@
   HsModule ->
   R ()
 p_hsModule mstackHeader pragmas HsModule {..} = do
-  let deprecSpan = maybe [] (\(L s _) -> [s]) hsmodDeprecMessage
-      exportSpans = maybe [] (\(L s _) -> [s]) hsmodExports
+  let deprecSpan = maybe [] (pure . getLocA) hsmodDeprecMessage
+      exportSpans = maybe [] (pure . getLocA) hsmodExports
   switchLayout (deprecSpan <> exportSpans) $ do
     forM_ mstackHeader $ \(L spn comment) -> do
       spitCommentNow spn comment
@@ -71,7 +72,7 @@
       forM_ importGroup (located' p_hsmodImport)
       newline
     declNewline
-    switchLayout (getLoc <$> hsmodDecls) $ do
+    switchLayout (getLocA <$> hsmodDecls) $ do
       preserveSpacing <- getPrinterOpt poRespectful
       (if preserveSpacing then p_hsDeclsRespectGrouping else p_hsDecls) Free hsmodDecls
       newline
diff --git a/src/Ormolu/Printer/Meat/Type.hs b/src/Ormolu/Printer/Meat/Type.hs
--- a/src/Ormolu/Printer/Meat/Type.hs
+++ b/src/Ormolu/Printer/Meat/Type.hs
@@ -2,6 +2,7 @@
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE RecordWildCards #-}
+{-# LANGUAGE TypeFamilies #-}
 
 -- | Rendering of types.
 module Ormolu.Printer.Meat.Type
@@ -14,19 +15,22 @@
     p_forallBndrs,
     p_conDeclFields,
     p_lhsTypeArg,
-    tyVarsToTypes,
+    p_hsSigType,
     tyVarsToTyPats,
+    hsOuterTyVarBndrsToHsType,
+    lhsTypeToSigType,
   )
 where
 
-import Data.Data (Data)
-import GHC.Hs.Decls
-import GHC.Hs.Extension
-import GHC.Hs.Type
+import Control.Monad
+import Data.Foldable (for_)
+import GHC.Hs
 import GHC.Types.Basic hiding (isPromoted)
 import GHC.Types.Name.Reader
+import GHC.Types.SourceText
 import GHC.Types.SrcLoc
 import GHC.Types.Var
+import Ormolu.Config
 import Ormolu.Printer.Combinators
 import Ormolu.Printer.Meat.Common
 import {-# SOURCE #-} Ormolu.Printer.Meat.Declaration.Value (p_hsSplice, p_stringLit)
@@ -46,22 +50,23 @@
 
 p_hsType' :: Bool -> TypeDocStyle -> HsType GhcPs -> R ()
 p_hsType' multilineArgs docStyle = \case
-  HsForAllTy NoExtField tele t -> do
+  HsForAllTy _ tele t -> do
     case tele of
-      HsForAllInvis NoExtField bndrs -> p_forallBndrs ForAllInvis p_hsTyVarBndr bndrs
-      HsForAllVis NoExtField bndrs -> p_forallBndrs ForAllVis p_hsTyVarBndr bndrs
+      HsForAllInvis _ bndrs -> p_forallBndrs ForAllInvis p_hsTyVarBndr bndrs
+      HsForAllVis _ bndrs -> p_forallBndrs ForAllVis p_hsTyVarBndr bndrs
     interArgBreak
     p_hsTypeR (unLoc t)
-  HsQualTy NoExtField qs t -> do
-    located qs p_hsContext
-    space
-    txt "=>"
-    interArgBreak
+  HsQualTy _ qs' t -> do
+    for_ qs' $ \qs -> do
+      located qs p_hsContext
+      space
+      txt "=>"
+      interArgBreak
     case unLoc t of
       HsQualTy {} -> p_hsTypeR (unLoc t)
       HsFunTy {} -> p_hsTypeR (unLoc t)
       _ -> located t p_hsTypeR
-  HsTyVar NoExtField p n -> do
+  HsTyVar _ p n -> do
     case p of
       IsPromoted -> do
         space
@@ -71,7 +76,7 @@
           _ -> return ()
       NotPromoted -> return ()
     p_rdrName n
-  HsAppTy NoExtField f x -> do
+  HsAppTy _ f x -> do
     let -- In order to format type applications with multiple parameters
         -- nicer, traverse the AST to gather the function and all the
         -- parameters together.
@@ -80,7 +85,7 @@
             L _ (HsAppTy _ l r) -> gatherArgs l (r : knownArgs)
             _ -> (f', knownArgs)
         (func, args) = gatherArgs f [x]
-    switchLayout (getLoc f : fmap getLoc args) . sitcc $ do
+    switchLayout (getLocA f : fmap getLocA args) . sitcc $ do
       located func p_hsType
       breakpoint
       inci $
@@ -94,13 +99,13 @@
     inci $ do
       txt "@"
       located kd p_hsType
-  HsFunTy NoExtField arrow x y@(L _ y') -> do
+  HsFunTy _ arrow x y@(L _ y') -> do
     located x p_hsType
     space
     case arrow of
       HsUnrestrictedArrow _ -> txt "->"
-      HsLinearArrow _ -> txt "%1 ->"
-      HsExplicitMult _ mult -> do
+      HsLinearArrow _ _ -> txt "%1 ->"
+      HsExplicitMult _ _ mult -> do
         txt "%"
         p_hsTypeR (unLoc mult)
         space
@@ -109,40 +114,38 @@
     case y' of
       HsFunTy {} -> p_hsTypeR y'
       _ -> located y p_hsTypeR
-  HsListTy NoExtField t ->
+  HsListTy _ t ->
     located t (brackets N . p_hsType)
-  HsTupleTy NoExtField tsort xs ->
+  HsTupleTy _ tsort xs ->
     let parens' =
           case tsort of
             HsUnboxedTuple -> parensHash N
-            HsBoxedTuple -> parens N
-            HsConstraintTuple -> parens N
             HsBoxedOrConstraintTuple -> parens N
      in parens' $ sep commaDel (sitcc . located' p_hsType) xs
-  HsSumTy NoExtField xs ->
+  HsSumTy _ xs ->
     parensHash N $
       sep (txt "|" >> breakpoint) (sitcc . located' p_hsType) xs
-  HsOpTy NoExtField x op y ->
+  HsOpTy _ x op y ->
     sitcc $
       let opTree = OpBranch (tyOpTree x) op (tyOpTree y)
        in p_tyOpTree (reassociateOpTree Just opTree)
-  HsParTy NoExtField t ->
+  HsParTy _ t ->
     parens N $ sitcc $ located t p_hsType
-  HsIParamTy NoExtField n t -> sitcc $ do
+  HsIParamTy _ n t -> sitcc $ do
     located n atom
     space
     txt "::"
     breakpoint
     inci (located t p_hsType)
-  HsStarTy NoExtField _ -> txt "*"
-  HsKindSig NoExtField t k -> sitcc $ do
+  HsStarTy _ _ -> txt "*"
+  HsKindSig _ t k -> sitcc $ do
     located t p_hsType
     space
     txt "::"
     breakpoint
     inci (located k p_hsType)
-  HsSpliceTy NoExtField splice -> p_hsSplice splice
-  HsDocTy NoExtField t str ->
+  HsSpliceTy _ splice -> p_hsSplice splice
+  HsDocTy _ t str ->
     case docStyle of
       PipeStyle -> do
         p_hsDocString Pipe True str
@@ -151,7 +154,7 @@
         located t p_hsType
         newline
         p_hsDocString Caret False str
-  HsBangTy NoExtField (HsSrcBang _ u s) t -> do
+  HsBangTy _ (HsSrcBang _ u s) t -> do
     case u of
       SrcUnpack -> txt "{-# UNPACK #-}" >> space
       SrcNoUnpack -> txt "{-# NOUNPACK #-}" >> space
@@ -161,9 +164,9 @@
       SrcStrict -> txt "!"
       NoSrcStrict -> return ()
     located t p_hsType
-  HsRecTy NoExtField fields ->
+  HsRecTy _ fields ->
     p_conDeclFields fields
-  HsExplicitListTy NoExtField p xs -> do
+  HsExplicitListTy _ p xs -> do
     case p of
       IsPromoted -> txt "'"
       NotPromoted -> return ()
@@ -174,19 +177,19 @@
         (IsPromoted, L _ t : _) | isPromoted t -> space
         _ -> return ()
       sep commaDel (sitcc . located' p_hsType) xs
-  HsExplicitTupleTy NoExtField xs -> do
+  HsExplicitTupleTy _ xs -> do
     txt "'"
     parens N $ do
       case xs of
         L _ t : _ | isPromoted t -> space
         _ -> return ()
       sep commaDel (located' p_hsType) xs
-  HsTyLit NoExtField t ->
+  HsTyLit _ t ->
     case t of
       HsStrTy (SourceText s) _ -> p_stringLit s
       a -> atom a
-  HsWildCardTy NoExtField -> txt "_"
-  XHsType (NHsCoreTy t) -> atom t
+  HsWildCardTy _ -> txt "_"
+  XHsType t -> atom t
   where
     isPromoted = \case
       HsAppTy _ (L _ f) _ -> isPromoted f
@@ -229,9 +232,9 @@
 
 p_hsTyVarBndr :: IsInferredTyVarBndr flag => HsTyVarBndr flag GhcPs -> R ()
 p_hsTyVarBndr = \case
-  UserTyVar NoExtField flag x ->
+  UserTyVar _ flag x ->
     (if isInferred flag then braces N else id) $ p_rdrName x
-  KindedTyVar NoExtField flag l k -> (if isInferred flag then braces else parens) N . sitcc $ do
+  KindedTyVar _ flag l k -> (if isInferred flag then braces else parens) N . sitcc $ do
     located l atom
     space
     txt "::"
@@ -241,11 +244,11 @@
 data ForAllVisibility = ForAllInvis | ForAllVis
 
 -- | Render several @forall@-ed variables.
-p_forallBndrs :: Data a => ForAllVisibility -> (a -> R ()) -> [Located a] -> R ()
+p_forallBndrs :: ForAllVisibility -> (a -> R ()) -> [LocatedA a] -> R ()
 p_forallBndrs ForAllInvis _ [] = txt "forall."
 p_forallBndrs ForAllVis _ [] = txt "forall ->"
 p_forallBndrs vis p tyvars =
-  switchLayout (getLoc <$> tyvars) $ do
+  switchLayout (getLocA <$> tyvars) $ do
     txt "forall"
     breakpoint
     inci $ do
@@ -256,11 +259,13 @@
 
 p_conDeclFields :: [LConDeclField GhcPs] -> R ()
 p_conDeclFields xs =
-  braces N $ sep commaDel (sitcc . located' p_conDeclField) xs
+  braces N $ sep commaDel (located' p_conDeclField) xs
 
 p_conDeclField :: ConDeclField GhcPs -> R ()
 p_conDeclField ConDeclField {..} = do
-  mapM_ (p_hsDocString Pipe True) cd_fld_doc
+  commaStyle <- getPrinterOpt poCommaStyle
+  when (commaStyle == Trailing) $
+    mapM_ (p_hsDocString Pipe True) cd_fld_doc
   sitcc $
     sep
       commaDel
@@ -270,13 +275,15 @@
   txt "::"
   breakpoint
   sitcc . inci $ p_hsType (unLoc cd_fld_type)
+  when (commaStyle == Leading) $
+    mapM_ ((newline >>) . p_hsDocString Caret False) cd_fld_doc
 
-tyOpTree :: LHsType GhcPs -> OpTree (LHsType GhcPs) (Located RdrName)
-tyOpTree (L _ (HsOpTy NoExtField l op r)) =
+tyOpTree :: LHsType GhcPs -> OpTree (LHsType GhcPs) (LocatedN RdrName)
+tyOpTree (L _ (HsOpTy _ l op r)) =
   OpBranch (tyOpTree l) op (tyOpTree r)
 tyOpTree n = OpNode n
 
-p_tyOpTree :: OpTree (LHsType GhcPs) (Located RdrName) -> R ()
+p_tyOpTree :: OpTree (LHsType GhcPs) (LocatedN RdrName) -> R ()
 p_tyOpTree (OpNode n) = located n p_hsType
 p_tyOpTree (OpBranch l op r) = do
   switchLayout [opTreeLoc l] $
@@ -296,23 +303,38 @@
   -- NOTE(amesgen) is this unreachable or just not implemented?
   HsArgPar _ -> notImplemented "HsArgPar"
 
+p_hsSigType :: HsSigType GhcPs -> R ()
+p_hsSigType HsSig {..} =
+  p_hsType $ hsOuterTyVarBndrsToHsType sig_bndrs sig_body
+
 ----------------------------------------------------------------------------
 -- Conversion functions
 
-tyVarsToTypes :: LHsQTyVars GhcPs -> [LHsType GhcPs]
-tyVarsToTypes HsQTvs {..} = fmap tyVarToType <$> hsq_explicit
-
 tyVarToType :: HsTyVarBndr () GhcPs -> HsType GhcPs
 tyVarToType = \case
-  UserTyVar NoExtField () tvar -> HsTyVar NoExtField NotPromoted tvar
-  KindedTyVar NoExtField () tvar kind ->
+  UserTyVar _ () tvar -> HsTyVar EpAnnNotUsed NotPromoted tvar
+  KindedTyVar _ () tvar kind ->
     -- Note: we always add parentheses because for whatever reason GHC does
     -- not use HsParTy for left-hand sides of declarations. Please see
     -- <https://gitlab.haskell.org/ghc/ghc/issues/17404>. This is fine as
     -- long as 'tyVarToType' does not get applied to right-hand sides of
     -- declarations.
-    HsParTy NoExtField . noLoc $
-      HsKindSig NoExtField (noLoc (HsTyVar NoExtField NotPromoted tvar)) kind
+    HsParTy EpAnnNotUsed . noLocA $
+      HsKindSig EpAnnNotUsed (noLocA (HsTyVar EpAnnNotUsed NotPromoted tvar)) kind
 
 tyVarsToTyPats :: LHsQTyVars GhcPs -> HsTyPats GhcPs
 tyVarsToTyPats HsQTvs {..} = HsValArg . fmap tyVarToType <$> hsq_explicit
+
+-- could be generalized to also handle () instead of Specificity
+hsOuterTyVarBndrsToHsType ::
+  HsOuterTyVarBndrs Specificity GhcPs ->
+  LHsType GhcPs ->
+  HsType GhcPs
+hsOuterTyVarBndrsToHsType obndrs ty = case obndrs of
+  HsOuterImplicit NoExtField -> unLoc ty
+  HsOuterExplicit _ bndrs ->
+    HsForAllTy NoExtField (mkHsForAllInvisTele EpAnnNotUsed bndrs) ty
+
+lhsTypeToSigType :: LHsType GhcPs -> LHsSigType GhcPs
+lhsTypeToSigType ty =
+  reLocA . L (getLocA ty) . HsSig NoExtField (HsOuterImplicit NoExtField) $ ty
diff --git a/src/Ormolu/Printer/Operators.hs b/src/Ormolu/Printer/Operators.hs
--- a/src/Ormolu/Printer/Operators.hs
+++ b/src/Ormolu/Printer/Operators.hs
@@ -15,11 +15,12 @@
 import Data.Map.Strict (Map)
 import qualified Data.Map.Strict as M
 import Data.Maybe (fromMaybe, mapMaybe)
-import GHC.Types.Basic
+import GHC.Types.Fixity
 import GHC.Types.Name.Occurrence (occNameString)
 import GHC.Types.Name.Reader
+import GHC.Types.SourceText
 import GHC.Types.SrcLoc
-import Ormolu.Utils (unSrcSpan)
+import Ormolu.Utils
 
 -- | Intermediate representation of operator trees. It has two type
 -- parameters: @ty@ is the type of sub-expressions, while @op@ is the type
@@ -32,8 +33,8 @@
       (OpTree ty op)
 
 -- | Return combined 'SrcSpan's of all elements in this 'OpTree'.
-opTreeLoc :: OpTree (Located a) b -> SrcSpan
-opTreeLoc (OpNode (L l _)) = l
+opTreeLoc :: HasSrcSpan l => OpTree (GenLocated l a) b -> SrcSpan
+opTreeLoc (OpNode n) = getLoc' n
 opTreeLoc (OpBranch l _ r) = combineSrcSpans (opTreeLoc l) (opTreeLoc r)
 
 -- | Re-associate an 'OpTree' taking into account automagically inferred
@@ -41,12 +42,13 @@
 -- an initial 'OpTree', then re-associate it using this function before
 -- printing.
 reassociateOpTree ::
+  (HasSrcSpan l, HasSrcSpan l') =>
   -- | How to get name of an operator
   (op -> Maybe RdrName) ->
   -- | Original 'OpTree'
-  OpTree (Located ty) (Located op) ->
+  OpTree (GenLocated l ty) (GenLocated l' op) ->
   -- | Re-associated 'OpTree'
-  OpTree (Located ty) (Located op)
+  OpTree (GenLocated l ty) (GenLocated l' op)
 reassociateOpTree getOpName opTree =
   reassociateOpTreeWith
     (buildFixityMap getOpName normOpTree)
@@ -108,11 +110,12 @@
 
 -- | Build a map of inferred 'Fixity's from an 'OpTree'.
 buildFixityMap ::
-  forall ty op.
+  forall ty op l l'.
+  (HasSrcSpan l, HasSrcSpan l') =>
   -- | How to get the name of an operator
   (op -> Maybe RdrName) ->
   -- | Operator tree
-  OpTree (Located ty) (Located op) ->
+  OpTree (GenLocated l ty) (GenLocated l' op) ->
   -- | Fixity map
   Map String Fixity
 buildFixityMap getOpName opTree =
@@ -133,16 +136,16 @@
         ]
         `M.union` m
     fixity = Fixity NoSourceText
-    score :: OpTree (Located ty) (Located op) -> [(String, Score)]
+    score :: OpTree (GenLocated l ty) (GenLocated l' op) -> [(String, Score)]
     score (OpNode _) = []
     score (OpBranch l o r) = fromMaybe (score r) $ do
       -- If we fail to get any of these, 'defaultFixity' will be used by
       -- 'reassociateOpTreeWith'.
-      le <- srcSpanEndLine <$> unSrcSpan (opTreeLoc l) -- left end
-      ob <- srcSpanStartLine <$> unSrcSpan (getLoc o) -- operator begin
-      oe <- srcSpanEndLine <$> unSrcSpan (getLoc o) -- operator end
-      rb <- srcSpanStartLine <$> unSrcSpan (opTreeLoc r) -- right begin
-      oc <- srcSpanStartCol <$> unSrcSpan (getLoc o) -- operator column
+      le <- srcSpanEndLine <$> srcSpanToRealSrcSpan (opTreeLoc l) -- left end
+      ob <- srcSpanStartLine <$> srcSpanToRealSrcSpan (getLoc' o) -- operator begin
+      oe <- srcSpanEndLine <$> srcSpanToRealSrcSpan (getLoc' o) -- operator end
+      rb <- srcSpanStartLine <$> srcSpanToRealSrcSpan (opTreeLoc r) -- right begin
+      oc <- srcSpanStartCol <$> srcSpanToRealSrcSpan (getLoc' o) -- operator column
       opName <- occNameString . rdrNameOcc <$> getOpName (unLoc o)
       let s
             | le < ob = AtBeginning oc
diff --git a/src/Ormolu/Printer/SpanStream.hs b/src/Ormolu/Printer/SpanStream.hs
--- a/src/Ormolu/Printer/SpanStream.hs
+++ b/src/Ormolu/Printer/SpanStream.hs
@@ -11,9 +11,11 @@
 import Data.DList (DList)
 import qualified Data.DList as D
 import Data.Data (Data)
-import Data.Generics (everything, ext2Q)
+import Data.Generics (everything, ext1Q, ext2Q)
 import Data.List (sortOn)
+import Data.Maybe (maybeToList)
 import Data.Typeable (cast)
+import GHC.Parser.Annotation
 import GHC.Types.SrcLoc
 
 -- | A stream of 'RealSrcSpan's in ascending order. This allows us to tell
@@ -33,14 +35,15 @@
   SpanStream
     . sortOn realSrcSpanStart
     . D.toList
-    $ everything mappend (const mempty `ext2Q` queryLocated) a
+    $ everything mappend (const mempty `ext2Q` queryLocated `ext1Q` querySrcSpanAnn) a
   where
     queryLocated ::
       (Data e0) =>
       GenLocated e0 e1 ->
       DList RealSrcSpan
     queryLocated (L mspn _) =
-      case cast mspn :: Maybe SrcSpan of
-        Nothing -> mempty
-        Just (UnhelpfulSpan _) -> mempty
-        Just (RealSrcSpan spn _) -> D.singleton spn
+      maybe mempty srcSpanToRealSrcSpanDList (cast mspn :: Maybe SrcSpan)
+    querySrcSpanAnn :: SrcSpanAnn' a -> DList RealSrcSpan
+    querySrcSpanAnn = srcSpanToRealSrcSpanDList . locA
+    srcSpanToRealSrcSpanDList =
+      D.fromList . maybeToList . srcSpanToRealSrcSpan
diff --git a/src/Ormolu/Processing/Common.hs b/src/Ormolu/Processing/Common.hs
--- a/src/Ormolu/Processing/Common.hs
+++ b/src/Ormolu/Processing/Common.hs
@@ -7,7 +7,6 @@
   ( removeIndentation,
     reindent,
     linesInRegion,
-    regionInbetween,
     intSetToRegions,
   )
 where
@@ -40,20 +39,6 @@
   where
     (_, nonPrefix) = splitAt regionPrefixLength ls
     middle = take (length nonPrefix - regionSuffixLength) nonPrefix
-
--- | Get the region after the end of the first and till the end of
--- the second region.
-regionInbetween ::
-  -- | Total number of lines
-  Int ->
-  RegionDeltas ->
-  RegionDeltas ->
-  RegionDeltas
-regionInbetween total r r' =
-  RegionDeltas
-    { regionPrefixLength = total - regionSuffixLength r,
-      regionSuffixLength = total - regionPrefixLength r'
-    }
 
 -- | Convert a set of line indices into disjoint 'RegionDelta's
 intSetToRegions ::
diff --git a/src/Ormolu/Processing/Cpp.hs b/src/Ormolu/Processing/Cpp.hs
--- a/src/Ormolu/Processing/Cpp.hs
+++ b/src/Ormolu/Processing/Cpp.hs
@@ -29,25 +29,25 @@
     go _ [] = []
     go state ((line, i) : ls)
       | any for ["define ", "include ", "undef "] =
-        i : go contState ls
+          i : go contState ls
       | any for ["ifdef ", "ifndef ", "if "] =
-        let state' = case state of
-              InConditional nc -> InConditional (nc + 1)
-              _ -> InConditional 1
-         in i : go state' ls
+          let state' = case state of
+                InConditional nc -> InConditional (nc + 1)
+                _ -> InConditional 1
+           in i : go state' ls
       | for "endif" =
-        let state' = case state of
-              InConditional nc | nc > 1 -> InConditional (nc - 1)
-              _ -> Outside
-         in i : go state' ls
+          let state' = case state of
+                InConditional nc | nc > 1 -> InConditional (nc - 1)
+                _ -> Outside
+           in i : go state' ls
       | otherwise =
-        let is = case state of
-              Outside -> []
-              _ -> [i]
-            state' = case state of
-              InContinuation -> contState
-              _ -> state
-         in is <> go state' ls
+          let is = case state of
+                Outside -> []
+                _ -> [i]
+              state' = case state of
+                InContinuation -> contState
+                _ -> state
+           in is <> go state' ls
       where
         for directive = isJust $ do
           s <- dropWhile isSpace <$> L.stripPrefix "#" line
diff --git a/src/Ormolu/Processing/Preprocess.hs b/src/Ormolu/Processing/Preprocess.hs
--- a/src/Ormolu/Processing/Preprocess.hs
+++ b/src/Ormolu/Processing/Preprocess.hs
@@ -10,6 +10,7 @@
 where
 
 import Control.Monad
+import Data.Array as A
 import Data.Bifunctor (bimap)
 import Data.Char (isSpace)
 import Data.Function ((&))
@@ -76,13 +77,15 @@
       Left r | T.all isSpace r -> True
       _ -> False
 
-    rawLines = lines rawInput
+    rawLines = A.listArray (0, length rawLines' - 1) rawLines'
+      where
+        rawLines' = lines rawInput
     rawLineLength = length rawLines
 
     interleave [] bs = bs
     interleave (a : as) bs = a : interleave bs as
 
-    xs !!? i = if i >= 0 && i < length xs then Just $ xs !! i else Nothing
+    xs !!? i = if A.bounds rawLines `A.inRange` i then Just $ xs A.! i else Nothing
 
 -- | All lines we are not supposed to format, and a set of replacements
 -- for specific lines.
@@ -124,10 +127,10 @@
     go state ((line, i) : ls)
       | Just marker <- disablingMagicComment line,
         state == OrmoluEnabled =
-        ([i], [(i, marker)]) : go OrmoluDisabled ls
+          ([i], [(i, marker)]) : go OrmoluDisabled ls
       | Just marker <- enablingMagicComment line,
         state == OrmoluDisabled =
-        ([i], [(i, marker)]) : go OrmoluEnabled ls
+          ([i], [(i, marker)]) : go OrmoluEnabled ls
       | otherwise = iIfDisabled : go state ls
       where
         iIfDisabled = case state of
diff --git a/src/Ormolu/Utils.hs b/src/Ormolu/Utils.hs
--- a/src/Ormolu/Utils.hs
+++ b/src/Ormolu/Utils.hs
@@ -10,12 +10,13 @@
     notImplemented,
     showOutputable,
     splitDocString,
-    unSrcSpan,
     incSpanLine,
     separatedByBlank,
     separatedByBlankNE,
     onTheSameLine,
     groupBy',
+    HasSrcSpan (..),
+    getLoc',
   )
 where
 
@@ -25,10 +26,11 @@
 import Data.Maybe (fromMaybe)
 import Data.Text (Text)
 import qualified Data.Text as T
+import GHC.Driver.Ppr
 import GHC.DynFlags (baseDynFlags)
 import GHC.Hs
 import GHC.Types.SrcLoc
-import qualified GHC.Utils.Outputable as GHC
+import GHC.Utils.Outputable
 
 -- | Relative positions in a list.
 data RelativePos
@@ -58,8 +60,8 @@
 notImplemented msg = error $ "not implemented yet: " ++ msg
 
 -- | Pretty-print an 'GHC.Outputable' thing.
-showOutputable :: GHC.Outputable o => o -> String
-showOutputable = GHC.showSDoc baseDynFlags . GHC.ppr
+showOutputable :: Outputable o => o -> String
+showOutputable = showSDoc baseDynFlags . ppr
 
 -- | Split and normalize a doc string. The result is a list of lines that
 -- make up the comment.
@@ -84,12 +86,6 @@
         _ -> txt
     escapeCommentBraces = T.replace "{-" "{\\-" . T.replace "-}" "-\\}"
 
--- | Get 'RealSrcSpan' out of 'SrcSpan' if the span is “helpful”.
-unSrcSpan :: SrcSpan -> Maybe RealSrcSpan
-unSrcSpan = \case
-  RealSrcSpan r _ -> Just r
-  UnhelpfulSpan _ -> Nothing
-
 -- | Increment line number in a 'SrcSpan'.
 incSpanLine :: Int -> SrcSpan -> SrcSpan
 incSpanLine i = \case
@@ -108,8 +104,8 @@
 separatedByBlank :: (a -> SrcSpan) -> a -> a -> Bool
 separatedByBlank loc a b =
   fromMaybe False $ do
-    endA <- srcSpanEndLine <$> unSrcSpan (loc a)
-    startB <- srcSpanStartLine <$> unSrcSpan (loc b)
+    endA <- srcSpanEndLine <$> srcSpanToRealSrcSpan (loc a)
+    startB <- srcSpanStartLine <$> srcSpanToRealSrcSpan (loc b)
     pure (startB - endA >= 2)
 
 -- | Do two declaration groups have a blank between them?
@@ -130,3 +126,15 @@
     if x `eq` y
       then (x :| y : ys) : zs
       else pure x : (y :| ys) : zs
+
+class HasSrcSpan l where
+  loc' :: l -> SrcSpan
+
+instance HasSrcSpan SrcSpan where
+  loc' = id
+
+instance HasSrcSpan (SrcSpanAnn' ann) where
+  loc' = locA
+
+getLoc' :: HasSrcSpan l => GenLocated l a -> SrcSpan
+getLoc' = loc' . getLoc
diff --git a/src/Ormolu/Utils/Extensions.hs b/src/Ormolu/Utils/Extensions.hs
--- a/src/Ormolu/Utils/Extensions.hs
+++ b/src/Ormolu/Utils/Extensions.hs
@@ -21,6 +21,7 @@
 import Distribution.PackageDescription
 import Distribution.PackageDescription.Parsec
 import qualified Distribution.Types.CondTree as CT
+import Distribution.Utils.Path (getSymbolicPath)
 import Language.Haskell.Extension
 import Ormolu.Config
 import Ormolu.Exception
@@ -60,13 +61,12 @@
       where
         prependSrcDirs f
           | null hsSourceDirs = [f]
-          | otherwise = (</> f) <$> hsSourceDirs
+          | otherwise = (</> f) . getSymbolicPath <$> hsSourceDirs
         exts = maybe [] langExt defaultLanguage ++ fmap extToDynOption defaultExtensions
         langExt =
-          pure . DynOption . \case
-            Haskell98 -> "-XHaskell98"
-            Haskell2010 -> "-XHaskell2010"
-            UnknownLanguage lan -> "-X" ++ lan
+          pure . DynOption . ("-X" <>) . \case
+            UnknownLanguage lan -> lan
+            lan -> show lan
         extToDynOption =
           DynOption . \case
             EnableExtension e -> "-X" ++ show e
@@ -108,9 +108,9 @@
         [] -> pure Nothing
         e : es
           | takeExtension e == ".cabal" ->
-            doesFileExist (parentDir </> e) >>= \case
-              True -> pure $ Just e
-              False -> findDotCabal es
+              doesFileExist (parentDir </> e) >>= \case
+                True -> pure $ Just e
+                False -> findDotCabal es
         _ : es -> findDotCabal es
   findDotCabal dirEntries >>= \case
     Just cabalFile -> pure . Just $ parentDir </> cabalFile
diff --git a/src/Ormolu/Utils/IO.hs b/src/Ormolu/Utils/IO.hs
--- a/src/Ormolu/Utils/IO.hs
+++ b/src/Ormolu/Utils/IO.hs
@@ -3,11 +3,13 @@
 module Ormolu.Utils.IO
   ( writeFileUtf8,
     readFileUtf8,
+    getContentsUtf8,
   )
 where
 
 import Control.Exception (throwIO)
 import Control.Monad.IO.Class
+import Data.ByteString (ByteString)
 import qualified Data.ByteString as B
 import Data.Text (Text)
 import qualified Data.Text.Encoding as TE
@@ -20,4 +22,13 @@
 -- | Read an entire file strictly into a 'Text' using UTF8 and
 -- ignoring native line ending conventions.
 readFileUtf8 :: MonadIO m => FilePath -> m Text
-readFileUtf8 p = liftIO $ either throwIO pure . TE.decodeUtf8' =<< B.readFile p
+readFileUtf8 p = liftIO (B.readFile p) >>= decodeUtf8
+
+-- | Read stdin as UTF8-encoded 'Text' value.
+getContentsUtf8 :: MonadIO m => m Text
+getContentsUtf8 = liftIO B.getContents >>= decodeUtf8
+
+-- | A helper function for decoding a strict 'ByteString' into 'Text'. It is
+-- strict and fails immediately if decoding encounters a problem.
+decodeUtf8 :: MonadIO m => ByteString -> m Text
+decodeUtf8 = liftIO . either throwIO pure . TE.decodeUtf8'
diff --git a/tests/Ormolu/Diff/TextSpec.hs b/tests/Ormolu/Diff/TextSpec.hs
--- a/tests/Ormolu/Diff/TextSpec.hs
+++ b/tests/Ormolu/Diff/TextSpec.hs
@@ -25,7 +25,7 @@
     stdTest "trimming" "spaced" "spaced-v2"
     stdTest "trailing-blank-line" "no-trailing-blank-line" "with-trailing-blank-line"
 
--- | Test diff printig.
+-- | Test diff printing.
 stdTest ::
   -- | Name of the test case
   String ->
@@ -45,7 +45,7 @@
   expectedDiffText <-
     parseRelFile expectedDiffPath
       >>= readFileUtf8 . toFilePath . (diffOutputsDir </>)
-  let Just actualDiff = diffText inputA inputB "TEST"
+  Just actualDiff <- pure $ diffText inputA inputB "TEST"
   actualDiffText <- printDiff actualDiff
   actualDiffText `shouldBe` expectedDiffText
 
diff --git a/tests/Ormolu/PrinterSpec.hs b/tests/Ormolu/PrinterSpec.hs
--- a/tests/Ormolu/PrinterSpec.hs
+++ b/tests/Ormolu/PrinterSpec.hs
@@ -5,14 +5,18 @@
 import Control.Exception
 import Control.Monad
 import Data.List (isSuffixOf)
+import Data.Maybe (isJust)
 import Data.Text (Text)
 import qualified Data.Text as T
+import qualified Data.Text.IO as T
 import Ormolu
 import Ormolu.Config
 import Ormolu.Utils.IO
 import Path
 import Path.IO
+import System.Environment (lookupEnv)
 import qualified System.FilePath as F
+import System.IO.Unsafe (unsafePerformIO)
 import Test.Hspec
 
 spec :: Spec
@@ -35,22 +39,27 @@
 checkExample :: (PrinterOptsTotal, String, String) -> Path Rel File -> Spec
 checkExample (po, label, suffix) srcPath' = it (fromRelFile srcPath' ++ " works (" ++ label ++ ")") . withNiceExceptions $ do
   let srcPath = examplesDir </> srcPath'
-      cfg = defaultConfig {cfgPrinterOpts = po}
+      inputPath = fromRelFile srcPath
+      config =
+        defaultConfig
+          { cfgPrinterOpts = po,
+            cfgSourceType = detectSourceType inputPath
+          }
   expectedOutputPath <- deriveOutput suffix srcPath
   -- 1. Given input snippet of source code parse it and pretty print it.
   -- 2. Parse the result of pretty-printing again and make sure that AST
   -- is the same as AST of the original snippet. (This happens in
   -- 'ormoluFile' automatically.)
-  formatted0 <- ormoluFile cfg (fromRelFile srcPath)
+  formatted0 <- ormoluFile config inputPath
   -- 3. Check the output against expected output. Thus all tests should
   -- include two files: input and expected output.
-  -- <<< UNCOMMENT NEXT LINE TO REGENERATE OUTPUT FILES >>>
-  -- writeFile (fromRelFile expectedOutputPath) (T.unpack formatted0)
+  when shouldRegenerateOutput $
+    T.writeFile (fromRelFile expectedOutputPath) formatted0
   expected <- readFileUtf8 $ fromRelFile expectedOutputPath
   shouldMatch False formatted0 expected
   -- 4. Check that running the formatter on the output produces the same
   -- output again (the transformation is idempotent).
-  formatted1 <- ormolu cfg "<formatted>" (T.unpack formatted0)
+  formatted1 <- ormolu config "<formatted>" (T.unpack formatted0)
   shouldMatch True formatted1 formatted0
 
 -- | Build list of examples for testing.
@@ -64,13 +73,15 @@
 isInput path =
   let s = fromRelFile path
       (s', exts) = F.splitExtensions s
-   in exts == ".hs" && not ("-out" `isSuffixOf` s')
+   in exts `elem` [".hs", ".hsig"] && not ("-out" `isSuffixOf` s')
 
 -- | For given path of input file return expected name of output.
 deriveOutput :: String -> Path Rel File -> IO (Path Rel File)
 deriveOutput suffix path =
   parseRelFile $
-    F.addExtension (F.dropExtensions (fromRelFile path) ++ suffix ++ "-out") "hs"
+    F.addExtension (radical ++ suffix ++ "-out") exts
+  where
+    (radical, exts) = F.splitExtensions (fromRelFile path)
 
 -- | A version of 'shouldBe' that is specialized to comparing 'Text' values.
 -- It also prints multi-line snippets in a more readable form.
@@ -102,3 +113,8 @@
   where
     h :: OrmoluException -> IO ()
     h = expectationFailure . displayException
+
+shouldRegenerateOutput :: Bool
+shouldRegenerateOutput =
+  unsafePerformIO $ isJust <$> lookupEnv "ORMOLU_REGENERATE_EXAMPLES"
+{-# NOINLINE shouldRegenerateOutput #-}