Implement ImportQualifiedPost

25 files changed, 206 insertions, 42 deletions

diff --git a/compiler/hsSyn/HsImpExp.hs b/compiler/hsSyn/HsImpExp.hs
index d97be4bd54..1d487565e2 100644
--- a/compiler/hsSyn/HsImpExp.hs
+++ b/compiler/hsSyn/HsImpExp.hs
@@ -29,6 +29,7 @@ import SrcLoc
 import HsExtension
 
 import Data.Data
+import Data.Maybe
 
 {-
 ************************************************************************
@@ -48,6 +49,29 @@ type LImportDecl pass = Located (ImportDecl pass)
 
         -- For details on above see note [Api annotations] in ApiAnnotation
 
+-- | If/how an import is 'qualified'.
+data ImportDeclQualifiedStyle
+  = QualifiedPre  -- ^ 'qualified' appears in prepositive position.
+  | QualifiedPost -- ^ 'qualified' appears in postpositive position.
+  | NotQualified  -- ^ Not qualified.
+  deriving (Eq, Data)
+
+-- | Given two possible located 'qualified' tokens, compute a style
+-- (in a conforming Haskell program only one of the two can be not
+-- 'Nothing'). This is called from 'Parser.y'.
+importDeclQualifiedStyle :: Maybe (Located a)
+                         -> Maybe (Located a)
+                         -> ImportDeclQualifiedStyle
+importDeclQualifiedStyle mPre mPost =
+  if isJust mPre then QualifiedPre
+  else if isJust mPost then QualifiedPost else NotQualified
+
+-- | Convenience function to answer the question if an import decl. is
+-- qualified.
+isImportDeclQualified :: ImportDeclQualifiedStyle -> Bool
+isImportDeclQualified NotQualified = False
+isImportDeclQualified _ = True
+
 -- | Import Declaration
 --
 -- A single Haskell @import@ declaration.
@@ -60,7 +84,7 @@ data ImportDecl pass
       ideclPkgQual   :: Maybe StringLiteral,  -- ^ Package qualifier.
       ideclSource    :: Bool,          -- ^ True <=> {-\# SOURCE \#-} import
       ideclSafe      :: Bool,          -- ^ True => safe import
-      ideclQualified :: Bool,          -- ^ True => qualified
+      ideclQualified :: ImportDeclQualifiedStyle, -- ^ If/how the import is qualified.
       ideclImplicit  :: Bool,          -- ^ True => implicit import (of Prelude)
       ideclAs        :: Maybe (Located ModuleName),  -- ^ as Module
       ideclHiding    :: Maybe (Bool, Located [LIE pass])
@@ -96,7 +120,7 @@ simpleImportDecl mn = ImportDecl {
       ideclSource    = False,
       ideclSafe      = False,
       ideclImplicit  = False,
-      ideclQualified = False,
+      ideclQualified = NotQualified,
       ideclAs        = Nothing,
       ideclHiding    = Nothing
     }
@@ -109,7 +133,7 @@ instance (p ~ GhcPass pass,OutputableBndrId p)
                     , ideclQualified = qual, ideclImplicit = implicit
                     , ideclAs = as, ideclHiding = spec })
       = hang (hsep [text "import", ppr_imp from, pp_implicit implicit, pp_safe safe,
-                    pp_qual qual, pp_pkg pkg, ppr mod', pp_as as])
+                    pp_qual qual False, pp_pkg pkg, ppr mod', pp_qual qual True, pp_as as])
              4 (pp_spec spec)
       where
         pp_implicit False = empty
@@ -119,8 +143,11 @@ instance (p ~ GhcPass pass,OutputableBndrId p)
         pp_pkg (Just (StringLiteral st p))
           = pprWithSourceText st (doubleQuotes (ftext p))
 
-        pp_qual False   = empty
-        pp_qual True    = text "qualified"
+        pp_qual QualifiedPre False = text "qualified" -- Prepositive qualifier/prepositive position.
+        pp_qual QualifiedPost True = text "qualified" -- Postpositive qualifier/postpositive position.
+        pp_qual QualifiedPre True = empty -- Prepositive qualifier/postpositive position.
+        pp_qual QualifiedPost False = empty -- Postpositive qualifier/prepositive position.
+        pp_qual NotQualified _ = empty
 
         pp_safe False   = empty
         pp_safe True    = text "safe"
diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs
index 01750a8bd0..1a62d9b15f 100644
--- a/compiler/main/DynFlags.hs
+++ b/compiler/main/DynFlags.hs
@@ -843,6 +843,7 @@ data WarningFlag =
    | Opt_WarnImplicitKindVars             -- Since 8.6
    | Opt_WarnSpaceAfterBang
    | Opt_WarnMissingDerivingStrategies    -- Since 8.8
+   | Opt_WarnPrepositiveQualifiedModule   -- Since TBD
    deriving (Eq, Show, Enum)
 
 data Language = Haskell98 | Haskell2010
@@ -4070,7 +4071,10 @@ wWarningFlagsDeps = [
   flagSpec "star-binder"                 Opt_WarnStarBinder,
   flagSpec "star-is-type"                Opt_WarnStarIsType,
   flagSpec "missing-space-after-bang"    Opt_WarnSpaceAfterBang,
-  flagSpec "partial-fields"              Opt_WarnPartialFields ]
+  flagSpec "partial-fields"              Opt_WarnPartialFields,
+  flagSpec "prepositive-qualified-module"
+                                         Opt_WarnPrepositiveQualifiedModule
+ ]
 
 -- | These @-\<blah\>@ flags can all be reversed with @-no-\<blah\>@
 negatableFlagsDeps :: [(Deprecation, FlagSpec GeneralFlag)]
@@ -4396,6 +4400,7 @@ xFlagsDeps = [
                                               setGenDeriving,
   flagSpec "ImplicitParams"                   LangExt.ImplicitParams,
   flagSpec "ImplicitPrelude"                  LangExt.ImplicitPrelude,
+  flagSpec "ImportQualifiedPost"              LangExt.ImportQualifiedPost,
   flagSpec "ImpredicativeTypes"               LangExt.ImpredicativeTypes,
   flagSpec' "IncoherentInstances"             LangExt.IncoherentInstances
                                               setIncoherentInsts,
diff --git a/compiler/main/HeaderInfo.hs b/compiler/main/HeaderInfo.hs
index 450ac95f96..e5e5efd753 100644
--- a/compiler/main/HeaderInfo.hs
+++ b/compiler/main/HeaderInfo.hs
@@ -131,7 +131,7 @@ mkPrelImports this_mod loc implicit_prelude import_decls
                                 ideclPkgQual   = Nothing,
                                 ideclSource    = False,
                                 ideclSafe      = False,  -- Not a safe import
-                                ideclQualified = False,
+                                ideclQualified = NotQualified,
                                 ideclImplicit  = True,   -- Implicit!
                                 ideclAs        = Nothing,
                                 ideclHiding    = Nothing  }
diff --git a/compiler/main/HscStats.hs b/compiler/main/HscStats.hs
index 44edb82c5e..fdd5ee78e2 100644
--- a/compiler/main/HscStats.hs
+++ b/compiler/main/HscStats.hs
@@ -126,9 +126,10 @@ ppSourceStats short (dL->L _ (HsModule _ exports imports ldecls _ _))
     import_info _ = panic " import_info: Impossible Match"
                              -- due to #15884
 
-    safe_info = qual_info
-    qual_info False  = 0
-    qual_info True   = 1
+    safe_info False = 0
+    safe_info True = 1
+    qual_info NotQualified = 0
+    qual_info _  = 1
     as_info Nothing  = 0
     as_info (Just _) = 1
     spec_info Nothing           = (0,0,0,0,1,0,0)
diff --git a/compiler/parser/Lexer.x b/compiler/parser/Lexer.x
index 3c1ea8cc7d..edad2d90d7 100644
--- a/compiler/parser/Lexer.x
+++ b/compiler/parser/Lexer.x
@@ -2329,6 +2329,7 @@ data ExtBits
   | DoAndIfThenElseBit
   | MultiWayIfBit
   | GadtSyntaxBit
+  | ImportQualifiedPostBit
 
   -- Flags that are updated once parsing starts
   | InRulePragBit
@@ -2415,6 +2416,7 @@ mkParserFlags' warningFlags extensionFlags thisPackage
       .|. DoAndIfThenElseBit          `xoptBit` LangExt.DoAndIfThenElse
       .|. MultiWayIfBit               `xoptBit` LangExt.MultiWayIf
       .|. GadtSyntaxBit               `xoptBit` LangExt.GADTSyntax
+      .|. ImportQualifiedPostBit      `xoptBit` LangExt.ImportQualifiedPost
     optBits =
           HaddockBit        `setBitIf` isHaddock
       .|. RawTokenStreamBit `setBitIf` rawTokStream
diff --git a/compiler/parser/Parser.y b/compiler/parser/Parser.y
index e6f639edb3..c2dae02afc 100644
--- a/compiler/parser/Parser.y
+++ b/compiler/parser/Parser.y
@@ -39,6 +39,7 @@ module Parser (parseModule, parseSignature, parseImport, parseStatement, parseBa
 import Control.Monad    ( unless, liftM, when, (<=<) )
 import GHC.Exts
 import Data.Char
+import Data.Maybe       ( maybeToList )
 import Control.Monad    ( mplus )
 import Control.Applicative ((<$))
 
@@ -955,17 +956,22 @@ importdecls_semi
         | {- empty -}           { [] }
 
 importdecl :: { LImportDecl GhcPs }
-        : 'import' maybe_src maybe_safe optqualified maybe_pkg modid maybeas maybeimpspec
-                {% ams (cL (comb4 $1 $6 (snd $7) $8) $
-                  ImportDecl { ideclExt = noExt
-                             , ideclSourceSrc = snd $ fst $2
-                             , ideclName = $6, ideclPkgQual = snd $5
-                             , ideclSource = snd $2, ideclSafe = snd $3
-                             , ideclQualified = snd $4, ideclImplicit = False
-                             , ideclAs = unLoc (snd $7)
-                             , ideclHiding = unLoc $8 })
-                   ((mj AnnImport $1 : (fst $ fst $2) ++ fst $3 ++ fst $4
-                                    ++ fst $5 ++ fst $7)) }
+        : 'import' maybe_src maybe_safe optqualified maybe_pkg modid optqualified maybeas maybeimpspec
+                {% do {
+                  ; checkImportDecl $4 $7
+                  ; ams (cL (comb4 $1 $6 (snd $8) $9) $
+                      ImportDecl { ideclExt = noExt
+                                  , ideclSourceSrc = snd $ fst $2
+                                  , ideclName = $6, ideclPkgQual = snd $5
+                                  , ideclSource = snd $2, ideclSafe = snd $3
+                                  , ideclQualified = importDeclQualifiedStyle $4 $7
+                                  , ideclImplicit = False
+                                  , ideclAs = unLoc (snd $8)
+                                  , ideclHiding = unLoc $9 })
+                         ((mj AnnImport $1 : fst (fst $2) ++ fst $3 ++ fmap (mj AnnQualified) (maybeToList $4)
+                                          ++ fst $5 ++ fmap (mj AnnQualified) (maybeToList $7) ++ fst $8))
+                  }
+                }
 
 maybe_src :: { (([AddAnn],SourceText),IsBootInterface) }
         : '{-# SOURCE' '#-}'        { (([mo $1,mc $2],getSOURCE_PRAGs $1)
@@ -986,9 +992,9 @@ maybe_pkg :: { ([AddAnn],Maybe StringLiteral) }
                         ; return ([mj AnnPackageName $1], Just (StringLiteral (getSTRINGs $1) pkgFS)) } }
         | {- empty -}                           { ([],Nothing) }
 
-optqualified :: { ([AddAnn],Bool) }
-        : 'qualified'                           { ([mj AnnQualified $1],True)  }
-        | {- empty -}                           { ([],False) }
+optqualified :: { Maybe (Located Token) }
+        : 'qualified'                           { Just $1 }
+        | {- empty -}                           { Nothing }
 
 maybeas :: { ([AddAnn],Located (Maybe (Located ModuleName))) }
         : 'as' modid                           { ([mj AnnAs $1]
diff --git a/compiler/parser/RdrHsSyn.hs b/compiler/parser/RdrHsSyn.hs
index 156931dc9f..490fed0384 100644
--- a/compiler/parser/RdrHsSyn.hs
+++ b/compiler/parser/RdrHsSyn.hs
@@ -49,6 +49,7 @@ module   RdrHsSyn (
 
         -- Bunch of functions in the parser monad for
         -- checking and constructing values
+        checkImportDecl,
         checkExpBlockArguments,
         checkPrecP,           -- Int -> P Int
         checkContext,         -- HsType -> P HsContext
@@ -81,7 +82,10 @@ module   RdrHsSyn (
 
         -- Warnings and errors
         warnStarIsType,
+        warnPrepositiveQualifiedModule,
         failOpFewArgs,
+        failOpNotEnabledImportQualifiedPost,
+        failOpImportQualifiedTwice,
 
         SumOrTuple (..),
 
@@ -1051,6 +1055,31 @@ checkNoDocs msg ty = go ty
                                   , text "on", msg, quotes (ppr t) ]
     go _ = pure ()
 
+checkImportDecl :: Maybe (Located Token)
+                -> Maybe (Located Token)
+                -> P ()
+checkImportDecl mPre mPost = do
+  let whenJust mg f = maybe (pure ()) f mg
+
+  importQualifiedPostEnabled <- getBit ImportQualifiedPostBit
+
+  -- Error if 'qualified' found in postpostive position and
+  -- 'ImportQualifiedPost' is not in effect.
+  whenJust mPost $ \post ->
+    when (not importQualifiedPostEnabled) $
+      failOpNotEnabledImportQualifiedPost (getLoc post)
+
+  -- Error if 'qualified' occurs in both pre and postpositive
+  -- positions.
+  whenJust mPost $ \post ->
+    when (isJust mPre) $
+      failOpImportQualifiedTwice (getLoc post)
+
+  -- Warn if 'qualified' found in prepositive position and
+  -- 'Opt_WarnPrepositiveQualifiedModule' is enabled.
+  whenJust mPre $ \pre ->
+    warnPrepositiveQualifiedModule (getLoc pre)
+
 -- -------------------------------------------------------------------------
 -- Checking Patterns.
 
@@ -2945,6 +2974,27 @@ isImpExpQcWildcard _                = False
 -----------------------------------------------------------------------------
 -- Warnings and failures
 
+warnPrepositiveQualifiedModule :: SrcSpan -> P ()
+warnPrepositiveQualifiedModule span =
+  addWarning Opt_WarnPrepositiveQualifiedModule span msg
+  where
+    msg = text "Found" <+> quotes (text "qualified")
+           <+> text "in prepositive position"
+       $$ text "Suggested fix: place " <+> quotes (text "qualified")
+           <+> text "after the module name instead."
+
+failOpNotEnabledImportQualifiedPost :: SrcSpan -> P ()
+failOpNotEnabledImportQualifiedPost loc = addError loc msg
+  where
+    msg = text "Found" <+> quotes (text "qualified")
+          <+> text "in postpositive position. "
+      $$ text "To allow this, enable language extension 'ImportQualifiedPost'"
+
+failOpImportQualifiedTwice :: SrcSpan -> P ()
+failOpImportQualifiedTwice loc = addError loc msg
+  where
+    msg = text "Multiple occurences of 'qualified'"
+
 warnStarIsType :: SrcSpan -> P ()
 warnStarIsType span = addWarning Opt_WarnStarIsType span msg
   where
diff --git a/compiler/rename/RnNames.hs b/compiler/rename/RnNames.hs
index 7c0c6759ea..9a69423209 100644
--- a/compiler/rename/RnNames.hs
+++ b/compiler/rename/RnNames.hs
@@ -267,7 +267,7 @@ rnImportDecl this_mod
                                      , ideclName = loc_imp_mod_name
                                      , ideclPkgQual = mb_pkg
                                      , ideclSource = want_boot, ideclSafe = mod_safe
-                                     , ideclQualified = qual_only, ideclImplicit = implicit
+                                     , ideclQualified = qual_style, ideclImplicit = implicit
                                      , ideclAs = as_mod, ideclHiding = imp_details }))
   = setSrcSpan loc $ do
 
@@ -275,6 +275,8 @@ rnImportDecl this_mod
         pkg_imports <- xoptM LangExt.PackageImports
         when (not pkg_imports) $ addErr packageImportErr
 
+    let qual_only = isImportDeclQualified qual_style
+
     -- If there's an error in loadInterface, (e.g. interface
     -- file not found) we get lots of spurious errors from 'filterImports'
     let imp_mod_name = unLoc loc_imp_mod_name
@@ -1470,8 +1472,8 @@ warnUnusedImport flag fld_env (L loc decl, used, unused)
                , text "from module" <+> quotes pp_mod <+> is_redundant]
     pp_herald  = text "The" <+> pp_qual <+> text "import of"
     pp_qual
-      | ideclQualified decl = text "qualified"
-      | otherwise           = Outputable.empty
+      | isImportDeclQualified (ideclQualified decl)= text "qualified"
+      | otherwise                                  = Outputable.empty
     pp_mod       = ppr (unLoc (ideclName decl))
     is_redundant = text "is redundant"
 
diff --git a/compiler/typecheck/TcRnDriver.hs b/compiler/typecheck/TcRnDriver.hs
index 00765b6a2f..e3869d2711 100644
--- a/compiler/typecheck/TcRnDriver.hs
+++ b/compiler/typecheck/TcRnDriver.hs
@@ -1567,7 +1567,7 @@ tcPreludeClashWarn warnFlag name = do
 
         -- Unqualified import?
         isUnqualified :: ImportDecl GhcRn -> Bool
-        isUnqualified = not . ideclQualified
+        isUnqualified = not . isImportDeclQualified . ideclQualified
 
         -- List of explicitly imported (or hidden) Names from a single import.
         --   Nothing -> No explicit imports
diff --git a/docs/users_guide/glasgow_exts.rst b/docs/users_guide/glasgow_exts.rst
index 6d09b44cb7..5fef204831 100644
--- a/docs/users_guide/glasgow_exts.rst
+++ b/docs/users_guide/glasgow_exts.rst
@@ -2109,6 +2109,38 @@ data constructor in an import or export list with the keyword
 ``pattern``, to allow the import or export of a data constructor without
 its parent type constructor (see :ref:`patsyn-impexp`).
 
+.. _importqualifiedpost:
+
+Writing qualified in postpositive position
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. extension:: ImportQualifiedPost
+    :shortdesc: ``ImportQualifiedPost`` allows the syntax ``import M qualified``
+
+    :since: 8.10.1
+
+    ``ImportQualifiedPost`` allows the syntax ``import M qualified``, that is, to annotate a module as qualified by writing ``qualified`` after the module name.
+
+To import a qualified module usually you must specify ``qualified`` in prepositive position : ``import qualified M``. This often leads to a "hanging indent" (which is automatically inserted by some autoformatters and common in many code bases. For example:
+
+.. code-block::  none
+
+ import qualified A
+ import           B
+ import           C
+
+The ``ImportQualifiedPost`` extension allows ``qualified`` to appear in postpositive position : ``import M qualified``. With this extension enabled, one can write:
+
+.. code-block:: none
+
+   import A qualified
+   import B
+   import C
+
+It is an error if ``qualified`` appears in both pre and postpositive positions.
+
+The warning ``-Wprepositive-qualified-syntax`` (off by default) reports on any occurrences of imports annotated ``qualified`` using prepositive syntax.
+
 .. _block-arguments:
 
 More liberal syntax for function arguments
diff --git a/ghc/GHCi/UI.hs b/ghc/GHCi/UI.hs
index 383b7fe302..aeb8067bcc 100644
--- a/ghc/GHCi/UI.hs
+++ b/ghc/GHCi/UI.hs
@@ -2649,7 +2649,7 @@ iiSubsumes (IIModule m1) (IIModule m2) = m1==m2
 iiSubsumes (IIDecl d1) (IIDecl d2)      -- A bit crude
   =  unLoc (ideclName d1) == unLoc (ideclName d2)
      && ideclAs d1 == ideclAs d2
-     && (not (ideclQualified d1) || ideclQualified d2)
+     && (not (isImportDeclQualified (ideclQualified d1)) || isImportDeclQualified (ideclQualified d2))
      && (ideclHiding d1 `hidingSubsumes` ideclHiding d2)
   where
      _                    `hidingSubsumes` Just (False,L _ []) = True
diff --git a/libraries/ghc-boot-th/GHC/LanguageExtensions/Type.hs b/libraries/ghc-boot-th/GHC/LanguageExtensions/Type.hs
index 11460a1f86..565187be59 100644
--- a/libraries/ghc-boot-th/GHC/LanguageExtensions/Type.hs
+++ b/libraries/ghc-boot-th/GHC/LanguageExtensions/Type.hs
@@ -139,4 +139,5 @@ data Extension
    | NumericUnderscores
    | QuantifiedConstraints
    | StarIsType
+   | ImportQualifiedPost
    deriving (Eq, Enum, Show, Generic, Bounded)
diff --git a/testsuite/tests/driver/T4437.hs b/testsuite/tests/driver/T4437.hs
index 5ae423086a..2f28c05ec2 100644
--- a/testsuite/tests/driver/T4437.hs
+++ b/testsuite/tests/driver/T4437.hs
@@ -40,7 +40,8 @@ expectedGhcOnlyExtensions = ["RelaxedLayout",
                              "AlternativeLayoutRule",
                              "AlternativeLayoutRuleTransitional",
                              "EmptyDataDeriving",
-                             "GeneralisedNewtypeDeriving"]
+                             "GeneralisedNewtypeDeriving",
+                             "ImportQualifiedPost"]
 
 expectedCabalOnlyExtensions :: [String]
 expectedCabalOnlyExtensions = ["Generics",
diff --git a/testsuite/tests/module/all.T b/testsuite/tests/module/all.T
index 6ff69b0758..2a26edb6e1 100644
--- a/testsuite/tests/module/all.T
+++ b/testsuite/tests/module/all.T
@@ -263,6 +263,12 @@ test('mod179', [extra_files(['Mod179_A.hs'])], multimod_compile, ['mod179', '-v0
 
 test('mod180', [extra_files(['Mod180_A.hs', 'Mod180_B.hs'])], multimod_compile_fail, ['mod180', '-v0'])
 
+# Tests for 'ImportQualifiedPost'
+test('mod181', normal, compile, [''])
+test('mod182', normal, compile_fail, [''])
+test('mod183', normal, compile_fail, [''])
+test('mod184', normal, compile, ['-Wprepositive-qualified-module'])
+
 test('T1148', normal, compile, [''])
 test('T1074', normal, compile, [''])
 test('T1074a', normal, compile, [''])
diff --git a/testsuite/tests/module/mod181.hs b/testsuite/tests/module/mod181.hs
new file mode 100644
index 0000000000..df8b8d0aa4
--- /dev/null
+++ b/testsuite/tests/module/mod181.hs
@@ -0,0 +1,8 @@
+{-# LANGUAGE ImportQualifiedPost #-}
+
+-- If 'ImportQualifiedPost' is enabled 'qualified' can appear in
+-- postpositive position.
+
+import Prelude qualified
+
+main = Prelude.undefined
diff --git a/testsuite/tests/module/mod182.hs b/testsuite/tests/module/mod182.hs
new file mode 100644
index 0000000000..379fb3849f
--- /dev/null
+++ b/testsuite/tests/module/mod182.hs
@@ -0,0 +1,7 @@
+
+-- If 'ImportQualifiedPost' is not enabled 'qualified' can not appear in
+-- postpositive position.
+
+import Prelude qualified
+
+main = Prelude.undefined
diff --git a/testsuite/tests/module/mod182.stderr b/testsuite/tests/module/mod182.stderr
new file mode 100644
index 0000000000..2909298220
--- /dev/null
+++ b/testsuite/tests/module/mod182.stderr
@@ -0,0 +1,3 @@
+mod182.hs:5:16: error:
+    Found ‘qualified’ in postpositive position.
+    To allow this, enable language extension 'ImportQualifiedPost'
diff --git a/testsuite/tests/module/mod183.hs b/testsuite/tests/module/mod183.hs
new file mode 100644
index 0000000000..37d627645c
--- /dev/null
+++ b/testsuite/tests/module/mod183.hs
@@ -0,0 +1,7 @@
+{-# LANGUAGE ImportQualifiedPost #-}
+
+-- 'qualified' can not appear in both pre and postpositive positions.
+
+import qualified Prelude qualified
+
+main = Prelude.undefined
diff --git a/testsuite/tests/module/mod183.stderr b/testsuite/tests/module/mod183.stderr
new file mode 100644
index 0000000000..cf7fdf4fa0
--- /dev/null
+++ b/testsuite/tests/module/mod183.stderr
@@ -0,0 +1 @@
+mod183.hs:5:26: Multiple occurences of 'qualified'
diff --git a/testsuite/tests/module/mod184.hs b/testsuite/tests/module/mod184.hs
new file mode 100644
index 0000000000..7ccc78eafb
--- /dev/null
+++ b/testsuite/tests/module/mod184.hs
@@ -0,0 +1,8 @@
+{-# LANGUAGE ImportQualifiedPost #-}
+
+-- With '-Wprepositive-qualified-module', a prepositive qualified
+-- import should warn.
+
+import qualified Prelude
+
+main = Prelude.undefined
diff --git a/testsuite/tests/module/mod184.stderr b/testsuite/tests/module/mod184.stderr
new file mode 100644
index 0000000000..65e8ff2aaa
--- /dev/null
+++ b/testsuite/tests/module/mod184.stderr
@@ -0,0 +1,3 @@
+mod184.hs:6:8: warning: [-Wprepositive-qualified-module]
+    Found ‘qualified’ in prepositive position
+    Suggested fix: place  ‘qualified’ after the module name instead.
diff --git a/testsuite/tests/parser/should_compile/DumpParsedAst.stderr b/testsuite/tests/parser/should_compile/DumpParsedAst.stderr
index 5c8bb34e50..d290e61da1 100644
--- a/testsuite/tests/parser/should_compile/DumpParsedAst.stderr
+++ b/testsuite/tests/parser/should_compile/DumpParsedAst.stderr
@@ -16,7 +16,7 @@
      (Nothing)
      (False)
      (False)
-     (False)
+     (NotQualified)
      (False)
      (Nothing)
      (Nothing)))]
@@ -458,5 +458,3 @@
       [])))]
   (Nothing)
   (Nothing)))
-
-
diff --git a/testsuite/tests/parser/should_compile/DumpRenamedAst.stderr b/testsuite/tests/parser/should_compile/DumpRenamedAst.stderr
index 8dd85edcd6..48b880b16d 100644
--- a/testsuite/tests/parser/should_compile/DumpRenamedAst.stderr
+++ b/testsuite/tests/parser/should_compile/DumpRenamedAst.stderr
@@ -642,7 +642,7 @@
      (Nothing)
      (False)
      (False)
-     (False)
+     (NotQualified)
      (True)
      (Nothing)
      (Nothing)))
@@ -655,7 +655,7 @@
      (Nothing)
      (False)
      (False)
-     (False)
+     (NotQualified)
      (False)
      (Nothing)
      (Nothing)))
@@ -668,7 +668,7 @@
      (Nothing)
      (False)
      (False)
-     (False)
+     (NotQualified)
      (False)
      (Nothing)
      (Just
@@ -684,5 +684,3 @@
               {Name: GHC.Types.Type})))))])))))]
   (Nothing)
   (Nothing)))
-
-
diff --git a/testsuite/tests/parser/should_compile/KindSigs.stderr b/testsuite/tests/parser/should_compile/KindSigs.stderr
index 8ea6ec5322..6c7ef797a1 100644
--- a/testsuite/tests/parser/should_compile/KindSigs.stderr
+++ b/testsuite/tests/parser/should_compile/KindSigs.stderr
@@ -16,7 +16,7 @@
      (Nothing)
      (False)
      (False)
-     (False)
+     (NotQualified)
      (False)
      (Nothing)
      (Nothing)))]
diff --git a/testsuite/tests/parser/should_compile/T14189.stderr b/testsuite/tests/parser/should_compile/T14189.stderr
index dd8df9dc04..e405262c5c 100644
--- a/testsuite/tests/parser/should_compile/T14189.stderr
+++ b/testsuite/tests/parser/should_compile/T14189.stderr
@@ -109,7 +109,7 @@
      (Nothing)
      (False)
      (False)
-     (False)
+     (NotQualified)
      (True)
      (Nothing)
      (Nothing)))]
@@ -141,5 +141,3 @@
          (False)
          {Name: T14189.f})])])])
   (Nothing)))
-
-