Fix bug with postqualified imports and qualifiedStyle=unrestricted (#…

…1498)

data/import_style.yaml

@@ -4,3 +4,5 @@
   - {name: HypotheticalModule3, importStyle: qualified}
   - {name: 'HypotheticalModule3.*', importStyle: unqualified}
   - {name: 'HypotheticalModule3.OtherSubModule', importStyle: unrestricted, qualifiedStyle: post}
+  - {name: HypotheticalModule4, importStyle: qualified, as: HM4, asRequired: true}
+  - {name: HypotheticalModule5, importStyle: qualified, qualifiedStyle: post}

hlint.cabal

@@ -81,16 +81,16 @@ library
         deriving-aeson >= 0.2,
         filepattern >= 0.1.1
 
-    if !flag(ghc-lib) && impl(ghc >= 9.6.1) && impl(ghc < 9.7.0)
+    if !flag(ghc-lib) && impl(ghc >= 9.8.1) && impl(ghc < 9.9.0)
       build-depends:
-        ghc == 9.6.*,
+        ghc == 9.8.*,
         ghc-boot-th,
         ghc-boot
     else
       build-depends:
-          ghc-lib-parser == 9.6.*
+          ghc-lib-parser == 9.8.*
     build-depends:
-        ghc-lib-parser-ex >= 9.6.0.2 && < 9.6.1
+        ghc-lib-parser-ex >= 9.8.0.0 && < 9.8.1
 
     if flag(gpl)
         build-depends: hscolour >= 1.21

src/Config/Yaml.hs

@@ -163,7 +163,7 @@ parseFail (Val focus path) msg = fail $
     -- aim to show a smallish but relevant context
     dotDot (fromMaybe (encode focus) $ listToMaybe $ dropWhile (\x -> BS.length x > 250) $ map encode contexts)
     where
-        (steps, contexts) = unzip $ reverse path
+        (steps, contexts) = Prelude.unzip $ reverse path
         dotDot x = let (a,b) = BS.splitAt 250 x in BS.unpack a ++ (if BS.null b then "" else "...")
 
 parseArray :: Val -> Parser [Val]

src/GHC/Util/FreeVars.hs

@@ -122,8 +122,8 @@ instance FreeVars (LocatedA (HsExpr GhcPs)) where
   freeVars (L _ (RecordCon _ _ (HsRecFields flds _))) = Set.unions $ map freeVars flds -- Record construction.
   freeVars (L _ (RecordUpd _ e flds)) =
     case flds of
-      Left fs -> Set.unions $ freeVars e : map freeVars fs
-      Right ps -> Set.unions $ freeVars e : map freeVars ps
+      RegularRecUpdFields _ fs -> Set.unions $ freeVars e : map freeVars fs
+      OverloadedRecUpdFields _ ps -> Set.unions $ freeVars e : map freeVars ps
   freeVars (L _ (HsMultiIf _ grhss)) = free (allVars grhss) -- Multi-way if.
   freeVars (L _ (HsTypedBracket _ e)) = freeVars e
   freeVars (L _ (HsUntypedBracket _ (ExpBr _ e))) = freeVars e
@@ -174,7 +174,7 @@ instance FreeVars (LocatedA (HsFieldBind (LocatedAn NoEpAnns (FieldOcc GhcPs)) (
    freeVars o@(L _ (HsFieldBind _ _ x _)) = freeVars x
 
 instance FreeVars (LocatedA (HsFieldBind (LocatedAn NoEpAnns (AmbiguousFieldOcc GhcPs)) (LocatedA (HsExpr GhcPs)))) where
-  freeVars (L _ (HsFieldBind _ x _ True)) = Set.singleton $ rdrNameOcc $ rdrNameAmbiguousFieldOcc $ unLoc x -- a pun
+  freeVars (L _ (HsFieldBind _ x _ True)) = Set.singleton $ rdrNameOcc $ ambiguousFieldOccRdrName $ unLoc x -- a pun
   freeVars (L _ (HsFieldBind _ _ x _)) = freeVars x
 
 instance FreeVars (LocatedA (HsFieldBind (LocatedAn NoEpAnns (FieldLabelStrings GhcPs)) (LocatedA (HsExpr GhcPs)))) where

src/GHC/Util/HsExpr.hs

@@ -58,7 +58,7 @@ dotApps (x : xs) = dotApp x (dotApps xs)
 
 -- | @lambda [p0, p1..pn] body@ makes @\p1 p1 .. pn -> body@
 lambda :: [LPat GhcPs] -> LHsExpr GhcPs -> LHsExpr GhcPs
-lambda vs body = noLocA $ HsLam noExtField (MG Generated (noLocA [noLocA $ Match EpAnnNotUsed LambdaExpr vs (GRHSs emptyComments [noLocA $ GRHS EpAnnNotUsed [] body] (EmptyLocalBinds noExtField))]))
+lambda vs body = noLocA $ HsLam noExtField (MG (Generated DoPmc) (noLocA [noLocA $ Match EpAnnNotUsed LambdaExpr vs (GRHSs emptyComments [noLocA $ GRHS EpAnnNotUsed [] body] (EmptyLocalBinds noExtField))]))
 
 -- | 'paren e' wraps 'e' in parens if 'e' is non-atomic.
 paren :: LHsExpr GhcPs -> LHsExpr GhcPs
@@ -242,7 +242,7 @@ niceLambdaR ss e =
   let grhs = noLocA $ GRHS EpAnnNotUsed [] e :: LGRHS GhcPs (LHsExpr GhcPs)
       grhss = GRHSs {grhssExt = emptyComments, grhssGRHSs=[grhs], grhssLocalBinds=EmptyLocalBinds noExtField}
       match = noLocA $ Match {m_ext=EpAnnNotUsed, m_ctxt=LambdaExpr, m_pats=map strToPat ss, m_grhss=grhss} :: LMatch GhcPs (LHsExpr GhcPs)
-      matchGroup = MG {mg_ext=Generated, mg_alts=noLocA [match]}
+      matchGroup = MG {mg_ext=Generated DoPmc, mg_alts=noLocA [match]}
   in (noLocA $ HsLam noExtField matchGroup, const [])
 
 
@@ -252,7 +252,7 @@ replaceBranches :: LHsExpr GhcPs -> ([LHsExpr GhcPs], [LHsExpr GhcPs] -> LHsExpr
 replaceBranches (L l (HsIf _ a b c)) = ([b, c], \[b, c] -> L l (HsIf EpAnnNotUsed a b c))
 
 replaceBranches (L s (HsCase _ a (MG FromSource (L l bs)))) =
-  (concatMap f bs, L s . HsCase EpAnnNotUsed a . MG Generated . L l . g bs)
+  (concatMap f bs, L s . HsCase EpAnnNotUsed a . MG (Generated DoPmc). L l . g bs)
   where
     f :: LMatch GhcPs (LHsExpr GhcPs) -> [LHsExpr GhcPs]
     f (L _ (Match _ CaseAlt _ (GRHSs _ xs _))) = [x | (L _ (GRHS _ _ x)) <- xs]

src/Hint/Export.hs

@@ -23,7 +23,7 @@ import GHC.Types.Name.Reader
 exportHint :: ModuHint
 exportHint _ (ModuleEx (L s m@HsModule {hsmodName = Just name, hsmodExports = exports}) )
   | Nothing <- exports =
-      let r = o{ hsmodExports = Just (noLocA [noLocA (IEModuleContents EpAnnNotUsed name)] )} in
+      let r = o{ hsmodExports = Just (noLocA [noLocA (IEModuleContents (Nothing, EpAnnNotUsed) name)] )} in
       [(ignore "Use module export list" (L s o) (noLoc r) []){ideaNote = [Note "an explicit list is usually better"]}]
   | Just (L _ xs) <- exports
   , mods <- [x | x <- xs, isMod x]
@@ -32,7 +32,7 @@ exportHint _ (ModuleEx (L s m@HsModule {hsmodName = Just name, hsmodExports = ex
   , exports' <- [x | x <- xs, not (matchesModName modName x)]
   , modName `elem` names =
       let dots = mkRdrUnqual (mkVarOcc " ... ")
-          r = o{ hsmodExports = Just (noLocA (noLocA (IEVar noExtField (noLocA (IEName noExtField (noLocA dots)))) : exports') )}
+          r = o{ hsmodExports = Just (noLocA (noLocA (IEVar Nothing (noLocA (IEName noExtField (noLocA dots)))) : exports') )}
       in
         [ignore "Use explicit module export list" (L s o) (noLoc r) []]
       where

src/Hint/Extensions.hs

@@ -274,6 +274,7 @@ import Refact.Types
 import Data.Set qualified as Set
 import Data.Map qualified as Map
 
+import GHC.Data.FastString
 import GHC.Types.SrcLoc
 import GHC.Types.SourceText
 import GHC.Hs
@@ -492,8 +493,8 @@ used MultiWayIf = hasS isMultiIf
 used NumericUnderscores = hasS f
   where
     f :: OverLitVal -> Bool
-    f (HsIntegral (IL (SourceText t) _ _)) = '_' `elem` t
-    f (HsFractional (FL (SourceText t) _ _ _ _)) = '_' `elem` t
+    f (HsIntegral (IL (SourceText t) _ _)) = '_' `elem` unpackFS t
+    f (HsFractional (FL (SourceText t) _ _ _ _)) = '_' `elem` unpackFS t
     f _ = False
 
 used LambdaCase = hasS isLCase

src/Hint/Lambda.hs

@@ -170,7 +170,7 @@ lambdaBind
     where
           reform :: [LPat GhcPs] -> LHsExpr GhcPs -> Located (HsDecl GhcPs)
           reform ps b = L (combineSrcSpans (locA loc1) (locA loc2)) $ ValD noExtField $
-             origBind {fun_matches = MG Generated (noLocA [noLocA $ Match EpAnnNotUsed ctxt ps $ GRHSs emptyComments [noLocA $ GRHS EpAnnNotUsed [] b] $ EmptyLocalBinds noExtField])}
+             origBind {fun_matches = MG (Generated DoPmc) (noLocA [noLocA $ Match EpAnnNotUsed ctxt ps $ GRHSs emptyComments [noLocA $ GRHS EpAnnNotUsed [] b] $ EmptyLocalBinds noExtField])}
 
           mkSubtsAndTpl newPats newBody = (sub, tpl)
             where

src/Hint/ListRec.hs

@@ -176,7 +176,7 @@ findCase x = do
       gRHS e = noLocA $ GRHS EpAnnNotUsed [] e :: LGRHS GhcPs (LHsExpr GhcPs) -- Guarded rhs.
       gRHSSs e = GRHSs emptyComments [gRHS e] emptyLocalBinds -- Guarded rhs set.
       match e = Match{m_ext=EpAnnNotUsed,m_pats=ps12, m_grhss=gRHSSs e, ..} -- Match.
-      matchGroup e = MG{mg_alts=noLocA [noLocA $ match e], mg_ext=Generated, ..} -- Match group.
+      matchGroup e = MG{mg_alts=noLocA [noLocA $ match e], mg_ext=Generated DoPmc, ..} -- Match group.
       funBind e = FunBind {fun_matches=matchGroup e, ..} :: HsBindLR GhcPs GhcPs -- Fun bind.
 
   pure (ListCase ps b1 (x, xs, b2), noLocA . ValD noExtField . funBind)

src/Hint/Monad.hs

@@ -372,7 +372,7 @@ monadLet xs = mapMaybe mkLet xs
             grhs = noLocA (GRHS EpAnnNotUsed [] rhs)
             grhss = GRHSs emptyComments [grhs] (EmptyLocalBinds noExtField)
             match = noLocA $ Match EpAnnNotUsed (FunRhs p Prefix NoSrcStrict) [] grhss
-            fb = noLocA $ FunBind noExtField p (MG Generated (noLocA [match]))
+            fb = noLocA $ FunBind noExtField p (MG (Generated DoPmc) (noLocA [match]))
             binds = unitBag fb
             valBinds = ValBinds NoAnnSortKey binds []
             localBinds = HsValBinds EpAnnNotUsed valBinds

src/Hint/Naming.hs

@@ -102,7 +102,7 @@ shortenLGRHS (L locGRHS (GRHS ttg0 guards (L locExpr _))) =
     L locGRHS (GRHS ttg0 guards (L locExpr dots))
     where
         dots :: HsExpr GhcPs
-        dots = HsLit EpAnnNotUsed (HsString (SourceText "...") (mkFastString "..."))
+        dots = HsLit EpAnnNotUsed (HsString (SourceText (fsLit "...")) (fsLit "..."))
 
 getNames :: LHsDecl GhcPs -> [String]
 getNames decl = maybeToList (declName decl) ++ getConstructorNames (unLoc decl)

src/Hint/NumLiteral.hs

@@ -22,6 +22,7 @@
 module Hint.NumLiteral (numLiteralHint) where
 
 import GHC.Hs
+import GHC.Data.FastString
 import GHC.LanguageExtensions.Type (Extension (..))
 import GHC.Types.SrcLoc
 import GHC.Types.SourceText
@@ -49,18 +50,18 @@ numLiteralHint _ modu =
 
 suggestUnderscore :: LHsExpr GhcPs -> [Idea]
 suggestUnderscore x@(L _ (HsOverLit _ ol@(OverLit _ (HsIntegral intLit@(IL (SourceText srcTxt) _ _))))) =
-  [ suggest "Use underscore" (reLoc x) (reLoc y) [r] | '_' `notElem` srcTxt, srcTxt /= underscoredSrcTxt ]
+  [ suggest "Use underscore" (reLoc x) (reLoc y) [r] | '_' `notElem` unpackFS srcTxt, unpackFS srcTxt /= underscoredSrcTxt ]
   where
-    underscoredSrcTxt = addUnderscore srcTxt
+    underscoredSrcTxt = addUnderscore (unpackFS srcTxt)
     y :: LocatedAn an (HsExpr GhcPs)
-    y = noLocA $ HsOverLit EpAnnNotUsed $ ol{ol_val = HsIntegral intLit{il_text = SourceText underscoredSrcTxt}}
+    y = noLocA $ HsOverLit EpAnnNotUsed $ ol{ol_val = HsIntegral intLit{il_text = SourceText (fsLit underscoredSrcTxt)}}
     r = Replace Expr (toSSA x) [("a", toSSA y)] "a"
 suggestUnderscore x@(L _ (HsOverLit _ ol@(OverLit _ (HsFractional fracLit@(FL (SourceText srcTxt) _ _ _ _))))) =
-  [ suggest "Use underscore" (reLoc x) (reLoc y) [r] | '_' `notElem` srcTxt, srcTxt /= underscoredSrcTxt ]
+  [ suggest "Use underscore" (reLoc x) (reLoc y) [r] | '_' `notElem` unpackFS srcTxt, unpackFS srcTxt /= underscoredSrcTxt ]
   where
-    underscoredSrcTxt = addUnderscore srcTxt
+    underscoredSrcTxt = addUnderscore (unpackFS srcTxt)
     y :: LocatedAn an (HsExpr GhcPs)
-    y = noLocA $ HsOverLit EpAnnNotUsed $ ol{ol_val = HsFractional fracLit{fl_text = SourceText underscoredSrcTxt}}
+    y = noLocA $ HsOverLit EpAnnNotUsed $ ol{ol_val = HsFractional fracLit{fl_text = SourceText (fsLit underscoredSrcTxt)}}
     r = Replace Expr (toSSA x) [("a", toSSA y)] "a"
 suggestUnderscore _ = mempty
 

src/Hint/Restrict.hs

@@ -31,6 +31,7 @@ import Data.Set qualified as Set
 import Data.Map qualified as Map
 import Data.List.Extra
 import Data.List.NonEmpty (nonEmpty)
+import Data.Either
 import Data.Maybe
 import Data.Monoid
 import Data.Semigroup
@@ -157,6 +158,11 @@ checkPragmas modu flags exts mps =
      , not $ null bad]
    isGood def mp x = maybe def (within modu "" . riWithin) $ Map.lookup x mp
 
+
+-- | Extension to GHC's 'ImportDeclQualifiedStyle', expressing @qualifiedStyle: unrestricted@,
+-- i.e. the preference of "either pre- or post-, but qualified" in a rule.
+data QualifiedPostOrPre = QualifiedPostOrPre deriving Eq
+
 checkImports :: String -> [LImportDecl GhcPs] -> (Bool, Map.Map String RestrictItem) -> [Idea]
 checkImports modu lImportDecls (def, mp) = mapMaybe getImportHint lImportDecls
   where
@@ -190,30 +196,37 @@ checkImports modu lImportDecls (def, mp) = mapMaybe getImportHint lImportDecls
               case fromMaybe ImportStyleUnrestricted $ getAlt riImportStyle of
                 ImportStyleUnrestricted
                   | NotQualified <- ideclQualified -> (Nothing, Nothing)
-                  | otherwise -> (second (<> " or unqualified") <$> expectedQualStyle, Nothing)
-                ImportStyleQualified -> (expectedQualStyleDef, Nothing)
+                  | otherwise -> (Just $ second (<> " or unqualified") expectedQualStyle, Nothing)
+                ImportStyleQualified -> (Just expectedQualStyle, Nothing)
                 ImportStyleExplicitOrQualified
                   | Just (False, _) <- first (== EverythingBut) <$> ideclImportList -> (Nothing, Nothing)
                   | otherwise ->
-                      ( second (<> " or with an explicit import list") <$> expectedQualStyleDef
+                      ( Just $ second (<> " or with an explicit import list") expectedQualStyle
                       , Nothing )
                 ImportStyleExplicit
                   | Just (False, _) <- first (== EverythingBut) <$> ideclImportList -> (Nothing, Nothing)
                   | otherwise ->
-                      ( Just (NotQualified, "unqualified")
+                      ( Just (Right NotQualified, "unqualified")
                       , Just $ Just (Exactly, noLocA []) )
-                ImportStyleUnqualified -> (Just (NotQualified, "unqualified"), Nothing)
-            expectedQualStyleDef = expectedQualStyle <|> Just (QualifiedPre, "qualified")
+                ImportStyleUnqualified -> (Just (Right NotQualified, "unqualified"), Nothing)
             expectedQualStyle =
               case fromMaybe QualifiedStyleUnrestricted $ getAlt riQualifiedStyle of
-                QualifiedStyleUnrestricted -> Nothing
-                QualifiedStylePost -> Just (QualifiedPost, "post-qualified")
-                QualifiedStylePre -> Just (QualifiedPre, "pre-qualified")
+                QualifiedStyleUnrestricted -> (Left QualifiedPostOrPre, "qualified")
+                QualifiedStylePost -> (Right QualifiedPost, "post-qualified")
+                QualifiedStylePre -> (Right QualifiedPre, "pre-qualified")
+            -- unless expectedQual is Nothing, it holds the Idea (hint) to ultimately emit,
+            -- except in these cases when the rule's requirements are fulfilled in-source:
             qualIdea
-              | Just ideclQualified == (fst <$> expectedQual) = Nothing
+              -- the rule demands a particular importStyle, and the decl obeys exactly
+              | Just (Right ideclQualified) == (fst <$> expectedQual) = Nothing
+              -- the rule demands a QualifiedPostOrPre import, and the decl does either
+              | Just (Left QualifiedPostOrPre) == (fst <$> expectedQual)
+                && ideclQualified `elem` [QualifiedPost, QualifiedPre] = Nothing
+              -- otherwise, expectedQual gets converted into a warning below (or is Nothing)
               | otherwise = expectedQual
         whenJust qualIdea $ \(qual, hint) -> do
-          let i' = noLoc $ (unLoc i){ ideclQualified = qual
+          -- convert non-Nothing qualIdea into hlint's refactoring Idea
+          let i' = noLoc $ (unLoc i){ ideclQualified = fromRight QualifiedPre qual
                                     , ideclImportList = fromMaybe ideclImportList expectedHiding }
               msg = moduleNameString (unLoc ideclName) <> " should be imported " <> hint
           Left $ warn msg (reLoc i) i' []

src/Hint/Unsafe.hs

@@ -60,13 +60,15 @@ unsafeHint _ (ModuleEx (L _ m)) = \ld@(L loc d) ->
      -- 'x' is not marked 'NOINLINE'.
      , x `notElem` noinline]
   where
+    noInline = fsLit $ '{' : '-' : '#' : " NOINLINE"
+
     gen :: OccName -> LHsDecl GhcPs
     gen x = noLocA $
       SigD noExtField (InlineSig EpAnnNotUsed (noLocA (mkRdrUnqual x))
-                      (InlinePragma (SourceText "{-# NOINLINE") (NoInline (SourceText "{-# NOINLINE")) Nothing NeverActive FunLike))
+                      (InlinePragma (SourceText noInline) (NoInline (SourceText noInline)) Nothing NeverActive FunLike))
     noinline :: [OccName]
     noinline = [q | L _(SigD _ (InlineSig _ (L _ (Unqual q))
-                                                (InlinePragma _ (NoInline (SourceText "{-# NOINLINE")) Nothing NeverActive FunLike))
+                                                (InlinePragma _ (NoInline (SourceText noInline)) Nothing NeverActive FunLike))
         ) <- hsmodDecls m]
 
 isUnsafeDecl :: HsDecl GhcPs -> Bool

stack.yaml

@@ -1,12 +1,12 @@
-# For hlint/ghc-9.6.*, the minimum build compiler is ghc-9.2.2 (ghc-9.2.1 was a broken release). 9.2.2 exhibits the "'ffitarget_x86.h' file not found" problem on macOS.  in this case, build with invoke `C_INCLUDE_PATH="$(xcrun --show-sdk-path)"/usr/include/ffi stack build`.
-resolver:  nightly-2023-04-02 # ghc-9.4.4
+# For hlint/ghc-9.8.*, the minimum build compiler is ghc-9.4.1.
+resolver:  lts-21.6 # ghc-9.4.5
 
 packages:
   - .
 
 extra-deps:
-  - ghc-lib-parser-9.6.2.20230523
-  - ghc-lib-parser-ex-9.6.0.2
+  - ghc-lib-parser-9.8.1.20231009
+  - ghc-lib-parser-ex-9.8.0.0
 # To test hlint against experimental builds of ghc-lib-parser-ex,
 # modify extra-deps like this:
 #  - archive: /users/shayne/project/ghc-lib-parser-ex/ghc-lib-parser-ex-8.10.0.18.tar.gz

tests/import_style.test

@@ -66,3 +66,64 @@ OUTPUT
 No hints
 
 ---------------------------------------------------------------------
+RUN tests/importStyle-postqual-pos.hs --hint=data/import_style.yaml -XImportQualifiedPost
+FILE tests/importStyle-postqual-pos.hs
+import HypotheticalModule1 qualified as HM1
+import HypotheticalModule2 qualified
+import HypotheticalModule2 qualified as Arbitrary
+import HypotheticalModule3 qualified
+import HypotheticalModule3 qualified as Arbitrary
+import HypotheticalModule4 qualified as HM4
+import HypotheticalModule5 qualified
+import HypotheticalModule5 qualified as HM5
+OUTPUT
+No hints
+
+---------------------------------------------------------------------
+RUN tests/importStyle-postqual-neg.hs --hint=data/import_style.yaml -XImportQualifiedPost
+FILE tests/importStyle-postqual-neg.hs
+import HypotheticalModule1 qualified
+import qualified HypotheticalModule4
+import qualified HypotheticalModule4 as Verbotten
+import qualified HypotheticalModule4 as HM4
+import HypotheticalModule5 as HM5
+import qualified HypotheticalModule5
+
+OUTPUT
+tests/importStyle-postqual-neg.hs:1:1-36: Warning: Avoid restricted alias
+Found:
+  import HypotheticalModule1 qualified
+Perhaps:
+  import HypotheticalModule1 qualified as HM1
+Note: may break the code
+
+tests/importStyle-postqual-neg.hs:2:1-36: Warning: Avoid restricted alias
+Found:
+  import qualified HypotheticalModule4
+Perhaps:
+  import qualified HypotheticalModule4 as HM4
+Note: may break the code
+
+tests/importStyle-postqual-neg.hs:3:1-49: Warning: Avoid restricted alias
+Found:
+  import qualified HypotheticalModule4 as Verbotten
+Perhaps:
+  import qualified HypotheticalModule4 as HM4
+Note: may break the code
+
+tests/importStyle-postqual-neg.hs:5:1-33: Warning: HypotheticalModule5 should be imported post-qualified
+Found:
+  import HypotheticalModule5 as HM5
+Perhaps:
+  import HypotheticalModule5 qualified as HM5
+Note: may break the code
+
+tests/importStyle-postqual-neg.hs:6:1-36: Warning: HypotheticalModule5 should be imported post-qualified
+Found:
+  import qualified HypotheticalModule5
+Perhaps:
+  import HypotheticalModule5 qualified
+Note: may break the code
+
+5 hints
+---------------------------------------------------------------------