Improve "ambiguous occurrence" error messages

This error was sometimes a bit confusing, especially when data families
were involved. This commit improves the general presentation of the
"ambiguous occurrence" error, and adds a bit of extra context in the
case of data families.

Fixes #23301

37 files changed, 251 insertions, 171 deletions

diff --git a/compiler/GHC/Rename/Utils.hs b/compiler/GHC/Rename/Utils.hs
index 7b631edac0..5c23ee60cb 100644
--- a/compiler/GHC/Rename/Utils.hs
+++ b/compiler/GHC/Rename/Utils.hs
@@ -60,9 +60,11 @@ import GHC.Driver.Session
 import GHC.Data.FastString
 import Control.Monad
 import GHC.Settings.Constants ( mAX_TUPLE_SIZE, mAX_CTUPLE_SIZE )
-import qualified Data.List.NonEmpty as NE
 import qualified GHC.LanguageExtensions as LangExt
+
 import qualified Data.List as List
+import qualified Data.List.NonEmpty as NE
+
 
 {-
 *********************************************************
@@ -501,7 +503,8 @@ addNameClashErrRn rdr_name gres
   -- already, and we don't want an error cascade.
   = return ()
   | otherwise
-  = addErr $ mkNameClashErr rdr_name gres
+  = do { gre_env <- getGlobalRdrEnv
+       ; addErr $ mkNameClashErr gre_env rdr_name gres }
   where
     -- If all the GREs are defined locally, can we skip reporting an ambiguity
     -- error at use sites, because it will have been reported already? See
@@ -514,8 +517,8 @@ addNameClashErrRn rdr_name gres
     num_flds     = length flds
     num_non_flds = length non_flds
 
-mkNameClashErr :: RdrName -> NE.NonEmpty GlobalRdrElt -> TcRnMessage
-mkNameClashErr rdr_name gres = TcRnAmbiguousName rdr_name gres
+mkNameClashErr :: GlobalRdrEnv -> RdrName -> NE.NonEmpty GlobalRdrElt -> TcRnMessage
+mkNameClashErr gre_env rdr_name gres = TcRnAmbiguousName gre_env rdr_name gres
 
 dupNamesErr :: NE.NonEmpty SrcSpan -> NE.NonEmpty RdrName -> RnM ()
 dupNamesErr locs names
diff --git a/compiler/GHC/Tc/Errors/Ppr.hs b/compiler/GHC/Tc/Errors/Ppr.hs
index 269063ae65..5a1485c1da 100644
--- a/compiler/GHC/Tc/Errors/Ppr.hs
+++ b/compiler/GHC/Tc/Errors/Ppr.hs
@@ -1840,17 +1840,19 @@ instance Diagnostic TcRnMessage where
     TcRnIllegalInferredTyVars _
       -> mkSimpleDecorated $
          text "Inferred type variables are not allowed"
-    TcRnAmbiguousName name gres
+    TcRnAmbiguousName gre_env name gres
       -> mkSimpleDecorated $
-         vcat [ text "Ambiguous occurrence" <+> quotes (ppr name)
+         vcat [ text "Ambiguous occurrence" <+> quotes (ppr name) <> dot
               , text "It could refer to"
-              , nest 3 (vcat (msg1 : msgs)) ]
+              , nest 3 (vcat msgs) ]
          where
            np1 NE.:| nps = gres
-           msg1 =  text "either" <+> ppr_gre np1
-           msgs = [text "    or" <+> ppr_gre np | np <- nps]
-           ppr_gre gre = sep [ pprAmbiguousGreName gre <> comma
-                             , pprNameProvenance gre]
+           msgs = punctuateFinal comma dot $
+                    text "either" <+> ppr_gre np1
+                 : [text "    or" <+> ppr_gre np | np <- nps]
+
+           ppr_gre gre = pprAmbiguousGreName gre_env gre
+
     TcRnBindingNameConflict name locs
       -> mkSimpleDecorated $
          vcat [text "Conflicting definitions for" <+> quotes (ppr name),
@@ -5439,17 +5441,44 @@ pprUnusedName name reason =
 --                            imported from ‘Prelude’ at T15487.hs:1:8-13
 --                     or ...
 -- See #15487
-pprAmbiguousGreName :: GlobalRdrElt -> SDoc
-pprAmbiguousGreName gre
-  | isRecFldGRE gre
-  = text "the field" <+> quotes (ppr occ) <+> parent_info
+pprAmbiguousGreName :: GlobalRdrEnv -> GlobalRdrElt -> SDoc
+pprAmbiguousGreName gre_env gre
+  | IAmRecField fld_info <- gre_info gre
+  = sep [ text "the field" <+> quotes (ppr occ) <+> parent_info fld_info <> comma
+        , pprNameProvenance gre ]
   | otherwise
-  = quotes (pp_qual <> dot <> ppr occ)
+  = sep [ quotes (pp_qual <> dot <> ppr occ) <> comma
+        , pprNameProvenance gre ]
+
   where
     occ = greOccName gre
-    parent_info = case gre_par gre of
-      NoParent -> empty
-      ParentIs { par_is = par_name } -> text "of record" <+> quotes (ppr par_name)
+    parent_info fld_info =
+      case first_con of
+        PatSynName  ps -> text "of pattern synonym" <+> quotes (ppr ps)
+        DataConName {} ->
+          case gre_par gre of
+            ParentIs par
+              -- For a data family, only reporting the family TyCon can be
+              -- unhelpful (see T23301). So we give a bit of additional
+              -- info in that case.
+              | Just par_gre <- lookupGRE_Name gre_env par
+              , IAmTyCon tc_flav <- gre_info par_gre
+              , OpenFamilyFlavour IAmData _ <- tc_flav
+              -> vcat [ ppr_cons
+                      , text "in a data family instance of" <+> quotes (ppr par) ]
+              | otherwise
+              -> text "of record" <+> quotes (ppr par)
+            NoParent -> ppr_cons
+      where
+        cons :: [ConLikeName]
+        cons = nonDetEltsUniqSet $ recFieldCons fld_info
+        first_con :: ConLikeName
+        first_con = head cons
+        ppr_cons :: SDoc
+        ppr_cons = hsep [ text "belonging to data constructor"
+                        , quotes (ppr $ nameOccName $ conLikeName_Name first_con)
+                        , if length cons > 1 then parens (text "among others") else empty
+                        ]
     pp_qual
         | gre_lcl gre
         = ppr (nameModule $ greName gre)
diff --git a/compiler/GHC/Tc/Errors/Types.hs b/compiler/GHC/Tc/Errors/Types.hs
index 4c2d29a0b5..cd80a3dbc9 100644
--- a/compiler/GHC/Tc/Errors/Types.hs
+++ b/compiler/GHC/Tc/Errors/Types.hs
@@ -4024,7 +4024,8 @@ data TcRnMessage where
       T18999_NoDisambiguateRecordFields, T19397E1, T19397E2, T23010_fail,
       tcfail037
   -}
-  TcRnAmbiguousName :: !RdrName -- ^ The name
+  TcRnAmbiguousName :: !GlobalRdrEnv
+                    -> !RdrName -- ^ The name
                     -> !(NE.NonEmpty GlobalRdrElt) -- ^ The possible matches
                     -> TcRnMessage
 
diff --git a/compiler/GHC/Tc/Module.hs b/compiler/GHC/Tc/Module.hs
index 637baba3b6..b9153b6473 100644
--- a/compiler/GHC/Tc/Module.hs
+++ b/compiler/GHC/Tc/Module.hs
@@ -989,7 +989,8 @@ checkHiBootIface'
           -- At least 2 matches: report an ambiguity error.
           (gre1,_):(gre2,_):gres_ids -> do
            addErrAt (nameSrcSpan missing_name) $
-             mkNameClashErr (nameRdrName missing_name) (gre1 NE.:| gre2 : map fst gres_ids)
+             mkNameClashErr gre_env (nameRdrName missing_name)
+               (gre1 NE.:| gre2 : map fst gres_ids)
            return Nothing
 
           -- Single match: resolve the issue.
diff --git a/compiler/GHC/Utils/Outputable.hs b/compiler/GHC/Utils/Outputable.hs
index f63d515b83..49c0b10251 100644
--- a/compiler/GHC/Utils/Outputable.hs
+++ b/compiler/GHC/Utils/Outputable.hs
@@ -47,8 +47,8 @@ module GHC.Utils.Outputable (
         blankLine, forAllLit, bullet,
         ($+$),
         cat, fcat,
-        hang, hangNotEmpty, punctuate, ppWhen, ppUnless,
-        ppWhenOption, ppUnlessOption,
+        hang, hangNotEmpty, punctuate, punctuateFinal,
+        ppWhen, ppUnless, ppWhenOption, ppUnlessOption,
         speakNth, speakN, speakNOf, plural, singular,
         isOrAre, doOrDoes, itsOrTheir, thisOrThese, hasOrHave,
         unicodeSyntax,
@@ -153,7 +153,7 @@ import Data.List (intersperse)
 import Data.List.NonEmpty (NonEmpty (..))
 import Data.Semigroup (Arg(..))
 import qualified Data.List.NonEmpty as NEL
-import Data.Time
+import Data.Time ( UTCTime )
 import Data.Time.Format.ISO8601
 import Data.Void
 
@@ -842,6 +842,21 @@ punctuate p (d:ds) = go d ds
                      go d [] = [d]
                      go d (e:es) = (d <> p) : go e es
 
+-- | Punctuate a list, e.g. with commas and dots.
+--
+-- > sep $ punctuateFinal comma dot [text "ab", text "cd", text "ef"]
+-- > ab, cd, ef.
+punctuateFinal :: IsLine doc
+               => doc   -- ^ The interstitial punctuation
+               -> doc   -- ^ The final punctuation
+               -> [doc] -- ^ The list that will have punctuation added between every adjacent pair of elements
+               -> [doc] -- ^ Punctuated list
+punctuateFinal _ _ []     = []
+punctuateFinal p q (d:ds) = go d ds
+  where
+    go d [] = [d <> q]
+    go d (e:es) = (d <> p) : go e es
+
 ppWhen, ppUnless :: IsOutput doc => Bool -> doc -> doc
 {-# INLINE CONLIKE ppWhen #-}
 ppWhen True  doc = doc
diff --git a/testsuite/tests/module/mod110.stderr b/testsuite/tests/module/mod110.stderr
index 38e9c79a54..97f7eedadb 100644
--- a/testsuite/tests/module/mod110.stderr
+++ b/testsuite/tests/module/mod110.stderr
@@ -1,7 +1,8 @@
 
 mod110.hs:11:10: error: [GHC-87543]
-    Ambiguous occurrence ‘Eq’
-    It could refer to either ‘Prelude.Eq’,
-                             imported from ‘Prelude’ at mod110.hs:4:1-14
-                             (and originally defined in ‘GHC.Classes’)
-                          or ‘M.Eq’, defined at mod110.hs:7:1
+    Ambiguous occurrence ‘Eq’.
+    It could refer to
+       either ‘Prelude.Eq’,
+              imported from ‘Prelude’ at mod110.hs:4:1-14
+              (and originally defined in ‘GHC.Classes’),
+           or ‘M.Eq’, defined at mod110.hs:7:1.
diff --git a/testsuite/tests/module/mod151.stderr b/testsuite/tests/module/mod151.stderr
index 8bb41459fb..ca382a3155 100644
--- a/testsuite/tests/module/mod151.stderr
+++ b/testsuite/tests/module/mod151.stderr
@@ -1,7 +1,8 @@
 
 mod151.hs:2:20: error: [GHC-87543]
-    Ambiguous occurrence ‘id’
-    It could refer to either ‘Prelude.id’,
-                             imported from ‘Prelude’ at mod151.hs:2:8
-                             (and originally defined in ‘GHC.Base’)
-                          or ‘M.id’, defined at mod151.hs:2:30
+    Ambiguous occurrence ‘id’.
+    It could refer to
+       either ‘Prelude.id’,
+              imported from ‘Prelude’ at mod151.hs:2:8
+              (and originally defined in ‘GHC.Base’),
+           or ‘M.id’, defined at mod151.hs:2:30.
diff --git a/testsuite/tests/module/mod152.stderr b/testsuite/tests/module/mod152.stderr
index d60269b757..9742ed69ba 100644
--- a/testsuite/tests/module/mod152.stderr
+++ b/testsuite/tests/module/mod152.stderr
@@ -1,7 +1,8 @@
 
 mod152.hs:2:26: error: [GHC-87543]
-    Ambiguous occurrence ‘id’
-    It could refer to either ‘Prelude.id’,
-                             imported from ‘Prelude’ at mod152.hs:2:8
-                             (and originally defined in ‘GHC.Base’)
-                          or ‘M.id’, defined at mod152.hs:2:36
+    Ambiguous occurrence ‘id’.
+    It could refer to
+       either ‘Prelude.id’,
+              imported from ‘Prelude’ at mod152.hs:2:8
+              (and originally defined in ‘GHC.Base’),
+           or ‘M.id’, defined at mod152.hs:2:36.
diff --git a/testsuite/tests/module/mod153.stderr b/testsuite/tests/module/mod153.stderr
index 989b27a77e..7d71dbcd0a 100644
--- a/testsuite/tests/module/mod153.stderr
+++ b/testsuite/tests/module/mod153.stderr
@@ -1,7 +1,8 @@
 
 mod153.hs:2:11: error: [GHC-87543]
-    Ambiguous occurrence ‘id’
-    It could refer to either ‘Prelude.id’,
-                             imported from ‘Prelude’ at mod153.hs:2:8
-                             (and originally defined in ‘GHC.Base’)
-                          or ‘M.id’, defined at mod153.hs:2:21
+    Ambiguous occurrence ‘id’.
+    It could refer to
+       either ‘Prelude.id’,
+              imported from ‘Prelude’ at mod153.hs:2:8
+              (and originally defined in ‘GHC.Base’),
+           or ‘M.id’, defined at mod153.hs:2:21.
diff --git a/testsuite/tests/module/mod164.stderr b/testsuite/tests/module/mod164.stderr
index d6c0a9eec2..26de35564e 100644
--- a/testsuite/tests/module/mod164.stderr
+++ b/testsuite/tests/module/mod164.stderr
@@ -1,9 +1,10 @@
 
-mod164.hs:9:5: [GHC-87543]
-    Ambiguous occurrence ‘D1’
-    It could refer to either ‘Mod164_A.D1’,
-                             imported from ‘Mod164_A’ at mod164.hs:4:1-15
-                             (and originally defined at Mod164_A.hs:3:10-11)
-                          or ‘Mod164_B.D1’,
-                             imported from ‘Mod164_B’ at mod164.hs:5:1-15
-                             (and originally defined at Mod164_B.hs:3:10-11)
+mod164.hs:9:5: error: [GHC-87543]
+    Ambiguous occurrence ‘D1’.
+    It could refer to
+       either ‘Mod164_A.D1’,
+              imported from ‘Mod164_A’ at mod164.hs:4:1-15
+              (and originally defined at Mod164_A.hs:3:10-11),
+           or ‘Mod164_B.D1’,
+              imported from ‘Mod164_B’ at mod164.hs:5:1-15
+              (and originally defined at Mod164_B.hs:3:10-11).
diff --git a/testsuite/tests/module/mod165.stderr b/testsuite/tests/module/mod165.stderr
index 9ef57d4bbd..be092c086e 100644
--- a/testsuite/tests/module/mod165.stderr
+++ b/testsuite/tests/module/mod165.stderr
@@ -1,7 +1,7 @@
 
-mod165.hs:9:5: [GHC-87543]
-    Ambiguous occurrence ‘A.D1’
-    It could refer to either ‘A.D1’,
-                             imported from ‘Mod164_A’ at mod165.hs:4:1-20
-                          or ‘A.D1’, imported from ‘Mod164_B’ at mod165.hs:5:1-20
+mod165.hs:9:5: error: [GHC-87543]
+    Ambiguous occurrence ‘A.D1’.
+    It could refer to
+       either ‘A.D1’, imported from ‘Mod164_A’ at mod165.hs:4:1-20,
+           or ‘A.D1’, imported from ‘Mod164_B’ at mod165.hs:5:1-20.
 exit(1)
diff --git a/testsuite/tests/overloadedrecflds/ghci/GHCiDRF.stdout b/testsuite/tests/overloadedrecflds/ghci/GHCiDRF.stdout
index 4d4e5817d9..f68331068f 100644
--- a/testsuite/tests/overloadedrecflds/ghci/GHCiDRF.stdout
+++ b/testsuite/tests/overloadedrecflds/ghci/GHCiDRF.stdout
@@ -1,10 +1,10 @@
 GHCiDRF.foo :: T -> Int
 
 <interactive>:1:1: error: [GHC-87543]
-    Ambiguous occurrence ‘GHCiDRF.bar’
+    Ambiguous occurrence ‘GHCiDRF.bar’.
     It could refer to
-       either the field ‘bar’ of record ‘T’, defined at GHCiDRF.hs:3:28
-           or the field ‘bar’ of record ‘U’, defined at GHCiDRF.hs:4:16
+       either the field ‘bar’ of record ‘T’, defined at GHCiDRF.hs:3:28,
+           or the field ‘bar’ of record ‘U’, defined at GHCiDRF.hs:4:16.
 type T :: *
 data T = MkT {foo :: Int, ...}
   	-- Defined at GHCiDRF.hs:3:16
@@ -18,14 +18,14 @@ data U = MkU {bar :: Bool}
 GHCiDRF.foo :: GHCiDRF.T -> Int
 
 <interactive>:1:1: error: [GHC-87543]
-    Ambiguous occurrence ‘GHCiDRF.bar’
+    Ambiguous occurrence ‘GHCiDRF.bar’.
     It could refer to
-       either the field ‘bar’,
+       either the field ‘bar’ belonging to data constructor ‘MkT’,
               imported qualified from ‘GHCiDRF’
-              (and originally defined at GHCiDRF.hs:3:28-30)
-           or the field ‘bar’,
+              (and originally defined at GHCiDRF.hs:3:28-30),
+           or the field ‘bar’ belonging to data constructor ‘MkU’,
               imported qualified from ‘GHCiDRF’
-              (and originally defined at GHCiDRF.hs:4:16-18)
+              (and originally defined at GHCiDRF.hs:4:16-18).
 type GHCiDRF.T :: *
 data GHCiDRF.T = GHCiDRF.MkT {GHCiDRF.foo :: Int, ...}
   	-- Defined at GHCiDRF.hs:3:16
@@ -38,11 +38,11 @@ data GHCiDRF.U = GHCiDRF.MkU {GHCiDRF.bar :: Bool}
   	-- Defined at GHCiDRF.hs:4:16
 
 <interactive>:11:1: error: [GHC-87543]
-    Ambiguous occurrence ‘GHCiDRF.bar’
+    Ambiguous occurrence ‘GHCiDRF.bar’.
     It could refer to
-       either the field ‘bar’,
+       either the field ‘bar’ belonging to data constructor ‘MkT’,
               imported qualified from ‘GHCiDRF’
-              (and originally defined at GHCiDRF.hs:3:28-30)
-           or the field ‘bar’,
+              (and originally defined at GHCiDRF.hs:3:28-30),
+           or the field ‘bar’ belonging to data constructor ‘MkU’,
               imported qualified from ‘GHCiDRF’
-              (and originally defined at GHCiDRF.hs:4:16-18)
+              (and originally defined at GHCiDRF.hs:4:16-18).
diff --git a/testsuite/tests/overloadedrecflds/ghci/duplicaterecfldsghci01.stdout b/testsuite/tests/overloadedrecflds/ghci/duplicaterecfldsghci01.stdout
index c1bb4c99f0..c13d87bb8e 100644
--- a/testsuite/tests/overloadedrecflds/ghci/duplicaterecfldsghci01.stdout
+++ b/testsuite/tests/overloadedrecflds/ghci/duplicaterecfldsghci01.stdout
@@ -9,10 +9,12 @@ data T a = MkT {foo :: Bool, ...}
 True
 
 <interactive>:1:1: error: [GHC-87543]
-    Ambiguous occurrence ‘foo’
+    Ambiguous occurrence ‘foo’.
     It could refer to
-       either the field ‘foo’ of record ‘S’, defined at <interactive>:3:16
-           or the field ‘foo’ of record ‘T’, defined at <interactive>:4:18
+       either the field ‘foo’ of record ‘S’,
+              defined at <interactive>:3:16,
+           or the field ‘foo’ of record ‘T’,
+              defined at <interactive>:4:18.
 type U :: *
 data U = MkU {foo :: Int}
   	-- Defined at <interactive>:12:16
diff --git a/testsuite/tests/overloadedrecflds/should_compile/BootFldReexport.stderr b/testsuite/tests/overloadedrecflds/should_compile/BootFldReexport.stderr
index 29d8f451ca..b284812ce2 100644
--- a/testsuite/tests/overloadedrecflds/should_compile/BootFldReexport.stderr
+++ b/testsuite/tests/overloadedrecflds/should_compile/BootFldReexport.stderr
@@ -1,11 +1,11 @@
 
 BootFldReexport.hs:8:9: error: [GHC-87543]
-    Ambiguous occurrence ‘fld’
+    Ambiguous occurrence ‘fld’.
     It could refer to
        either ‘BootFldReexport_N.fld’,
               imported from ‘BootFldReexport_N’ at BootFldReexport.hs:4:5-7
               (and originally defined in ‘BootFldReexport_O’
-                 at BootFldReexport_O.hs-boot:4:1-13)
+                 at BootFldReexport_O.hs-boot:4:1-13),
            or the field ‘fld’ of record ‘BootFldReexport_O.O’,
               imported from ‘BootFldReexport_O’ at BootFldReexport.hs:6:5-7
-              (and originally defined at BootFldReexport_O.hs:5:16-18)
+              (and originally defined at BootFldReexport_O.hs:5:16-18).
diff --git a/testsuite/tests/overloadedrecflds/should_fail/DRFUnused.stderr b/testsuite/tests/overloadedrecflds/should_fail/DRFUnused.stderr
index 81029d6cd3..026a8b0c56 100644
--- a/testsuite/tests/overloadedrecflds/should_fail/DRFUnused.stderr
+++ b/testsuite/tests/overloadedrecflds/should_fail/DRFUnused.stderr
@@ -1,7 +1,10 @@
 
 DRFUnused.hs:18:5: error: [GHC-87543]
-    Ambiguous occurrence ‘foo’
+    Ambiguous occurrence ‘foo’.
     It could refer to
-       either the field ‘foo’ of record ‘S’, defined at DRFUnused.hs:10:16
-           or the field ‘foo’ of record ‘T’, defined at DRFUnused.hs:11:16
-           or the field ‘foo’ of record ‘U’, defined at DRFUnused.hs:12:16
+       either the field ‘foo’ of record ‘S’,
+              defined at DRFUnused.hs:10:16,
+           or the field ‘foo’ of record ‘T’,
+              defined at DRFUnused.hs:11:16,
+           or the field ‘foo’ of record ‘U’,
+              defined at DRFUnused.hs:12:16.
diff --git a/testsuite/tests/overloadedrecflds/should_fail/NoFieldSelectorsFail.stderr b/testsuite/tests/overloadedrecflds/should_fail/NoFieldSelectorsFail.stderr
index 4eb98f3778..cf92d760c2 100644
--- a/testsuite/tests/overloadedrecflds/should_fail/NoFieldSelectorsFail.stderr
+++ b/testsuite/tests/overloadedrecflds/should_fail/NoFieldSelectorsFail.stderr
@@ -1,13 +1,13 @@
 
 NoFieldSelectorsFail.hs:9:14: error: [GHC-87543]
-    Ambiguous occurrence ‘foo’
+    Ambiguous occurrence ‘foo’.
     It could refer to
        either the field ‘foo’ of record ‘Foo’,
               imported from ‘NoFieldSelectorsFailA’ at NoFieldSelectorsFail.hs:4:1-28
-              (and originally defined at NoFieldSelectorsFailA.hs:5:18-20)
+              (and originally defined at NoFieldSelectorsFailA.hs:5:18-20),
            or the field ‘foo’ of record ‘Bar’,
               imported from ‘NoFieldSelectorsFailA’ at NoFieldSelectorsFail.hs:4:1-28
-              (and originally defined at NoFieldSelectorsFailA.hs:6:18-20)
+              (and originally defined at NoFieldSelectorsFailA.hs:6:18-20).
 
 NoFieldSelectorsFail.hs:12:15: error: [GHC-56428]
     Ambiguous record field ‘foo’.
diff --git a/testsuite/tests/overloadedrecflds/should_fail/T11167_ambiguous_fixity.stderr b/testsuite/tests/overloadedrecflds/should_fail/T11167_ambiguous_fixity.stderr
index 8a1691ac22..d05c8e76fe 100644
--- a/testsuite/tests/overloadedrecflds/should_fail/T11167_ambiguous_fixity.stderr
+++ b/testsuite/tests/overloadedrecflds/should_fail/T11167_ambiguous_fixity.stderr
@@ -3,14 +3,14 @@
 [3 of 3] Compiling T11167_ambiguous_fixity ( T11167_ambiguous_fixity.hs, T11167_ambiguous_fixity.o )
 
 T11167_ambiguous_fixity.hs:6:16: error: [GHC-87543]
-    Ambiguous occurrence ‘foo’
+    Ambiguous occurrence ‘foo’.
     It could refer to
        either the field ‘foo’ of record ‘A’,
               imported from ‘T11167_ambiguous_fixity_A’ at T11167_ambiguous_fixity.hs:3:1-32
-              (and originally defined at T11167_ambiguous_fixity_A.hs:3:16-18)
+              (and originally defined at T11167_ambiguous_fixity_A.hs:3:16-18),
            or the field ‘foo’ of record ‘C’,
               imported from ‘T11167_ambiguous_fixity_A’ at T11167_ambiguous_fixity.hs:3:1-32
-              (and originally defined at T11167_ambiguous_fixity_A.hs:4:16-18)
+              (and originally defined at T11167_ambiguous_fixity_A.hs:4:16-18),
            or the field ‘foo’ of record ‘B’,
               imported from ‘T11167_ambiguous_fixity_B’ at T11167_ambiguous_fixity.hs:4:1-32
-              (and originally defined at T11167_ambiguous_fixity_B.hs:2:16-18)
+              (and originally defined at T11167_ambiguous_fixity_B.hs:2:16-18).
diff --git a/testsuite/tests/overloadedrecflds/should_fail/T13132_duplicaterecflds.stderr b/testsuite/tests/overloadedrecflds/should_fail/T13132_duplicaterecflds.stderr
index 00fbe0899b..576e6d41f6 100644
--- a/testsuite/tests/overloadedrecflds/should_fail/T13132_duplicaterecflds.stderr
+++ b/testsuite/tests/overloadedrecflds/should_fail/T13132_duplicaterecflds.stderr
@@ -1,11 +1,11 @@
 
 T13132_duplicaterecflds.hs:7:16: error: [GHC-87543]
-    Ambiguous occurrence ‘runContT’
+    Ambiguous occurrence ‘runContT’.
     It could refer to
        either the field ‘runContT’ of record ‘ContT’,
-              defined at T13132_duplicaterecflds.hs:4:31
+              defined at T13132_duplicaterecflds.hs:4:31,
            or the field ‘runContT’ of record ‘ContT2’,
-              defined at T13132_duplicaterecflds.hs:5:33
+              defined at T13132_duplicaterecflds.hs:5:33.
 
 T13132_duplicaterecflds.hs:9:11: error: [GHC-46878]
     The operator ‘runContT’ [infixl 9] of a section
@@ -14,9 +14,9 @@ T13132_duplicaterecflds.hs:9:11: error: [GHC-46878]
         in the section: ‘`runContT` x `y` x’
 
 T13132_duplicaterecflds.hs:9:12: error: [GHC-87543]
-    Ambiguous occurrence ‘runContT’
+    Ambiguous occurrence ‘runContT’.
     It could refer to
        either the field ‘runContT’ of record ‘ContT’,
-              defined at T13132_duplicaterecflds.hs:4:31
+              defined at T13132_duplicaterecflds.hs:4:31,
            or the field ‘runContT’ of record ‘ContT2’,
-              defined at T13132_duplicaterecflds.hs:5:33
+              defined at T13132_duplicaterecflds.hs:5:33.
diff --git a/testsuite/tests/overloadedrecflds/should_fail/T16745.stderr b/testsuite/tests/overloadedrecflds/should_fail/T16745.stderr
index b4515b8a19..ebc974a123 100644
--- a/testsuite/tests/overloadedrecflds/should_fail/T16745.stderr
+++ b/testsuite/tests/overloadedrecflds/should_fail/T16745.stderr
@@ -4,11 +4,11 @@
 [4 of 4] Compiling T16745A          ( T16745A.hs, T16745A.o )
 
 T16745A.hs:8:9: error: [GHC-87543]
-    Ambiguous occurrence ‘field’
+    Ambiguous occurrence ‘field’.
     It could refer to
        either ‘T16745B.field’,
               imported from ‘T16745B’ at T16745A.hs:3:24-28
-              (and originally defined in ‘T16745C’ at T16745C.hs:2:1-5)
+              (and originally defined in ‘T16745C’ at T16745C.hs:2:1-5),
            or the field ‘field’ of record ‘T16745B.R’,
               imported from ‘T16745B’ at T16745A.hs:3:24-28
-              (and originally defined at T16745B.hs:11:14-18)
+              (and originally defined at T16745B.hs:11:14-18).
diff --git a/testsuite/tests/overloadedrecflds/should_fail/T17420.stderr b/testsuite/tests/overloadedrecflds/should_fail/T17420.stderr
index 3a94cd5639..3079d44aba 100644
--- a/testsuite/tests/overloadedrecflds/should_fail/T17420.stderr
+++ b/testsuite/tests/overloadedrecflds/should_fail/T17420.stderr
@@ -2,11 +2,11 @@
 [2 of 2] Compiling T17420           ( T17420.hs, T17420.o )
 
 T17420.hs:6:17: error: [GHC-87543]
-    Ambiguous occurrence ‘name’
+    Ambiguous occurrence ‘name’.
     It could refer to
        either the field ‘name’ of record ‘Dog’,
               imported from ‘T17420A’ at T17420.hs:4:1-14
-              (and originally defined at T17420A.hs:4:18-21)
+              (and originally defined at T17420A.hs:4:18-21),
            or the field ‘name’ of record ‘Human’,
               imported from ‘T17420A’ at T17420.hs:4:1-14
-              (and originally defined at T17420A.hs:5:22-25)
+              (and originally defined at T17420A.hs:5:22-25).
diff --git a/testsuite/tests/overloadedrecflds/should_fail/T18999_NoDisambiguateRecordFields.stderr b/testsuite/tests/overloadedrecflds/should_fail/T18999_NoDisambiguateRecordFields.stderr
index 7e7939e028..a54338cbf0 100644
--- a/testsuite/tests/overloadedrecflds/should_fail/T18999_NoDisambiguateRecordFields.stderr
+++ b/testsuite/tests/overloadedrecflds/should_fail/T18999_NoDisambiguateRecordFields.stderr
@@ -1,12 +1,12 @@
 
 T18999_NoDisambiguateRecordFields.hs:6:13: error: [GHC-87543]
-    Ambiguous occurrence ‘not’
+    Ambiguous occurrence ‘not’.
     It could refer to
        either ‘Prelude.not’,
               imported from ‘Prelude’ at T18999_NoDisambiguateRecordFields.hs:2:8-40
-              (and originally defined in ‘GHC.Classes’)
+              (and originally defined in ‘GHC.Classes’),
            or the field ‘not’ of record ‘Foo’,
-              defined at T18999_NoDisambiguateRecordFields.hs:4:18
+              defined at T18999_NoDisambiguateRecordFields.hs:4:18.
 
 T18999_NoDisambiguateRecordFields.hs:8:11: error: [GHC-56428]
     Ambiguous record field ‘not’.
diff --git a/testsuite/tests/overloadedrecflds/should_fail/T23010_fail.stderr b/testsuite/tests/overloadedrecflds/should_fail/T23010_fail.stderr
index 6a1b76dae9..6b31785f07 100644
--- a/testsuite/tests/overloadedrecflds/should_fail/T23010_fail.stderr
+++ b/testsuite/tests/overloadedrecflds/should_fail/T23010_fail.stderr
@@ -1,8 +1,8 @@
 
 T23010_fail.hs-boot:7:1: error: [GHC-87543]
-    Ambiguous occurrence ‘T23010_fail.fld’
+    Ambiguous occurrence ‘T23010_fail.fld’.
     It could refer to
        either the field ‘fld’ of record ‘A’,
-              defined at T23010_fail.hs:6:16
+              defined at T23010_fail.hs:6:16,
            or the field ‘fld’ of record ‘B’,
-              defined at T23010_fail.hs:7:16
+              defined at T23010_fail.hs:7:16.
diff --git a/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail02.stderr b/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail02.stderr
index aaf57bd710..932f99ad32 100644
--- a/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail02.stderr
+++ b/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail02.stderr
@@ -1,8 +1,8 @@
 
 overloadedrecfldsfail02.hs:8:18: error: [GHC-87543]
-    Ambiguous occurrence ‘x’
+    Ambiguous occurrence ‘x’.
     It could refer to
        either the field ‘x’ of record ‘R’,
-              defined at overloadedrecfldsfail02.hs:5:16
+              defined at overloadedrecfldsfail02.hs:5:16,
            or the field ‘x’ of record ‘S’,
-              defined at overloadedrecfldsfail02.hs:6:16
+              defined at overloadedrecfldsfail02.hs:6:16.
diff --git a/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail04.stderr b/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail04.stderr
index d319ae53f6..91ddc1721b 100644
--- a/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail04.stderr
+++ b/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail04.stderr
@@ -2,11 +2,11 @@
 [2 of 3] Compiling Main             ( overloadedrecfldsfail04.hs, overloadedrecfldsfail04.o )
 
 overloadedrecfldsfail04.hs:9:6: error: [GHC-87543]
-    Ambiguous occurrence ‘I.x’
+    Ambiguous occurrence ‘I.x’.
     It could refer to
        either the field ‘x’ of record ‘V’,
               imported from ‘OverloadedRecFldsFail04_A’ at overloadedrecfldsfail04.hs:6:1-37
-              (and originally defined at OverloadedRecFldsFail04_A.hs:6:16)
+              (and originally defined at OverloadedRecFldsFail04_A.hs:6:16),
            or the field ‘x’ of record ‘U’,
               imported from ‘OverloadedRecFldsFail04_A’ at overloadedrecfldsfail04.hs:6:1-37
-              (and originally defined at OverloadedRecFldsFail04_A.hs:5:16)
+              (and originally defined at OverloadedRecFldsFail04_A.hs:5:16).
diff --git a/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail11.stderr b/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail11.stderr
index 423472841c..02316fbe92 100644
--- a/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail11.stderr
+++ b/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail11.stderr
@@ -2,11 +2,11 @@
 [2 of 3] Compiling Main             ( overloadedrecfldsfail11.hs, overloadedrecfldsfail11.o )
 
 overloadedrecfldsfail11.hs:5:15: error: [GHC-87543]
-    Ambiguous occurrence ‘foo’
+    Ambiguous occurrence ‘foo’.
     It could refer to
        either the field ‘foo’ of record ‘S’,
               imported from ‘OverloadedRecFldsFail11_A’ at overloadedrecfldsfail11.hs:3:1-32
-              (and originally defined at OverloadedRecFldsFail11_A.hs:5:16-18)
+              (and originally defined at OverloadedRecFldsFail11_A.hs:5:16-18),
            or the field ‘foo’ of record ‘T’,
               imported from ‘OverloadedRecFldsFail11_A’ at overloadedrecfldsfail11.hs:3:1-32
-              (and originally defined at OverloadedRecFldsFail11_A.hs:6:16-18)
+              (and originally defined at OverloadedRecFldsFail11_A.hs:6:16-18).
diff --git a/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail12.stderr b/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail12.stderr
index a6abb29b19..92bf5a8217 100644
--- a/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail12.stderr
+++ b/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail12.stderr
@@ -2,19 +2,19 @@
 [2 of 3] Compiling Main             ( overloadedrecfldsfail12.hs, overloadedrecfldsfail12.o )
 
 overloadedrecfldsfail12.hs:13:5: error: [GHC-87543]
-    Ambiguous occurrence ‘foo’
+    Ambiguous occurrence ‘foo’.
     It could refer to
        either the field ‘foo’ of record ‘T’,
               imported from ‘OverloadedRecFldsFail12_A’ at overloadedrecfldsfail12.hs:4:1-32
-              (and originally defined at OverloadedRecFldsFail12_A.hs:5:16-18)
+              (and originally defined at OverloadedRecFldsFail12_A.hs:5:16-18),
            or the field ‘foo’ of record ‘S’,
-              defined at overloadedrecfldsfail12.hs:6:16
+              defined at overloadedrecfldsfail12.hs:6:16.
 
 overloadedrecfldsfail12.hs:16:5: error: [GHC-87543]
-    Ambiguous occurrence ‘foo’
+    Ambiguous occurrence ‘foo’.
     It could refer to
        either the field ‘foo’ of record ‘T’,
               imported from ‘OverloadedRecFldsFail12_A’ at overloadedrecfldsfail12.hs:4:1-32
-              (and originally defined at OverloadedRecFldsFail12_A.hs:5:16-18)
+              (and originally defined at OverloadedRecFldsFail12_A.hs:5:16-18),
            or the field ‘foo’ of record ‘S’,
-              defined at overloadedrecfldsfail12.hs:6:16
+              defined at overloadedrecfldsfail12.hs:6:16.
diff --git a/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail13.stderr b/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail13.stderr
index cf9a7a5678..89cc10f4f6 100644
--- a/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail13.stderr
+++ b/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldsfail13.stderr
@@ -1,32 +1,32 @@
 
 overloadedrecfldsfail13.hs:10:5: error: [GHC-87543]
-    Ambiguous occurrence ‘x’
+    Ambiguous occurrence ‘x’.
     It could refer to
        either the field ‘x’ of record ‘S’,
-              defined at overloadedrecfldsfail13.hs:6:16
+              defined at overloadedrecfldsfail13.hs:6:16,
            or the field ‘x’ of record ‘T’,
-              defined at overloadedrecfldsfail13.hs:7:16
+              defined at overloadedrecfldsfail13.hs:7:16.
 
 overloadedrecfldsfail13.hs:12:5: error: [GHC-87543]
-    Ambiguous occurrence ‘x’
+    Ambiguous occurrence ‘x’.
     It could refer to
        either the field ‘x’ of record ‘S’,
-              defined at overloadedrecfldsfail13.hs:6:16
+              defined at overloadedrecfldsfail13.hs:6:16,
            or the field ‘x’ of record ‘T’,
-              defined at overloadedrecfldsfail13.hs:7:16
+              defined at overloadedrecfldsfail13.hs:7:16.
 
 overloadedrecfldsfail13.hs:15:5: error: [GHC-87543]
-    Ambiguous occurrence ‘x’
+    Ambiguous occurrence ‘x’.
     It could refer to
        either the field ‘x’ of record ‘S’,
-              defined at overloadedrecfldsfail13.hs:6:16
+              defined at overloadedrecfldsfail13.hs:6:16,
            or the field ‘x’ of record ‘T’,
-              defined at overloadedrecfldsfail13.hs:7:16
+              defined at overloadedrecfldsfail13.hs:7:16.
 
 overloadedrecfldsfail13.hs:18:5: error: [GHC-87543]
-    Ambiguous occurrence ‘x’
+    Ambiguous occurrence ‘x’.
     It could refer to
        either the field ‘x’ of record ‘S’,
-              defined at overloadedrecfldsfail13.hs:6:16
+              defined at overloadedrecfldsfail13.hs:6:16,
            or the field ‘x’ of record ‘T’,
-              defined at overloadedrecfldsfail13.hs:7:16
+              defined at overloadedrecfldsfail13.hs:7:16.
diff --git a/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldswasrunnowfail06.stderr b/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldswasrunnowfail06.stderr
index 2b90b16f97..f658bb1223 100644
--- a/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldswasrunnowfail06.stderr
+++ b/testsuite/tests/overloadedrecflds/should_fail/overloadedrecfldswasrunnowfail06.stderr
@@ -1,40 +1,40 @@
 
 overloadedrecfldswasrunnowfail06.hs:11:11: error: [GHC-87543]
-    Ambiguous occurrence ‘x’
+    Ambiguous occurrence ‘x’.
     It could refer to
        either the field ‘x’ of record ‘S’,
-              defined at overloadedrecfldswasrunnowfail06.hs:6:16
+              defined at overloadedrecfldswasrunnowfail06.hs:6:16,
            or the field ‘x’ of record ‘T’,
-              defined at overloadedrecfldswasrunnowfail06.hs:7:16
+              defined at overloadedrecfldswasrunnowfail06.hs:7:16,
            or the field ‘x’ of record ‘U’,
-              defined at overloadedrecfldswasrunnowfail06.hs:8:18
+              defined at overloadedrecfldswasrunnowfail06.hs:8:18.
 
 overloadedrecfldswasrunnowfail06.hs:13:11: error: [GHC-87543]
-    Ambiguous occurrence ‘x’
+    Ambiguous occurrence ‘x’.
     It could refer to
        either the field ‘x’ of record ‘S’,
-              defined at overloadedrecfldswasrunnowfail06.hs:6:16
+              defined at overloadedrecfldswasrunnowfail06.hs:6:16,
            or the field ‘x’ of record ‘T’,
-              defined at overloadedrecfldswasrunnowfail06.hs:7:16
+              defined at overloadedrecfldswasrunnowfail06.hs:7:16,
            or the field ‘x’ of record ‘U’,
-              defined at overloadedrecfldswasrunnowfail06.hs:8:18
+              defined at overloadedrecfldswasrunnowfail06.hs:8:18.
 
 overloadedrecfldswasrunnowfail06.hs:15:13: error: [GHC-87543]
-    Ambiguous occurrence ‘x’
+    Ambiguous occurrence ‘x’.
     It could refer to
        either the field ‘x’ of record ‘S’,
-              defined at overloadedrecfldswasrunnowfail06.hs:6:16
+              defined at overloadedrecfldswasrunnowfail06.hs:6:16,
            or the field ‘x’ of record ‘T’,
-              defined at overloadedrecfldswasrunnowfail06.hs:7:16
+              defined at overloadedrecfldswasrunnowfail06.hs:7:16,
            or the field ‘x’ of record ‘U’,
-              defined at overloadedrecfldswasrunnowfail06.hs:8:18
+              defined at overloadedrecfldswasrunnowfail06.hs:8:18.
 
 overloadedrecfldswasrunnowfail06.hs:21:20: error: [GHC-87543]
-    Ambiguous occurrence ‘x’
+    Ambiguous occurrence ‘x’.
     It could refer to
        either the field ‘x’ of record ‘S’,
-              defined at overloadedrecfldswasrunnowfail06.hs:6:16
+              defined at overloadedrecfldswasrunnowfail06.hs:6:16,
            or the field ‘x’ of record ‘T’,
-              defined at overloadedrecfldswasrunnowfail06.hs:7:16
+              defined at overloadedrecfldswasrunnowfail06.hs:7:16,
            or the field ‘x’ of record ‘U’,
-              defined at overloadedrecfldswasrunnowfail06.hs:8:18
+              defined at overloadedrecfldswasrunnowfail06.hs:8:18.
diff --git a/testsuite/tests/rename/should_fail/T11167_ambig.stderr b/testsuite/tests/rename/should_fail/T11167_ambig.stderr
index f23a644772..e4f552b3b9 100644
--- a/testsuite/tests/rename/should_fail/T11167_ambig.stderr
+++ b/testsuite/tests/rename/should_fail/T11167_ambig.stderr
@@ -1,16 +1,16 @@
 
 T11167_ambig.hs:10:13: error: [GHC-87543]
-    Ambiguous occurrence ‘runContT’
+    Ambiguous occurrence ‘runContT’.
     It could refer to
        either the field ‘runContT’ of record ‘ContT’,
-              defined at T11167_ambig.hs:6:30
+              defined at T11167_ambig.hs:6:30,
            or the field ‘runContT’ of record ‘ContT'’,
-              defined at T11167_ambig.hs:7:32
+              defined at T11167_ambig.hs:7:32.
 
 T11167_ambig.hs:17:9: error: [GHC-87543]
-    Ambiguous occurrence ‘runContT’
+    Ambiguous occurrence ‘runContT’.
     It could refer to
        either the field ‘runContT’ of record ‘ContT’,
-              defined at T11167_ambig.hs:6:30
+              defined at T11167_ambig.hs:6:30,
            or the field ‘runContT’ of record ‘ContT'’,
-              defined at T11167_ambig.hs:7:32
+              defined at T11167_ambig.hs:7:32.
diff --git a/testsuite/tests/rename/should_fail/T15487.stderr b/testsuite/tests/rename/should_fail/T15487.stderr
index a02cbe40c2..63b2101d1f 100644
--- a/testsuite/tests/rename/should_fail/T15487.stderr
+++ b/testsuite/tests/rename/should_fail/T15487.stderr
@@ -1,8 +1,8 @@
 
 T15487.hs:7:9: error: [GHC-87543]
-    Ambiguous occurrence ‘null’
+    Ambiguous occurrence ‘null’.
     It could refer to
        either ‘Prelude.null’,
               imported from ‘Prelude’ at T15487.hs:1:8-13
-              (and originally defined in ‘Data.Foldable’)
-           or ‘T15487.null’, defined at T15487.hs:5:1
+              (and originally defined in ‘Data.Foldable’),
+           or ‘T15487.null’, defined at T15487.hs:5:1.
diff --git a/testsuite/tests/rename/should_fail/T23301.hs b/testsuite/tests/rename/should_fail/T23301.hs
new file mode 100644
index 0000000000..e487d34324
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T23301.hs
@@ -0,0 +1,9 @@
+{-# LANGUAGE DuplicateRecordFields, TypeFamilies #-}
+
+module T23301 where
+
+data family D a
+data instance D Int  = MkD1 { fld :: Int } | MkD1b | MkD1c { fld :: Int, bar :: Bool }
+data instance D Bool = MkD2 { fld :: Bool }
+
+foo = fld
diff --git a/testsuite/tests/rename/should_fail/T23301.stderr b/testsuite/tests/rename/should_fail/T23301.stderr
new file mode 100644
index 0000000000..ac6f2479d9
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T23301.stderr
@@ -0,0 +1,10 @@
+
+T23301.hs:9:7: [GHC-87543]
+    Ambiguous occurrence ‘fld’.
+    It could refer to
+       either the field ‘fld’ belonging to data constructor ‘MkD1’ (among others)
+                              in a data family instance of ‘D’,
+              defined at T23301.hs:6:31,
+           or the field ‘fld’ belonging to data constructor ‘MkD2’
+                              in a data family instance of ‘D’,
+              defined at T23301.hs:7:31.
diff --git a/testsuite/tests/rename/should_fail/all.T b/testsuite/tests/rename/should_fail/all.T
index 7ea8d6fd3a..883476aac5 100644
--- a/testsuite/tests/rename/should_fail/all.T
+++ b/testsuite/tests/rename/should_fail/all.T
@@ -188,6 +188,7 @@ test('T21605b', normal, compile_fail, [''])
 test('T21605c', normal, compile_fail, [''])
 test('T21605d', normal, compile_fail, [''])
 test('T22839', normal, compile_fail, [''])
+test('T23301', normal, compile_fail, [''])
 test('RnPatternSynonymFail', [js_broken(22261), req_th], compile_fail, [''])
 test('RnMultipleFixityFail', normal, compile_fail, [''])
 test('RnEmptyCaseFail', normal, compile_fail, [''])
diff --git a/testsuite/tests/rename/should_fail/rnfail044.stderr b/testsuite/tests/rename/should_fail/rnfail044.stderr
index 795cee0dfa..8c25ec2cda 100644
--- a/testsuite/tests/rename/should_fail/rnfail044.stderr
+++ b/testsuite/tests/rename/should_fail/rnfail044.stderr
@@ -1,8 +1,8 @@
 
 rnfail044.hs:5:12: error: [GHC-87543]
-    Ambiguous occurrence ‘splitAt’
+    Ambiguous occurrence ‘splitAt’.
     It could refer to
        either ‘Prelude.splitAt’,
               imported from ‘Prelude’ at rnfail044.hs:5:8
-              (and originally defined in ‘GHC.List’)
-           or ‘A.splitAt’, defined at rnfail044.hs:8:3
+              (and originally defined in ‘GHC.List’),
+           or ‘A.splitAt’, defined at rnfail044.hs:8:3.
diff --git a/testsuite/tests/typecheck/should_fail/T19397E1.stderr b/testsuite/tests/typecheck/should_fail/T19397E1.stderr
index 066b8f1da4..6e614caebc 100644
--- a/testsuite/tests/typecheck/should_fail/T19397E1.stderr
+++ b/testsuite/tests/typecheck/should_fail/T19397E1.stderr
@@ -1,8 +1,8 @@
 
 T19397E1.hs:1:14: error: [GHC-87543]
-    Ambiguous occurrence ‘main’
+    Ambiguous occurrence ‘main’.
     It could refer to
        either ‘T19397S.main’,
               imported from ‘T19397S’ at T19397E1.hs:2:1-14
-              (and originally defined at T19397S.hs:4:1-4)
-           or ‘Main.main’, defined at T19397E1.hs:5:1
+              (and originally defined at T19397S.hs:4:1-4),
+           or ‘Main.main’, defined at T19397E1.hs:5:1.
diff --git a/testsuite/tests/typecheck/should_fail/T19397E2.stderr b/testsuite/tests/typecheck/should_fail/T19397E2.stderr
index a66e6170ca..ec444f8f65 100644
--- a/testsuite/tests/typecheck/should_fail/T19397E2.stderr
+++ b/testsuite/tests/typecheck/should_fail/T19397E2.stderr
@@ -1,8 +1,8 @@
 
 T19397E2.hs:1:1: error: [GHC-87543]
-    Ambiguous occurrence ‘main’
+    Ambiguous occurrence ‘main’.
     It could refer to
        either ‘T19397S.main’,
               imported from ‘T19397S’ at T19397E2.hs:2:1-14
-              (and originally defined at T19397S.hs:4:1-4)
-           or ‘Main.main’, defined at T19397E2.hs:5:1
+              (and originally defined at T19397S.hs:4:1-4),
+           or ‘Main.main’, defined at T19397E2.hs:5:1.
diff --git a/testsuite/tests/typecheck/should_fail/tcfail037.stderr b/testsuite/tests/typecheck/should_fail/tcfail037.stderr
index 60432d8626..f0b809c6af 100644
--- a/testsuite/tests/typecheck/should_fail/tcfail037.stderr
+++ b/testsuite/tests/typecheck/should_fail/tcfail037.stderr
@@ -1,7 +1,8 @@
 
 tcfail037.hs:7:11: error: [GHC-87543]
-    Ambiguous occurrence ‘+’
-    It could refer to either ‘Prelude.+’,
-                             imported from ‘Prelude’ at tcfail037.hs:3:8-17
-                             (and originally defined in ‘GHC.Num’)
-                          or ‘ShouldFail.+’, defined at tcfail037.hs:10:5
+    Ambiguous occurrence ‘+’.
+    It could refer to
+       either ‘Prelude.+’,
+              imported from ‘Prelude’ at tcfail037.hs:3:8-17
+              (and originally defined in ‘GHC.Num’),
+           or ‘ShouldFail.+’, defined at tcfail037.hs:10:5.