Convert diagnostics in GHC.Rename.Bind to proper TcRnMessage (#20115)

I removed all occurrences of TcRnUnknownMessage in GHC.Rename.Bind
module. Instead, these TcRnMessage messages were introduced:
  TcRnMultipleFixityDecls
  TcRnIllegalPatternSynonymDecl
  TcRnIllegalClassBiding
  TcRnOrphanCompletePragma
  TcRnEmptyCase
  TcRnNonStdGuards
  TcRnDuplicateSigDecl
  TcRnMisplacedSigDecl
  TcRnUnexpectedDefaultSig
  TcRnBindInBootFile
  TcRnDuplicateMinimalSig

31 files changed, 419 insertions, 113 deletions

diff --git a/compiler/GHC/Rename/Bind.hs b/compiler/GHC/Rename/Bind.hs
index fa5c7b8532..0849c9810f 100644
--- a/compiler/GHC/Rename/Bind.hs
+++ b/compiler/GHC/Rename/Bind.hs
@@ -72,8 +72,7 @@ import qualified GHC.LanguageExtensions as LangExt
 import Language.Haskell.Syntax.Basic (FieldLabelString(..))
 
 import Control.Monad
-import Data.Foldable      ( toList )
-import Data.List          ( partition, sortBy )
+import Data.List          ( partition )
 import Data.List.NonEmpty ( NonEmpty(..) )
 
 {-
@@ -690,16 +689,10 @@ makeMiniFixityEnv decls = foldlM add_one_sig emptyFsEnv decls
          Nothing -> return $ extendFsEnv env fs fix_item
          Just (L loc' _) -> do
            { setSrcSpan loc $
-             addErrAt name_loc (dupFixityDecl loc' name)
+             addErrAt name_loc (TcRnMultipleFixityDecls loc' name)
            ; return env}
      }
 
-dupFixityDecl :: SrcSpan -> RdrName -> TcRnMessage
-dupFixityDecl loc rdr_name
-  = mkTcRnUnknownMessage $ mkPlainError noHints $
-    vcat [text "Multiple fixity declarations for" <+> quotes (ppr rdr_name),
-          text "also at " <+> ppr loc]
-
 
 {- *********************************************************************
 *                                                                      *
@@ -716,7 +709,7 @@ rnPatSynBind sig_fn bind@(PSB { psb_id = L l name
                               , psb_dir = dir })
        -- invariant: no free vars here when it's a FunBind
   = do  { pattern_synonym_ok <- xoptM LangExt.PatternSynonyms
-        ; unless pattern_synonym_ok (addErr patternSynonymErr)
+        ; unless pattern_synonym_ok (addErr TcRnIllegalPatternSynonymDecl)
         ; let scoped_tvs = sig_fn name
 
         ; ((pat', details'), fvs1) <- bindSigTyVarsFV scoped_tvs $
@@ -785,11 +778,6 @@ rnPatSynBind sig_fn bind@(PSB { psb_id = L l name
     -- See Note [Renaming pattern synonym variables]
     lookupPatSynBndr = wrapLocMA lookupLocalOccRn
 
-    patternSynonymErr :: TcRnMessage
-    patternSynonymErr
-      = mkTcRnUnknownMessage $ mkPlainError noHints $
-        hang (text "Illegal pattern synonym declaration")
-           2 (text "Use -XPatternSynonyms to enable this extension")
 
 {-
 Note [Renaming pattern synonym variables]
@@ -943,18 +931,11 @@ rnMethodBindLHS _ cls (L loc bind@(FunBind { fun_id = name })) rest
 -- Report error for all other forms of bindings
 -- This is why we use a fold rather than map
 rnMethodBindLHS is_cls_decl _ (L loc bind) rest
-  = do { addErrAt (locA loc) $ mkTcRnUnknownMessage $ mkPlainError noHints $
-         vcat [ what <+> text "not allowed in" <+> decl_sort
-              , nest 2 (ppr bind) ]
+  = do { addErrAt (locA loc) $ TcRnIllegalClassBinding decl_sort bind
        ; return rest }
   where
-    decl_sort | is_cls_decl = text "class declaration:"
-              | otherwise   = text "instance declaration:"
-    what = case bind of
-              PatBind {}    -> text "Pattern bindings (except simple variables)"
-              PatSynBind {} -> text "Pattern synonyms"
-                               -- Associated pattern synonyms are not implemented yet
-              _ -> pprPanic "rnMethodBind" (ppr bind)
+    decl_sort | is_cls_decl = ClassDeclSort
+              | otherwise   = InstanceDeclSort
 
 {-
 ************************************************************************
@@ -1009,7 +990,7 @@ renameSig ctxt sig@(TypeSig _ vs ty)
 renameSig ctxt sig@(ClassOpSig _ is_deflt vs ty)
   = do  { defaultSigs_on <- xoptM LangExt.DefaultSignatures
         ; when (is_deflt && not defaultSigs_on) $
-          addErr (defaultSigErr sig)
+          addErr (TcRnUnexpectedDefaultSig sig)
         ; mapM_ warnForallIdentifier vs
         ; new_v <- mapM (lookupSigOccRnN ctxt sig) vs
         ; (new_ty, fvs) <- rnHsSigType ty_ctxt TypeLevel ty
@@ -1083,15 +1064,10 @@ renameSig _ctxt sig@(CompleteMatchSig (_, s) (L l bf) mty)
        this_mod <- fmap tcg_mod getGblEnv
        unless (any (nameIsLocalOrFrom this_mod . unLoc) new_bf) $
          -- Why 'any'? See Note [Orphan COMPLETE pragmas]
-         addErrCtxt (text "In" <+> ppr sig) $ failWithTc orphanError
+         addErrCtxt (text "In" <+> ppr sig) $ failWithTc TcRnOrphanCompletePragma
 
        return (CompleteMatchSig (noAnn, s) (L l new_bf) new_mty, emptyFVs)
-  where
-    orphanError :: TcRnMessage
-    orphanError = mkTcRnUnknownMessage $ mkPlainError noHints $
-      text "Orphan COMPLETE pragmas not supported" $$
-      text "A COMPLETE pragma must mention at least one data constructor" $$
-      text "or pattern synonym defined in the same module."
+
 
 {-
 Note [Orphan COMPLETE pragmas]
@@ -1196,7 +1172,7 @@ findDupSigs sigs
 checkDupMinimalSigs :: [LSig GhcPs] -> RnM ()
 checkDupMinimalSigs sigs
   = case filter isMinimalLSig sigs of
-      minSigs@(_:_:_) -> dupMinimalSigErr minSigs
+      sig1 : sig2 : otherSigs -> dupMinimalSigErr sig1 sig2 otherSigs
       _ -> return ()
 
 {-
@@ -1246,7 +1222,7 @@ rnMatchGroup :: (Outputable (body GhcPs), AnnoBody body) => HsMatchContext GhcRn
              -> RnM (MatchGroup GhcRn (LocatedA (body GhcRn)), FreeVars)
 rnMatchGroup ctxt rnBody (MG { mg_alts = L lm ms, mg_ext = origin })
          -- see Note [Empty MatchGroups]
-  = do { whenM ((null ms &&) <$> mustn't_be_empty) (addErr (emptyCaseErr ctxt))
+  = do { whenM ((null ms &&) <$> mustn't_be_empty) (addErr (TcRnEmptyCase ctxt))
        ; (new_ms, ms_fvs) <- mapFvRn (rnMatch ctxt rnBody) ms
        ; return (mkMatchGroup origin (L lm new_ms), ms_fvs) }
   where
@@ -1277,29 +1253,6 @@ rnMatch' ctxt rnBody (Match { m_ctxt = mf, m_pats = pats, m_grhss = grhss })
         ; return (Match { m_ext = noAnn, m_ctxt = mf', m_pats = pats'
                         , m_grhss = grhss'}, grhss_fvs ) }
 
-emptyCaseErr :: HsMatchContext GhcRn -> TcRnMessage
-emptyCaseErr ctxt = mkTcRnUnknownMessage $ mkPlainError noHints $ message ctxt
-  where
-    pp_ctxt :: HsMatchContext GhcRn -> SDoc
-    pp_ctxt c = case c of
-      CaseAlt                                  -> text "case expression"
-      LamCaseAlt LamCase                       -> text "\\case expression"
-      ArrowMatchCtxt (ArrowLamCaseAlt LamCase) -> text "\\case command"
-      ArrowMatchCtxt ArrowCaseAlt              -> text "case command"
-      ArrowMatchCtxt KappaExpr                 -> text "kappa abstraction"
-      _                                        -> text "(unexpected)"
-                                                  <+> pprMatchContextNoun c
-
-    message :: HsMatchContext GhcRn -> SDoc
-    message (LamCaseAlt LamCases) = lcases_msg <+> text "expression"
-    message (ArrowMatchCtxt (ArrowLamCaseAlt LamCases)) =
-      lcases_msg <+> text "command"
-    message ctxt =
-      hang (text "Empty list of alternatives in" <+> pp_ctxt ctxt)
-           2 (text "Use EmptyCase to allow this")
-
-    lcases_msg =
-      text "Empty list of alternatives is not allowed in \\cases"
 
 {-
 ************************************************************************
@@ -1336,9 +1289,7 @@ rnGRHS' ctxt rnBody (GRHS _ guards rhs)
                                     rnBody rhs
 
         ; unless (pattern_guards_allowed || is_standard_guard guards') $
-            let diag = mkTcRnUnknownMessage $
-                  mkPlainDiagnostic WarningWithoutFlag noHints (nonStdGuardErr guards')
-            in addDiagnostic diag
+            addDiagnostic (nonStdGuardErr guards')
 
         ; return (GRHS noAnn guards' rhs', fvs) }
   where
@@ -1390,44 +1341,21 @@ rnSrcFixityDecl sig_ctxt = rn_decl
 -}
 
 dupSigDeclErr :: NonEmpty (LocatedN RdrName, Sig GhcPs) -> RnM ()
-dupSigDeclErr pairs@((L loc name, sig) :| _)
-  = addErrAt (locA loc) $ mkTcRnUnknownMessage $ mkPlainError noHints $
-    vcat [ text "Duplicate" <+> what_it_is
-           <> text "s for" <+> quotes (ppr name)
-         , text "at" <+> vcat (map ppr $ sortBy SrcLoc.leftmost_smallest
-                                       $ map (getLocA . fst)
-                                       $ toList pairs)
-         ]
-  where
-    what_it_is = hsSigDoc sig
+dupSigDeclErr pairs@((L loc _, _) :| _)
+  = addErrAt (locA loc) $ TcRnDuplicateSigDecl pairs
 
 misplacedSigErr :: LSig GhcRn -> RnM ()
 misplacedSigErr (L loc sig)
-  = addErrAt (locA loc) $ mkTcRnUnknownMessage $ mkPlainError noHints $
-    sep [text "Misplaced" <+> hsSigDoc sig <> colon, ppr sig]
-
-defaultSigErr :: Sig GhcPs -> TcRnMessage
-defaultSigErr sig = mkTcRnUnknownMessage $ mkPlainError noHints $
-  vcat [ hang (text "Unexpected default signature:")
-         2 (ppr sig)
-       , text "Use DefaultSignatures to enable default signatures" ]
+  = addErrAt (locA loc) $ TcRnMisplacedSigDecl sig
 
 bindInHsBootFileErr :: LHsBindLR GhcRn GhcPs -> RnM ()
-bindInHsBootFileErr (L loc _)
-  = addErrAt (locA loc) $ mkTcRnUnknownMessage $ mkPlainError noHints $
-      vcat [ text "Bindings in hs-boot files are not allowed" ]
+bindInHsBootFileErr (L loc _) = addErrAt (locA loc) TcRnBindInBootFile
 
 nonStdGuardErr :: (Outputable body,
                    Anno (Stmt GhcRn body) ~ SrcSpanAnnA)
-               => [LStmtLR GhcRn GhcRn body] -> SDoc
-nonStdGuardErr guards
-  = hang (text "accepting non-standard pattern guards (use PatternGuards to suppress this message)")
-       4 (interpp'SP guards)
-
-dupMinimalSigErr :: [LSig GhcPs] -> RnM ()
-dupMinimalSigErr sigs@(L loc _ : _)
-  = addErrAt (locA loc) $ mkTcRnUnknownMessage $ mkPlainError noHints $
-    vcat [ text "Multiple minimal complete definitions"
-         , text "at" <+> vcat (map ppr $ sortBy SrcLoc.leftmost_smallest $ map getLocA sigs)
-         , text "Combine alternative minimal complete definitions with `|'" ]
-dupMinimalSigErr [] = panic "dupMinimalSigErr"
+               => [LStmtLR GhcRn GhcRn body] -> TcRnMessage
+nonStdGuardErr guards = TcRnNonStdGuards (NonStandardGuards guards)
+
+dupMinimalSigErr :: LSig GhcPs -> LSig GhcPs -> [LSig GhcPs] -> RnM ()
+dupMinimalSigErr sig1 sig2 otherSigs
+  = addErrAt (getLocA sig1) $ TcRnDuplicateMinimalSig sig1 sig2 otherSigs
diff --git a/compiler/GHC/Tc/Errors/Ppr.hs b/compiler/GHC/Tc/Errors/Ppr.hs
index 3d6dfab2a4..9880c13a9c 100644
--- a/compiler/GHC/Tc/Errors/Ppr.hs
+++ b/compiler/GHC/Tc/Errors/Ppr.hs
@@ -1241,6 +1241,71 @@ instance Diagnostic TcRnMessage where
                 <+> ppr (nameSrcLoc lcl_name)
     TcRnBindingOfExistingName name -> mkSimpleDecorated $
       text "Illegal binding of an existing name:" <+> ppr (filterCTuple name)
+    TcRnMultipleFixityDecls loc rdr_name -> mkSimpleDecorated $
+      vcat [text "Multiple fixity declarations for" <+> quotes (ppr rdr_name),
+            text "also at " <+> ppr loc]
+    TcRnIllegalPatternSynonymDecl -> mkSimpleDecorated $
+      text "Illegal pattern synonym declaration"
+    TcRnIllegalClassBinding dsort bind -> mkSimpleDecorated $
+      vcat [ what <+> text "not allowed in" <+> decl_sort
+              , nest 2 (ppr bind) ]
+      where
+        decl_sort = case dsort of
+          ClassDeclSort -> text "class declaration:"
+          InstanceDeclSort -> text "instance declaration:"
+        what = case bind of
+                  PatBind {}    -> text "Pattern bindings (except simple variables)"
+                  PatSynBind {} -> text "Pattern synonyms"
+                                   -- Associated pattern synonyms are not implemented yet
+                  _ -> pprPanic "rnMethodBind" (ppr bind)
+    TcRnOrphanCompletePragma -> mkSimpleDecorated $
+      text "Orphan COMPLETE pragmas not supported" $$
+      text "A COMPLETE pragma must mention at least one data constructor" $$
+      text "or pattern synonym defined in the same module."
+    TcRnEmptyCase ctxt -> mkSimpleDecorated message
+      where
+        pp_ctxt = case ctxt of
+          CaseAlt                                  -> text "case expression"
+          LamCaseAlt LamCase                       -> text "\\case expression"
+          ArrowMatchCtxt (ArrowLamCaseAlt LamCase) -> text "\\case command"
+          ArrowMatchCtxt ArrowCaseAlt              -> text "case command"
+          ArrowMatchCtxt KappaExpr                 -> text "kappa abstraction"
+          _                                        -> text "(unexpected)"
+                                                      <+> pprMatchContextNoun ctxt
+
+        message = case ctxt of
+          LamCaseAlt LamCases -> lcases_msg <+> text "expression"
+          ArrowMatchCtxt (ArrowLamCaseAlt LamCases) -> lcases_msg <+> text "command"
+          _ -> text "Empty list of alternatives in" <+> pp_ctxt
+
+        lcases_msg =
+          text "Empty list of alternatives is not allowed in \\cases"
+    TcRnNonStdGuards (NonStandardGuards guards) -> mkSimpleDecorated $
+      text "accepting non-standard pattern guards" $$
+      nest 4 (interpp'SP guards)
+    TcRnDuplicateSigDecl pairs@((L _ name, sig) :| _) -> mkSimpleDecorated $
+      vcat [ text "Duplicate" <+> what_it_is
+            <> text "s for" <+> quotes (ppr name)
+          , text "at" <+> vcat (map ppr $ sortBy leftmost_smallest
+                                        $ map (getLocA . fst)
+                                        $ NE.toList pairs)
+          ]
+      where
+        what_it_is = hsSigDoc sig
+    TcRnMisplacedSigDecl sig -> mkSimpleDecorated $
+      sep [text "Misplaced" <+> hsSigDoc sig <> colon, ppr sig]
+    TcRnUnexpectedDefaultSig sig -> mkSimpleDecorated $
+      hang (text "Unexpected default signature:")
+         2 (ppr sig)
+    TcRnBindInBootFile -> mkSimpleDecorated $
+      text "Bindings in hs-boot files are not allowed"
+    TcRnDuplicateMinimalSig sig1 sig2 otherSigs -> mkSimpleDecorated $
+      vcat [ text "Multiple minimal complete definitions"
+           , text "at" <+> vcat (map ppr $ sortBy leftmost_smallest $ map getLocA sigs)
+           , text "Combine alternative minimal complete definitions with `|'" ]
+      where
+        sigs = sig1 : sig2 : otherSigs
+
 
   diagnosticReason = \case
     TcRnUnknownMessage m
@@ -1647,6 +1712,28 @@ instance Diagnostic TcRnMessage where
       -> WarningWithFlag Opt_WarnTermVariableCapture
     TcRnBindingOfExistingName{}
       -> ErrorWithoutFlag
+    TcRnMultipleFixityDecls{}
+      -> ErrorWithoutFlag
+    TcRnIllegalPatternSynonymDecl{}
+      -> ErrorWithoutFlag
+    TcRnIllegalClassBinding{}
+      -> ErrorWithoutFlag
+    TcRnOrphanCompletePragma{}
+      -> ErrorWithoutFlag
+    TcRnEmptyCase{}
+      -> ErrorWithoutFlag
+    TcRnNonStdGuards{}
+      -> WarningWithoutFlag
+    TcRnDuplicateSigDecl{}
+      -> ErrorWithoutFlag
+    TcRnMisplacedSigDecl{}
+      -> ErrorWithoutFlag
+    TcRnUnexpectedDefaultSig{}
+      -> ErrorWithoutFlag
+    TcRnBindInBootFile{}
+      -> ErrorWithoutFlag
+    TcRnDuplicateMinimalSig{}
+      -> ErrorWithoutFlag
 
   diagnosticHints = \case
     TcRnUnknownMessage m
@@ -2062,6 +2149,30 @@ instance Diagnostic TcRnMessage where
       -> [SuggestRenameTypeVariable]
     TcRnBindingOfExistingName{}
       -> noHints
+    TcRnMultipleFixityDecls{}
+      -> noHints
+    TcRnIllegalPatternSynonymDecl{}
+      -> [suggestExtension LangExt.PatternSynonyms]
+    TcRnIllegalClassBinding{}
+      -> noHints
+    TcRnOrphanCompletePragma{}
+      -> noHints
+    TcRnEmptyCase ctxt -> case ctxt of
+      LamCaseAlt LamCases -> noHints -- cases syntax doesn't support empty case.
+      ArrowMatchCtxt (ArrowLamCaseAlt LamCases) -> noHints
+      _ -> [suggestExtension LangExt.EmptyCase]
+    TcRnNonStdGuards{}
+      -> [suggestExtension LangExt.PatternGuards]
+    TcRnDuplicateSigDecl{}
+      -> noHints
+    TcRnMisplacedSigDecl{}
+      -> noHints
+    TcRnUnexpectedDefaultSig{}
+      -> [suggestExtension LangExt.DefaultSignatures]
+    TcRnBindInBootFile{}
+      -> noHints
+    TcRnDuplicateMinimalSig{}
+      -> noHints
 
   diagnosticCode = constructorCode
 
diff --git a/compiler/GHC/Tc/Errors/Types.hs b/compiler/GHC/Tc/Errors/Types.hs
index c377e32eaa..c1b8461839 100644
--- a/compiler/GHC/Tc/Errors/Types.hs
+++ b/compiler/GHC/Tc/Errors/Types.hs
@@ -88,6 +88,8 @@ module GHC.Tc.Errors.Types (
   , IllegalDecls(..)
   , EmptyStatementGroupErrReason(..)
   , UnexpectedStatement(..)
+  , DeclSort(..)
+  , NonStandardGuards(..)
   ) where
 
 import GHC.Prelude
@@ -2762,6 +2764,165 @@ data TcRnMessage where
                  th/T13968
   -}
   TcRnBindingOfExistingName :: RdrName -> TcRnMessage
+  {-| TcRnMultipleFixityDecls is an error triggered by multiple
+      fixity declarations for the same operator.
+
+     Example(s):
+
+       infixr 6 $$
+       infixl 4 $$
+
+     Test cases: rename/should_fail/RnMultipleFixityFail
+  -}
+  TcRnMultipleFixityDecls :: SrcSpan -> RdrName -> TcRnMessage
+
+  {-| TcRnIllegalPatternSynonymDecl is an error thrown when a user
+      defines a pattern synonyms without enabling the PatternSynonyms extension.
+
+     Example:
+
+       pattern O :: Int
+       pattern O = 0
+
+     Test cases: rename/should_fail/RnPatternSynonymFail
+  -}
+  TcRnIllegalPatternSynonymDecl :: TcRnMessage
+
+  {-| TcRnIllegalClassBinding is an error triggered by a binding
+      in a class or instance declaration of an illegal form.
+
+     Examples:
+
+        class ZeroOne a where
+          zero :: a
+          one :: a
+        instance ZeroOne Int where
+          (zero,one) = (0,1)
+
+        class C a where
+           pattern P = ()
+
+     Test cases: module/mod48
+                 patsyn/should_fail/T9705-1
+                 patsyn/should_fail/T9705-2
+                 typecheck/should_fail/tcfail021
+
+  -}
+  TcRnIllegalClassBinding :: DeclSort -> HsBindLR GhcPs GhcPs -> TcRnMessage
+
+  {-| TcRnOrphanCompletePragma is an error triggered by a {-# COMPLETE #-}
+      pragma which does not mention any data constructors or pattern synonyms
+      defined in the current module.
+
+     Test cases: patsyn/should_fail/T13349
+  -}
+  TcRnOrphanCompletePragma :: TcRnMessage
+
+  {-| TcRnEmptyCase is an error thrown when a user uses
+      a case expression with an empty list of alternatives without
+      enabling the EmptyCase extension.
+
+     Example(s):
+
+       case () of
+
+     Test cases: rename/should_fail/RnEmptyCaseFail
+  -}
+  TcRnEmptyCase :: HsMatchContext GhcRn -> TcRnMessage
+
+  {-| TcRnNonStdGuards is a warning thrown when a user uses
+      non-standard guards (e.g. patterns in guards) without
+      enabling the PatternGuards extension.
+      More realistically: the user has explicitly disabled PatternGuards,
+      as it is enabled by default with `-XHaskell2010`.
+
+     Example(s):
+
+       f | 5 <- 2 + 3 = ...
+
+     Test cases: rename/should_compile/rn049
+  -}
+  TcRnNonStdGuards :: NonStandardGuards -> TcRnMessage
+
+  {-| TcRnDuplicateSigDecl is an error triggered by two or more
+      signatures for one entity.
+
+     Examples:
+
+       f :: Int -> Bool
+       f :: Int -> Bool
+       f _ = True
+
+       g x = x
+       {-# INLINE g #-}
+       {-# NOINLINE g #-}
+
+       pattern P = ()
+       {-# COMPLETE P #-}
+       {-# COMPLETE P #-}
+
+     Test cases: module/mod68
+                 parser/should_fail/OpaqueParseFail4
+                 patsyn/should_fail/T12165
+                 rename/should_fail/rnfail048
+                 rename/should_fail/T5589
+                 rename/should_fail/T7338
+                 rename/should_fail/T7338a
+  -}
+  TcRnDuplicateSigDecl :: NE.NonEmpty (LocatedN RdrName, Sig GhcPs) -> TcRnMessage
+
+  {-| TcRnMisplacedSigDecl is an error triggered by the pragma application
+      in the wrong context, like `MINIMAL` applied to a function or
+      `SPECIALIZE` to an instance.
+
+     Example:
+
+       f x = x
+       {-# MINIMAL f #-}
+
+     Test cases: rename/should_fail/T18138
+                 warnings/minimal/WarnMinimalFail1
+  -}
+  TcRnMisplacedSigDecl :: Sig GhcRn -> TcRnMessage
+
+  {-| TcRnUnexpectedDefaultSig is an error thrown when a user uses
+      default signatures without enabling the DefaultSignatures extension.
+
+     Example:
+
+       class C a where
+         m :: a
+         default m :: Num a => a
+         m = 0
+
+     Test cases: rename/should_fail/RnDefaultSigFail
+  -}
+  TcRnUnexpectedDefaultSig :: Sig GhcPs -> TcRnMessage
+
+  {-| TcRnBindInBootFile is an error triggered by a binding in hs-boot file.
+
+     Example:
+
+       -- in an .hs-boot file:
+       x = 3
+
+     Test cases: rename/should_fail/T19781
+  -}
+  TcRnBindInBootFile :: TcRnMessage
+
+  {-| TcRnDuplicateMinimalSig is an error triggered by two or more minimal
+      signatures for one type class.
+
+     Example:
+
+       class C where
+         f :: ()
+         {-# MINIMAL f #-}
+         {-# MINIMAL f #-}
+
+     Test cases: rename/should_fail/RnMultipleMinimalPragmaFail
+  -}
+  TcRnDuplicateMinimalSig :: LSig GhcPs -> LSig GhcPs -> [LSig GhcPs] -> TcRnMessage
 
   deriving Generic
 
@@ -3991,3 +4152,12 @@ data UnexpectedStatement where
     :: Outputable (StmtLR GhcPs GhcPs body)
     => StmtLR GhcPs GhcPs body
     -> UnexpectedStatement
+
+data DeclSort = ClassDeclSort | InstanceDeclSort
+
+data NonStandardGuards where
+  NonStandardGuards
+    :: (Outputable body,
+        Anno (Stmt GhcRn body) ~ SrcSpanAnnA)
+    => [LStmtLR GhcRn GhcRn body]
+    -> NonStandardGuards
diff --git a/compiler/GHC/Types/Error/Codes.hs b/compiler/GHC/Types/Error/Codes.hs
index c46320da0d..d7b57113ee 100644
--- a/compiler/GHC/Types/Error/Codes.hs
+++ b/compiler/GHC/Types/Error/Codes.hs
@@ -501,6 +501,17 @@ type family GhcDiagnosticCode c = n | n -> c where
   GhcDiagnosticCode "TcRnNotOpenFamily"                             = 06207
   GhcDiagnosticCode "TcRnCapturedTermName"                          = 54201
   GhcDiagnosticCode "TcRnBindingOfExistingName"                     = 58805
+  GhcDiagnosticCode "TcRnMultipleFixityDecls"                       = 50419
+  GhcDiagnosticCode "TcRnIllegalPatternSynonymDecl"                 = 41507
+  GhcDiagnosticCode "TcRnIllegalClassBinding"                       = 69248
+  GhcDiagnosticCode "TcRnOrphanCompletePragma"                      = 93961
+  GhcDiagnosticCode "TcRnEmptyCase"                                 = 48010
+  GhcDiagnosticCode "TcRnNonStdGuards"                              = 59119
+  GhcDiagnosticCode "TcRnDuplicateSigDecl"                          = 31744
+  GhcDiagnosticCode "TcRnMisplacedSigDecl"                          = 87866
+  GhcDiagnosticCode "TcRnUnexpectedDefaultSig"                      = 40700
+  GhcDiagnosticCode "TcRnBindInBootFile"                            = 11247
+  GhcDiagnosticCode "TcRnDuplicateMinimalSig"                       = 85346
 
   -- IllegalNewtypeReason
   GhcDiagnosticCode "DoesNotHaveSingleField"                        = 23517
diff --git a/testsuite/tests/module/mod48.stderr b/testsuite/tests/module/mod48.stderr
index d2e2652403..96e8f7cf62 100644
--- a/testsuite/tests/module/mod48.stderr
+++ b/testsuite/tests/module/mod48.stderr
@@ -1,4 +1,4 @@
 
-mod48.hs:5:3: error:
+mod48.hs:5:3: error: [GHC-69248]
     Pattern bindings (except simple variables) not allowed in class declaration:
       (x, y) = error "foo"
diff --git a/testsuite/tests/module/mod68.stderr b/testsuite/tests/module/mod68.stderr
index 754124f15c..4d40083a44 100644
--- a/testsuite/tests/module/mod68.stderr
+++ b/testsuite/tests/module/mod68.stderr
@@ -1,5 +1,5 @@
 
-mod68.hs:4:1:
+mod68.hs:4:1: error: [GHC-31744]
     Duplicate type signatures for ‘f’
     at mod68.hs:3:1
        mod68.hs:4:1
diff --git a/testsuite/tests/parser/should_fail/OpaqueParseFail4.stderr b/testsuite/tests/parser/should_fail/OpaqueParseFail4.stderr
index 413b4fcc0c..529eb5f2ac 100644
--- a/testsuite/tests/parser/should_fail/OpaqueParseFail4.stderr
+++ b/testsuite/tests/parser/should_fail/OpaqueParseFail4.stderr
@@ -1,4 +1,5 @@
-OpaqueParseFail4.hs:6:12: error:
+
+OpaqueParseFail4.hs:6:12: error: [GHC-31744]
     Duplicate INLINE pragmas for ‘f’
     at OpaqueParseFail4.hs:5:12
        OpaqueParseFail4.hs:6:12
diff --git a/testsuite/tests/patsyn/should_fail/T12165.stderr b/testsuite/tests/patsyn/should_fail/T12165.stderr
index 881e46905e..0787b79f1a 100644
--- a/testsuite/tests/patsyn/should_fail/T12165.stderr
+++ b/testsuite/tests/patsyn/should_fail/T12165.stderr
@@ -1,5 +1,5 @@
 
-T12165.hs:5:9: error:
+T12165.hs:5:9: error: [GHC-31744]
     Duplicate pattern synonym signatures for ‘P’
     at T12165.hs:4:9
        T12165.hs:5:9
diff --git a/testsuite/tests/patsyn/should_fail/T13349.stderr b/testsuite/tests/patsyn/should_fail/T13349.stderr
index 5bf91cbaa4..29b258870f 100644
--- a/testsuite/tests/patsyn/should_fail/T13349.stderr
+++ b/testsuite/tests/patsyn/should_fail/T13349.stderr
@@ -1,5 +1,5 @@
 
-T13349.hs:5:1: error:
+T13349.hs:5:1: error: [GHC-93961]
     • Orphan COMPLETE pragmas not supported
       A COMPLETE pragma must mention at least one data constructor
       or pattern synonym defined in the same module.
diff --git a/testsuite/tests/patsyn/should_fail/T9705-1.stderr b/testsuite/tests/patsyn/should_fail/T9705-1.stderr
index 595b70362b..bf89d60be5 100644
--- a/testsuite/tests/patsyn/should_fail/T9705-1.stderr
+++ b/testsuite/tests/patsyn/should_fail/T9705-1.stderr
@@ -1,4 +1,4 @@
 
-T9705-1.hs:3:5: error:
+T9705-1.hs:3:5: error: [GHC-69248]
     Pattern synonyms not allowed in class declaration:
       pattern P = ()
diff --git a/testsuite/tests/patsyn/should_fail/T9705-2.stderr b/testsuite/tests/patsyn/should_fail/T9705-2.stderr
index 520480b2f9..60c75a36bb 100644
--- a/testsuite/tests/patsyn/should_fail/T9705-2.stderr
+++ b/testsuite/tests/patsyn/should_fail/T9705-2.stderr
@@ -1,4 +1,4 @@
 
-T9705-2.hs:6:5: error:
+T9705-2.hs:6:5: error: [GHC-69248]
     Pattern synonyms not allowed in instance declaration:
       pattern P = ()
diff --git a/testsuite/tests/rename/should_compile/rn049.stderr b/testsuite/tests/rename/should_compile/rn049.stderr
index 77df012628..5c13eb3936 100644
--- a/testsuite/tests/rename/should_compile/rn049.stderr
+++ b/testsuite/tests/rename/should_compile/rn049.stderr
@@ -1,4 +1,5 @@
 
-rn049.hs:12:6: Warning:
-    accepting non-standard pattern guards (use PatternGuards to suppress this message)
+rn049.hs:12:6: warning: [GHC-59119]
+    accepting non-standard pattern guards
         x <- 1 * 2 + 3 * 4
+    Suggested fix: Perhaps you intended to use PatternGuards
diff --git a/testsuite/tests/rename/should_fail/RnDefaultSigFail.hs b/testsuite/tests/rename/should_fail/RnDefaultSigFail.hs
new file mode 100644
index 0000000000..29a5f6a7e5
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/RnDefaultSigFail.hs
@@ -0,0 +1,6 @@
+module RnDefaultSigFail where
+
+class C a where
+  m :: a
+  default m :: Num a => a
+  m = 0
diff --git a/testsuite/tests/rename/should_fail/RnDefaultSigFail.stderr b/testsuite/tests/rename/should_fail/RnDefaultSigFail.stderr
new file mode 100644
index 0000000000..fa58838e88
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/RnDefaultSigFail.stderr
@@ -0,0 +1,4 @@
+
+RnDefaultSigFail.hs:5:3: error: [GHC-40700]
+    Unexpected default signature: default m :: Num a => a
+    Suggested fix: Perhaps you intended to use DefaultSignatures
diff --git a/testsuite/tests/rename/should_fail/RnEmptyCaseFail.hs b/testsuite/tests/rename/should_fail/RnEmptyCaseFail.hs
new file mode 100644
index 0000000000..4ba8082d6c
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/RnEmptyCaseFail.hs
@@ -0,0 +1,14 @@
+{-# LANGUAGE NoEmptyCase #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE Arrows #-}
+module RnEmptyCaseFail where
+
+f = case () of
+
+g = \case
+
+h = \cases
+
+j = proc x -> do \case
+
+k = proc x -> do case () of
diff --git a/testsuite/tests/rename/should_fail/RnEmptyCaseFail.stderr b/testsuite/tests/rename/should_fail/RnEmptyCaseFail.stderr
new file mode 100644
index 0000000000..d611567a6e
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/RnEmptyCaseFail.stderr
@@ -0,0 +1,19 @@
+
+RnEmptyCaseFail.hs:6:5: error: [GHC-48010]
+    Empty list of alternatives in case expression
+    Suggested fix: Perhaps you intended to use EmptyCase
+
+RnEmptyCaseFail.hs:8:5: error: [GHC-48010]
+    Empty list of alternatives in \case expression
+    Suggested fix: Perhaps you intended to use EmptyCase
+
+RnEmptyCaseFail.hs:10:5: error: [GHC-48010]
+    Empty list of alternatives is not allowed in \cases expression
+
+RnEmptyCaseFail.hs:12:18: error: [GHC-48010]
+    Empty list of alternatives in \case command
+    Suggested fix: Perhaps you intended to use EmptyCase
+
+RnEmptyCaseFail.hs:14:18: error: [GHC-48010]
+    Empty list of alternatives in case command
+    Suggested fix: Perhaps you intended to use EmptyCase
diff --git a/testsuite/tests/rename/should_fail/RnMultipleFixityFail.hs b/testsuite/tests/rename/should_fail/RnMultipleFixityFail.hs
new file mode 100644
index 0000000000..039e6151a7
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/RnMultipleFixityFail.hs
@@ -0,0 +1,7 @@
+module RnMultipleFixityFail where
+
+
+($$) = ($)
+
+infixr 4 $$
+infixl 6 $$
diff --git a/testsuite/tests/rename/should_fail/RnMultipleFixityFail.stderr b/testsuite/tests/rename/should_fail/RnMultipleFixityFail.stderr
new file mode 100644
index 0000000000..73c3314a2e
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/RnMultipleFixityFail.stderr
@@ -0,0 +1,4 @@
+
+RnMultipleFixityFail.hs:6:10: error: [GHC-50419]
+    Multiple fixity declarations for ‘$$’
+    also at  RnMultipleFixityFail.hs:7:1-11
diff --git a/testsuite/tests/rename/should_fail/RnMultipleMinimalPragmaFail.hs b/testsuite/tests/rename/should_fail/RnMultipleMinimalPragmaFail.hs
new file mode 100644
index 0000000000..b28a6b4a6b
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/RnMultipleMinimalPragmaFail.hs
@@ -0,0 +1,9 @@
+module RnMultipleMinimalPragmaFail where
+
+class C a where
+  {-# MINIMAL m1 | m2 #-}
+  m1 :: a
+  m2 :: a
+  m2 = m1
+  m1 = m2
+  {-# MINIMAL m1 | m2 #-}
diff --git a/testsuite/tests/rename/should_fail/RnMultipleMinimalPragmaFail.stderr b/testsuite/tests/rename/should_fail/RnMultipleMinimalPragmaFail.stderr
new file mode 100644
index 0000000000..b613af6206
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/RnMultipleMinimalPragmaFail.stderr
@@ -0,0 +1,6 @@
+
+RnMultipleMinimalPragmaFail.hs:4:3: error: [GHC-85346]
+    Multiple minimal complete definitions
+    at RnMultipleMinimalPragmaFail.hs:4:3-25
+       RnMultipleMinimalPragmaFail.hs:9:3-25
+    Combine alternative minimal complete definitions with `|'
diff --git a/testsuite/tests/rename/should_fail/RnPatternSynonymFail.hs b/testsuite/tests/rename/should_fail/RnPatternSynonymFail.hs
new file mode 100644
index 0000000000..fd3c06e02c
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/RnPatternSynonymFail.hs
@@ -0,0 +1,6 @@
+{-# LANGUAGE TemplateHaskell #-}
+module RnPatternSynonymFail where
+
+import Language.Haskell.TH
+
+$(pure [ PatSynD (mkName "None") (PrefixPatSyn []) ImplBidir (ConP 'Nothing [] [])])
diff --git a/testsuite/tests/rename/should_fail/RnPatternSynonymFail.stderr b/testsuite/tests/rename/should_fail/RnPatternSynonymFail.stderr
new file mode 100644
index 0000000000..0bf8f16f04
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/RnPatternSynonymFail.stderr
@@ -0,0 +1,4 @@
+
+RnPatternSynonymFail.hs:6:2: error: [GHC-41507]
+    Illegal pattern synonym declaration
+    Suggested fix: Perhaps you intended to use PatternSynonyms
diff --git a/testsuite/tests/rename/should_fail/T18138.stderr b/testsuite/tests/rename/should_fail/T18138.stderr
index dea2871a51..afd11678f1 100644
--- a/testsuite/tests/rename/should_fail/T18138.stderr
+++ b/testsuite/tests/rename/should_fail/T18138.stderr
@@ -1,4 +1,4 @@
 
-T18138.hs:4:1: error:
+T18138.hs:4:1: error: [GHC-87866]
     Misplaced SPECIALISE instance pragma:
     {-# SPECIALISE instance Eq (T Int) #-}
diff --git a/testsuite/tests/rename/should_fail/T19781.stderr b/testsuite/tests/rename/should_fail/T19781.stderr
index 1e468715aa..ffe4a4d329 100644
--- a/testsuite/tests/rename/should_fail/T19781.stderr
+++ b/testsuite/tests/rename/should_fail/T19781.stderr
@@ -1,6 +1,6 @@
 
-T19781_A.hs-boot:4:1: error:
+T19781_A.hs-boot:4:1: error: [GHC-11247]
     Bindings in hs-boot files are not allowed
 
-T19781_A.hs-boot:7:1: error:
+T19781_A.hs-boot:7:1: error: [GHC-11247]
     Bindings in hs-boot files are not allowed
diff --git a/testsuite/tests/rename/should_fail/T5589.stderr b/testsuite/tests/rename/should_fail/T5589.stderr
index f3e5e8d05c..591a51dc74 100644
--- a/testsuite/tests/rename/should_fail/T5589.stderr
+++ b/testsuite/tests/rename/should_fail/T5589.stderr
@@ -1,5 +1,5 @@
 
-T5589.hs:4:1:
+T5589.hs:4:1: error: [GHC-31744]
     Duplicate type signatures for ‘aaa’
     at T5589.hs:3:6-8
        T5589.hs:4:1-3
diff --git a/testsuite/tests/rename/should_fail/T7338.stderr b/testsuite/tests/rename/should_fail/T7338.stderr
index ceb6753a22..138d1f2838 100644
--- a/testsuite/tests/rename/should_fail/T7338.stderr
+++ b/testsuite/tests/rename/should_fail/T7338.stderr
@@ -1,5 +1,5 @@
 
-T7338.hs:4:1:
+T7338.hs:4:1: error: [GHC-31744]
     Duplicate type signatures for ‘a’
     at T7338.hs:3:1
        T7338.hs:3:4
diff --git a/testsuite/tests/rename/should_fail/T7338a.stderr b/testsuite/tests/rename/should_fail/T7338a.stderr
index 8d6d00097c..01acd0582b 100644
--- a/testsuite/tests/rename/should_fail/T7338a.stderr
+++ b/testsuite/tests/rename/should_fail/T7338a.stderr
@@ -1,10 +1,10 @@
 
-T7338a.hs:7:4:
+T7338a.hs:7:4: error: [GHC-31744]
     Duplicate type signatures for ‘a’
     at T7338a.hs:3:1
        T7338a.hs:7:4
 
-T7338a.hs:10:1:
+T7338a.hs:10:1: error: [GHC-31744]
     Duplicate type signatures for ‘c’
     at T7338a.hs:7:1
        T7338a.hs:10:1
diff --git a/testsuite/tests/rename/should_fail/all.T b/testsuite/tests/rename/should_fail/all.T
index c25ba747e7..eee582db2b 100644
--- a/testsuite/tests/rename/should_fail/all.T
+++ b/testsuite/tests/rename/should_fail/all.T
@@ -184,3 +184,8 @@ test('T21605b', normal, compile_fail, [''])
 test('T21605c', normal, compile_fail, [''])
 test('T21605d', normal, compile_fail, [''])
 test('T22839', normal, compile_fail, [''])
+test('RnPatternSynonymFail', normal, compile_fail, [''])
+test('RnMultipleFixityFail', normal, compile_fail, [''])
+test('RnEmptyCaseFail', normal, compile_fail, [''])
+test('RnDefaultSigFail', normal, compile_fail, [''])
+test('RnMultipleMinimalPragmaFail', normal, compile_fail, [''])
diff --git a/testsuite/tests/rename/should_fail/rnfail048.stderr b/testsuite/tests/rename/should_fail/rnfail048.stderr
index 64955c3982..bd616596b2 100644
--- a/testsuite/tests/rename/should_fail/rnfail048.stderr
+++ b/testsuite/tests/rename/should_fail/rnfail048.stderr
@@ -1,5 +1,5 @@
 
-rnfail048.hs:11:12:
+rnfail048.hs:11:12: error: [GHC-31744]
     Duplicate INLINE pragmas for ‘foo’
     at rnfail048.hs:6:17-19
        rnfail048.hs:7:18-20
diff --git a/testsuite/tests/typecheck/should_fail/tcfail021.stderr b/testsuite/tests/typecheck/should_fail/tcfail021.stderr
index 03a1efc328..59f91cff67 100644
--- a/testsuite/tests/typecheck/should_fail/tcfail021.stderr
+++ b/testsuite/tests/typecheck/should_fail/tcfail021.stderr
@@ -1,4 +1,4 @@
 
-tcfail021.hs:8:5: error:
+tcfail021.hs:8:5: error: [GHC-69248]
     Pattern bindings (except simple variables) not allowed in instance declaration:
       ((==), (/=)) = (\ x -> \ y -> True, \ x -> \ y -> False)
diff --git a/testsuite/tests/warnings/minimal/WarnMinimalFail1.stderr b/testsuite/tests/warnings/minimal/WarnMinimalFail1.stderr
index 43145384e1..9acca4db07 100644
--- a/testsuite/tests/warnings/minimal/WarnMinimalFail1.stderr
+++ b/testsuite/tests/warnings/minimal/WarnMinimalFail1.stderr
@@ -1,3 +1,3 @@
 
-WarnMinimalFail1.hs:5:1:
+WarnMinimalFail1.hs:5:1: error: [GHC-87866]
     Misplaced MINIMAL pragma: {-# MINIMAL global #-}