    {-# LANGUAGE DeriveGeneric #-}
    {-# LANGUAGE FlexibleContexts #-}
    {-# LANGUAGE FlexibleInstances #-}
    {-# LANGUAGE GADTs #-}
    {-# LANGUAGE KindSignatures #-}
    {-# LANGUAGE DataKinds #-}
    {-# LANGUAGE UndecidableInstances #-}
    {-# LANGUAGE TypeApplications #-}

    module GHC.Tc.Errors.Types (
      -- * Main types
        TcRnMessage(..)
      , TcRnMessageOpts(..)
      , mkTcRnUnknownMessage
      , TcRnMessageDetailed(..)
      , TypeDataForbids(..)
      , ErrInfo(..)
      , FixedRuntimeRepProvenance(..)
      , pprFixedRuntimeRepProvenance
      , ShadowedNameProvenance(..)
      , RecordFieldPart(..)
      , IllegalNewtypeReason(..)
      , BadRecordUpdateReason(..)
      , InjectivityErrReason(..)
      , HasKinds(..)
      , hasKinds
      , SuggestUndecidableInstances(..)
      , suggestUndecidableInstances
      , SuggestUnliftedTypes(..)
      , DataSort(..), ppDataSort
      , AllowedDataResKind(..)
      , NotClosedReason(..)
      , SuggestPartialTypeSignatures(..)
      , suggestPartialTypeSignatures
      , DeriveInstanceErrReason(..)
      , UsingGeneralizedNewtypeDeriving(..)
      , usingGeneralizedNewtypeDeriving
      , DeriveAnyClassEnabled(..)
      , deriveAnyClassEnabled
      , DeriveInstanceBadConstructor(..)
      , HasWildcard(..)
      , hasWildcard
      , BadAnonWildcardContext(..)
      , SoleExtraConstraintWildcardAllowed(..)
      , DeriveGenericsErrReason(..)
      , HasAssociatedDataFamInsts(..)
      , hasAssociatedDataFamInsts
      , AssociatedTyLastVarInKind(..)
      , associatedTyLastVarInKind
      , AssociatedTyNotParamOverLastTyVar(..)
      , associatedTyNotParamOverLastTyVar
      , MissingSignature(..)
      , Exported(..)
      , HsDocContext(..)
      , FixedRuntimeRepErrorInfo(..)

      , ErrorItem(..), errorItemOrigin, errorItemEqRel, errorItemPred, errorItemCtLoc

      , SolverReport(..), SolverReportSupplementary(..)
      , SolverReportWithCtxt(..)
      , SolverReportErrCtxt(..)
      , getUserGivens, discardProvCtxtGivens
      , TcSolverReportMsg(..)
      , CannotUnifyVariableReason(..)
      , MismatchMsg(..)
      , MismatchEA(..)
      , mkPlainMismatchMsg, mkBasicMismatchMsg
      , WhenMatching(..)
      , ExpectedActualInfo(..)
      , TyVarInfo(..), SameOccInfo(..)
      , AmbiguityInfo(..)
      , CND_Extra(..)
      , FitsMbSuppressed(..)
      , ValidHoleFits(..), noValidHoleFits
      , HoleFitDispConfig(..)
      , RelevantBindings(..), pprRelevantBindings
      , PromotionErr(..), pprPECategory, peCategory
      , TermLevelUseErr(..), teCategory
      , NotInScopeError(..), mkTcRnNotInScope
      , ImportError(..)
      , HoleError(..)
      , CoercibleMsg(..)
      , PotentialInstances(..)
      , UnsupportedCallConvention(..)
      , ExpectedBackends
      , ArgOrResult(..)
      , MatchArgsContext(..), MatchArgBadMatches(..)
      , PragmaWarningInfo(..)
      , EmptyStatementGroupErrReason(..)
      , UnexpectedStatement(..)
      , DeclSort(..)
      , NonStandardGuards(..)
      , RuleLhsErrReason(..)
      , HsigShapeMismatchReason(..)
      , WrongThingSort(..)
      , StageCheckReason(..)
      , UninferrableTyVarCtx(..)
      , PatSynInvalidRhsReason(..)
      , BadFieldAnnotationReason(..)
      , SuperclassCycle(..)
      , SuperclassCycleDetail(..)
      , RoleValidationFailedReason(..)
      , DisabledClassExtension(..)
      , TyFamsDisabledReason(..)
      , TypeApplication(..)
      , BadEmptyCaseReason(..)
      , HsTypeOrSigType(..)
      , HsTyVarBndrExistentialFlag(..)
      , TySynCycleTyCons
      , BadImportKind(..)
      , DodgyImportsReason (..)
      , ImportLookupReason (..)
      , UnusedImportReason (..)
      , UnusedImportName (..)
      , NestedForallsContextsIn(..)
      , UnusedNameProv(..)
      , NonCanonicalDefinition(..)
      , NonCanonical_Monoid(..)
      , NonCanonical_Monad(..)

        -- * Errors for hs-boot and signature files
      , BadBootDecls(..)
      , MissingBootThing(..), missingBootThing
      , BootMismatch(..)
      , BootMismatchWhat(..)
      , BootTyConMismatch(..)
      , BootAxiomBranchMismatch(..)
      , BootClassMismatch(..)
      , BootMethodMismatch(..)
      , BootATMismatch(..)
      , BootDataMismatch(..)
      , BootDataConMismatch(..)
      , SynAbstractDataError(..)
      , BootListMismatch(..), BootListMismatches

        -- * Class and family instance errors
      , IllegalInstanceReason(..)
      , IllegalClassInstanceReason(..)
      , IllegalInstanceHeadReason(..)
      , IllegalHasFieldInstance(..)
      , CoverageProblem(..), FailedCoverageCondition(..)
      , IllegalFamilyInstanceReason(..)
      , InvalidFamInstQTv(..), InvalidFamInstQTvReason(..)
      , InvalidAssoc(..), InvalidAssocInstance(..)
      , InvalidAssocDefault(..), AssocDefaultBadArgs(..)

        -- * Template Haskell errors
      , THError(..), THSyntaxError(..), THNameError(..)
      , THReifyError(..), TypedTHError(..)
      , SpliceFailReason(..), RunSpliceFailReason(..)
      , AddTopDeclsError(..)
      , ConversionFailReason(..)
      , UnrepresentableTypeDescr(..)
      , LookupTHInstNameErrReason(..)
      , SplicePhase(..)
      , THDeclDescriptor(..)
      , ThingBeingConverted(..)
      , IllegalDecls(..)

      -- * Zonker errors
      , ZonkerMessage(..)

      -- FFI Errors
      , IllegalForeignTypeReason(..)
      , TypeCannotBeMarshaledReason(..)
      ) where

    import GHC.Prelude

    import GHC.Hs
    import GHC.Tc.Errors.Types.PromotionErr
    import GHC.Tc.Errors.Hole.FitTypes (HoleFit)
    import GHC.Tc.Types.Constraint
    import GHC.Tc.Types.Evidence (EvBindsVar)
    import GHC.Tc.Types.Origin ( CtOrigin (ProvCtxtOrigin), SkolemInfoAnon (SigSkol)
                               , UserTypeCtxt (PatSynCtxt), TyVarBndrs, TypedThing
                               , FixedRuntimeRepOrigin(..), InstanceWhat )
    import GHC.Tc.Types.Rank (Rank)
    import GHC.Tc.Utils.TcType (TcType, TcSigmaType, TcPredType,
                                PatersonCondFailure, PatersonCondFailureContext)
    import GHC.Types.Basic
    import GHC.Types.Error
    import GHC.Types.Avail
    import GHC.Types.Hint (UntickedPromotedThing(..))
    import GHC.Types.ForeignCall (CLabelString)
    import GHC.Types.Id.Info ( RecSelParent(..) )
    import GHC.Types.Name (NamedThing(..), Name, OccName, getSrcLoc, getSrcSpan)
    import qualified GHC.Types.Name.Occurrence as OccName
    import GHC.Types.Name.Reader
    import GHC.Types.SourceFile (HsBootOrSig(..))
    import GHC.Types.SrcLoc
    import GHC.Types.TyThing (TyThing)
    import GHC.Types.Var (Id, TyCoVar, TyVar, TcTyVar, CoVar, Specificity)
    import GHC.Types.Var.Env (TidyEnv)
    import GHC.Types.Var.Set (TyVarSet, VarSet)
    import GHC.Unit.Types (Module)
    import GHC.Utils.Outputable
    import GHC.Core.Class (Class, ClassMinimalDef, ClassOpItem, ClassATItem)
    import GHC.Core.Coercion (Coercion)
    import GHC.Core.Coercion.Axiom (CoAxBranch)
    import GHC.Core.ConLike (ConLike)
    import GHC.Core.DataCon (DataCon, FieldLabel)
    import GHC.Core.FamInstEnv (FamInst)
    import GHC.Core.InstEnv (LookupInstanceErrReason, ClsInst, DFunId)
    import GHC.Core.PatSyn (PatSyn)
    import GHC.Core.Predicate (EqRel, predTypeEqRel)
    import GHC.Core.TyCon (TyCon, Role, FamTyConFlav, AlgTyConRhs)
    import GHC.Core.Type (Kind, Type, ThetaType, PredType, ErrorMsgType, ForAllTyFlag, ForAllTyBinder)

    import GHC.Driver.Backend (Backend)
    import GHC.Unit.State (UnitState)
    import GHC.Utils.Misc (filterOut)
    import qualified GHC.LanguageExtensions as LangExt
    import GHC.Data.FastString (FastString)
    import GHC.Data.Pair
    import GHC.Exception.Type (SomeException)

    import Language.Haskell.Syntax.Basic (FieldLabelString(..))

    import qualified Data.List.NonEmpty as NE
    import           Data.Typeable (Typeable)
    import GHC.Unit.Module.Warnings (WarningCategory, WarningTxt)
    import qualified Language.Haskell.TH.Syntax as TH

    import GHC.Generics ( Generic )
    import GHC.Types.Name.Env (NameEnv)
    import GHC.Iface.Errors.Types
    import GHC.Unit.Module.ModIface (ModIface)
    import GHC.Tc.Types.TH
    import GHC.Tc.Types.BasicTypes

    data TcRnMessageOpts = TcRnMessageOpts { TcRnMessageOpts -> Bool
    tcOptsShowContext :: !Bool -- ^ Whether we show the error context or not
                                           , TcRnMessageOpts -> IfaceMessageOpts
    tcOptsIfaceOpts   :: !IfaceMessageOpts
                                           }

    {- Note [Migrating TcM Messages]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    As part of #18516, we are slowly migrating the diagnostic messages emitted
    and reported in the TcM from SDoc to TcRnMessage. Historically, GHC emitted
    some diagnostics in 3 pieces, i.e. there were lots of error-reporting functions
    that accepted 3 SDocs an input: one for the important part of the message,
    one for the context and one for any supplementary information. Consider the following:

        • Couldn't match expected type ‘Int’ with actual type ‘Char’
        • In the expression: x4
          In a stmt of a 'do' block: return (x2, x4)
          In the expression:

    Under the hood, the reporting functions in Tc.Utils.Monad were emitting "Couldn't match"
    as the important part, "In the expression" as the context and "In a stmt..In the expression"
    as the supplementary, with the context and supplementary usually smashed together so that
    the final message would be composed only by two SDoc (which would then be bulleted like in
    the example).

    In order for us to smooth out the migration to the new diagnostic infrastructure, we
    introduce the 'ErrInfo' and 'TcRnMessageDetailed' types, which serve exactly the purpose
    of bridging the two worlds together without breaking the external API or the existing
    format of messages reported by GHC.

    Using 'ErrInfo' and 'TcRnMessageDetailed' also allows us to move away from the SDoc-ridden
    diagnostic API inside Tc.Utils.Monad, enabling further refactorings.

    In the future, once the conversion will be complete and we will successfully eradicate
    any use of SDoc in the diagnostic reporting of GHC, we can surely revisit the usage and
    existence of these two types, which for now remain a "necessary evil".
    -}

    -- The majority of TcRn messages come with extra context about the error,
    -- and this newtype captures it. See Note [Migrating TcM Messages].
    data ErrInfo = ErrInfo {
        ErrInfo -> SDoc
    errInfoContext :: !SDoc
        -- ^ Extra context associated to the error.
      , ErrInfo -> SDoc
    errInfoSupplementary :: !SDoc
        -- ^ Extra supplementary info associated to the error.
      }

    -- | 'TcRnMessageDetailed' is an \"internal\" type (used only inside
    -- 'GHC.Tc.Utils.Monad' that wraps a 'TcRnMessage' while also providing
    -- any extra info needed to correctly pretty-print this diagnostic later on.
    data TcRnMessageDetailed
      = TcRnMessageDetailed !ErrInfo
                            -- ^ Extra info associated with the message
                            !TcRnMessage
      deriving (forall x. TcRnMessageDetailed -> Rep TcRnMessageDetailed x)
    -> (forall x. Rep TcRnMessageDetailed x -> TcRnMessageDetailed)
    -> Generic TcRnMessageDetailed
    forall x. Rep TcRnMessageDetailed x -> TcRnMessageDetailed
    forall x. TcRnMessageDetailed -> Rep TcRnMessageDetailed x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. TcRnMessageDetailed -> Rep TcRnMessageDetailed x
    from :: forall x. TcRnMessageDetailed -> Rep TcRnMessageDetailed x
    $cto :: forall x. Rep TcRnMessageDetailed x -> TcRnMessageDetailed
    to :: forall x. Rep TcRnMessageDetailed x -> TcRnMessageDetailed
    Generic

    mkTcRnUnknownMessage :: (Diagnostic a, Typeable a, DiagnosticOpts a ~ NoDiagnosticOpts)
                         => a -> TcRnMessage
    mkTcRnUnknownMessage :: forall a.
    (Diagnostic a, Typeable a, DiagnosticOpts a ~ NoDiagnosticOpts) =>
    a -> TcRnMessage
    mkTcRnUnknownMessage a
    diag = UnknownDiagnostic (DiagnosticOpts TcRnMessage) -> TcRnMessage
    TcRnUnknownMessage (a -> UnknownDiagnostic (DiagnosticOpts TcRnMessage)
    forall a b.
    (Diagnostic a, Typeable a, DiagnosticOpts a ~ NoDiagnosticOpts) =>
    a -> UnknownDiagnostic b
    mkSimpleUnknownDiagnostic a
    diag)
      -- Please don't use this function inside the GHC codebase;
      -- it mainly exists for users of the GHC API, such as plugins.
      --
      -- If you need to emit a new error message in the typechecker,
      -- you should add a new constructor to 'TcRnMessage' instead.

    -- | An error which might arise during typechecking/renaming.
    data TcRnMessage where
      {-| Simply wraps an unknown 'Diagnostic' message @a@. It can be used by plugins
          to provide custom diagnostic messages originated during typechecking/renaming.
      -}
      TcRnUnknownMessage :: (UnknownDiagnostic (DiagnosticOpts TcRnMessage)) -> TcRnMessage

      {-| Wrap an 'IfaceMessage' to a 'TcRnMessage' for when we attempt to load interface
          files during typechecking but encounter an error. -}

      TcRnInterfaceError :: !IfaceMessage -> TcRnMessage

      {-| TcRnMessageWithInfo is a constructor which is used when extra information is needed
          to be provided in order to qualify a diagnostic and where it was originated (and why).
          It carries an extra 'UnitState' which can be used to pretty-print some names
          and it wraps a 'TcRnMessageDetailed', which includes any extra context associated
          with this diagnostic.
      -}
      TcRnMessageWithInfo :: !UnitState
                          -- ^ The 'UnitState' will allow us to pretty-print
                          -- some diagnostics with more detail.
                          -> !TcRnMessageDetailed
                          -> TcRnMessage

      {-| TcRnWithHsDocContext annotates an error message with the context in which
          it originated.
      -}
      TcRnWithHsDocContext :: !HsDocContext
                           -> !TcRnMessage
                           -> TcRnMessage

      {-| TcRnSolverReport is the constructor used to report unsolved constraints
          after constraint solving, as well as other errors such as hole fit errors.

          See the documentation of t'TcSolverReportMsg' datatype for an overview
          of the different errors.
      -}
      TcRnSolverReport :: SolverReportWithCtxt
                       -> DiagnosticReason
                       -> TcRnMessage

      {-| TcRnSolverDepthError is an error that occurs when the constraint solver
          exceeds the maximum recursion depth.

          Example:

            class C a where { meth :: a }
            instance Cls [a] => Cls a where { meth = head . meth }

            t :: ()
            t = meth

          Test cases:
            T7788
            T8550
            T9554
            T15316A
            T17267{∅,a,b,c,e}
            T17458
            ContextStack1
            T22924b
            TcCoercibleFail
      -}
      TcRnSolverDepthError :: !Type -> !SubGoalDepth -> TcRnMessage

      {-| TcRnRedundantConstraints is a warning that is emitted when a binding
          has a user-written type signature which contains superfluous constraints.

          Example:

            f :: (Eq a, Ord a) => a -> a -> a
            f x y = (x < y) || x == y
              -- `Eq a` is superfluous: the `Ord a` constraint suffices.

          Test cases: T9939, T10632, T18036a, T20602, PluralS, T19296.
      -}
      TcRnRedundantConstraints :: [Id]
                               -> (SkolemInfoAnon, Bool)
                                  -- ^ The contextual skolem info.
                                  -- The boolean controls whether we
                                  -- want to show it in the user message.
                                  -- (Nice to keep track of the info in either case,
                                  -- for other users of the GHC API.)
                               -> TcRnMessage

      {-| TcRnInaccessibleCode is a warning that is emitted when the RHS of a pattern
          match is inaccessible, because the constraint solver has detected a contradiction.

          Example:

            data B a where { MkTrue :: B True; MkFalse :: B False }

            foo :: B False -> Bool
            foo MkFalse = False
            foo MkTrue  = True -- Inaccessible: requires True ~ False

        Test cases: T7293, T7294, T15558, T17646, T18572, T18610, tcfail167.
      -}
      TcRnInaccessibleCode :: Implication          -- ^ The implication containing a contradiction.
                           -> SolverReportWithCtxt -- ^ The contradiction.
                           -> TcRnMessage
      {-| TcRnInaccessibleCoAxBranch is a warning that is emitted when a closed type family has a
          branch which is inaccessible due to a more general, prior branch.

          Example:
            type family F a where
              F a = Int
              F Bool = Bool
          Test cases: T9085, T14066a, T9085, T6018, tc265,

      -}
      TcRnInaccessibleCoAxBranch :: TyCon      -- ^ The type family's constructor
                                 -> CoAxBranch -- ^ The inaccessible branch
                                 -> TcRnMessage
      {-| A type which was expected to have a fixed runtime representation
          does not have a fixed runtime representation.

          Example:

            data D (a :: TYPE r) = MkD a

          Test cases: T11724, T18534,
                      RepPolyPatSynArg, RepPolyPatSynUnliftedNewtype,
                      RepPolyPatSynRes, T20423
      -}
      TcRnTypeDoesNotHaveFixedRuntimeRep :: !Type
                                         -> !FixedRuntimeRepProvenance
                                         -> !ErrInfo -- Extra info accumulated in the TcM monad
                                         -> TcRnMessage

      {-| TcRnImplicitLift is a warning (controlled with -Wimplicit-lift) that occurs when
          a Template Haskell quote implicitly uses 'lift'.

         Example:
           warning1 :: Lift t => t -> Q Exp
           warning1 x = [| x |]

         Test cases: th/T17804
      -}
      TcRnImplicitLift :: Name -> !ErrInfo -> TcRnMessage

      {-| TcRnUnusedPatternBinds is a warning (controlled with -Wunused-pattern-binds)
          that occurs if a pattern binding binds no variables at all, unless it is a
          lone wild-card pattern, or a banged pattern.

         Example:
            Just _ = rhs3    -- Warning: unused pattern binding
            (_, _) = rhs4    -- Warning: unused pattern binding
            _  = rhs3        -- No warning: lone wild-card pattern
            !() = rhs4       -- No warning: banged pattern; behaves like seq

         Test cases: rename/{T13646,T17c,T17e,T7085}
      -}
      TcRnUnusedPatternBinds :: HsBind GhcRn -> TcRnMessage

      {-| TcRnUnusedQuantifiedTypeVar is a warning that occurs if there are unused
          quantified type variables.

          Examples:
            f :: forall a. Int -> Char

          Test cases: rename/should_compile/ExplicitForAllRules1
                      rename/should_compile/T5331
      -}
      TcRnUnusedQuantifiedTypeVar
        :: HsDocContext
        -> HsTyVarBndrExistentialFlag -- ^ tyVar binder.
        -> TcRnMessage

      {-| TcRnDodgyImports is a group of warnings (controlled with -Wdodgy-imports).

          See 'DodgyImportsReason' for the different warnings.
      -}
      TcRnDodgyImports :: !DodgyImportsReason -> TcRnMessage
      {-| TcRnDodgyExports is a warning (controlled by -Wdodgy-exports) that occurs when
          an export of the form 'T(..)' for a type constructor 'T' does not actually export anything
          beside 'T' itself.

         Example:
           module Foo (
               T(..)  -- Warning: T is a type synonym
             , A(..)  -- Warning: A is a type family
             , C(..)  -- Warning: C is a data family
             ) where

           type T = Int
           type family A :: * -> *
           data family C :: * -> *

         Test cases: warnings/should_compile/DodgyExports01
      -}
      TcRnDodgyExports :: GlobalRdrElt -> TcRnMessage
      {-| TcRnMissingImportList is a warning (controlled by -Wmissing-import-lists) that occurs when
          an import declaration does not explicitly list all the names brought into scope.

         Test cases: rename/should_compile/T4489
      -}
      TcRnMissingImportList :: IE GhcPs -> TcRnMessage
      {-| When a module marked trustworthy or unsafe (using -XTrustworthy or -XUnsafe) is compiled
          with a plugin, the TcRnUnsafeDueToPlugin warning (controlled by -Wunsafe) is used as the
          reason the module was inferred to be unsafe. This warning is not raised if the
          -fplugin-trustworthy flag is passed.

         Test cases: plugins/T19926
      -}
      TcRnUnsafeDueToPlugin :: TcRnMessage
      {-| TcRnModMissingRealSrcSpan is an error that occurs when compiling a module that lacks
          an associated 'RealSrcSpan'.

         Test cases: None
      -}
      TcRnModMissingRealSrcSpan :: Module -> TcRnMessage
      {-| TcRnIdNotExportedFromModuleSig is an error pertaining to backpack that occurs
          when an identifier required by a signature is not exported by the module
          or signature that is being used as a substitution for that signature.

          Example(s): None

         Test cases: backpack/should_fail/bkpfail36
      -}
      TcRnIdNotExportedFromModuleSig :: Name -> Module -> TcRnMessage
      {-| TcRnIdNotExportedFromLocalSig is an error pertaining to backpack that
          occurs when an identifier which is necessary for implementing a module
          signature is not exported from that signature.

          Example(s): None

         Test cases: backpack/should_fail/bkpfail30
                     backpack/should_fail/bkpfail31
                     backpack/should_fail/bkpfail34
      -}
      TcRnIdNotExportedFromLocalSig :: Name -> TcRnMessage

      {-| TcRnShadowedName is a warning (controlled by -Wname-shadowing) that occurs whenever
          an inner-scope value has the same name as an outer-scope value, i.e. the inner
          value shadows the outer one. This can catch typographical errors that turn into
          hard-to-find bugs. The warning is suppressed for names beginning with an underscore.

          Examples(s):
            f = ... let f = id in ... f ...  -- NOT OK, 'f' is shadowed
            f x = do { _ignore <- this; _ignore <- that; return (the other) } -- suppressed via underscore

         Test cases: typecheck/should_compile/T10971a
                     rename/should_compile/rn039
                     rename/should_compile/rn064
                     rename/should_compile/T1972
                     rename/should_fail/T2723
                     rename/should_compile/T3262
                     driver/werror
                     rename/should_fail/T22478d
                     typecheck/should_fail/TyAppPat_ScopedTyVarConflict
      -}
      TcRnShadowedName :: OccName -> ShadowedNameProvenance -> TcRnMessage

      {-| TcRnInvalidWarningCategory is an error that occurs when a warning is declared
          with a category name that is not the special category "deprecations", and
          either does not begin with the prefix "x-" indicating a user-defined
          category, or contains characters not valid in category names.  See Note
          [Warning categories] in GHC.Unit.Module.Warnings

          Examples(s):
            module M {-# WARNING in "invalid" "Oops" #-} where

            {-# WARNING in "x- spaces not allowed" foo "Oops" #-}

         Test cases: warnings/should_fail/WarningCategoryInvalid
      -}
      TcRnInvalidWarningCategory :: !WarningCategory -> TcRnMessage

      {-| TcRnDuplicateWarningDecls is an error that occurs whenever
          a warning is declared twice.

          Examples(s):
            {-# DEPRECATED foo "Don't use me" #-}
            {-# DEPRECATED foo "Don't use me" #-}
            foo :: Int
            foo = 2

         Test cases:
            rename/should_fail/rnfail058
      -}
      TcRnDuplicateWarningDecls :: !(LocatedN RdrName) -> !RdrName -> TcRnMessage

      {-| TcRnSimplifierTooManyIterations is an error that occurs whenever
          the constraint solver in the simplifier hits the iterations' limit.

          Examples(s):
            None.

         Test cases:
            None.
      -}
      TcRnSimplifierTooManyIterations :: Cts
                                      -> !IntWithInf
                                      -- ^ The limit.
                                      -> WantedConstraints
                                      -> TcRnMessage

      {-| TcRnIllegalPatSynDecl is an error that occurs whenever
          there is an illegal pattern synonym declaration.

          Examples(s):

          varWithLocalPatSyn x = case x of
              P -> ()
            where
              pattern P = ()   -- not valid, it can't be local, it must be defined at top-level.

         Test cases: patsyn/should_fail/local
      -}
      TcRnIllegalPatSynDecl :: !(LIdP GhcPs) -> TcRnMessage

      {-| TcRnLinearPatSyn is an error that occurs whenever a pattern
          synonym signature uses a field that is not unrestricted.

          Example(s): None

         Test cases: linear/should_fail/LinearPatSyn2
      -}
      TcRnLinearPatSyn :: !Type -> TcRnMessage

      {-| TcRnEmptyRecordUpdate is an error that occurs whenever
          a record is updated without specifying any field.

          Examples(s):

          $(deriveJSON defaultOptions{} ''Bad) -- not ok, no fields selected for update of defaultOptions

         Test cases: th/T12788
      -}
      TcRnEmptyRecordUpdate :: TcRnMessage

      {-| TcRnIllegalFieldPunning is an error that occurs whenever
          field punning is used without the 'NamedFieldPuns' extension enabled.

          Examples(s):

          data Foo = Foo { a :: Int }

          foo :: Foo -> Int
          foo Foo{a} = a  -- Not ok, punning used without extension.

         Test cases: parser/should_fail/RecordDotSyntaxFail12
      -}
      TcRnIllegalFieldPunning :: !(Located RdrName) -> TcRnMessage

      {-| TcRnIllegalWildcardsInRecord is an error that occurs whenever
          wildcards (..) are used in a record without the relevant
          extension being enabled.

          Examples(s):

          data Foo = Foo { a :: Int }

          foo :: Foo -> Int
          foo Foo{..} = a  -- Not ok, wildcards used without extension.

         Test cases: parser/should_fail/RecordWildCardsFail
      -}
      TcRnIllegalWildcardsInRecord :: !RecordFieldPart -> TcRnMessage

      {-| TcRnIllegalWildcardInType is an error that occurs
          when a wildcard appears in a type in a location in which
          wildcards aren't allowed.

          Examples:

            Type synonyms:

              type T = _

            Class declarations and instances:

              class C _
              instance C _

            Standalone kind signatures:

              type D :: _
              data D

          Test cases:
            ExtraConstraintsWildcardInTypeSplice2
            ExtraConstraintsWildcardInTypeSpliceUsed
            ExtraConstraintsWildcardNotLast
            ExtraConstraintsWildcardTwice
            NestedExtraConstraintsWildcard
            NestedNamedExtraConstraintsWildcard
            PartialClassMethodSignature
            PartialClassMethodSignature2
            T12039
            T13324_fail1
            UnnamedConstraintWildcard1
            UnnamedConstraintWildcard2
            WildcardInADT1
            WildcardInADT2
            WildcardInADT3
            WildcardInADTContext1
            WildcardInDefault
            WildcardInDefaultSignature
            WildcardInDeriving
            WildcardInForeignExport
            WildcardInForeignImport
            WildcardInGADT1
            WildcardInGADT2
            WildcardInInstanceHead
            WildcardInInstanceSig
            WildcardInNewtype
            WildcardInPatSynSig
            WildcardInStandaloneDeriving
            WildcardInTypeFamilyInstanceRHS
            WildcardInTypeSynonymRHS
            saks_fail003
            T15433a
      -}
      TcRnIllegalWildcardInType
        :: Maybe Name
            -- ^ the wildcard name, or 'Nothing' for an anonymous wildcard
        -> !BadAnonWildcardContext
        -> TcRnMessage

      {-| TcRnIllegalNamedWildcardInTypeArgument is an error that occurs
          when a named wildcard is used in a required type argument.

          Example:

            vfun :: forall (a :: k) -> ()
            x = vfun _nwc
            --       ^^^^
            -- named wildcards not allowed in type arguments

          Test cases:
            T23738_fail_wild
      -}
      TcRnIllegalNamedWildcardInTypeArgument
        :: RdrName
        -> TcRnMessage

      {- TcRnIllegalImplicitTyVarInTypeArgument is an error raised
         when a type variable is implicitly quantified in a required type argument.

         Example:
           vfun :: forall (a :: k) -> ()
           x = vfun (Nothing :: Maybe a)
           --                        ^^^
           -- implicit quantification not allowed in type arguments

      -}
      TcRnIllegalImplicitTyVarInTypeArgument
        :: RdrName
        -> TcRnMessage

      {-| TcRnDuplicateFieldName is an error that occurs whenever
          there are duplicate field names in a single record.

          Examples(s):

            data R = MkR { x :: Int, x :: Bool }
            f r = r { x = 3, x = 4 }

         Test cases: T21959.
      -}
      TcRnDuplicateFieldName :: !RecordFieldPart -> NE.NonEmpty RdrName -> TcRnMessage

      {-| TcRnIllegalViewPattern is an error that occurs whenever
          the ViewPatterns syntax is used but the ViewPatterns language extension
          is not enabled.

          Examples(s):
          data Foo = Foo { a :: Int }

          foo :: Foo -> Int
          foo (a -> l) = l -- not OK, the 'ViewPattern' extension is not enabled.

         Test cases: parser/should_fail/ViewPatternsFail
      -}
      TcRnIllegalViewPattern :: !(Pat GhcPs) -> TcRnMessage

      {-| TcRnCharLiteralOutOfRange is an error that occurs whenever
          a character is out of range.

          Examples(s): None

         Test cases: None
      -}
      TcRnCharLiteralOutOfRange :: !Char -> TcRnMessage

      {-| TcRnNegativeNumTypeLiteral is an error that occurs whenever
          a type-level number literal is negative.

          type Neg = -1

         Test cases: th/T8412
                     typecheck/should_fail/T8306
      -}
      TcRnNegativeNumTypeLiteral :: HsTyLit GhcPs -> TcRnMessage

      {-| TcRnIllegalWildcardsInConstructor is an error that occurs whenever
          the record wildcards '..' are used inside a constructor without labeled fields.

          Examples(s): None

         Test cases:
           rename/should_fail/T9815.hs
           rename/should_fail/T9815b.hs
           rename/should_fail/T9815ghci.hs
           rename/should_fail/T9815bghci.hs
      -}
      TcRnIllegalWildcardsInConstructor :: !Name -> TcRnMessage

      {-| TcRnIgnoringAnnotations is a warning that occurs when the source code
          contains annotation pragmas but the platform in use does not support an
          external interpreter such as GHCi and therefore the annotations are ignored.

          Example(s): None

         Test cases: None
      -}
      TcRnIgnoringAnnotations :: [LAnnDecl GhcRn] -> TcRnMessage

      {-| TcRnAnnotationInSafeHaskell is an error that occurs if annotation pragmas
          are used in conjunction with Safe Haskell.

          Example(s): None

         Test cases: annotations/should_fail/T10826
      -}
      TcRnAnnotationInSafeHaskell :: TcRnMessage

      {-| TcRnInvalidTypeApplication is an error that occurs when a visible type application
          is used with an expression that does not accept "specified" type arguments.

          Example(s):
          foo :: forall {a}. a -> a
          foo x = x
          bar :: ()
          bar = let x = foo @Int 42
                in ()

         Test cases: overloadedrecflds/should_fail/overloadedlabelsfail03
                     typecheck/should_fail/ExplicitSpecificity1
                     typecheck/should_fail/ExplicitSpecificity10
                     typecheck/should_fail/ExplicitSpecificity2
                     typecheck/should_fail/T17173
                     typecheck/should_fail/VtaFail
      -}
      TcRnInvalidTypeApplication :: Type -> LHsWcType GhcRn -> TcRnMessage

      {-| TcRnTagToEnumMissingValArg is an error that occurs when the 'tagToEnum#'
          function is not applied to a single value argument.

          Example(s):
          tagToEnum# 1 2

         Test cases: None
      -}
      TcRnTagToEnumMissingValArg :: TcRnMessage

      {-| TcRnTagToEnumUnspecifiedResTy is an error that occurs when the 'tagToEnum#'
          function is not given a concrete result type.

          Example(s):
          foo :: forall a. a
          foo = tagToEnum# 0#

         Test cases: typecheck/should_fail/tcfail164
      -}
      TcRnTagToEnumUnspecifiedResTy :: Type -> TcRnMessage

      {-| TcRnTagToEnumResTyNotAnEnum is an error that occurs when the 'tagToEnum#'
          function is given a result type that is not an enumeration type.

          Example(s):
          foo :: Int -- not an enumeration TyCon
          foo = tagToEnum# 0#

         Test cases: typecheck/should_fail/tcfail164
      -}
      TcRnTagToEnumResTyNotAnEnum :: Type -> TcRnMessage

      {-| TcRnTagToEnumResTyTypeData is an error that occurs when the 'tagToEnum#'
          function is given a result type that is headed by a @type data@ type, as
          the data constructors of a @type data@ do not exist at the term level.

          Example(s):
          type data Letter = A | B | C

          foo :: Letter
          foo = tagToEnum# 0#

         Test cases: type-data/should_fail/TDTagToEnum.hs
      -}
      TcRnTagToEnumResTyTypeData :: Type -> TcRnMessage

      {-| TcRnArrowIfThenElsePredDependsOnResultTy is an error that occurs when the
          predicate type of an ifThenElse expression in arrow notation depends on
          the type of the result.

          Example(s): None

         Test cases: None
      -}
      TcRnArrowIfThenElsePredDependsOnResultTy :: TcRnMessage

      {-| TcRnIllegalHsBootOrSigDecl is an error that occurs when an hs-boot file
          contains declarations that are not allowed, such as bindings.

          Examples:

            -- A.hs-boot
            f :: Int -> Int
            f x = 2 * x -- binding not allowed

            -- B.hs-boot
            type family F a where { F Int = Bool }
              -- type family equations not allowed

            -- C.hsig
            bar :: Int -> Int
            {-# RULES forall x. bar x = x #-} -- RULES not allowed

         Test cases:

           - bindings: T19781
           - class instance body: none
           - type family instance: HsBootFam
           - splice: none
           - foreign declaration: none
           - default declaration: none
           - RULEs: none
      -}
      TcRnIllegalHsBootOrSigDecl :: !HsBootOrSig -> !BadBootDecls -> TcRnMessage

      {-| TcRnBootMismatch is a family of errors that occur when there is a
          mismatch between the hs-boot and hs files.

         Examples:

           -- A.hs-boot
           foo :: Int -> Bool
           data D = MkD

           -- A.hs
           foo :: Int -> Char
           foo = chr

           data D = MkD Int

          Test cases:

            - missing export: bkpcabal06, bkpfail{01,05,09,16,35}, rnfail{047,055}
            - missing definition: none
            - missing instance: T14075
            - mismatch in exports: bkpfail{03,19}
            - conflicting definitions: bkpcabal02,
               bkpfail{04,06,07,10,12,133,14,15,17,22,23,25,26,27,41,42,45,47,50,52,53,54},
               T19244{a,b}, T23344, ClosedFam3, rnfail055
      -}
      TcRnBootMismatch :: !HsBootOrSig -> !BootMismatch -> TcRnMessage

      {-| TcRnRecursivePatternSynonym is an error that occurs when a pattern synonym
          is defined in terms of itself, either directly or indirectly.

          Example(s):
          pattern A = B
          pattern B = A

         Test cases: patsyn/should_fail/T16900
      -}
      TcRnRecursivePatternSynonym :: LHsBinds GhcRn -> TcRnMessage

      {-| TcRnPartialTypeSigTyVarMismatch is an error that occurs when a partial type signature
          attempts to unify two different types.

          Example(s):
          f :: a -> b -> _
          f x y = [x, y]

         Test cases: partial-sigs/should_fail/T14449
      -}
      TcRnPartialTypeSigTyVarMismatch
        :: Name -- ^ first type variable
        -> Name -- ^ second type variable
        -> Name -- ^ function name
        -> LHsSigWcType GhcRn -> TcRnMessage

      {-| TcRnPartialTypeSigBadQuantifier is an error that occurs when a type variable
          being quantified over in the partial type signature of a function gets unified
          with a type that is free in that function's context.

          Example(s):
          foo :: Num a => a -> a
          foo xxx = g xxx
            where
              g :: forall b. Num b => _ -> b
              g y = xxx + y

         Test cases: partial-sig/should_fail/T14479
      -}
      TcRnPartialTypeSigBadQuantifier
        :: Name   -- ^ user-written name of type variable being quantified
        -> Name   -- ^ function name
        -> Maybe Type   -- ^ type the variable unified with, if known
        -> LHsSigWcType GhcRn  -- ^ partial type signature
        -> TcRnMessage

      {-| TcRnMissingSignature is a warning that occurs when a top-level binding
          or a pattern synonym does not have a type signature.

          Controlled by the flags:
            -Wmissing-signatures
            -Wmissing-exported-signatures
            -Wmissing-pattern-synonym-signatures
            -Wmissing-exported-pattern-synonym-signatures
            -Wmissing-kind-signatures
            -Wmissing-poly-kind-signatures

          Test cases:
            T11077 (top-level bindings)
            T12484 (pattern synonyms)
            T19564 (kind signatures)
      -}
      TcRnMissingSignature :: MissingSignature
                           -> Exported
                           -> TcRnMessage

      {-| TcRnPolymorphicBinderMissingSig is a warning controlled by -Wmissing-local-signatures
          that occurs when a local polymorphic binding lacks a type signature.

          Example(s):
          id a = a

         Test cases: warnings/should_compile/T12574
      -}
      TcRnPolymorphicBinderMissingSig :: Name -> Type -> TcRnMessage

      {-| TcRnOverloadedSig is an error that occurs when a binding group conflicts
          with the monomorphism restriction.

          Example(s):
          data T a = T a
          mono = ... where
            x :: Applicative f => f a
            T x = ...

         Test cases: typecheck/should_compile/T11339
      -}
      TcRnOverloadedSig :: TcIdSig -> TcRnMessage

      {-| TcRnTupleConstraintInst is an error that occurs whenever an instance
          for a tuple constraint is specified.

          Examples(s):
            class C m a
            class D m a
            f :: (forall a. Eq a => (C m a, D m a)) => m a
            f = undefined

          Test cases: quantified-constraints/T15334
      -}
      TcRnTupleConstraintInst :: !Class -> TcRnMessage

      {-| TcRnUserTypeError is an error that occurs due to a user's custom type error,
          which can be triggered by adding a `TypeError` constraint in a type signature
          or typeclass instance.

          Examples(s):
            f :: TypeError (Text "This is a type error")
            f = undefined

          Test cases: typecheck/should_fail/CustomTypeErrors02
                      typecheck/should_fail/CustomTypeErrors03
      -}
      TcRnUserTypeError :: !Type -> TcRnMessage

      {-| TcRnConstraintInKind is an error that occurs whenever a constraint is specified
          in a kind.

          Examples(s):
            data Q :: Eq a => Type where {}

          Test cases: dependent/should_fail/T13895
                      polykinds/T16263
                      saks/should_fail/saks_fail004
                      typecheck/should_fail/T16059a
                      typecheck/should_fail/T18714
      -}
      TcRnConstraintInKind :: !Type -> TcRnMessage

      {-| TcRnUnboxedTupleTypeFuncArg is an error that occurs whenever an unboxed tuple
          or unboxed sum type is specified as a function argument, when the appropriate
          extension (`-XUnboxedTuples` or `-XUnboxedSums`) isn't enabled.

          Examples(s):
            -- T15073.hs
            import T15073a
            newtype Foo a = MkFoo a
              deriving P

            -- T15073a.hs
            class P a where
              p :: a -> (# a #)

          Test cases: deriving/should_fail/T15073.hs
                      deriving/should_fail/T15073a.hs
                      typecheck/should_fail/T16059d
      -}
      TcRnUnboxedTupleOrSumTypeFuncArg
        :: UnboxedTupleOrSum -- ^ whether this is an unboxed tuple or an unboxed sum
        -> !Type
        -> TcRnMessage

      {-| TcRnLinearFuncInKind is an error that occurs whenever a linear function is
          specified in a kind.

          Examples(s):
            data A :: * %1 -> *

          Test cases: linear/should_fail/LinearKind
                      linear/should_fail/LinearKind2
                      linear/should_fail/LinearKind3
      -}
      TcRnLinearFuncInKind :: !Type -> TcRnMessage

      {-| TcRnForAllEscapeError is an error that occurs whenever a quantified type's kind
          mentions quantified type variable.

          Examples(s):
            type T :: TYPE (BoxedRep l)
            data T = MkT

          Test cases: unlifted-datatypes/should_fail/UnlDataNullaryPoly
      -}
      TcRnForAllEscapeError :: !Type -> !Kind -> TcRnMessage

      {-| TcRnVDQInTermType is an error that occurs whenever a visible dependent quantification
          is specified in the type of a term.

          Examples(s):
            a = (undefined :: forall k -> k -> Type) @Int

          Test cases: dependent/should_fail/T15859
                      dependent/should_fail/T16326_Fail1
                      dependent/should_fail/T16326_Fail2
                      dependent/should_fail/T16326_Fail3
                      dependent/should_fail/T16326_Fail4
                      dependent/should_fail/T16326_Fail5
                      dependent/should_fail/T16326_Fail6
                      dependent/should_fail/T16326_Fail7
                      dependent/should_fail/T16326_Fail8
                      dependent/should_fail/T16326_Fail9
                      dependent/should_fail/T16326_Fail10
                      dependent/should_fail/T16326_Fail11
                      dependent/should_fail/T16326_Fail12
                      dependent/should_fail/T17687
                      dependent/should_fail/T18271
      -}
      TcRnVDQInTermType :: !(Maybe Type) -> TcRnMessage

      {-| TcRnBadQuantPredHead is an error that occurs whenever a quantified predicate
          lacks a class or type variable head.

          Examples(s):
            class (forall a. A t a => A t [a]) => B t where
              type A t a :: Constraint

          Test cases: quantified-constraints/T16474
      -}
      TcRnBadQuantPredHead :: !Type -> TcRnMessage

      {-| TcRnIllegalTupleConstraint is an error that occurs whenever an illegal tuple
          constraint is specified.

          Examples(s):
            g :: ((Show a, Num a), Eq a) => a -> a
            g = undefined

          Test cases: typecheck/should_fail/tcfail209a
      -}
      TcRnIllegalTupleConstraint :: !Type -> TcRnMessage

      {-| TcRnNonTypeVarArgInConstraint is an error that occurs whenever a non type-variable
          argument is specified in a constraint.

          Examples(s):
            data T
            instance Eq Int => Eq T

          Test cases: ghci/scripts/T13202
                      ghci/scripts/T13202a
                      polykinds/T12055a
                      typecheck/should_fail/T10351
                      typecheck/should_fail/T19187
                      typecheck/should_fail/T6022
                      typecheck/should_fail/T8883
      -}
      TcRnNonTypeVarArgInConstraint :: !Type -> TcRnMessage

      {-| TcRnIllegalImplicitParam is an error that occurs whenever an illegal implicit
          parameter is specified.

          Examples(s):
            type Bla = ?x::Int
            data T = T
            instance Bla => Eq T

          Test cases: polykinds/T11466
                      typecheck/should_fail/T8912
                      typecheck/should_fail/tcfail041
                      typecheck/should_fail/tcfail211
                      typecheck/should_fail/tcrun045
      -}
      TcRnIllegalImplicitParam :: !Type -> TcRnMessage

      {-| TcRnIllegalConstraintSynonymOfKind is an error that occurs whenever an illegal constraint
          synonym of kind is specified.

          Examples(s):
            type Showish = Show
            f :: (Showish a) => a -> a
            f = undefined

          Test cases: typecheck/should_fail/tcfail209
      -}
      TcRnIllegalConstraintSynonymOfKind :: !Type -> TcRnMessage

      {-| TcRnOversaturatedVisibleKindArg is an error that occurs whenever an illegal oversaturated
          visible kind argument is specified.

          Examples(s):
            type family
              F2 :: forall (a :: Type). Type where
              F2 @a = Maybe a

          Test cases: typecheck/should_fail/T15793
                      typecheck/should_fail/T16255
      -}
      TcRnOversaturatedVisibleKindArg :: !Type -> TcRnMessage

      {-| TcRnForAllRankErr is an error that occurs whenever an illegal ranked type
          is specified.

          Examples(s):
            foo :: (a,b) -> (a~b => t) -> (a,b)
            foo p x = p

          Test cases:
            - ghci/should_run/T15806
            - indexed-types/should_fail/SimpleFail15
            - typecheck/should_fail/T11355
            - typecheck/should_fail/T12083a
            - typecheck/should_fail/T12083b
            - typecheck/should_fail/T16059c
            - typecheck/should_fail/T16059e
            - typecheck/should_fail/T17213
            - typecheck/should_fail/T18939_Fail
            - typecheck/should_fail/T2538
            - typecheck/should_fail/T5957
            - typecheck/should_fail/T7019
            - typecheck/should_fail/T7019a
            - typecheck/should_fail/T7809
            - typecheck/should_fail/T9196
            - typecheck/should_fail/tcfail127
            - typecheck/should_fail/tcfail184
            - typecheck/should_fail/tcfail196
            - typecheck/should_fail/tcfail197
      -}
      TcRnForAllRankErr :: !Rank -> !Type -> TcRnMessage

      {-| TcRnSimplifiableConstraint is a warning triggered by the occurrence of
          a simplifiable constraint in a context, when MonoLocalBinds is not enabled.

          Examples(s):
            simplifiableEq :: Eq (a, a) => a -> a -> Bool
            simplifiableEq = undefined

          Test cases:
            - indexed-types/should_compile/T15322
            - partial-sigs/should_compile/SomethingShowable
            - typecheck/should_compile/T13526
      -}
      TcRnSimplifiableConstraint :: !PredType -> !InstanceWhat -> TcRnMessage

      {-| TcRnArityMismatch is an error that occurs when a type constructor is supplied with
          fewer arguments than required.

          Examples(s):
            f Left = undefined

          Test cases:
            - backpack/should_fail/bkpfail25.bkp
            - ghci/should_fail/T16013
            - ghci/should_fail/T16287
            - indexed-types/should_fail/BadSock
            - indexed-types/should_fail/T9433
            - module/mod60
            - ndexed-types/should_fail/T2157
            - parser/should_fail/ParserNoBinaryLiterals2
            - parser/should_fail/ParserNoBinaryLiterals3
            - patsyn/should_fail/T12819
            - polykinds/T10516
            - typecheck/should_fail/T12124
            - typecheck/should_fail/T15954
            - typecheck/should_fail/T16874
            - typecheck/should_fail/tcfail100
            - typecheck/should_fail/tcfail101
            - typecheck/should_fail/tcfail107
            - typecheck/should_fail/tcfail129
            - typecheck/should_fail/tcfail187
      -}
      TcRnArityMismatch :: !TyThing
                        -> !Arity -- ^ expected arity
                        -> !Arity -- ^ actual arity
                        -> TcRnMessage

      {-| TcRnIllegalClassInstance is a collection of diagnostics that arise
          from an invalid class or family instance declaration.

          See t'IllegalInstanceReason'.
      -}
      TcRnIllegalInstance :: IllegalInstanceReason -> TcRnMessage

      {-| TcRnMonomorphicBindings is a warning (controlled by -Wmonomorphism-restriction)
          that arises when the monomorphism restriction applies to the given bindings.

          Examples(s):
            {-# OPTIONS_GHC -Wmonomorphism-restriction #-}

            bar = 10

            foo :: Int
            foo = bar

            main :: IO ()
            main = print foo

          The example above emits the warning (for 'bar'), because without monomorphism
          restriction the inferred type for 'bar' is 'bar :: Num p => p'. This warning tells us
          that /if/ we were to enable '-XMonomorphismRestriction' we would make 'bar'
          less polymorphic, as its type would become 'bar :: Int', so GHC warns us about that.

          Test cases: typecheck/should_compile/T13785
      -}
      TcRnMonomorphicBindings :: [Name] -> TcRnMessage

      {-| TcRnOrphanInstance is a warning (controlled by -Worphans) that arises when
          a typeclass instance or family instance is an \"orphan\", i.e. if it
          appears in a module in which neither the class/family nor the type being
          instanced are declared in the same module.

          Examples(s): None

          Test cases: warnings/should_compile/T9178
                      typecheck/should_compile/T4912
      -}
      TcRnOrphanInstance :: Either ClsInst FamInst -> TcRnMessage

      {-| TcRnFunDepConflict is an error that occurs when there are functional dependencies
          conflicts between instance declarations.

          Examples(s): None

          Test cases: typecheck/should_fail/T2307
                      typecheck/should_fail/tcfail096
                      typecheck/should_fail/tcfail202
      -}
      TcRnFunDepConflict :: !UnitState -> NE.NonEmpty ClsInst -> TcRnMessage

      {-| TcRnDupInstanceDecls is an error that occurs when there are duplicate instance
          declarations.

          Examples(s):
            class Foo a where
              foo :: a -> Int

            instance Foo Int where
              foo = id

            instance Foo Int where
              foo = const 42

          Test cases: cabal/T12733/T12733
                      typecheck/should_fail/tcfail035
                      typecheck/should_fail/tcfail023
                      backpack/should_fail/bkpfail18
                      typecheck/should_fail/TcNullaryTCFail
                      typecheck/should_fail/tcfail036
                      typecheck/should_fail/tcfail073
                      module/mod51
                      module/mod52
                      module/mod44
      -}
      TcRnDupInstanceDecls :: !UnitState -> NE.NonEmpty ClsInst -> TcRnMessage

      {-| TcRnConflictingFamInstDecls is an error that occurs when there are conflicting
          family instance declarations.

          Examples(s): None.

          Test cases: indexed-types/should_fail/ExplicitForAllFams4b
                      indexed-types/should_fail/NoGood
                      indexed-types/should_fail/Over
                      indexed-types/should_fail/OverDirectThisMod
                      indexed-types/should_fail/OverIndirectThisMod
                      indexed-types/should_fail/SimpleFail11a
                      indexed-types/should_fail/SimpleFail11b
                      indexed-types/should_fail/SimpleFail11c
                      indexed-types/should_fail/SimpleFail11d
                      indexed-types/should_fail/SimpleFail2a
                      indexed-types/should_fail/SimpleFail2b
                      indexed-types/should_fail/T13092/T13092
                      indexed-types/should_fail/T13092c/T13092c
                      indexed-types/should_fail/T14179
                      indexed-types/should_fail/T2334A
                      indexed-types/should_fail/T2677
                      indexed-types/should_fail/T3330b
                      indexed-types/should_fail/T4246
                      indexed-types/should_fail/T7102a
                      indexed-types/should_fail/T9371
                      polykinds/T7524
                      typecheck/should_fail/UnliftedNewtypesOverlap
      -}
      TcRnConflictingFamInstDecls :: NE.NonEmpty FamInst -> TcRnMessage

      {-| TcRnFamInstNotInjective is a collection of errors that arise from
          a type family equation violating the injectivity annotation.

          See 'InjectivityErrReason'.
      -}
      TcRnFamInstNotInjective :: InjectivityErrReason -- ^ the violation
                              -> TyCon -- ^ the family 'TyCon'
                              -> NE.NonEmpty CoAxBranch -- ^ the family equations
                              -> TcRnMessage

      {-| TcRnBangOnUnliftedType is a warning (controlled by -Wredundant-strictness-flags) that
          occurs when a strictness annotation is applied to an unlifted type.

          Example(s):
          data T = MkT !Int# -- Strictness flag has no effect on unlifted types

         Test cases: typecheck/should_compile/T20187a
                     typecheck/should_compile/T20187b
      -}
      TcRnBangOnUnliftedType :: !Type -> TcRnMessage

      {-| TcRnLazyBangOnUnliftedType is a warning (controlled by -Wredundant-strictness-flags) that
          occurs when a lazy annotation is applied to an unlifted type.

          Example(s):
          data T = MkT ~Int# -- Lazy flag has no effect on unlifted types

         Test cases: typecheck/should_compile/T21951a
                     typecheck/should_compile/T21951b
      -}
      TcRnLazyBangOnUnliftedType :: !Type -> TcRnMessage

      {-| TcRnMultipleDefaultDeclarations is an error that occurs when a module has
          more than one default declaration.

          Example:
          default (Integer, Int)
          default (Double, Float) -- 2nd default declaration not allowed

         Text cases: module/mod58
      -}
      TcRnMultipleDefaultDeclarations :: [LDefaultDecl GhcRn] -> TcRnMessage

      {-| TcRnBadDefaultType is an error that occurs when a type used in a default
          declaration does not have an instance for any of the applicable classes.

          Example(s):
          data Foo
          default (Foo)

         Test cases: typecheck/should_fail/T11974b
      -}
      TcRnBadDefaultType :: Type -> [Class] -> TcRnMessage

      {-| TcRnPatSynBundledWithNonDataCon is an error that occurs when a module's
          export list bundles a pattern synonym with a type that is not a proper
          `data` or `newtype` construction.

          Example(s):
          module Foo (MyClass(.., P)) where
          pattern P = Nothing
          class MyClass a where
            foo :: a -> Int

         Test cases: patsyn/should_fail/export-class
      -}
      TcRnPatSynBundledWithNonDataCon :: TcRnMessage

      {-| TcRnPatSynBundledWithWrongType is an error that occurs when the export list
          of a module has a pattern synonym bundled with a type that does not match
          the type of the pattern synonym.

          Example(s):
          module Foo (R(P,x)) where
          data Q = Q Int
          data R = R
          pattern P{x} = Q x

         Text cases: patsyn/should_fail/export-ps-rec-sel
                     patsyn/should_fail/export-type-synonym
                     patsyn/should_fail/export-type
      -}
      TcRnPatSynBundledWithWrongType :: Type -> Type -> TcRnMessage

      {-| TcRnDupeModuleExport is a warning controlled by @-Wduplicate-exports@ that
          occurs when a module appears more than once in an export list.

          Example(s):
          module Foo (module Bar, module Bar)
          import Bar

         Text cases: None
      -}
      TcRnDupeModuleExport :: ModuleName -> TcRnMessage

      {-| TcRnExportedModNotImported is an error that occurs when an export list
          contains a module that is not imported.

          Example(s): None

         Text cases: module/mod135
                     module/mod8
                     rename/should_fail/rnfail028
                     backpack/should_fail/bkpfail48
      -}
      TcRnExportedModNotImported :: ModuleName -> TcRnMessage

      {-| TcRnNullExportedModule is a warning controlled by -Wdodgy-exports that occurs
          when an export list contains a module that has no exports.

          Example(s):
          module Foo (module Bar) where
          import Bar ()

         Test cases: None
      -}
      TcRnNullExportedModule :: ModuleName -> TcRnMessage

      {-| TcRnMissingExportList is a warning controlled by -Wmissing-export-lists that
          occurs when a module does not have an explicit export list.

          Example(s): None

         Test cases: typecheck/should_fail/MissingExportList03
      -}
      TcRnMissingExportList :: ModuleName -> TcRnMessage

      {-| TcRnExportHiddenComponents is an error that occurs when an export contains
          constructor or class methods that are not visible.

          Example(s): None

         Test cases: None
      -}
      TcRnExportHiddenComponents :: IE GhcPs -> TcRnMessage

      {-| TcRnDuplicateExport is a warning (controlled by -Wduplicate-exports) that occurs
          when an identifier appears in an export list more than once.

          Example(s): None

         Test cases: module/MultiExport
                     module/mod128
                     module/mod14
                     module/mod5
                     overloadedrecflds/should_fail/DuplicateExports
                     patsyn/should_compile/T11959
      -}
      TcRnDuplicateExport :: GlobalRdrElt -> IE GhcPs -> IE GhcPs -> TcRnMessage

      {-| TcRnExportedParentChildMismatch is an error that occurs when an export is
          bundled with a parent that it does not belong to

          Example(s):
          module Foo (T(a)) where
          data T
          a = True

         Test cases: module/T11970
                     module/T11970B
                     module/mod17
                     module/mod3
                     overloadedrecflds/should_fail/NoParent
      -}
      TcRnExportedParentChildMismatch :: Name -- ^ parent
                                      -> TyThing
                                      -> Name -- ^ child
                                      -> [Name] -> TcRnMessage

      {-| TcRnConflictingExports is an error that occurs when different identifiers that
          have the same name are being exported by a module.

          Example(s):
          module Foo (Bar.f, module Baz) where
          import qualified Bar (f)
          import Baz (f)

         Test cases: module/mod131
                     module/mod142
                     module/mod143
                     module/mod144
                     module/mod145
                     module/mod146
                     module/mod150
                     module/mod155
                     overloadedrecflds/should_fail/T14953
                     overloadedrecflds/should_fail/overloadedrecfldsfail10
                     rename/should_fail/rnfail029
                     rename/should_fail/rnfail040
                     typecheck/should_fail/T16453E2
                     typecheck/should_fail/tcfail025
                     typecheck/should_fail/tcfail026
      -}
      TcRnConflictingExports
        :: OccName      -- ^ Occurrence name shared by both exports
        -> GlobalRdrElt -- ^ First export
        -> IE GhcPs     -- ^ Export decl of first export
        -> GlobalRdrElt -- ^ Second export
        -> IE GhcPs     -- ^ Export decl of second export
        -> TcRnMessage

      {-| TcRnDuplicateFieldExport is an error that occurs when a module exports
          multiple record fields with the same name, without enabling
          DuplicateRecordFields.

          Example:

          module M1 where
            data D1 = MkD1 { foo :: Int }
          module M2 where
            data D2 = MkD2 { foo :: Int }
          module M ( D1(..), D2(..) ) where
            import module M1
            import module M2

         Test case: overloadedrecflds/should_fail/overloadedrecfldsfail10
      -}
      TcRnDuplicateFieldExport
        :: (GlobalRdrElt, IE GhcPs)
        -> NE.NonEmpty (GlobalRdrElt, IE GhcPs)
        -> TcRnMessage

      {-| TcRnAmbiguousRecordUpdate is a warning, controlled by -Wambiguous-fields,
          which occurs when a user relies on the type-directed disambiguation
          mechanism to disambiguate a record update. This will not be supported by
          -XDuplicateRecordFields in future releases.

          Example(s):

            data Person  = MkPerson  { personId :: Int, name :: String }
            data Address = MkAddress { personId :: Int, address :: String }
            bad1 x = x { personId = 4 } :: Person -- ambiguous
            bad2 (x :: Person) = x { personId = 4 } -- ambiguous
            good x = (x :: Person) { personId = 4 } -- not ambiguous

         Test cases: overloadedrecflds/should_fail/overloadedrecfldsfail06
      -}
      TcRnAmbiguousRecordUpdate
        :: HsExpr GhcRn -- ^ Field update
        -> TyCon -- ^ Record type
        -> TcRnMessage

      {-| TcRnMissingFields is a warning controlled by -Wmissing-fields occurring
          when the intialisation of a record is missing one or more (lazy) fields.

          Example(s):
          data Rec = Rec { a :: Int, b :: String, c :: Bool }
          x = Rec { a = 1, b = "two" } -- missing field 'c'

         Test cases: deSugar/should_compile/T13870
                     deSugar/should_compile/ds041
                     patsyn/should_compile/T11283
                     rename/should_compile/T5334
                     rename/should_compile/T12229
                     rename/should_compile/T5892a
                     warnings/should_fail/WerrorFail2
      -}
      TcRnMissingFields :: ConLike -> [(FieldLabelString, TcType)] -> TcRnMessage

      {-| TcRnFieldUpdateInvalidType is an error occurring when an updated field's
          type mentions something that is outside the universally quantified variables
          of the data constructor, such as an existentially quantified type.

          Example(s):
          data X = forall a. MkX { f :: a }
          x = (MkX ()) { f = False }

          Test cases: patsyn/should_fail/records-exquant
                      typecheck/should_fail/T3323
      -}
      TcRnFieldUpdateInvalidType :: [(FieldLabelString,TcType)] -> TcRnMessage

      {-| TcRnMissingStrictFields is an error occurring when a record field marked
         as strict is omitted when constructing said record.

         Example(s):
         data R = R { strictField :: !Bool, nonStrict :: Int }
         x = R { nonStrict = 1 }

        Test cases: typecheck/should_fail/T18869
                    typecheck/should_fail/tcfail085
                    typecheck/should_fail/tcfail112
      -}
      TcRnMissingStrictFields :: ConLike -> [(FieldLabelString, TcType)] -> TcRnMessage

      {-| TcRnAmbiguousFieldInUpdate is an error that occurs when a field in a
          record update clashes with another field or top-level function of the
          same name, and the user hasn't enabled -XDisambiguateRecordFields.

          Example:

            {-# LANGUAGE NoFieldSelectors #-}
            {-# LANGUAGE NoDisambiguateRecordFields #-}
            module M where

              data A = MkA { fld :: Int }

              fld :: Bool
              fld = False

              f r = r { fld = 3 }

      -}
      TcRnAmbiguousFieldInUpdate :: (GlobalRdrElt, GlobalRdrElt, [GlobalRdrElt])
                                    -> TcRnMessage

      {-| TcRnBadRecordUpdate is an error when a regular (non-overloaded)
         record update cannot be pinned down to any one parent.

         The problem with the record update is stored in the 'BadRecordUpdateReason'
         field.

         Example(s):

           data R1 = R1 { x :: Int }
           data R2 = R2 { x :: Int }
           update r = r { x = 1 }
             -- ambiguous

           data R1 = R1 { x :: Int, y :: Int }
           data R2 = R2 { y :: Int, z :: Int }
           update r = r { x = 1, y = 2, z = 3 }
             -- no parent has all the fields

        Test cases: overloadedrecflds/should_fail/overloadedrecfldsfail01
                    overloadedrecflds/should_fail/overloadedrecfldsfail01
                    overloadedrecflds/should_fail/overloadedrecfldsfail14
      -}
      TcRnBadRecordUpdate :: [RdrName]
                             -- ^ the fields of the record update
                          -> BadRecordUpdateReason
                             -- ^ the reason this record update was rejected
                          -> TcRnMessage

      {-| TcRnStaticFormNotClosed is an error pertaining to terms that are marked static
         using the -XStaticPointers extension but which are not closed terms.

         Example(s):
         f x = static x

        Test cases: rename/should_fail/RnStaticPointersFail01
                    rename/should_fail/RnStaticPointersFail03
      -}
      TcRnStaticFormNotClosed :: Name -> NotClosedReason -> TcRnMessage

      {-| TcRnUselessTypeable is a warning (controlled by -Wderiving-typeable) that
          occurs when trying to derive an instance of the 'Typeable' class. Deriving
          'Typeable' is no longer necessary (hence the \"useless\") as all types
          automatically derive 'Typeable' in modern GHC versions.

          Example(s): None.

         Test cases: warnings/should_compile/DerivingTypeable
      -}
      TcRnUselessTypeable :: TcRnMessage

      {-| TcRnDerivingDefaults is a warning (controlled by -Wderiving-defaults) that
          occurs when both 'DeriveAnyClass' and 'GeneralizedNewtypeDeriving' are
          enabled, and therefore GHC defaults to 'DeriveAnyClass', which might not
          be what the user wants.

          Example(s): None.

         Test cases: typecheck/should_compile/T15839a
                     deriving/should_compile/T16179
      -}
      TcRnDerivingDefaults :: !Class -> TcRnMessage

      {-| TcRnNonUnaryTypeclassConstraint is an error that occurs when GHC
          encounters a non-unary constraint when trying to derive a typeclass.

          Example(s):
            class A
            deriving instance A
            data B deriving A  -- We cannot derive A, is not unary (i.e. 'class A a').

         Test cases: deriving/should_fail/T7959
                     deriving/should_fail/drvfail005
                     deriving/should_fail/drvfail009
                     deriving/should_fail/drvfail006
      -}
      TcRnNonUnaryTypeclassConstraint :: !(LHsSigType GhcRn) -> TcRnMessage

      {-| TcRnPartialTypeSignatures is a warning (controlled by -Wpartial-type-signatures)
          that occurs when a wildcard '_' is found in place of a type in a signature or a
          type class derivation

          Example(s):
            foo :: _ -> Int
            foo = ...

            deriving instance _ => Eq (Foo a)

         Test cases: dependent/should_compile/T11241
                     dependent/should_compile/T15076
                     dependent/should_compile/T14880-2
                     typecheck/should_compile/T17024
                     typecheck/should_compile/T10072
                     partial-sigs/should_fail/TidyClash2
                     partial-sigs/should_fail/Defaulting1MROff
                     partial-sigs/should_fail/WildcardsInPatternAndExprSig
                     partial-sigs/should_fail/T10615
                     partial-sigs/should_fail/T14584a
                     partial-sigs/should_fail/TidyClash
                     partial-sigs/should_fail/T11122
                     partial-sigs/should_fail/T14584
                     partial-sigs/should_fail/T10045
                     partial-sigs/should_fail/PartialTypeSignaturesDisabled
                     partial-sigs/should_fail/T10999
                     partial-sigs/should_fail/ExtraConstraintsWildcardInExpressionSignature
                     partial-sigs/should_fail/ExtraConstraintsWildcardInPatternSplice
                     partial-sigs/should_fail/WildcardInstantiations
                     partial-sigs/should_run/T15415
                     partial-sigs/should_compile/T10463
                     partial-sigs/should_compile/T15039a
                     partial-sigs/should_compile/T16728b
                     partial-sigs/should_compile/T15039c
                     partial-sigs/should_compile/T10438
                     partial-sigs/should_compile/SplicesUsed
                     partial-sigs/should_compile/T18008
                     partial-sigs/should_compile/ExprSigLocal
                     partial-sigs/should_compile/T11339a
                     partial-sigs/should_compile/T11670
                     partial-sigs/should_compile/WarningWildcardInstantiations
                     partial-sigs/should_compile/T16728
                     partial-sigs/should_compile/T12033
                     partial-sigs/should_compile/T15039b
                     partial-sigs/should_compile/T10403
                     partial-sigs/should_compile/T11192
                     partial-sigs/should_compile/T16728a
                     partial-sigs/should_compile/TypedSplice
                     partial-sigs/should_compile/T15039d
                     partial-sigs/should_compile/T11016
                     partial-sigs/should_compile/T13324_compile2
                     linear/should_fail/LinearPartialSig
                     polykinds/T14265
                     polykinds/T14172
      -}
      TcRnPartialTypeSignatures :: !SuggestPartialTypeSignatures -> !ThetaType -> TcRnMessage

      {-| TcRnCannotDeriveInstance is an error that occurs every time a typeclass instance
          can't be derived. The 'DeriveInstanceErrReason' will contain the specific reason
          this error arose.

          Example(s): None.

          Test cases: generics/T10604/T10604_no_PolyKinds
                      deriving/should_fail/drvfail009
                      deriving/should_fail/drvfail-functor2
                      deriving/should_fail/T10598_fail3
                      deriving/should_fail/deriving-via-fail2
                      deriving/should_fail/deriving-via-fail
                      deriving/should_fail/T16181
      -}
      TcRnCannotDeriveInstance :: !Class
                               -- ^ The typeclass we are trying to derive
                               -- an instance for
                               -> [Type]
                               -- ^ The typeclass arguments, if any.
                               -> !(Maybe (DerivStrategy GhcTc))
                               -- ^ The derivation strategy, if any.
                               -> !UsingGeneralizedNewtypeDeriving
                               -- ^ Is '-XGeneralizedNewtypeDeriving' enabled?
                               -> !DeriveInstanceErrReason
                               -- ^ The specific reason why we couldn't derive
                               -- an instance for the class.
                               -> TcRnMessage

      {-| TcRnLazyGADTPattern is an error that occurs when a user writes a nested
          GADT pattern match inside a lazy (~) pattern.

          Test case: gadt/lazypat
      -}
      TcRnLazyGADTPattern :: TcRnMessage

      {-| TcRnArrowProcGADTPattern is an error that occurs when a user writes a
          GADT pattern inside arrow proc notation.

          Test case: arrows/should_fail/arrowfail004.
      -}
      TcRnArrowProcGADTPattern :: TcRnMessage

      {-| TcRnCapturedTermName is a warning (controlled by -Wterm-variable-capture) that occurs
        when an implicitly quantified type variable's name is already used for a term.
        Example:
          a = 10
          f :: a -> a

        Test cases: T22513a T22513b T22513c T22513d T22513e T22513f T22513g T22513h T22513i
     -}
      TcRnCapturedTermName :: RdrName -> Either [GlobalRdrElt] Name -> TcRnMessage

      {-| TcRnTypeEqualityOutOfScope is a warning (controlled by -Wtype-equality-out-of-scope)
          that occurs when the type equality (a ~ b) is not in scope.

          Test case: warnings/should_compile/T18862b
      -}
      TcRnTypeEqualityOutOfScope :: TcRnMessage

      {-| TcRnTypeEqualityRequiresOperators is a warning (controlled by -Wtype-equality-requires-operators)
          that occurs when the type equality (a ~ b) is used without the TypeOperators extension.

          Example:
            {-# LANGUAGE NoTypeOperators #-}
            f :: (a ~ b) => a -> b

          Test case: T18862a
      -}
      TcRnTypeEqualityRequiresOperators :: TcRnMessage

      {-| TcRnIllegalTypeOperator is an error that occurs when a type operator
          is used without the TypeOperators extension.

          Example:
            {-# LANGUAGE NoTypeOperators #-}
            f :: Vec a n -> Vec a m -> Vec a (n + m)

          Test case: T12811
      -}
      TcRnIllegalTypeOperator :: !SDoc -> !RdrName -> TcRnMessage

      {-| TcRnIllegalTypeOperatorDecl is an error that occurs when a type or class
          operator is declared without the TypeOperators extension.

          See Note [Type and class operator definitions]

          Example:
            {-# LANGUAGE Haskell2010 #-}
            {-# LANGUAGE MultiParamTypeClasses #-}

            module T3265 where

            data a :+: b = Left a | Right b

            class a :*: b where {}

          Test cases: T3265, tcfail173
      -}
      TcRnIllegalTypeOperatorDecl :: !RdrName -> TcRnMessage

      {-| TcRnGADTMonoLocalBinds is a warning controlled by -Wgadt-mono-local-binds
          that occurs when pattern matching on a GADT when -XMonoLocalBinds is off.

          Example(s): None

          Test cases: T20485, T20485a
      -}
      TcRnGADTMonoLocalBinds :: TcRnMessage

      {-| The TcRnNotInScope constructor is used for various not-in-scope errors.
          See 'NotInScopeError' for more details. -}
      TcRnNotInScope :: NotInScopeError  -- ^ what the problem is
                     -> RdrName          -- ^ the name that is not in scope
                     -> [ImportError]    -- ^ import errors that are relevant
                     -> [GhcHint]        -- ^ hints, e.g. enable DataKinds to refer to a promoted data constructor
                     -> TcRnMessage

      {-| TcRnTermNameInType is an error that occurs when a term-level identifier
          is used in a type.

          Example:

            import qualified Prelude

            bad :: Prelude.fst (Bool, Float)
            bad = False

          Test cases: T21605{c,d}
      -}
      TcRnTermNameInType :: RdrName -> [GhcHint] -> TcRnMessage

      {-| TcRnUntickedPromotedThing is a warning (controlled with -Wunticked-promoted-constructors)
          that is triggered by an unticked occurrence of a promoted data constructor.

          Examples:

            data A = MkA
            type family F (a :: A) where { F MkA = Bool }

            type B = [ Int, Bool ]

          Test cases: T9778, T19984.
      -}
      TcRnUntickedPromotedThing :: UntickedPromotedThing
                                -> TcRnMessage

      {-| TcRnIllegalBuiltinSyntax is an error that occurs when built-in syntax appears
          in an unexpected location, e.g. as a data constructor or in a fixity declaration.

          Examples:

            infixl 5 :

            data P = (,)

          Test cases: rnfail042, T14907b, T15124, T15233.
      -}
      TcRnIllegalBuiltinSyntax :: SDoc -- ^ what kind of thing this is (a binding, fixity declaration, ...)
                               -> RdrName
                               -> TcRnMessage
        -- TODO: remove the SDoc argument.

      {-| TcRnWarnDefaulting is a warning (controlled by -Wtype-defaults)
          that is triggered whenever a Wanted typeclass constraint
          is solving through the defaulting of a type variable.

          Example:

            one = show 1
            -- We get Wanteds Show a0, Num a0, and default a0 to Integer.

          Test cases:
            none (which are really specific to defaulting),
            but see e.g. tcfail204.
       -}
      TcRnWarnDefaulting :: [Ct] -- ^ Wanted constraints in which defaulting occurred
                         -> Maybe TyVar -- ^ The type variable being defaulted
                         -> Type -- ^ The default type
                         -> TcRnMessage

      {-| TcRnIncorrectNameSpace is an error that occurs when a 'Name'
          is used in the incorrect 'NameSpace', e.g. a type constructor
          or class used in a term, or a term variable used in a type.

          Example:

            list2 = $( conE ''(:) `appE` litE (IntegerL 5) `appE` conE '[] )
            --              ^^^^^
            --              should use a single quotation tick, i.e. '(:)

          Test cases: T20884.
      -}
      TcRnIncorrectNameSpace :: Name
                             -> Bool -- ^ whether the error is happening
                                     -- in a Template Haskell tick
                                     -- (so we should give a Template Haskell hint)
                             -> TcRnMessage

      {-| TcRnForeignImportPrimExtNotSet is an error occurring when a foreign import
         is declared using the @prim@ calling convention without having turned on
         the -XGHCForeignImportPrim extension.

         Example(s):
         foreign import prim "foo" foo :: ByteArray# -> (# Int#, Int# #)

        Test cases: ffi/should_fail/T20116
      -}
      TcRnForeignImportPrimExtNotSet :: ForeignImport GhcRn -> TcRnMessage

      {-| TcRnForeignImportPrimSafeAnn is an error declaring that the safe/unsafe
         annotation should not be used with @prim@ foreign imports.

         Example(s):
         foreign import prim unsafe "my_primop_cmm" :: ...

        Test cases: None
      -}
      TcRnForeignImportPrimSafeAnn :: ForeignImport GhcRn -> TcRnMessage

      {-| TcRnForeignFunctionImportAsValue is an error explaining that foreign @value@
         imports cannot have function types.

         Example(s):
         foreign import capi "math.h value sqrt" f :: CInt -> CInt

        Test cases: ffi/should_fail/capi_value_function
      -}
      TcRnForeignFunctionImportAsValue :: ForeignImport GhcRn -> TcRnMessage

      {-| TcRnFunPtrImportWithoutAmpersand is a warning controlled by @-Wdodgy-foreign-imports@
         that informs the user of a possible missing @&@ in the declaration of a
         foreign import with a 'FunPtr' return type.

         Example(s):
         foreign import ccall "f" f :: FunPtr (Int -> IO ())

        Test cases: ffi/should_compile/T1357
      -}
      TcRnFunPtrImportWithoutAmpersand :: ForeignImport GhcRn -> TcRnMessage

      {-| TcRnIllegalForeignDeclBackend is an error occurring when a foreign import declaration
         is not compatible with the code generation backend being used.

         Example(s): None

        Test cases: None
      -}
      TcRnIllegalForeignDeclBackend
        :: Either (ForeignExport GhcRn) (ForeignImport GhcRn)
        -> Backend
        -> ExpectedBackends
        -> TcRnMessage

      {-| TcRnUnsupportedCallConv informs the user that the calling convention specified
         for a foreign export declaration is not compatible with the target platform.
         It is a warning controlled by @-Wunsupported-calling-conventions@ in the case of
         @stdcall@ but is otherwise considered an error.

         Example(s): None

        Test cases: None
      -}
      TcRnUnsupportedCallConv :: Either (ForeignExport GhcRn) (ForeignImport GhcRn)
                              -> UnsupportedCallConvention
                              -> TcRnMessage

      {-| TcRnIllegalForeignType is an error for when a type appears in a foreign
         function signature that is not compatible with the FFI.

         Example(s): None

        Test cases: ffi/should_fail/T3066
                    ffi/should_fail/ccfail004
                    ffi/should_fail/T10461
                    ffi/should_fail/T7506
                    ffi/should_fail/T5664
                    safeHaskell/ghci/p6
                    safeHaskell/safeLanguage/SafeLang08
                    ffi/should_fail/T16702
                    linear/should_fail/LinearFFI
                    ffi/should_fail/T7243
      -}
      TcRnIllegalForeignType :: !(Maybe ArgOrResult) -> !IllegalForeignTypeReason -> TcRnMessage

      {-| TcRnInvalidCIdentifier indicates a C identifier that is not valid.

         Example(s):
         foreign import prim safe "not valid" cmm_test2 :: Int# -> Int#

        Test cases: th/T10638
      -}
      TcRnInvalidCIdentifier :: !CLabelString -> TcRnMessage

      {-| TcRnExpectedValueId is an error occurring when something that is not a
          value identifier is used where one is expected.

         Example(s): none

        Test cases: none
      -}
      TcRnExpectedValueId :: !TcTyThing -> TcRnMessage

      {-| TcRnRecSelectorEscapedTyVar is an error indicating that a record field selector
         containing an existential type variable is used as a function rather than in
         a pattern match.

         Example(s):
         data Rec = forall a. Rec { field :: a }
         field (Rec True)

        Test cases: patsyn/should_fail/records-exquant
                    typecheck/should_fail/T3176
      -}
      TcRnRecSelectorEscapedTyVar :: !OccName -> TcRnMessage

      {-| TcRnPatSynNotBidirectional is an error for when a non-bidirectional pattern
         synonym is used as a constructor.

         Example(s):
         pattern Five :: Int
         pattern Five <- 5
         five = Five

        Test cases: patsyn/should_fail/records-no-uni-update
                    patsyn/should_fail/records-no-uni-update2
      -}
      TcRnPatSynNotBidirectional :: !Name -> TcRnMessage

      {-| TcRnIllegalDerivingItem is an error for when something other than a type class
         appears in a deriving statement.

         Example(s):
         data X = X deriving Int

        Test cases: deriving/should_fail/T5922
      -}
      TcRnIllegalDerivingItem :: !(LHsSigType GhcRn) -> TcRnMessage

      {-| TcRnUnexpectedAnnotation indicates the erroroneous use of an annotation such
         as strictness, laziness, or unpacking.

         Example(s):
         data T = T { t :: Maybe {-# UNPACK #-} Int }
         data C = C { f :: !IntMap Int }

        Test cases: parser/should_fail/unpack_inside_type
                    typecheck/should_fail/T7210
                    rename/should_fail/T22478b
      -}
      TcRnUnexpectedAnnotation :: !(HsType GhcRn) -> !HsSrcBang -> TcRnMessage

      {-| TcRnIllegalRecordSyntax is an error indicating an illegal use of record syntax.

         Example(s):
         data T = T Int { field :: Int }

        Test cases: rename/should_fail/T7943
                    rename/should_fail/T9077
                    rename/should_fail/T22478b
      -}
      TcRnIllegalRecordSyntax :: Either (HsType GhcPs) (HsType GhcRn) -> TcRnMessage

      {-| TcRnInvalidVisibleKindArgument is an error for a kind application on a
         target type that cannot accept it.

         Example(s):
         bad :: Int @Type
         bad = 1
         type Foo :: forall a {b}. a -> b -> b
         type Foo x y = y
         type Bar = Foo @Bool @Int True 42

        Test cases: indexed-types/should_fail/T16356_Fail3
                    typecheck/should_fail/ExplicitSpecificity7
                    typecheck/should_fail/T12045b
                    typecheck/should_fail/T12045c
                    typecheck/should_fail/T15592a
                    typecheck/should_fail/T15816
      -}
      TcRnInvalidVisibleKindArgument
        :: !(LHsType GhcRn) -- ^ The visible kind argument
        -> !Type -- ^ Target of the kind application
        -> TcRnMessage

      {-| TcRnTooManyBinders is an error for a type constructor that is declared with
         more arguments then its kind specifies.

         Example(s):
         type T :: Type -> (Type -> Type) -> Type
         data T a (b :: Type -> Type) x1 (x2 :: Type -> Type)

        Test cases: saks/should_fail/saks_fail008
      -}
      TcRnTooManyBinders :: !Kind -> ![LHsTyVarBndr (HsBndrVis GhcRn) GhcRn] -> TcRnMessage

      {-| TcRnDifferentNamesForTyVar is an error that indicates different names being
         used for the same type variable.

         Example(s):
         data SameKind :: k -> k -> *
         data Q (a :: k1) (b :: k2) c = MkQ (SameKind a b)

        Test cases: polykinds/T11203
                    polykinds/T11821a
                    saks/should_fail/T20916
                    typecheck/should_fail/T17566b
                    typecheck/should_fail/T17566c
      -}
      TcRnDifferentNamesForTyVar :: !Name -> !Name -> TcRnMessage

      {-| TcRnDisconnectedTyVar is an error for a data declaration that has a kind signature,
          where the implicitly-bound type type variables can't be matched up unambiguously
          with the ones from the signature. See Note [Disconnected type variables] in
          GHC.Tc.Gen.HsType.

          Test cases: T24083
      -}
      TcRnDisconnectedTyVar :: !Name -> TcRnMessage

      {-| TcRnInvalidReturnKind is an error for a data declaration that has a kind signature
         with an invalid result kind.

         Example(s):
         data family Foo :: Constraint

        Test cases: typecheck/should_fail/T14048b
                    typecheck/should_fail/UnliftedNewtypesConstraintFamily
                    typecheck/should_fail/T12729
                    typecheck/should_fail/T15883
                    typecheck/should_fail/T16829a
                    typecheck/should_fail/T16829b
                    typecheck/should_fail/UnliftedNewtypesNotEnabled
                    typecheck/should_fail/tcfail079
      -}
      TcRnInvalidReturnKind
        :: !DataSort -- ^ classification of thing being returned
        -> !AllowedDataResKind -- ^ allowed kind
        -> !Kind -- ^ the return kind
        -> !(Maybe SuggestUnliftedTypes) -- ^ suggested extension
        -> TcRnMessage

      {-| TcRnUnexpectedKindVar is an error that occurs when the user
          tries to use kind variables without -XPolyKinds.

          Example:
            f :: forall k a. Proxy (a :: k)

          Test cases: polykinds/BadKindVar
                      polykinds/T14710
                      saks/should_fail/T16722
      -}
      TcRnUnexpectedKindVar :: RdrName -> TcRnMessage

      {-| TcRnIllegalKind is used for a various illegal kinds errors including

          Example:
            type T :: forall k. Type -- without emabled -XPolyKinds

          Test cases: polykinds/T16762b
      -}
      TcRnIllegalKind
        :: HsTypeOrSigType GhcPs
                -- ^ The illegal kind
        -> Bool -- ^ Whether enabling -XPolyKinds should be suggested
        -> TcRnMessage

      {-| TcRnClassKindNotConstraint is an error for a type class that has a kind that
         is not equivalent to Constraint.

         Example(s):
         type C :: Type -> Type
         class C a

        Test cases: saks/should_fail/T16826
      -}
      TcRnClassKindNotConstraint :: !Kind -> TcRnMessage

      {-| TcRnUnpromotableThing is an error that occurs when the user attempts to
         use the promoted version of something which is not promotable.

         Example(s):
         data T :: T -> *
         data X a where
           MkX :: Show a => a -> X a
         foo :: Proxy ('MkX 'True)
         foo = Proxy

        Test cases: dependent/should_fail/PromotedClass
                    dependent/should_fail/T14845_fail1
                    dependent/should_fail/T14845_fail2
                    dependent/should_fail/T15215
                    dependent/should_fail/T13780c
                    dependent/should_fail/T15245
                    polykinds/T5716
                    polykinds/T5716a
                    polykinds/T6129
                    polykinds/T7433
                    patsyn/should_fail/T11265
                    patsyn/should_fail/T9161-1
                    patsyn/should_fail/T9161-2
                    dependent/should_fail/SelfDep
                    polykinds/PolyKinds06
                    polykinds/PolyKinds07
                    polykinds/T13625
                    polykinds/T15116
                    polykinds/T15116a
                    saks/should_fail/T16727a
                    saks/should_fail/T16727b
                    rename/should_fail/T12686
                    rename/should_fail/T16635a
                    rename/should_fail/T16635b
                    rename/should_fail/T16635c
      -}
      TcRnUnpromotableThing :: !Name -> !PromotionErr -> TcRnMessage

      {- | TcRnIllegalTermLevelUse is an error that occurs when the user attempts to
           use a type-level entity at the term-level.

           Examples:
              f x = Int                 -- illegal use of a type constructor
              g (Proxy :: Proxy a) = a  -- illegal use of a type variable

           Note that the namespace cannot be used to determine if a name refers to a
           type-level entity:

              {-# LANGUAGE RequiredTypeArguments #-}
              bad :: forall (a :: k) -> k
              bad t = t

          The name `t` is assigned the `varName` namespace but stands for a type
          variable that cannot be used at the term level.

          Test cases: T18740a, T18740b, T23739_fail_ret, T23739_fail_case
      -}
      TcRnIllegalTermLevelUse :: !Name -> !TermLevelUseErr -> TcRnMessage

      {-| TcRnMatchesHaveDiffNumArgs is an error occurring when something has matches
         that have different numbers of arguments

         Example(s):
         foo x = True
         foo x y = False

        Test cases: rename/should_fail/rnfail045
                    typecheck/should_fail/T20768_fail
      -}
      TcRnMatchesHaveDiffNumArgs
        :: !HsMatchContextRn   -- ^ Pattern match specifics
        -> !MatchArgBadMatches
        -> TcRnMessage

      {-| TcRnUnexpectedPatSigType is an error occurring when there is
          a type signature in a pattern without -XScopedTypeVariables extension

          Examples:
            f (a :: Bool) = ...

          Test case: rename/should_fail/T11663
      -}
      TcRnUnexpectedPatSigType :: HsPatSigType GhcPs -> TcRnMessage

      {-| TcRnIllegalKindSignature is an error occurring when there is
          a kind signature without -XKindSignatures extension

          Examples:
            data Foo (a :: Nat) = ....

          Test case: parser/should_fail/readFail036
      -}
      TcRnIllegalKindSignature :: HsType GhcPs -> TcRnMessage

      {-| TcRnDataKindsError is an error occurring when there is
          an illegal type or kind, probably required -XDataKinds
          and is used without the enabled extension.

          This error can occur in both the renamer and the typechecker. The field
          of type @'Either' ('HsType' 'GhcPs') 'Type'@ reflects this: this field
          will contain a 'Left' value if the error occurred in the renamer, and this
          field will contain a 'Right' value if the error occurred in the
          typechecker.

          Examples:

            type Foo = [Nat, Char]

            type Bar = [Int, String]

          Test cases: linear/should_fail/T18888
                      parser/should_fail/readFail001
                      polykinds/T7151
                      polykinds/T7433
                      rename/should_fail/T13568
                      rename/should_fail/T22478e
                      th/TH_Promoted1Tuple
                      typecheck/should_compile/tcfail094
                      typecheck/should_compile/T22141a
                      typecheck/should_compile/T22141b
                      typecheck/should_compile/T22141c
                      typecheck/should_compile/T22141d
                      typecheck/should_compile/T22141e
                      typecheck/should_compile/T22141f
                      typecheck/should_compile/T22141g
                      typecheck/should_fail/T20873c
                      typecheck/should_fail/T20873d
      -}
      TcRnDataKindsError :: TypeOrKind -> Either (HsType GhcPs) Type -> TcRnMessage

      {-| TcRnCannotBindScopedTyVarInPatSig is an error stating that scoped type
         variables cannot be used in pattern bindings.

         Example(s):
         let (x :: a) = 5

         Test cases: typecheck/should_compile/tc141
      -}
      TcRnCannotBindScopedTyVarInPatSig :: !(NE.NonEmpty (Name, TcTyVar)) -> TcRnMessage

      {-| TcRnCannotBindTyVarsInPatBind is an error for when type
         variables are introduced in a pattern binding

         Example(s):
         Just @a x = Just True

        Test cases: typecheck/should_fail/TyAppPat_PatternBinding
                    typecheck/should_fail/TyAppPat_PatternBindingExistential
      -}
      TcRnCannotBindTyVarsInPatBind :: !(NE.NonEmpty (Name, TcTyVar)) -> TcRnMessage

      {-| TcRnTooManyTyArgsInConPattern is an error occurring when a constructor pattern
         has more than the expected number of type arguments

         Example(s):
         f (Just @Int @Bool x) = x

        Test cases: typecheck/should_fail/TyAppPat_TooMany
                    typecheck/should_fail/T20443b
      -}
      TcRnTooManyTyArgsInConPattern
        :: !ConLike
        -> !Int -- ^ Expected number of args
        -> !Int -- ^ Actual number of args
        -> TcRnMessage

      {-| TcRnMultipleInlinePragmas is a warning signifying that multiple inline pragmas
         reference the same definition.

         Example(s):
         {-# INLINE foo #-}
         {-# INLINE foo #-}
         foo :: Bool -> Bool
         foo = id

        Test cases: none
      -}
      TcRnMultipleInlinePragmas
        :: !Id -- ^ Target of the pragmas
        -> !(LocatedA InlinePragma) -- ^ The first pragma
        -> !(NE.NonEmpty (LocatedA InlinePragma)) -- ^ Other pragmas
        -> TcRnMessage

      {-| TcRnUnexpectedPragmas is a warning that occurs when unexpected pragmas appear
         in the source.

         Example(s):

        Test cases: none
      -}
      TcRnUnexpectedPragmas :: !Id -> !(NE.NonEmpty (LSig GhcRn)) -> TcRnMessage

      {-| TcRnNonOverloadedSpecialisePragma is a warning for a specialise pragma being
         placed on a definition that is not overloaded.

         Example(s):
         {-# SPECIALISE foo :: Bool -> Bool #-}
         foo :: Bool -> Bool
         foo = id

        Test cases: simplCore/should_compile/T8537
                    typecheck/should_compile/T10504
      -}
      TcRnNonOverloadedSpecialisePragma :: !(LIdP GhcRn) -> TcRnMessage

      {-| TcRnSpecialiseNotVisible is a warning that occurs when the subject of a
         SPECIALISE pragma has a definition that is not visible from the current module.

         Example(s): none

        Test cases: none
      -}
      TcRnSpecialiseNotVisible :: !Name -> TcRnMessage

      {-| TcRnPragmaWarning is a warning that can happen when usage of something
         is warned or deprecated by pragma.

        Test cases:
          DeprU
          T5281
          T5867
          rn050
          rn066 (here is a warning, not deprecation)
          T3303
          ExportWarnings1
          ExportWarnings2
          ExportWarnings3
          ExportWarnings4
          ExportWarnings5
          ExportWarnings6
          InstanceWarnings
      -}
      TcRnPragmaWarning :: {
        TcRnMessage -> PragmaWarningInfo
    pragma_warning_info :: PragmaWarningInfo,
        TcRnMessage -> WarningTxt GhcRn
    pragma_warning_msg :: WarningTxt GhcRn
      } -> TcRnMessage

      {-| TcRnDifferentExportWarnings is an error that occurs when the
         warning messages for exports of a name differ between several export items.

         Test case:
          DifferentExportWarnings
      -}
      TcRnDifferentExportWarnings :: !Name -- ^ The name with different export warnings
                                  -> NE.NonEmpty SrcSpan -- ^ The locations of export list items that differ
                                                --   from the one at which the error is reported
                                  -> TcRnMessage

      {-| TcRnIncompleteExportWarnings is a warning (controlled by -Wincomplete-export-warnings) that
         occurs when some of the exports of a name do not have an export warning and some do

         Test case:
          ExportWarnings6
      -}
      TcRnIncompleteExportWarnings :: !Name -- ^ The name that is exported
                                   -> NE.NonEmpty SrcSpan -- ^ The locations of export list items that are
                                                 --   missing the export warning
                                   -> TcRnMessage

      {-| TcRnIllegalHsigDefaultMethods is an error that occurs when a binding for
         a class default method is provided in a Backpack signature file.

        Test case:
          bkpfail40
      -}
      TcRnIllegalHsigDefaultMethods :: !Name -- ^ 'Name' of the class
                                    -> NE.NonEmpty (LHsBind GhcRn) -- ^ default methods
                                    -> TcRnMessage

      {-| TcRnHsigFixityMismatch is an error indicating that the fixity decl in a
        Backpack signature file differs from the one in the source file for the same
        operator.

        Test cases:
          bkpfail37, bkpfail38
      -}
      TcRnHsigFixityMismatch :: !TyThing -- ^ The operator whose fixity is defined
                             -> !Fixity -- ^ the fixity used in the source file
                             -> !Fixity -- ^ the fixity used in the signature
                             -> TcRnMessage

      {-| TcRnHsigShapeMismatch is a group of errors related to mismatches between
        backpack signatures.
      -}
      TcRnHsigShapeMismatch :: !HsigShapeMismatchReason
                             -> TcRnMessage

      {-| TcRnHsigMissingModuleExport is an error indicating that a module doesn't
        export a name exported by its signature.

        Test cases:
          bkpfail01, bkpfail05, bkpfail09, bkpfail16, bkpfail35, bkpcabal06
      -}
      TcRnHsigMissingModuleExport :: !OccName -- ^ The missing name
                                  -> !UnitState -- ^ The module's unit state
                                  -> !Module -- ^ The implementation module
                                  -> TcRnMessage

      {-| TcRnBadGenericMethod
         This test ensures that if you provide a "more specific" type signatures
         for the default method, you must also provide a binding.

         Example:
         {-# LANGUAGE DefaultSignatures #-}

         class C a where
           meth :: a
           default meth :: Num a => a
           meth = 0

        Test case:
          typecheck/should_fail/MissingDefaultMethodBinding.hs
      -}
      TcRnBadGenericMethod :: !Name   -- ^ 'Name' of the class
                           -> !Name   -- ^ Problematic method
                           -> TcRnMessage

      {-| TcRnWarningMinimalDefIncomplete is a warning that one must
          specify which methods must be implemented by all instances.

         Example:
           class Cheater a where  -- WARNING LINE
           cheater :: a
           {-# MINIMAL #-} -- warning!

         Test case:
           warnings/minimal/WarnMinimal.hs:
      -}
      TcRnWarningMinimalDefIncomplete :: ClassMinimalDef -> TcRnMessage

      {-| TcRnIllegalQuasiQuotes is an error that occurs when a quasi-quote
          is used without the QuasiQuotes extension.

          Example:

            foo = [myQuoter|x y z|]

          Test cases: none; the parser fails to parse this if QuasiQuotes is off.
      -}
      TcRnIllegalQuasiQuotes :: TcRnMessage

      {-| TcRnTHError is a family of errors involving Template Haskell.
          See 'THError'.
      -}
      TcRnTHError :: THError -> TcRnMessage

      {-| TcRnDefaultMethodForPragmaLacksBinding is an error that occurs when
          a default method pragma is missing an accompanying binding.

        Test cases:
          typecheck/should_fail/T5084.hs
          typecheck/should_fail/T2354.hs
      -}
      TcRnDefaultMethodForPragmaLacksBinding
                :: Id             -- ^ method
                -> Sig GhcRn      -- ^ the pragma
                -> TcRnMessage
      {-| TcRnIgnoreSpecialisePragmaOnDefMethod is a warning that occurs when
          a specialise pragma is put on a default method.

        Test cases: none
      -}
      TcRnIgnoreSpecialisePragmaOnDefMethod
                :: !Name
                -> TcRnMessage
      {-| TcRnBadMethodErr is an error that happens when one attempts to provide a method
          in a class instance, when the class doesn't have a method by that name.

         Test case:
           th/T12387
      -}
      TcRnBadMethodErr
        :: { TcRnMessage -> Name
    badMethodErrClassName  :: !Name
           , TcRnMessage -> Name
    badMethodErrMethodName :: !Name
           } -> TcRnMessage

      {-| TcRnIllegalNewtype is an error that occurs when a newtype:

          * Does not have exactly one field, or
          * is non-linear, or
          * is a GADT, or
          * has a context in its constructor's type, or
          * has existential type variables in its constructor's type, or
          * has strictness annotations.

        Test cases:
          gadt/T14719
          indexed-types/should_fail/T14033
          indexed-types/should_fail/T2334A
          linear/should_fail/LinearGADTNewtype
          parser/should_fail/readFail008
          polykinds/T11459
          typecheck/should_fail/T15523
          typecheck/should_fail/T15796
          typecheck/should_fail/T17955
          typecheck/should_fail/T18891a
          typecheck/should_fail/T21447
          typecheck/should_fail/tcfail156
      -}
      TcRnIllegalNewtype
                :: DataCon
                -> Bool -- ^ True if linear types enabled
                -> IllegalNewtypeReason
                -> TcRnMessage

      {-| TcRnIllegalTypeData is an error that occurs when a @type data@
          declaration occurs without the TypeOperators extension.

          See Note [Type data declarations]

         Test case:
           type-data/should_fail/TDNoPragma
      -}
      TcRnIllegalTypeData :: TcRnMessage

      {-| TcRnTypeDataForbids is an error that occurs when a @type data@
          declaration contains @data@ declaration features that are
          forbidden in a @type data@ declaration.

          See Note [Type data declarations]

         Test cases:
           type-data/should_fail/TDDeriving
           type-data/should_fail/TDRecordsGADT
           type-data/should_fail/TDRecordsH98
           type-data/should_fail/TDStrictnessGADT
           type-data/should_fail/TDStrictnessH98
      -}
      TcRnTypeDataForbids :: !TypeDataForbids -> TcRnMessage

      {-| TcRnUnsatisfiedMinimalDef is a warning that occurs when a class instance
           is missing methods that are required by the minimal definition.

           Example:
              class C a where
                foo :: a -> a
              instance C ()        -- | foo needs to be defined here

           Test cases:
             typecheck/prog001/typecheck.prog001
             typecheck/should_compile/tc126
             typecheck/should_compile/T7903
             typecheck/should_compile/tc116
             typecheck/should_compile/tc175
             typecheck/should_compile/HasKey
             typecheck/should_compile/tc125
             typecheck/should_compile/tc078
             typecheck/should_compile/tc161
             typecheck/should_fail/T5051
             typecheck/should_compile/T21583
             backpack/should_compile/bkp47
             backpack/should_fail/bkpfail25
             parser/should_compile/T2245
             parser/should_compile/read014
             indexed-types/should_compile/Class3
             indexed-types/should_compile/Simple2
             indexed-types/should_fail/T7862
             deriving/should_compile/deriving-1935
             deriving/should_compile/T9968a
             deriving/should_compile/drv003
             deriving/should_compile/T4966
             deriving/should_compile/T14094
             perf/compiler/T15304
             warnings/minimal/WarnMinimal
             simplCore/should_compile/simpl020
             deSugar/should_compile/T14546d
             ghci/scripts/T5820
             ghci/scripts/ghci019
      -}
      TcRnUnsatisfiedMinimalDef :: ClassMinimalDef -> TcRnMessage

      {-| 'TcRnMisplacedInstSig' is an error that happens when a method in
           a class instance is given a type signature, but the user has not
           enabled the @InstanceSigs@ extension.

           Test case: module/mod45
      -}
      TcRnMisplacedInstSig :: Name -> (LHsSigType GhcRn) -> TcRnMessage
      {-| TcRnNoRebindableSyntaxRecordDot is an error triggered by an overloaded record update
          without RebindableSyntax enabled.

          Example(s):

         Test cases: parser/should_fail/RecordDotSyntaxFail5
      -}
      TcRnNoRebindableSyntaxRecordDot :: TcRnMessage

      {-| TcRnNoFieldPunsRecordDot is an error triggered by the use of record field puns
          in an overloaded record update without enabling NamedFieldPuns.

          Example(s):
          print $ a{ foo.bar.baz.quux }

         Test cases: parser/should_fail/RecordDotSyntaxFail12
      -}
      TcRnNoFieldPunsRecordDot :: TcRnMessage

      {-| TcRnIllegalStaticExpression is an error thrown when user creates a static
          pointer via TemplateHaskell without enabling the StaticPointers extension.

          Example(s):

         Test cases: th/T14204
      -}
      TcRnIllegalStaticExpression :: HsExpr GhcPs -> TcRnMessage

      {-| TcRnListComprehensionDuplicateBinding is an error triggered by duplicate
          let-bindings in a list comprehension.

          Example(s):
          [ () | let a = 13 | let a = 17 ]

         Test cases: typecheck/should_fail/tcfail092
      -}
      TcRnListComprehensionDuplicateBinding :: Name -> TcRnMessage

      {-| TcRnEmptyStmtsGroup is an error triggered by an empty list of statements
          in a statement block. For more information, see 'EmptyStatementGroupErrReason'

          Example(s):

            [() | then ()]

            do

            proc () -> do

         Test cases: rename/should_fail/RnEmptyStatementGroup1
      -}
      TcRnEmptyStmtsGroup:: EmptyStatementGroupErrReason -> TcRnMessage

      {-| TcRnLastStmtNotExpr is an error caused by the last statement
          in a statement block not being an expression.

          Example(s):

            do x <- pure ()

            do let x = 5

         Test cases: rename/should_fail/T6060
                     parser/should_fail/T3811g
                     parser/should_fail/readFail028
      -}
      TcRnLastStmtNotExpr
        :: HsStmtContextRn
        -> UnexpectedStatement
        -> TcRnMessage

      {-| TcRnUnexpectedStatementInContext is an error when a statement appears
          in an unexpected context (e.g. an arrow statement appears in a list comprehension).

          Example(s):

         Test cases: parser/should_fail/readFail042
                     parser/should_fail/readFail038
                     parser/should_fail/readFail043
      -}
      TcRnUnexpectedStatementInContext
        :: HsStmtContextRn
        -> UnexpectedStatement
        -> Maybe LangExt.Extension
        -> TcRnMessage

      {-| TcRnIllegalTupleSection is an error triggered by usage of a tuple section
          without enabling the TupleSections extension.

          Example(s):
            (5,)

         Test cases: rename/should_fail/rnfail056
      -}
      TcRnIllegalTupleSection :: TcRnMessage

      {-| TcRnIllegalImplicitParameterBindings is an error triggered by binding
          an implicit parameter in an mdo block.

          Example(s):
          mdo { let { ?x = 5 }; () }

         Test cases: rename/should_fail/RnImplicitBindInMdoNotation
      -}
      TcRnIllegalImplicitParameterBindings
        :: Either (HsLocalBindsLR GhcPs GhcPs) (HsLocalBindsLR GhcRn GhcPs)
        -> TcRnMessage

      {-| TcRnSectionWithoutParentheses is an error triggered by attempting to
          use an operator section without parentheses.

          Example(s):
          (`head` x, ())

         Test cases: rename/should_fail/T2490
                     rename/should_fail/T5657
      -}
      TcRnSectionWithoutParentheses :: HsExpr GhcPs -> TcRnMessage

      {-| TcRnBindingOfExistingName is an error triggered by an attempt to rebind
         built-in syntax, punned list or tuple syntax, or a name quoted via Template Haskell.

         Examples:

           data []
           data (->)
           $(pure [ValD (VarP 'succ) (NormalB (ConE 'True)) []])

         Test cases: rename/should_fail/T14907b
                     rename/should_fail/T22839
                     rename/should_fail/rnfail042
                     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 for EmptyCaseWithoutFlag:

           {-# LANGUAGE NoEmptyCase #-}
           f :: Void -> a
           f = \case {}    -- extension not enabled

         Example for EmptyCaseDisallowedCtxt:

           f = \cases {}   -- multi-case requires n>0 alternatives

         Example for EmptyCaseForall:

           f :: forall (xs :: Type) -> ()
           f = \case {}    -- can't match on a type argument

         Test cases: rename/should_fail/RnEmptyCaseFail
                     typecheck/should_fail/T25004
      -}
      TcRnEmptyCase :: !HsMatchContextRn
                    -> !BadEmptyCaseReason
                    -> 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

      {-| 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

      {-| 'TcRnIllegalInvisTyVarBndr' is an error that occurs
          when invisible type variable binders in type declarations
          are used without enabling the @TypeAbstractions@ extension.

          Example:
            {-# LANGUAGE NoTypeAbstractions #-}         -- extension disabled
            data T @k (a :: k) @(j :: Type) (b :: j)
                   ^^          ^^^^^^^^^^^^

          Test case: T22560_fail_ext
      -}
      TcRnIllegalInvisTyVarBndr
        :: !(LHsTyVarBndr (HsBndrVis GhcRn) GhcRn)
        -> TcRnMessage

      {-| 'TcRnInvalidInvisTyVarBndr' is an error that occurs
          when an invisible type variable binder has no corresponding
          @forall k.@ quantifier in the standalone kind signature.

          Example:
            type P :: forall a -> Type
            data P @a = MkP

          Test cases: T22560_fail_a T22560_fail_b
      -}
      TcRnInvalidInvisTyVarBndr
        :: !Name
        -> !(LHsTyVarBndr (HsBndrVis GhcRn) GhcRn)
        -> TcRnMessage

      {-| 'TcRnInvisBndrWithoutSig' is an error triggered by attempting to use
          an invisible type variable binder in a type declaration without a
          standalone kind signature or a complete user-supplied kind.

          Example:
            data T @k (a :: k)     -- No CUSK, no SAKS

          Test case: T22560_fail_d
      -}
      TcRnInvisBndrWithoutSig
        :: !Name
        -> !(LHsTyVarBndr (HsBndrVis GhcRn) GhcRn)
        -> TcRnMessage

      {-| TcRnDeprecatedInvisTyArgInConPat is a warning that triggers on type applications
          in constructor patterns when the user has not enabled '-XTypeAbstractions'
          but instead has enabled both '-XScopedTypeVariables' and '-XTypeApplications'.

          This warning is a deprecation mechanism that is scheduled until GHC 9.12.
      -}
      TcRnDeprecatedInvisTyArgInConPat
        :: TcRnMessage

      {-| TcRnUnexpectedStandaloneDerivingDecl is an error thrown when a user uses
          standalone deriving without enabling the StandaloneDeriving extension.

          Example:

            deriving instance Eq Foo

          Test cases: rename/should_fail/RnUnexpectedStandaloneDeriving
      -}
      TcRnUnexpectedStandaloneDerivingDecl :: TcRnMessage

      {-| TcRnUnusedVariableInRuleDecl is an error triggered by forall'd variable in
          rewrite rule that does not appear on left-hand side

          Example:

            {-# RULES "rule" forall a. id = id #-}

          Test cases: rename/should_fail/ExplicitForAllRules2
      -}
      TcRnUnusedVariableInRuleDecl :: FastString -> Name -> TcRnMessage

      {-| TcRnUnexpectedStandaloneKindSig is an error thrown when a user uses standalone
          kind signature without enabling the StandaloneKindSignatures extension.

          Example:

            type D :: Type
            data D = D

          Test cases: saks/should_fail/saks_fail001
      -}
      TcRnUnexpectedStandaloneKindSig :: TcRnMessage

      {-| TcRnIllegalRuleLhs is an error triggered by malformed left-hand side
          of rewrite rule

          Examples:

            {-# RULES "test" forall x. f x = x #-}

            {-# RULES "test" forall x. case x of = x #-}

          Test cases: rename/should_fail/T15659
      -}
      TcRnIllegalRuleLhs
        :: RuleLhsErrReason
        -> FastString -- Rule name
        -> LHsExpr GhcRn -- Full expression
        -> HsExpr GhcRn -- Bad expression
        -> TcRnMessage

      {-| TcRnDuplicateRoleAnnot is an error triggered by two or more role
          annotations for one type

          Example:

            data D a
            type role D phantom
            type role D phantom

          Test cases: roles/should_fail/Roles8
      -}
      TcRnDuplicateRoleAnnot :: NE.NonEmpty (LRoleAnnotDecl GhcPs) -> TcRnMessage

      {-| TcRnDuplicateKindSig is an error triggered by two or more standalone
          kind signatures for one type

          Example:

            type D :: Type
            type D :: Type
            data D

          Test cases: saks/should_fail/saks_fail002
      -}
      TcRnDuplicateKindSig :: NE.NonEmpty (LStandaloneKindSig GhcPs) -> TcRnMessage

      {-| TcRnIllegalDerivStrategy  is an error thrown when a user uses deriving
          strategy without enabling the DerivingStrategies extension or uses deriving
          via without enabling the DerivingVia extension.

          Examples:

            data T = T deriving stock Eq

            data T = T deriving via Eq T

          Test cases: deriving/should_fail/deriving-via-fail3
                      deriving/should_fail/T10598_fail4
      -}
      TcRnIllegalDerivStrategy :: DerivStrategy GhcPs -> TcRnMessage

      {-| TcRnIllegalMultipleDerivClauses is an error thrown when a user uses two or more
          deriving clauses without enabling the DerivingStrategies extension.

          Example:

            data T = T
              deriving Eq
              deriving Ord

          Test cases: deriving/should_fail/T10598_fail5
      -}
      TcRnIllegalMultipleDerivClauses :: TcRnMessage

      {-| TcRnNoDerivStratSpecified is a warning implied by -Wmissing-deriving-strategies
          and triggered by deriving clause without specified deriving strategy.

          Example:

            data T = T
              deriving Eq

          Test cases: rename/should_compile/T15798a
                      rename/should_compile/T15798b
                      rename/should_compile/T15798c
      -}
      TcRnNoDerivStratSpecified
        :: Bool -- True if DerivingStrategies is enabled
        -> TcRnMessage

      {-| TcRnStupidThetaInGadt is an error triggered by data contexts in GADT-style
          data declaration

          Example:

            data (Eq a) => D a where
              MkD :: D Int

          Test cases: rename/should_fail/RnStupidThetaInGadt
      -}
      TcRnStupidThetaInGadt :: HsDocContext -> TcRnMessage

      {-| TcRnShadowedTyVarNameInFamResult is an error triggered by type variable in
          type family result that shadows type variable from left hand side

          Example:

            type family F a b c = b

          Test cases: ghci/scripts/T6018ghcirnfail
                      rename/should_fail/T6018rnfail
      -}
      TcRnShadowedTyVarNameInFamResult :: IdP GhcPs -> TcRnMessage

      {-| TcRnIncorrectTyVarOnRhsOfInjCond is an error caused by a situation where the
          left-hand side of an injectivity condition of a type family is not a variable
          referring to the type family result.
          See Note [Renaming injectivity annotation] for more details.

          Example:

            type family F a = r | a -> a

          Test cases: ghci/scripts/T6018ghcirnfail
                      rename/should_fail/T6018rnfail
      -}
      TcRnIncorrectTyVarOnLhsOfInjCond
        :: IdP GhcRn -- Expected
        -> LIdP GhcPs -- Actual
        -> TcRnMessage

      {-| TcRnUnknownTyVarsOnRhsOfInjCond is an error triggered by out-of-scope type
          variables on the right-hand side of a of an injectivity condition of a type family

          Example:

            type family F a = res | res -> b

          Test cases: ghci/scripts/T6018ghcirnfail
                      rename/should_fail/T6018rnfail
      -}
      TcRnUnknownTyVarsOnRhsOfInjCond :: [Name] -> TcRnMessage

      {-| TcRnLookupInstance groups several errors emitted when looking up class instances.

        Test cases:
          none
      -}
      TcRnLookupInstance
        :: !Class
        -> ![Type]
        -> !LookupInstanceErrReason
        -> TcRnMessage

      {-| TcRnBadlyStaged is an error that occurs when a TH binding is used in an
        invalid stage.

        Test cases:
          T17820d
      -}
      TcRnBadlyStaged
        :: !StageCheckReason -- ^ The binding being spliced.
        -> !Int -- ^ The binding stage.
        -> !Int -- ^ The stage at which the binding is used.
        -> TcRnMessage

      {-| TcRnStageRestriction is an error that occurs when a top level splice refers to
        a local name.

        Test cases:
          T17820, T21547, T5795, qq00[1-4], annfail0{3,4,6,9}
      -}
      TcRnStageRestriction
        :: !StageCheckReason -- ^ The binding being spliced.
        -> TcRnMessage

      {-| TcRnBadlyStagedWarn is a warning that occurs when a TH type binding is
        used in an invalid stage.

        Controlled by flags:
           - Wbadly-staged-type

        Test cases:
          T23829_timely T23829_tardy T23829_hasty
      -}
      TcRnBadlyStagedType
        :: !Name  -- ^ The type binding being spliced.
        -> !Int -- ^ The binding stage.
        -> !Int -- ^ The stage at which the binding is used.
        -> TcRnMessage

      {-| TcRnTyThingUsedWrong is an error that occurs when a thing is used where another
        thing was expected.

        Test cases:
          none
      -}
      TcRnTyThingUsedWrong
        :: !WrongThingSort -- ^ Expected thing.
        -> !TcTyThing -- ^ Thing used wrongly.
        -> !Name -- ^ Name of the thing used wrongly.
        -> TcRnMessage

      {-| TcRnCannotDefaultKindVar is an error that occurs when attempting to use
        unconstrained kind variables whose type isn't @Type@, without -XPolyKinds.

        Test cases:
          T11334b
      -}
      TcRnCannotDefaultKindVar
        :: !TyVar -- ^ The unconstrained variable.
        -> !Kind -- ^ Kind of the variable.
        -> TcRnMessage

      {-| TcRnUninferrableTyVar is an error that occurs when metavariables
        in a type could not be defaulted.

        Test cases:
          T17301, T17562, T17567, T17567StupidTheta, T15474, T21479
      -}
      TcRnUninferrableTyVar
        :: ![TyCoVar] -- ^ The variables that could not be defaulted.
        -> !UninferrableTyVarCtx -- ^ Description of the surrounding context.
        -> TcRnMessage

      {-| TcRnSkolemEscape is an error that occurs when type variables from an
        outer scope is used in a context where they should be locally scoped.

        Test cases:
          T15076, T15076b, T14880-2, T15825, T14880, T15807, T16946, T14350,
          T14040A, T15795, T15795a, T14552
      -}
      TcRnSkolemEscape
        :: ![TcTyVar] -- ^ The variables that would escape.
        -> !TcTyVar -- ^ The variable that is being quantified.
        -> !Type -- ^ The type in which they occur.
        -> TcRnMessage

      {-| TcRnPatSynEscapedCoercion is an error indicating that a coercion escaped from
        a pattern synonym into a type.
        See Note [Coercions that escape] in GHC.Tc.TyCl.PatSyn

        Test cases:
          T14507
      -}
      TcRnPatSynEscapedCoercion :: !Id -- ^ The pattern-bound variable
                                -> !(NE.NonEmpty CoVar) -- ^ The escaped coercions
                                -> TcRnMessage

      {-| TcRnPatSynExistentialInResult is an error indicating that the result type
        of a pattern synonym mentions an existential type variable.

        Test cases:
          PatSynExistential
      -}
      TcRnPatSynExistentialInResult :: !Name -- ^ The name of the pattern synonym
                                    -> !TcSigmaType -- ^ The result type
                                    -> ![TyVar] -- ^ The escaped existential variables
                                    -> TcRnMessage

      {-| TcRnPatSynArityMismatch is an error indicating that the number of arguments in a
        pattern synonym's equation differs from the number of parameters in its
        signature.

        Test cases:
          PatSynArity
      -}
      TcRnPatSynArityMismatch :: !Name -- ^ The name of the pattern synonym
                              -> !Arity -- ^ The number of equation arguments
                              -> !Arity -- ^ The difference
                              -> TcRnMessage

      {-| TcRnPatSynInvalidRhs is an error group indicating that the pattern on the
        right hand side of a pattern synonym is invalid.

        Test cases:
          unidir, T14112
      -}
      TcRnPatSynInvalidRhs :: !Name -- ^ The name of the pattern synonym
                           -> !(LPat GhcRn) -- ^ The pattern
                           -> ![LIdP GhcRn] -- ^ The LHS args
                           -> !PatSynInvalidRhsReason -- ^ The number of equation arguments
                           -> TcRnMessage

      {-| TcRnZonkerMessage is collection of errors that occur when zonking,
          i.e. filling in metavariables with their final values.

          See 'ZonkerMessage'
      -}
      TcRnZonkerMessage :: ZonkerMessage -> TcRnMessage

      {-| TcRnTyFamDepsDisabled is an error indicating that a type family injectivity
        annotation was used without enabling the extension TypeFamilyDependencies.

        Test cases:
          T11381
      -}
      TcRnTyFamDepsDisabled :: TcRnMessage

      {-| TcRnAbstractClosedTyFamDecl is an error indicating that an abstract closed
        type family was declared in a regular source file, while it is only allowed
        in hs-boot files.

        Test cases:
          ClosedFam4
      -}
      TcRnAbstractClosedTyFamDecl :: TcRnMessage

      {-| TcRnPartialFieldSelector is a warning indicating that a record selector
        was not defined for all constructors of a data type.

        Test cases:
          DRFPartialFields, T7169
      -}
      TcRnPartialFieldSelector :: !FieldLabel -- ^ The selector
                               -> TcRnMessage

      {-| TcRnHasFieldResolvedIncomplete is a warning triggered when a HasField constraint
          is resolved for a record field for which a `getField @"field"` application
          might not be successful. Currently, this means that the warning is triggered when
          the parent data type of that record field does not have that field in all
          its constructors.

          Example(s):
          data T = T1 | T2 {x :: Bool}
          f :: HasField t "x" Bool => t -> Bool
          f = getField @"x"
          g :: T -> Bool
          g = f

         Test cases:
           TcIncompleteRecSel
      -}
      TcRnHasFieldResolvedIncomplete :: !Name -> TcRnMessage

      {-| TcRnBadFieldAnnotation is an error/warning group indicating that a
        strictness/unpack related data type field annotation is invalid.
      -}
      TcRnBadFieldAnnotation :: !Int -- ^ The index of the field
                             -> !DataCon -- ^ The constructor in which the field is defined
                             -> !BadFieldAnnotationReason -- ^ The error specifics
                             -> TcRnMessage

      {-| TcRnSuperclassCycle is an error indicating that a class has a superclass
        cycle.

        Test cases:
          mod40, tcfail027, tcfail213, tcfail216, tcfail217, T9415, T9739
      -}
      TcRnSuperclassCycle :: !SuperclassCycle -- ^ The details of the cycle
                          -> TcRnMessage

      {-| TcRnDefaultSigMismatch is an error indicating that a default method
        signature doesn't match the regular method signature.

        Test cases:
          T7437, T12918a, T12918b, T12151
      -}
      TcRnDefaultSigMismatch :: !Id -- ^ The name of the method
                             -> !Type -- ^ The type of the default signature
                             -> TcRnMessage

      {-| TcRnTyFamsDisabled is an error indicating that a type family or instance
        was declared while the extension TypeFamilies was disabled.

        Test cases:
          TyFamsDisabled
      -}
      TcRnTyFamsDisabled :: !TyFamsDisabledReason -- ^ The name of the family or instance
                         -> TcRnMessage

      {-| TcRnBadTyConTelescope is an error caused by an ill-scoped 'TyCon' kind,
         due to type variables being out of dependency order.

         Example:

          class C a (b :: Proxy a) (c :: Proxy b) where
            type T c a

         Test cases:
           BadTelescope{∅,3,4}
           T14066{f,g}
           T14887
           T15591{b,c}
           T15743{c,d}
           T15764
           T23252

      -}
      TcRnBadTyConTelescope :: !TyCon -> TcRnMessage

      {-| TcRnTyFamResultDisabled is an error indicating that a result variable
        was used on a type family while the extension TypeFamilyDependencies was
        disabled.

        Test cases:
          T13571, T13571a
      -}
      TcRnTyFamResultDisabled :: !Name -- ^ The name of the type family
                              -> !(LHsTyVarBndr () GhcRn) -- ^ Name of the result variable
                              -> TcRnMessage

      {-| TcRnRoleValidationFailed is an error indicating that a variable was
        assigned an invalid role by the inference algorithm.
        This is only performed with -dcore-lint.
      -}
      TcRnRoleValidationFailed :: !Role -- ^ The validated role
                               -> !RoleValidationFailedReason -- ^ The failure reason
                               -> TcRnMessage

      {-| TcRnCommonFieldResultTypeMismatch is an error indicating that a sum type
        declares the same field name in multiple constructors, but the constructors'
        result types differ.

        Test cases:
          CommonFieldResultTypeMismatch
      -}
      TcRnCommonFieldResultTypeMismatch :: !DataCon -- ^ First constructor
                                        -> !DataCon -- ^ Second constructor
                                        -> !FieldLabelString -- ^ Field name
                                        -> TcRnMessage

      {-| TcRnCommonFieldTypeMismatch is an error indicating that a sum type
        declares the same field name in multiple constructors, but their types
        differ.

        Test cases:
          CommonFieldTypeMismatch
      -}
      TcRnCommonFieldTypeMismatch :: !DataCon -- ^ First constructor
                                  -> !DataCon -- ^ Second constructor
                                  -> !FieldLabelString -- ^ Field name
                                  -> TcRnMessage

      {-| TcRnClassExtensionDisabled is an error indicating that a class
        was declared with an extension feature while the extension was disabled.
      -}
      TcRnClassExtensionDisabled :: !Class -- ^ The class
                                 -> !DisabledClassExtension -- ^ The extension
                                 -> TcRnMessage

      {-| TcRnDataConParentTypeMismatch is an error indicating that a data
        constructor was declared with a type that doesn't match its type
        constructor (i.e. a GADT result type and its data name).

        Test cases:
          T7175, T13300, T14719, T18357, T18357b, gadt11, tcfail155, tcfail176
      -}
      TcRnDataConParentTypeMismatch :: !DataCon -- ^ The data constructor
                                    -> !Type -- ^ The parent type
                                    -> TcRnMessage

      {-| TcRnGADTsDisabled is an error indicating that a GADT was declared
        while the extension GADTs was disabled.

        Test cases:
          ghci057, T9293
      -}
      TcRnGADTsDisabled :: !Name -- ^ The name of the GADT
                        -> TcRnMessage

      {-| TcRnExistentialQuantificationDisabled is an error indicating that
        a data constructor was declared with existential features while the
        extension ExistentialQuantification was disabled.

        Test cases:
          ghci057, T9293, gadtSyntaxFail001, gadtSyntaxFail002, gadtSyntaxFail003,
          prog006, rnfail053, T12083a
      -}
      TcRnExistentialQuantificationDisabled :: !DataCon -- ^ The constructor
                                            -> TcRnMessage

      {-| TcRnGADTDataContext is an error indicating that a GADT was declared with a
        data type context.
        This error is emitted in the tc, but it is also caught in the renamer.
      -}
      TcRnGADTDataContext :: !Name -- ^ The data type name
                          -> TcRnMessage

      {-| TcRnMultipleConForNewtype is an error indicating that a newtype was
        declared with multiple constructors.
        This error is caught by the parser.
      -}
      TcRnMultipleConForNewtype :: !Name -- ^ The newtype name
                                -> !Int -- ^ The number of constructors
                                -> TcRnMessage

      {-| TcRnKindSignaturesDisabled is an error indicating that a kind signature
        was used in a data type declaration while the extension KindSignatures was
        disabled.

        Test cases:
          T20873c, readFail036
      -}
      TcRnKindSignaturesDisabled :: !(Either (HsType GhcPs) (Name, HsType GhcRn))
                                    -- ^ The data type name
                                 -> TcRnMessage

      {-| TcRnEmptyDataDeclsDisabled is an error indicating that a data type
        was declared with no constructors while the extension EmptyDataDecls was
        disabled.

        Test cases:
          readFail035
      -}
      TcRnEmptyDataDeclsDisabled :: !Name -- ^ The data type name
                                 -> TcRnMessage

      {-| TcRnRoleMismatch is an error indicating that the role specified
        in an annotation differs from its inferred role.

        Test cases:
          T7253, Roles11
      -}
      TcRnRoleMismatch :: !Name -- ^ The type variable
                       -> !Role -- ^ The annotated role
                       -> !Role -- ^ The inferred role
                       -> TcRnMessage

      {-| TcRnRoleCountMismatch is an error indicating that the number of
        roles in an annotation doesn't match the number of type parameters.

        Test cases:
          Roles6
      -}
      TcRnRoleCountMismatch :: !Int -- ^ The number of type variables
                            -> !(LRoleAnnotDecl GhcRn) -- ^ The role annotation
                            -> TcRnMessage

      {-| TcRnIllegalRoleAnnotation is an error indicating that a role
        annotation was attached to a decl that doesn't allow it.

        Test cases:
          Roles5
      -}
      TcRnIllegalRoleAnnotation :: !(RoleAnnotDecl GhcRn) -- ^ The role annotation
                                -> TcRnMessage

      {-| TcRnRoleAnnotationsDisabled is an error indicating that a role
        annotation was declared while the extension RoleAnnotations was disabled.

        Test cases:
          Roles5, TH_Roles1
      -}
      TcRnRoleAnnotationsDisabled :: !TyCon -- ^ The annotated type
                                  -> TcRnMessage

      {-| TcRnIncoherentRoles is an error indicating that a role
        annotation for a class parameter was declared as not nominal.

        Test cases:
          T8773
      -}
      TcRnIncoherentRoles :: !TyCon -- ^ The class tycon
                          -> TcRnMessage
      {-| TcRnPrecedenceParsingError is an error caused by attempting to
          use operators with the same precedence in one infix expression.

          Example:
            eq :: (a ~ b ~ c) :~: ()

          Test cases: module/mod61
                      parser/should_fail/readFail016
                      rename/should_fail/rnfail017
                      rename/should_fail/T9077
                      typecheck/should_fail/T18252a
      -}
      TcRnPrecedenceParsingError
        :: (OpName, Fixity) -- ^ first operator's name and fixity
        -> (OpName, Fixity) -- ^ second operator's name and fixity
        -> TcRnMessage

      {-| TcRnPrecedenceParsingError is an error caused by attempting to
          use an operator with higher precedence than the operand.

          Example:
            k = (-3 **)
              where
                    (**) = const
                    infixl 7 **

          Test cases: overloadedrecflds/should_fail/T13132_duplicaterecflds
                      parser/should_fail/readFail023
                      rename/should_fail/rnfail019
                      th/TH_unresolvedInfix2
      -}
      TcRnSectionPrecedenceError
        :: (OpName, Fixity) -- ^ first operator's name and fixity
        -> (OpName, Fixity) -- ^ argument operator
        -> HsExpr GhcPs -- ^ Section
        -> TcRnMessage

      {-| TcRnTypeSynonymCycle is an error indicating that a cycle between type
        synonyms has occurred.

        Test cases:
          mod27, ghc-e-fail2, bkpfail29
      -}
      TcRnTypeSynonymCycle :: !TySynCycleTyCons -- ^ The tycons involved in the cycle
                           -> TcRnMessage

      {-| TcRnSelfImport is an error indicating that a module contains an
        import of itself.

        Test cases:
          T9032
      -}
      TcRnSelfImport :: !ModuleName -- ^ The module
                     -> TcRnMessage

      {-| TcRnNoExplicitImportList is a warning indicating that an import
          statement did not include an explicit import list.

        Test cases:
          T1789, T4489
      -}
      TcRnNoExplicitImportList :: !ModuleName -- ^ The imported module
                               -> TcRnMessage

      {-| TcRnSafeImportsDisabled is an error indicating that an import was
        declared using the @safe@ keyword while SafeHaskell wasn't active.

        Test cases:
          Mixed01
      -}
      TcRnSafeImportsDisabled :: !ModuleName -- ^ The imported module
                               -> TcRnMessage

      {-| TcRnDeprecatedModule is a warning indicating that an imported module
        is annotated with a warning or deprecation pragma.

        Test cases:
          DeprU
      -}
      TcRnDeprecatedModule :: !ModuleName -- ^ The imported module
                           -> !(WarningTxt GhcRn) -- ^ The pragma data
                           -> TcRnMessage

      {-| TcRnCompatUnqualifiedImport is a warning indicating that a special
        module (right now only Data.List) was imported unqualified without
        import list, for compatibility reasons.

        Test cases:
          T17244A
      -}
      TcRnCompatUnqualifiedImport :: !(ImportDecl GhcPs) -- ^ The import
                                  -> TcRnMessage

      {-| TcRnRedundantSourceImport is a warning indicating that a {-# SOURCE #-}
        import was used when there is no import cycle.

        Test cases:
          none
      -}
      TcRnRedundantSourceImport :: !ModuleName -- ^ The imported module
                                -> TcRnMessage

      {-| TcRnImportLookup is a group of errors about bad imported names.
      -}
      TcRnImportLookup :: !ImportLookupReason -- ^ Details about the error
                       -> TcRnMessage

      {-| TcRnUnusedImport is a group of errors about unused imports.
      -}
      TcRnUnusedImport :: !(ImportDecl GhcRn) -- ^ The import
                       -> !UnusedImportReason -- ^ Details about the error
                       -> TcRnMessage

      {-| TcRnDuplicateDecls is an error indicating that the same name was used for
        multiple declarations.

        Test cases:
          FieldSelectors, overloadedrecfldsfail03, T17965, NFSDuplicate, T9975a,
          TDMultiple01, mod19, mod38, mod21, mod66, mod20, TDPunning, mod18, mod22,
          TDMultiple02, T4127a, ghci048, T8932, rnfail015, rnfail010, rnfail011,
          rnfail013, rnfail002, rnfail003, rn_dup, rnfail009, T7164, rnfail043,
          TH_dupdecl, rnfail012
      -}
      TcRnDuplicateDecls :: !OccName -- ^ The name of the declarations
                         -> !(NE.NonEmpty Name) -- ^ The individual declarations
                         -> TcRnMessage

      {-| TcRnPackageImportsDisabled is an error indicating that an import uses
        a package qualifier while the extension PackageImports was disabled.

        Test cases:
          PackageImportsDisabled
      -}
      TcRnPackageImportsDisabled :: TcRnMessage

      {-| TcRnIllegalDataCon is an error indicating that a data constructor was
        defined using a lowercase name, or a symbolic name in prefix position.
        Mostly caught by PsErrNotADataCon.

        Test cases:
          None
      -}
      TcRnIllegalDataCon :: !RdrName -- ^ The constructor name
                         -> TcRnMessage

      {-| TcRnNestedForallsContexts is an error indicating that multiple foralls or
        contexts are nested/curried where this is not supported,
        like @∀ x. ∀ y.@ instead of @∀ x y.@.

        Test cases:
          T12087, T14320, T16114, T16394, T16427, T18191, T18240a, T18240b, T18455, T5951
      -}
      TcRnNestedForallsContexts :: !NestedForallsContextsIn -> TcRnMessage

      {-| TcRnRedundantRecordWildcard is a warning indicating that a pattern uses
        a record wildcard even though all of the record's fields are bound explicitly.

        Test cases:
          T15957_Fail
      -}
      TcRnRedundantRecordWildcard :: TcRnMessage

      {-| TcRnUnusedRecordWildcard is a warning indicating that a pattern uses
        a record wildcard while none of the fields bound by it are used.

        Test cases:
          T15957_Fail
      -}
      TcRnUnusedRecordWildcard :: ![Name] -- ^ The names bound by the wildcard
                               -> TcRnMessage

      {-| TcRnUnusedName is a warning indicating that a defined or imported name
        is not used in the module.

        Test cases:
          ds053, mc10, overloadedrecfldsfail05, overloadedrecfldsfail06, prog018,
          read014, rn040, rn041, rn047, rn063, T13839, T13839a, T13919, T17171b,
          T17a, T17b, T17d, T17e, T18470, T1972, t22391, t22391j, T2497, T3371,
          T3449, T7145b, T7336, TH_recover_warns, unused_haddock, WarningGroups,
          werror
      -}
      TcRnUnusedName :: !OccName -- ^ The unused name
                     -> !UnusedNameProv -- ^ The provenance of the name
                     -> TcRnMessage

      {-| TcRnQualifiedBinder is an error indicating that a qualified name
        was used in binding position.

        Test cases:
          mod62, rnfail021, rnfail034, rnfail039, rnfail046
      -}
      TcRnQualifiedBinder :: !RdrName -- ^ The name used as a binder
                          -> TcRnMessage

      {-| TcRnTypeApplicationsDisabled is an error indicating that a type
        application was used while the extension TypeApplications was disabled.

        Test cases:
          T12411, T12446, T15527, T16133, T18251c
      -}
      TcRnTypeApplicationsDisabled :: !TypeApplication -- ^ what kind of type application is it?
                                   -> TcRnMessage

      {-| TcRnInvalidRecordField is an error indicating that a record field was
        used that doesn't exist in a constructor.

        Test cases:
          T13644, T13847, T17469, T8448, T8570, tcfail083, tcfail084
      -}
      TcRnInvalidRecordField :: !Name -- ^ The constructor name
                             -> !FieldLabelString -- ^ The name of the field
                             -> TcRnMessage

      {-| TcRnTupleTooLarge is an error indicating that the arity of a tuple
        exceeds mAX_TUPLE_SIZE.

        Test cases:
          T18723a, T18723b, T18723c, T6148a, T6148b, T6148c, T6148d
      -}
      TcRnTupleTooLarge :: !Int -- ^ The arity of the tuple
                        -> TcRnMessage

      {-| TcRnCTupleTooLarge is an error indicating that the arity of a constraint
        tuple exceeds mAX_CTUPLE_SIZE.

        Test cases:
          T10451
      -}
      TcRnCTupleTooLarge :: !Int -- ^ The arity of the constraint tuple
                         -> TcRnMessage

      {-| TcRnIllegalInferredTyVars is an error indicating that some type variables
        were quantified as inferred (like @∀ {a}.@) in a place where this is not
        allowed, like in an instance declaration.

        Test cases:
          ExplicitSpecificity5, ExplicitSpecificity6, ExplicitSpecificity8,
          ExplicitSpecificity9
      -}
      TcRnIllegalInferredTyVars :: !(NE.NonEmpty (HsTyVarBndr Specificity GhcPs))
                                  -- ^ The offending type variables
                               -> TcRnMessage

      {-| TcRnAmbiguousName is an error indicating that an unbound name
        might refer to multiple names in scope.

        Test cases:
          BootFldReexport, DRFUnused, duplicaterecfldsghci01, GHCiDRF, mod110,
          mod151, mod152, mod153, mod164, mod165, NoFieldSelectorsFail,
          overloadedrecfldsfail02, overloadedrecfldsfail04, overloadedrecfldsfail11,
          overloadedrecfldsfail12, overloadedrecfldsfail13,
          overloadedrecfldswasrunnowfail06, rnfail044, T11167_ambig,
          T11167_ambiguous_fixity, T13132_duplicaterecflds, T15487, T16745, T17420,
          T18999_NoDisambiguateRecordFields, T19397E1, T19397E2, T23010_fail,
          tcfail037
      -}
      TcRnAmbiguousName :: !GlobalRdrEnv
                        -> !RdrName -- ^ The name
                        -> !(NE.NonEmpty GlobalRdrElt) -- ^ The possible matches
                        -> TcRnMessage

      {-| TcRnBindingNameConflict is an error indicating that multiple local or
        top-level bindings have the same name.

        Test cases:
          dsrun006, mdofail002, mdofail003, mod23, mod24, qq006, rnfail001,
          rnfail004, SimpleFail6, T14114, T16110_Fail1, tcfail038, TH_spliceD1,
          T22478b, TyAppPat_NonlinearMultiAppPat, TyAppPat_NonlinearMultiPat,
          TyAppPat_NonlinearSinglePat,
      -}
      TcRnBindingNameConflict :: !RdrName -- ^ The conflicting name
                              -> !(NE.NonEmpty SrcSpan)
                                 -- ^ The locations of the duplicates
                              -> TcRnMessage

      {-| TcRnNonCanonicalDefinition is a warning indicating that an instance
        defines an implementation for a method that should not be defined in a way
        that deviates from its default implementation, for example because it has
        been scheduled to be absorbed into another method, like @pure@ making
        @return@ obsolete.

        Test cases:
          WCompatWarningsOn, WCompatWarningsOff, WCompatWarningsOnOff
      -}
      TcRnNonCanonicalDefinition :: !NonCanonicalDefinition -- ^ Specifics
                                 -> !(LHsSigType GhcRn) -- ^ The instance type
                                 -> TcRnMessage
      {-| TcRnImplicitImportOfPrelude is a warning, controlled by @Wimplicit-prelude@,
          that is triggered upon an implicit import of the @Prelude@ module.

          Example:

            {-# OPTIONS_GHC -fwarn-implicit-prelude #-}
            module M where {}

          Test case: rn055

      -}
      TcRnImplicitImportOfPrelude :: TcRnMessage

      {-| TcRnMissingMain is an error that occurs when a Main module does
          not define a main function (named @main@ by default, but overridable
          with the @main-is@ command line flag).

          Example:

            module Main where {}

          Test cases:
            T414, T7765, readFail021, rnfail007, T13839b, T17171a, T16453E1, tcfail030,
            T19397E3, T19397E4

      -}
      TcRnMissingMain
        :: !Bool -- ^ whether the module has an explicit export list
        -> !Module
        -> !OccName -- ^ the expected name of the main function
        -> TcRnMessage

      {-| TcRnGhciUnliftedBind is an error that occurs when a user attempts to
          bind an unlifted value in GHCi.

          Example (in GHCi):

            let a = (# 1#, 3# #)

          Test cases: T9140, T19035b
      -}
      TcRnGhciUnliftedBind :: !Id -> TcRnMessage

      {-| TcRnGhciMonadLookupFail is an error that occurs when the user sets
          the GHCi monad, using the GHC API 'setGHCiMonad' function, but GHC
          can't find which monad the user is referring to.

          Example:

            import GHC ( setGHCiMonad )

            ... setGHCiMonad "NoSuchThing"

          Test cases: none
      -}
      TcRnGhciMonadLookupFail
        :: String -- ^ the textual name of the monad requested by the user
        -> Maybe [GlobalRdrElt] -- ^ lookup result
        -> TcRnMessage

      {-| TcRnMissingRoleAnnotation is a warning that occurs when type declaration
         doesn't have a role annotatiosn

         Controlled by flags:
           - Wmissing-role-annotations

         Test cases:
           T22702

      -}
      TcRnMissingRoleAnnotation :: Name -> [Role] -> TcRnMessage
      {-| TcRnPatersonCondFailure is an error that occurs when an instance
          declaration fails to conform to the Paterson conditions. Which particular condition
          fails depends on the constructor of PatersonCondFailure
          See Note [Paterson conditions].

          Test cases:
            T15231, tcfail157, T15316, T19187a, fd-loop, tcfail108, tcfail154,
            T15172, tcfail214
      -}
      TcRnPatersonCondFailure
        :: PatersonCondFailure -- ^ the failed Paterson Condition
        -> PatersonCondFailureContext
        -> Type                -- ^ the LHS
        -> Type                -- ^ the RHS
        -> TcRnMessage

      {-| TcRnImplicitRhsQuantification is a warning that occurs when GHC implicitly
          quantifies over a type variable that occurs free on the RHS of the type declaration
          that is not mentioned on the LHS

          Example:

            type T = 'Nothing :: Maybe a

          Controlled by flags:
           - Wimplicit-rhs-quantification

          Test cases:
              T23510a
              T23510b
      -}
      TcRnImplicitRhsQuantification :: LocatedN RdrName -> TcRnMessage

      {-| TcRnIllformedTypePattern is an error raised when the pattern
          corresponding to a required type argument (visible forall)
          does not have a form that can be interpreted as a type pattern.

          Example:

            vfun :: forall (a :: k) -> ()
            vfun !x = ()
            --   ^^
            -- bang-patterns not allowed as type patterns

          Test cases:
              T22326_fail_bang_pat
      -}
      TcRnIllformedTypePattern :: !(Pat GhcRn) -> TcRnMessage

      {-| TcRnIllegalTypePattern is an error raised when a pattern constructed
          with the @type@ keyword occurs in a position that does not correspond
          to a required type argument (visible forall).

          Example:

            case x of
              (type _) -> True     -- the (type _) pattern is illegal here
              _        -> False

          Test cases:
            T22326_fail_ado
            T22326_fail_caseof
      -}
      TcRnIllegalTypePattern :: TcRnMessage

      {-| TcRnIllformedTypeArgument is an error raised when an argument
          that specifies a required type argument (instantiates a visible forall)
          does not have a form that can be interpreted as a type argument.

          Example:

            vfun :: forall (a :: k) -> ()
            x = vfun (\_ -> _)
            --       ^^^^^^^^^
            -- lambdas not allowed in type arguments

          Test cases:
            T22326_fail_lam_arg
      -}
      TcRnIllformedTypeArgument :: !(LHsExpr GhcRn) -> TcRnMessage

      {-| TcRnIllegalTypeExpr is an error raised when an expression constructed
          with the @type@ keyword occurs in a position that does not correspond
          to a required type argument (visible forall).

          Example:

            xtop = type Int                  -- not a function argument
            xarg = length (type Int)         -- `length` does not expect a required type argument

          Test cases:
            T22326_fail_app
            T22326_fail_top
      -}
      TcRnIllegalTypeExpr :: TcRnMessage

      {-| TcRnInvalidDefaultedTyVar is an error raised when a
          defaulting plugin proposes to default a type variable that is
          not an unfilled metavariable

          Test cases:
            T23832_invalid
      -}
      TcRnInvalidDefaultedTyVar
          :: ![Ct]                -- ^ The constraints passed to the plugin
          -> [(TcTyVar, Type)]    -- ^ The plugin-proposed type variable defaults
          -> NE.NonEmpty TcTyVar  -- ^ The invalid type variables of the proposal
          -> TcRnMessage

      {-| TcRnNamespacedWarningPragmaWithoutFlag is an error that occurs when
          a namespace specifier is used in {-# WARNING ... #-} or {-# DEPRECATED ... #-}
          pragmas without the -XExplicitNamespaces extension enabled

          Example:

            {-# LANGUAGE NoExplicitNamespaces #-}
            f = id
            {-# WARNING data f "some warning message" #-}

          Test cases:
            T24396c
      -}
      TcRnNamespacedWarningPragmaWithoutFlag :: WarnDecl GhcPs -> TcRnMessage

      {-| TcRnInvisPatWithNoForAll is an error raised when invisible type pattern
          is used without associated `forall` in types

          Examples:

            f :: Int
            f @t = 5

            g :: [a -> a]
            g = [\ @t x -> x :: t]

          Test cases: T17694c T17594d
      -}
      TcRnInvisPatWithNoForAll :: HsTyPat GhcRn -> TcRnMessage

      {-| TcRnIllegalInvisibleTypePattern is an error raised when invisible type pattern
          is used without the TypeAbstractions extension enabled

          Example:

            {-# LANGUAGE NoTypeAbstractions #-}
            id :: a -> a
            id @t x = x

          Test cases: T17694b
      -}
      TcRnIllegalInvisibleTypePattern :: HsTyPat GhcPs -> TcRnMessage

      {-| TcRnNamespacedFixitySigWithoutFlag is an error that occurs when
          a namespace specifier is used in fixity signatures
          without the -XExplicitNamespaces extension enabled

          Example:

            {-# LANGUAGE NoExplicitNamespaces #-}
            f = const
            infixl 7 data `f`

          Test cases:
            T14032c
      -}
      TcRnNamespacedFixitySigWithoutFlag :: FixitySig GhcPs -> TcRnMessage

      {-| TcRnDefaultedExceptionContext is a warning that is triggered when the
          backward-compatibility logic solving for implicit ExceptionContext
          constraints fires.

          Test cases: DefaultExceptionContext
      -}
      TcRnDefaultedExceptionContext :: CtLoc -> TcRnMessage

      {-| TcRnOutOfArityTyVar is an error raised when the arity of a type synonym
          (as determined by the SAKS and the LHS) is insufficiently high to
          accommodate an implicit binding for a free variable that occurs in the
          outermost kind signature on the RHS of the said type synonym.

          Example:

            type SynBad :: forall k. k -> Type
            type SynBad = Proxy :: j -> Type

          Test cases:
            T24770a
      -}
      TcRnOutOfArityTyVar
        :: Name -- ^ Type synonym's name
        -> Name -- ^ Type variable's name
        -> TcRnMessage

      {- TcRnMisplacedInvisPat is an error raised when invisible @-pattern
         appears in invalid context (e.g. pattern in case of or in do-notation)
         or nested inside the pattern. Template Haskell seems to be the only
         source for this diagnostic.

         Examples:

            f (smth, $(invisP (varT (newName "blah")))) = ...

            g = do
              $(invisP (varT (newName "blah"))) <- aciton1
              ...

         Test cases:

      -}
      TcRnMisplacedInvisPat :: HsTyPat GhcPs -> TcRnMessage
      deriving (forall x. TcRnMessage -> Rep TcRnMessage x)
    -> (forall x. Rep TcRnMessage x -> TcRnMessage)
    -> Generic TcRnMessage
    forall x. Rep TcRnMessage x -> TcRnMessage
    forall x. TcRnMessage -> Rep TcRnMessage x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. TcRnMessage -> Rep TcRnMessage x
    from :: forall x. TcRnMessage -> Rep TcRnMessage x
    $cto :: forall x. Rep TcRnMessage x -> TcRnMessage
    to :: forall x. Rep TcRnMessage x -> TcRnMessage
    Generic

    ----

    data ZonkerMessage where
      {-| ZonkerCannotDefaultConcrete is an error occurring when a concrete
        type variable cannot be defaulted.

        Test cases:
          T23153
      -}
      ZonkerCannotDefaultConcrete
        :: !FixedRuntimeRepOrigin
        -> ZonkerMessage

      deriving (forall x. ZonkerMessage -> Rep ZonkerMessage x)
    -> (forall x. Rep ZonkerMessage x -> ZonkerMessage)
    -> Generic ZonkerMessage
    forall x. Rep ZonkerMessage x -> ZonkerMessage
    forall x. ZonkerMessage -> Rep ZonkerMessage x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. ZonkerMessage -> Rep ZonkerMessage x
    from :: forall x. ZonkerMessage -> Rep ZonkerMessage x
    $cto :: forall x. Rep ZonkerMessage x -> ZonkerMessage
    to :: forall x. Rep ZonkerMessage x -> ZonkerMessage
    Generic

    ----

    -- | Things forbidden in @type data@ declarations.
    -- See Note [Type data declarations]
    data TypeDataForbids
      = TypeDataForbidsDatatypeContexts
      | TypeDataForbidsLabelledFields
      | TypeDataForbidsStrictnessAnnotations
      | TypeDataForbidsDerivingClauses
      deriving (forall x. TypeDataForbids -> Rep TypeDataForbids x)
    -> (forall x. Rep TypeDataForbids x -> TypeDataForbids)
    -> Generic TypeDataForbids
    forall x. Rep TypeDataForbids x -> TypeDataForbids
    forall x. TypeDataForbids -> Rep TypeDataForbids x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. TypeDataForbids -> Rep TypeDataForbids x
    from :: forall x. TypeDataForbids -> Rep TypeDataForbids x
    $cto :: forall x. Rep TypeDataForbids x -> TypeDataForbids
    to :: forall x. Rep TypeDataForbids x -> TypeDataForbids
    Generic

    instance Outputable TypeDataForbids where
      ppr :: TypeDataForbids -> SDoc
    ppr TypeDataForbids
    TypeDataForbidsDatatypeContexts      = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "Data type contexts"
      ppr TypeDataForbids
    TypeDataForbidsLabelledFields        = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "Labelled fields"
      ppr TypeDataForbids
    TypeDataForbidsStrictnessAnnotations = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "Strictness flags"
      ppr TypeDataForbids
    TypeDataForbidsDerivingClauses       = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "Deriving clauses"

    -- | Specifies which back ends can handle a requested foreign import or export
    type ExpectedBackends = [Backend]

    -- | Specifies which calling convention is unsupported on the current platform
    data UnsupportedCallConvention
      = StdCallConvUnsupported
      | PrimCallConvUnsupported
      | JavaScriptCallConvUnsupported
      deriving UnsupportedCallConvention -> UnsupportedCallConvention -> Bool
    (UnsupportedCallConvention -> UnsupportedCallConvention -> Bool)
    -> (UnsupportedCallConvention -> UnsupportedCallConvention -> Bool)
    -> Eq UnsupportedCallConvention
    forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
    $c== :: UnsupportedCallConvention -> UnsupportedCallConvention -> Bool
    == :: UnsupportedCallConvention -> UnsupportedCallConvention -> Bool
    $c/= :: UnsupportedCallConvention -> UnsupportedCallConvention -> Bool
    /= :: UnsupportedCallConvention -> UnsupportedCallConvention -> Bool
    Eq

    -- | Whether the error pertains to a function argument or a result.
    data ArgOrResult
      = Arg | Result

    -- | Which parts of a record field are affected by a particular error or warning.
    data RecordFieldPart
      = RecordFieldDecl !Name
      | RecordFieldConstructor !Name
      | RecordFieldPattern !Name
      | RecordFieldUpdate

    -- | Why did we reject a record update?
    data BadRecordUpdateReason
       -- | No constructor has all of the required fields.
       = NoConstructorHasAllFields
           { BadRecordUpdateReason -> [FieldLabelString]
    conflictingFields :: [FieldLabelString] }

       -- | There are several possible parents which have all of the required fields,
       -- and we weren't able to disambiguate in any way.
       | MultiplePossibleParents
           (RecSelParent, RecSelParent, [RecSelParent])
             -- ^ The possible parents (at least 2)

       -- | We used type-directed disambiguation, but this resulted in
       -- an invalid parent (the type-directed parent is not among the
       -- parents we computed from the field labels alone).
       | InvalidTyConParent TyCon (NE.NonEmpty RecSelParent)

      deriving (forall x. BadRecordUpdateReason -> Rep BadRecordUpdateReason x)
    -> (forall x. Rep BadRecordUpdateReason x -> BadRecordUpdateReason)
    -> Generic BadRecordUpdateReason
    forall x. Rep BadRecordUpdateReason x -> BadRecordUpdateReason
    forall x. BadRecordUpdateReason -> Rep BadRecordUpdateReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. BadRecordUpdateReason -> Rep BadRecordUpdateReason x
    from :: forall x. BadRecordUpdateReason -> Rep BadRecordUpdateReason x
    $cto :: forall x. Rep BadRecordUpdateReason x -> BadRecordUpdateReason
    to :: forall x. Rep BadRecordUpdateReason x -> BadRecordUpdateReason
    Generic

    -- | Where a shadowed name comes from
    data ShadowedNameProvenance
      = ShadowedNameProvenanceLocal !SrcLoc
        -- ^ The shadowed name is local to the module
      | ShadowedNameProvenanceGlobal [GlobalRdrElt]
        -- ^ The shadowed name is global, typically imported from elsewhere.

    -- | In what context did we require a type to have a fixed runtime representation?
    --
    -- Used by 'GHC.Tc.Utils.TcMType.checkTypeHasFixedRuntimeRep' for throwing
    -- representation polymorphism errors when validity checking.
    --
    -- See Note [Representation polymorphism checking] in GHC.Tc.Utils.Concrete
    data FixedRuntimeRepProvenance
      -- | Data constructor fields must have a fixed runtime representation.
      --
      -- Tests: T11734, T18534.
      = FixedRuntimeRepDataConField

      -- | Pattern synonym signature arguments must have a fixed runtime representation.
      --
      -- Test: RepPolyPatSynArg.
      | FixedRuntimeRepPatSynSigArg

      -- | Pattern synonym signature scrutinee must have a fixed runtime representation.
      --
      -- Test: RepPolyPatSynRes.
      | FixedRuntimeRepPatSynSigRes

    pprFixedRuntimeRepProvenance :: FixedRuntimeRepProvenance -> SDoc
    pprFixedRuntimeRepProvenance :: FixedRuntimeRepProvenance -> SDoc
    pprFixedRuntimeRepProvenance FixedRuntimeRepProvenance
    FixedRuntimeRepDataConField = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "data constructor field"
    pprFixedRuntimeRepProvenance FixedRuntimeRepProvenance
    FixedRuntimeRepPatSynSigArg = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "pattern synonym argument"
    pprFixedRuntimeRepProvenance FixedRuntimeRepProvenance
    FixedRuntimeRepPatSynSigRes = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "pattern synonym scrutinee"

    -- | Why the particular illegal newtype error arose together with more
    -- information, if any.
    data IllegalNewtypeReason
      = DoesNotHaveSingleField !Int
      | IsNonLinear
      | IsGADT
      | HasConstructorContext
      | HasExistentialTyVar
      | HasStrictnessAnnotation
      deriving (forall x. IllegalNewtypeReason -> Rep IllegalNewtypeReason x)
    -> (forall x. Rep IllegalNewtypeReason x -> IllegalNewtypeReason)
    -> Generic IllegalNewtypeReason
    forall x. Rep IllegalNewtypeReason x -> IllegalNewtypeReason
    forall x. IllegalNewtypeReason -> Rep IllegalNewtypeReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. IllegalNewtypeReason -> Rep IllegalNewtypeReason x
    from :: forall x. IllegalNewtypeReason -> Rep IllegalNewtypeReason x
    $cto :: forall x. Rep IllegalNewtypeReason x -> IllegalNewtypeReason
    to :: forall x. Rep IllegalNewtypeReason x -> IllegalNewtypeReason
    Generic

    -- | Why the particular injectivity error arose together with more information,
    -- if any.
    data InjectivityErrReason
      = InjErrRhsBareTyVar [Type]
      | InjErrRhsCannotBeATypeFam
      | InjErrRhsOverlap
      | InjErrCannotInferFromRhs !TyVarSet !HasKinds !SuggestUndecidableInstances

    data HasKinds
      = YesHasKinds
      | NoHasKinds
      deriving (Int -> HasKinds -> ShowS
    [HasKinds] -> ShowS
    HasKinds -> String
    (Int -> HasKinds -> ShowS)
    -> (HasKinds -> String) -> ([HasKinds] -> ShowS) -> Show HasKinds
    forall a.
    (Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
    $cshowsPrec :: Int -> HasKinds -> ShowS
    showsPrec :: Int -> HasKinds -> ShowS
    $cshow :: HasKinds -> String
    show :: HasKinds -> String
    $cshowList :: [HasKinds] -> ShowS
    showList :: [HasKinds] -> ShowS
    Show, HasKinds -> HasKinds -> Bool
    (HasKinds -> HasKinds -> Bool)
    -> (HasKinds -> HasKinds -> Bool) -> Eq HasKinds
    forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
    $c== :: HasKinds -> HasKinds -> Bool
    == :: HasKinds -> HasKinds -> Bool
    $c/= :: HasKinds -> HasKinds -> Bool
    /= :: HasKinds -> HasKinds -> Bool
    Eq)

    hasKinds :: Bool -> HasKinds
    hasKinds :: Bool -> HasKinds
    hasKinds Bool
    True  = HasKinds
    YesHasKinds
    hasKinds Bool
    False = HasKinds
    NoHasKinds

    data SuggestUndecidableInstances
      = YesSuggestUndecidableInstaces
      | NoSuggestUndecidableInstaces
      deriving (Int -> SuggestUndecidableInstances -> ShowS
    [SuggestUndecidableInstances] -> ShowS
    SuggestUndecidableInstances -> String
    (Int -> SuggestUndecidableInstances -> ShowS)
    -> (SuggestUndecidableInstances -> String)
    -> ([SuggestUndecidableInstances] -> ShowS)
    -> Show SuggestUndecidableInstances
    forall a.
    (Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
    $cshowsPrec :: Int -> SuggestUndecidableInstances -> ShowS
    showsPrec :: Int -> SuggestUndecidableInstances -> ShowS
    $cshow :: SuggestUndecidableInstances -> String
    show :: SuggestUndecidableInstances -> String
    $cshowList :: [SuggestUndecidableInstances] -> ShowS
    showList :: [SuggestUndecidableInstances] -> ShowS
    Show, SuggestUndecidableInstances -> SuggestUndecidableInstances -> Bool
    (SuggestUndecidableInstances
     -> SuggestUndecidableInstances -> Bool)
    -> (SuggestUndecidableInstances
        -> SuggestUndecidableInstances -> Bool)
    -> Eq SuggestUndecidableInstances
    forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
    $c== :: SuggestUndecidableInstances -> SuggestUndecidableInstances -> Bool
    == :: SuggestUndecidableInstances -> SuggestUndecidableInstances -> Bool
    $c/= :: SuggestUndecidableInstances -> SuggestUndecidableInstances -> Bool
    /= :: SuggestUndecidableInstances -> SuggestUndecidableInstances -> Bool
    Eq)

    suggestUndecidableInstances :: Bool -> SuggestUndecidableInstances
    suggestUndecidableInstances :: Bool -> SuggestUndecidableInstances
    suggestUndecidableInstances Bool
    True  = SuggestUndecidableInstances
    YesSuggestUndecidableInstaces
    suggestUndecidableInstances Bool
    False = SuggestUndecidableInstances
    NoSuggestUndecidableInstaces

    data SuggestUnliftedTypes
      = SuggestUnliftedNewtypes
      | SuggestUnliftedDatatypes

    -- | A description of whether something is a
    --
    -- * @data@ or @newtype@ ('DataDeclSort')
    --
    -- * @data instance@ or @newtype instance@ ('DataInstanceSort')
    --
    -- * @data family@ ('DataFamilySort')
    --
    -- At present, this data type is only consumed by 'checkDataKindSig'.
    data DataSort
      = DataDeclSort     NewOrData
      | DataInstanceSort NewOrData
      | DataFamilySort

    ppDataSort :: DataSort -> SDoc
    ppDataSort :: DataSort -> SDoc
    ppDataSort DataSort
    data_sort = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text (String -> SDoc) -> String -> SDoc
    forall a b. (a -> b) -> a -> b
    $
      case DataSort
    data_sort of
        DataDeclSort     NewOrData
    DataType -> String
    "Data type"
        DataDeclSort     NewOrData
    NewType  -> String
    "Newtype"
        DataInstanceSort NewOrData
    DataType -> String
    "Data instance"
        DataInstanceSort NewOrData
    NewType  -> String
    "Newtype instance"
        DataSort
    DataFamilySort            -> String
    "Data family"

    -- | Helper type used in 'checkDataKindSig'.
    --
    -- Superficially similar to 'ContextKind', but it lacks 'AnyKind'
    -- and 'AnyBoxedKind', and instead of @'TheKind' liftedTypeKind@
    -- provides 'LiftedKind', which is much simpler to match on and
    -- handle in 'isAllowedDataResKind'.
    data AllowedDataResKind
      = AnyTYPEKind
      | AnyBoxedKind
      | LiftedKind

    -- | A data type to describe why a variable is not closed.
    -- See Note [Not-closed error messages] in GHC.Tc.Gen.Expr
    data NotClosedReason = NotLetBoundReason
                         | NotTypeClosed VarSet
                         | NotClosed Name NotClosedReason

    data SuggestPartialTypeSignatures
      = YesSuggestPartialTypeSignatures
      | NoSuggestPartialTypeSignatures
      deriving (Int -> SuggestPartialTypeSignatures -> ShowS
    [SuggestPartialTypeSignatures] -> ShowS
    SuggestPartialTypeSignatures -> String
    (Int -> SuggestPartialTypeSignatures -> ShowS)
    -> (SuggestPartialTypeSignatures -> String)
    -> ([SuggestPartialTypeSignatures] -> ShowS)
    -> Show SuggestPartialTypeSignatures
    forall a.
    (Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
    $cshowsPrec :: Int -> SuggestPartialTypeSignatures -> ShowS
    showsPrec :: Int -> SuggestPartialTypeSignatures -> ShowS
    $cshow :: SuggestPartialTypeSignatures -> String
    show :: SuggestPartialTypeSignatures -> String
    $cshowList :: [SuggestPartialTypeSignatures] -> ShowS
    showList :: [SuggestPartialTypeSignatures] -> ShowS
    Show, SuggestPartialTypeSignatures
    -> SuggestPartialTypeSignatures -> Bool
    (SuggestPartialTypeSignatures
     -> SuggestPartialTypeSignatures -> Bool)
    -> (SuggestPartialTypeSignatures
        -> SuggestPartialTypeSignatures -> Bool)
    -> Eq SuggestPartialTypeSignatures
    forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
    $c== :: SuggestPartialTypeSignatures
    -> SuggestPartialTypeSignatures -> Bool
    == :: SuggestPartialTypeSignatures
    -> SuggestPartialTypeSignatures -> Bool
    $c/= :: SuggestPartialTypeSignatures
    -> SuggestPartialTypeSignatures -> Bool
    /= :: SuggestPartialTypeSignatures
    -> SuggestPartialTypeSignatures -> Bool
    Eq)

    suggestPartialTypeSignatures :: Bool -> SuggestPartialTypeSignatures
    suggestPartialTypeSignatures :: Bool -> SuggestPartialTypeSignatures
    suggestPartialTypeSignatures Bool
    True  = SuggestPartialTypeSignatures
    YesSuggestPartialTypeSignatures
    suggestPartialTypeSignatures Bool
    False = SuggestPartialTypeSignatures
    NoSuggestPartialTypeSignatures

    data UsingGeneralizedNewtypeDeriving
      = YesGeneralizedNewtypeDeriving
      | NoGeneralizedNewtypeDeriving
      deriving UsingGeneralizedNewtypeDeriving
    -> UsingGeneralizedNewtypeDeriving -> Bool
    (UsingGeneralizedNewtypeDeriving
     -> UsingGeneralizedNewtypeDeriving -> Bool)
    -> (UsingGeneralizedNewtypeDeriving
        -> UsingGeneralizedNewtypeDeriving -> Bool)
    -> Eq UsingGeneralizedNewtypeDeriving
    forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
    $c== :: UsingGeneralizedNewtypeDeriving
    -> UsingGeneralizedNewtypeDeriving -> Bool
    == :: UsingGeneralizedNewtypeDeriving
    -> UsingGeneralizedNewtypeDeriving -> Bool
    $c/= :: UsingGeneralizedNewtypeDeriving
    -> UsingGeneralizedNewtypeDeriving -> Bool
    /= :: UsingGeneralizedNewtypeDeriving
    -> UsingGeneralizedNewtypeDeriving -> Bool
    Eq

    usingGeneralizedNewtypeDeriving :: Bool -> UsingGeneralizedNewtypeDeriving
    usingGeneralizedNewtypeDeriving :: Bool -> UsingGeneralizedNewtypeDeriving
    usingGeneralizedNewtypeDeriving Bool
    True  = UsingGeneralizedNewtypeDeriving
    YesGeneralizedNewtypeDeriving
    usingGeneralizedNewtypeDeriving Bool
    False = UsingGeneralizedNewtypeDeriving
    NoGeneralizedNewtypeDeriving

    data DeriveAnyClassEnabled
      = YesDeriveAnyClassEnabled
      | NoDeriveAnyClassEnabled
      deriving DeriveAnyClassEnabled -> DeriveAnyClassEnabled -> Bool
    (DeriveAnyClassEnabled -> DeriveAnyClassEnabled -> Bool)
    -> (DeriveAnyClassEnabled -> DeriveAnyClassEnabled -> Bool)
    -> Eq DeriveAnyClassEnabled
    forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
    $c== :: DeriveAnyClassEnabled -> DeriveAnyClassEnabled -> Bool
    == :: DeriveAnyClassEnabled -> DeriveAnyClassEnabled -> Bool
    $c/= :: DeriveAnyClassEnabled -> DeriveAnyClassEnabled -> Bool
    /= :: DeriveAnyClassEnabled -> DeriveAnyClassEnabled -> Bool
    Eq

    deriveAnyClassEnabled :: Bool -> DeriveAnyClassEnabled
    deriveAnyClassEnabled :: Bool -> DeriveAnyClassEnabled
    deriveAnyClassEnabled Bool
    True  = DeriveAnyClassEnabled
    YesDeriveAnyClassEnabled
    deriveAnyClassEnabled Bool
    False = DeriveAnyClassEnabled
    NoDeriveAnyClassEnabled

    -- | Why a particular typeclass instance couldn't be derived.
    data DeriveInstanceErrReason
      =
        -- | The typeclass instance is not well-kinded.
        DerivErrNotWellKinded !TyCon
                              -- ^ The type constructor that occurs in
                              -- the typeclass instance declaration.
                              !Kind
                              -- ^ The typeclass kind.
                              !Int
                              -- ^ The number of typeclass arguments that GHC
                              -- kept. See Note [tc_args and tycon arity] in
                              -- GHC.Tc.Deriv.
      -- | Generic instances can only be derived using the stock strategy
      -- in Safe Haskell.
      | DerivErrSafeHaskellGenericInst
      | DerivErrDerivingViaWrongKind !Kind !Type !Kind
      | DerivErrNoEtaReduce !Type
                            -- ^ The instance type
      -- | We cannot derive instances in boot files
      | DerivErrBootFileFound
      | DerivErrDataConsNotAllInScope !TyCon
      -- | We cannot use GND on non-newtype types
      | DerivErrGNDUsedOnData
      -- | We cannot derive instances of nullary classes
      | DerivErrNullaryClasses
      -- | Last arg must be newtype or data application
      | DerivErrLastArgMustBeApp
      | DerivErrNoFamilyInstance !TyCon [Type]
      | DerivErrNotStockDeriveable !DeriveAnyClassEnabled
      | DerivErrHasAssociatedDatatypes !HasAssociatedDataFamInsts
                                       !AssociatedTyLastVarInKind
                                       !AssociatedTyNotParamOverLastTyVar
      | DerivErrNewtypeNonDeriveableClass
      | DerivErrCannotEtaReduceEnough !Bool -- Is eta-reduction OK?
      | DerivErrOnlyAnyClassDeriveable !TyCon
                                       -- ^ Type constructor for which the instance
                                       -- is requested
                                       !DeriveAnyClassEnabled
                                       -- ^ Whether or not -XDeriveAnyClass is enabled
                                       -- already.
      -- | Stock deriving won't work, but perhaps DeriveAnyClass will.
      | DerivErrNotDeriveable !DeriveAnyClassEnabled
      -- | The given 'PredType' is not a class.
      | DerivErrNotAClass !PredType
      -- | The given (representation of the) 'TyCon' has no
      -- data constructors.
      | DerivErrNoConstructors !TyCon
      | DerivErrLangExtRequired !LangExt.Extension
      -- | GHC simply doesn't how to how derive the input 'Class' for the given
      -- 'Type'.
      | DerivErrDunnoHowToDeriveForType !Type
      -- | The given 'TyCon' must be an enumeration.
      -- See Note [Enumeration types] in GHC.Core.TyCon
      | DerivErrMustBeEnumType !TyCon
      -- | The given 'TyCon' must have /precisely/ one constructor.
      | DerivErrMustHaveExactlyOneConstructor !TyCon
      -- | The given data type must have some parameters.
      | DerivErrMustHaveSomeParameters !TyCon
      -- | The given data type must not have a class context.
      | DerivErrMustNotHaveClassContext !TyCon !ThetaType
      -- | We couldn't derive an instance for a particular data constructor
      -- for a variety of reasons.
      | DerivErrBadConstructor !(Maybe HasWildcard) [DeriveInstanceBadConstructor]
      -- | We couldn't derive a 'Generic' instance for the given type for a
      -- variety of reasons
      | DerivErrGenerics [DeriveGenericsErrReason]
      -- | We couldn't derive an instance either because the type was not an
      -- enum type or because it did have more than one constructor.
      | DerivErrEnumOrProduct !DeriveInstanceErrReason !DeriveInstanceErrReason
      deriving (forall x.
     DeriveInstanceErrReason -> Rep DeriveInstanceErrReason x)
    -> (forall x.
        Rep DeriveInstanceErrReason x -> DeriveInstanceErrReason)
    -> Generic DeriveInstanceErrReason
    forall x. Rep DeriveInstanceErrReason x -> DeriveInstanceErrReason
    forall x. DeriveInstanceErrReason -> Rep DeriveInstanceErrReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. DeriveInstanceErrReason -> Rep DeriveInstanceErrReason x
    from :: forall x. DeriveInstanceErrReason -> Rep DeriveInstanceErrReason x
    $cto :: forall x. Rep DeriveInstanceErrReason x -> DeriveInstanceErrReason
    to :: forall x. Rep DeriveInstanceErrReason x -> DeriveInstanceErrReason
    Generic

    data DeriveInstanceBadConstructor
      =
      -- | The given 'DataCon' must be truly polymorphic in the
      -- last argument of the data type.
        DerivErrBadConExistential !DataCon
      -- | The given 'DataCon' must not use the type variable in a function argument"
      | DerivErrBadConCovariant !DataCon
      -- | The given 'DataCon' must not contain function types
      | DerivErrBadConFunTypes !DataCon
      -- | The given 'DataCon' must use the type variable only
      -- as the last argument of a data type
      | DerivErrBadConWrongArg !DataCon
      -- | The given 'DataCon' is a GADT so we cannot directly
      -- derive an istance for it.
      | DerivErrBadConIsGADT !DataCon
      -- | The given 'DataCon' has existentials type vars in its type.
      | DerivErrBadConHasExistentials !DataCon
      -- | The given 'DataCon' has constraints in its type.
      | DerivErrBadConHasConstraints !DataCon
      -- | The given 'DataCon' has a higher-rank type.
      | DerivErrBadConHasHigherRankType !DataCon

    data DeriveGenericsErrReason
      = -- | The type must not have some datatype context.
        DerivErrGenericsMustNotHaveDatatypeContext !TyCon
        -- | The data constructor must not have exotic unlifted
        -- or polymorphic arguments.
      | DerivErrGenericsMustNotHaveExoticArgs !DataCon
        -- | The data constructor must be a vanilla constructor.
      | DerivErrGenericsMustBeVanillaDataCon  !DataCon
        -- | The type must have some type parameters.
        -- check (d) from Note [Requirements for deriving Generic and Rep]
        -- in GHC.Tc.Deriv.Generics.
      | DerivErrGenericsMustHaveSomeTypeParams !TyCon
        -- | The data constructor must not have existential arguments.
      | DerivErrGenericsMustNotHaveExistentials !DataCon
        -- | The derivation applies a type to an argument involving
        -- the last parameter but the applied type is not of kind * -> *.
      | DerivErrGenericsWrongArgKind !DataCon

    data HasWildcard
      = YesHasWildcard
      | NoHasWildcard
      deriving HasWildcard -> HasWildcard -> Bool
    (HasWildcard -> HasWildcard -> Bool)
    -> (HasWildcard -> HasWildcard -> Bool) -> Eq HasWildcard
    forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
    $c== :: HasWildcard -> HasWildcard -> Bool
    == :: HasWildcard -> HasWildcard -> Bool
    $c/= :: HasWildcard -> HasWildcard -> Bool
    /= :: HasWildcard -> HasWildcard -> Bool
    Eq

    hasWildcard :: Bool -> HasWildcard
    hasWildcard :: Bool -> HasWildcard
    hasWildcard Bool
    True  = HasWildcard
    YesHasWildcard
    hasWildcard Bool
    False = HasWildcard
    NoHasWildcard

    -- | A context in which we don't allow anonymous wildcards.
    data BadAnonWildcardContext
      = WildcardNotLastInConstraint
      | ExtraConstraintWildcardNotAllowed
          SoleExtraConstraintWildcardAllowed
      | WildcardsNotAllowedAtAll

    -- | Whether a sole extra-constraint wildcard is allowed,
    -- e.g. @_ => ..@ as opposed to @( .., _ ) => ..@.
    data SoleExtraConstraintWildcardAllowed
      = SoleExtraConstraintWildcardNotAllowed
      | SoleExtraConstraintWildcardAllowed

    -- | Why is a class instance head invalid?
    data IllegalInstanceHeadReason
      -- | An instance for an abstract class from an hs-boot or Backpack
      -- hsig file.
      --
      --  Example:
      --
      --    -- A.hs-boot
      --    module A where
      --    class C a
      --
      --    -- B.hs
      --    module B where
      --    import {-# SOURCE #-} A
      --    instance C Int where
      --
      --    -- A.hs
      --    module A where
      --    import B
      --    class C a where
      --      f :: a
      --
      -- Test cases: typecheck/should_fail/T13068
      = InstHeadAbstractClass !Class
      -- | An instance whose head is not a class.
      --
      -- Examples(s):
      --
      --   instance c
      --
      --   instance 42
      --
      --   instance !Show D
      --
      --   type C1 a = (Show (a -> Bool))
      --   instance C1 Int where
      --
      -- Test cases: typecheck/rename/T5513
      --             typecheck/rename/T16385
      --             parser/should_fail/T3811c
      --             rename/should_fail/T18240a
      --             polykinds/T13267
      --             deriving/should_fail/T23522
      | InstHeadNonClass
        !(Maybe TyCon) -- ^ the 'TyCon' at the head of the instance head,
                       -- or 'Nothing' if the instance head is not even headed
                       -- by a 'TyCon'

      -- | Instance head was headed by a type synonym.
      --
      -- Example:
      --    type MyInt = Int
      --    class C a where {..}
      --    instance C MyInt where {..}
      --
      -- Test cases: drvfail015, mod42, TidyClassKinds, tcfail139
      | InstHeadTySynArgs
      -- | Instance head was not of the form @T a1 ... an@,
      -- where @a1, ..., an@ are all type variables or literals.
      --
      -- Example:
      --
      --    instance Num [Int] where {..}
      --
      -- Test cases: mod41, mod42, tcfail044, tcfail047.
      | InstHeadNonTyVarArgs
      -- | Multi-param instance without -XMultiParamTypeClasses.
      --
      -- Example:
      --
      --  instance C a b where {..}
      --
      -- Test case: IllegalMultiParamInstance
      | InstHeadMultiParam
      deriving (forall x.
     IllegalInstanceHeadReason -> Rep IllegalInstanceHeadReason x)
    -> (forall x.
        Rep IllegalInstanceHeadReason x -> IllegalInstanceHeadReason)
    -> Generic IllegalInstanceHeadReason
    forall x.
    Rep IllegalInstanceHeadReason x -> IllegalInstanceHeadReason
    forall x.
    IllegalInstanceHeadReason -> Rep IllegalInstanceHeadReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x.
    IllegalInstanceHeadReason -> Rep IllegalInstanceHeadReason x
    from :: forall x.
    IllegalInstanceHeadReason -> Rep IllegalInstanceHeadReason x
    $cto :: forall x.
    Rep IllegalInstanceHeadReason x -> IllegalInstanceHeadReason
    to :: forall x.
    Rep IllegalInstanceHeadReason x -> IllegalInstanceHeadReason
    Generic

    -- | Why is a (type or data) family instance invalid?
    data IllegalFamilyInstanceReason
      {-| A top-level family instance for a 'TyCon' that isn't a family 'TyCon'.

        Example:

          data D a = MkD
          type instance D Int = Bool

        Test case: indexed-types/should_fail/T3092
      -}
      = NotAFamilyTyCon
          !TypeOrData -- ^ was this a 'type' or a 'data' instance?
          !TyCon
      {-| A top-level (open) type family instance for a closed type family.

        Test cases:
          indexed-types/should_fail/Overlap7
          indexed-types/should_fail/Overlap3
      -}
      | NotAnOpenFamilyTyCon !TyCon

      {-| A family instance was declared for a family of a different kind,
          e.g. a data instance for a type family 'TyCon'.

         Test cases:
           T9896, SimpleFail3a
      -}
      | FamilyCategoryMismatch !TyCon -- ^ The family tycon

      {-| A family instance was declared with a different number of arguments
          than expected.
          See Note [Oversaturated type family equations] in "GHC.Tc.Validity".

        Test cases:
          TyFamArity1, TyFamArity2, T11136, Overlap4, AssocTyDef05, AssocTyDef06,
          T14110
      -}
      | FamilyArityMismatch !TyCon -- ^ The family tycon
                            !Arity -- ^ The right number of parameters

      {-| A closed type family equation used a different name than the parent family.

        Example:

          type family F a where
            G Int = Bool

        Test cases:
          Overlap5, T15362, T16002, T20260, T11623
      -}
      | TyFamNameMismatch !Name -- ^ The family name
                          !Name -- ^ The name used in the equation

      -- | There are out-of-scope type variables in the right-hand side
      -- of an associated type or data family instance.
      --
      -- Example:
      --
      --    instance forall a. C Int where
      --      data instance D Int = MkD1 a
      --
      -- Test cases: indexed-types/should_fail/T5515, polykinds/T9574, rename/should_fail/T18021
      | FamInstRHSOutOfScopeTyVars
          !(Maybe (TyCon, [Type], TyVarSet))
            -- ^ family 'TyCon', arguments, and set of "dodgy" type variables
            -- See Note [Dodgy binding sites in type family instances]
            -- in GHC.Tc.Validity
          !(NE.NonEmpty Name) -- ^ the out-of-scope type variables

      | FamInstLHSUnusedBoundTyVars
          !(NE.NonEmpty InvalidFamInstQTv) -- ^ the unused bound type variables

      | InvalidAssoc !InvalidAssoc
      deriving (forall x.
     IllegalFamilyInstanceReason -> Rep IllegalFamilyInstanceReason x)
    -> (forall x.
        Rep IllegalFamilyInstanceReason x -> IllegalFamilyInstanceReason)
    -> Generic IllegalFamilyInstanceReason
    forall x.
    Rep IllegalFamilyInstanceReason x -> IllegalFamilyInstanceReason
    forall x.
    IllegalFamilyInstanceReason -> Rep IllegalFamilyInstanceReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x.
    IllegalFamilyInstanceReason -> Rep IllegalFamilyInstanceReason x
    from :: forall x.
    IllegalFamilyInstanceReason -> Rep IllegalFamilyInstanceReason x
    $cto :: forall x.
    Rep IllegalFamilyInstanceReason x -> IllegalFamilyInstanceReason
    to :: forall x.
    Rep IllegalFamilyInstanceReason x -> IllegalFamilyInstanceReason
    Generic

    -- | A quantified type variable in a type or data family equation that
    -- is either not bound in any LHS patterns or not used in the RHS (or both).
    data InvalidFamInstQTv
      = InvalidFamInstQTv
        { InvalidFamInstQTv -> TcTyVar
    ifiqtv :: TcTyVar
        , InvalidFamInstQTv -> Bool
    ifiqtv_user_written :: Bool
           -- ^ Did the user write this type variable, or was introduced by GHC?
           -- For example: with @-XPolyKinds@, in @type instance forall a. F = ()@,
           -- we have a user-written @a@ but GHC introduces a kind variable @k@
           -- as well. See #23734.
        , InvalidFamInstQTv -> InvalidFamInstQTvReason
    ifiqtv_reason       :: InvalidFamInstQTvReason
          -- ^ For what reason was the quantified type variable invalid?
        }

    data InvalidFamInstQTvReason
      -- | A dodgy binder, i.e. a variable that syntactically appears in
      -- LHS patterns but only in non-injective positions.
      --
      -- See Note [Dodgy binding sites in type family instances]
      -- in GHC.Tc.Validity.
      = InvalidFamInstQTvDodgy
      -- | A quantified type variable in a type or data family equation
      -- that is not bound in any LHS patterns.
      | InvalidFamInstQTvNotBoundInPats
      -- | A quantified type variable in a type or data family equation
      -- that is not used on the RHS.
      | InvalidFamInstQTvNotUsedInRHS

    -- The 'check_tvs' function in 'GHC.Tc.Validity.checkFamPatBinders'
    -- uses 'getSrcSpan', so this 'NamedThing' instance is convenient.
    instance NamedThing InvalidFamInstQTv where
      getName :: InvalidFamInstQTv -> Name
    getName = TcTyVar -> Name
    forall a. NamedThing a => a -> Name
    getName (TcTyVar -> Name)
    -> (InvalidFamInstQTv -> TcTyVar) -> InvalidFamInstQTv -> Name
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . InvalidFamInstQTv -> TcTyVar
    ifiqtv

    data InvalidAssoc
      -- | An invalid associated family instance.
      --
      -- See t'InvalidAssocInstance'.Builder
      = InvalidAssocInstance !InvalidAssocInstance
      -- | An invalid associated family default declaration.
      --
      -- See t'InvalidAssocDefault'.
      | InvalidAssocDefault  !InvalidAssocDefault
      deriving (forall x. InvalidAssoc -> Rep InvalidAssoc x)
    -> (forall x. Rep InvalidAssoc x -> InvalidAssoc)
    -> Generic InvalidAssoc
    forall x. Rep InvalidAssoc x -> InvalidAssoc
    forall x. InvalidAssoc -> Rep InvalidAssoc x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. InvalidAssoc -> Rep InvalidAssoc x
    from :: forall x. InvalidAssoc -> Rep InvalidAssoc x
    $cto :: forall x. Rep InvalidAssoc x -> InvalidAssoc
    to :: forall x. Rep InvalidAssoc x -> InvalidAssoc
    Generic

    -- | The reason that an associated family instance was invalid.
    data InvalidAssocInstance
      -- | A class instance is missing its expected associated type/data instance.
      --
      -- Test cases: deriving/should_compile/T14094
      --             indexed-types/should_compile/Simple2
      --             typecheck/should_compile/tc254
      = AssocInstanceMissing !Name

      -- | A top-level instance for an associated family 'TyCon'.
      --
      -- Example:
      --
      --  class C a where { type T a }
      --  instance T Int = Bool
      --
      -- Test case: indexed-types/should_fail/SimpleFail7
      | AssocInstanceNotInAClass !TyCon

      -- | An associated type instance is provided for a class that doesn't have
      -- that associated type.
      --
      -- Examples(s):
      --   $(do d <- instanceD (cxt []) (conT ''Eq `appT` conT ''Foo)
      --               [tySynInstD $ tySynEqn Nothing (conT ''Rep `appT` conT ''Foo) (conT ''Maybe)]
      --        return [d])
      --   ======>
      --   instance Eq Foo where
      --     type Rep Foo = Maybe
      --
      -- Test cases: th/T12387a
      | AssocNotInThisClass !Class !TyCon
      -- | An associated family instance does not mention any of the parent 'Class'
      -- 'TyVar's.
      --
      -- Test cases: T2888, T9167, T12867
      | AssocNoClassTyVar !Class !TyCon

      | AssocTyVarsDontMatch
          !ForAllTyFlag
          !TyCon  -- ^ family 'TyCon'
          ![Type] -- ^ expected type arguments
          ![Type] -- ^ actual type arguments
      deriving (forall x. InvalidAssocInstance -> Rep InvalidAssocInstance x)
    -> (forall x. Rep InvalidAssocInstance x -> InvalidAssocInstance)
    -> Generic InvalidAssocInstance
    forall x. Rep InvalidAssocInstance x -> InvalidAssocInstance
    forall x. InvalidAssocInstance -> Rep InvalidAssocInstance x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. InvalidAssocInstance -> Rep InvalidAssocInstance x
    from :: forall x. InvalidAssocInstance -> Rep InvalidAssocInstance x
    $cto :: forall x. Rep InvalidAssocInstance x -> InvalidAssocInstance
    to :: forall x. Rep InvalidAssocInstance x -> InvalidAssocInstance
    Generic

    -- | The reason that an associated family default declaration was invalid.
    data InvalidAssocDefault
        -- | An associated family default declaration for something that isn't
        -- an associated family.
      = AssocDefaultNotAssoc !Name -- ^ 'Class' 'Name'
                             !Name -- ^ 'TyCon' 'Name'
        -- | Multiple default declarations were given for an associated
        -- family instance.
        --
        -- Test cases: none.
      | AssocMultipleDefaults !Name
        -- | Invalid arguments in an associated family instance.
        --
        -- See t'AssocDefaultBadArgs'.
      | AssocDefaultBadArgs !TyCon ![Type] AssocDefaultBadArgs
      deriving (forall x. InvalidAssocDefault -> Rep InvalidAssocDefault x)
    -> (forall x. Rep InvalidAssocDefault x -> InvalidAssocDefault)
    -> Generic InvalidAssocDefault
    forall x. Rep InvalidAssocDefault x -> InvalidAssocDefault
    forall x. InvalidAssocDefault -> Rep InvalidAssocDefault x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. InvalidAssocDefault -> Rep InvalidAssocDefault x
    from :: forall x. InvalidAssocDefault -> Rep InvalidAssocDefault x
    $cto :: forall x. Rep InvalidAssocDefault x -> InvalidAssocDefault
    to :: forall x. Rep InvalidAssocDefault x -> InvalidAssocDefault
    Generic

    -- | Invalid arguments in an associated family instance declaration.
    data AssocDefaultBadArgs
      -- | An argument which isn't a type variable in an associated
      -- family instance default declaration.
      = AssocDefaultNonTyVarArg !(Type, ForAllTyFlag)
      -- | Duplicate occurrence of a type variable in an associated
      -- family instance default declaration.
      | AssocDefaultDuplicateTyVars !(NE.NonEmpty (TyCoVar, ForAllTyFlag))
      deriving (forall x. AssocDefaultBadArgs -> Rep AssocDefaultBadArgs x)
    -> (forall x. Rep AssocDefaultBadArgs x -> AssocDefaultBadArgs)
    -> Generic AssocDefaultBadArgs
    forall x. Rep AssocDefaultBadArgs x -> AssocDefaultBadArgs
    forall x. AssocDefaultBadArgs -> Rep AssocDefaultBadArgs x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. AssocDefaultBadArgs -> Rep AssocDefaultBadArgs x
    from :: forall x. AssocDefaultBadArgs -> Rep AssocDefaultBadArgs x
    $cto :: forall x. Rep AssocDefaultBadArgs x -> AssocDefaultBadArgs
    to :: forall x. Rep AssocDefaultBadArgs x -> AssocDefaultBadArgs
    Generic

    -- | A type representing whether or not the input type has associated data family instances.
    data HasAssociatedDataFamInsts
      = YesHasAdfs
      | NoHasAdfs
      deriving HasAssociatedDataFamInsts -> HasAssociatedDataFamInsts -> Bool
    (HasAssociatedDataFamInsts -> HasAssociatedDataFamInsts -> Bool)
    -> (HasAssociatedDataFamInsts -> HasAssociatedDataFamInsts -> Bool)
    -> Eq HasAssociatedDataFamInsts
    forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
    $c== :: HasAssociatedDataFamInsts -> HasAssociatedDataFamInsts -> Bool
    == :: HasAssociatedDataFamInsts -> HasAssociatedDataFamInsts -> Bool
    $c/= :: HasAssociatedDataFamInsts -> HasAssociatedDataFamInsts -> Bool
    /= :: HasAssociatedDataFamInsts -> HasAssociatedDataFamInsts -> Bool
    Eq

    hasAssociatedDataFamInsts :: Bool -> HasAssociatedDataFamInsts
    hasAssociatedDataFamInsts :: Bool -> HasAssociatedDataFamInsts
    hasAssociatedDataFamInsts Bool
    True = HasAssociatedDataFamInsts
    YesHasAdfs
    hasAssociatedDataFamInsts Bool
    False = HasAssociatedDataFamInsts
    NoHasAdfs

    -- | If 'YesAssocTyLastVarInKind', the associated type of a typeclass
    -- contains the last type variable of the class in a kind, which is not (yet) allowed
    -- by GHC.
    data AssociatedTyLastVarInKind
      = YesAssocTyLastVarInKind !TyCon -- ^ The associated type family of the class
      | NoAssocTyLastVarInKind
      deriving AssociatedTyLastVarInKind -> AssociatedTyLastVarInKind -> Bool
    (AssociatedTyLastVarInKind -> AssociatedTyLastVarInKind -> Bool)
    -> (AssociatedTyLastVarInKind -> AssociatedTyLastVarInKind -> Bool)
    -> Eq AssociatedTyLastVarInKind
    forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
    $c== :: AssociatedTyLastVarInKind -> AssociatedTyLastVarInKind -> Bool
    == :: AssociatedTyLastVarInKind -> AssociatedTyLastVarInKind -> Bool
    $c/= :: AssociatedTyLastVarInKind -> AssociatedTyLastVarInKind -> Bool
    /= :: AssociatedTyLastVarInKind -> AssociatedTyLastVarInKind -> Bool
    Eq

    associatedTyLastVarInKind :: Maybe TyCon -> AssociatedTyLastVarInKind
    associatedTyLastVarInKind :: Maybe TyCon -> AssociatedTyLastVarInKind
    associatedTyLastVarInKind (Just TyCon
    tc) = TyCon -> AssociatedTyLastVarInKind
    YesAssocTyLastVarInKind TyCon
    tc
    associatedTyLastVarInKind Maybe TyCon
    Nothing   = AssociatedTyLastVarInKind
    NoAssocTyLastVarInKind

    -- | If 'NoAssociatedTyNotParamOverLastTyVar', the associated type of a
    -- typeclass is not parameterized over the last type variable of the class
    data AssociatedTyNotParamOverLastTyVar
      = YesAssociatedTyNotParamOverLastTyVar !TyCon -- ^ The associated type family of the class
      | NoAssociatedTyNotParamOverLastTyVar
      deriving AssociatedTyNotParamOverLastTyVar
    -> AssociatedTyNotParamOverLastTyVar -> Bool
    (AssociatedTyNotParamOverLastTyVar
     -> AssociatedTyNotParamOverLastTyVar -> Bool)
    -> (AssociatedTyNotParamOverLastTyVar
        -> AssociatedTyNotParamOverLastTyVar -> Bool)
    -> Eq AssociatedTyNotParamOverLastTyVar
    forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
    $c== :: AssociatedTyNotParamOverLastTyVar
    -> AssociatedTyNotParamOverLastTyVar -> Bool
    == :: AssociatedTyNotParamOverLastTyVar
    -> AssociatedTyNotParamOverLastTyVar -> Bool
    $c/= :: AssociatedTyNotParamOverLastTyVar
    -> AssociatedTyNotParamOverLastTyVar -> Bool
    /= :: AssociatedTyNotParamOverLastTyVar
    -> AssociatedTyNotParamOverLastTyVar -> Bool
    Eq

    associatedTyNotParamOverLastTyVar :: Maybe TyCon -> AssociatedTyNotParamOverLastTyVar
    associatedTyNotParamOverLastTyVar :: Maybe TyCon -> AssociatedTyNotParamOverLastTyVar
    associatedTyNotParamOverLastTyVar (Just TyCon
    tc) = TyCon -> AssociatedTyNotParamOverLastTyVar
    YesAssociatedTyNotParamOverLastTyVar TyCon
    tc
    associatedTyNotParamOverLastTyVar Maybe TyCon
    Nothing   = AssociatedTyNotParamOverLastTyVar
    NoAssociatedTyNotParamOverLastTyVar

    -- | What kind of thing is missing a type signature?
    --
    -- Used for reporting @"missing signature"@ warnings, see
    -- 'tcRnMissingSignature'.
    data MissingSignature
      = MissingTopLevelBindingSig Name Type
      | MissingPatSynSig PatSyn
      | MissingTyConKindSig
          TyCon
          Bool -- ^ whether -XCUSKs is enabled

    -- | Is the object we are dealing with exported or not?
    --
    -- Used for reporting @"missing signature"@ warnings, see
    -- 'TcRnMissingSignature'.
    data Exported
      = IsNotExported
      | IsExported
      deriving Exported -> Exported -> Bool
    (Exported -> Exported -> Bool)
    -> (Exported -> Exported -> Bool) -> Eq Exported
    forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
    $c== :: Exported -> Exported -> Bool
    == :: Exported -> Exported -> Bool
    $c/= :: Exported -> Exported -> Bool
    /= :: Exported -> Exported -> Bool
    Eq

    instance Outputable Exported where
      ppr :: Exported -> SDoc
    ppr Exported
    IsNotExported = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "IsNotExported"
      ppr Exported
    IsExported    = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "IsExported"

    -- | What declarations were not allowed in an hs-boot or hsig file?
    data BadBootDecls
      = BootBindsPs      !(NE.NonEmpty (LHsBindLR GhcRn GhcPs))
      | BootBindsRn      !(NE.NonEmpty (LHsBindLR GhcRn GhcRn))
      | BootInstanceSigs !(NE.NonEmpty (LSig GhcRn))
      | BootFamInst      !TyCon
      | BootSpliceDecls  !(NE.NonEmpty (LocatedA (HsUntypedSplice GhcPs)))
      | BootForeignDecls !(NE.NonEmpty (LForeignDecl GhcRn))
      | BootDefaultDecls !(NE.NonEmpty (LDefaultDecl GhcRn))
      | BootRuleDecls    !(NE.NonEmpty (LRuleDecls GhcRn))

    -- | A mismatch between an hs-boot or signature file and its implementing module.
    data BootMismatch
      -- | Something defined or exported by an hs-boot or signature file
      -- is missing from the implementing module.
      = MissingBootThing !Name !MissingBootThing

      -- | A typeclass instance is declared in the hs-boot file but
      -- it is not present in the implementing module.
      | MissingBootInstance !DFunId -- ^ the boot instance 'DFunId'
        -- NB: we never trigger this for hsig files, as in that case we do
        -- a full round of constraint solving, and a missing instance gets reported
        -- as an unsolved Wanted constraint with a 'InstProvidedOrigin' 'CtOrigin'.
        -- See GHC.Tc.Utils.Backpack.check_inst.

      -- | A mismatch between an hsig file and its implementing module
      -- in the 'Name' that a particular re-export refers to.
      | BadReexportedBootThing !Name !Name

      -- | A mismatch between the declaration of something in the hs-boot or
      -- signature file and its implementation, e.g. a type mismatch or
      -- a type family implemented as a class.
      | BootMismatch
          !TyThing -- ^ boot thing
          !TyThing -- ^ real thing
          !BootMismatchWhat
      deriving (forall x. BootMismatch -> Rep BootMismatch x)
    -> (forall x. Rep BootMismatch x -> BootMismatch)
    -> Generic BootMismatch
    forall x. Rep BootMismatch x -> BootMismatch
    forall x. BootMismatch -> Rep BootMismatch x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. BootMismatch -> Rep BootMismatch x
    from :: forall x. BootMismatch -> Rep BootMismatch x
    $cto :: forall x. Rep BootMismatch x -> BootMismatch
    to :: forall x. Rep BootMismatch x -> BootMismatch
    Generic

    -- | Something from the hs-boot or signature file is missing from the
    -- implementing module.
    data MissingBootThing
      -- | Something defined in the hs-boot or signature file is not defined in the
      -- implementing module.
      = MissingBootDefinition
      -- | Something exported by the hs-boot or signature file is not exported by the
      -- implementing module.
      | MissingBootExport
      deriving (forall x. MissingBootThing -> Rep MissingBootThing x)
    -> (forall x. Rep MissingBootThing x -> MissingBootThing)
    -> Generic MissingBootThing
    forall x. Rep MissingBootThing x -> MissingBootThing
    forall x. MissingBootThing -> Rep MissingBootThing x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. MissingBootThing -> Rep MissingBootThing x
    from :: forall x. MissingBootThing -> Rep MissingBootThing x
    $cto :: forall x. Rep MissingBootThing x -> MissingBootThing
    to :: forall x. Rep MissingBootThing x -> MissingBootThing
    Generic

    missingBootThing :: HsBootOrSig -> Name -> MissingBootThing -> TcRnMessage
    missingBootThing :: HsBootOrSig -> Name -> MissingBootThing -> TcRnMessage
    missingBootThing HsBootOrSig
    src Name
    nm MissingBootThing
    thing =
      HsBootOrSig -> BootMismatch -> TcRnMessage
    TcRnBootMismatch HsBootOrSig
    src (Name -> MissingBootThing -> BootMismatch
    MissingBootThing Name
    nm MissingBootThing
    thing)

    -- | A mismatch of two 'TyThing's between an hs-boot or signature file
    -- and its implementing module.
    data BootMismatchWhat
      -- | The 'Id's have different types.
      = BootMismatchedIdTypes !Id -- ^ boot 'Id'
                              !Id -- ^ real 'Id'
      -- | Two 'TyCon's aren't compatible.
      | BootMismatchedTyCons !TyCon -- ^ boot 'TyCon'
                             !TyCon -- ^ real 'TyCon'
                             !(NE.NonEmpty BootTyConMismatch)
      deriving (forall x. BootMismatchWhat -> Rep BootMismatchWhat x)
    -> (forall x. Rep BootMismatchWhat x -> BootMismatchWhat)
    -> Generic BootMismatchWhat
    forall x. Rep BootMismatchWhat x -> BootMismatchWhat
    forall x. BootMismatchWhat -> Rep BootMismatchWhat x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. BootMismatchWhat -> Rep BootMismatchWhat x
    from :: forall x. BootMismatchWhat -> Rep BootMismatchWhat x
    $cto :: forall x. Rep BootMismatchWhat x -> BootMismatchWhat
    to :: forall x. Rep BootMismatchWhat x -> BootMismatchWhat
    Generic

    -- | An error in the implementation of an abstract datatype using
    -- a type synonym.
    data SynAbstractDataError
      -- | The type synony was not nullary.
      = SynAbsDataTySynNotNullary
      -- | The type synonym RHS contained invalid types, e.g.
      -- a type family or a forall.
      | SynAbstractDataInvalidRHS !(NE.NonEmpty Type)

    -- | Mismatched implementation of a 'TyCon' in an hs-boot or signature file.
    data BootTyConMismatch
      -- | The 'TyCon' kinds differ.
      = TyConKindMismatch
      -- | The 'TyCon' 'Role's aren't compatible.
      | TyConRoleMismatch !Bool -- ^ True <=> role subtype check
      -- | Two type synonyms have different RHSs.
      | TyConSynonymMismatch !Kind !Kind
      -- | The two 'TyCon's are of a different flavour, e.g. one is
      -- a data family and the other is a type family.
      | TyConFlavourMismatch !FamTyConFlav !FamTyConFlav
      -- | The equations of a type family don't match.
      | TyConAxiomMismatch !(BootListMismatches CoAxBranch BootAxiomBranchMismatch)
      -- | The type family injectivity annotations don't match.
      | TyConInjectivityMismatch
      -- | The 'TyCon's are both datatype 'TyCon's, but they have diferent 'DataCon's.
      | TyConMismatchedData !AlgTyConRhs !AlgTyConRhs !BootDataMismatch
      -- | The 'TyCon's are both 'Class' 'TyCon's, but the classes don't match.
      | TyConMismatchedClasses !Class !Class !BootClassMismatch
      -- | The 'TyCon's are something completely different.
      | TyConsVeryDifferent
      -- | An abstract 'TyCon' is implemented using a type synonym in an invalid
      -- manner. See 'SynAbstractDataError'.
      | SynAbstractData !SynAbstractDataError

    -- | Utility datatype to record errors when checking compatibity
    -- between two lists of things, e.g. class methods, associated types,
    -- type family equations, etc.
    data BootListMismatch item err
      -- | Different number of items.
      = MismatchedLength
      -- | The item at the given position in the list differs.
      | MismatchedThing !Int !item !item !err

    type BootListMismatches item err =
      NE.NonEmpty (BootListMismatch item err)

    data BootAxiomBranchMismatch
      -- | The quantified variables in an equation don't match.
      --
      -- Example: the quantification of @a@ in
      --
      --   @type family F a where { forall a. F a = Maybe a }@
      = MismatchedAxiomBinders
      -- | The LHSs of an equation don't match.
      | MismatchedAxiomLHS
      -- | The RHSs of an equation don't match.
      | MismatchedAxiomRHS

    -- | A mismatch in a class, between its declaration in an hs-boot or signature
    -- file, and its implementation in a source Haskell file.
    data BootClassMismatch
      -- | The class methods don't match.
      = MismatchedMethods !(BootListMismatches ClassOpItem BootMethodMismatch)
      -- | The associated types don't match.
      | MismatchedATs !(BootListMismatches ClassATItem BootATMismatch)
      -- | The functional dependencies don't match.
      | MismatchedFunDeps
      -- | The superclasses don't match.
      | MismatchedSuperclasses
      -- | The @MINIMAL@ pragmas are not compatible.
      | MismatchedMinimalPragmas

    -- | A mismatch in a class method, between its declaration in an hs-boot or signature
    -- file, and its implementation in a source Haskell file.
    data BootMethodMismatch
      -- | The class method names are different.
      = MismatchedMethodNames
      -- | The types of a class method are different.
      | MismatchedMethodTypes !Type !Type
      -- | The default method types are not compatible.
      | MismatchedDefaultMethods !Bool -- ^ True <=> subtype check

    -- | A mismatch in an associated type of a class, between its declaration
    -- in an hs-boot or signature file, and its implementation in a source Haskell file.
    data BootATMismatch
      -- | Two associated types don't match.
      = MismatchedTyConAT !BootTyConMismatch
      -- | Two associated type defaults don't match.
      | MismatchedATDefaultType

    -- | A mismatch in a datatype declaration, between an hs-boot file or signature
    -- file and its implementing module.
    data BootDataMismatch
      -- | A datatype is implemented as a newtype or vice-versa.
      = MismatchedNewtypeVsData
      -- | The constructors don't match.
      | MismatchedConstructors !(BootListMismatches DataCon BootDataConMismatch)
      -- | The datatype contexts differ.
      | MismatchedDatatypeContexts

    -- | A mismatch in a data constrcutor, between its declaration in an hs-boot
    -- file or signature file, and its implementation in a source Haskell module.
    data BootDataConMismatch
      -- | The 'Name's of the 'DataCon's differ.
      = MismatchedDataConNames
      -- | The fixities of the 'DataCon's differ.
      | MismatchedDataConFixities
      -- | The strictness annotations of the 'DataCon's differ.
      | MismatchedDataConBangs
      -- | The 'DataCon's have different field labels.
      | MismatchedDataConFieldLabels
      -- | The 'DataCon's have incompatible types.
      | MismatchedDataConTypes

    --------------------------------------------------------------------------------
    --
    --     Errors used in GHC.Tc.Errors
    --
    --------------------------------------------------------------------------------

    {- Note [Error report]
    ~~~~~~~~~~~~~~~~~~~~~~
    The idea is that error msgs are divided into three parts: the main msg, the
    context block ("In the second argument of ..."), and the relevant bindings
    block, which are displayed in that order, with a mark to divide them. The
    the main msg ('report_important') varies depending on the error
    in question, but context and relevant bindings are always the same, which
    should simplify visual parsing.

    See 'GHC.Tc.Errors.Types.SolverReport' and 'GHC.Tc.Errors.mkErrorReport'.
    -}

    -- | A collection of main error messages and supplementary information.
    --
    -- In practice, we will:
    --  - display the important messages first,
    --  - then the error context (e.g. by way of a call to 'GHC.Tc.Errors.mkErrorReport'),
    --  - then the supplementary information (e.g. relevant bindings, valid hole fits),
    --  - then the hints ("Possible fix: ...").
    --
    -- So this is mostly just a way of making sure that the error context appears
    -- early on rather than at the end of the message.
    --
    -- See Note [Error report] for details.
    data SolverReport
      = SolverReport
      { SolverReport -> SolverReportWithCtxt
    sr_important_msg :: SolverReportWithCtxt
      , SolverReport -> [SolverReportSupplementary]
    sr_supplementary :: [SolverReportSupplementary]
      }

    -- | Additional information to print in a 'SolverReport', after the
    -- important messages and after the error context.
    --
    -- See Note [Error report].
    data SolverReportSupplementary
      = SupplementaryBindings RelevantBindings
      | SupplementaryHoleFits ValidHoleFits
      | SupplementaryCts      [(PredType, RealSrcSpan)]

    -- | A 'TcSolverReportMsg', together with context (e.g. enclosing implication constraints)
    -- that are needed in order to report it.
    data SolverReportWithCtxt =
      SolverReportWithCtxt
        { SolverReportWithCtxt -> SolverReportErrCtxt
    reportContext :: SolverReportErrCtxt
           -- ^ Context for what we wish to report.
           -- This can change as we enter implications, so is
           -- stored alongside the content.
        , SolverReportWithCtxt -> TcSolverReportMsg
    reportContent :: TcSolverReportMsg
          -- ^ The content of the message to report.
        }
      deriving (forall x. SolverReportWithCtxt -> Rep SolverReportWithCtxt x)
    -> (forall x. Rep SolverReportWithCtxt x -> SolverReportWithCtxt)
    -> Generic SolverReportWithCtxt
    forall x. Rep SolverReportWithCtxt x -> SolverReportWithCtxt
    forall x. SolverReportWithCtxt -> Rep SolverReportWithCtxt x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. SolverReportWithCtxt -> Rep SolverReportWithCtxt x
    from :: forall x. SolverReportWithCtxt -> Rep SolverReportWithCtxt x
    $cto :: forall x. Rep SolverReportWithCtxt x -> SolverReportWithCtxt
    to :: forall x. Rep SolverReportWithCtxt x -> SolverReportWithCtxt
    Generic

    -- | Context needed when reporting a 'TcSolverReportMsg', such as
    -- the enclosing implication constraints or whether we are deferring type errors.
    data SolverReportErrCtxt
        = CEC { SolverReportErrCtxt -> [Implication]
    cec_encl :: [Implication]  -- ^ Enclosing implications
                                           --   (innermost first)
                                           -- ic_skols and givens are tidied, rest are not
              , SolverReportErrCtxt -> TidyEnv
    cec_tidy  :: TidyEnv

              , SolverReportErrCtxt -> EvBindsVar
    cec_binds :: EvBindsVar    -- ^ We make some errors (depending on cec_defer)
                                           -- into warnings, and emit evidence bindings
                                           -- into 'cec_binds' for unsolved constraints

              , SolverReportErrCtxt -> DiagnosticReason
    cec_defer_type_errors :: DiagnosticReason -- ^ Whether to defer type errors until runtime

              -- We might throw a warning on an error when encountering a hole,
              -- depending on the type of hole (expression hole, type hole, out of scope hole).
              -- We store the reasons for reporting a diagnostic for each type of hole.
              , SolverReportErrCtxt -> DiagnosticReason
    cec_expr_holes :: DiagnosticReason -- ^ Reason for reporting holes in expressions.
              , SolverReportErrCtxt -> DiagnosticReason
    cec_type_holes :: DiagnosticReason -- ^ Reason for reporting holes in types.
              , SolverReportErrCtxt -> DiagnosticReason
    cec_out_of_scope_holes :: DiagnosticReason -- ^ Reason for reporting out of scope holes.

              , SolverReportErrCtxt -> Bool
    cec_warn_redundant :: Bool    -- ^ True <=> -Wredundant-constraints
              , SolverReportErrCtxt -> Bool
    cec_expand_syns    :: Bool    -- ^ True <=> -fprint-expanded-synonyms

              , SolverReportErrCtxt -> Bool
    cec_suppress :: Bool    -- ^ True <=> More important errors have occurred,
                                        --            so create bindings if need be, but
                                        --            don't issue any more errors/warnings
                                        -- See Note [Suppressing error messages]
          }

    getUserGivens :: SolverReportErrCtxt -> [UserGiven]
    -- One item for each enclosing implication
    getUserGivens :: SolverReportErrCtxt -> [Implication]
    getUserGivens (CEC {cec_encl :: SolverReportErrCtxt -> [Implication]
    cec_encl = [Implication]
    implics}) = [Implication] -> [Implication]
    getUserGivensFromImplics [Implication]
    implics

    ----------------------------------------------------------------------------
    --
    --   ErrorItem
    --
    ----------------------------------------------------------------------------

    -- | A predicate with its arising location; used to encapsulate a constraint
    -- that will give rise to a diagnostic.
    data ErrorItem
    -- We could perhaps use Ct here (and indeed used to do exactly that), but
    -- having a separate type gives to denote errors-in-formation gives us
    -- a nice place to do pre-processing, such as calculating ei_suppress.
    -- Perhaps some day, an ErrorItem could eventually evolve to contain
    -- the error text (or some representation of it), so we can then have all
    -- the errors together when deciding which to report.
      = EI { ErrorItem -> Type
    ei_pred     :: PredType         -- report about this
             -- The ei_pred field will never be an unboxed equality with
             -- a (casted) tyvar on the right; this is guaranteed by the solver
           , ErrorItem -> Maybe TcEvDest
    ei_evdest   :: Maybe TcEvDest
             -- ^ for Wanteds, where to put the evidence
             --   for Givens, Nothing
           , ErrorItem -> CtFlavour
    ei_flavour  :: CtFlavour
           , ErrorItem -> CtLoc
    ei_loc      :: CtLoc
           , ErrorItem -> Maybe CtIrredReason
    ei_m_reason :: Maybe CtIrredReason  -- if this ErrorItem was made from a
                                                 -- CtIrred, this stores the reason
           , ErrorItem -> Bool
    ei_suppress :: Bool    -- Suppress because of Note [Wanteds rewrite Wanteds]
                                    -- in GHC.Tc.Constraint
           }

    instance Outputable ErrorItem where
      ppr :: ErrorItem -> SDoc
    ppr (EI { ei_pred :: ErrorItem -> Type
    ei_pred     = Type
    pred
              , ei_evdest :: ErrorItem -> Maybe TcEvDest
    ei_evdest   = Maybe TcEvDest
    m_evdest
              , ei_flavour :: ErrorItem -> CtFlavour
    ei_flavour  = CtFlavour
    flav
              , ei_suppress :: ErrorItem -> Bool
    ei_suppress = Bool
    supp })
        = SDoc
    pp_supp SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> CtFlavour -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr CtFlavour
    flav SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> Maybe TcEvDest -> SDoc
    forall {a}. Outputable a => Maybe a -> SDoc
    pp_dest Maybe TcEvDest
    m_evdest SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> Type -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Type
    pred
        where
          pp_dest :: Maybe a -> SDoc
    pp_dest Maybe a
    Nothing   = SDoc
    forall doc. IsOutput doc => doc
    empty
          pp_dest (Just a
    ev) = a -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr a
    ev SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> SDoc
    dcolon

          pp_supp :: SDoc
    pp_supp = if Bool
    supp then String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "suppress:" else SDoc
    forall doc. IsOutput doc => doc
    empty

    errorItemOrigin :: ErrorItem -> CtOrigin
    errorItemOrigin :: ErrorItem -> CtOrigin
    errorItemOrigin = CtLoc -> CtOrigin
    ctLocOrigin (CtLoc -> CtOrigin)
    -> (ErrorItem -> CtLoc) -> ErrorItem -> CtOrigin
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ErrorItem -> CtLoc
    ei_loc

    errorItemEqRel :: ErrorItem -> EqRel
    errorItemEqRel :: ErrorItem -> EqRel
    errorItemEqRel = Type -> EqRel
    predTypeEqRel (Type -> EqRel) -> (ErrorItem -> Type) -> ErrorItem -> EqRel
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ErrorItem -> Type
    ei_pred

    errorItemCtLoc :: ErrorItem -> CtLoc
    errorItemCtLoc :: ErrorItem -> CtLoc
    errorItemCtLoc = ErrorItem -> CtLoc
    ei_loc

    errorItemPred :: ErrorItem -> PredType
    errorItemPred :: ErrorItem -> Type
    errorItemPred = ErrorItem -> Type
    ei_pred

    {- Note [discardProvCtxtGivens]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    In most situations we call all enclosing implications "useful". There is one
    exception, and that is when the constraint that causes the error is from the
    "provided" context of a pattern synonym declaration:

      pattern Pat :: (Num a, Eq a) => Show a   => a -> Maybe a
                 --  required      => provided => type
      pattern Pat x <- (Just x, 4)

    When checking the pattern RHS we must check that it does actually bind all
    the claimed "provided" constraints; in this case, does the pattern (Just x, 4)
    bind the (Show a) constraint.  Answer: no!

    But the implication we generate for this will look like
       forall a. (Num a, Eq a) => [W] Show a
    because when checking the pattern we must make the required
    constraints available, since they are needed to match the pattern (in
    this case the literal '4' needs (Num a, Eq a)).

    BUT we don't want to suggest adding (Show a) to the "required" constraints
    of the pattern synonym, thus:
      pattern Pat :: (Num a, Eq a, Show a) => Show a => a -> Maybe a
    It would then typecheck but it's silly.  We want the /pattern/ to bind
    the alleged "provided" constraints, Show a.

    So we suppress that Implication in discardProvCtxtGivens.  It's
    painfully ad-hoc but the truth is that adding it to the "required"
    constraints would work.  Suppressing it solves two problems.  First,
    we never tell the user that we could not deduce a "provided"
    constraint from the "required" context. Second, we never give a
    possible fix that suggests to add a "provided" constraint to the
    "required" context.

    For example, without this distinction the above code gives a bad error
    message (showing both problems):

      error: Could not deduce (Show a) ... from the context: (Eq a)
             ... Possible fix: add (Show a) to the context of
             the signature for pattern synonym `Pat' ...
    -}

    discardProvCtxtGivens :: CtOrigin -> [UserGiven] -> [UserGiven]
    discardProvCtxtGivens :: CtOrigin -> [Implication] -> [Implication]
    discardProvCtxtGivens CtOrigin
    orig [Implication]
    givens  -- See Note [discardProvCtxtGivens]
      | ProvCtxtOrigin (PSB {psb_id :: forall idL idR. PatSynBind idL idR -> LIdP idL
    psb_id = L SrcSpanAnnN
    _ Name
    name}) <- CtOrigin
    orig
      = (Implication -> Bool) -> [Implication] -> [Implication]
    forall a. (a -> Bool) -> [a] -> [a]
    filterOut (Name -> Implication -> Bool
    discard Name
    name) [Implication]
    givens
      | Bool
    otherwise
      = [Implication]
    givens
      where
        discard :: Name -> Implication -> Bool
    discard Name
    n (Implic { ic_info :: Implication -> SkolemInfoAnon
    ic_info = SigSkol (PatSynCtxt Name
    n') Type
    _ [(Name, TcTyVar)]
    _ }) = Name
    n Name -> Name -> Bool
    forall a. Eq a => a -> a -> Bool
    == Name
    n'
        discard Name
    _ Implication
    _                                                  = Bool
    False

    -- | An error reported after constraint solving.
    -- This is usually, some sort of unsolved constraint error,
    -- but we try to be specific about the precise problem we encountered.
    data TcSolverReportMsg
      -- | Quantified variables appear out of dependency order.
      --
      -- Example:
      --
      --   forall (a :: k) k. ...
      --
      -- Test cases: BadTelescope2, T16418, T16247, T16726, T18451.
      = BadTelescope TyVarBndrs [TyCoVar]

      -- | We came across a custom type error and we have decided to report it.
      --
      -- Example:
      --
      --   type family F a where
      --     F a = TypeError (Text "error")
      --
      --   err :: F ()
      --   err = ()
      --
      -- Test cases: CustomTypeErrors0{1,2,3,4,5}, T12104.
      | UserTypeError ErrorMsgType -- ^ the message to report

      -- | Report a Wanted constraint of the form "Unsatisfiable msg".
      | UnsatisfiableError ErrorMsgType -- ^ the message to report

      -- | We want to report an out of scope variable or a typed hole.
      -- See 'HoleError'.
      | ReportHoleError Hole HoleError

      -- | Cannot unify a variable, because of a type mismatch.
      | CannotUnifyVariable
        { TcSolverReportMsg -> MismatchMsg
    mismatchMsg         :: MismatchMsg
        , TcSolverReportMsg -> CannotUnifyVariableReason
    cannotUnifyReason   :: CannotUnifyVariableReason }

      -- | A mismatch between two types.
      | Mismatch
         { mismatchMsg           :: MismatchMsg
         , TcSolverReportMsg -> Maybe TyVarInfo
    mismatchTyVarInfo     :: Maybe TyVarInfo
         , TcSolverReportMsg -> [AmbiguityInfo]
    mismatchAmbiguityInfo :: [AmbiguityInfo]
         , TcSolverReportMsg -> Maybe CoercibleMsg
    mismatchCoercibleInfo :: Maybe CoercibleMsg }

       -- | A violation of the representation-polymorphism invariants.
       --
       -- See 'FixedRuntimeRepErrorInfo' and 'FixedRuntimeRepContext' for more information.
      | FixedRuntimeRepError [FixedRuntimeRepErrorInfo]

      -- | An equality between two types is blocked on a kind equality
      -- between their kinds.
      --
      -- Test cases: none.
      | BlockedEquality ErrorItem
        -- These are for the "blocked" equalities, as described in
        -- Note [Equalities with incompatible kinds] in GHC.Tc.Solver.Equality,
        -- wrinkle (EIK2). There should always be another unsolved wanted around,
        -- which will ordinarily suppress this message. But this can still be printed out
        -- with -fdefer-type-errors (sigh), so we must produce a message.

      -- | Something was not applied to sufficiently many arguments.
      --
      --  Example:
      --
      --    instance Eq Maybe where {..}
      --
      -- Test case: T11563.
      | ExpectingMoreArguments Int TypedThing

      -- | Trying to use an unbound implicit parameter.
      --
      -- Example:
      --
      --    foo :: Int
      --    foo = ?param
      --
      -- Test case: tcfail130.
      | UnboundImplicitParams
          (NE.NonEmpty ErrorItem)

      -- | A constraint couldn't be solved because it contains
      -- ambiguous type variables.
      --
      -- Example:
      --
      --   class C a b where
      --     f :: (a,b)
      --
      --   x = fst f
      --
      --
      -- Test case: T4921.
      | AmbiguityPreventsSolvingCt
          ErrorItem -- ^ always a class constraint
          ([TyVar], [TyVar]) -- ^ ambiguous kind and type variables, respectively

      -- | Could not solve a constraint; there were several unifying candidate instances
      -- but no matching instances. This is used to report as much useful information
      -- as possible about why we couldn't choose any instance, e.g. because of
      -- ambiguous type variables.
      | CannotResolveInstance
        { TcSolverReportMsg -> ErrorItem
    cannotResolve_item         :: ErrorItem
        , TcSolverReportMsg -> [ClsInst]
    cannotResolve_unifiers     :: [ClsInst]
        , TcSolverReportMsg -> [ClsInst]
    cannotResolve_candidates   :: [ClsInst]
        , TcSolverReportMsg -> [ImportError]
    cannotResolve_importErrors :: [ImportError]
        , TcSolverReportMsg -> [GhcHint]
    cannotResolve_suggestions  :: [GhcHint]
        , TcSolverReportMsg -> RelevantBindings
    cannotResolve_relevant_bindings :: RelevantBindings }
          -- TODO: remove the fields of type [GhcHint] and RelevantBindings,
          -- in order to handle them uniformly with other diagnostic messages.

      -- | Could not solve a constraint using available instances
      -- because the instances overlap.
      --
      -- Test cases: tcfail118, tcfail121, tcfail218.
      | OverlappingInstances
        { TcSolverReportMsg -> ErrorItem
    overlappingInstances_item     :: ErrorItem
        , TcSolverReportMsg -> NonEmpty ClsInst
    overlappingInstances_matches  :: NE.NonEmpty ClsInst
        , TcSolverReportMsg -> [ClsInst]
    overlappingInstances_unifiers :: [ClsInst] }

      -- | Could not solve a constraint from instances because
      -- instances declared in a Safe module cannot overlap instances
      -- from other modules (with -XSafeHaskell).
      --
      -- Test cases: SH_Overlap{1,2,5,6,7,11}.
      | UnsafeOverlap
        { TcSolverReportMsg -> ErrorItem
    unsafeOverlap_item    :: ErrorItem
        , TcSolverReportMsg -> ClsInst
    unsafeOverlap_match   :: ClsInst
        , TcSolverReportMsg -> NonEmpty ClsInst
    unsafeOverlapped      :: NE.NonEmpty ClsInst }

      deriving (forall x. TcSolverReportMsg -> Rep TcSolverReportMsg x)
    -> (forall x. Rep TcSolverReportMsg x -> TcSolverReportMsg)
    -> Generic TcSolverReportMsg
    forall x. Rep TcSolverReportMsg x -> TcSolverReportMsg
    forall x. TcSolverReportMsg -> Rep TcSolverReportMsg x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. TcSolverReportMsg -> Rep TcSolverReportMsg x
    from :: forall x. TcSolverReportMsg -> Rep TcSolverReportMsg x
    $cto :: forall x. Rep TcSolverReportMsg x -> TcSolverReportMsg
    to :: forall x. Rep TcSolverReportMsg x -> TcSolverReportMsg
    Generic

    data MismatchMsg
      =  -- | Couldn't unify two types or kinds.
      --
      --  Example:
      --
      --    3 + 3# -- can't match a lifted type with an unlifted type
      --
      --  Test cases: T1396, T8263, ...
        BasicMismatch
          { MismatchMsg -> MismatchEA
    mismatch_ea           :: MismatchEA  -- ^ Should this be phrased in terms of expected vs actual?
          , MismatchMsg -> ErrorItem
    mismatch_item         :: ErrorItem   -- ^ The constraint in which the mismatch originated.
          , MismatchMsg -> Type
    mismatch_ty1          :: Type        -- ^ First type (the expected type if if mismatch_ea is True)
          , MismatchMsg -> Type
    mismatch_ty2          :: Type        -- ^ Second type (the actual type if mismatch_ea is True)
          , MismatchMsg -> Maybe WhenMatching
    mismatch_whenMatching :: Maybe WhenMatching
          , MismatchMsg -> Maybe SameOccInfo
    mismatch_mb_same_occ  :: Maybe SameOccInfo
          }

      -- | A type has an unexpected kind.
      --
      -- Test cases: T2994, T7609, ...
      | KindMismatch
          { MismatchMsg -> TypedThing
    kmismatch_what     :: TypedThing -- ^ What thing is 'kmismatch_actual' the kind of?
          , MismatchMsg -> Type
    kmismatch_expected :: Type
          , MismatchMsg -> Type
    kmismatch_actual   :: Type
          }
        -- TODO: combine with 'BasicMismatch'.

      -- | A mismatch between two types, which arose from a type equality.
      --
      -- Test cases: T1470, tcfail212.
      | TypeEqMismatch
          { MismatchMsg -> ErrorItem
    teq_mismatch_item     :: ErrorItem
          , MismatchMsg -> Type
    teq_mismatch_ty1      :: Type
          , MismatchMsg -> Type
    teq_mismatch_ty2      :: Type
          , MismatchMsg -> Type
    teq_mismatch_expected :: Type -- ^ The overall expected type
          , MismatchMsg -> Type
    teq_mismatch_actual   :: Type -- ^ The overall actual type
          , MismatchMsg -> Maybe TypedThing
    teq_mismatch_what     :: Maybe TypedThing -- ^ What thing is 'teq_mismatch_actual' the kind of?
          , MismatchMsg -> Maybe SameOccInfo
    teq_mb_same_occ       :: Maybe SameOccInfo
          }
        -- TODO: combine with 'BasicMismatch'.

      -- | Couldn't solve some Wanted constraints using the Givens.
      -- Used for messages such as @"No instance for ..."@ and
      -- @"Could not deduce ... from"@.
      | CouldNotDeduce
         { MismatchMsg -> [Implication]
    cnd_user_givens :: [Implication]
            -- | The Wanted constraints we couldn't solve.
            --
            -- N.B.: the 'ErrorItem' at the head of the list has been tidied,
            -- perhaps not the others.
         , MismatchMsg -> NonEmpty ErrorItem
    cnd_wanted      :: NE.NonEmpty ErrorItem

           -- | Some additional info consumed by 'mk_supplementary_ea_msg'.
         , MismatchMsg -> Maybe CND_Extra
    cnd_extra       :: Maybe CND_Extra
         }
      deriving (forall x. MismatchMsg -> Rep MismatchMsg x)
    -> (forall x. Rep MismatchMsg x -> MismatchMsg)
    -> Generic MismatchMsg
    forall x. Rep MismatchMsg x -> MismatchMsg
    forall x. MismatchMsg -> Rep MismatchMsg x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. MismatchMsg -> Rep MismatchMsg x
    from :: forall x. MismatchMsg -> Rep MismatchMsg x
    $cto :: forall x. Rep MismatchMsg x -> MismatchMsg
    to :: forall x. Rep MismatchMsg x -> MismatchMsg
    Generic

    -- | Construct a basic mismatch message between two types.
    --
    -- See 'pprMismatchMsg' for how such a message is displayed to users.
    mkBasicMismatchMsg :: MismatchEA -> ErrorItem -> Type -> Type -> MismatchMsg
    mkBasicMismatchMsg :: MismatchEA -> ErrorItem -> Type -> Type -> MismatchMsg
    mkBasicMismatchMsg MismatchEA
    ea ErrorItem
    item Type
    ty1 Type
    ty2
      = BasicMismatch
          { mismatch_ea :: MismatchEA
    mismatch_ea           = MismatchEA
    ea
          , mismatch_item :: ErrorItem
    mismatch_item         = ErrorItem
    item
          , mismatch_ty1 :: Type
    mismatch_ty1          = Type
    ty1
          , mismatch_ty2 :: Type
    mismatch_ty2          = Type
    ty2
          , mismatch_whenMatching :: Maybe WhenMatching
    mismatch_whenMatching = Maybe WhenMatching
    forall a. Maybe a
    Nothing
          , mismatch_mb_same_occ :: Maybe SameOccInfo
    mismatch_mb_same_occ  = Maybe SameOccInfo
    forall a. Maybe a
    Nothing
          }

    -- | Whether to use expected/actual in a type mismatch message.
    data MismatchEA
      -- | Don't use expected/actual.
      = NoEA
      -- | Use expected/actual.
      | EA
      { MismatchEA -> Maybe ExpectedActualInfo
    mismatch_mbEA :: Maybe ExpectedActualInfo
        -- ^ Whether to also mention type synonym expansion.
      }

    data CannotUnifyVariableReason
      =  -- | A type equality between a type variable and a polytype.
        --
        -- Test cases: T12427a, T2846b, T10194, ...
        CannotUnifyWithPolytype ErrorItem TyVar Type (Maybe TyVarInfo)

      -- | An occurs check.
      | OccursCheck
        { CannotUnifyVariableReason -> [TcTyVar]
    occursCheckInterestingTyVars :: [TyVar]
        , CannotUnifyVariableReason -> [AmbiguityInfo]
    occursCheckAmbiguityInfos    :: [AmbiguityInfo] }

      -- | A skolem type variable escapes its scope.
      --
      -- Example:
      --
      --   data Ex where { MkEx :: a -> MkEx }
      --   foo (MkEx x) = x
      --
      -- Test cases: TypeSkolEscape, T11142.
      | SkolemEscape ErrorItem Implication [TyVar]

      -- | Can't unify the type variable with the other type
      -- due to the kind of type variable it is.
      --
      -- For example, trying to unify a 'SkolemTv' with the
      -- type Int, or with a 'TyVarTv'.
      | DifferentTyVars TyVarInfo
      | RepresentationalEq TyVarInfo (Maybe CoercibleMsg)
      deriving (forall x.
     CannotUnifyVariableReason -> Rep CannotUnifyVariableReason x)
    -> (forall x.
        Rep CannotUnifyVariableReason x -> CannotUnifyVariableReason)
    -> Generic CannotUnifyVariableReason
    forall x.
    Rep CannotUnifyVariableReason x -> CannotUnifyVariableReason
    forall x.
    CannotUnifyVariableReason -> Rep CannotUnifyVariableReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x.
    CannotUnifyVariableReason -> Rep CannotUnifyVariableReason x
    from :: forall x.
    CannotUnifyVariableReason -> Rep CannotUnifyVariableReason x
    $cto :: forall x.
    Rep CannotUnifyVariableReason x -> CannotUnifyVariableReason
    to :: forall x.
    Rep CannotUnifyVariableReason x -> CannotUnifyVariableReason
    Generic

    -- | Report a mismatch error without any extra
    -- information.
    mkPlainMismatchMsg :: MismatchMsg -> TcSolverReportMsg
    mkPlainMismatchMsg :: MismatchMsg -> TcSolverReportMsg
    mkPlainMismatchMsg MismatchMsg
    msg
      = Mismatch
         { mismatchMsg :: MismatchMsg
    mismatchMsg           = MismatchMsg
    msg
         , mismatchTyVarInfo :: Maybe TyVarInfo
    mismatchTyVarInfo     = Maybe TyVarInfo
    forall a. Maybe a
    Nothing
         , mismatchAmbiguityInfo :: [AmbiguityInfo]
    mismatchAmbiguityInfo = []
         , mismatchCoercibleInfo :: Maybe CoercibleMsg
    mismatchCoercibleInfo = Maybe CoercibleMsg
    forall a. Maybe a
    Nothing }

    -- | Additional information to be given in a 'CouldNotDeduce' message,
    -- which is then passed on to 'mk_supplementary_ea_msg'.
    data CND_Extra = CND_Extra TypeOrKind Type Type

    -- | A cue to print out information about type variables,
    -- e.g. where they were bound, when there is a mismatch @tv1 ~ ty2@.
    data TyVarInfo =
      TyVarInfo { TyVarInfo -> TcTyVar
    thisTyVar :: TyVar
                , TyVarInfo -> Maybe Implication
    thisTyVarIsUntouchable :: Maybe Implication
                , TyVarInfo -> Maybe TcTyVar
    otherTy   :: Maybe TyVar }

    -- | Add some information to disambiguate errors in which
    -- two 'Names' would otherwise appear to be identical.
    --
    -- See Note [Disambiguating (X ~ X) errors].
    data SameOccInfo
      = SameOcc
        { SameOccInfo -> Bool
    sameOcc_same_pkg :: Bool -- ^ Whether the two 'Name's also came from the same package.
        , SameOccInfo -> Name
    sameOcc_lhs :: Name
        , SameOccInfo -> Name
    sameOcc_rhs :: Name }

    -- | Add some information about ambiguity
    data AmbiguityInfo

      -- | Some type variables remained ambiguous: print them to the user.
      = Ambiguity
        { AmbiguityInfo -> Bool
    lead_with_ambig_msg :: Bool -- ^ True <=> start the message with "Ambiguous type variable ..."
                                      --  False <=> create a message of the form "The type variable is ambiguous."
        , AmbiguityInfo -> ([TcTyVar], [TcTyVar])
    ambig_tyvars        :: ([TyVar], [TyVar]) -- ^ Ambiguous kind and type variables, respectively.
                                                    -- Guaranteed to not both be empty.
        }

      -- | Remind the user that a particular type family is not injective.
      | NonInjectiveTyFam TyCon

    -- | Expected/actual information.
    data ExpectedActualInfo
      -- | Display the expected and actual types.
      = ExpectedActual
         { ExpectedActualInfo -> Type
    ea_expected, ExpectedActualInfo -> Type
    ea_actual :: Type }

      -- | Display the expected and actual types, after expanding type synonyms.
      | ExpectedActualAfterTySynExpansion
         { ExpectedActualInfo -> Type
    ea_expanded_expected, ExpectedActualInfo -> Type
    ea_expanded_actual :: Type }

    -- | Explain how a kind equality originated.
    data WhenMatching

      = WhenMatching TcType TcType CtOrigin (Maybe TypeOrKind)
      deriving (forall x. WhenMatching -> Rep WhenMatching x)
    -> (forall x. Rep WhenMatching x -> WhenMatching)
    -> Generic WhenMatching
    forall x. Rep WhenMatching x -> WhenMatching
    forall x. WhenMatching -> Rep WhenMatching x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. WhenMatching -> Rep WhenMatching x
    from :: forall x. WhenMatching -> Rep WhenMatching x
    $cto :: forall x. Rep WhenMatching x -> WhenMatching
    to :: forall x. Rep WhenMatching x -> WhenMatching
    Generic

    data BadImportKind
      -- | Module does not export...
      = BadImportNotExported [GhcHint] -- ^ suggestions for what might have been meant
      -- | Missing @type@ keyword when importing a type.
      -- e.g.  `import TypeLits( (+) )`, where TypeLits exports a /type/ (+), not a /term/ (+)
      -- Then we want to suggest using `import TypeLits( type (+) )`
      | BadImportAvailTyCon Bool -- ^ is ExplicitNamespaces enabled?
      -- | Trying to import a data constructor directly, e.g.
      -- @import Data.Maybe (Just)@ instead of @import Data.Maybe (Maybe(Just))@
      | BadImportAvailDataCon OccName
      -- | The parent does not export the given children.
      | BadImportNotExportedSubordinates [OccName]
      -- | Incorrect @type@ keyword when importing something which isn't a type.
      | BadImportAvailVar
      deriving (forall x. BadImportKind -> Rep BadImportKind x)
    -> (forall x. Rep BadImportKind x -> BadImportKind)
    -> Generic BadImportKind
    forall x. Rep BadImportKind x -> BadImportKind
    forall x. BadImportKind -> Rep BadImportKind x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. BadImportKind -> Rep BadImportKind x
    from :: forall x. BadImportKind -> Rep BadImportKind x
    $cto :: forall x. Rep BadImportKind x -> BadImportKind
    to :: forall x. Rep BadImportKind x -> BadImportKind
    Generic

    -- | Some form of @"not in scope"@ error. See also the 'OutOfScopeHole'
    -- constructor of 'HoleError'.
    data NotInScopeError

      -- | A run-of-the-mill @"not in scope"@ error.
      = NotInScope

      -- | Like 'NotInScope', but when we know we are looking for a
      -- record field.
      | NotARecordField

      -- | An exact 'Name' was not in scope.
      --
      -- This usually indicates a problem with a Template Haskell splice.
      --
      -- Test cases: T5971, T18263.
      | NoExactName Name

      -- The same exact 'Name' occurs in multiple name-spaces.
      --
      -- This usually indicates a problem with a Template Haskell splice.
      --
      -- Test case: T7241.
      | SameName [GlobalRdrElt] -- ^ always at least 2 elements

      -- A type signature, fixity declaration, pragma, standalone kind signature...
      -- is missing an associated binding.
      | MissingBinding SDoc [GhcHint]
        -- TODO: remove the SDoc argument.

      -- | Couldn't find a top-level binding.
      --
      -- Happens when specifying an annotation for something that
      -- is not in scope.
      --
      -- Test cases: annfail01, annfail02, annfail11.
      | NoTopLevelBinding

      -- | A class doesn't have a method with this name,
      -- or, a class doesn't have an associated type with this name,
      -- or, a record doesn't have a record field with this name.
      | UnknownSubordinate SDoc

      -- | A name is not in scope during type checking but passed the renamer.
      --
      -- Test cases:
      --   none
      | NotInScopeTc (NameEnv TcTyThing)
      deriving (forall x. NotInScopeError -> Rep NotInScopeError x)
    -> (forall x. Rep NotInScopeError x -> NotInScopeError)
    -> Generic NotInScopeError
    forall x. Rep NotInScopeError x -> NotInScopeError
    forall x. NotInScopeError -> Rep NotInScopeError x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. NotInScopeError -> Rep NotInScopeError x
    from :: forall x. NotInScopeError -> Rep NotInScopeError x
    $cto :: forall x. Rep NotInScopeError x -> NotInScopeError
    to :: forall x. Rep NotInScopeError x -> NotInScopeError
    Generic

    -- | Create a @"not in scope"@ error message for the given 'RdrName'.
    mkTcRnNotInScope :: RdrName -> NotInScopeError -> TcRnMessage
    mkTcRnNotInScope :: RdrName -> NotInScopeError -> TcRnMessage
    mkTcRnNotInScope RdrName
    rdr NotInScopeError
    err = NotInScopeError
    -> RdrName -> [ImportError] -> [GhcHint] -> TcRnMessage
    TcRnNotInScope NotInScopeError
    err RdrName
    rdr [] [GhcHint]
    noHints

    -- | Configuration for pretty-printing valid hole fits.
    data HoleFitDispConfig =
      HFDC { HoleFitDispConfig -> Bool
    showWrap, HoleFitDispConfig -> Bool
    showWrapVars, HoleFitDispConfig -> Bool
    showType, HoleFitDispConfig -> Bool
    showProv, HoleFitDispConfig -> Bool
    showMatches
              :: Bool }

    -- | Report an error involving a 'Hole'.
    --
    -- This could be an out of scope data constructor or variable,
    -- a typed hole, or a wildcard in a type.
    data HoleError
      -- | Report an out-of-scope data constructor or variable
      -- masquerading as an expression hole.
      --
      -- See Note [Insoluble holes] in GHC.Tc.Types.Constraint.
      -- See 'NotInScopeError' for other not-in-scope errors.
      --
      -- Test cases: T9177a.
      = OutOfScopeHole [ImportError] [GhcHint]
      -- | Report a typed hole, or wildcard, with additional information.
      | HoleError HoleSort
                  [TcTyVar]                     -- Other type variables which get computed on the way.
                  [(SkolemInfoAnon, [TcTyVar])] -- Zonked and grouped skolems for the type of the hole.

    -- | A message that aims to explain why two types couldn't be seen
    -- to be representationally equal.
    data CoercibleMsg
      -- | Not knowing the role of a type constructor prevents us from
      -- concluding that two types are representationally equal.
      --
      -- Example:
      --
      --   foo :: Applicative m => m (Sum Int)
      --   foo = coerce (pure $ 1 :: Int)
      --
      -- We don't know what role `m` has, so we can't coerce `m Int` to `m (Sum Int)`.
      --
      -- Test cases: T8984, TcCoercibleFail.
      = UnknownRoles Type

      -- | The fact that a 'TyCon' is abstract prevents us from decomposing
      -- a 'TyConApp' and deducing that two types are representationally equal.
      --
      -- Test cases: none.
      | TyConIsAbstract TyCon

      -- | We can't unwrap a newtype whose constructor is not in scope.
      --
      -- Example:
      --
      --   import Data.Ord (Down) -- NB: not importing the constructor
      --   foo :: Int -> Down Int
      --   foo = coerce
      --
      -- Test cases: TcCoercibleFail.
      | OutOfScopeNewtypeConstructor TyCon DataCon

    -- | Explain a problem with an import.
    data ImportError
      -- | Couldn't find a module with the requested name.
      = MissingModule ModuleName
      -- | The imported modules don't export what we're looking for.
      | ModulesDoNotExport (NE.NonEmpty Module) OccName

    -- | This datatype collates instances that match or unifier,
    -- in order to report an error message for an unsolved typeclass constraint.
    data PotentialInstances
      = PotentialInstances
      { PotentialInstances -> [ClsInst]
    matches  :: [ClsInst]
      , PotentialInstances -> [ClsInst]
    unifiers :: [ClsInst]
      }

    -- | A collection of valid hole fits or refinement fits,
    -- in which some fits might have been suppressed.
    data FitsMbSuppressed
      = Fits
        { FitsMbSuppressed -> [HoleFit]
    fits           :: [HoleFit]
        , FitsMbSuppressed -> Bool
    fitsSuppressed :: Bool  -- ^ Whether we have suppressed any fits because there were too many.
        }

    -- | A collection of hole fits and refinement fits.
    data ValidHoleFits
      = ValidHoleFits
        { ValidHoleFits -> FitsMbSuppressed
    holeFits       :: FitsMbSuppressed
        , ValidHoleFits -> FitsMbSuppressed
    refinementFits :: FitsMbSuppressed
        }

    noValidHoleFits :: ValidHoleFits
    noValidHoleFits :: ValidHoleFits
    noValidHoleFits = FitsMbSuppressed -> FitsMbSuppressed -> ValidHoleFits
    ValidHoleFits ([HoleFit] -> Bool -> FitsMbSuppressed
    Fits [] Bool
    False) ([HoleFit] -> Bool -> FitsMbSuppressed
    Fits [] Bool
    False)

    data RelevantBindings
      = RelevantBindings
        { RelevantBindings -> [(Name, Type)]
    relevantBindingNamesAndTys :: [(Name, Type)]
        , RelevantBindings -> Bool
    ranOutOfFuel               :: Bool -- ^ Whether we ran out of fuel generating the bindings.
        }

    -- | Display some relevant bindings.
    pprRelevantBindings :: RelevantBindings -> SDoc
    -- This function should be in "GHC.Tc.Errors.Ppr",
    -- but it's here for the moment as it's needed in "GHC.Tc.Errors".
    pprRelevantBindings :: RelevantBindings -> SDoc
    pprRelevantBindings (RelevantBindings [(Name, Type)]
    bds Bool
    ran_out_of_fuel) =
      Bool -> SDoc -> SDoc
    forall doc. IsOutput doc => Bool -> doc -> doc
    ppUnless ([(Name, Type)] -> Bool
    forall a. [a] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null [(Name, Type)]
    rel_bds) (SDoc -> SDoc) -> SDoc -> SDoc
    forall a b. (a -> b) -> a -> b
    $
        SDoc -> Int -> SDoc -> SDoc
    hang (String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "Relevant bindings include")
           Int
    2 ([SDoc] -> SDoc
    forall doc. IsDoc doc => [doc] -> doc
    vcat (((Name, Type) -> SDoc) -> [(Name, Type)] -> [SDoc]
    forall a b. (a -> b) -> [a] -> [b]
    map (Name, Type) -> SDoc
    forall {a} {a}.
    (OutputableBndr a, NamedThing a, Outputable a) =>
    (a, a) -> SDoc
    ppr_binding [(Name, Type)]
    rel_bds) SDoc -> SDoc -> SDoc
    forall doc. IsDoc doc => doc -> doc -> doc
    $$ Bool -> SDoc -> SDoc
    forall doc. IsOutput doc => Bool -> doc -> doc
    ppWhen Bool
    ran_out_of_fuel SDoc
    discardMsg)
      where
        ppr_binding :: (a, a) -> SDoc
    ppr_binding (a
    nm, a
    tidy_ty) =
          [SDoc] -> SDoc
    forall doc. IsLine doc => [doc] -> doc
    sep [ a -> SDoc
    forall a. OutputableBndr a => a -> SDoc
    pprPrefixOcc a
    nm SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> SDoc
    dcolon SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> a -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr a
    tidy_ty
              , Int -> SDoc -> SDoc
    nest Int
    2 (SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc
    parens (String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "bound at"
                   SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+> SrcLoc -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr (a -> SrcLoc
    forall a. NamedThing a => a -> SrcLoc
    getSrcLoc a
    nm)))]
        rel_bds :: [(Name, Type)]
    rel_bds = ((Name, Type) -> Bool) -> [(Name, Type)] -> [(Name, Type)]
    forall a. (a -> Bool) -> [a] -> [a]
    filter (Bool -> Bool
    not (Bool -> Bool) -> ((Name, Type) -> Bool) -> (Name, Type) -> Bool
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . SrcSpan -> Bool
    isGeneratedSrcSpan (SrcSpan -> Bool)
    -> ((Name, Type) -> SrcSpan) -> (Name, Type) -> Bool
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Name -> SrcSpan
    forall a. NamedThing a => a -> SrcSpan
    getSrcSpan (Name -> SrcSpan)
    -> ((Name, Type) -> Name) -> (Name, Type) -> SrcSpan
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . (Name, Type) -> Name
    forall a b. (a, b) -> a
    fst) [(Name, Type)]
    bds

    discardMsg :: SDoc
    discardMsg :: SDoc
    discardMsg = String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "(Some bindings suppressed;" SDoc -> SDoc -> SDoc
    forall doc. IsLine doc => doc -> doc -> doc
    <+>
                 String -> SDoc
    forall doc. IsLine doc => String -> doc
    text String
    "use -fmax-relevant-binds=N or -fno-max-relevant-binds)"

    -- | Stores the information to be reported in a representation-polymorphism
    -- error message.
    data FixedRuntimeRepErrorInfo
      = FRR_Info
      { FixedRuntimeRepErrorInfo -> FixedRuntimeRepOrigin
    frr_info_origin       :: FixedRuntimeRepOrigin
          -- ^ What is the original type we checked for
          -- representation-polymorphism, and what specific
          -- check did we perform?
      , FixedRuntimeRepErrorInfo -> Maybe (TcTyVar, Type)
    frr_info_not_concrete :: Maybe (TcTyVar, TcType)
          -- ^ Which non-concrete type did we try to
          -- unify this concrete type variable with?
      }

    {-
    ************************************************************************
    *                                                                      *
    \subsection{Contexts for renaming errors}
    *                                                                      *
    ************************************************************************
    -}

    -- AZ:TODO: Change these all to be Name instead of RdrName.
    --          Merge TcType.UserTypeContext in to it.
    data HsDocContext
      = TypeSigCtx SDoc
      | StandaloneKindSigCtx SDoc
      | PatCtx
      | SpecInstSigCtx
      | DefaultDeclCtx
      | ForeignDeclCtx (LocatedN RdrName)
      | DerivDeclCtx
      | RuleCtx FastString
      | TyDataCtx (LocatedN RdrName)
      | TySynCtx (LocatedN RdrName)
      | TyFamilyCtx (LocatedN RdrName)
      | FamPatCtx (LocatedN RdrName)    -- The patterns of a type/data family instance
      | ConDeclCtx [LocatedN Name]
      | ClassDeclCtx (LocatedN RdrName)
      | ExprWithTySigCtx
      | TypBrCtx
      | HsTypeCtx
      | HsTypePatCtx
      | GHCiCtx
      | SpliceTypeCtx (LHsType GhcPs)
      | ClassInstanceCtx
      | GenericCtx SDoc

    -- | Context for a mismatch in the number of arguments
    data MatchArgsContext
      = EquationArgs
          !Name -- ^ Name of the function
      | PatternArgs
          !HsMatchContextRn -- ^ Pattern match specifics

    -- | The information necessary to report mismatched
    -- numbers of arguments in a match group.
    data MatchArgBadMatches where
      MatchArgMatches
        ::  { ()
    matchArgFirstMatch :: LocatedA (Match GhcRn body)
            , ()
    matchArgBadMatches :: NE.NonEmpty (LocatedA (Match GhcRn body)) }
        -> MatchArgBadMatches

    data PragmaWarningInfo
      = PragmaWarningName { PragmaWarningInfo -> OccName
    pwarn_occname :: OccName
                          , PragmaWarningInfo -> ModuleName
    pwarn_impmod :: ModuleName
                          , PragmaWarningInfo -> ModuleName
    pwarn_declmod :: ModuleName }
      | PragmaWarningExport { pwarn_occname :: OccName
                            , pwarn_impmod :: ModuleName }
      | PragmaWarningInstance { PragmaWarningInfo -> TcTyVar
    pwarn_dfunid :: DFunId
                              , PragmaWarningInfo -> CtOrigin
    pwarn_ctorig :: CtOrigin }

    -- | The context for an "empty statement group" error.
    data EmptyStatementGroupErrReason
      = EmptyStmtsGroupInParallelComp
      -- ^ Empty statement group in a parallel list comprehension
      | EmptyStmtsGroupInTransformListComp
      -- ^ Empty statement group in a transform list comprehension
      --
      --   Example:
      --   [() | then ()]
      | EmptyStmtsGroupInDoNotation HsDoFlavour
      -- ^ Empty statement group in do notation
      --
      --   Example:
      --   do
      | EmptyStmtsGroupInArrowNotation
      -- ^ Empty statement group in arrow notation
      --
      --   Example:
      --   proc () -> do

      deriving ((forall x.
     EmptyStatementGroupErrReason -> Rep EmptyStatementGroupErrReason x)
    -> (forall x.
        Rep EmptyStatementGroupErrReason x -> EmptyStatementGroupErrReason)
    -> Generic EmptyStatementGroupErrReason
    forall x.
    Rep EmptyStatementGroupErrReason x -> EmptyStatementGroupErrReason
    forall x.
    EmptyStatementGroupErrReason -> Rep EmptyStatementGroupErrReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x.
    EmptyStatementGroupErrReason -> Rep EmptyStatementGroupErrReason x
    from :: forall x.
    EmptyStatementGroupErrReason -> Rep EmptyStatementGroupErrReason x
    $cto :: forall x.
    Rep EmptyStatementGroupErrReason x -> EmptyStatementGroupErrReason
    to :: forall x.
    Rep EmptyStatementGroupErrReason x -> EmptyStatementGroupErrReason
    Generic)

    -- | An existential wrapper around @'StmtLR' GhcPs GhcPs body@.
    data UnexpectedStatement where
      UnexpectedStatement
        :: 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

    data RuleLhsErrReason
      = UnboundVariable RdrName NotInScopeError
      | IllegalExpression

    data HsigShapeMismatchReason =
      {-| HsigShapeSortMismatch is an error indicating that an item in the
        export list of a signature doesn't match the item of the same name in
        another signature when merging the two – one is a type while the other is a
        plain identifier.

        Test cases:
          none
      -}
      HsigShapeSortMismatch !AvailInfo !AvailInfo
      |
      {-| HsigShapeNotUnifiable is an error indicating that a name in the
        export list of a signature cannot be unified with a name of the same name in
        another signature when merging the two.

        Test cases:
          bkpfail20, bkpfail21
      -}
      HsigShapeNotUnifiable !Name !Name !Bool
      deriving ((forall x.
     HsigShapeMismatchReason -> Rep HsigShapeMismatchReason x)
    -> (forall x.
        Rep HsigShapeMismatchReason x -> HsigShapeMismatchReason)
    -> Generic HsigShapeMismatchReason
    forall x. Rep HsigShapeMismatchReason x -> HsigShapeMismatchReason
    forall x. HsigShapeMismatchReason -> Rep HsigShapeMismatchReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. HsigShapeMismatchReason -> Rep HsigShapeMismatchReason x
    from :: forall x. HsigShapeMismatchReason -> Rep HsigShapeMismatchReason x
    $cto :: forall x. Rep HsigShapeMismatchReason x -> HsigShapeMismatchReason
    to :: forall x. Rep HsigShapeMismatchReason x -> HsigShapeMismatchReason
    Generic)

    data WrongThingSort
      = WrongThingType
      | WrongThingDataCon
      | WrongThingPatSyn
      | WrongThingConLike
      | WrongThingClass
      | WrongThingTyCon
      | WrongThingAxiom

    data StageCheckReason
      = StageCheckInstance !InstanceWhat !PredType
      | StageCheckSplice !Name

    data UninferrableTyVarCtx
      = UninfTyCtx_ClassContext [TcType]
      | UninfTyCtx_DataContext [TcType]
      | UninfTyCtx_ProvidedContext [TcType]
      | UninfTyCtx_TyFamRhs TcType
      | UninfTyCtx_TySynRhs TcType
      | UninfTyCtx_Sig TcType (LHsSigType GhcRn)

    data PatSynInvalidRhsReason
      = PatSynNotInvertible !(Pat GhcRn)
      | PatSynUnboundVar !Name
      deriving ((forall x. PatSynInvalidRhsReason -> Rep PatSynInvalidRhsReason x)
    -> (forall x.
        Rep PatSynInvalidRhsReason x -> PatSynInvalidRhsReason)
    -> Generic PatSynInvalidRhsReason
    forall x. Rep PatSynInvalidRhsReason x -> PatSynInvalidRhsReason
    forall x. PatSynInvalidRhsReason -> Rep PatSynInvalidRhsReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. PatSynInvalidRhsReason -> Rep PatSynInvalidRhsReason x
    from :: forall x. PatSynInvalidRhsReason -> Rep PatSynInvalidRhsReason x
    $cto :: forall x. Rep PatSynInvalidRhsReason x -> PatSynInvalidRhsReason
    to :: forall x. Rep PatSynInvalidRhsReason x -> PatSynInvalidRhsReason
    Generic)

    data BadFieldAnnotationReason where
      {-| A lazy data type field annotation (~) was used without enabling the
        extension StrictData.

        Test cases:
        LazyFieldsDisabled
      -}
      LazyFieldsDisabled :: BadFieldAnnotationReason
      {-| An UNPACK pragma was applied to a field without strictness annotation (!).

        Test cases:
        T14761a, T7562
      -}
      UnpackWithoutStrictness :: BadFieldAnnotationReason
      {-| An UNPACK pragma was applied to an abstract type in an indefinite package
        in Backpack.

        Test cases:
        unpack_sums_5, T3966, T7050
      -}
      BackpackUnpackAbstractType :: BadFieldAnnotationReason
      deriving ((forall x.
     BadFieldAnnotationReason -> Rep BadFieldAnnotationReason x)
    -> (forall x.
        Rep BadFieldAnnotationReason x -> BadFieldAnnotationReason)
    -> Generic BadFieldAnnotationReason
    forall x.
    Rep BadFieldAnnotationReason x -> BadFieldAnnotationReason
    forall x.
    BadFieldAnnotationReason -> Rep BadFieldAnnotationReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x.
    BadFieldAnnotationReason -> Rep BadFieldAnnotationReason x
    from :: forall x.
    BadFieldAnnotationReason -> Rep BadFieldAnnotationReason x
    $cto :: forall x.
    Rep BadFieldAnnotationReason x -> BadFieldAnnotationReason
    to :: forall x.
    Rep BadFieldAnnotationReason x -> BadFieldAnnotationReason
    Generic)

    data SuperclassCycle =
      MkSuperclassCycle { SuperclassCycle -> Class
    cls :: Class, SuperclassCycle -> Bool
    definite :: Bool, SuperclassCycle -> [SuperclassCycleDetail]
    reasons :: [SuperclassCycleDetail] }

    data SuperclassCycleDetail
      = SCD_HeadTyVar !PredType
      | SCD_HeadTyFam !PredType
      | SCD_Superclass !Class

    data RoleValidationFailedReason
      = TyVarRoleMismatch !TyVar !Role
      | TyVarMissingInEnv !TyVar
      | BadCoercionRole !Coercion
      deriving ((forall x.
     RoleValidationFailedReason -> Rep RoleValidationFailedReason x)
    -> (forall x.
        Rep RoleValidationFailedReason x -> RoleValidationFailedReason)
    -> Generic RoleValidationFailedReason
    forall x.
    Rep RoleValidationFailedReason x -> RoleValidationFailedReason
    forall x.
    RoleValidationFailedReason -> Rep RoleValidationFailedReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x.
    RoleValidationFailedReason -> Rep RoleValidationFailedReason x
    from :: forall x.
    RoleValidationFailedReason -> Rep RoleValidationFailedReason x
    $cto :: forall x.
    Rep RoleValidationFailedReason x -> RoleValidationFailedReason
    to :: forall x.
    Rep RoleValidationFailedReason x -> RoleValidationFailedReason
    Generic)

    data DisabledClassExtension where
      {-| MultiParamTypeClasses is required.

        Test cases:
        readFail037, TcNoNullaryTC
      -}
      MultiParamDisabled :: !Int -- ^ The arity
                         -> DisabledClassExtension
      {-| FunctionalDependencies is required.

        Test cases:
        readFail041
      -}
      FunDepsDisabled :: DisabledClassExtension
      {-| ConstrainedClassMethods is required.

        Test cases:
        mod39, tcfail150
      -}
      ConstrainedClassMethodsDisabled :: !Id
                                      -> !TcPredType
                                      -> DisabledClassExtension
      deriving ((forall x. DisabledClassExtension -> Rep DisabledClassExtension x)
    -> (forall x.
        Rep DisabledClassExtension x -> DisabledClassExtension)
    -> Generic DisabledClassExtension
    forall x. Rep DisabledClassExtension x -> DisabledClassExtension
    forall x. DisabledClassExtension -> Rep DisabledClassExtension x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. DisabledClassExtension -> Rep DisabledClassExtension x
    from :: forall x. DisabledClassExtension -> Rep DisabledClassExtension x
    $cto :: forall x. Rep DisabledClassExtension x -> DisabledClassExtension
    to :: forall x. Rep DisabledClassExtension x -> DisabledClassExtension
    Generic)

    data TyFamsDisabledReason
      = TyFamsDisabledFamily !Name
      | TyFamsDisabledInstance !TyCon
      deriving ((forall x. TyFamsDisabledReason -> Rep TyFamsDisabledReason x)
    -> (forall x. Rep TyFamsDisabledReason x -> TyFamsDisabledReason)
    -> Generic TyFamsDisabledReason
    forall x. Rep TyFamsDisabledReason x -> TyFamsDisabledReason
    forall x. TyFamsDisabledReason -> Rep TyFamsDisabledReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. TyFamsDisabledReason -> Rep TyFamsDisabledReason x
    from :: forall x. TyFamsDisabledReason -> Rep TyFamsDisabledReason x
    $cto :: forall x. Rep TyFamsDisabledReason x -> TyFamsDisabledReason
    to :: forall x. Rep TyFamsDisabledReason x -> TyFamsDisabledReason
    Generic)

    data TypeApplication
      = TypeApplication !(HsType GhcPs) !TypeOrKind
      | TypeApplicationInPattern !(HsConPatTyArg GhcPs)
      deriving (forall x. TypeApplication -> Rep TypeApplication x)
    -> (forall x. Rep TypeApplication x -> TypeApplication)
    -> Generic TypeApplication
    forall x. Rep TypeApplication x -> TypeApplication
    forall x. TypeApplication -> Rep TypeApplication x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. TypeApplication -> Rep TypeApplication x
    from :: forall x. TypeApplication -> Rep TypeApplication x
    $cto :: forall x. Rep TypeApplication x -> TypeApplication
    to :: forall x. Rep TypeApplication x -> TypeApplication
    Generic

    -- | Why was the empty case rejected?
    data BadEmptyCaseReason
      = EmptyCaseWithoutFlag
      | EmptyCaseDisallowedCtxt
      | EmptyCaseForall ForAllTyBinder

    -- | Either `HsType p` or `HsSigType p`.
    --
    -- Used for reporting errors in `TcRnIllegalKind`.
    data HsTypeOrSigType p
      = HsType    (HsType p)
      | HsSigType (HsSigType p)

    instance OutputableBndrId p => Outputable (HsTypeOrSigType (GhcPass p)) where
      ppr :: HsTypeOrSigType (GhcPass p) -> SDoc
    ppr (HsType HsType (GhcPass p)
    ty) = HsType (GhcPass p) -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr HsType (GhcPass p)
    ty
      ppr (HsSigType HsSigType (GhcPass p)
    sig_ty) = HsSigType (GhcPass p) -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr HsSigType (GhcPass p)
    sig_ty

    -- | A wrapper around HsTyVarBndr.
    -- Used for reporting errors in `TcRnUnusedQuantifiedTypeVar`.
    data HsTyVarBndrExistentialFlag = forall flag. OutputableBndrFlag flag 'Renamed =>
      HsTyVarBndrExistentialFlag (HsTyVarBndr flag GhcRn)

    instance Outputable HsTyVarBndrExistentialFlag where
      ppr :: HsTyVarBndrExistentialFlag -> SDoc
    ppr (HsTyVarBndrExistentialFlag HsTyVarBndr flag GhcRn
    hsTyVarBndr) = HsTyVarBndr flag GhcRn -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr HsTyVarBndr flag GhcRn
    hsTyVarBndr

    type TySynCycleTyCons =
      [Either TyCon (LTyClDecl GhcRn)]

    -- | Different types of warnings for dodgy imports.
    data DodgyImportsReason =
      {-| An import of the form 'T(..)' or 'f(..)' does not actually import anything beside
          'T'/'f' itself.

        Test cases:
          DodgyImports
      -}
      DodgyImportsEmptyParent !GlobalRdrElt
      |
      {-| A 'hiding' clause contains something that would be reported as an error in a
        regular import, but is relaxed to a warning.

        Test cases:
          DodgyImports_hiding
      -}
      DodgyImportsHiding !ImportLookupReason
      deriving ((forall x. DodgyImportsReason -> Rep DodgyImportsReason x)
    -> (forall x. Rep DodgyImportsReason x -> DodgyImportsReason)
    -> Generic DodgyImportsReason
    forall x. Rep DodgyImportsReason x -> DodgyImportsReason
    forall x. DodgyImportsReason -> Rep DodgyImportsReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. DodgyImportsReason -> Rep DodgyImportsReason x
    from :: forall x. DodgyImportsReason -> Rep DodgyImportsReason x
    $cto :: forall x. Rep DodgyImportsReason x -> DodgyImportsReason
    to :: forall x. Rep DodgyImportsReason x -> DodgyImportsReason
    Generic)

    -- | Different types of errors for import lookup.
    data ImportLookupReason where
      {-| An item in an import statement is not exported by the corresponding
        module.

        Test cases:
          T21826, recomp001, retc001, mod79, mod80, mod81, mod91, T6007, T7167,
          T9006, T11071, T9905fail2, T5385, T10668
      -}
      ImportLookupBad :: BadImportKind
                      -> ModIface
                      -> ImpDeclSpec
                      -> IE GhcPs
                      -> Bool -- ^ whether @-XPatternSynonyms@ was enabled
                      -> ImportLookupReason
      {-| A name is specified with a qualifying module.

        Test cases:
          T3792
      -}
      ImportLookupQualified :: !RdrName -- ^ The name extracted from the import item
                            -> ImportLookupReason

      {-| Something completely unexpected is in an import list, like @module Foo@.

        Test cases:
          ImportLookupIllegal
      -}
      ImportLookupIllegal :: ImportLookupReason
      {-| An item in an import list matches multiple names exported from that module.

        Test cases:
          None
      -}
      ImportLookupAmbiguous :: !RdrName -- ^ The name extracted from the import item
                            -> ![GlobalRdrElt] -- ^ The potential matches
                            -> ImportLookupReason
      deriving ((forall x. ImportLookupReason -> Rep ImportLookupReason x)
    -> (forall x. Rep ImportLookupReason x -> ImportLookupReason)
    -> Generic ImportLookupReason
    forall x. Rep ImportLookupReason x -> ImportLookupReason
    forall x. ImportLookupReason -> Rep ImportLookupReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. ImportLookupReason -> Rep ImportLookupReason x
    from :: forall x. ImportLookupReason -> Rep ImportLookupReason x
    $cto :: forall x. Rep ImportLookupReason x -> ImportLookupReason
    to :: forall x. Rep ImportLookupReason x -> ImportLookupReason
    Generic)

    -- | Distinguish record fields from other names for pretty-printing.
    data UnusedImportName where
      UnusedImportNameRecField :: !Parent -> !OccName -> UnusedImportName
      UnusedImportNameRegular :: !Name -> UnusedImportName

    -- | Different types of errors for unused imports.
    data UnusedImportReason where
      {-| No names in the import list are used in the module.

        Test cases:
          overloadedrecfldsfail06, T10890_2, t22391, t22391j, T1074, prog018,
          mod177, rn046, rn037, T5211
      -}
      UnusedImportNone :: UnusedImportReason
      {-| A set of names in the import list are not used in the module.

        Test cases:
          overloadedrecfldsfail06, T17324, mod176, T11970A, rn046, T14881,
          T7454, T8149, T13064
      -}
      UnusedImportSome :: ![UnusedImportName] -- ^ The unsed names
                       -> UnusedImportReason
      deriving ((forall x. UnusedImportReason -> Rep UnusedImportReason x)
    -> (forall x. Rep UnusedImportReason x -> UnusedImportReason)
    -> Generic UnusedImportReason
    forall x. Rep UnusedImportReason x -> UnusedImportReason
    forall x. UnusedImportReason -> Rep UnusedImportReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. UnusedImportReason -> Rep UnusedImportReason x
    from :: forall x. UnusedImportReason -> Rep UnusedImportReason x
    $cto :: forall x. Rep UnusedImportReason x -> UnusedImportReason
    to :: forall x. Rep UnusedImportReason x -> UnusedImportReason
    Generic)

    -- | Different places in which a nested foralls/contexts error might occur.
    data NestedForallsContextsIn
      -- | Nested forall in @SPECIALISE instance@
      = NFC_Specialize
      -- | Nested forall in @deriving via@ (via-type)
      | NFC_ViaType
      -- | Nested forall in the type of a GADT constructor
      | NFC_GadtConSig
      -- | Nested forall in an instance head
      | NFC_InstanceHead
      -- | Nested forall in a standalone deriving instance head
      | NFC_StandaloneDerivedInstanceHead
      -- | Nested forall in deriving class type
      | NFC_DerivedClassType

    -- | Provenance of an unused name.
    data UnusedNameProv
      = UnusedNameTopDecl
      | UnusedNameImported !ModuleName
      | UnusedNameTypePattern
      | UnusedNameMatch
      | UnusedNameLocalBind

    -- | Different reasons for TcRnNonCanonicalDefinition.
    data NonCanonicalDefinition =
      -- | Related to @(<>)@ and @mappend@.
      NonCanonicalMonoid NonCanonical_Monoid
      |
      -- | Related to @(*>)@/@(>>)@ and @pure@/@return@.
      NonCanonicalMonad NonCanonical_Monad
      deriving ((forall x. NonCanonicalDefinition -> Rep NonCanonicalDefinition x)
    -> (forall x.
        Rep NonCanonicalDefinition x -> NonCanonicalDefinition)
    -> Generic NonCanonicalDefinition
    forall x. Rep NonCanonicalDefinition x -> NonCanonicalDefinition
    forall x. NonCanonicalDefinition -> Rep NonCanonicalDefinition x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. NonCanonicalDefinition -> Rep NonCanonicalDefinition x
    from :: forall x. NonCanonicalDefinition -> Rep NonCanonicalDefinition x
    $cto :: forall x. Rep NonCanonicalDefinition x -> NonCanonicalDefinition
    to :: forall x. Rep NonCanonicalDefinition x -> NonCanonicalDefinition
    Generic)

    -- | Possible cases for the -Wnoncanonical-monoid-instances.
    data NonCanonical_Monoid =
      -- | @(<>) = mappend@ was defined.
      NonCanonical_Sappend
      |
      -- | @mappend@ was defined as something other than @(<>)@.
      NonCanonical_Mappend

    -- | Possible cases for the -Wnoncanonical-monad-instances.
    data NonCanonical_Monad =
      -- | @pure = return@ was defined.
      NonCanonical_Pure
      |
      -- | @(*>) = (>>)@ was defined.
      NonCanonical_ThenA
      |
      -- | @return@ was defined as something other than @pure@.
      NonCanonical_Return
      |
      -- | @(>>)@ was defined as something other than @(*>)@.
      NonCanonical_ThenM

    -- | Why was an instance declaration rejected?
    data IllegalInstanceReason
      = IllegalClassInstance
          !TypedThing -- ^ the instance head type
          !IllegalClassInstanceReason -- ^ the problem with the instance head
      | IllegalFamilyInstance !IllegalFamilyInstanceReason
      | IllegalFamilyApplicationInInstance
          !Type   -- ^ the instance head type
          !Bool   -- ^ is this an invisible argument?
          !TyCon  -- ^ type family
          ![Type] -- ^ type family argument
      deriving (forall x. IllegalInstanceReason -> Rep IllegalInstanceReason x)
    -> (forall x. Rep IllegalInstanceReason x -> IllegalInstanceReason)
    -> Generic IllegalInstanceReason
    forall x. Rep IllegalInstanceReason x -> IllegalInstanceReason
    forall x. IllegalInstanceReason -> Rep IllegalInstanceReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. IllegalInstanceReason -> Rep IllegalInstanceReason x
    from :: forall x. IllegalInstanceReason -> Rep IllegalInstanceReason x
    $cto :: forall x. Rep IllegalInstanceReason x -> IllegalInstanceReason
    to :: forall x. Rep IllegalInstanceReason x -> IllegalInstanceReason
    Generic

    -- | Why was a class instance declaration rejected?
    data IllegalClassInstanceReason
      -- | An illegal type at the head of the instance.
      --
      -- See t'IllegalInstanceHeadReason'.
      = IllegalInstanceHead !IllegalInstanceHeadReason
      -- | An illegal HasField instance. See t'IllegalHasFieldInstance'.
      | IllegalHasFieldInstance !IllegalHasFieldInstance
      -- | An illegal instance for a built-in typeclass such as
      --   'Coercible', 'Typeable', or 'KnownNat', outside of a signature file.
      --
      --   Test cases: deriving/should_fail/T9687
      --               deriving/should_fail/T14916
      --               polykinds/T8132
      --               typecheck/should_fail/TcCoercibleFail2
      --               typecheck/should_fail/T12837
      --               typecheck/should_fail/T14390
      | IllegalSpecialClassInstance !Class !Bool -- ^ Whether the error is due to Safe Haskell being enabled
      -- | The instance failed the coverage condition, i.e. the functional
      -- dependencies were not respected.
      --
      -- Example:
      --
      --  class C a b | a -> b where {..}
      --  instance C a b where {..}
      --
      -- Test cases: T9106, T10570, T2247, T12803, tcfail170.
      | IllegalInstanceFailsCoverageCondition
          !Class !CoverageProblem
      deriving (forall x.
     IllegalClassInstanceReason -> Rep IllegalClassInstanceReason x)
    -> (forall x.
        Rep IllegalClassInstanceReason x -> IllegalClassInstanceReason)
    -> Generic IllegalClassInstanceReason
    forall x.
    Rep IllegalClassInstanceReason x -> IllegalClassInstanceReason
    forall x.
    IllegalClassInstanceReason -> Rep IllegalClassInstanceReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x.
    IllegalClassInstanceReason -> Rep IllegalClassInstanceReason x
    from :: forall x.
    IllegalClassInstanceReason -> Rep IllegalClassInstanceReason x
    $cto :: forall x.
    Rep IllegalClassInstanceReason x -> IllegalClassInstanceReason
    to :: forall x.
    Rep IllegalClassInstanceReason x -> IllegalClassInstanceReason
    Generic

    -- | Why was a HasField instance declaration rejected?
    data IllegalHasFieldInstance
      -- | HasField instance for a type not headed by a TyCon.
      --
      -- Example:
      --
      --   instance HasField a where {..}
      --
      -- Test case: hasfieldfail03
      = IllegalHasFieldInstanceNotATyCon
      -- | HasField instance for a data family.
      --
      -- Example:
      --
      --  data family D a
      --  data instance D Int = MkDInt Char
      --
      --  instance HasField "fld" (D Int) where {..}
      --
      -- Test case: hasfieldfail03
      | IllegalHasFieldInstanceFamilyTyCon
      -- | HasField instance for a type that already has that field.
      --
      -- Example
      --
      --  data T = MkT { quux :: Int }
      --  instance HasField "quux" T Int where {..}
      --
      -- Test case: hasfieldfail03
      | IllegalHasFieldInstanceTyConHasField !TyCon !FieldLabelString
      -- | HasField instance for a type that already has fields, when the
      -- field label could potentially unify with those fields.
      --
      -- Example:
      --
      --  data T = MkInt { quux :: Int }
      --  instance forall (fld :: Symbol). HasField fld T Int where {..}
      --
      -- Test case: hasfieldfail03
      | IllegalHasFieldInstanceTyConHasFields !TyCon !Type -- ^ the label type in the instance head
      deriving (forall x.
     IllegalHasFieldInstance -> Rep IllegalHasFieldInstance x)
    -> (forall x.
        Rep IllegalHasFieldInstance x -> IllegalHasFieldInstance)
    -> Generic IllegalHasFieldInstance
    forall x. Rep IllegalHasFieldInstance x -> IllegalHasFieldInstance
    forall x. IllegalHasFieldInstance -> Rep IllegalHasFieldInstance x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. IllegalHasFieldInstance -> Rep IllegalHasFieldInstance x
    from :: forall x. IllegalHasFieldInstance -> Rep IllegalHasFieldInstance x
    $cto :: forall x. Rep IllegalHasFieldInstance x -> IllegalHasFieldInstance
    to :: forall x. Rep IllegalHasFieldInstance x -> IllegalHasFieldInstance
    Generic

    -- | Description of an instance coverage condition failure.
    data CoverageProblem =
      CoverageProblem
        { CoverageProblem -> ([TcTyVar], [TcTyVar])
    not_covered_fundep        :: ([TyVar], [TyVar])
        , CoverageProblem -> ([Type], [Type])
    not_covered_fundep_inst   :: ([Type], [Type])
        , CoverageProblem -> Pair VarSet
    not_covered_invis_vis_tvs :: Pair VarSet
        , CoverageProblem -> FailedCoverageCondition
    not_covered_liberal       :: FailedCoverageCondition
        }

    -- | Which instance coverage condition failed? Was it the liberal
    -- coverage condition?
    data FailedCoverageCondition
      -- | Failed the instance coverage condition (ICC)
      = FailedICC
        { FailedCoverageCondition -> Bool
    alsoFailedLICC :: !Bool
          -- ^ Whether the instance also failed the LICC
        }
      -- | Failed the liberal instance coverage condition (LICC)
      | FailedLICC

    --------------------------------------------------------------------------------
    -- Template Haskell errors

    data THError
      -- | A syntax error with Template Haskel quotes & splices.
      -- See t'THSyntaxError'.
      = THSyntaxError !THSyntaxError
      -- | An error in Template Haskell involving 'Name's.
      -- See t'THNameError'.
      | THNameError !THNameError
      -- | An error in Template Haskell reification. See t'THReifyError'.
      | THReifyError !THReifyError
      -- | An error due to typing restrictions in Typed Template Haskell.
      -- See t'TypedTHError'.
      | TypedTHError !TypedTHError
      -- | An error occurred when trying to run a splice in Template Haskell.
      -- See 'SpliceFailReason'.
      | THSpliceFailed !SpliceFailReason
      -- | An error involving the 'addTopDecls' functionality. See t'AddTopDeclsError'.
      | AddTopDeclsError !AddTopDeclsError

      {-| IllegalStaticFormInSplice is an error when a user attempts to define
          a static pointer in a Template Haskell splice.

          Example(s):

         Test cases: th/TH_StaticPointers02
      -}
      | IllegalStaticFormInSplice !(HsExpr GhcPs)

      {-| FailedToLookupThInstName is a Template Haskell error that occurrs when looking up an
          instance fails.

          Example(s):

          Test cases: showIface/should_fail/THPutDocNonExistent
      -}
      | FailedToLookupThInstName !TH.Type !LookupTHInstNameErrReason

      {-| AddInvalidCorePlugin is a Template Haskell error indicating that a
          Core plugin being added has an invalid module due to being
          in the current package.

          Example(s):

          Test cases:
      -}
      | AddInvalidCorePlugin !String -- ^ Module name

      {-| AddDocToNonLocalDefn is a Template Haskell error for documentation being added to a
          definition which is not in the current module.

          Example(s):

          Test cases: showIface/should_fail/THPutDocExternal
      -}
      | AddDocToNonLocalDefn !TH.DocLoc

      {-| ReportCustomQuasiError is an error or warning thrown using 'qReport' from
          the 'Quasi' instance of 'TcM'.

          Example(s):

          Test cases:
      -}
      | ReportCustomQuasiError
        !Bool -- ^ True => Error, False => Warning
        !String -- ^ Error body
      deriving (forall x. THError -> Rep THError x)
    -> (forall x. Rep THError x -> THError) -> Generic THError
    forall x. Rep THError x -> THError
    forall x. THError -> Rep THError x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. THError -> Rep THError x
    from :: forall x. THError -> Rep THError x
    $cto :: forall x. Rep THError x -> THError
    to :: forall x. Rep THError x -> THError
    Generic

    -- | An error involving Template Haskell quotes or splices, e.g. nested
    -- quotation brackets or the use of an untyped bracket inside a typed splice.
    data THSyntaxError
      = {-| IllegalTHQuotes is an error that occurs when a Template Haskell
            quote is used without the TemplateHaskell extension enabled.

            Test case: T18251e
        -}
        IllegalTHQuotes !(HsExpr GhcPs)

        {-| IllegalTHSplice is an error that occurs when a Template Haskell
            splice occurs without having enabled the TemplateHaskell extension.

            Test cases:
              bkpfail01, bkpfail05, bkpfail09, bkpfail16, bkpfail35, bkpcabal06
        -}
      | IllegalTHSplice

        {-| NestedTHBrackets is an error that occurs when Template Haskell
            brackets are nested without any intervening splices.

            Example:

              foo = [| [| 'x' |] |]

            Test cases: TH_NestedSplicesFail{5,6,7,8}
        -}
      | NestedTHBrackets

      {-| MismatchedSpliceType is an error that happens when a typed bracket
          or splice is used inside a typed splice/bracket, or the other way around.

          Examples:

            f1 = [| $$x |]
            f2 = [|| $y ||]
            f3 = $$( [| 'x' |] )
            f4 = $( [|| 'y' ||] )

          Test cases: TH_NestedSplicesFail{1,2,3,4}
      -}
      | MismatchedSpliceType
          SpliceType -- ^ type of the splice
          SpliceOrBracket -- ^ what's nested inside
      {-| BadImplicitSplice is an error thrown when a user uses top-level implicit
          TH-splice without enabling the TemplateHaskell extension.

          Example:

            pure [] -- on top-level

          Test cases: ghci/prog019/prog019
                      ghci/scripts/T1914
                      ghci/scripts/T6106
                      rename/should_fail/T4042
                      rename/should_fail/T12146
      -}
      | BadImplicitSplice
      deriving (forall x. THSyntaxError -> Rep THSyntaxError x)
    -> (forall x. Rep THSyntaxError x -> THSyntaxError)
    -> Generic THSyntaxError
    forall x. Rep THSyntaxError x -> THSyntaxError
    forall x. THSyntaxError -> Rep THSyntaxError x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. THSyntaxError -> Rep THSyntaxError x
    from :: forall x. THSyntaxError -> Rep THSyntaxError x
    $cto :: forall x. Rep THSyntaxError x -> THSyntaxError
    to :: forall x. Rep THSyntaxError x -> THSyntaxError
    Generic

    data THNameError
      {-| NonExactName is a Template Haskell error that occurs when the user
          attempts to define a binder with a 'RdrName' that is not an exact 'Name'.

          Example(s):

          Test cases:
      -}
      = NonExactName !RdrName

      {-| QuotedNameWrongStage is an error that can happen when a
          (non-top-level) Name is used at a different Template Haskell stage
          than the stage at which it is bound.

         Test cases: T16976z
      -}
      | QuotedNameWrongStage !(HsQuote GhcPs)
      deriving (forall x. THNameError -> Rep THNameError x)
    -> (forall x. Rep THNameError x -> THNameError)
    -> Generic THNameError
    forall x. Rep THNameError x -> THNameError
    forall x. THNameError -> Rep THNameError x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. THNameError -> Rep THNameError x
    from :: forall x. THNameError -> Rep THNameError x
    $cto :: forall x. Rep THNameError x -> THNameError
    to :: forall x. Rep THNameError x -> THNameError
    Generic

    data THReifyError
      = {-| CannotReifyInstance is a Template Haskell error for when an instance being reified
            via `reifyInstances` is not a class constraint or type family application.

            Example(s):

           Test cases:
        -}
        CannotReifyInstance !Type

      {-| CannotReifyOutOfScopeThing is a Template Haskell error indicating
          that the given name is not in scope and therefore cannot be reified.

          Example(s):

         Test cases: th/T16976f
      -}
     | CannotReifyOutOfScopeThing !TH.Name

      {-| CannotReifyThingNotInTypeEnv is a Template Haskell error occurring
          when the given name is not in the type environment and therefore cannot be reified.

          Example(s):

         Test cases:
      -}
      | CannotReifyThingNotInTypeEnv !Name

      {-| NoRolesAssociatedWithName is a Template Haskell error for when the user
          tries to reify the roles of a given name but it is not something that has
          roles associated with it.

          Example(s):

         Test cases:
      -}
      | NoRolesAssociatedWithThing !TcTyThing

      {-| CannotRepresentThing is a Template Haskell error indicating that a
          type cannot be reified because it does not have a representation in Template Haskell.

          Example(s):

         Test cases:
      -}
      | CannotRepresentType !UnrepresentableTypeDescr !Type
      deriving (forall x. THReifyError -> Rep THReifyError x)
    -> (forall x. Rep THReifyError x -> THReifyError)
    -> Generic THReifyError
    forall x. Rep THReifyError x -> THReifyError
    forall x. THReifyError -> Rep THReifyError x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. THReifyError -> Rep THReifyError x
    from :: forall x. THReifyError -> Rep THReifyError x
    $cto :: forall x. Rep THReifyError x -> THReifyError
    to :: forall x. Rep THReifyError x -> THReifyError
    Generic

    data AddTopDeclsError
      = {-| InvalidTopDecl is a Template Haskell error occurring when one of the 'Dec's passed to
          'addTopDecls' is not a function, value, annotation, or foreign import declaration.

           Example(s):

           Test cases:
        -}
        InvalidTopDecl !(HsDecl GhcPs)
        {-| UnexpectedDeclarationSplice is an error that occurs when a Template Haskell
            splice appears inside top-level declarations added with 'addTopDecls'.

            Example(s): none

            Test cases: none
      -}
      | AddTopDeclsUnexpectedDeclarationSplice

      | AddTopDeclsRunSpliceFailure !RunSpliceFailReason
      deriving (forall x. AddTopDeclsError -> Rep AddTopDeclsError x)
    -> (forall x. Rep AddTopDeclsError x -> AddTopDeclsError)
    -> Generic AddTopDeclsError
    forall x. Rep AddTopDeclsError x -> AddTopDeclsError
    forall x. AddTopDeclsError -> Rep AddTopDeclsError x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. AddTopDeclsError -> Rep AddTopDeclsError x
    from :: forall x. AddTopDeclsError -> Rep AddTopDeclsError x
    $cto :: forall x. Rep AddTopDeclsError x -> AddTopDeclsError
    to :: forall x. Rep AddTopDeclsError x -> AddTopDeclsError
    Generic

    data TypedTHError
      = {-| SplicePolymorphicLocalVar is the error that occurs when the expression
            inside typed Template Haskell brackets is a polymorphic local variable.

            Example(s):
            x = \(y :: forall a. a -> a) -> [|| y ||]

           Test cases: quotes/T10384
        -}
        SplicePolymorphicLocalVar !Id

        {-| TypedTHWithPolyType is an error that signifies the illegal use
            of a polytype in a typed Template Haskell expression.

            Example(s):
            bad :: (forall a. a -> a) -> ()
            bad = $$( [|| \_ -> () ||] )

           Test cases: th/T11452
        -}
      | TypedTHWithPolyType !TcType
      deriving (forall x. TypedTHError -> Rep TypedTHError x)
    -> (forall x. Rep TypedTHError x -> TypedTHError)
    -> Generic TypedTHError
    forall x. Rep TypedTHError x -> TypedTHError
    forall x. TypedTHError -> Rep TypedTHError x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. TypedTHError -> Rep TypedTHError x
    from :: forall x. TypedTHError -> Rep TypedTHError x
    $cto :: forall x. Rep TypedTHError x -> TypedTHError
    to :: forall x. Rep TypedTHError x -> TypedTHError
    Generic

    data SpliceFailReason
      = {-| SpliceThrewException is an error that occurs when running a Template
            Haskell splice throws an exception.

            Example(s):

           Test cases: annotations/should_fail/annfail12
                       perf/compiler/MultiLayerModulesTH_Make
                       perf/compiler/MultiLayerModulesTH_OneShot
                       th/T10796b
                       th/T19470
                       th/T19709d
                       th/T5358
                       th/T5976
                       th/T7276a
                       th/T8987
                       th/TH_exn1
                       th/TH_exn2
                       th/TH_runIO
      -}
      SpliceThrewException
        !SplicePhase
        !SomeException
        !String -- ^ Result of showing the exception (cannot be done safely outside IO)
        !(LHsExpr GhcTc)
        !Bool -- True <=> Print the expression

      {-| RunSpliceFailure is an error indicating that a Template Haskell splice
          failed to be converted into a valid expression.

          Example(s):

         Test cases: th/T10828a
                     th/T10828b
                     th/T12478_4
                     th/T15270A
                     th/T15270B
                     th/T16895a
                     th/T16895b
                     th/T16895c
                     th/T16895d
                     th/T16895e
                     th/T18740d
                     th/T2597b
                     th/T2674
                     th/T3395
                     th/T7484
                     th/T7667a
                     th/TH_implicitParamsErr1
                     th/TH_implicitParamsErr2
                     th/TH_implicitParamsErr3
                     th/TH_invalid_add_top_decl
      -}
      | RunSpliceFailure !RunSpliceFailReason
      deriving (forall x. SpliceFailReason -> Rep SpliceFailReason x)
    -> (forall x. Rep SpliceFailReason x -> SpliceFailReason)
    -> Generic SpliceFailReason
    forall x. Rep SpliceFailReason x -> SpliceFailReason
    forall x. SpliceFailReason -> Rep SpliceFailReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. SpliceFailReason -> Rep SpliceFailReason x
    from :: forall x. SpliceFailReason -> Rep SpliceFailReason x
    $cto :: forall x. Rep SpliceFailReason x -> SpliceFailReason
    to :: forall x. Rep SpliceFailReason x -> SpliceFailReason
    Generic

    data RunSpliceFailReason
      = ConversionFail !ThingBeingConverted !ConversionFailReason
      deriving (forall x. RunSpliceFailReason -> Rep RunSpliceFailReason x)
    -> (forall x. Rep RunSpliceFailReason x -> RunSpliceFailReason)
    -> Generic RunSpliceFailReason
    forall x. Rep RunSpliceFailReason x -> RunSpliceFailReason
    forall x. RunSpliceFailReason -> Rep RunSpliceFailReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. RunSpliceFailReason -> Rep RunSpliceFailReason x
    from :: forall x. RunSpliceFailReason -> Rep RunSpliceFailReason x
    $cto :: forall x. Rep RunSpliceFailReason x -> RunSpliceFailReason
    to :: forall x. Rep RunSpliceFailReason x -> RunSpliceFailReason
    Generic

    -- | Identifies the TH splice attempting to be converted
    data ThingBeingConverted
      = ConvDec !TH.Dec
      | ConvExp !TH.Exp
      | ConvPat !TH.Pat
      | ConvType !TH.Type

    -- | The reason a TH splice could not be converted to a Haskell expression
    data ConversionFailReason
      = IllegalOccName !OccName.NameSpace !String
      | SumAltArityExceeded !TH.SumAlt !TH.SumArity
      | IllegalSumAlt !TH.SumAlt
      | IllegalSumArity !TH.SumArity
      | MalformedType !TypeOrKind !TH.Type
      | IllegalLastStatement !HsDoFlavour !(LStmt GhcPs (LHsExpr GhcPs))
      | KindSigsOnlyAllowedOnGADTs
      | IllegalDeclaration !THDeclDescriptor !IllegalDecls
      | CannotMixGADTConsWith98Cons
      | EmptyStmtListInDoBlock
      | NonVarInInfixExpr
      | MultiWayIfWithoutAlts
      | CasesExprWithoutAlts
      | ImplicitParamsWithOtherBinds
      | InvalidCCallImpent !String -- ^ Source
      | RecGadtNoCons
      | GadtNoCons
      | InvalidTypeInstanceHeader !TH.Type
      | InvalidTyFamInstLHS !TH.Type
      | InvalidImplicitParamBinding
      | DefaultDataInstDecl ![LDataFamInstDecl GhcPs]
      | FunBindLacksEquations !TH.Name
      deriving (forall x. ConversionFailReason -> Rep ConversionFailReason x)
    -> (forall x. Rep ConversionFailReason x -> ConversionFailReason)
    -> Generic ConversionFailReason
    forall x. Rep ConversionFailReason x -> ConversionFailReason
    forall x. ConversionFailReason -> Rep ConversionFailReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x. ConversionFailReason -> Rep ConversionFailReason x
    from :: forall x. ConversionFailReason -> Rep ConversionFailReason x
    $cto :: forall x. Rep ConversionFailReason x -> ConversionFailReason
    to :: forall x. Rep ConversionFailReason x -> ConversionFailReason
    Generic

    data IllegalDecls
      = IllegalDecls    !(NE.NonEmpty (LHsDecl GhcPs))
      | IllegalFamDecls !(NE.NonEmpty (LFamilyDecl GhcPs))

    -- | Label for a TH declaration
    data THDeclDescriptor
      = InstanceDecl
      | WhereClause
      | LetBinding
      | LetExpression
      | ClssDecl

    -- | The phase in which an exception was encountered when dealing with a TH splice
    data SplicePhase
      = SplicePhase_Run
      | SplicePhase_CompileAndLink

    data LookupTHInstNameErrReason
      = NoMatchesFound
      | CouldNotDetermineInstance

    data UnrepresentableTypeDescr
      = LinearInvisibleArgument
      | CoercionsInTypes

    -- FFI error types
    data IllegalForeignTypeReason
      = TypeCannotBeMarshaled !Type TypeCannotBeMarshaledReason
      | ForeignDynNotPtr
          !Type -- ^ Expected type
          !Type -- ^ Actual type
      | SafeHaskellMustBeInIO
      | IOResultExpected
      | UnexpectedNestedForall
      | LinearTypesNotAllowed
      | OneArgExpected
      | AtLeastOneArgExpected
      deriving (forall x.
     IllegalForeignTypeReason -> Rep IllegalForeignTypeReason x)
    -> (forall x.
        Rep IllegalForeignTypeReason x -> IllegalForeignTypeReason)
    -> Generic IllegalForeignTypeReason
    forall x.
    Rep IllegalForeignTypeReason x -> IllegalForeignTypeReason
    forall x.
    IllegalForeignTypeReason -> Rep IllegalForeignTypeReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x.
    IllegalForeignTypeReason -> Rep IllegalForeignTypeReason x
    from :: forall x.
    IllegalForeignTypeReason -> Rep IllegalForeignTypeReason x
    $cto :: forall x.
    Rep IllegalForeignTypeReason x -> IllegalForeignTypeReason
    to :: forall x.
    Rep IllegalForeignTypeReason x -> IllegalForeignTypeReason
    Generic

    -- | Reason why a type cannot be marshalled through the FFI.
    data TypeCannotBeMarshaledReason
      = NotADataType
      | NewtypeDataConNotInScope !TyCon ![Type]
      | UnliftedFFITypesNeeded
      | NotABoxedMarshalableTyCon
      | ForeignLabelNotAPtr
      | NotSimpleUnliftedType
      | NotBoxedKindAny
      deriving (forall x.
     TypeCannotBeMarshaledReason -> Rep TypeCannotBeMarshaledReason x)
    -> (forall x.
        Rep TypeCannotBeMarshaledReason x -> TypeCannotBeMarshaledReason)
    -> Generic TypeCannotBeMarshaledReason
    forall x.
    Rep TypeCannotBeMarshaledReason x -> TypeCannotBeMarshaledReason
    forall x.
    TypeCannotBeMarshaledReason -> Rep TypeCannotBeMarshaledReason x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    $cfrom :: forall x.
    TypeCannotBeMarshaledReason -> Rep TypeCannotBeMarshaledReason x
    from :: forall x.
    TypeCannotBeMarshaledReason -> Rep TypeCannotBeMarshaledReason x
    $cto :: forall x.
    Rep TypeCannotBeMarshaledReason x -> TypeCannotBeMarshaledReason
    to :: forall x.
    Rep TypeCannotBeMarshaledReason x -> TypeCannotBeMarshaledReason
    Generic