{-# LANGUAGE LambdaCase #-} {-# OPTIONS_GHC -fno-warn-orphans #-} -- instance Diagnostic TcRnMessage {-# LANGUAGE RecordWildCards #-} module GHC.Tc.Errors.Ppr ( pprTypeDoesNotHaveFixedRuntimeRep ) where import GHC.Prelude import Data.Maybe (isJust) import GHC.Builtin.Names import GHC.Core.Class (Class(..)) import GHC.Core.Coercion (pprCoAxBranchUser) import GHC.Core.Coercion.Axiom (coAxiomTyCon, coAxiomSingleBranch) import GHC.Core.DataCon (DataCon) import GHC.Core.FamInstEnv (famInstAxiom) import GHC.Core.InstEnv import GHC.Core.TyCon (isNewTyCon) import GHC.Core.TyCo.Ppr (pprKind, pprParendType, pprType, pprWithExplicitKindsWhen, pprTheta, pprClassPred, pprTypeApp, pprSourceTyCon) import GHC.Core.Type import GHC.Data.Bag import GHC.Tc.Errors.Types import GHC.Tc.Types.Rank (Rank(..)) import GHC.Tc.Utils.TcType (TcType, tcSplitForAllTyVars, mkClassPred) import GHC.Types.Error import GHC.Types.FieldLabel (FieldLabelString, flIsOverloaded, flSelector) import GHC.Types.Id (isRecordSelector) import GHC.Types.Name import GHC.Types.Name.Reader (GreName(..), pprNameProvenance) import GHC.Types.SrcLoc (GenLocated(..), unLoc) import GHC.Types.TyThing import GHC.Types.Var.Env (emptyTidyEnv) import GHC.Types.Var.Set (pprVarSet, pluralVarSet) import GHC.Driver.Flags import GHC.Hs import GHC.Utils.Misc (capitalise) import GHC.Utils.Outputable import GHC.Unit.State (pprWithUnitState, UnitState) import qualified GHC.LanguageExtensions as LangExt import qualified Data.List.NonEmpty as NE instance Diagnostic TcRnMessage where diagnosticMessage = \case TcRnUnknownMessage m -> diagnosticMessage m TcRnTypeDoesNotHaveFixedRuntimeRep ty prov (ErrInfo extra supplementary) -> mkDecorated [pprTypeDoesNotHaveFixedRuntimeRep ty prov, extra, supplementary] TcRnMessageWithInfo unit_state msg_with_info -> case msg_with_info of TcRnMessageDetailed err_info msg -> messageWithInfoDiagnosticMessage unit_state err_info (diagnosticMessage msg) TcRnImplicitLift id_or_name ErrInfo{..} -> mkDecorated $ ( text "The variable" <+> quotes (ppr id_or_name) <+> text "is implicitly lifted in the TH quotation" ) : [errInfoContext, errInfoSupplementary] TcRnUnusedPatternBinds bind -> mkDecorated [hang (text "This pattern-binding binds no variables:") 2 (ppr bind)] TcRnDodgyImports name -> mkDecorated [dodgy_msg (text "import") name (dodgy_msg_insert name :: IE GhcPs)] TcRnDodgyExports name -> mkDecorated [dodgy_msg (text "export") name (dodgy_msg_insert name :: IE GhcRn)] TcRnMissingImportList ie -> mkDecorated [ text "The import item" <+> quotes (ppr ie) <+> text "does not have an explicit import list" ] TcRnUnsafeDueToPlugin -> mkDecorated [text "Use of plugins makes the module unsafe"] TcRnModMissingRealSrcSpan mod -> mkDecorated [text "Module does not have a RealSrcSpan:" <+> ppr mod] TcRnIdNotExportedFromModuleSig name mod -> mkDecorated [ text "The identifier" <+> ppr (occName name) <+> text "does not exist in the signature for" <+> ppr mod ] TcRnIdNotExportedFromLocalSig name -> mkDecorated [ text "The identifier" <+> ppr (occName name) <+> text "does not exist in the local signature." ] TcRnShadowedName occ provenance -> let shadowed_locs = case provenance of ShadowedNameProvenanceLocal n -> [text "bound at" <+> ppr n] ShadowedNameProvenanceGlobal gres -> map pprNameProvenance gres in mkSimpleDecorated $ sep [text "This binding for" <+> quotes (ppr occ) <+> text "shadows the existing binding" <> plural shadowed_locs, nest 2 (vcat shadowed_locs)] TcRnDuplicateWarningDecls d rdr_name -> mkSimpleDecorated $ vcat [text "Multiple warning declarations for" <+> quotes (ppr rdr_name), text "also at " <+> ppr (getLocA d)] TcRnSimplifierTooManyIterations simples limit wc -> mkSimpleDecorated $ hang (text "solveWanteds: too many iterations" <+> parens (text "limit =" <+> ppr limit)) 2 (vcat [ text "Unsolved:" <+> ppr wc , text "Simples:" <+> ppr simples ]) TcRnIllegalPatSynDecl rdrname -> mkSimpleDecorated $ hang (text "Illegal pattern synonym declaration for" <+> quotes (ppr rdrname)) 2 (text "Pattern synonym declarations are only valid at top level") TcRnLinearPatSyn ty -> mkSimpleDecorated $ hang (text "Pattern synonyms do not support linear fields (GHC #18806):") 2 (ppr ty) TcRnEmptyRecordUpdate -> mkSimpleDecorated $ text "Empty record update" TcRnIllegalFieldPunning fld -> mkSimpleDecorated $ text "Illegal use of punning for field" <+> quotes (ppr fld) TcRnIllegalWildcardsInRecord fld_part -> mkSimpleDecorated $ text "Illegal `..' in record" <+> pprRecordFieldPart fld_part TcRnDuplicateFieldName fld_part dups -> mkSimpleDecorated $ hsep [text "duplicate field name", quotes (ppr (NE.head dups)), text "in record", pprRecordFieldPart fld_part] TcRnIllegalViewPattern pat -> mkSimpleDecorated $ vcat [text "Illegal view pattern: " <+> ppr pat] TcRnCharLiteralOutOfRange c -> mkSimpleDecorated $ text "character literal out of range: '\\" <> char c <> char '\'' TcRnIllegalWildcardsInConstructor con -> mkSimpleDecorated $ vcat [ text "Illegal `..' notation for constructor" <+> quotes (ppr con) , nest 2 (text "The constructor has no labelled fields") ] TcRnIgnoringAnnotations anns -> mkSimpleDecorated $ text "Ignoring ANN annotation" <> plural anns <> comma <+> text "because this is a stage-1 compiler without -fexternal-interpreter or doesn't support GHCi" TcRnAnnotationInSafeHaskell -> mkSimpleDecorated $ vcat [ text "Annotations are not compatible with Safe Haskell." , text "See https://gitlab.haskell.org/ghc/ghc/issues/10826" ] TcRnInvalidTypeApplication fun_ty hs_ty -> mkSimpleDecorated $ text "Cannot apply expression of type" <+> quotes (ppr fun_ty) $$ text "to a visible type argument" <+> quotes (ppr hs_ty) TcRnTagToEnumMissingValArg -> mkSimpleDecorated $ text "tagToEnum# must appear applied to one value argument" TcRnTagToEnumUnspecifiedResTy ty -> mkSimpleDecorated $ hang (text "Bad call to tagToEnum# at type" <+> ppr ty) 2 (vcat [ text "Specify the type by giving a type signature" , text "e.g. (tagToEnum# x) :: Bool" ]) TcRnTagToEnumResTyNotAnEnum ty -> mkSimpleDecorated $ hang (text "Bad call to tagToEnum# at type" <+> ppr ty) 2 (text "Result type must be an enumeration type") TcRnArrowIfThenElsePredDependsOnResultTy -> mkSimpleDecorated $ text "Predicate type of `ifThenElse' depends on result type" TcRnArrowCommandExpected cmd -> mkSimpleDecorated $ vcat [text "The expression", nest 2 (ppr cmd), text "was found where an arrow command was expected"] TcRnIllegalHsBootFileDecl -> mkSimpleDecorated $ text "Illegal declarations in an hs-boot file" TcRnRecursivePatternSynonym binds -> mkSimpleDecorated $ hang (text "Recursive pattern synonym definition with following bindings:") 2 (vcat $ map pprLBind . bagToList $ binds) where pprLoc loc = parens (text "defined at" <+> ppr loc) pprLBind :: GenLocated (SrcSpanAnn' a) (HsBindLR GhcRn idR) -> SDoc pprLBind (L loc bind) = pprWithCommas ppr (collectHsBindBinders CollNoDictBinders bind) <+> pprLoc (locA loc) TcRnPartialTypeSigTyVarMismatch n1 n2 fn_name hs_ty -> mkSimpleDecorated $ hang (text "Couldn't match" <+> quotes (ppr n1) <+> text "with" <+> quotes (ppr n2)) 2 (hang (text "both bound by the partial type signature:") 2 (ppr fn_name <+> dcolon <+> ppr hs_ty)) TcRnPartialTypeSigBadQuantifier n fn_name hs_ty -> mkSimpleDecorated $ hang (text "Can't quantify over" <+> quotes (ppr n)) 2 (hang (text "bound by the partial type signature:") 2 (ppr fn_name <+> dcolon <+> ppr hs_ty)) TcRnPolymorphicBinderMissingSig n ty -> mkSimpleDecorated $ sep [ text "Polymorphic local binding with no type signature:" , nest 2 $ pprPrefixName n <+> dcolon <+> ppr ty ] TcRnOverloadedSig sig -> mkSimpleDecorated $ hang (text "Overloaded signature conflicts with monomorphism restriction") 2 (ppr sig) TcRnTupleConstraintInst _ -> mkSimpleDecorated $ text "You can't specify an instance for a tuple constraint" TcRnAbstractClassInst clas -> mkSimpleDecorated $ text "Cannot define instance for abstract class" <+> quotes (ppr (className clas)) TcRnNoClassInstHead tau -> mkSimpleDecorated $ hang (text "Instance head is not headed by a class:") 2 (pprType tau) TcRnUserTypeError ty -> mkSimpleDecorated (pprUserTypeErrorTy ty) TcRnConstraintInKind ty -> mkSimpleDecorated $ text "Illegal constraint in a kind:" <+> pprType ty TcRnUnboxedTupleTypeFuncArg ty -> mkSimpleDecorated $ sep [ text "Illegal unboxed tuple type as function argument:" , pprType ty ] TcRnLinearFuncInKind ty -> mkSimpleDecorated $ text "Illegal linear function in a kind:" <+> pprType ty TcRnForAllEscapeError ty kind -> mkSimpleDecorated $ vcat [ hang (text "Quantified type's kind mentions quantified type variable") 2 (text "type:" <+> quotes (ppr ty)) , hang (text "where the body of the forall has this kind:") 2 (quotes (pprKind kind)) ] TcRnVDQInTermType ty -> mkSimpleDecorated $ vcat [ hang (text "Illegal visible, dependent quantification" <+> text "in the type of a term:") 2 (pprType ty) , text "(GHC does not yet support this)" ] TcRnIllegalEqualConstraints ty -> mkSimpleDecorated $ text "Illegal equational constraint" <+> pprType ty TcRnBadQuantPredHead ty -> mkSimpleDecorated $ hang (text "Quantified predicate must have a class or type variable head:") 2 (pprType ty) TcRnIllegalTupleConstraint ty -> mkSimpleDecorated $ text "Illegal tuple constraint:" <+> pprType ty TcRnNonTypeVarArgInConstraint ty -> mkSimpleDecorated $ hang (text "Non type-variable argument") 2 (text "in the constraint:" <+> pprType ty) TcRnIllegalImplicitParam ty -> mkSimpleDecorated $ text "Illegal implicit parameter" <+> quotes (pprType ty) TcRnIllegalConstraintSynonymOfKind kind -> mkSimpleDecorated $ text "Illegal constraint synonym of kind:" <+> quotes (pprKind kind) TcRnIllegalClassInst tcf -> mkSimpleDecorated $ vcat [ text "Illegal instance for a" <+> ppr tcf , text "A class instance must be for a class" ] TcRnOversaturatedVisibleKindArg ty -> mkSimpleDecorated $ text "Illegal oversaturated visible kind argument:" <+> quotes (char '@' <> pprParendType ty) TcRnBadAssociatedType clas tc -> mkSimpleDecorated $ hsep [ text "Class", quotes (ppr clas) , text "does not have an associated type", quotes (ppr tc) ] TcRnForAllRankErr rank ty -> let herald = case tcSplitForAllTyVars ty of ([], _) -> text "Illegal qualified type:" _ -> text "Illegal polymorphic type:" extra = case rank of MonoTypeConstraint -> text "A constraint must be a monotype" _ -> empty in mkSimpleDecorated $ vcat [hang herald 2 (pprType ty), extra] TcRnMonomorphicBindings bindings -> let pp_bndrs = pprBindings bindings in mkSimpleDecorated $ sep [ text "The Monomorphism Restriction applies to the binding" <> plural bindings , text "for" <+> pp_bndrs ] TcRnOrphanInstance inst -> mkSimpleDecorated $ hsep [ text "Orphan instance:" , pprInstanceHdr inst ] TcRnFunDepConflict unit_state sorted -> let herald = text "Functional dependencies conflict between instance declarations:" in mkSimpleDecorated $ pprWithUnitState unit_state $ (hang herald 2 (pprInstances $ NE.toList sorted)) TcRnDupInstanceDecls unit_state sorted -> let herald = text "Duplicate instance declarations:" in mkSimpleDecorated $ pprWithUnitState unit_state $ (hang herald 2 (pprInstances $ NE.toList sorted)) TcRnConflictingFamInstDecls sortedNE -> let sorted = NE.toList sortedNE in mkSimpleDecorated $ hang (text "Conflicting family instance declarations:") 2 (vcat [ pprCoAxBranchUser (coAxiomTyCon ax) (coAxiomSingleBranch ax) | fi <- sorted , let ax = famInstAxiom fi ]) TcRnFamInstNotInjective rea fam_tc (eqn1 NE.:| rest_eqns) -> let (herald, show_kinds) = case rea of InjErrRhsBareTyVar tys -> (injectivityErrorHerald $$ text "RHS of injective type family equation is a bare" <+> text "type variable" $$ text "but these LHS type and kind patterns are not bare" <+> text "variables:" <+> pprQuotedList tys, False) InjErrRhsCannotBeATypeFam -> (injectivityErrorHerald $$ text "RHS of injective type family equation cannot" <+> text "be a type family:", False) InjErrRhsOverlap -> (text "Type family equation right-hand sides overlap; this violates" $$ text "the family's injectivity annotation:", False) InjErrCannotInferFromRhs tvs has_kinds _ -> let show_kinds = has_kinds == YesHasKinds what = if show_kinds then text "Type/kind" else text "Type" body = sep [ what <+> text "variable" <> pluralVarSet tvs <+> pprVarSet tvs (pprQuotedList . scopedSort) , text "cannot be inferred from the right-hand side." ] in (injectivityErrorHerald $$ body $$ text "In the type family equation:", show_kinds) in mkSimpleDecorated $ pprWithExplicitKindsWhen show_kinds $ hang herald 2 (vcat (map (pprCoAxBranchUser fam_tc) (eqn1 : rest_eqns))) TcRnBangOnUnliftedType ty -> mkSimpleDecorated $ text "Strictness flag has no effect on unlifted type" <+> quotes (ppr ty) TcRnMultipleDefaultDeclarations dup_things -> mkSimpleDecorated $ hang (text "Multiple default declarations") 2 (vcat (map pp dup_things)) where pp :: LDefaultDecl GhcRn -> SDoc pp (L locn (DefaultDecl _ _)) = text "here was another default declaration" <+> ppr (locA locn) TcRnBadDefaultType ty deflt_clss -> mkSimpleDecorated $ hang (text "The default type" <+> quotes (ppr ty) <+> text "is not an instance of") 2 (foldr1 (\a b -> a <+> text "or" <+> b) (map (quotes. ppr) deflt_clss)) TcRnPatSynBundledWithNonDataCon -> mkSimpleDecorated $ text "Pattern synonyms can be bundled only with datatypes." TcRnPatSynBundledWithWrongType expected_res_ty res_ty -> mkSimpleDecorated $ text "Pattern synonyms can only be bundled with matching type constructors" $$ text "Couldn't match expected type of" <+> quotes (ppr expected_res_ty) <+> text "with actual type of" <+> quotes (ppr res_ty) TcRnDupeModuleExport mod -> mkSimpleDecorated $ hsep [ text "Duplicate" , quotes (text "Module" <+> ppr mod) , text "in export list" ] TcRnExportedModNotImported mod -> mkSimpleDecorated $ formatExportItemError (text "module" <+> ppr mod) "is not imported" TcRnNullExportedModule mod -> mkSimpleDecorated $ formatExportItemError (text "module" <+> ppr mod) "exports nothing" TcRnMissingExportList mod -> mkSimpleDecorated $ formatExportItemError (text "module" <+> ppr mod) "is missing an export list" TcRnExportHiddenComponents export_item -> mkSimpleDecorated $ formatExportItemError (ppr export_item) "attempts to export constructors or class methods that are not visible here" TcRnDuplicateExport child ie1 ie2 -> mkSimpleDecorated $ hsep [ quotes (ppr child) , text "is exported by", quotes (ppr ie1) , text "and", quotes (ppr ie2) ] TcRnExportedParentChildMismatch parent_name ty_thing child parent_names -> mkSimpleDecorated $ text "The type constructor" <+> quotes (ppr parent_name) <+> text "is not the parent of the" <+> text what_is <+> quotes thing <> char '.' $$ text (capitalise what_is) <> text "s can only be exported with their parent type constructor." $$ (case parents of [] -> empty [_] -> text "Parent:" _ -> text "Parents:") <+> fsep (punctuate comma parents) where pp_category :: TyThing -> String pp_category (AnId i) | isRecordSelector i = "record selector" pp_category i = tyThingCategory i what_is = pp_category ty_thing thing = ppr child parents = map ppr parent_names TcRnConflictingExports occ child1 gre1 ie1 child2 gre2 ie2 -> mkSimpleDecorated $ vcat [ text "Conflicting exports for" <+> quotes (ppr occ) <> colon , ppr_export child1 gre1 ie1 , ppr_export child2 gre2 ie2 ] where ppr_export child gre ie = nest 3 (hang (quotes (ppr ie) <+> text "exports" <+> quotes (ppr_name child)) 2 (pprNameProvenance gre)) -- DuplicateRecordFields means that nameOccName might be a mangled -- $sel-prefixed thing, in which case show the correct OccName alone -- (but otherwise show the Name so it will have a module qualifier) ppr_name (FieldGreName fl) | flIsOverloaded fl = ppr fl | otherwise = ppr (flSelector fl) ppr_name (NormalGreName name) = ppr name TcRnAmbiguousField rupd parent_type -> mkSimpleDecorated $ vcat [ text "The record update" <+> ppr rupd <+> text "with type" <+> ppr parent_type <+> text "is ambiguous." , text "This will not be supported by -XDuplicateRecordFields in future releases of GHC." ] TcRnMissingFields con fields -> mkSimpleDecorated $ vcat [header, nest 2 rest] where rest | null fields = empty | otherwise = vcat (fmap pprField fields) header = text "Fields of" <+> quotes (ppr con) <+> text "not initialised" <> if null fields then empty else colon TcRnFieldUpdateInvalidType prs -> mkSimpleDecorated $ hang (text "Record update for insufficiently polymorphic field" <> plural prs <> colon) 2 (vcat [ ppr f <+> dcolon <+> ppr ty | (f,ty) <- prs ]) TcRnNoConstructorHasAllFields conflictingFields -> mkSimpleDecorated $ hang (text "No constructor has all these fields:") 2 (pprQuotedList conflictingFields) TcRnMixedSelectors data_name data_sels pat_name pat_syn_sels -> mkSimpleDecorated $ text "Cannot use a mixture of pattern synonym and record selectors" $$ text "Record selectors defined by" <+> quotes (ppr data_name) <> colon <+> pprWithCommas ppr data_sels $$ text "Pattern synonym selectors defined by" <+> quotes (ppr pat_name) <> colon <+> pprWithCommas ppr pat_syn_sels TcRnMissingStrictFields con fields -> mkSimpleDecorated $ vcat [header, nest 2 rest] where rest | null fields = empty -- Happens for non-record constructors -- with strict fields | otherwise = vcat (fmap pprField fields) header = text "Constructor" <+> quotes (ppr con) <+> text "does not have the required strict field(s)" <> if null fields then empty else colon TcRnNoPossibleParentForFields rbinds -> mkSimpleDecorated $ hang (text "No type has all these fields:") 2 (pprQuotedList fields) where fields = map (hfbLHS . unLoc) rbinds TcRnBadOverloadedRecordUpdate _rbinds -> mkSimpleDecorated $ text "Record update is ambiguous, and requires a type signature" TcRnStaticFormNotClosed name reason -> mkSimpleDecorated $ quotes (ppr name) <+> text "is used in a static form but it is not closed" <+> text "because it" $$ sep (causes reason) where causes :: NotClosedReason -> [SDoc] causes NotLetBoundReason = [text "is not let-bound."] causes (NotTypeClosed vs) = [ text "has a non-closed type because it contains the" , text "type variables:" <+> pprVarSet vs (hsep . punctuate comma . map (quotes . ppr)) ] causes (NotClosed n reason) = let msg = text "uses" <+> quotes (ppr n) <+> text "which" in case reason of NotClosed _ _ -> msg : causes reason _ -> let (xs0, xs1) = splitAt 1 $ causes reason in fmap (msg <+>) xs0 ++ xs1 TcRnUselessTypeable -> mkSimpleDecorated $ text "Deriving" <+> quotes (ppr typeableClassName) <+> text "has no effect: all types now auto-derive Typeable" TcRnDerivingDefaults cls -> mkSimpleDecorated $ sep [ text "Both DeriveAnyClass and" <+> text "GeneralizedNewtypeDeriving are enabled" , text "Defaulting to the DeriveAnyClass strategy" <+> text "for instantiating" <+> ppr cls ] TcRnNonUnaryTypeclassConstraint ct -> mkSimpleDecorated $ quotes (ppr ct) <+> text "is not a unary constraint, as expected by a deriving clause" TcRnPartialTypeSignatures _ theta -> mkSimpleDecorated $ text "Found type wildcard" <+> quotes (char '_') <+> text "standing for" <+> quotes (pprTheta theta) TcRnCannotDeriveInstance cls cls_tys mb_strat newtype_deriving reason -> mkSimpleDecorated $ derivErrDiagnosticMessage cls cls_tys mb_strat newtype_deriving True reason TcRnLazyGADTPattern -> mkSimpleDecorated $ hang (text "An existential or GADT data constructor cannot be used") 2 (text "inside a lazy (~) pattern") TcRnArrowProcGADTPattern -> mkSimpleDecorated $ text "Proc patterns cannot use existential or GADT data constructors" TcRnSpecialClassInst cls because_safeHaskell -> mkSimpleDecorated $ text "Class" <+> quotes (ppr $ className cls) <+> text "does not support user-specified instances" <> safeHaskell_msg where safeHaskell_msg | because_safeHaskell = text " when Safe Haskell is enabled." | otherwise = dot TcRnForallIdentifier rdr_name -> mkSimpleDecorated $ fsep [ text "The use of" <+> quotes (ppr rdr_name) <+> text "as an identifier", text "will become an error in a future GHC release." ] TcRnGADTMonoLocalBinds -> mkSimpleDecorated $ fsep [ text "Pattern matching on GADTs without MonoLocalBinds" , text "is fragile." ] diagnosticReason = \case TcRnUnknownMessage m -> diagnosticReason m TcRnTypeDoesNotHaveFixedRuntimeRep{} -> ErrorWithoutFlag TcRnMessageWithInfo _ msg_with_info -> case msg_with_info of TcRnMessageDetailed _ m -> diagnosticReason m TcRnImplicitLift{} -> WarningWithFlag Opt_WarnImplicitLift TcRnUnusedPatternBinds{} -> WarningWithFlag Opt_WarnUnusedPatternBinds TcRnDodgyImports{} -> WarningWithFlag Opt_WarnDodgyImports TcRnDodgyExports{} -> WarningWithFlag Opt_WarnDodgyExports TcRnMissingImportList{} -> WarningWithFlag Opt_WarnMissingImportList TcRnUnsafeDueToPlugin{} -> WarningWithoutFlag TcRnModMissingRealSrcSpan{} -> ErrorWithoutFlag TcRnIdNotExportedFromModuleSig{} -> ErrorWithoutFlag TcRnIdNotExportedFromLocalSig{} -> ErrorWithoutFlag TcRnShadowedName{} -> WarningWithFlag Opt_WarnNameShadowing TcRnDuplicateWarningDecls{} -> ErrorWithoutFlag TcRnSimplifierTooManyIterations{} -> ErrorWithoutFlag TcRnIllegalPatSynDecl{} -> ErrorWithoutFlag TcRnLinearPatSyn{} -> ErrorWithoutFlag TcRnEmptyRecordUpdate -> ErrorWithoutFlag TcRnIllegalFieldPunning{} -> ErrorWithoutFlag TcRnIllegalWildcardsInRecord{} -> ErrorWithoutFlag TcRnDuplicateFieldName{} -> ErrorWithoutFlag TcRnIllegalViewPattern{} -> ErrorWithoutFlag TcRnCharLiteralOutOfRange{} -> ErrorWithoutFlag TcRnIllegalWildcardsInConstructor{} -> ErrorWithoutFlag TcRnIgnoringAnnotations{} -> WarningWithoutFlag TcRnAnnotationInSafeHaskell -> ErrorWithoutFlag TcRnInvalidTypeApplication{} -> ErrorWithoutFlag TcRnTagToEnumMissingValArg -> ErrorWithoutFlag TcRnTagToEnumUnspecifiedResTy{} -> ErrorWithoutFlag TcRnTagToEnumResTyNotAnEnum{} -> ErrorWithoutFlag TcRnArrowIfThenElsePredDependsOnResultTy -> ErrorWithoutFlag TcRnArrowCommandExpected{} -> ErrorWithoutFlag TcRnIllegalHsBootFileDecl -> ErrorWithoutFlag TcRnRecursivePatternSynonym{} -> ErrorWithoutFlag TcRnPartialTypeSigTyVarMismatch{} -> ErrorWithoutFlag TcRnPartialTypeSigBadQuantifier{} -> ErrorWithoutFlag TcRnPolymorphicBinderMissingSig{} -> WarningWithFlag Opt_WarnMissingLocalSignatures TcRnOverloadedSig{} -> ErrorWithoutFlag TcRnTupleConstraintInst{} -> ErrorWithoutFlag TcRnAbstractClassInst{} -> ErrorWithoutFlag TcRnNoClassInstHead{} -> ErrorWithoutFlag TcRnUserTypeError{} -> ErrorWithoutFlag TcRnConstraintInKind{} -> ErrorWithoutFlag TcRnUnboxedTupleTypeFuncArg{} -> ErrorWithoutFlag TcRnLinearFuncInKind{} -> ErrorWithoutFlag TcRnForAllEscapeError{} -> ErrorWithoutFlag TcRnVDQInTermType{} -> ErrorWithoutFlag TcRnIllegalEqualConstraints{} -> ErrorWithoutFlag TcRnBadQuantPredHead{} -> ErrorWithoutFlag TcRnIllegalTupleConstraint{} -> ErrorWithoutFlag TcRnNonTypeVarArgInConstraint{} -> ErrorWithoutFlag TcRnIllegalImplicitParam{} -> ErrorWithoutFlag TcRnIllegalConstraintSynonymOfKind{} -> ErrorWithoutFlag TcRnIllegalClassInst{} -> ErrorWithoutFlag TcRnOversaturatedVisibleKindArg{} -> ErrorWithoutFlag TcRnBadAssociatedType{} -> ErrorWithoutFlag TcRnForAllRankErr{} -> ErrorWithoutFlag TcRnMonomorphicBindings{} -> WarningWithFlag Opt_WarnMonomorphism TcRnOrphanInstance{} -> WarningWithFlag Opt_WarnOrphans TcRnFunDepConflict{} -> ErrorWithoutFlag TcRnDupInstanceDecls{} -> ErrorWithoutFlag TcRnConflictingFamInstDecls{} -> ErrorWithoutFlag TcRnFamInstNotInjective{} -> ErrorWithoutFlag TcRnBangOnUnliftedType{} -> WarningWithFlag Opt_WarnRedundantStrictnessFlags TcRnMultipleDefaultDeclarations{} -> ErrorWithoutFlag TcRnBadDefaultType{} -> ErrorWithoutFlag TcRnPatSynBundledWithNonDataCon{} -> ErrorWithoutFlag TcRnPatSynBundledWithWrongType{} -> ErrorWithoutFlag TcRnDupeModuleExport{} -> WarningWithFlag Opt_WarnDuplicateExports TcRnExportedModNotImported{} -> ErrorWithoutFlag TcRnNullExportedModule{} -> WarningWithFlag Opt_WarnDodgyExports TcRnMissingExportList{} -> WarningWithFlag Opt_WarnMissingExportList TcRnExportHiddenComponents{} -> ErrorWithoutFlag TcRnDuplicateExport{} -> WarningWithFlag Opt_WarnDuplicateExports TcRnExportedParentChildMismatch{} -> ErrorWithoutFlag TcRnConflictingExports{} -> ErrorWithoutFlag TcRnAmbiguousField{} -> WarningWithFlag Opt_WarnAmbiguousFields TcRnMissingFields{} -> WarningWithFlag Opt_WarnMissingFields TcRnFieldUpdateInvalidType{} -> ErrorWithoutFlag TcRnNoConstructorHasAllFields{} -> ErrorWithoutFlag TcRnMixedSelectors{} -> ErrorWithoutFlag TcRnMissingStrictFields{} -> ErrorWithoutFlag TcRnNoPossibleParentForFields{} -> ErrorWithoutFlag TcRnBadOverloadedRecordUpdate{} -> ErrorWithoutFlag TcRnStaticFormNotClosed{} -> ErrorWithoutFlag TcRnUselessTypeable -> WarningWithFlag Opt_WarnDerivingTypeable TcRnDerivingDefaults{} -> WarningWithFlag Opt_WarnDerivingDefaults TcRnNonUnaryTypeclassConstraint{} -> ErrorWithoutFlag TcRnPartialTypeSignatures{} -> WarningWithFlag Opt_WarnPartialTypeSignatures TcRnCannotDeriveInstance _ _ _ _ rea -> case rea of DerivErrNotWellKinded{} -> ErrorWithoutFlag DerivErrSafeHaskellGenericInst -> ErrorWithoutFlag DerivErrDerivingViaWrongKind{} -> ErrorWithoutFlag DerivErrNoEtaReduce{} -> ErrorWithoutFlag DerivErrBootFileFound -> ErrorWithoutFlag DerivErrDataConsNotAllInScope{} -> ErrorWithoutFlag DerivErrGNDUsedOnData -> ErrorWithoutFlag DerivErrNullaryClasses -> ErrorWithoutFlag DerivErrLastArgMustBeApp -> ErrorWithoutFlag DerivErrNoFamilyInstance{} -> ErrorWithoutFlag DerivErrNotStockDeriveable{} -> ErrorWithoutFlag DerivErrHasAssociatedDatatypes{} -> ErrorWithoutFlag DerivErrNewtypeNonDeriveableClass -> ErrorWithoutFlag DerivErrCannotEtaReduceEnough{} -> ErrorWithoutFlag DerivErrOnlyAnyClassDeriveable{} -> ErrorWithoutFlag DerivErrNotDeriveable{} -> ErrorWithoutFlag DerivErrNotAClass{} -> ErrorWithoutFlag DerivErrNoConstructors{} -> ErrorWithoutFlag DerivErrLangExtRequired{} -> ErrorWithoutFlag DerivErrDunnoHowToDeriveForType{} -> ErrorWithoutFlag DerivErrMustBeEnumType{} -> ErrorWithoutFlag DerivErrMustHaveExactlyOneConstructor{} -> ErrorWithoutFlag DerivErrMustHaveSomeParameters{} -> ErrorWithoutFlag DerivErrMustNotHaveClassContext{} -> ErrorWithoutFlag DerivErrBadConstructor{} -> ErrorWithoutFlag DerivErrGenerics{} -> ErrorWithoutFlag DerivErrEnumOrProduct{} -> ErrorWithoutFlag TcRnLazyGADTPattern -> ErrorWithoutFlag TcRnArrowProcGADTPattern -> ErrorWithoutFlag TcRnSpecialClassInst {} -> ErrorWithoutFlag TcRnForallIdentifier {} -> WarningWithFlag Opt_WarnForallIdentifier TcRnGADTMonoLocalBinds {} -> WarningWithFlag Opt_WarnGADTMonoLocalBinds diagnosticHints = \case TcRnUnknownMessage m -> diagnosticHints m TcRnTypeDoesNotHaveFixedRuntimeRep{} -> noHints TcRnMessageWithInfo _ msg_with_info -> case msg_with_info of TcRnMessageDetailed _ m -> diagnosticHints m TcRnImplicitLift{} -> noHints TcRnUnusedPatternBinds{} -> noHints TcRnDodgyImports{} -> noHints TcRnDodgyExports{} -> noHints TcRnMissingImportList{} -> noHints TcRnUnsafeDueToPlugin{} -> noHints TcRnModMissingRealSrcSpan{} -> noHints TcRnIdNotExportedFromModuleSig name mod -> [SuggestAddToHSigExportList name $ Just mod] TcRnIdNotExportedFromLocalSig name -> [SuggestAddToHSigExportList name Nothing] TcRnShadowedName{} -> noHints TcRnDuplicateWarningDecls{} -> noHints TcRnSimplifierTooManyIterations{} -> [SuggestIncreaseSimplifierIterations] TcRnIllegalPatSynDecl{} -> noHints TcRnLinearPatSyn{} -> noHints TcRnEmptyRecordUpdate{} -> noHints TcRnIllegalFieldPunning{} -> [suggestExtension LangExt.NamedFieldPuns] TcRnIllegalWildcardsInRecord{} -> [suggestExtension LangExt.RecordWildCards] TcRnDuplicateFieldName{} -> noHints TcRnIllegalViewPattern{} -> [suggestExtension LangExt.ViewPatterns] TcRnCharLiteralOutOfRange{} -> noHints TcRnIllegalWildcardsInConstructor{} -> noHints TcRnIgnoringAnnotations{} -> noHints TcRnAnnotationInSafeHaskell -> noHints TcRnInvalidTypeApplication{} -> noHints TcRnTagToEnumMissingValArg -> noHints TcRnTagToEnumUnspecifiedResTy{} -> noHints TcRnTagToEnumResTyNotAnEnum{} -> noHints TcRnArrowIfThenElsePredDependsOnResultTy -> noHints TcRnArrowCommandExpected{} -> noHints TcRnIllegalHsBootFileDecl -> noHints TcRnRecursivePatternSynonym{} -> noHints TcRnPartialTypeSigTyVarMismatch{} -> noHints TcRnPartialTypeSigBadQuantifier{} -> noHints TcRnPolymorphicBinderMissingSig{} -> noHints TcRnOverloadedSig{} -> noHints TcRnTupleConstraintInst{} -> noHints TcRnAbstractClassInst{} -> noHints TcRnNoClassInstHead{} -> noHints TcRnUserTypeError{} -> noHints TcRnConstraintInKind{} -> noHints TcRnUnboxedTupleTypeFuncArg{} -> [suggestExtension LangExt.UnboxedTuples] TcRnLinearFuncInKind{} -> noHints TcRnForAllEscapeError{} -> noHints TcRnVDQInTermType{} -> noHints TcRnIllegalEqualConstraints{} -> [suggestAnyExtension [LangExt.GADTs, LangExt.TypeFamilies]] TcRnBadQuantPredHead{} -> noHints TcRnIllegalTupleConstraint{} -> [suggestExtension LangExt.ConstraintKinds] TcRnNonTypeVarArgInConstraint{} -> [suggestExtension LangExt.FlexibleContexts] TcRnIllegalImplicitParam{} -> noHints TcRnIllegalConstraintSynonymOfKind{} -> [suggestExtension LangExt.ConstraintKinds] TcRnIllegalClassInst{} -> noHints TcRnOversaturatedVisibleKindArg{} -> noHints TcRnBadAssociatedType{} -> noHints TcRnForAllRankErr rank _ -> case rank of LimitedRank{} -> [suggestExtension LangExt.RankNTypes] MonoTypeRankZero -> [suggestExtension LangExt.RankNTypes] MonoTypeTyConArg -> [suggestExtension LangExt.ImpredicativeTypes] MonoTypeSynArg -> [suggestExtension LangExt.LiberalTypeSynonyms] MonoTypeConstraint -> [suggestExtension LangExt.QuantifiedConstraints] _ -> noHints TcRnMonomorphicBindings bindings -> case bindings of [] -> noHints (x:xs) -> [SuggestAddTypeSignatures $ NamedBindings (x NE.:| xs)] TcRnOrphanInstance{} -> [SuggestFixOrphanInstance] TcRnFunDepConflict{} -> noHints TcRnDupInstanceDecls{} -> noHints TcRnConflictingFamInstDecls{} -> noHints TcRnFamInstNotInjective rea _ _ -> case rea of InjErrRhsBareTyVar{} -> noHints InjErrRhsCannotBeATypeFam -> noHints InjErrRhsOverlap -> noHints InjErrCannotInferFromRhs _ _ suggestUndInst | YesSuggestUndecidableInstaces <- suggestUndInst -> [suggestExtension LangExt.UndecidableInstances] | otherwise -> noHints TcRnBangOnUnliftedType{} -> noHints TcRnMultipleDefaultDeclarations{} -> noHints TcRnBadDefaultType{} -> noHints TcRnPatSynBundledWithNonDataCon{} -> noHints TcRnPatSynBundledWithWrongType{} -> noHints TcRnDupeModuleExport{} -> noHints TcRnExportedModNotImported{} -> noHints TcRnNullExportedModule{} -> noHints TcRnMissingExportList{} -> noHints TcRnExportHiddenComponents{} -> noHints TcRnDuplicateExport{} -> noHints TcRnExportedParentChildMismatch{} -> noHints TcRnConflictingExports{} -> noHints TcRnAmbiguousField{} -> noHints TcRnMissingFields{} -> noHints TcRnFieldUpdateInvalidType{} -> noHints TcRnNoConstructorHasAllFields{} -> noHints TcRnMixedSelectors{} -> noHints TcRnMissingStrictFields{} -> noHints TcRnNoPossibleParentForFields{} -> noHints TcRnBadOverloadedRecordUpdate{} -> noHints TcRnStaticFormNotClosed{} -> noHints TcRnUselessTypeable -> noHints TcRnDerivingDefaults{} -> [useDerivingStrategies] TcRnNonUnaryTypeclassConstraint{} -> noHints TcRnPartialTypeSignatures suggestParSig _ -> case suggestParSig of YesSuggestPartialTypeSignatures -> let info = text "to use the inferred type" in [suggestExtensionWithInfo info LangExt.PartialTypeSignatures] NoSuggestPartialTypeSignatures -> noHints TcRnCannotDeriveInstance cls _ _ newtype_deriving rea -> deriveInstanceErrReasonHints cls newtype_deriving rea TcRnLazyGADTPattern -> noHints TcRnArrowProcGADTPattern -> noHints TcRnSpecialClassInst {} -> noHints TcRnForallIdentifier {} -> [SuggestRenameForall] TcRnGADTMonoLocalBinds {} -> [suggestAnyExtension [LangExt.GADTs, LangExt.TypeFamilies]] deriveInstanceErrReasonHints :: Class -> UsingGeneralizedNewtypeDeriving -> DeriveInstanceErrReason -> [GhcHint] deriveInstanceErrReasonHints cls newtype_deriving = \case DerivErrNotWellKinded _ _ n_args_to_keep | cls `hasKey` gen1ClassKey && n_args_to_keep >= 0 -> [suggestExtension LangExt.PolyKinds] | otherwise -> noHints DerivErrSafeHaskellGenericInst -> noHints DerivErrDerivingViaWrongKind{} -> noHints DerivErrNoEtaReduce{} -> noHints DerivErrBootFileFound -> noHints DerivErrDataConsNotAllInScope{} -> noHints DerivErrGNDUsedOnData -> noHints DerivErrNullaryClasses -> noHints DerivErrLastArgMustBeApp -> noHints DerivErrNoFamilyInstance{} -> noHints DerivErrNotStockDeriveable deriveAnyClassEnabled | deriveAnyClassEnabled == NoDeriveAnyClassEnabled -> [suggestExtension LangExt.DeriveAnyClass] | otherwise -> noHints DerivErrHasAssociatedDatatypes{} -> noHints DerivErrNewtypeNonDeriveableClass | newtype_deriving == NoGeneralizedNewtypeDeriving -> [useGND] | otherwise -> noHints DerivErrCannotEtaReduceEnough{} | newtype_deriving == NoGeneralizedNewtypeDeriving -> [useGND] | otherwise -> noHints DerivErrOnlyAnyClassDeriveable _ deriveAnyClassEnabled | deriveAnyClassEnabled == NoDeriveAnyClassEnabled -> [suggestExtension LangExt.DeriveAnyClass] | otherwise -> noHints DerivErrNotDeriveable deriveAnyClassEnabled | deriveAnyClassEnabled == NoDeriveAnyClassEnabled -> [suggestExtension LangExt.DeriveAnyClass] | otherwise -> noHints DerivErrNotAClass{} -> noHints DerivErrNoConstructors{} -> let info = text "to enable deriving for empty data types" in [useExtensionInOrderTo info LangExt.EmptyDataDeriving] DerivErrLangExtRequired{} -- This is a slightly weird corner case of GHC: we are failing -- to derive a typeclass instance because a particular 'Extension' -- is not enabled (and so we report in the main error), but here -- we don't want to /repeat/ to enable the extension in the hint. -> noHints DerivErrDunnoHowToDeriveForType{} -> noHints DerivErrMustBeEnumType rep_tc -- We want to suggest GND only if this /is/ a newtype. | newtype_deriving == NoGeneralizedNewtypeDeriving && isNewTyCon rep_tc -> [useGND] | otherwise -> noHints DerivErrMustHaveExactlyOneConstructor{} -> noHints DerivErrMustHaveSomeParameters{} -> noHints DerivErrMustNotHaveClassContext{} -> noHints DerivErrBadConstructor wcard _ -> case wcard of Nothing -> noHints Just YesHasWildcard -> [SuggestFillInWildcardConstraint] Just NoHasWildcard -> [SuggestAddStandaloneDerivation] DerivErrGenerics{} -> noHints DerivErrEnumOrProduct{} -> noHints messageWithInfoDiagnosticMessage :: UnitState -> ErrInfo -> DecoratedSDoc -> DecoratedSDoc messageWithInfoDiagnosticMessage unit_state ErrInfo{..} important = let err_info' = map (pprWithUnitState unit_state) [errInfoContext, errInfoSupplementary] in (mapDecoratedSDoc (pprWithUnitState unit_state) important) `unionDecoratedSDoc` mkDecorated err_info' dodgy_msg :: (Outputable a, Outputable b) => SDoc -> a -> b -> SDoc dodgy_msg kind tc ie = sep [ text "The" <+> kind <+> text "item" <+> quotes (ppr ie) <+> text "suggests that", quotes (ppr tc) <+> text "has (in-scope) constructors or class methods,", text "but it has none" ] dodgy_msg_insert :: forall p . IdP (GhcPass p) -> IE (GhcPass p) dodgy_msg_insert tc = IEThingAll noAnn ii where ii :: LIEWrappedName (IdP (GhcPass p)) ii = noLocA (IEName $ noLocA tc) pprTypeDoesNotHaveFixedRuntimeRep :: Type -> FixedRuntimeRepProvenance -> SDoc pprTypeDoesNotHaveFixedRuntimeRep ty prov = let what = pprFixedRuntimeRepProvenance prov in text "The" <+> what <+> text "does not have a fixed runtime representation:" $$ format_frr_err ty format_frr_err :: Type -- ^ the type which doesn't have a fixed runtime representation -> SDoc format_frr_err ty = (bullet <+> ppr tidy_ty <+> dcolon <+> ppr tidy_ki) where (tidy_env, tidy_ty) = tidyOpenType emptyTidyEnv ty tidy_ki = tidyType tidy_env (tcTypeKind ty) pprField :: (FieldLabelString, TcType) -> SDoc pprField (f,ty) = ppr f <+> dcolon <+> ppr ty pprRecordFieldPart :: RecordFieldPart -> SDoc pprRecordFieldPart = \case RecordFieldConstructor{} -> text "construction" RecordFieldPattern{} -> text "pattern" RecordFieldUpdate -> text "update" pprBindings :: [Name] -> SDoc pprBindings = pprWithCommas (quotes . ppr) injectivityErrorHerald :: SDoc injectivityErrorHerald = text "Type family equation violates the family's injectivity annotation." formatExportItemError :: SDoc -> String -> SDoc formatExportItemError exportedThing reason = hsep [ text "The export item" , quotes exportedThing , text reason ] useDerivingStrategies :: GhcHint useDerivingStrategies = useExtensionInOrderTo (text "to pick a different strategy") LangExt.DerivingStrategies useGND :: GhcHint useGND = let info = text "for GHC's" <+> text "newtype-deriving extension" in suggestExtensionWithInfo info LangExt.GeneralizedNewtypeDeriving cannotMakeDerivedInstanceHerald :: Class -> [Type] -> Maybe (DerivStrategy GhcTc) -> UsingGeneralizedNewtypeDeriving -> Bool -- ^ If False, only prints the why. -> SDoc -> SDoc cannotMakeDerivedInstanceHerald cls cls_args mb_strat newtype_deriving pprHerald why = if pprHerald then sep [(hang (text "Can't make a derived instance of") 2 (quotes (ppr pred) <+> via_mechanism) $$ nest 2 extra) <> colon, nest 2 why] else why where strat_used = isJust mb_strat extra | not strat_used, (newtype_deriving == YesGeneralizedNewtypeDeriving) = text "(even with cunning GeneralizedNewtypeDeriving)" | otherwise = empty pred = mkClassPred cls cls_args via_mechanism | strat_used , Just strat <- mb_strat = text "with the" <+> (derivStrategyName strat) <+> text "strategy" | otherwise = empty badCon :: DataCon -> SDoc -> SDoc badCon con msg = text "Constructor" <+> quotes (ppr con) <+> msg derivErrDiagnosticMessage :: Class -> [Type] -> Maybe (DerivStrategy GhcTc) -> UsingGeneralizedNewtypeDeriving -> Bool -- If True, includes the herald \"can't make a derived..\" -> DeriveInstanceErrReason -> SDoc derivErrDiagnosticMessage cls cls_tys mb_strat newtype_deriving pprHerald = \case DerivErrNotWellKinded tc cls_kind _ -> sep [ hang (text "Cannot derive well-kinded instance of form" <+> quotes (pprClassPred cls cls_tys <+> parens (ppr tc <+> text "..."))) 2 empty , nest 2 (text "Class" <+> quotes (ppr cls) <+> text "expects an argument of kind" <+> quotes (pprKind cls_kind)) ] DerivErrSafeHaskellGenericInst -> text "Generic instances can only be derived in" <+> text "Safe Haskell using the stock strategy." DerivErrDerivingViaWrongKind cls_kind via_ty via_kind -> hang (text "Cannot derive instance via" <+> quotes (pprType via_ty)) 2 (text "Class" <+> quotes (ppr cls) <+> text "expects an argument of kind" <+> quotes (pprKind cls_kind) <> char ',' $+$ text "but" <+> quotes (pprType via_ty) <+> text "has kind" <+> quotes (pprKind via_kind)) DerivErrNoEtaReduce inst_ty -> sep [text "Cannot eta-reduce to an instance of form", nest 2 (text "instance (...) =>" <+> pprClassPred cls (cls_tys ++ [inst_ty]))] DerivErrBootFileFound -> cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald (text "Cannot derive instances in hs-boot files" $+$ text "Write an instance declaration instead") DerivErrDataConsNotAllInScope tc -> cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald (hang (text "The data constructors of" <+> quotes (ppr tc) <+> text "are not all in scope") 2 (text "so you cannot derive an instance for it")) DerivErrGNDUsedOnData -> cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald (text "GeneralizedNewtypeDeriving cannot be used on non-newtypes") DerivErrNullaryClasses -> cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald (text "Cannot derive instances for nullary classes") DerivErrLastArgMustBeApp -> cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald ( text "The last argument of the instance must be a" <+> text "data or newtype application") DerivErrNoFamilyInstance tc tc_args -> cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald (text "No family instance for" <+> quotes (pprTypeApp tc tc_args)) DerivErrNotStockDeriveable _ -> cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald (quotes (ppr cls) <+> text "is not a stock derivable class (Eq, Show, etc.)") DerivErrHasAssociatedDatatypes hasAdfs at_last_cls_tv_in_kinds at_without_last_cls_tv -> cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald $ vcat [ ppWhen (hasAdfs == YesHasAdfs) adfs_msg , case at_without_last_cls_tv of YesAssociatedTyNotParamOverLastTyVar tc -> at_without_last_cls_tv_msg tc NoAssociatedTyNotParamOverLastTyVar -> empty , case at_last_cls_tv_in_kinds of YesAssocTyLastVarInKind tc -> at_last_cls_tv_in_kinds_msg tc NoAssocTyLastVarInKind -> empty ] where adfs_msg = text "the class has associated data types" at_without_last_cls_tv_msg at_tc = hang (text "the associated type" <+> quotes (ppr at_tc) <+> text "is not parameterized over the last type variable") 2 (text "of the class" <+> quotes (ppr cls)) at_last_cls_tv_in_kinds_msg at_tc = hang (text "the associated type" <+> quotes (ppr at_tc) <+> text "contains the last type variable") 2 (text "of the class" <+> quotes (ppr cls) <+> text "in a kind, which is not (yet) allowed") DerivErrNewtypeNonDeriveableClass -> derivErrDiagnosticMessage cls cls_tys mb_strat newtype_deriving pprHerald (DerivErrNotStockDeriveable NoDeriveAnyClassEnabled) DerivErrCannotEtaReduceEnough eta_ok -> let cant_derive_err = ppUnless eta_ok eta_msg eta_msg = text "cannot eta-reduce the representation type enough" in cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald cant_derive_err DerivErrOnlyAnyClassDeriveable tc _ -> cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald (quotes (ppr tc) <+> text "is a type class," <+> text "and can only have a derived instance" $+$ text "if DeriveAnyClass is enabled") DerivErrNotDeriveable _ -> cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald empty DerivErrNotAClass predType -> cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald (quotes (ppr predType) <+> text "is not a class") DerivErrNoConstructors rep_tc -> cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald (quotes (pprSourceTyCon rep_tc) <+> text "must have at least one data constructor") DerivErrLangExtRequired ext -> cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald (text "You need " <> ppr ext <+> text "to derive an instance for this class") DerivErrDunnoHowToDeriveForType ty -> cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald (hang (text "Don't know how to derive" <+> quotes (ppr cls)) 2 (text "for type" <+> quotes (ppr ty))) DerivErrMustBeEnumType rep_tc -> cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald (sep [ quotes (pprSourceTyCon rep_tc) <+> text "must be an enumeration type" , text "(an enumeration consists of one or more nullary, non-GADT constructors)" ]) DerivErrMustHaveExactlyOneConstructor rep_tc -> cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald (quotes (pprSourceTyCon rep_tc) <+> text "must have precisely one constructor") DerivErrMustHaveSomeParameters rep_tc -> cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald (text "Data type" <+> quotes (ppr rep_tc) <+> text "must have some type parameters") DerivErrMustNotHaveClassContext rep_tc bad_stupid_theta -> cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald (text "Data type" <+> quotes (ppr rep_tc) <+> text "must not have a class context:" <+> pprTheta bad_stupid_theta) DerivErrBadConstructor _ reasons -> let why = vcat $ map renderReason reasons in cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald why where renderReason = \case DerivErrBadConExistential con -> badCon con $ text "must be truly polymorphic in the last argument of the data type" DerivErrBadConCovariant con -> badCon con $ text "must not use the type variable in a function argument" DerivErrBadConFunTypes con -> badCon con $ text "must not contain function types" DerivErrBadConWrongArg con -> badCon con $ text "must use the type variable only as the last argument of a data type" DerivErrBadConIsGADT con -> badCon con $ text "is a GADT" DerivErrBadConHasExistentials con -> badCon con $ text "has existential type variables in its type" DerivErrBadConHasConstraints con -> badCon con $ text "has constraints in its type" DerivErrBadConHasHigherRankType con -> badCon con $ text "has a higher-rank type" DerivErrGenerics reasons -> let why = vcat $ map renderReason reasons in cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald why where renderReason = \case DerivErrGenericsMustNotHaveDatatypeContext tc_name -> ppr tc_name <+> text "must not have a datatype context" DerivErrGenericsMustNotHaveExoticArgs dc -> ppr dc <+> text "must not have exotic unlifted or polymorphic arguments" DerivErrGenericsMustBeVanillaDataCon dc -> ppr dc <+> text "must be a vanilla data constructor" DerivErrGenericsMustHaveSomeTypeParams rep_tc -> text "Data type" <+> quotes (ppr rep_tc) <+> text "must have some type parameters" DerivErrGenericsMustNotHaveExistentials con -> badCon con $ text "must not have existential arguments" DerivErrGenericsWrongArgKind con -> badCon con $ text "applies a type to an argument involving the last parameter" $$ text "but the applied type is not of kind * -> *" DerivErrEnumOrProduct this that -> let ppr1 = derivErrDiagnosticMessage cls cls_tys mb_strat newtype_deriving False this ppr2 = derivErrDiagnosticMessage cls cls_tys mb_strat newtype_deriving False that in cannotMakeDerivedInstanceHerald cls cls_tys mb_strat newtype_deriving pprHerald (ppr1 $$ text " or" $$ ppr2)