ghc-lib-parser-0.20211101: compiler/GHC/Tc/Errors/Ppr.hs
{-# 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
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
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
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)