ghc-9.12.3: GHC/Tc/Errors/Ppr.hs
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE MonadComprehensions #-}
{-# LANGUAGE NamedFieldPuns #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE ViewPatterns #-}
{-# LANGUAGE TypeApplications #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE OverloadedStrings #-}
{-# OPTIONS_GHC -fno-warn-orphans #-} -- instance Diagnostic TcRnMessage
{-# LANGUAGE InstanceSigs #-}
module GHC.Tc.Errors.Ppr
( pprTypeDoesNotHaveFixedRuntimeRep
, pprScopeError
--
, tidySkolemInfo
, tidySkolemInfoAnon
--
, pprHsDocContext
, inHsDocContext
, TcRnMessageOpts(..)
, pprTyThingUsedWrong
, pprUntouchableVariable
--
, mismatchMsg_ExpectedActuals
-- | Useful when overriding message printing.
, messageWithInfoDiagnosticMessage
, messageWithHsDocContext
)
where
import GHC.Prelude
import qualified GHC.Boot.TH.Syntax as TH
-- In stage1: import "ghc-boot-th-next" qualified GHC.Boot.TH.Syntax as TH
-- In stage2: import "ghc-boot-th" qualified GHC.Boot.TH.Syntax as TH
-- which is a rexport of
-- import "ghc-internal" qualified GHC.Internal.TH.Syntax as TH
import qualified GHC.Boot.TH.Ppr as TH
import GHC.Builtin.Names
import GHC.Builtin.Types ( boxedRepDataConTyCon, tYPETyCon, filterCTuple, pretendNameIsInScope )
import GHC.Types.Name.Reader
import GHC.Unit.Module.ModIface
import GHC.Unit.Module.Warnings
import GHC.Core.Coercion
import GHC.Core.Unify ( tcMatchTys )
import GHC.Core.TyCon
import GHC.Core.Class
import GHC.Core.DataCon
import GHC.Core.Coercion.Axiom (CoAxBranch, coAxiomTyCon, coAxiomSingleBranch)
import GHC.Core.ConLike
import GHC.Core.FamInstEnv ( FamInst(..), famInstAxiom, pprFamInst )
import GHC.Core.InstEnv
import GHC.Core.TyCo.Rep (Type(..))
import GHC.Core.TyCo.Ppr (pprWithInvisibleBitsWhen, pprSourceTyCon,
pprTyVars, pprWithTYPE, pprTyVar, pprTidiedType, pprForAll)
import GHC.Core.PatSyn ( patSynName, pprPatSynType )
import GHC.Core.Predicate
import GHC.Core.Type
import GHC.Core.FVs( orphNamesOfTypes )
import GHC.CoreToIface
import GHC.Driver.Flags
import GHC.Driver.Backend
import GHC.Hs
import GHC.Tc.Errors.Types
import GHC.Tc.Types.BasicTypes
import GHC.Tc.Types.Constraint
import GHC.Tc.Types.Origin hiding ( Position(..) )
import GHC.Tc.Types.CtLoc
import GHC.Tc.Types.Rank (Rank(..))
import GHC.Tc.Types.TH
import GHC.Tc.Utils.TcType
import GHC.Types.DefaultEnv (ClassDefaults(ClassDefaults, cd_types, cd_module))
import GHC.Types.Error
import GHC.Types.Error.Codes
import GHC.Types.Hint
import GHC.Types.Hint.Ppr () -- Outputable GhcHint
import GHC.Types.Basic
import GHC.Types.Id
import GHC.Types.Id.Info ( RecSelParent(..) )
import GHC.Types.Name
import GHC.Types.Name.Env
import GHC.Types.Name.Set
import GHC.Types.SourceFile
import GHC.Types.SrcLoc
import GHC.Types.TyThing
import GHC.Types.TyThing.Ppr ( pprTyThingInContext )
import GHC.Types.Unique.Set ( nonDetEltsUniqSet )
import GHC.Types.Var
import GHC.Types.Var.Set
import GHC.Types.Var.Env
import GHC.Types.Fixity (defaultFixity)
import GHC.Iface.Errors.Types
import GHC.Iface.Errors.Ppr
import GHC.Iface.Syntax
import GHC.Unit.State
import GHC.Unit.Module
import GHC.Data.Bag
import GHC.Data.FastString
import GHC.Data.List.SetOps ( nubOrdBy )
import GHC.Data.Maybe
import GHC.Data.Pair
import GHC.Settings.Constants (mAX_TUPLE_SIZE, mAX_CTUPLE_SIZE)
import GHC.Utils.Misc
import GHC.Utils.Outputable
import GHC.Utils.Panic
import qualified GHC.LanguageExtensions as LangExt
import GHC.Data.BooleanFormula (pprBooleanFormulaNice)
import Data.List.NonEmpty (NonEmpty(..))
import qualified Data.List.NonEmpty as NE
import Data.Foldable ( fold )
import Data.Function (on)
import Data.List ( groupBy, sortBy, tails
, partition, unfoldr )
import Data.Ord ( comparing )
import Data.Bifunctor
defaultTcRnMessageOpts :: TcRnMessageOpts
defaultTcRnMessageOpts = TcRnMessageOpts { tcOptsShowContext = True
, tcOptsIfaceOpts = defaultDiagnosticOpts @IfaceMessage }
instance HasDefaultDiagnosticOpts TcRnMessageOpts where
defaultOpts = defaultTcRnMessageOpts
instance Diagnostic TcRnMessage where
type DiagnosticOpts TcRnMessage = TcRnMessageOpts
diagnosticMessage opts = \case
TcRnUnknownMessage (UnknownDiagnostic f m)
-> diagnosticMessage (f opts) m
TcRnMessageWithInfo unit_state msg_with_info
-> case msg_with_info of
TcRnMessageDetailed err_info msg
-> messageWithInfoDiagnosticMessage unit_state err_info
(tcOptsShowContext opts)
(diagnosticMessage opts msg)
TcRnWithHsDocContext ctxt msg
-> messageWithHsDocContext opts ctxt (diagnosticMessage opts msg)
TcRnSolverReport msg _
-> mkSimpleDecorated $ pprSolverReportWithCtxt msg
TcRnSolverDepthError ty depth -> mkSimpleDecorated msg
where
msg =
vcat [ text "Reduction stack overflow; size =" <+> ppr depth
, hang (text "When simplifying the following type:")
2 (ppr ty) ]
TcRnRedundantConstraints redundants (info, show_info)
-> mkSimpleDecorated $
text "Redundant constraint" <> plural redundants <> colon
<+> pprEvVarTheta redundants
$$ if show_info then text "In" <+> ppr info else empty
TcRnInaccessibleCode implic contra
-> mkSimpleDecorated $
hang (text "Inaccessible code in")
2 (ppr (ic_info implic))
$$ pprSolverReportWithCtxt contra
TcRnInaccessibleCoAxBranch fam_tc cur_branch
-> mkSimpleDecorated $
text "Type family instance equation is overlapped:" $$
nest 2 (pprCoAxBranchUser fam_tc cur_branch)
TcRnTypeDoesNotHaveFixedRuntimeRep ty prov (ErrInfo extra supplementary)
-> mkDecorated [pprTypeDoesNotHaveFixedRuntimeRep ty prov, extra, supplementary]
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 (DodgyImportsEmptyParent gre)
-> mkDecorated [dodgy_msg (text "import") gre (dodgy_msg_insert gre)]
TcRnDodgyImports (DodgyImportsHiding reason)
-> mkSimpleDecorated $
pprImportLookup reason
TcRnDodgyExports gre
-> mkDecorated [dodgy_msg (text "export") gre (dodgy_msg_insert gre)]
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)]
TcRnInvalidWarningCategory cat
-> mkSimpleDecorated $
vcat [text "Warning category" <+> quotes (ppr cat) <+> text "is not valid",
text "(user-defined category names must begin with" <+> quotes (text "x-"),
text "and contain only letters, numbers, apostrophes and dashes)" ]
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
TcRnIllegalWildcardInType mb_name bad
-> mkSimpleDecorated $ case bad of
WildcardNotLastInConstraint ->
hang notAllowed 2 constraint_hint_msg
ExtraConstraintWildcardNotAllowed allow_sole ->
case allow_sole of
SoleExtraConstraintWildcardNotAllowed ->
notAllowed
SoleExtraConstraintWildcardAllowed ->
hang notAllowed 2 sole_msg
WildcardsNotAllowedAtAll ->
notAllowed
WildcardBndrInForallTelescope ->
notAllowed
WildcardBndrInTyFamResultVar ->
notAllowed
where
notAllowed, what, wildcard, how :: SDoc
notAllowed = what <+> quotes wildcard <+> how
wildcard = case mb_name of
Nothing -> pprAnonWildCard
Just name -> ppr name
what
| Just _ <- mb_name
= text "Named wildcard"
| ExtraConstraintWildcardNotAllowed {} <- bad
= text "Extra-constraint wildcard"
| WildcardBndrInForallTelescope {} <- bad
= text "Wildcard binder"
| WildcardBndrInTyFamResultVar {} <- bad
= text "Wildcard binder"
| otherwise
= text "Wildcard"
how = case bad of
WildcardNotLastInConstraint
-> text "not allowed in a constraint"
WildcardBndrInForallTelescope
-> text "not allowed in a forall telescope"
WildcardBndrInTyFamResultVar
-> text "not allowed in a type family result"
_ -> text "not allowed"
constraint_hint_msg :: SDoc
constraint_hint_msg
| Just _ <- mb_name
= vcat [ text "Extra-constraint wildcards must be anonymous"
, nest 2 (text "e.g f :: (Eq a, _) => blah") ]
| otherwise
= vcat [ text "except as the last top-level constraint of a type signature"
, nest 2 (text "e.g f :: (Eq a, _) => blah") ]
sole_msg :: SDoc
sole_msg =
vcat [ text "except as the sole constraint"
, nest 2 (text "e.g., deriving instance _ => Eq (Foo a)") ]
TcRnIllegalNamedWildcardInTypeArgument rdr
-> mkSimpleDecorated $
hang (text "Illegal named wildcard in a required type argument:")
2 (quotes (ppr rdr))
TcRnIllegalImplicitTyVarInTypeArgument rdr
-> mkSimpleDecorated $
hang (text "Illegal implicitly quantified type variable in a required type argument:")
2 (quotes (ppr rdr))
TcRnDuplicateFieldName fld_part dups
-> mkSimpleDecorated $
hsep [ text "Duplicate field name"
, quotes (ppr (rdrNameOcc $ 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 "Record wildcards may not be used for constructors with unlabelled fields.")
, nest 2 (text "Possible fix: Remove the `{..}' and add a match for each field of the constructor.")
]
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")
TcRnTagToEnumResTyTypeData ty
-> mkSimpleDecorated $
hang (text "Bad call to tagToEnum# at type" <+> ppr ty)
2 (text "Result type cannot be headed by a `type data` type")
TcRnArrowIfThenElsePredDependsOnResultTy
-> mkSimpleDecorated $
text "Predicate type of `ifThenElse' depends on result type"
TcRnIllegalHsBootOrSigDecl boot_or_sig decls
-> mkSimpleDecorated $
text "Illegal" <+> what <+> text "in" <+> whr <> dot
where
what = case decls of
BootBindsPs {} -> text "binding"
BootBindsRn {} -> text "binding"
BootInstanceSigs {} -> text "instance body"
BootFamInst {} -> text "family instance"
BootSpliceDecls {} -> text "splice"
BootForeignDecls {} -> text "foreign declaration"
BootDefaultDecls {} -> text "default declaration"
BootRuleDecls {} -> text "RULE pragma"
whr = case boot_or_sig of
HsBoot -> text "an hs-boot file"
Hsig -> text "a backpack signature file"
TcRnBootMismatch boot_or_sig err ->
mkSimpleDecorated $ pprBootMismatch boot_or_sig err
TcRnRecursivePatternSynonym binds
-> mkSimpleDecorated $
hang (text "Recursive pattern synonym definition with following bindings:")
2 (vcat $ map pprLBind binds)
where
pprLoc loc = parens (text "defined at" <+> ppr loc)
pprLBind :: CollectPass GhcRn => GenLocated (EpAnn 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 m_unif_ty hs_ty
-> mkSimpleDecorated $
hang (text "Can't quantify over" <+> quotes (ppr n))
2 (vcat [ hang (text "bound by the partial type signature:")
2 (ppr fn_name <+> dcolon <+> ppr hs_ty)
, extra ])
where
extra | Just rhs_ty <- m_unif_ty
= sep [ quotes (ppr n), text "should really be", quotes (ppr rhs_ty) ]
| otherwise
= empty
TcRnMissingSignature what _ ->
mkSimpleDecorated $
case what of
MissingPatSynSig p ->
hang (text "Pattern synonym with no type signature:")
2 (text "pattern" <+> pprPrefixName (patSynName p) <+> dcolon <+> pprPatSynType p)
MissingTopLevelBindingSig name ty ->
hang (text "Top-level binding with no type signature:")
2 (pprPrefixName name <+> dcolon <+> pprSigmaType ty)
MissingTyConKindSig tc cusks_enabled ->
hang msg
2 (text "type" <+> pprPrefixName (tyConName tc) <+> dcolon <+> pprKind (tyConKind tc))
where
msg | cusks_enabled
= text "Top-level type constructor with no standalone kind signature or CUSK:"
| otherwise
= text "Top-level type constructor with no standalone kind signature:"
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"
TcRnUserTypeError ty
-> mkSimpleDecorated (pprUserTypeErrorTy ty)
TcRnConstraintInKind ty
-> mkSimpleDecorated $
text "Illegal constraint in a kind:" <+> pprType ty
TcRnUnboxedTupleOrSumTypeFuncArg tuple_or_sum ty
-> mkSimpleDecorated $
sep [ text "Illegal unboxed" <+> what <+> text "type as function argument:"
, pprType ty ]
where
what = case tuple_or_sum of
UnboxedTupleType -> text "tuple"
UnboxedSumType -> text "sum"
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)) ]
TcRnSimplifiableConstraint pred what
-> mkSimpleDecorated $ vcat
[ hang (text "The constraint" <+> quotes (pprType pred) <+> text "matches")
2 (ppr what)
, hang (text "This makes type inference for inner bindings fragile;")
2 (text "either use MonoLocalBinds, or simplify it using the instance") ]
TcRnArityMismatch thing thing_arity nb_args
-> mkSimpleDecorated $
hsep [ text "The" <+> what, quotes (ppr $ getName thing), text "should have"
, n_arguments <> comma, text "but has been given"
, if nb_args == 0 then text "none" else int nb_args
]
where
what = case thing of
ATyCon tc -> ppr (tyConFlavour tc)
_ -> text (tyThingCategory thing)
n_arguments | thing_arity == 0 = text "no arguments"
| thing_arity == 1 = text "1 argument"
| True = hsep [int thing_arity, text "arguments"]
TcRnIllegalInstance reason ->
mkSimpleDecorated $ pprIllegalInstance reason
TcRnVDQInTermType mb_ty
-> mkSimpleDecorated $
case mb_ty of
Nothing -> main_msg
Just ty -> hang (main_msg <> char ':') 2 (pprType ty)
where
main_msg =
text "Illegal visible, dependent quantification" <+>
text "in the type of a term"
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)
TcRnOversaturatedVisibleKindArg ty
-> mkSimpleDecorated $
text "Illegal oversaturated visible kind argument:" <+>
quotes (char '@' <> pprParendType ty)
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 (Left cls_inst)
-> mkSimpleDecorated $
hang (text "Orphan class instance:")
2 (pprInstanceHdr cls_inst)
TcRnOrphanInstance (Right fam_inst)
-> mkSimpleDecorated $
hang (text "Orphan family instance:")
2 (pprFamInst fam_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 $ pprWithInvisibleBitsWhen 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)
TcRnLazyBangOnUnliftedType ty
-> mkSimpleDecorated $
text "Lazy flag has no effect on unlifted type" <+> quotes (ppr ty)
TcRnMultipleDefaultDeclarations cls dup_things
-> mkSimpleDecorated $
hang (text "Multiple default declarations for class" <+> quotes (ppr cls))
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) (NE.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"
$$ text "Couldn't match expected type of"
<+> quotes (ppr expected_res_ty)
<+> text "with actual type of"
<+> quotes (ppr res_ty)
TcRnDupeModuleExport mod
-> mkSimpleDecorated $
hsep [ text "Duplicate"
, quotes (text "Module" <+> ppr mod)
, text "in export list" ]
TcRnExportedModNotImported mod
-> mkSimpleDecorated
$ formatExportItemError
(text "module" <+> ppr mod)
"is not imported"
TcRnNullExportedModule mod
-> mkSimpleDecorated
$ formatExportItemError
(text "module" <+> ppr mod)
"exports nothing"
TcRnMissingExportList mod
-> mkSimpleDecorated
$ formatExportItemError
(text "module" <+> ppr mod)
"is missing an export list"
TcRnExportHiddenComponents export_item
-> mkSimpleDecorated
$ formatExportItemError
(ppr export_item)
"attempts to export constructors or class methods that are not visible here"
TcRnExportHiddenDefault export_item
-> mkSimpleDecorated
$ formatExportItemError
(ppr export_item)
"attempts to export a default class declaration that is not visible here"
TcRnDuplicateExport gre ie1 ie2
-> mkSimpleDecorated $
hsep [ quotes (ppr $ greName gre)
, text "is exported by", quotes (ppr ie1)
, text "and", quotes (ppr ie2) ]
TcRnExportedParentChildMismatch parent_name ty_thing child parent_names
-> mkSimpleDecorated $
text "The type constructor" <+> quotes (ppr parent_name)
<+> text "is not the parent of the" <+> text what_is
<+> quotes thing <> char '.'
$$ 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 $ nameOccName child
parents = map ppr parent_names
TcRnConflictingExports occ child_gre1 ie1 child_gre2 ie2
-> mkSimpleDecorated $
vcat [ text "Conflicting exports for" <+> quotes (ppr occ) <> colon
, ppr_export child_gre1 ie1
, ppr_export child_gre2 ie2
]
where
ppr_export gre ie =
nest 3 $
hang (quotes (ppr ie) <+> text "exports" <+> quotes (ppr $ greName gre))
2 (pprNameProvenance gre)
TcRnDuplicateFieldExport (gre, ie1) gres_ies ->
mkSimpleDecorated $
vcat ( hsep [ text "Duplicate record field"
, quotes (ppr $ greOccName gre)
, text "in export list" <> colon ]
: map ppr_export ((gre,ie1) : NE.toList gres_ies)
)
where
ppr_export (gre,ie) =
nest 3 $
hang (sep [ quotes (ppr ie) <+> text "exports the field" <+> quotes (ppr $ greName gre)
, text "belonging to the constructor" <> plural fld_cons <+> pprQuotedList fld_cons ])
2 (pprNameProvenance gre)
where
fld_cons :: [ConLikeName]
fld_cons = nonDetEltsUniqSet $ recFieldCons $ fieldGREInfo gre
TcRnAmbiguousFieldInUpdate (gre1, gre2, gres)
-> mkSimpleDecorated $
vcat [ text "Ambiguous record field" <+> fld <> dot
, hang (text "It could refer to any of the following:")
2 $ vcat (map pprSugg (gre1 : gre2 : gres))
]
where
fld = quotes $ ppr (occNameFS $ greOccName gre1)
pprSugg gre = vcat [ bullet <+> pprGRE gre <> comma
, nest 2 (pprNameProvenance gre) ]
pprGRE gre = case greInfo gre of
IAmRecField {}
-> let parent = par_is $ greParent gre
in text "record field" <+> fld <+> text "of" <+> quotes (ppr parent)
_ -> text "variable" <+> fld
TcRnAmbiguousRecordUpdate _rupd tc
-> mkSimpleDecorated $
vcat [ text "Ambiguous record update with parent" <+> what <> dot
, hsep [ text "This type-directed disambiguation mechanism"
, text "will not be supported by -XDuplicateRecordFields in future releases of GHC." ]
, text "Consider disambiguating using module qualification instead."
]
where
what :: SDoc
what = text "type constructor" <+> quotes (ppr $ RecSelData tc)
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 ])
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
TcRnBadRecordUpdate upd_flds reason
-> case reason of
NoConstructorHasAllFields { conflictingFields = conflicts }
| [fld] <- conflicts
-> mkSimpleDecorated $
vcat [ header
, text "No constructor in scope has the field" <+> quotes (ppr fld) ]
| otherwise
->
mkSimpleDecorated $
vcat [ header
, hang (text "No constructor in scope has all of the following fields:")
2 (pprQuotedList conflicts) ]
where
header :: SDoc
header = text "Invalid record update."
MultiplePossibleParents (par1, par2, pars) ->
mkSimpleDecorated $
vcat [ hang (text "Ambiguous record update with field" <> plural upd_flds)
2 ppr_flds
, hang (thisOrThese upd_flds <+> text "field" <> plural upd_flds <+> what_parent)
2 (quotedListWithAnd (map ppr (par1:par2:pars))) ]
where
ppr_flds, what_parent, which :: SDoc
ppr_flds = quotedListWithAnd $ map ppr upd_flds
what_parent = case par1 of
RecSelData {} -> text "appear" <> singular upd_flds
<+> text "in" <+> which <+> text "datatypes"
RecSelPatSyn {} -> isOrAre upd_flds <+> text "associated with"
<+> which <+> text "pattern synonyms"
which = case pars of
[] -> text "both"
_ -> text "all of the"
InvalidTyConParent tc pars ->
mkSimpleDecorated $
vcat [ hang (text "No data constructor of" <+> what $$ text "has all of the fields:")
2 (pprQuotedList upd_flds)
, pat_syn_msg ]
where
what = text "type constructor" <+> quotes (ppr (RecSelData tc))
pat_syn_msg
| any (\case { RecSelPatSyn {} -> True; _ -> False}) pars
= note "Type-directed disambiguation is not supported for pattern synonym record fields"
| otherwise
= empty
TcRnStaticFormNotClosed name reason
-> mkSimpleDecorated $
quotes (ppr name)
<+> text "is used in a static form but it is not closed"
<+> text "because it"
$$ sep (causes reason)
where
causes :: NotClosedReason -> [SDoc]
causes NotLetBoundReason = [text "is not let-bound."]
causes (NotTypeClosed vs) =
[ text "has a non-closed type because it contains the"
, text "type variables:" <+>
pprVarSet vs (hsep . punctuate comma . map (quotes . ppr))
]
causes (NotClosed n reason) =
let msg = text "uses" <+> quotes (ppr n) <+> text "which"
in case reason of
NotClosed _ _ -> msg : causes reason
_ -> let (xs0, xs1) = splitAt 1 $ causes reason
in fmap (msg <+>) xs0 ++ xs1
TcRnUselessTypeable
-> mkSimpleDecorated $
text "Deriving" <+> quotes (ppr typeableClassName) <+>
text "has no effect: all types now auto-derive Typeable"
TcRnDerivingDefaults cls
-> mkSimpleDecorated $ sep
[ text "Both DeriveAnyClass and"
<+> text "GeneralizedNewtypeDeriving are enabled"
, text "Defaulting to the DeriveAnyClass strategy"
<+> text "for instantiating" <+> ppr cls
]
TcRnNonUnaryTypeclassConstraint ctxt ct
-> mkSimpleDecorated $
quotes (ppr ct)
<+> text "is not a unary constraint, as expected by"
<+> pprUserTypeCtxt ctxt
TcRnPartialTypeSignatures _ theta
-> mkSimpleDecorated $
text "Found type wildcard" <+> quotes (char '_')
<+> text "standing for" <+> quotes (pprTheta theta)
TcRnCannotDeriveInstance cls cls_tys mb_strat newtype_deriving reason
-> mkSimpleDecorated $
derivErrDiagnosticMessage cls cls_tys mb_strat newtype_deriving True reason
TcRnLookupInstance cls tys reason
-> mkSimpleDecorated $
text "Couldn't match instance:" <+>
lookupInstanceErrDiagnosticMessage cls tys reason
TcRnLazyGADTPattern
-> mkSimpleDecorated $
hang (text "An existential or GADT data constructor cannot be used")
2 (text "inside a lazy (~) pattern")
TcRnArrowProcGADTPattern
-> mkSimpleDecorated $
text "Proc patterns cannot use existential or GADT data constructors"
TcRnTypeEqualityOutOfScope
-> mkDecorated
[ text "The" <+> quotes (text "~") <+> text "operator is out of scope." $$
text "Assuming it to stand for an equality constraint."
, note $ quotes "~" <+> "used to be built-in syntax but now is a regular type operator" $$
"exported from Data.Type.Equality and Prelude." $$
"If you are using a custom Prelude, consider re-exporting it"
, text "This will become an error in a future GHC release." ]
TcRnTypeEqualityRequiresOperators
-> mkSimpleDecorated $
fsep [ text "The use of" <+> quotes (text "~")
<+> text "without TypeOperators",
text "will become an error in a future GHC release." ]
TcRnIllegalTypeOperator overall_ty op
-> mkSimpleDecorated $
text "Illegal operator" <+> quotes (ppr op) <+>
text "in type" <+> quotes (ppr overall_ty)
TcRnIllegalTypeOperatorDecl name
-> mkSimpleDecorated $
text "Illegal declaration of a type or class operator" <+> quotes (ppr name)
TcRnGADTMonoLocalBinds
-> mkSimpleDecorated $
fsep [ text "Pattern matching on GADTs without MonoLocalBinds"
, text "is fragile." ]
TcRnIncorrectNameSpace name _
-> mkSimpleDecorated $
text "The" <+> what <+> text "does not live in" <+> other_ns
where
-- the other (opposite) namespace
other_ns | isValNameSpace ns = text "the type-level namespace"
| otherwise = text "the term-level namespace"
ns = nameNameSpace name
what = pprNameSpace ns <+> quotes (ppr name)
TcRnNotInScope err name imp_errs _
-> mkSimpleDecorated $
pprScopeError name err $$ vcat (map ppr imp_errs)
TcRnTermNameInType name _
-> mkSimpleDecorated $
quotes (ppr name) <+>
(text "is a term-level binding") $+$
(text " and can not be used at the type level.")
TcRnUntickedPromotedThing thing
-> mkSimpleDecorated $
text "Unticked promoted" <+> what
where
what :: SDoc
what = case thing of
UntickedExplicitList -> text "list" <> dot
UntickedConstructor fixity nm ->
let con = pprUntickedConstructor fixity nm
bare_sym = isBareSymbol fixity nm
in text "constructor:" <+> con <> if bare_sym then empty else dot
TcRnIllegalBuiltinSyntax what rdr_name
-> mkSimpleDecorated $
hsep [text "Illegal", what, text "of built-in syntax:", ppr rdr_name]
TcRnWarnDefaulting tidy_wanteds tidy_tv default_ty
-> mkSimpleDecorated $
hang (hsep $ [ text "Defaulting" ]
++
(case tidy_tv of
Nothing -> []
Just tv -> [text "the type variable"
, quotes (ppr tv)])
++
[ text "to type"
, quotes (ppr default_ty)
, text "in the following constraint" <> plural tidy_wanteds ])
2
(pprWithArising tidy_wanteds)
TcRnWarnClashingDefaultImports cls Nothing imports
-> mkSimpleDecorated $
hang (text "Clashing imported defaults for class" <+> quotes (ppr cls) <> colon)
2 (vcat $ defaultTypesAndImport <$> NE.toList imports)
TcRnWarnClashingDefaultImports cls (Just local) imports
-> mkSimpleDecorated $
sep [ hang (text "Imported defaults for class" <+> quotes (ppr cls) <> colon)
2 (vcat $ defaultTypesAndImport <$> NE.toList imports)
, hang (text "are not subsumed by the local `default` declaration")
2 (parens $ pprWithCommas ppr local)
]
TcRnForeignImportPrimExtNotSet _decl
-> mkSimpleDecorated $
text "`foreign import prim' requires GHCForeignImportPrim."
TcRnForeignImportPrimSafeAnn _decl
-> mkSimpleDecorated $
text "The safe/unsafe annotation should not be used with `foreign import prim'."
TcRnForeignFunctionImportAsValue _decl
-> mkSimpleDecorated $
text "`value' imports cannot have function types"
TcRnFunPtrImportWithoutAmpersand _decl
-> mkSimpleDecorated $
text "possible missing & in foreign import of FunPtr"
TcRnIllegalForeignDeclBackend _decl _backend expectedBknds
-> mkSimpleDecorated $
fsep (text "Illegal foreign declaration: requires one of these back ends:" :
commafyWith (text "or") (map (text . backendDescription) expectedBknds))
TcRnUnsupportedCallConv _decl unsupportedCC
-> mkSimpleDecorated $
case unsupportedCC of
StdCallConvUnsupported ->
text "the 'stdcall' calling convention is unsupported on this platform,"
$$ text "treating as ccall"
PrimCallConvUnsupported ->
text "The `prim' calling convention can only be used with `foreign import'"
JavaScriptCallConvUnsupported ->
text "The `javascript' calling convention is unsupported on this platform"
TcRnIllegalForeignType mArgOrResult reason
-> mkSimpleDecorated $ hang msg 2 extra
where
arg_or_res = case mArgOrResult of
Nothing -> empty
Just Arg -> text "argument"
Just Result -> text "result"
msg = hsep [ text "Unacceptable", arg_or_res
, text "type in foreign declaration:"]
extra =
case reason of
TypeCannotBeMarshaled ty why ->
let innerMsg = quotes (ppr ty) <+> text "cannot be marshalled in a foreign call"
in case why of
NotADataType ->
quotes (ppr ty) <+> text "is not a data type"
NewtypeDataConNotInScope _ [] ->
hang innerMsg 2 $ text "because its data constructor is not in scope"
NewtypeDataConNotInScope tc _ ->
hang innerMsg 2 $
text "because the data constructor for"
<+> quotes (ppr tc) <+> text "is not in scope"
UnliftedFFITypesNeeded ->
innerMsg $$ text "UnliftedFFITypes is required to marshal unlifted types"
NotABoxedMarshalableTyCon -> innerMsg
ForeignLabelNotAPtr ->
innerMsg $$ text "A foreign-imported address (via &foo) must have type (Ptr a) or (FunPtr a)"
NotSimpleUnliftedType ->
innerMsg $$ text "foreign import prim only accepts simple unlifted types"
NotBoxedKindAny ->
text "Expected kind" <+> quotes (text "Type") <+> text "or" <+> quotes (text "UnliftedType") <> comma $$
text "but" <+> quotes (ppr ty) <+> text "has kind" <+> quotes (ppr (typeKind ty))
ForeignDynNotPtr expected ty ->
vcat [ text "Expected: Ptr/FunPtr" <+> pprParendType expected <> comma, text " Actual:" <+> ppr ty ]
SafeHaskellMustBeInIO ->
text "Safe Haskell is on, all FFI imports must be in the IO monad"
IOResultExpected ->
text "IO result type expected"
UnexpectedNestedForall ->
text "Unexpected nested forall"
LinearTypesNotAllowed ->
text "Linear types are not supported in FFI declarations, see #18472"
OneArgExpected ->
text "One argument expected"
AtLeastOneArgExpected ->
text "At least one argument expected"
TcRnInvalidCIdentifier target
-> mkSimpleDecorated $
sep [quotes (ppr target) <+> text "is not a valid C identifier"]
TcRnExpectedValueId thing
-> mkSimpleDecorated $
ppr thing <+> text "used where a value identifier was expected"
TcRnRecSelectorEscapedTyVar lbl
-> mkSimpleDecorated $
text "Cannot use record selector" <+> quotes (ppr lbl) <+>
text "as a function due to escaped type variables"
TcRnPatSynNotBidirectional name
-> mkSimpleDecorated $
text "non-bidirectional pattern synonym"
<+> quotes (ppr name) <+> text "used in an expression"
TcRnIllegalDerivingItem hs_ty
-> mkSimpleDecorated $
text "Illegal deriving item" <+> quotes (ppr hs_ty)
TcRnIllegalDefaultClass hs_ty
-> mkSimpleDecorated $
quotes (ppr hs_ty) <+> text "is not a class"
TcRnIllegalNamedDefault hs_decl
-> mkSimpleDecorated $ text "Illegal use of default class name:" <+> quotes (ppr hs_decl)
TcRnUnexpectedAnnotation ty bang
-> mkSimpleDecorated $
let err = case bang of
HsBang SrcUnpack _ -> "UNPACK"
HsBang SrcNoUnpack _ -> "NOUNPACK"
HsBang NoSrcUnpack SrcLazy -> "laziness"
HsBang _ _ -> "strictness"
in text "Unexpected" <+> text err <+> text "annotation:" <+> ppr ty $$
text err <+> text "annotation cannot appear nested inside a type"
TcRnIllegalRecordSyntax either_ty_ty
-> mkSimpleDecorated $
text "Record syntax is illegal here:" <+> either ppr ppr either_ty_ty
TcRnInvalidVisibleKindArgument arg ty
-> mkSimpleDecorated $
text "Cannot apply function of kind" <+> quotes (ppr ty)
$$ text "to visible kind argument" <+> quotes (ppr arg)
TcRnTooManyBinders ki bndrs
-> mkSimpleDecorated $
hang (text "Not a function kind:")
4 (ppr ki) $$
hang (text "but extra binders found:")
4 (fsep (map ppr bndrs))
TcRnDifferentNamesForTyVar n1 n2
-> mkSimpleDecorated $
hang (text "Different names for the same type variable:") 2 info
where
info | nameOccName n1 /= nameOccName n2
= quotes (ppr n1) <+> text "and" <+> quotes (ppr n2)
| otherwise -- Same OccNames! See C2 in
-- Note [Swizzling the tyvars before generaliseTcTyCon]
= vcat [ quotes (ppr n1) <+> text "bound at" <+> ppr (getSrcLoc n1)
, quotes (ppr n2) <+> text "bound at" <+> ppr (getSrcLoc n2) ]
TcRnDisconnectedTyVar n
-> mkSimpleDecorated $
hang (text "Scoped type variable only appears non-injectively in declaration header:")
2 (quotes (ppr n) <+> text "bound at" <+> ppr (getSrcLoc n))
TcRnInvalidReturnKind data_sort allowed_kind kind _suggested_ext
-> mkSimpleDecorated $
sep [ ppDataSort data_sort <+>
text "has non-" <>
allowed_kind_tycon
, (if is_data_family then text "and non-variable" else empty) <+>
text "return kind" <+> quotes (ppr kind)
]
where
is_data_family =
case data_sort of
DataDeclSort{} -> False
DataInstanceSort{} -> False
DataFamilySort -> True
allowed_kind_tycon =
case allowed_kind of
AnyTYPEKind -> ppr tYPETyCon
AnyBoxedKind -> ppr boxedRepDataConTyCon
LiftedKind -> ppr liftedTypeKind
TcRnClassKindNotConstraint _kind
-> mkSimpleDecorated $
text "Kind signature on a class must end with" <+> ppr constraintKind $$
text "unobscured by type families"
TcRnUnpromotableThing name err
-> mkSimpleDecorated $
(hang (pprPECategory err <+> quotes (ppr name) <+> text "cannot be used here")
2 (parens reason))
where
reason = case err of
ConstrainedDataConPE theta
-> text "it has an unpromotable context"
<+> quotes (pprTheta theta)
FamDataConPE -> text "it comes from a data family instance"
PatSynPE -> text "pattern synonyms cannot be promoted"
RecDataConPE -> same_rec_group_msg
ClassPE -> same_rec_group_msg
TyConPE -> same_rec_group_msg
TermVariablePE -> text "term variables cannot be promoted"
TypeVariablePE -> text "type variables bound in a kind signature cannot be used in the type"
same_rec_group_msg = text "it is defined and used in the same recursive group"
TcRnIllegalTermLevelUse name err
-> mkSimpleDecorated $
text "Illegal term-level use of the" <+>
text (teCategory err) <+> quotes (ppr name)
TcRnMatchesHaveDiffNumArgs argsContext (MatchArgMatches match1 bad_matches)
-> mkSimpleDecorated $
(vcat [ pprMatchContextNouns argsContext <+>
text "have different numbers of arguments"
, nest 2 (ppr (getLocA match1))
, nest 2 (ppr (getLocA (NE.head bad_matches)))])
TcRnCannotBindScopedTyVarInPatSig sig_tvs
-> mkSimpleDecorated $
hang (text "You cannot bind scoped type variable"
<> plural (NE.toList sig_tvs)
<+> pprQuotedList (map fst $ NE.toList sig_tvs))
2 (text "in a pattern binding signature")
TcRnCannotBindTyVarsInPatBind _offenders
-> mkSimpleDecorated $
text "Binding type variables is not allowed in pattern bindings"
TcRnTooManyTyArgsInConPattern con_like expected_number actual_number
-> mkSimpleDecorated $
text "Too many type arguments in constructor pattern for" <+> quotes (ppr con_like) $$
text "Expected no more than" <+> ppr expected_number <> semi <+> text "got" <+> ppr actual_number
TcRnMultipleInlinePragmas poly_id fst_inl_prag inl_prags
-> mkSimpleDecorated $
hang (text "Multiple INLINE pragmas for" <+> ppr poly_id)
2 (vcat (text "Ignoring all but the first"
: map pp_inl (fst_inl_prag : NE.toList inl_prags)))
where
pp_inl (L loc prag) = ppr prag <+> parens (ppr loc)
TcRnUnexpectedPragmas poly_id bad_sigs
-> mkSimpleDecorated $
hang (text "Discarding unexpected pragmas for" <+> ppr poly_id)
2 (vcat (map (ppr . getLoc) $ NE.toList bad_sigs))
TcRnNonOverloadedSpecialisePragma fun_name
-> mkSimpleDecorated $
text "SPECIALISE pragma for non-overloaded function"
<+> quotes (ppr fun_name)
TcRnSpecialiseNotVisible name
-> mkSimpleDecorated $
text "You cannot SPECIALISE" <+> quotes (ppr name)
<+> text "because its definition is not visible in this module"
TcRnPragmaWarning
{ pragma_warning_info = PragmaWarningInstance{pwarn_dfunid, pwarn_ctorig}
, pragma_warning_msg }
-> mkSimpleDecorated $
sep [ hang (text "In the use of")
2 (pprDFunId pwarn_dfunid)
, ppr pwarn_ctorig
, pprWarningTxtForMsg pragma_warning_msg
]
TcRnPragmaWarning
{ pragma_warning_info = PragmaWarningDefault{pwarn_class, pwarn_impmod}
, pragma_warning_msg }
-> mkSimpleDecorated $
sep [ sep [ text "In the use of class"
<+> ppr pwarn_class
<+> text "defaults imported from"
<+> ppr pwarn_impmod <> colon ]
, pprWarningTxtForMsg pragma_warning_msg
]
TcRnPragmaWarning {pragma_warning_info, pragma_warning_msg}
-> mkSimpleDecorated $
sep [ sep [ text "In the use of"
<+> pprNonVarNameSpace (occNameSpace occ_name)
<+> quotes (ppr occ_name)
, parens imp_msg <> colon ]
, pprWarningTxtForMsg pragma_warning_msg ]
where
occ_name = pwarn_occname pragma_warning_info
imp_mod = pwarn_impmod pragma_warning_info
imp_msg = text "imported from" <+> ppr imp_mod <> extra
extra | PragmaWarningName {pwarn_declmod = decl_mod} <- pragma_warning_info
, imp_mod /= decl_mod = text ", but defined in" <+> ppr decl_mod
| otherwise = empty
TcRnDifferentExportWarnings name locs
-> mkSimpleDecorated $ vcat [quotes (ppr name) <+> text "exported with different error messages",
text "at" <+> vcat (map ppr $ sortBy leftmost_smallest $ NE.toList locs)]
TcRnIncompleteExportWarnings name locs
-> mkSimpleDecorated $ vcat [quotes (ppr name) <+> text "will not have its export warned about",
text "missing export warning at" <+> vcat (map ppr $ sortBy leftmost_smallest $ NE.toList locs)]
TcRnIllegalHsigDefaultMethods name meths
-> mkSimpleDecorated $
text "Illegal default method" <> plural (NE.toList meths) <+> text "in class definition of" <+> ppr name <+> text "in hsig file"
TcRnHsigFixityMismatch real_thing real_fixity sig_fixity
->
let ppr_fix f = ppr f <+> if f == defaultFixity then parens (text "default") else empty
in mkSimpleDecorated $
vcat [ppr real_thing <+> text "has conflicting fixities in the module",
text "and its hsig file",
text "Main module:" <+> ppr_fix real_fixity,
text "Hsig file:" <+> ppr_fix sig_fixity]
TcRnHsigShapeMismatch (HsigShapeSortMismatch info1 info2)
-> mkSimpleDecorated $
text "While merging export lists, could not combine"
<+> ppr info1 <+> text "with" <+> ppr info2
<+> parens (text "one is a type, the other is a plain identifier")
TcRnHsigShapeMismatch (HsigShapeNotUnifiable name1 name2 notHere)
->
let extra = if notHere
then text "Neither name variable originates from the current signature."
else empty
in mkSimpleDecorated $
text "While merging export lists, could not unify"
<+> ppr name1 <+> text "with" <+> ppr name2 $$ extra
TcRnHsigMissingModuleExport occ unit_state impl_mod
-> mkSimpleDecorated $
quotes (ppr occ)
<+> text "is exported by the hsig file, but not exported by the implementing module"
<+> quotes (pprWithUnitState unit_state $ ppr impl_mod)
TcRnBadGenericMethod clas op
-> mkSimpleDecorated $
hsep [text "Class", quotes (ppr clas),
text "has a generic-default signature without a binding", quotes (ppr op)]
TcRnWarningMinimalDefIncomplete mindef
-> mkSimpleDecorated $
vcat [ text "The MINIMAL pragma does not require:"
, nest 2 (pprBooleanFormulaNice mindef)
, text "but there is no default implementation." ]
TcRnDefaultMethodForPragmaLacksBinding sel_id prag
-> mkSimpleDecorated $
text "The" <+> hsSigDoc prag <+> text "for default method"
<+> quotes (ppr sel_id)
<+> text "lacks an accompanying binding"
TcRnIgnoreSpecialisePragmaOnDefMethod sel_name
-> mkSimpleDecorated $
text "Ignoring SPECIALISE pragmas on default method"
<+> quotes (ppr sel_name)
TcRnBadMethodErr{badMethodErrClassName, badMethodErrMethodName}
-> mkSimpleDecorated $
hsep [text "Class", quotes (ppr badMethodErrClassName),
text "does not have a method", quotes (ppr badMethodErrMethodName)]
TcRnIllegalTypeData
-> mkSimpleDecorated $
text "Illegal type-level data declaration"
TcRnTypeDataForbids feature
-> mkSimpleDecorated $
ppr feature <+> text "are not allowed in type data declarations."
TcRnIllegalNewtype con show_linear_types reason
-> mkSimpleDecorated $
vcat [msg, additional]
where
(msg,additional) =
case reason of
DoesNotHaveSingleField n_flds ->
(sep [
text "A newtype constructor must have exactly one field",
nest 2 $
text "but" <+> quotes (ppr con) <+> text "has" <+> speakN n_flds
],
ppr con <+> dcolon <+> ppr (dataConDisplayType show_linear_types con))
IsNonLinear ->
(text "A newtype constructor must be linear",
ppr con <+> dcolon <+> ppr (dataConDisplayType True con))
IsGADT ->
(text "A newtype must not be a GADT",
ppr con <+> dcolon <+> pprWithInvisibleBitsWhen sneaky_eq_spec
(ppr $ dataConDisplayType show_linear_types con))
HasConstructorContext ->
(text "A newtype constructor must not have a context in its type",
ppr con <+> dcolon <+> ppr (dataConDisplayType show_linear_types con))
HasExistentialTyVar ->
(text "A newtype constructor must not have existential type variables",
ppr con <+> dcolon <+> ppr (dataConDisplayType show_linear_types con))
HasStrictnessAnnotation ->
(text "A newtype constructor must not have a strictness annotation", empty)
-- Is the data con a "covert" GADT? See Note [isCovertGadtDataCon]
-- in GHC.Core.DataCon
sneaky_eq_spec = isCovertGadtDataCon con
TcRnOrPatBindsVariables bndrs -> mkSimpleDecorated $
text "An or-pattern may not bind term or type variables such as"
<+> quotedListWithOr (map ppr (NE.toList bndrs))
TcRnUnsatisfiedMinimalDef mindef
-> mkSimpleDecorated $
vcat [text "No explicit implementation for"
,nest 2 $ pprBooleanFormulaNice mindef
]
TcRnMisplacedInstSig name hs_ty
-> mkSimpleDecorated $
vcat [ hang (text "Illegal type signature in instance declaration:")
2 (hang (pprPrefixName name)
2 (dcolon <+> ppr hs_ty))
]
TcRnNoRebindableSyntaxRecordDot -> mkSimpleDecorated $
text "RebindableSyntax is required if OverloadedRecordUpdate is enabled."
TcRnNoFieldPunsRecordDot -> mkSimpleDecorated $
text "For this to work enable NamedFieldPuns"
TcRnIllegalStaticExpression e -> mkSimpleDecorated $
text "Illegal static expression:" <+> ppr e
TcRnListComprehensionDuplicateBinding n -> mkSimpleDecorated $
(text "Duplicate binding in parallel list comprehension for:"
<+> quotes (ppr n))
TcRnEmptyStmtsGroup cause -> mkSimpleDecorated $ case cause of
EmptyStmtsGroupInParallelComp ->
text "Empty statement group in parallel comprehension"
EmptyStmtsGroupInTransformListComp ->
text "Empty statement group preceding 'group' or 'then'"
EmptyStmtsGroupInDoNotation ctxt ->
text "Empty" <+> pprHsDoFlavour ctxt
EmptyStmtsGroupInArrowNotation ->
text "Empty 'do' block in an arrow command"
TcRnLastStmtNotExpr ctxt (UnexpectedStatement stmt) ->
mkSimpleDecorated $ hang last_error 2 (ppr stmt)
where
last_error =
text "The last statement in" <+> pprAStmtContext ctxt
<+> text "must be an expression"
TcRnUnexpectedStatementInContext ctxt (UnexpectedStatement stmt) _ -> mkSimpleDecorated $
sep [ text "Unexpected" <+> pprStmtCat stmt <+> text "statement"
, text "in" <+> pprAStmtContext ctxt ]
TcRnIllegalTupleSection -> mkSimpleDecorated $
text "Illegal tuple section"
TcRnIllegalImplicitParameterBindings eBinds -> mkSimpleDecorated $
either msg msg eBinds
where
msg binds = hang
(text "Implicit-parameter bindings illegal in an mdo expression")
2 (ppr binds)
TcRnSectionWithoutParentheses expr -> mkSimpleDecorated $
hang (text "A section must be enclosed in parentheses")
2 (text "thus:" <+> (parens (ppr expr)))
TcRnMissingRoleAnnotation name roles -> mkSimpleDecorated $
hang (text "Missing role annotation" <> colon)
2 (text "type role" <+> ppr name <+> hsep (map ppr roles))
TcRnIllformedTypePattern p
-> mkSimpleDecorated $
hang (text "Ill-formed type pattern:") 2 (ppr p)
TcRnIllegalTypePattern
-> mkSimpleDecorated $
text "Illegal type pattern." $$
text "A type pattern must be checked against a visible forall."
TcRnIllformedTypeArgument e
-> mkSimpleDecorated $
hang (text "Ill-formed type argument:") 2 (ppr e)
TcRnIllegalTypeExpr syntax -> mkSimpleDecorated $
vcat [ text "Illegal" <+> pprTypeSyntaxName syntax
, text "Type syntax may only be used in a required type argument,"
, text "i.e. to instantiate a visible forall." ]
TcRnCapturedTermName tv_name shadowed_term_names
-> mkSimpleDecorated $
text "The type variable" <+> quotes (ppr tv_name) <+>
text "is implicitly quantified," $+$
text "even though another variable of the same name is in scope:" $+$
nest 2 var_names $+$
text "This is not compatible with the RequiredTypeArguments extension."
where
var_names = case shadowed_term_names of
Left gbl_names -> vcat (map (\name -> quotes (ppr $ greName name) <+> pprNameProvenance name) gbl_names)
Right lcl_name -> quotes (ppr lcl_name) <+> text "defined at"
<+> ppr (nameSrcLoc lcl_name)
TcRnBindingOfExistingName name -> mkSimpleDecorated $
text "Illegal binding of an existing name:" <+> ppr (filterCTuple name)
TcRnMultipleFixityDecls loc rdr_name -> mkSimpleDecorated $
vcat [text "Multiple fixity declarations for" <+> quotes (ppr rdr_name),
text "also at " <+> ppr loc]
TcRnIllegalPatternSynonymDecl -> mkSimpleDecorated $
text "Illegal pattern synonym declaration"
TcRnIllegalClassBinding dsort bind -> mkSimpleDecorated $
vcat [ what <+> text "not allowed in" <+> decl_sort
, nest 2 (ppr bind) ]
where
decl_sort = case dsort of
ClassDeclSort -> text "class declaration:"
InstanceDeclSort -> text "instance declaration:"
what = case bind of
PatBind {} -> text "Pattern bindings (except simple variables)"
PatSynBind {} -> text "Pattern synonyms"
-- Associated pattern synonyms are not implemented yet
_ -> pprPanic "rnMethodBind" (ppr bind)
TcRnOrphanCompletePragma -> mkSimpleDecorated $
text "Orphan COMPLETE pragmas not supported" $$
text "A COMPLETE pragma must mention at least one data constructor" $$
text "or pattern synonym defined in the same module."
TcRnEmptyCase ctxt reason -> mkSimpleDecorated $
case reason of
EmptyCaseWithoutFlag ->
text "Empty list of alternatives in" <+> pp_ctxt
EmptyCaseDisallowedCtxt ->
text "Empty list of alternatives is not allowed in" <+> pp_ctxt
EmptyCaseForall tvb ->
vcat [ text "Empty list of alternatives in" <+> pp_ctxt
, hang (text "checked against a forall-type:")
2 (pprForAll [tvb] <+> text "...")
]
where
pp_ctxt = case ctxt of
CaseAlt -> text "case expression"
LamAlt LamCase -> text "\\case expression"
LamAlt LamCases -> text "\\cases expression"
ArrowMatchCtxt (ArrowLamAlt LamSingle) -> text "kappa abstraction"
ArrowMatchCtxt (ArrowLamAlt LamCase) -> text "\\case command"
ArrowMatchCtxt (ArrowLamAlt LamCases) -> text "\\cases command"
ArrowMatchCtxt ArrowCaseAlt -> text "case command"
ctxt -> text "(unexpected)" <+> pprMatchContextNoun ctxt
TcRnNonStdGuards (NonStandardGuards guards) -> mkSimpleDecorated $
text "accepting non-standard pattern guards" $$
nest 4 (interpp'SP guards)
TcRnDuplicateSigDecl pairs@((L _ name, sig) :| _) -> mkSimpleDecorated $
vcat [ text "Duplicate" <+> what_it_is
<> text "s for" <+> quotes (ppr name)
, text "at" <+> vcat (map ppr $ sortBy leftmost_smallest
$ map (getLocA . fst)
$ NE.toList pairs)
]
where
what_it_is = hsSigDoc sig
TcRnMisplacedSigDecl sig -> mkSimpleDecorated $
sep [text "Misplaced" <+> hsSigDoc sig <> colon, ppr sig]
TcRnUnexpectedDefaultSig sig -> mkSimpleDecorated $
hang (text "Unexpected default signature:")
2 (ppr sig)
TcRnDuplicateMinimalSig sig1 sig2 otherSigs -> mkSimpleDecorated $
vcat [ text "Multiple minimal complete definitions"
, text "at" <+> vcat (map ppr $ sortBy leftmost_smallest $ map getLocA sigs)
, text "Combine alternative minimal complete definitions with `|'" ]
where
sigs = sig1 : sig2 : otherSigs
TcRnUnexpectedStandaloneDerivingDecl -> mkSimpleDecorated $
text "Illegal standalone deriving declaration"
TcRnUnusedVariableInRuleDecl name var -> mkSimpleDecorated $
sep [text "Rule" <+> doubleQuotes (ftext name) <> colon,
text "Forall'd variable" <+> quotes (ppr var) <+>
text "does not appear on left hand side"]
TcRnUnexpectedStandaloneKindSig -> mkSimpleDecorated $
text "Illegal standalone kind signature"
TcRnIllegalRuleLhs errReason name lhs bad_e -> mkSimpleDecorated $
sep [text "Rule" <+> pprRuleName name <> colon,
nest 2 (vcat [err,
text "in left-hand side:" <+> ppr lhs])]
$$
text "LHS must be of form (f e1 .. en) where f is not forall'd"
where
err = case errReason of
UnboundVariable uv nis -> pprScopeError uv nis
IllegalExpression -> text "Illegal expression:" <+> ppr bad_e
TcRnDuplicateRoleAnnot list -> mkSimpleDecorated $
hang (text "Duplicate role annotations for" <+>
quotes (ppr $ roleAnnotDeclName first_decl) <> colon)
2 (vcat $ map pp_role_annot $ NE.toList sorted_list)
where
sorted_list = NE.sortBy cmp_loc list
((L _ first_decl) :| _) = sorted_list
pp_role_annot (L loc decl) = hang (ppr decl)
4 (text "-- written at" <+> ppr (locA loc))
cmp_loc = leftmost_smallest `on` getLocA
TcRnDuplicateKindSig list -> mkSimpleDecorated $
hang (text "Duplicate standalone kind signatures for" <+>
quotes (ppr $ standaloneKindSigName first_decl) <> colon)
2 (vcat $ map pp_kisig $ NE.toList sorted_list)
where
sorted_list = NE.sortBy cmp_loc list
((L _ first_decl) :| _) = sorted_list
pp_kisig (L loc decl) =
hang (ppr decl) 4 (text "-- written at" <+> ppr (locA loc))
cmp_loc = leftmost_smallest `on` getLocA
TcRnIllegalDerivStrategy ds -> mkSimpleDecorated $
text "Illegal deriving strategy" <> colon <+> derivStrategyName ds
TcRnIllegalMultipleDerivClauses -> mkSimpleDecorated $
text "Illegal use of multiple, consecutive deriving clauses"
TcRnNoDerivStratSpecified{} -> mkSimpleDecorated $ text
"No deriving strategy specified. Did you want stock, newtype, or anyclass?"
TcRnStupidThetaInGadt{} -> mkSimpleDecorated $
vcat [text "No context is allowed on a GADT-style data declaration",
text "(You can put a context on each constructor, though.)"]
TcRnShadowedTyVarNameInFamResult resName -> mkSimpleDecorated $
hsep [ text "Type variable", quotes (ppr resName) <> comma
, text "naming a type family result,"
] $$
text "shadows an already bound type variable"
TcRnIncorrectTyVarOnLhsOfInjCond resName injFrom -> mkSimpleDecorated $
vcat [ text $ "Incorrect type variable on the LHS of "
++ "injectivity condition"
, nest 5
( vcat [ text "Expected :" <+> ppr resName
, text "Actual :" <+> ppr injFrom ])]
TcRnUnknownTyVarsOnRhsOfInjCond errorVars -> mkSimpleDecorated $
hsep [ text "Unknown type variable" <> plural errorVars
, text "on the RHS of injectivity condition:"
, interpp'SP errorVars ]
TcRnBadlyStaged reason bind_lvl use_lvl
-> mkSimpleDecorated $
vcat $
[ text "Stage error:" <+> pprStageCheckReason reason <+>
hsep [text "is bound at stage" <+> ppr bind_lvl,
text "but used at stage" <+> ppr use_lvl]
] ++
[ hsep [ text "Hint: quoting" <+> thBrackets (ppUnless (isValName n) "t") (ppr n)
, text "or an enclosing expression would allow the quotation to be used in an earlier stage"
]
| StageCheckSplice n <- [reason]
]
TcRnBadlyStagedType name bind_lvl use_lvl
-> mkSimpleDecorated $
text "Badly staged type:" <+> ppr name <+>
hsep [text "is bound at stage" <+> ppr bind_lvl,
text "but used at stage" <+> ppr use_lvl]
TcRnStageRestriction reason
-> mkSimpleDecorated $
sep [ text "GHC stage restriction:"
, nest 2 (vcat [ pprStageCheckReason reason <+>
text "is used in a top-level splice, quasi-quote, or annotation,"
, text "and must be imported, not defined locally"])]
TcRnTyThingUsedWrong sort thing name
-> mkSimpleDecorated $
pprTyThingUsedWrong sort thing name
TcRnCannotDefaultKindVar var knd ->
mkSimpleDecorated $
(vcat [ text "Cannot default kind variable" <+> quotes (ppr var)
, text "of kind:" <+> ppr knd
, text "Perhaps enable PolyKinds or add a kind signature" ])
TcRnUninferrableTyVar tidied_tvs context ->
mkSimpleDecorated $
pprWithInvisibleBitsWhen True $
vcat [ text "Uninferrable type variable"
<> plural tidied_tvs
<+> pprWithCommas pprTyVar tidied_tvs
<+> text "in"
, pprUninferrableTyVarCtx context ]
TcRnSkolemEscape escapees tv orig_ty ->
mkSimpleDecorated $
pprWithInvisibleBitsWhen True $
vcat [ sep [ text "Cannot generalise type; skolem" <> plural escapees
, quotes $ pprTyVars escapees
, text "would escape" <+> itsOrTheir escapees <+> text "scope"
]
, sep [ text "if I tried to quantify"
, pprTyVar tv
, text "in this type:"
]
, nest 2 (pprTidiedType orig_ty)
, text "(Indeed, I sometimes struggle even printing this correctly,"
, text " due to its ill-scoped nature.)"
]
TcRnPatSynEscapedCoercion arg bad_co_ne -> mkSimpleDecorated $
vcat [ text "Iceland Jack! Iceland Jack! Stop torturing me!"
, hang (text "Pattern-bound variable")
2 (ppr arg <+> dcolon <+> ppr (idType arg))
, nest 2 $
hang (text "has a type that mentions pattern-bound coercion"
<> plural bad_co_list <> colon)
2 (pprWithCommas ppr bad_co_list)
, text "Hint: use -fprint-explicit-coercions to see the coercions"
, text "Probable fix: add a pattern signature" ]
where
bad_co_list = NE.toList bad_co_ne
TcRnPatSynExistentialInResult name pat_ty bad_tvs -> mkSimpleDecorated $
hang (sep [ text "The result type of the signature for" <+> quotes (ppr name) <> comma
, text "namely" <+> quotes (ppr pat_ty) ])
2 (text "mentions existential type variable" <> plural bad_tvs
<+> pprQuotedList bad_tvs)
TcRnPatSynArityMismatch name decl_arity missing -> mkSimpleDecorated $
hang (text "Pattern synonym" <+> quotes (ppr name) <+> text "has"
<+> speakNOf decl_arity (text "argument"))
2 (text "but its type signature has" <+> int missing <+> text "fewer arrows")
TcRnPatSynInvalidRhs ps_name lpat _ reason -> mkSimpleDecorated $
vcat [ hang (text "Invalid right-hand side of bidirectional pattern synonym"
<+> quotes (ppr ps_name) <> colon)
2 (pprPatSynInvalidRhsReason reason)
, text "RHS pattern:" <+> ppr lpat ]
TcRnTyFamDepsDisabled -> mkSimpleDecorated $
text "Illegal injectivity annotation"
TcRnAbstractClosedTyFamDecl -> mkSimpleDecorated $
text "You may define an abstract closed type family" $$
text "only in a .hs-boot file"
TcRnPartialFieldSelector fld -> mkSimpleDecorated $
vcat [ sep [ text "Definition of partial record field" <> colon
, nest 2 $ quotes (ppr (occName fld)) ]
, text "Record selection and update using this field will be partial." ]
TcRnHasFieldResolvedIncomplete name -> mkSimpleDecorated $
text "The invocation of `getField` on the record field" <+> quotes (ppr name)
<+> text "may produce an error since it is not defined for all data constructors"
TcRnBadFieldAnnotation n con reason -> mkSimpleDecorated $
hang (pprBadFieldAnnotationReason reason)
2 (text "on the" <+> speakNth n
<+> text "argument of" <+> quotes (ppr con))
TcRnSuperclassCycle (MkSuperclassCycle cls definite details) ->
let herald | definite = text "Superclass cycle for"
| otherwise = text "Potential superclass cycle for"
in mkSimpleDecorated $
vcat [ herald <+> quotes (ppr cls), nest 2 (vcat (pprSuperclassCycleDetail <$> details))]
TcRnDefaultSigMismatch sel_id dm_ty -> mkSimpleDecorated $
hang (text "The default type signature for"
<+> ppr sel_id <> colon)
2 (ppr dm_ty)
$$ (text "does not match its corresponding"
<+> text "non-default type signature")
TcRnTyFamsDisabled reason -> mkSimpleDecorated $
text "Illegal family" <+> text sort <+> text "for" <+> quotes name
where
(sort, name) = case reason of
TyFamsDisabledFamily n -> ("declaration", ppr n)
TyFamsDisabledInstance n -> ("instance", ppr n)
TcRnBadTyConTelescope tc -> mkSimpleDecorated $
vcat [ hang (text "The kind of" <+> quotes (ppr tc) <+> text "is ill-scoped")
2 pp_tc_kind
, extra
, hang (text "Perhaps try this order instead:")
2 (pprTyVars sorted_tvs) ]
where
pp_tc_kind = text "Inferred kind:" <+> ppr tc <+> dcolon <+> ppr_untidy (tyConKind tc)
ppr_untidy ty = pprIfaceType (toIfaceType ty)
-- We need ppr_untidy here because pprType will tidy the type, which
-- will turn the bogus kind we are trying to report
-- T :: forall (a::k) k (b::k) -> blah
-- into a misleadingly sanitised version
-- T :: forall (a::k) k1 (b::k1) -> blah
tcbs = tyConBinders tc
tvs = binderVars tcbs
sorted_tvs = scopedSort tvs
inferred_tvs = [ binderVar tcb
| tcb <- tcbs, Inferred == tyConBinderForAllTyFlag tcb ]
specified_tvs = [ binderVar tcb
| tcb <- tcbs, Specified == tyConBinderForAllTyFlag tcb ]
extra
| null inferred_tvs && null specified_tvs
= empty
| null inferred_tvs
= note $ "Specified variables" <+> pp_spec <+> "always come first"
| null specified_tvs
= note inf_always_first
| otherwise
= note $ inf_always_first $$
"then specified variables" <+> pp_spec
inf_always_first = "Inferred variables" <+> pp_inf $$ "always come first"
pp_inf = parens (text "namely:" <+> pprTyVars inferred_tvs)
pp_spec = parens (text "namely:" <+> pprTyVars specified_tvs)
TcRnTyFamResultDisabled tc_name tvb -> mkSimpleDecorated $
text "Illegal result type variable" <+> ppr tvb <+> text "for" <+> quotes (ppr tc_name)
TcRnRoleValidationFailed role reason -> mkSimpleDecorated $
vcat [text "Internal error in role inference:",
pprRoleValidationFailedReason role reason,
text "Please report this as a GHC bug: https://www.haskell.org/ghc/reportabug"]
TcRnCommonFieldResultTypeMismatch con1 con2 field_name -> mkSimpleDecorated $
vcat [sep [text "Constructors" <+> ppr con1 <+> text "and" <+> ppr con2,
text "have a common field" <+> quotes (ppr field_name) <> comma],
nest 2 $ text "but have different result types"]
TcRnCommonFieldTypeMismatch con1 con2 field_name -> mkSimpleDecorated $
sep [text "Constructors" <+> ppr con1 <+> text "and" <+> ppr con2,
text "give different types for field", quotes (ppr field_name)]
TcRnClassExtensionDisabled cls reason -> mkSimpleDecorated $
pprDisabledClassExtension cls reason
TcRnDataConParentTypeMismatch data_con res_ty_tmpl -> mkSimpleDecorated $
hang (text "Data constructor" <+> quotes (ppr data_con) <+>
text "returns type" <+> quotes (ppr actual_res_ty))
2 (text "instead of an instance of its parent type" <+> quotes (ppr res_ty_tmpl))
where
actual_res_ty = dataConOrigResTy data_con
TcRnGADTsDisabled tc_name -> mkSimpleDecorated $
text "Illegal generalised algebraic data declaration for" <+> quotes (ppr tc_name)
TcRnExistentialQuantificationDisabled con -> mkSimpleDecorated $
sdocOption sdocLinearTypes (\show_linear_types ->
hang (text "Data constructor" <+> quotes (ppr con) <+>
text "has existential type variables, a context, or a specialised result type")
2 (ppr con <+> dcolon <+> ppr (dataConDisplayType show_linear_types con)))
TcRnGADTDataContext tc_name -> mkSimpleDecorated $
text "A data type declared in GADT style cannot have a context:" <+> quotes (ppr tc_name)
TcRnMultipleConForNewtype tycon n -> mkSimpleDecorated $
sep [text "A newtype must have exactly one constructor,",
nest 2 $ text "but" <+> quotes (ppr tycon) <+> text "has" <+> speakN n]
TcRnKindSignaturesDisabled thing -> mkSimpleDecorated $
text "Illegal kind signature" <+> quotes (either ppr with_sig thing)
where
with_sig (tc_name, ksig) = ppr tc_name <+> dcolon <+> ppr ksig
TcRnEmptyDataDeclsDisabled tycon -> mkSimpleDecorated $
quotes (ppr tycon) <+> text "has no constructors"
TcRnRoleMismatch var annot inferred -> mkSimpleDecorated $
hang (text "Role mismatch on variable" <+> ppr var <> colon)
2 (sep [ text "Annotation says", ppr annot
, text "but role", ppr inferred
, text "is required" ])
TcRnRoleCountMismatch tyvars d@(L _ (RoleAnnotDecl _ _ annots)) -> mkSimpleDecorated $
hang (text "Wrong number of roles listed in role annotation;" $$
text "Expected" <+> (ppr tyvars) <> comma <+>
text "got" <+> (ppr $ length annots) <> colon)
2 (ppr d)
TcRnIllegalRoleAnnotation (RoleAnnotDecl _ tycon _) -> mkSimpleDecorated $
(text "Illegal role annotation for" <+> ppr tycon <> char ';' $$
text "they are allowed only for datatypes and classes.")
TcRnRoleAnnotationsDisabled tc -> mkSimpleDecorated $
text "Illegal role annotation for" <+> ppr tc
TcRnIncoherentRoles _ -> mkSimpleDecorated $
(text "Roles other than" <+> quotes (text "nominal") <+>
text "for class parameters can lead to incoherence.")
TcRnUnexpectedKindVar tv_name
-> mkSimpleDecorated $ text "Unexpected kind variable" <+> quotes (ppr tv_name)
TcRnNegativeNumTypeLiteral tyLit
-> mkSimpleDecorated $ text "Illegal literal in type (type literals must not be negative):" <+> ppr tyLit
TcRnIllegalKind ty_thing _
-> mkSimpleDecorated $ text "Illegal kind:" <+> (ppr ty_thing)
TcRnPrecedenceParsingError op1 op2
-> mkSimpleDecorated $
hang (text "Precedence parsing error")
4 (hsep [text "cannot mix", ppr_opfix op1, text "and",
ppr_opfix op2,
text "in the same infix expression"])
TcRnSectionPrecedenceError op arg_op section
-> mkSimpleDecorated $
vcat [text "The operator" <+> ppr_opfix op <+> text "of a section",
nest 4 (sep [text "must have lower precedence than that of the operand,",
nest 2 (text "namely" <+> ppr_opfix arg_op)]),
nest 4 (text "in the section:" <+> quotes (ppr section))]
TcRnUnexpectedPatSigType ty
-> mkSimpleDecorated $
hang (text "Illegal type signature:" <+> quotes (ppr ty))
2 (text "Type signatures are only allowed in patterns with ScopedTypeVariables")
TcRnIllegalKindSignature ty
-> mkSimpleDecorated $ text "Illegal kind signature:" <+> quotes (ppr ty)
TcRnUnusedQuantifiedTypeVar doc tyVar
-> mkSimpleDecorated $
vcat [ text "Unused quantified type variable" <+> quotes (ppr tyVar)
, inHsDocContext doc ]
TcRnDataKindsError typeOrKind thing
-- See Note [Checking for DataKinds] (Wrinkle: Migration story for
-- DataKinds typechecker errors) in GHC.Tc.Validity for why we give
-- different diagnostic messages below.
-> case thing of
Left renamer_thing ->
mkSimpleDecorated $
text "Illegal" <+> ppr_level <> colon <+> quotes (ppr renamer_thing)
Right typechecker_thing ->
mkSimpleDecorated $ vcat
[ text "An occurrence of" <+> quotes (ppr typechecker_thing) <+>
text "in a" <+> ppr_level <+> text "requires DataKinds."
, text "Future versions of GHC will turn this warning into an error."
]
where
ppr_level = text $ levelString typeOrKind
TcRnTypeSynonymCycle decl_or_tcs
-> mkSimpleDecorated $
sep [ text "Cycle in type synonym declarations:"
, nest 2 (vcat (map ppr_decl decl_or_tcs)) ]
where
ppr_decl = \case
Right (L loc decl) -> ppr (locA loc) <> colon <+> ppr decl
Left tc ->
let n = tyConName tc
in ppr (getSrcSpan n) <> colon <+> ppr (tyConName tc)
<+> text "from external module"
TcRnZonkerMessage err
-> mkSimpleDecorated $ pprZonkerMessage err
TcRnInterfaceError reason
-> diagnosticMessage (tcOptsIfaceOpts opts) reason
TcRnSelfImport imp_mod_name
-> mkSimpleDecorated $
text "A module cannot import itself:" <+> ppr imp_mod_name
TcRnNoExplicitImportList mod
-> mkSimpleDecorated $
text "The module" <+> quotes (ppr mod) <+> text "does not have an explicit import list"
TcRnSafeImportsDisabled _
-> mkSimpleDecorated $
text "safe import can't be used as Safe Haskell isn't on!"
TcRnDeprecatedModule mod txt
-> mkSimpleDecorated $
sep [ text "Module" <+> quotes (ppr mod) <> text extra <> colon,
nest 2 (vcat (map (ppr . hsDocString . unLoc) msg)) ]
where
(extra, msg) = case txt of
WarningTxt _ _ msg -> ("", msg)
DeprecatedTxt _ msg -> (" is deprecated", msg)
TcRnRedundantSourceImport mod_name
-> mkSimpleDecorated $
text "Unnecessary {-# SOURCE #-} in the import of module" <+> quotes (ppr mod_name)
TcRnImportLookup reason
-> mkSimpleDecorated $
pprImportLookup reason
TcRnUnusedImport decl reason
-> mkSimpleDecorated $
pprUnusedImport decl reason
TcRnDuplicateDecls name sorted_names
-> mkSimpleDecorated $
vcat [text "Multiple declarations of" <+>
quotes (ppr name),
-- NB. print the OccName, not the Name, because the
-- latter might not be in scope in the RdrEnv and so will
-- be printed qualified.
text "Declared at:" <+>
vcat (NE.toList $ ppr . nameSrcLoc <$> sorted_names)]
TcRnPackageImportsDisabled
-> mkSimpleDecorated $
text "Package-qualified imports are not enabled"
TcRnIllegalDataCon name
-> mkSimpleDecorated $
hsep [text "Illegal data constructor name", quotes (ppr name)]
TcRnNestedForallsContexts entity
-> mkSimpleDecorated $
what <+> text "cannot contain nested"
<+> quotes forAllLit <> text "s or contexts"
where
what = case entity of
NFC_Specialize -> text "SPECIALISE instance type"
NFC_ViaType -> quotes (text "via") <+> text "type"
NFC_GadtConSig -> text "GADT constructor type signature"
NFC_InstanceHead -> text "Instance head"
NFC_StandaloneDerivedInstanceHead -> text "Standalone-derived instance head"
NFC_DerivedClassType -> text "Derived class type"
TcRnRedundantRecordWildcard
-> mkSimpleDecorated $
text "Record wildcard does not bind any new variables"
TcRnUnusedRecordWildcard _
-> mkSimpleDecorated $
text "No variables bound in the record wildcard match are used"
TcRnUnusedName name reason
-> mkSimpleDecorated $
pprUnusedName name reason
TcRnQualifiedBinder rdr_name
-> mkSimpleDecorated $
text "Qualified name in binding position:" <+> ppr rdr_name
TcRnTypeApplicationsDisabled ty_app
-> mkSimpleDecorated $
text "Illegal visible" <+> what <+> text "application" <+> ctx <> colon
<+> ppr arg
where
arg = case ty_app of
TypeApplication ty _ -> char '@' <> ppr ty
TypeApplicationInPattern ty_app -> ppr ty_app
what = case ty_app of
TypeApplication _ ty_or_ki ->
case ty_or_ki of
TypeLevel -> text "type"
KindLevel -> text "kind"
TypeApplicationInPattern _ -> text "type"
ctx = case ty_app of
TypeApplicationInPattern _ -> text "in a pattern"
_ -> empty
TcRnInvalidRecordField con field
-> mkSimpleDecorated $
hsep [text "Constructor" <+> quotes (ppr con),
text "does not have field", quotes (ppr field)]
TcRnTupleTooLarge tup_size
-> mkSimpleDecorated $
sep [text "A" <+> int tup_size <> text "-tuple is too large for GHC",
nest 2 (parens (text "max size is" <+> int mAX_TUPLE_SIZE)),
nest 2 (text "Workaround: use nested tuples or define a data type")]
TcRnCTupleTooLarge tup_size
-> mkSimpleDecorated $
hang (text "Constraint tuple arity too large:" <+> int tup_size
<+> parens (text "max arity =" <+> int mAX_CTUPLE_SIZE))
2 (text "Instead, use a nested tuple")
TcRnIllegalInferredTyVars _
-> mkSimpleDecorated $
text "Inferred type variables are not allowed"
TcRnAmbiguousName gre_env name gres
-> mkSimpleDecorated $
vcat [ text "Ambiguous occurrence" <+> quotes (ppr name) <> dot
, text "It could refer to"
, nest 3 (vcat msgs) ]
where
np1 NE.:| nps = gres
msgs = punctuateFinal comma dot $
text "either" <+> ppr_gre np1
: [text " or" <+> ppr_gre np | np <- nps]
ppr_gre gre = pprAmbiguousGreName gre_env gre
TcRnBindingNameConflict name locs
-> mkSimpleDecorated $
vcat [text "Conflicting definitions for" <+> quotes (ppr name),
locations]
where
locations =
text "Bound at:"
<+> vcat (map ppr (sortBy leftmost_smallest (NE.toList locs)))
TcRnNonCanonicalDefinition reason inst_ty
-> mkSimpleDecorated $
pprNonCanonicalDefinition inst_ty reason
TcRnDefaultedExceptionContext ct_loc ->
mkSimpleDecorated $ vcat [ header, warning, proposal ]
where
header, warning, proposal :: SDoc
header
= vcat [ text "Solving for an implicit ExceptionContext constraint"
, nest 2 $ pprCtOrigin (ctLocOrigin ct_loc) <> text "." ]
warning
= vcat [ text "Future versions of GHC will turn this warning into an error." ]
proposal
= vcat [ text "See GHC Proposal #330." ]
TcRnImplicitImportOfPrelude
-> mkSimpleDecorated $
text "Module" <+> quotes (text "Prelude") <+> text "implicitly imported."
TcRnMissingMain explicit_export_list main_mod main_occ
-> mkSimpleDecorated $
text "The" <+> ppMainFn main_occ
<+> text "is not" <+> defOrExp <+> text "module"
<+> quotes (ppr main_mod)
where
defOrExp :: SDoc
defOrExp | explicit_export_list = text "exported by"
| otherwise = text "defined in"
TcRnGhciUnliftedBind id
-> mkSimpleDecorated $
sep [ text "GHCi can't bind a variable of unlifted type:"
, nest 2 (pprPrefixOcc id <+> dcolon <+> ppr (idType id)) ]
TcRnGhciMonadLookupFail ty lookups
-> mkSimpleDecorated $
hang (text "Can't find type" <+> pp_ty <> dot $$ ambig_msg)
2 (text "When checking that" <+> pp_ty <>
text "is a monad that can execute GHCi statements.")
where
pp_ty = quotes (text ty)
ambig_msg = case lookups of
Just (_:_:_) -> text "The type is ambiguous."
_ -> empty
TcRnIllegalQuasiQuotes -> mkSimpleDecorated $
text "Quasi-quotes are not permitted without QuasiQuotes"
TcRnTHError err -> pprTHError err
TcRnPatersonCondFailure reason ctxt lhs rhs ->
mkSimpleDecorated $ pprPatersonCondFailure reason ctxt lhs rhs
TcRnIllegalInvisTyVarBndr bndr ->
mkSimpleDecorated $
hang (text "Illegal invisible type variable binder:")
2 (ppr bndr)
TcRnIllegalWildcardTyVarBndr bndr ->
mkSimpleDecorated $
hang (text "Illegal wildcard binder:")
2 (ppr bndr)
TcRnInvalidInvisTyVarBndr name hs_bndr ->
mkSimpleDecorated $
vcat [ hang (text "Invalid invisible type variable binder:")
2 (ppr hs_bndr)
, text "There is no matching forall-bound variable"
, text "in the standalone kind signature for" <+> quotes (ppr name) <> dot
, note $ vcat [
"Only" <+> quotes "forall a." <+> "-quantification matches invisible binders,",
"whereas" <+> quotes "forall {a}." <+> "and" <+> quotes "forall a ->" <+> "do not"
]]
TcRnDeprecatedInvisTyArgInConPat ->
mkSimpleDecorated $
cat [ text "Type applications in constructor patterns will require"
, text "the TypeAbstractions extension starting from GHC 9.14." ]
TcRnInvisBndrWithoutSig _ hs_bndr ->
mkSimpleDecorated $
vcat [ hang (text "Invalid invisible type variable binder:")
2 (ppr hs_bndr)
, text "Either a standalone kind signature (SAKS)"
, text "or a complete user-supplied kind (CUSK, legacy feature)"
, text "is required to use invisible binders." ]
TcRnImplicitRhsQuantification kv -> mkSimpleDecorated $
vcat [ text "The variable" <+> quotes (ppr kv) <+> text "occurs free on the RHS of the type declaration"
, text "In the future GHC will no longer implicitly quantify over such variables"
]
TcRnInvalidDefaultedTyVar wanteds proposal bad_tvs ->
mkSimpleDecorated $
pprWithInvisibleBitsWhen True $
vcat [ text "Invalid defaulting proposal."
, hang (text "The following type variable" <> plural (NE.toList bad_tvs) <+> text "cannot be defaulted, as" <+> why <> colon)
2 (pprQuotedList (NE.toList bad_tvs))
, hang (text "Defaulting proposal:")
2 (ppr proposal)
, hang (text "Wanted constraints:")
2 (pprQuotedList (map ctPred wanteds))
]
where
why
| _ :| [] <- bad_tvs
= text "it is not an unfilled metavariable"
| otherwise
= text "they are not unfilled metavariables"
TcRnNamespacedWarningPragmaWithoutFlag warning@(Warning (kw, _) _ txt) -> mkSimpleDecorated $
vcat [ text "Illegal use of the" <+> quotes (ppr kw) <+> text "keyword:"
, nest 2 (ppr warning)
, text "in a" <+> pragma_type <+> text "pragma"
]
where
pragma_type = case txt of
WarningTxt{} -> text "WARNING"
DeprecatedTxt{} -> text "DEPRECATED"
TcRnIllegalInvisibleTypePattern tp -> mkSimpleDecorated $
text "Illegal invisible type pattern:" <+> ppr tp
TcRnInvisPatWithNoForAll tp -> mkSimpleDecorated $
text "Invisible type pattern" <+> ppr tp <+> text "has no associated forall"
TcRnNamespacedFixitySigWithoutFlag sig@(FixitySig kw _ _) -> mkSimpleDecorated $
vcat [ text "Illegal use of the" <+> quotes (ppr kw) <+> text "keyword:"
, nest 2 (ppr sig)
, text "in a fixity signature"
]
TcRnOutOfArityTyVar ts_name tv_name -> mkDecorated
[ vcat [ text "The arity of" <+> quotes (ppr ts_name) <+> text "is insufficiently high to accommodate"
, text "an implicit binding for the" <+> quotes (ppr tv_name) <+> text "type variable." ]
, suggestion ]
where
suggestion =
text "Use" <+> quotes at_bndr <+> text "on the LHS" <+>
text "or" <+> quotes forall_bndr <+> text "on the RHS" <+>
text "to bring it into scope."
at_bndr = char '@' <> ppr tv_name
forall_bndr = text "forall" <+> ppr tv_name <> text "."
TcRnMisplacedInvisPat tp -> mkSimpleDecorated $
text "Invisible type pattern" <+> ppr tp <+> text "is not allowed here"
TcRnUnexpectedTypeSyntaxInTerms syntax -> mkSimpleDecorated $
text "Unexpected" <+> pprTypeSyntaxName syntax
diagnosticReason :: TcRnMessage -> DiagnosticReason
diagnosticReason = \case
TcRnUnknownMessage m
-> diagnosticReason m
TcRnMessageWithInfo _ msg_with_info
-> case msg_with_info of
TcRnMessageDetailed _ m -> diagnosticReason m
TcRnWithHsDocContext _ msg
-> diagnosticReason msg
TcRnSolverReport _ reason
-> reason -- Error, or a Warning if we are deferring type errors
TcRnSolverDepthError {}
-> ErrorWithoutFlag
TcRnRedundantConstraints {}
-> WarningWithFlag Opt_WarnRedundantConstraints
TcRnInaccessibleCode {}
-> WarningWithFlag Opt_WarnInaccessibleCode
TcRnInaccessibleCoAxBranch {}
-> WarningWithFlag Opt_WarnInaccessibleCode
TcRnTypeDoesNotHaveFixedRuntimeRep{}
-> ErrorWithoutFlag
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
TcRnInvalidWarningCategory{}
-> ErrorWithoutFlag
TcRnDuplicateWarningDecls{}
-> ErrorWithoutFlag
TcRnSimplifierTooManyIterations{}
-> ErrorWithoutFlag
TcRnIllegalPatSynDecl{}
-> ErrorWithoutFlag
TcRnLinearPatSyn{}
-> ErrorWithoutFlag
TcRnEmptyRecordUpdate
-> ErrorWithoutFlag
TcRnIllegalFieldPunning{}
-> ErrorWithoutFlag
TcRnIllegalWildcardsInRecord{}
-> ErrorWithoutFlag
TcRnIllegalWildcardInType{}
-> ErrorWithoutFlag
TcRnIllegalNamedWildcardInTypeArgument{}
-> ErrorWithoutFlag
TcRnIllegalImplicitTyVarInTypeArgument{}
-> ErrorWithoutFlag
TcRnDuplicateFieldName{}
-> ErrorWithoutFlag
TcRnIllegalViewPattern{}
-> ErrorWithoutFlag
TcRnCharLiteralOutOfRange{}
-> ErrorWithoutFlag
TcRnIllegalWildcardsInConstructor{}
-> ErrorWithoutFlag
TcRnIgnoringAnnotations{}
-> WarningWithoutFlag
TcRnAnnotationInSafeHaskell
-> ErrorWithoutFlag
TcRnInvalidTypeApplication{}
-> ErrorWithoutFlag
TcRnTagToEnumMissingValArg
-> ErrorWithoutFlag
TcRnTagToEnumUnspecifiedResTy{}
-> ErrorWithoutFlag
TcRnTagToEnumResTyNotAnEnum{}
-> ErrorWithoutFlag
TcRnTagToEnumResTyTypeData{}
-> ErrorWithoutFlag
TcRnArrowIfThenElsePredDependsOnResultTy
-> ErrorWithoutFlag
TcRnIllegalHsBootOrSigDecl {}
-> ErrorWithoutFlag
TcRnBootMismatch {}
-> ErrorWithoutFlag
TcRnRecursivePatternSynonym{}
-> ErrorWithoutFlag
TcRnPartialTypeSigTyVarMismatch{}
-> ErrorWithoutFlag
TcRnPartialTypeSigBadQuantifier{}
-> ErrorWithoutFlag
TcRnMissingSignature what exported
-> WarningWithFlags $ missingSignatureWarningFlags what exported
TcRnPolymorphicBinderMissingSig{}
-> WarningWithFlag Opt_WarnMissingLocalSignatures
TcRnOverloadedSig{}
-> ErrorWithoutFlag
TcRnTupleConstraintInst{}
-> ErrorWithoutFlag
TcRnUserTypeError{}
-> ErrorWithoutFlag
TcRnConstraintInKind{}
-> ErrorWithoutFlag
TcRnUnboxedTupleOrSumTypeFuncArg{}
-> ErrorWithoutFlag
TcRnLinearFuncInKind{}
-> ErrorWithoutFlag
TcRnForAllEscapeError{}
-> ErrorWithoutFlag
TcRnSimplifiableConstraint{}
-> WarningWithFlag Opt_WarnSimplifiableClassConstraints
TcRnArityMismatch{}
-> ErrorWithoutFlag
TcRnIllegalInstance rea
-> illegalInstanceReason rea
TcRnVDQInTermType{}
-> ErrorWithoutFlag
TcRnBadQuantPredHead{}
-> ErrorWithoutFlag
TcRnIllegalTupleConstraint{}
-> ErrorWithoutFlag
TcRnNonTypeVarArgInConstraint{}
-> ErrorWithoutFlag
TcRnIllegalImplicitParam{}
-> ErrorWithoutFlag
TcRnIllegalConstraintSynonymOfKind{}
-> ErrorWithoutFlag
TcRnOversaturatedVisibleKindArg{}
-> ErrorWithoutFlag
TcRnForAllRankErr{}
-> ErrorWithoutFlag
TcRnMonomorphicBindings{}
-> WarningWithFlag Opt_WarnMonomorphism
TcRnOrphanInstance{}
-> WarningWithFlag Opt_WarnOrphans
TcRnFunDepConflict{}
-> ErrorWithoutFlag
TcRnDupInstanceDecls{}
-> ErrorWithoutFlag
TcRnConflictingFamInstDecls{}
-> ErrorWithoutFlag
TcRnFamInstNotInjective{}
-> ErrorWithoutFlag
TcRnBangOnUnliftedType{}
-> WarningWithFlag Opt_WarnRedundantStrictnessFlags
TcRnLazyBangOnUnliftedType{}
-> 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
TcRnExportHiddenDefault{}
-> ErrorWithoutFlag
TcRnDuplicateExport{}
-> WarningWithFlag Opt_WarnDuplicateExports
TcRnExportedParentChildMismatch{}
-> ErrorWithoutFlag
TcRnConflictingExports{}
-> ErrorWithoutFlag
TcRnDuplicateFieldExport {}
-> ErrorWithoutFlag
TcRnAmbiguousFieldInUpdate {}
-> ErrorWithoutFlag
TcRnAmbiguousRecordUpdate{}
-> WarningWithFlag Opt_WarnAmbiguousFields
TcRnMissingFields{}
-> WarningWithFlag Opt_WarnMissingFields
TcRnFieldUpdateInvalidType{}
-> ErrorWithoutFlag
TcRnMissingStrictFields{}
-> ErrorWithoutFlag
TcRnBadRecordUpdate{}
-> ErrorWithoutFlag
TcRnIllegalStaticExpression {}
-> 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
TcRnLookupInstance _ _ _
-> ErrorWithoutFlag
TcRnLazyGADTPattern
-> ErrorWithoutFlag
TcRnArrowProcGADTPattern
-> ErrorWithoutFlag
TcRnTypeEqualityOutOfScope
-> WarningWithFlag Opt_WarnTypeEqualityOutOfScope
TcRnTypeEqualityRequiresOperators
-> WarningWithFlag Opt_WarnTypeEqualityRequiresOperators
TcRnIllegalTypeOperator {}
-> ErrorWithoutFlag
TcRnIllegalTypeOperatorDecl {}
-> ErrorWithoutFlag
TcRnGADTMonoLocalBinds {}
-> WarningWithFlag Opt_WarnGADTMonoLocalBinds
TcRnIncorrectNameSpace {}
-> ErrorWithoutFlag
TcRnNotInScope {}
-> ErrorWithoutFlag
TcRnTermNameInType {}
-> ErrorWithoutFlag
TcRnUntickedPromotedThing {}
-> WarningWithFlag Opt_WarnUntickedPromotedConstructors
TcRnIllegalBuiltinSyntax {}
-> ErrorWithoutFlag
TcRnWarnDefaulting {}
-> WarningWithFlag Opt_WarnTypeDefaults
TcRnWarnClashingDefaultImports {}
-> WarningWithFlag Opt_WarnTypeDefaults
TcRnForeignImportPrimExtNotSet{}
-> ErrorWithoutFlag
TcRnForeignImportPrimSafeAnn{}
-> ErrorWithoutFlag
TcRnForeignFunctionImportAsValue{}
-> ErrorWithoutFlag
TcRnFunPtrImportWithoutAmpersand{}
-> WarningWithFlag Opt_WarnDodgyForeignImports
TcRnIllegalForeignDeclBackend{}
-> ErrorWithoutFlag
TcRnUnsupportedCallConv _ unsupportedCC
-> case unsupportedCC of
StdCallConvUnsupported -> WarningWithFlag Opt_WarnUnsupportedCallingConventions
_ -> ErrorWithoutFlag
TcRnIllegalForeignType{}
-> ErrorWithoutFlag
TcRnInvalidCIdentifier{}
-> ErrorWithoutFlag
TcRnExpectedValueId{}
-> ErrorWithoutFlag
TcRnRecSelectorEscapedTyVar{}
-> ErrorWithoutFlag
TcRnPatSynNotBidirectional{}
-> ErrorWithoutFlag
TcRnIllegalDerivingItem{}
-> ErrorWithoutFlag
TcRnIllegalDefaultClass{}
-> ErrorWithoutFlag
TcRnIllegalNamedDefault{}
-> ErrorWithoutFlag
TcRnUnexpectedAnnotation{}
-> ErrorWithoutFlag
TcRnIllegalRecordSyntax{}
-> ErrorWithoutFlag
TcRnInvalidVisibleKindArgument{}
-> ErrorWithoutFlag
TcRnTooManyBinders{}
-> ErrorWithoutFlag
TcRnDifferentNamesForTyVar{}
-> ErrorWithoutFlag
TcRnDisconnectedTyVar{}
-> ErrorWithoutFlag
TcRnInvalidReturnKind{}
-> ErrorWithoutFlag
TcRnClassKindNotConstraint{}
-> ErrorWithoutFlag
TcRnUnpromotableThing{}
-> ErrorWithoutFlag
TcRnIllegalTermLevelUse{}
-> ErrorWithoutFlag
TcRnMatchesHaveDiffNumArgs{}
-> ErrorWithoutFlag
TcRnCannotBindScopedTyVarInPatSig{}
-> ErrorWithoutFlag
TcRnCannotBindTyVarsInPatBind{}
-> ErrorWithoutFlag
TcRnTooManyTyArgsInConPattern{}
-> ErrorWithoutFlag
TcRnMultipleInlinePragmas{}
-> WarningWithoutFlag
TcRnUnexpectedPragmas{}
-> WarningWithoutFlag
TcRnNonOverloadedSpecialisePragma{}
-> WarningWithoutFlag
TcRnSpecialiseNotVisible{}
-> WarningWithoutFlag
TcRnPragmaWarning{pragma_warning_msg}
-> WarningWithCategory (warningTxtCategory pragma_warning_msg)
TcRnDifferentExportWarnings _ _
-> ErrorWithoutFlag
TcRnIncompleteExportWarnings _ _
-> WarningWithFlag Opt_WarnIncompleteExportWarnings
TcRnIllegalHsigDefaultMethods{}
-> ErrorWithoutFlag
TcRnHsigFixityMismatch{}
-> ErrorWithoutFlag
TcRnHsigShapeMismatch{}
-> ErrorWithoutFlag
TcRnHsigMissingModuleExport{}
-> ErrorWithoutFlag
TcRnBadGenericMethod{}
-> ErrorWithoutFlag
TcRnWarningMinimalDefIncomplete{}
-> WarningWithoutFlag
TcRnDefaultMethodForPragmaLacksBinding{}
-> ErrorWithoutFlag
TcRnIgnoreSpecialisePragmaOnDefMethod{}
-> WarningWithoutFlag
TcRnBadMethodErr{}
-> ErrorWithoutFlag
TcRnIllegalTypeData
-> ErrorWithoutFlag
TcRnIllegalQuasiQuotes{}
-> ErrorWithoutFlag
TcRnTHError err
-> thErrorReason err
TcRnTypeDataForbids{}
-> ErrorWithoutFlag
TcRnIllegalNewtype{}
-> ErrorWithoutFlag
TcRnOrPatBindsVariables{}
-> ErrorWithoutFlag
TcRnUnsatisfiedMinimalDef{}
-> WarningWithFlag (Opt_WarnMissingMethods)
TcRnMisplacedInstSig{}
-> ErrorWithoutFlag
TcRnNoRebindableSyntaxRecordDot{}
-> ErrorWithoutFlag
TcRnNoFieldPunsRecordDot{}
-> ErrorWithoutFlag
TcRnListComprehensionDuplicateBinding{}
-> ErrorWithoutFlag
TcRnEmptyStmtsGroup{}
-> ErrorWithoutFlag
TcRnLastStmtNotExpr{}
-> ErrorWithoutFlag
TcRnUnexpectedStatementInContext{}
-> ErrorWithoutFlag
TcRnSectionWithoutParentheses{}
-> ErrorWithoutFlag
TcRnIllegalImplicitParameterBindings{}
-> ErrorWithoutFlag
TcRnIllegalTupleSection{}
-> ErrorWithoutFlag
TcRnCapturedTermName{}
-> WarningWithFlag Opt_WarnTermVariableCapture
TcRnBindingOfExistingName{}
-> ErrorWithoutFlag
TcRnMultipleFixityDecls{}
-> ErrorWithoutFlag
TcRnIllegalPatternSynonymDecl{}
-> ErrorWithoutFlag
TcRnIllegalClassBinding{}
-> ErrorWithoutFlag
TcRnOrphanCompletePragma{}
-> ErrorWithoutFlag
TcRnEmptyCase{}
-> ErrorWithoutFlag
TcRnNonStdGuards{}
-> WarningWithoutFlag
TcRnDuplicateSigDecl{}
-> ErrorWithoutFlag
TcRnMisplacedSigDecl{}
-> ErrorWithoutFlag
TcRnUnexpectedDefaultSig{}
-> ErrorWithoutFlag
TcRnDuplicateMinimalSig{}
-> ErrorWithoutFlag
TcRnUnexpectedStandaloneDerivingDecl{}
-> ErrorWithoutFlag
TcRnUnusedVariableInRuleDecl{}
-> ErrorWithoutFlag
TcRnUnexpectedStandaloneKindSig{}
-> ErrorWithoutFlag
TcRnIllegalRuleLhs{}
-> ErrorWithoutFlag
TcRnDuplicateRoleAnnot{}
-> ErrorWithoutFlag
TcRnDuplicateKindSig{}
-> ErrorWithoutFlag
TcRnIllegalDerivStrategy{}
-> ErrorWithoutFlag
TcRnIllegalMultipleDerivClauses{}
-> ErrorWithoutFlag
TcRnNoDerivStratSpecified{}
-> WarningWithFlag Opt_WarnMissingDerivingStrategies
TcRnStupidThetaInGadt{}
-> ErrorWithoutFlag
TcRnShadowedTyVarNameInFamResult{}
-> ErrorWithoutFlag
TcRnIncorrectTyVarOnLhsOfInjCond{}
-> ErrorWithoutFlag
TcRnUnknownTyVarsOnRhsOfInjCond{}
-> ErrorWithoutFlag
TcRnBadlyStaged{}
-> ErrorWithoutFlag
TcRnBadlyStagedType{}
-> WarningWithFlag Opt_WarnBadlyStagedTypes
TcRnStageRestriction{}
-> ErrorWithoutFlag
TcRnTyThingUsedWrong{}
-> ErrorWithoutFlag
TcRnCannotDefaultKindVar{}
-> ErrorWithoutFlag
TcRnUninferrableTyVar{}
-> ErrorWithoutFlag
TcRnSkolemEscape{}
-> ErrorWithoutFlag
TcRnPatSynEscapedCoercion{}
-> ErrorWithoutFlag
TcRnPatSynExistentialInResult{}
-> ErrorWithoutFlag
TcRnPatSynArityMismatch{}
-> ErrorWithoutFlag
TcRnPatSynInvalidRhs{}
-> ErrorWithoutFlag
TcRnTyFamDepsDisabled{}
-> ErrorWithoutFlag
TcRnAbstractClosedTyFamDecl{}
-> ErrorWithoutFlag
TcRnPartialFieldSelector{}
-> WarningWithFlag Opt_WarnPartialFields
TcRnHasFieldResolvedIncomplete{}
-> WarningWithFlag Opt_WarnIncompleteRecordSelectors
TcRnBadFieldAnnotation _ _ LazyFieldsDisabled
-> ErrorWithoutFlag
TcRnBadFieldAnnotation{}
-> WarningWithoutFlag
TcRnSuperclassCycle{}
-> ErrorWithoutFlag
TcRnDefaultSigMismatch{}
-> ErrorWithoutFlag
TcRnTyFamsDisabled{}
-> ErrorWithoutFlag
TcRnBadTyConTelescope {}
-> ErrorWithoutFlag
TcRnTyFamResultDisabled{}
-> ErrorWithoutFlag
TcRnRoleValidationFailed{}
-> ErrorWithoutFlag
TcRnCommonFieldResultTypeMismatch{}
-> ErrorWithoutFlag
TcRnCommonFieldTypeMismatch{}
-> ErrorWithoutFlag
TcRnClassExtensionDisabled{}
-> ErrorWithoutFlag
TcRnDataConParentTypeMismatch{}
-> ErrorWithoutFlag
TcRnGADTsDisabled{}
-> ErrorWithoutFlag
TcRnExistentialQuantificationDisabled{}
-> ErrorWithoutFlag
TcRnGADTDataContext{}
-> ErrorWithoutFlag
TcRnMultipleConForNewtype{}
-> ErrorWithoutFlag
TcRnKindSignaturesDisabled{}
-> ErrorWithoutFlag
TcRnEmptyDataDeclsDisabled{}
-> ErrorWithoutFlag
TcRnRoleMismatch{}
-> ErrorWithoutFlag
TcRnRoleCountMismatch{}
-> ErrorWithoutFlag
TcRnIllegalRoleAnnotation{}
-> ErrorWithoutFlag
TcRnRoleAnnotationsDisabled{}
-> ErrorWithoutFlag
TcRnIncoherentRoles{}
-> ErrorWithoutFlag
TcRnUnexpectedKindVar{}
-> ErrorWithoutFlag
TcRnNegativeNumTypeLiteral{}
-> ErrorWithoutFlag
TcRnIllegalKind{}
-> ErrorWithoutFlag
TcRnPrecedenceParsingError{}
-> ErrorWithoutFlag
TcRnSectionPrecedenceError{}
-> ErrorWithoutFlag
TcRnUnexpectedPatSigType{}
-> ErrorWithoutFlag
TcRnIllegalKindSignature{}
-> ErrorWithoutFlag
TcRnUnusedQuantifiedTypeVar{}
-> WarningWithFlag Opt_WarnUnusedForalls
TcRnDataKindsError _ thing
-- DataKinds errors can arise from either the renamer (Left) or the
-- typechecker (Right). The latter category of DataKinds errors are a
-- fairly recent addition to GHC (introduced in GHC 9.10), and in order
-- to prevent these new errors from breaking users' code, we temporarily
-- downgrade these errors to warnings. See Note [Checking for DataKinds]
-- (Wrinkle: Migration story for DataKinds typechecker errors)
-- in GHC.Tc.Validity.
-> case thing of
Left _ -> ErrorWithoutFlag
Right _ -> WarningWithFlag Opt_WarnDataKindsTC
TcRnTypeSynonymCycle{}
-> ErrorWithoutFlag
TcRnZonkerMessage msg
-> zonkerMessageReason msg
TcRnInterfaceError err
-> interfaceErrorReason err
TcRnSelfImport{}
-> ErrorWithoutFlag
TcRnNoExplicitImportList{}
-> WarningWithFlag Opt_WarnMissingImportList
TcRnSafeImportsDisabled{}
-> ErrorWithoutFlag
TcRnDeprecatedModule _ txt
-> WarningWithCategory (warningTxtCategory txt)
TcRnRedundantSourceImport{}
-> WarningWithoutFlag
TcRnImportLookup{}
-> ErrorWithoutFlag
TcRnUnusedImport{}
-> WarningWithFlag Opt_WarnUnusedImports
TcRnDuplicateDecls{}
-> ErrorWithoutFlag
TcRnPackageImportsDisabled
-> ErrorWithoutFlag
TcRnIllegalDataCon{}
-> ErrorWithoutFlag
TcRnNestedForallsContexts{}
-> ErrorWithoutFlag
TcRnRedundantRecordWildcard
-> WarningWithFlag Opt_WarnRedundantRecordWildcards
TcRnUnusedRecordWildcard{}
-> WarningWithFlag Opt_WarnUnusedRecordWildcards
TcRnUnusedName _ prov
-> WarningWithFlag $ case prov of
UnusedNameTopDecl -> Opt_WarnUnusedTopBinds
UnusedNameImported _ -> Opt_WarnUnusedTopBinds
UnusedNameTypePattern -> Opt_WarnUnusedTypePatterns
UnusedNameMatch -> Opt_WarnUnusedMatches
UnusedNameLocalBind -> Opt_WarnUnusedLocalBinds
TcRnQualifiedBinder{}
-> ErrorWithoutFlag
TcRnTypeApplicationsDisabled{}
-> ErrorWithoutFlag
TcRnInvalidRecordField{}
-> ErrorWithoutFlag
TcRnTupleTooLarge{}
-> ErrorWithoutFlag
TcRnCTupleTooLarge{}
-> ErrorWithoutFlag
TcRnIllegalInferredTyVars{}
-> ErrorWithoutFlag
TcRnAmbiguousName{}
-> ErrorWithoutFlag
TcRnBindingNameConflict{}
-> ErrorWithoutFlag
TcRnNonCanonicalDefinition (NonCanonicalMonoid _) _
-> WarningWithFlag Opt_WarnNonCanonicalMonoidInstances
TcRnNonCanonicalDefinition (NonCanonicalMonad _) _
-> WarningWithFlag Opt_WarnNonCanonicalMonadInstances
TcRnDefaultedExceptionContext{}
-> WarningWithFlag Opt_WarnDefaultedExceptionContext
TcRnImplicitImportOfPrelude {}
-> WarningWithFlag Opt_WarnImplicitPrelude
TcRnMissingMain {}
-> ErrorWithoutFlag
TcRnGhciUnliftedBind {}
-> ErrorWithoutFlag
TcRnGhciMonadLookupFail {}
-> ErrorWithoutFlag
TcRnMissingRoleAnnotation{}
-> WarningWithFlag Opt_WarnMissingRoleAnnotations
TcRnIllegalInvisTyVarBndr{}
-> ErrorWithoutFlag
TcRnIllegalWildcardTyVarBndr{}
-> ErrorWithoutFlag
TcRnDeprecatedInvisTyArgInConPat {}
-> WarningWithFlag Opt_WarnDeprecatedTypeAbstractions
TcRnInvalidInvisTyVarBndr{}
-> ErrorWithoutFlag
TcRnInvisBndrWithoutSig{}
-> ErrorWithoutFlag
TcRnImplicitRhsQuantification{}
-> WarningWithFlag Opt_WarnImplicitRhsQuantification
TcRnPatersonCondFailure{}
-> ErrorWithoutFlag
TcRnIllformedTypePattern{}
-> ErrorWithoutFlag
TcRnIllegalTypePattern{}
-> ErrorWithoutFlag
TcRnIllformedTypeArgument{}
-> ErrorWithoutFlag
TcRnIllegalTypeExpr{}
-> ErrorWithoutFlag
TcRnInvalidDefaultedTyVar{}
-> ErrorWithoutFlag
TcRnNamespacedWarningPragmaWithoutFlag{}
-> ErrorWithoutFlag
TcRnIllegalInvisibleTypePattern{}
-> ErrorWithoutFlag
TcRnInvisPatWithNoForAll{}
-> ErrorWithoutFlag
TcRnNamespacedFixitySigWithoutFlag{}
-> ErrorWithoutFlag
TcRnOutOfArityTyVar{}
-> ErrorWithoutFlag
TcRnMisplacedInvisPat{}
-> ErrorWithoutFlag
TcRnUnexpectedTypeSyntaxInTerms{}
-> ErrorWithoutFlag
diagnosticHints = \case
TcRnUnknownMessage m
-> diagnosticHints m
TcRnMessageWithInfo _ msg_with_info
-> case msg_with_info of
TcRnMessageDetailed _ m -> diagnosticHints m
TcRnWithHsDocContext _ msg
-> diagnosticHints msg
TcRnSolverReport (SolverReportWithCtxt ctxt msg) _
-> tcSolverReportMsgHints ctxt msg
TcRnSolverDepthError {}
-> [SuggestIncreaseReductionDepth]
TcRnRedundantConstraints{}
-> noHints
TcRnInaccessibleCode{}
-> noHints
TcRnInaccessibleCoAxBranch{}
-> noHints
TcRnTypeDoesNotHaveFixedRuntimeRep{}
-> noHints
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
TcRnInvalidWarningCategory{}
-> noHints
TcRnDuplicateWarningDecls{}
-> noHints
TcRnSimplifierTooManyIterations{}
-> [SuggestIncreaseSimplifierIterations]
TcRnIllegalPatSynDecl{}
-> noHints
TcRnLinearPatSyn{}
-> noHints
TcRnEmptyRecordUpdate{}
-> noHints
TcRnIllegalFieldPunning{}
-> [suggestExtension LangExt.NamedFieldPuns]
TcRnIllegalWildcardsInRecord{}
-> [suggestExtension LangExt.RecordWildCards]
TcRnIllegalWildcardInType{}
-> noHints
TcRnIllegalNamedWildcardInTypeArgument{}
-> [SuggestAnonymousWildcard]
TcRnIllegalImplicitTyVarInTypeArgument tv
-> [SuggestExplicitQuantification tv]
TcRnDuplicateFieldName{}
-> noHints
TcRnIllegalViewPattern{}
-> [suggestExtension LangExt.ViewPatterns]
TcRnCharLiteralOutOfRange{}
-> noHints
TcRnIllegalWildcardsInConstructor{}
-> noHints
TcRnIgnoringAnnotations{}
-> noHints
TcRnAnnotationInSafeHaskell
-> noHints
TcRnInvalidTypeApplication{}
-> noHints
TcRnTagToEnumMissingValArg
-> noHints
TcRnTagToEnumUnspecifiedResTy{}
-> noHints
TcRnTagToEnumResTyNotAnEnum{}
-> noHints
TcRnTagToEnumResTyTypeData{}
-> noHints
TcRnArrowIfThenElsePredDependsOnResultTy
-> noHints
TcRnIllegalHsBootOrSigDecl {}
-> noHints
TcRnBootMismatch boot_or_sig err
| Hsig <- boot_or_sig
, BootMismatch _ _ (BootMismatchedTyCons _boot_tc real_tc tc_errs) <- err
, any is_synAbsData_etaReduce (NE.toList tc_errs)
-> [SuggestEtaReduceAbsDataTySyn real_tc]
| otherwise
-> noHints
where
is_synAbsData_etaReduce (SynAbstractData SynAbsDataTySynNotNullary) = True
is_synAbsData_etaReduce _ = False
TcRnRecursivePatternSynonym{}
-> noHints
TcRnPartialTypeSigTyVarMismatch{}
-> noHints
TcRnPartialTypeSigBadQuantifier{}
-> noHints
TcRnMissingSignature {}
-> noHints
TcRnPolymorphicBinderMissingSig{}
-> noHints
TcRnOverloadedSig{}
-> noHints
TcRnTupleConstraintInst{}
-> noHints
TcRnUserTypeError{}
-> noHints
TcRnConstraintInKind{}
-> noHints
TcRnUnboxedTupleOrSumTypeFuncArg tuple_or_sum _
-> [suggestExtension $ unboxedTupleOrSumExtension tuple_or_sum]
TcRnLinearFuncInKind{}
-> noHints
TcRnForAllEscapeError{}
-> noHints
TcRnVDQInTermType mb_ty
| isJust mb_ty -> [suggestExtension LangExt.RequiredTypeArguments]
| otherwise -> []
TcRnBadQuantPredHead{}
-> noHints
TcRnIllegalTupleConstraint{}
-> [suggestExtension LangExt.ConstraintKinds]
TcRnNonTypeVarArgInConstraint{}
-> [suggestExtension LangExt.FlexibleContexts]
TcRnIllegalImplicitParam{}
-> noHints
TcRnIllegalConstraintSynonymOfKind{}
-> [suggestExtension LangExt.ConstraintKinds]
TcRnOversaturatedVisibleKindArg{}
-> 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
TcRnSimplifiableConstraint{}
-> noHints
TcRnArityMismatch{}
-> noHints
TcRnIllegalInstance rea
-> illegalInstanceHints rea
TcRnMonomorphicBindings bindings
-> case bindings of
[] -> noHints
(x:xs) -> [SuggestAddTypeSignatures $ NamedBindings (x NE.:| xs)]
TcRnOrphanInstance clsOrFamInst
-> [SuggestFixOrphanInst { isFamilyInstance = isFam }]
where
isFam = case clsOrFamInst :: Either ClsInst FamInst of
Left _clsInst -> Nothing
Right famInst -> Just $ fi_flavor famInst
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
TcRnLazyBangOnUnliftedType{}
-> noHints
TcRnMultipleDefaultDeclarations{}
-> noHints
TcRnBadDefaultType{}
-> noHints
TcRnPatSynBundledWithNonDataCon{}
-> noHints
TcRnPatSynBundledWithWrongType{}
-> noHints
TcRnDupeModuleExport{}
-> noHints
TcRnExportedModNotImported{}
-> noHints
TcRnNullExportedModule{}
-> noHints
TcRnMissingExportList{}
-> noHints
TcRnExportHiddenComponents{}
-> noHints
TcRnExportHiddenDefault{}
-> noHints
TcRnDuplicateExport{}
-> noHints
TcRnExportedParentChildMismatch{}
-> noHints
TcRnConflictingExports{}
-> noHints
TcRnDuplicateFieldExport {}
-> [suggestExtension LangExt.DuplicateRecordFields]
TcRnAmbiguousFieldInUpdate {}
-> [suggestExtension LangExt.DisambiguateRecordFields]
TcRnAmbiguousRecordUpdate{}
-> noHints
TcRnMissingFields{}
-> noHints
TcRnFieldUpdateInvalidType{}
-> noHints
TcRnMissingStrictFields{}
-> noHints
TcRnBadRecordUpdate{}
-> noHints
TcRnIllegalStaticExpression {}
-> [suggestExtension LangExt.StaticPointers]
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
TcRnLookupInstance _ _ _
-> noHints
TcRnLazyGADTPattern
-> noHints
TcRnArrowProcGADTPattern
-> noHints
TcRnTypeEqualityOutOfScope
-> noHints
TcRnTypeEqualityRequiresOperators
-> [suggestExtension LangExt.TypeOperators]
TcRnIllegalTypeOperator {}
-> [suggestExtension LangExt.TypeOperators]
TcRnIllegalTypeOperatorDecl {}
-> [suggestExtension LangExt.TypeOperators]
TcRnGADTMonoLocalBinds {}
-> [suggestAnyExtension [LangExt.GADTs, LangExt.TypeFamilies]]
TcRnIncorrectNameSpace nm is_th_use
| is_th_use
-> [SuggestAppropriateTHTick $ nameNameSpace nm]
| otherwise
-> noHints
TcRnNotInScope err _ _ hints
-> scopeErrorHints err ++ hints
TcRnTermNameInType _ hints
-> hints
TcRnUntickedPromotedThing thing
-> [SuggestAddTick thing]
TcRnIllegalBuiltinSyntax {}
-> noHints
TcRnWarnDefaulting {}
-> noHints
TcRnWarnClashingDefaultImports cls local imports
-> suggestDefaultDeclaration cls (fold local) (cd_types <$> NE.toList imports)
TcRnForeignImportPrimExtNotSet{}
-> [suggestExtension LangExt.GHCForeignImportPrim]
TcRnForeignImportPrimSafeAnn{}
-> noHints
TcRnForeignFunctionImportAsValue{}
-> noHints
TcRnFunPtrImportWithoutAmpersand{}
-> noHints
TcRnIllegalForeignDeclBackend{}
-> noHints
TcRnUnsupportedCallConv{}
-> noHints
TcRnIllegalForeignType _ reason
-> case reason of
TypeCannotBeMarshaled _ why
| NewtypeDataConNotInScope tc _ <- why
-> let tc_nm = tyConName tc
dc = dataConName $ head $ tyConDataCons tc
in [ ImportSuggestion (occName dc)
$ ImportDataCon Nothing (nameOccName tc_nm) ]
| UnliftedFFITypesNeeded <- why
-> [suggestExtension LangExt.UnliftedFFITypes]
_ -> noHints
TcRnInvalidCIdentifier{}
-> noHints
TcRnExpectedValueId{}
-> noHints
TcRnRecSelectorEscapedTyVar{}
-> [SuggestPatternMatchingSyntax]
TcRnPatSynNotBidirectional{}
-> noHints
TcRnIllegalDerivingItem{}
-> noHints
TcRnIllegalDefaultClass{}
-> noHints
TcRnIllegalNamedDefault{}
-> [suggestExtension LangExt.NamedDefaults]
TcRnUnexpectedAnnotation{}
-> noHints
TcRnIllegalRecordSyntax{}
-> noHints
TcRnInvalidVisibleKindArgument{}
-> noHints
TcRnTooManyBinders{}
-> noHints
TcRnDifferentNamesForTyVar{}
-> noHints
TcRnDisconnectedTyVar n
-> [SuggestBindTyVarExplicitly n]
TcRnInvalidReturnKind _ _ _ mb_suggest_unlifted_ext
-> case mb_suggest_unlifted_ext of
Nothing -> noHints
Just SuggestUnliftedNewtypes -> [suggestExtension LangExt.UnliftedNewtypes]
Just SuggestUnliftedDatatypes -> [suggestExtension LangExt.UnliftedDatatypes]
TcRnClassKindNotConstraint{}
-> noHints
TcRnUnpromotableThing{}
-> noHints
TcRnIllegalTermLevelUse{}
-> noHints
TcRnMatchesHaveDiffNumArgs{}
-> noHints
TcRnCannotBindScopedTyVarInPatSig{}
-> noHints
TcRnCannotBindTyVarsInPatBind{}
-> noHints
TcRnTooManyTyArgsInConPattern{}
-> noHints
TcRnMultipleInlinePragmas{}
-> noHints
TcRnUnexpectedPragmas{}
-> noHints
TcRnNonOverloadedSpecialisePragma{}
-> noHints
TcRnSpecialiseNotVisible name
-> [SuggestSpecialiseVisibilityHints name]
TcRnPragmaWarning{}
-> noHints
TcRnDifferentExportWarnings _ _
-> noHints
TcRnIncompleteExportWarnings _ _
-> noHints
TcRnIllegalHsigDefaultMethods{}
-> noHints
TcRnIllegalQuasiQuotes{}
-> [suggestExtension LangExt.QuasiQuotes]
TcRnTHError err
-> thErrorHints err
TcRnHsigFixityMismatch{}
-> noHints
TcRnHsigShapeMismatch{}
-> noHints
TcRnHsigMissingModuleExport{}
-> noHints
TcRnBadGenericMethod{}
-> noHints
TcRnWarningMinimalDefIncomplete{}
-> noHints
TcRnDefaultMethodForPragmaLacksBinding{}
-> noHints
TcRnIgnoreSpecialisePragmaOnDefMethod{}
-> noHints
TcRnBadMethodErr{}
-> noHints
TcRnIllegalTypeData
-> [suggestExtension LangExt.TypeData]
TcRnTypeDataForbids{}
-> noHints
TcRnIllegalNewtype{}
-> noHints
TcRnOrPatBindsVariables{}
-> noHints
TcRnUnsatisfiedMinimalDef{}
-> noHints
TcRnMisplacedInstSig{}
-> [suggestExtension LangExt.InstanceSigs]
TcRnNoRebindableSyntaxRecordDot{}
-> noHints
TcRnNoFieldPunsRecordDot{}
-> noHints
TcRnListComprehensionDuplicateBinding{}
-> noHints
TcRnEmptyStmtsGroup EmptyStmtsGroupInDoNotation{}
-> [suggestExtension LangExt.NondecreasingIndentation]
TcRnEmptyStmtsGroup{}
-> noHints
TcRnLastStmtNotExpr{}
-> noHints
TcRnUnexpectedStatementInContext _ _ mExt
| Nothing <- mExt -> noHints
| Just ext <- mExt -> [suggestExtension ext]
TcRnSectionWithoutParentheses{}
-> noHints
TcRnIllegalImplicitParameterBindings{}
-> noHints
TcRnIllegalTupleSection{}
-> [suggestExtension LangExt.TupleSections]
TcRnCapturedTermName{}
-> [SuggestRenameTypeVariable]
TcRnBindingOfExistingName{}
-> noHints
TcRnMultipleFixityDecls{}
-> noHints
TcRnIllegalPatternSynonymDecl{}
-> [suggestExtension LangExt.PatternSynonyms]
TcRnIllegalClassBinding{}
-> noHints
TcRnOrphanCompletePragma{}
-> noHints
TcRnEmptyCase _ reason ->
case reason of
EmptyCaseWithoutFlag{} -> [suggestExtension LangExt.EmptyCase]
EmptyCaseDisallowedCtxt{} -> noHints
EmptyCaseForall{} -> noHints
TcRnNonStdGuards{}
-> [suggestExtension LangExt.PatternGuards]
TcRnDuplicateSigDecl{}
-> noHints
TcRnMisplacedSigDecl{}
-> noHints
TcRnUnexpectedDefaultSig{}
-> [suggestExtension LangExt.DefaultSignatures]
TcRnDuplicateMinimalSig{}
-> noHints
TcRnUnexpectedStandaloneDerivingDecl{}
-> [suggestExtension LangExt.StandaloneDeriving]
TcRnUnusedVariableInRuleDecl{}
-> noHints
TcRnUnexpectedStandaloneKindSig{}
-> [suggestExtension LangExt.StandaloneKindSignatures]
TcRnIllegalRuleLhs{}
-> noHints
TcRnDuplicateRoleAnnot{}
-> noHints
TcRnDuplicateKindSig{}
-> noHints
TcRnIllegalDerivStrategy ds -> case ds of
ViaStrategy{} -> [suggestExtension LangExt.DerivingVia]
_ -> [suggestExtension LangExt.DerivingStrategies]
TcRnIllegalMultipleDerivClauses{}
-> [suggestExtension LangExt.DerivingStrategies]
TcRnNoDerivStratSpecified is_ds_enabled info -> do
let explicit_strategy_hint = case info of
TcRnNoDerivingClauseStrategySpecified assumed_derivings ->
SuggestExplicitDerivingClauseStrategies assumed_derivings
TcRnNoStandaloneDerivingStrategySpecified assumed_strategy deriv_sig ->
SuggestExplicitStandaloneDerivingStrategy assumed_strategy deriv_sig
explicit_strategy_hint : [suggestExtension LangExt.DerivingStrategies | not is_ds_enabled]
TcRnStupidThetaInGadt{}
-> noHints
TcRnShadowedTyVarNameInFamResult{}
-> noHints
TcRnIncorrectTyVarOnLhsOfInjCond{}
-> noHints
TcRnUnknownTyVarsOnRhsOfInjCond{}
-> noHints
TcRnBadlyStaged{}
-> noHints
TcRnBadlyStagedType{}
-> noHints
TcRnStageRestriction{}
-> noHints
TcRnTyThingUsedWrong{}
-> noHints
TcRnCannotDefaultKindVar{}
-> noHints
TcRnUninferrableTyVar{}
-> noHints
TcRnSkolemEscape{}
-> noHints
TcRnPatSynEscapedCoercion{}
-> noHints
TcRnPatSynExistentialInResult{}
-> noHints
TcRnPatSynArityMismatch{}
-> noHints
TcRnPatSynInvalidRhs name pat args (PatSynNotInvertible _)
-> [SuggestExplicitBidiPatSyn name pat args]
TcRnPatSynInvalidRhs{}
-> noHints
TcRnTyFamDepsDisabled{}
-> [suggestExtension LangExt.TypeFamilyDependencies]
TcRnAbstractClosedTyFamDecl{}
-> noHints
TcRnPartialFieldSelector{}
-> noHints
TcRnHasFieldResolvedIncomplete{}
-> noHints
TcRnBadFieldAnnotation _ _ LazyFieldsDisabled
-> [suggestExtension LangExt.StrictData]
TcRnBadFieldAnnotation{}
-> noHints
TcRnSuperclassCycle{}
-> [suggestExtension LangExt.UndecidableSuperClasses]
TcRnDefaultSigMismatch{}
-> noHints
TcRnTyFamsDisabled{}
-> [suggestExtension LangExt.TypeFamilies]
TcRnBadTyConTelescope{}
-> noHints
TcRnTyFamResultDisabled{}
-> [suggestExtension LangExt.TypeFamilyDependencies]
TcRnRoleValidationFailed{}
-> noHints
TcRnCommonFieldResultTypeMismatch{}
-> noHints
TcRnCommonFieldTypeMismatch{}
-> noHints
TcRnClassExtensionDisabled _ MultiParamDisabled{}
-> [suggestExtension LangExt.MultiParamTypeClasses]
TcRnClassExtensionDisabled _ FunDepsDisabled{}
-> [suggestExtension LangExt.FunctionalDependencies]
TcRnClassExtensionDisabled _ ConstrainedClassMethodsDisabled{}
-> [suggestExtension LangExt.ConstrainedClassMethods]
TcRnDataConParentTypeMismatch{}
-> noHints
TcRnGADTsDisabled{}
-> [suggestExtension LangExt.GADTs]
TcRnExistentialQuantificationDisabled{}
-> [suggestAnyExtension [LangExt.ExistentialQuantification, LangExt.GADTs]]
TcRnGADTDataContext{}
-> noHints
TcRnMultipleConForNewtype{}
-> noHints
TcRnKindSignaturesDisabled{}
-> [suggestExtension LangExt.KindSignatures]
TcRnEmptyDataDeclsDisabled{}
-> [suggestExtension LangExt.EmptyDataDecls]
TcRnRoleMismatch{}
-> noHints
TcRnRoleCountMismatch{}
-> noHints
TcRnIllegalRoleAnnotation{}
-> noHints
TcRnRoleAnnotationsDisabled{}
-> [suggestExtension LangExt.RoleAnnotations]
TcRnIncoherentRoles{}
-> [suggestExtension LangExt.IncoherentInstances]
TcRnUnexpectedKindVar{}
-> [suggestExtension LangExt.PolyKinds]
TcRnNegativeNumTypeLiteral{}
-> noHints
TcRnIllegalKind _ suggest_polyKinds
-> if suggest_polyKinds
then [suggestExtension LangExt.PolyKinds]
else noHints
TcRnPrecedenceParsingError{}
-> noHints
TcRnSectionPrecedenceError{}
-> noHints
TcRnUnexpectedPatSigType{}
-> [suggestExtension LangExt.ScopedTypeVariables]
TcRnIllegalKindSignature{}
-> [suggestExtension LangExt.KindSignatures]
TcRnUnusedQuantifiedTypeVar{}
-> noHints
TcRnDataKindsError{}
-> [suggestExtension LangExt.DataKinds]
TcRnTypeSynonymCycle{}
-> noHints
TcRnZonkerMessage msg
-> zonkerMessageHints msg
TcRnInterfaceError reason
-> interfaceErrorHints reason
TcRnSelfImport{}
-> noHints
TcRnNoExplicitImportList{}
-> noHints
TcRnSafeImportsDisabled{}
-> [SuggestSafeHaskell]
TcRnDeprecatedModule{}
-> noHints
TcRnRedundantSourceImport{}
-> noHints
TcRnImportLookup (ImportLookupBad k _ is ie patsyns_enabled) ->
let mod_name = moduleName $ is_mod is
occ = rdrNameOcc $ ieName ie
in case k of
BadImportAvailVar -> [ImportSuggestion occ $ CouldRemoveTypeKeyword mod_name]
BadImportNotExported suggs -> suggs
BadImportAvailTyCon ex_ns ->
[useExtensionInOrderTo empty LangExt.ExplicitNamespaces | not ex_ns]
++ [ImportSuggestion occ $ CouldAddTypeKeyword mod_name]
BadImportAvailDataCon par -> [ImportSuggestion occ $ ImportDataCon (Just (mod_name, patsyns_enabled)) par]
BadImportNotExportedSubordinates{} -> noHints
TcRnImportLookup{}
-> noHints
TcRnUnusedImport{}
-> noHints
TcRnDuplicateDecls{}
-> noHints
TcRnPackageImportsDisabled
-> [suggestExtension LangExt.PackageImports]
TcRnIllegalDataCon{}
-> noHints
TcRnNestedForallsContexts{}
-> noHints
TcRnRedundantRecordWildcard
-> [SuggestRemoveRecordWildcard]
TcRnUnusedRecordWildcard{}
-> [SuggestRemoveRecordWildcard]
TcRnUnusedName{}
-> noHints
TcRnQualifiedBinder{}
-> noHints
TcRnTypeApplicationsDisabled ty_app
-> case ty_app of
TypeApplication {}
-> [suggestExtension LangExt.TypeApplications]
TypeApplicationInPattern {}
-> [suggestExtension LangExt.TypeAbstractions]
TcRnInvalidRecordField{}
-> noHints
TcRnTupleTooLarge{}
-> noHints
TcRnCTupleTooLarge{}
-> noHints
TcRnIllegalInferredTyVars{}
-> noHints
TcRnAmbiguousName{}
-> noHints
TcRnBindingNameConflict{}
-> noHints
TcRnNonCanonicalDefinition reason _
-> suggestNonCanonicalDefinition reason
TcRnDefaultedExceptionContext _
-> noHints
TcRnImplicitImportOfPrelude {}
-> noHints
TcRnMissingMain {}
-> noHints
TcRnGhciUnliftedBind {}
-> noHints
TcRnGhciMonadLookupFail {}
-> noHints
TcRnMissingRoleAnnotation{}
-> noHints
TcRnIllegalInvisTyVarBndr{}
-> [suggestExtension LangExt.TypeAbstractions]
TcRnIllegalWildcardTyVarBndr{}
-> [suggestExtension LangExt.TypeAbstractions]
TcRnDeprecatedInvisTyArgInConPat{}
-> [suggestExtension LangExt.TypeAbstractions]
TcRnInvalidInvisTyVarBndr{}
-> noHints
TcRnInvisBndrWithoutSig name _
-> [SuggestAddStandaloneKindSignature name]
TcRnImplicitRhsQuantification kv
-> [SuggestBindTyVarOnLhs (unLoc kv)]
TcRnPatersonCondFailure{}
-> [suggestExtension LangExt.UndecidableInstances]
TcRnIllformedTypePattern{}
-> noHints
TcRnIllegalTypePattern{}
-> noHints
TcRnIllformedTypeArgument{}
-> noHints
TcRnIllegalTypeExpr{}
-> noHints
TcRnInvalidDefaultedTyVar{}
-> noHints
TcRnNamespacedWarningPragmaWithoutFlag{}
-> [suggestExtension LangExt.ExplicitNamespaces]
TcRnIllegalInvisibleTypePattern{}
-> [suggestExtension LangExt.TypeAbstractions]
TcRnInvisPatWithNoForAll{}
-> noHints
TcRnNamespacedFixitySigWithoutFlag{}
-> [suggestExtension LangExt.ExplicitNamespaces]
TcRnOutOfArityTyVar{}
-> noHints
TcRnMisplacedInvisPat{}
-> noHints
TcRnUnexpectedTypeSyntaxInTerms syntax
-> [suggestExtension (typeSyntaxExtension syntax)]
diagnosticCode = constructorCode
note :: SDoc -> SDoc
note note = "Note" <> colon <+> note <> dot
-- | Change [x] to "x", [x, y] to "x and y", [x, y, z] to "x, y, and z",
-- and so on. The `and` stands for any `conjunction`, which is passed in.
commafyWith :: SDoc -> [SDoc] -> [SDoc]
commafyWith _ [] = []
commafyWith _ [x] = [x]
commafyWith conjunction [x, y] = [x <+> conjunction <+> y]
commafyWith conjunction xs = addConjunction $ punctuate comma xs
where addConjunction [x, y] = [x, conjunction, y]
addConjunction (x : xs) = x : addConjunction xs
addConjunction _ = panic "commafyWith expected 2 or more elements"
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
-> Bool
-> DecoratedSDoc
-> DecoratedSDoc
messageWithInfoDiagnosticMessage unit_state ErrInfo{..} show_ctxt important =
let err_info' = map (pprWithUnitState unit_state) ([errInfoContext | show_ctxt] ++ [errInfoSupplementary])
in (mapDecoratedSDoc (pprWithUnitState unit_state) important) `unionDecoratedSDoc`
mkDecorated err_info'
messageWithHsDocContext :: TcRnMessageOpts -> HsDocContext -> DecoratedSDoc -> DecoratedSDoc
messageWithHsDocContext opts ctxt main_msg = do
if tcOptsShowContext opts
then main_msg `unionDecoratedSDoc` ctxt_msg
else main_msg
where
ctxt_msg = mkSimpleDecorated (inHsDocContext ctxt)
dodgy_msg :: Outputable ie => SDoc -> GlobalRdrElt -> ie -> SDoc
dodgy_msg kind tc ie
= vcat [ text "The" <+> kind <+> text "item" <+> quotes (ppr ie) <+> text "suggests that"
, quotes (ppr $ greName tc) <+> text "has" <+> sep rest ]
where
rest :: [SDoc]
rest =
case greInfo tc of
IAmTyCon ClassFlavour
-> [ text "(in-scope) class methods or associated types" <> comma
, text "but it has none" ]
IAmTyCon _
-> [ text "(in-scope) constructors or record fields" <> comma
, text "but it has none" ]
_ -> [ text "children" <> comma
, text "but it is not a type constructor or a class" ]
dodgy_msg_insert :: GlobalRdrElt -> IE GhcRn
dodgy_msg_insert tc_gre = IEThingAll (Nothing, noAnn) ii Nothing
where
ii = noLocA (IEName noExtField $ noLocA $ greName tc_gre)
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) = tidyOpenTypeX emptyTidyEnv ty
tidy_ki = tidyType tidy_env (typeKind ty)
pprField :: (FieldLabelString, TcType) -> SDoc
pprField (f,ty) = ppr f <+> dcolon <+> ppr ty
pprRecordFieldPart :: RecordFieldPart -> SDoc
pprRecordFieldPart = \case
RecordFieldDecl {} -> text "declaration"
RecordFieldConstructor{} -> text "construction"
RecordFieldPattern{} -> text "pattern"
RecordFieldUpdate -> text "update"
ppr_opfix :: (OpName, Fixity) -> SDoc
ppr_opfix (op, fixity) = pp_op <+> brackets (ppr fixity)
where
pp_op | NegateOp <- op = text "prefix `-'"
| otherwise = quotes (ppr op)
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 ]
-- | What warning flags are associated with the given missing signature?
missingSignatureWarningFlags :: MissingSignature -> Exported -> NonEmpty WarningFlag
missingSignatureWarningFlags (MissingTopLevelBindingSig {}) exported
-- We prefer "bigger" warnings first: #14794
--
-- See Note [Warnings controlled by multiple flags]
= Opt_WarnMissingSignatures :|
[ Opt_WarnMissingExportedSignatures | IsExported == exported ]
missingSignatureWarningFlags (MissingPatSynSig {}) exported
= Opt_WarnMissingPatternSynonymSignatures :|
[ Opt_WarnMissingExportedPatternSynonymSignatures | IsExported == exported ]
missingSignatureWarningFlags (MissingTyConKindSig ty_con _) _
= Opt_WarnMissingKindSignatures :| [Opt_WarnMissingPolyKindSignatures | isForAllTy_invis_ty (tyConKind ty_con) ]
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)
lookupInstanceErrDiagnosticMessage :: Class
-> [Type]
-> LookupInstanceErrReason
-> SDoc
lookupInstanceErrDiagnosticMessage cls tys = \case
LookupInstErrNotExact
-> text "Not an exact match (i.e., some variables get instantiated)"
LookupInstErrFlexiVar
-> text "flexible type variable:" <+> (ppr $ mkTyConApp (classTyCon cls) tys)
LookupInstErrNotFound
-> text "instance not found" <+> (ppr $ mkTyConApp (classTyCon cls) tys)
{- *********************************************************************
* *
Outputable SolverReportErrCtxt (for debugging)
* *
**********************************************************************-}
instance Outputable SolverReportErrCtxt where
ppr (CEC { cec_binds = bvar
, cec_defer_type_errors = dte
, cec_expr_holes = eh
, cec_type_holes = th
, cec_out_of_scope_holes = osh
, cec_warn_redundant = wr
, cec_expand_syns = es
, cec_suppress = sup })
= text "CEC" <+> braces (vcat
[ text "cec_binds" <+> equals <+> ppr bvar
, text "cec_defer_type_errors" <+> equals <+> ppr dte
, text "cec_expr_holes" <+> equals <+> ppr eh
, text "cec_type_holes" <+> equals <+> ppr th
, text "cec_out_of_scope_holes" <+> equals <+> ppr osh
, text "cec_warn_redundant" <+> equals <+> ppr wr
, text "cec_expand_syns" <+> equals <+> ppr es
, text "cec_suppress" <+> equals <+> ppr sup ])
{- *********************************************************************
* *
Outputting TcSolverReportMsg errors
* *
**********************************************************************-}
-- | Pretty-print a 'SolverReportWithCtxt', containing a 'TcSolverReportMsg'
-- with its enclosing 'SolverReportErrCtxt'.
pprSolverReportWithCtxt :: SolverReportWithCtxt -> SDoc
pprSolverReportWithCtxt (SolverReportWithCtxt { reportContext = ctxt, reportContent = msg })
= pprTcSolverReportMsg ctxt msg
-- | Pretty-print a 'TcSolverReportMsg', with its enclosing 'SolverReportErrCtxt'.
pprTcSolverReportMsg :: SolverReportErrCtxt -> TcSolverReportMsg -> SDoc
pprTcSolverReportMsg _ (BadTelescope telescope skols) =
hang (text "These kind and type variables:" <+> ppr telescope $$
text "are out of dependency order. Perhaps try this ordering:")
2 (pprTyVars sorted_tvs)
where
sorted_tvs = scopedSort skols
pprTcSolverReportMsg _ (UserTypeError ty) =
pprUserTypeErrorTy ty
pprTcSolverReportMsg _ (UnsatisfiableError ty) =
pprUserTypeErrorTy ty
pprTcSolverReportMsg ctxt (ReportHoleError hole err) =
pprHoleError ctxt hole err
pprTcSolverReportMsg ctxt
(CannotUnifyVariable
{ mismatchMsg = msg
, cannotUnifyReason = reason })
= pprMismatchMsg ctxt msg
$$ pprCannotUnifyVariableReason ctxt reason
pprTcSolverReportMsg ctxt
(Mismatch
{ mismatchMsg = mismatch_msg
, mismatchTyVarInfo = tv_info
, mismatchAmbiguityInfo = ambig_infos
, mismatchCoercibleInfo = coercible_info })
= vcat ([ pprMismatchMsg ctxt mismatch_msg
, maybe empty (pprTyVarInfo ctxt) tv_info
, maybe empty pprCoercibleMsg coercible_info ]
++ (map pprAmbiguityInfo ambig_infos))
pprTcSolverReportMsg _ (FixedRuntimeRepError frr_origs) =
vcat (map make_msg frr_origs)
where
-- Assemble the error message: pair up each origin with the corresponding type, e.g.
-- • FixedRuntimeRep origin msg 1 ...
-- a :: TYPE r1
-- • FixedRuntimeRep origin msg 2 ...
-- b :: TYPE r2
make_msg :: FixedRuntimeRepErrorInfo -> SDoc
make_msg (FRR_Info { frr_info_origin =
FixedRuntimeRepOrigin
{ frr_type = ty
, frr_context = frr_ctxt }
, frr_info_not_concrete =
mb_not_conc }) =
-- Add bullet points if there is more than one error.
(if length frr_origs > 1 then (bullet <+>) else id) $
vcat [ sep [ pprFixedRuntimeRepContext frr_ctxt
, text "does not have a fixed runtime representation." ]
, type_printout ty
, case mb_not_conc of
Nothing -> empty
Just (conc_tv, not_conc) ->
unsolved_concrete_eq_explanation conc_tv not_conc ]
-- Don't print out the type (only the kind), if the type includes
-- a confusing cast, unless the user passed -fprint-explicit-coercions.
--
-- Example:
--
-- In T20363, we have a representation-polymorphism error with a type
-- of the form
--
-- ( (# #) |> co ) :: TYPE NilRep
--
-- where NilRep is a nullary type family application which reduces to TupleRep '[].
-- We prefer avoiding showing the cast to the user, but we also don't want to
-- print the confusing:
--
-- (# #) :: TYPE NilRep
--
-- So in this case we simply don't print the type, only the kind.
confusing_cast :: Type -> Bool
confusing_cast ty =
case ty of
CastTy inner_ty _
-- A confusing cast is one that is responsible
-- for a representation-polymorphism error.
-> isConcreteType (typeKind inner_ty)
_ -> False
type_printout :: Type -> SDoc
type_printout ty =
sdocOption sdocPrintExplicitCoercions $ \ show_coercions ->
if confusing_cast ty && not show_coercions
then vcat [ text "Its kind is:"
, nest 2 $ pprWithTYPE (typeKind ty)
, text "(Use -fprint-explicit-coercions to see the full type.)" ]
else vcat [ text "Its type is:"
, nest 2 $ ppr ty <+> dcolon <+> pprWithTYPE (typeKind ty) ]
unsolved_concrete_eq_explanation :: TcTyVar -> Type -> SDoc
unsolved_concrete_eq_explanation tv not_conc =
text "Cannot unify" <+> quotes (ppr not_conc)
<+> text "with the type variable" <+> quotes (ppr tv)
$$ text "because the former is not a concrete" <+> what <> dot
where
ki = tyVarKind tv
what :: SDoc
what
| isRuntimeRepTy ki
= quotes (text "RuntimeRep")
| isLevityTy ki
= quotes (text "Levity")
| otherwise
= text "type"
pprTcSolverReportMsg _ (BlockedEquality item) =
vcat [ hang (text "Cannot use equality for substitution:")
2 (ppr (errorItemPred item))
, text "Doing so would be ill-kinded." ]
pprTcSolverReportMsg _ (ExpectingMoreArguments n thing) =
text "Expecting" <+> speakN (abs n) <+>
more <+> quotes (ppr thing)
where
more
| n == 1 = text "more argument to"
| otherwise = text "more arguments to" -- n > 1
pprTcSolverReportMsg ctxt (UnboundImplicitParams (item :| items)) =
let givens = getUserGivens ctxt
in if null givens
then addArising (errorItemCtLoc item) $
sep [ text "Unbound implicit parameter" <> plural preds
, nest 2 (pprParendTheta preds) ]
else pprMismatchMsg ctxt (CouldNotDeduce givens (item :| items) Nothing)
where
preds = map errorItemPred (item : items)
pprTcSolverReportMsg _ (AmbiguityPreventsSolvingCt item ambigs) =
pprAmbiguityInfo (Ambiguity True ambigs) <+>
pprArising (errorItemCtLoc item) $$
text "prevents the constraint" <+> quotes (pprParendType $ errorItemPred item)
<+> text "from being solved."
pprTcSolverReportMsg ctxt@(CEC {cec_encl = implics})
(CannotResolveInstance item unifiers candidates imp_errs suggs binds)
=
vcat
[ no_inst_msg
, nest 2 extra_note
, mb_patsyn_prov `orElse` empty
, ppWhen (has_ambigs && not (null unifiers && null useful_givens))
(vcat [ ppUnless lead_with_ambig $
pprAmbiguityInfo (Ambiguity False (ambig_kvs, ambig_tvs))
, pprRelevantBindings binds
, potential_msg ])
, ppWhen (isNothing mb_patsyn_prov) $
-- Don't suggest fixes for the provided context of a pattern
-- synonym; the right fix is to bind more in the pattern
show_fixes (ctxtFixes has_ambigs pred implics
++ drv_fixes ++ naked_sc_fixes)
, ppWhen (not (null candidates))
(hang (text "There are instances for similar types:")
2 (vcat (map ppr candidates)))
-- See Note [Report candidate instances]
, vcat $ map ppr imp_errs
, vcat $ map ppr suggs ]
where
orig = errorItemOrigin item
pred = errorItemPred item
(clas, tys) = getClassPredTys pred
-- See Note [Highlighting ambiguous type variables] in GHC.Tc.Errors
(ambig_kvs, ambig_tvs) = ambigTkvsOfTy pred
ambigs = ambig_kvs ++ ambig_tvs
has_ambigs = not (null ambigs)
useful_givens = discardProvCtxtGivens orig (getUserGivensFromImplics implics)
-- useful_givens are the enclosing implications with non-empty givens,
-- modulo the horrid discardProvCtxtGivens
lead_with_ambig = not (null ambigs)
&& not (any isRuntimeUnkSkol ambigs)
&& not (null unifiers)
&& null useful_givens
no_inst_msg :: SDoc
no_inst_msg
| lead_with_ambig
= pprTcSolverReportMsg ctxt $ AmbiguityPreventsSolvingCt item (ambig_kvs, ambig_tvs)
| otherwise
= pprMismatchMsg ctxt $ CouldNotDeduce useful_givens (item :| []) Nothing
-- Report "potential instances" only when the constraint arises
-- directly from the user's use of an overloaded function
want_potential (TypeEqOrigin {}) = False
want_potential _ = True
potential_msg
= ppWhen (not (null unifiers) && want_potential orig) $
potential_hdr $$
potentialInstancesErrMsg (PotentialInstances { matches = [], unifiers })
potential_hdr
= ppWhen lead_with_ambig $
text "Probable fix: use a type annotation to specify what"
<+> pprQuotedList ambig_tvs <+> text "should be."
mb_patsyn_prov :: Maybe SDoc
mb_patsyn_prov
| not lead_with_ambig
, ProvCtxtOrigin PSB{ psb_def = L _ pat } <- orig
= Just (vcat [ text "In other words, a successful match on the pattern"
, nest 2 $ ppr pat
, text "does not provide the constraint" <+> pprParendType pred ])
| otherwise = Nothing
extra_note | any isFunTy (filterOutInvisibleTypes (classTyCon clas) tys)
= text "(maybe you haven't applied a function to enough arguments?)"
| className clas == typeableClassName -- Avoid mysterious "No instance for (Typeable T)
, [_,ty] <- tys -- Look for (Typeable (k->*) (T k))
, Just (tc,_) <- tcSplitTyConApp_maybe ty
, not (isTypeFamilyTyCon tc)
= hang (text "GHC can't yet do polykinded")
2 (text "Typeable" <+>
parens (ppr ty <+> dcolon <+> ppr (typeKind ty)))
| otherwise
= empty
drv_fixes = case orig of
DerivClauseOrigin -> [drv_fix False]
StandAloneDerivOrigin -> [drv_fix True]
DerivOriginDC _ _ standalone -> [drv_fix standalone]
DerivOriginCoerce _ _ _ standalone -> [drv_fix standalone]
_ -> []
drv_fix standalone_wildcard
| standalone_wildcard
= text "fill in the wildcard constraint yourself"
| otherwise
= hang (text "use a standalone 'deriving instance' declaration,")
2 (text "so you can specify the instance context yourself")
-- naked_sc_fix: try to produce a helpful error message for
-- superclass constraints caught by the subtleties described by
-- Note [Recursive superclasses] in GHC.TyCl.Instance
naked_sc_fixes
| ScOrigin _ NakedSc <- orig -- A superclass wanted with no instance decls used yet
, any non_tyvar_preds useful_givens -- Some non-tyvar givens
= [vcat [ text "If the constraint looks soluble from a superclass of the instance context,"
, text "read 'Undecidable instances and loopy superclasses' in the user manual" ]]
| otherwise = []
non_tyvar_preds :: UserGiven -> Bool
non_tyvar_preds = any non_tyvar_pred . ic_given
non_tyvar_pred :: EvVar -> Bool
-- Tells if the Given is of form (C ty1 .. tyn), where the tys are not all tyvars
non_tyvar_pred given = case getClassPredTys_maybe (idType given) of
Just (_, tys) -> not (all isTyVarTy tys)
Nothing -> False
pprTcSolverReportMsg (CEC {cec_encl = implics}) (OverlappingInstances item matches unifiers) =
vcat
[ addArising ct_loc $
(text "Overlapping instances for"
<+> pprType (mkClassPred clas tys))
, ppUnless (null matching_givens) $
sep [text "Matching givens (or their superclasses):"
, nest 2 (vcat matching_givens)]
, potentialInstancesErrMsg
(PotentialInstances { matches = NE.toList matches, unifiers })
, ppWhen (null matching_givens && null (NE.tail matches) && null unifiers) $
-- Intuitively, some given matched the wanted in their
-- flattened or rewritten (from given equalities) form
-- but the matcher can't figure that out because the
-- constraints are non-flat and non-rewritten so we
-- simply report back the whole given
-- context. Accelerate Smart.hs showed this problem.
sep [ text "There exists a (perhaps superclass) match:"
, nest 2 (vcat (pp_givens useful_givens))]
, ppWhen (null $ NE.tail matches) $
parens (vcat [ ppUnless (null tyCoVars) $
text "The choice depends on the instantiation of" <+>
quotes (pprWithCommas ppr tyCoVars)
, ppUnless (null famTyCons) $
if (null tyCoVars)
then
text "The choice depends on the result of evaluating" <+>
quotes (pprWithCommas ppr famTyCons)
else
text "and the result of evaluating" <+>
quotes (pprWithCommas ppr famTyCons)
, ppWhen (null (matching_givens)) $
vcat [ text "To pick the first instance above, use IncoherentInstances"
, text "when compiling the other instance declarations"]
])]
where
ct_loc = errorItemCtLoc item
orig = ctLocOrigin ct_loc
pred = errorItemPred item
(clas, tys) = getClassPredTys pred
tyCoVars = tyCoVarsOfTypesList tys
famTyCons = filter isFamilyTyCon $ concatMap (nonDetEltsUniqSet . tyConsOfType) tys
useful_givens = discardProvCtxtGivens orig (getUserGivensFromImplics implics)
matching_givens = mapMaybe matchable useful_givens
matchable implic@(Implic { ic_given = evvars, ic_info = skol_info })
= case ev_vars_matching of
[] -> Nothing
_ -> Just $ hang (pprTheta ev_vars_matching)
2 (sep [ text "bound by" <+> ppr skol_info
, text "at" <+>
ppr (getCtLocEnvLoc (ic_env implic)) ])
where ev_vars_matching = [ pred
| ev_var <- evvars
, let pred = evVarPred ev_var
, any can_match (pred : transSuperClasses pred) ]
can_match pred
= case getClassPredTys_maybe pred of
Just (clas', tys') -> clas' == clas
&& isJust (tcMatchTys tys tys')
Nothing -> False
pprTcSolverReportMsg _ (UnsafeOverlap item match unsafe_overlapped) =
vcat [ addArising ct_loc (text "Unsafe overlapping instances for"
<+> pprType (mkClassPred clas tys))
, sep [text "The matching instance is:",
nest 2 (pprInstance match)]
, vcat [ text "It is compiled in a Safe module and as such can only"
, text "overlap instances from the same module, however it"
, text "overlaps the following instances from different" <+>
text "modules:"
, nest 2 (vcat [pprInstances $ NE.toList unsafe_overlapped])
]
]
where
ct_loc = errorItemCtLoc item
pred = errorItemPred item
(clas, tys) = getClassPredTys pred
pprCannotUnifyVariableReason :: SolverReportErrCtxt -> CannotUnifyVariableReason -> SDoc
pprCannotUnifyVariableReason ctxt (CannotUnifyWithPolytype item tv1 ty2 mb_tv_info) =
vcat [ (if isSkolemTyVar tv1
then text "Cannot equate type variable"
else text "Cannot instantiate unification variable")
<+> quotes (ppr tv1)
, hang (text "with a" <+> what <+> text "involving polytypes:") 2 (ppr ty2)
, maybe empty (pprTyVarInfo ctxt) mb_tv_info ]
where
what = text $ levelString $
ctLocTypeOrKind_maybe (errorItemCtLoc item) `orElse` TypeLevel
pprCannotUnifyVariableReason _ (SkolemEscape item implic esc_skols) =
let
esc_doc = sep [ text "because" <+> what <+> text "variable" <> plural esc_skols
<+> pprQuotedList esc_skols
, text "would escape" <+>
if isSingleton esc_skols then text "its scope"
else text "their scope" ]
in
vcat [ nest 2 $ esc_doc
, sep [ (if isSingleton esc_skols
then text "This (rigid, skolem)" <+>
what <+> text "variable is"
else text "These (rigid, skolem)" <+>
what <+> text "variables are")
<+> text "bound by"
, nest 2 $ ppr (ic_info implic)
, nest 2 $ text "at" <+>
ppr (getCtLocEnvLoc (ic_env implic)) ] ]
where
what = text $ levelString $
ctLocTypeOrKind_maybe (errorItemCtLoc item) `orElse` TypeLevel
pprCannotUnifyVariableReason ctxt
(OccursCheck
{ occursCheckInterestingTyVars = interesting_tvs
, occursCheckAmbiguityInfos = ambig_infos })
= ppr_interesting_tyVars interesting_tvs
$$ vcat (map pprAmbiguityInfo ambig_infos)
where
ppr_interesting_tyVars [] = empty
ppr_interesting_tyVars (tv:tvs) =
hang (text "Type variable kinds:") 2 $
vcat (map (tyvar_binding . tidyTyCoVarOcc (cec_tidy ctxt))
(tv:tvs))
tyvar_binding tyvar = ppr tyvar <+> dcolon <+> ppr (tyVarKind tyvar)
pprCannotUnifyVariableReason ctxt (DifferentTyVars tv_info)
= pprTyVarInfo ctxt tv_info
pprCannotUnifyVariableReason ctxt (RepresentationalEq tv_info mb_coercible_msg)
= pprTyVarInfo ctxt tv_info
$$ maybe empty pprCoercibleMsg mb_coercible_msg
pprUntouchableVariable :: TcTyVar -> Implication -> SDoc
pprUntouchableVariable tv (Implic { ic_given = given, ic_info = skol_info, ic_env = env })
= sep [ quotes (ppr tv) <+> text "is untouchable"
, nest 2 $ text "inside the constraints:" <+> pprEvVarTheta given
, nest 2 $ text "bound by" <+> ppr skol_info
, nest 2 $ text "at" <+> ppr (getCtLocEnvLoc env) ]
pprMismatchMsg :: SolverReportErrCtxt -> MismatchMsg -> SDoc
pprMismatchMsg ctxt
(BasicMismatch { mismatch_ea = ea
, mismatch_item = item
, mismatch_ty1 = ty1 -- Expected
, mismatch_ty2 = ty2 -- Actual
, mismatch_whenMatching = mb_match_txt
, mismatch_mb_same_occ = same_occ_info })
= vcat [ addArising (errorItemCtLoc item) msg
, ea_extra
, maybe empty (pprWhenMatching ctxt) mb_match_txt
, maybe empty pprSameOccInfo same_occ_info ]
where
msg
| (isLiftedRuntimeRep ty1 && isUnliftedRuntimeRep ty2) ||
(isLiftedRuntimeRep ty2 && isUnliftedRuntimeRep ty1) ||
(isLiftedLevity ty1 && isUnliftedLevity ty2) ||
(isLiftedLevity ty2 && isUnliftedLevity ty1)
= text "Couldn't match a lifted type with an unlifted type"
| isAtomicTy ty1 || isAtomicTy ty2
= -- Print with quotes
sep [ text herald1 <+> quotes (ppr ty1)
, nest padding $
text herald2 <+> quotes (ppr ty2) ]
| otherwise
= -- Print with vertical layout
vcat [ text herald1 <> colon <+> ppr ty1
, nest padding $
text herald2 <> colon <+> ppr ty2 ]
herald1 = conc [ "Couldn't match"
, if is_repr then "representation of" else ""
, if want_ea then "expected" else ""
, what ]
herald2 = conc [ "with"
, if is_repr then "that of" else ""
, if want_ea then ("actual " ++ what) else "" ]
padding = length herald1 - length herald2
(want_ea, ea_extra)
= case ea of
NoEA -> (False, empty)
EA mb_extra -> (True , maybe empty (pprExpectedActualInfo ctxt) mb_extra)
is_repr = case errorItemEqRel item of { ReprEq -> True; NomEq -> False }
what = levelString (ctLocTypeOrKind_maybe (errorItemCtLoc item) `orElse` TypeLevel)
conc :: [String] -> String
conc = foldr1 add_space
add_space :: String -> String -> String
add_space s1 s2 | null s1 = s2
| null s2 = s1
| otherwise = s1 ++ (' ' : s2)
pprMismatchMsg _
(KindMismatch { kmismatch_what = thing
, kmismatch_expected = exp
, kmismatch_actual = act })
= hang (text "Expected" <+> kind_desc <> comma)
2 (text "but" <+> quotes (ppr thing) <+> text "has kind" <+>
quotes (ppr act))
where
kind_desc | isConstraintLikeKind exp = text "a constraint"
| Just arg <- kindRep_maybe exp -- TYPE t0
, tcIsTyVarTy arg = sdocOption sdocPrintExplicitRuntimeReps $ \case
True -> text "kind" <+> quotes (ppr exp)
False -> text "a type"
| otherwise = text "kind" <+> quotes (ppr exp)
pprMismatchMsg ctxt
(TypeEqMismatch { teq_mismatch_item = item
, teq_mismatch_ty1 = ty1 -- These types are the actual types
, teq_mismatch_ty2 = ty2 -- that don't match; may be swapped
, teq_mismatch_expected = exp -- These are the context of
, teq_mismatch_actual = act -- the mis-match
, teq_mismatch_what = mb_thing
, teq_mb_same_occ = mb_same_occ })
= addArising ct_loc $
pprWithInvisibleBitsWhen ppr_invis_bits msg
$$ maybe empty pprSameOccInfo mb_same_occ
where
msg | Just (torc, rep) <- sORTKind_maybe exp
= msg_for_exp_sort torc rep
| Just nargs_msg <- num_args_msg
, Right ea_msg <- mk_ea_msg ctxt (Just item) level orig
= nargs_msg $$ pprMismatchMsg ctxt ea_msg
| ea_looks_same ty1 ty2 exp act
, Right ea_msg <- mk_ea_msg ctxt (Just item) level orig
= pprMismatchMsg ctxt ea_msg
| otherwise
= bale_out_msg
-- bale_out_msg: the mismatched types are /inside/ exp and act
bale_out_msg = vcat errs
where
errs = case mk_ea_msg ctxt Nothing level orig of
Left ea_info -> pprMismatchMsg ctxt mismatch_err
: map (pprExpectedActualInfo ctxt) ea_info
Right ea_err -> [ pprMismatchMsg ctxt mismatch_err
, pprMismatchMsg ctxt ea_err ]
mismatch_err = mkBasicMismatchMsg NoEA item ty1 ty2
-- 'expected' is (TYPE rep) or (CONSTRAINT rep)
msg_for_exp_sort exp_torc exp_rep
| Just (act_torc, act_rep) <- sORTKind_maybe act
= -- (TYPE exp_rep) ~ (CONSTRAINT act_rep) etc
msg_torc_torc act_torc act_rep
| otherwise
= -- (TYPE _) ~ Bool, etc
maybe_num_args_msg $$
sep [ text "Expected a" <+> ppr_torc exp_torc <> comma
, text "but" <+> case mb_thing of
Nothing -> text "found something with kind"
Just thing -> quotes (ppr thing) <+> text "has kind"
, quotes (pprWithTYPE act) ]
where
msg_torc_torc act_torc act_rep
| exp_torc == act_torc
= msg_same_torc act_torc act_rep
| otherwise
= sep [ text "Expected a" <+> ppr_torc exp_torc <> comma
, text "but" <+> case mb_thing of
Nothing -> text "found a"
Just thing -> quotes (ppr thing) <+> text "is a"
<+> ppr_torc act_torc ]
msg_same_torc act_torc act_rep
| Just exp_doc <- describe_rep exp_rep
, Just act_doc <- describe_rep act_rep
= sep [ text "Expected" <+> exp_doc <+> ppr_torc exp_torc <> comma
, text "but" <+> case mb_thing of
Just thing -> quotes (ppr thing) <+> text "is"
Nothing -> text "got"
<+> act_doc <+> ppr_torc act_torc ]
msg_same_torc _ _ = bale_out_msg
ct_loc = errorItemCtLoc item
orig = errorItemOrigin item
level = ctLocTypeOrKind_maybe ct_loc `orElse` TypeLevel
ppr_invis_bits = shouldPprWithInvisibleBits ty1 ty2 orig
num_args_msg = case level of
KindLevel
| not (isMetaTyVarTy exp) && not (isMetaTyVarTy act)
-- if one is a meta-tyvar, then it's possible that the user
-- has asked for something impredicative, and we couldn't unify.
-- Don't bother with counting arguments.
-> let n_act = count_args act
n_exp = count_args exp in
case n_act - n_exp of
n | n > 0 -- we don't know how many args there are, so don't
-- recommend removing args that aren't
, Just thing <- mb_thing
-> Just $ pprTcSolverReportMsg ctxt (ExpectingMoreArguments n thing)
_ -> Nothing
_ -> Nothing
maybe_num_args_msg = num_args_msg `orElse` empty
count_args ty = count isVisiblePiTyBinder $ fst $ splitPiTys ty
ppr_torc TypeLike = text "type";
ppr_torc ConstraintLike = text "constraint"
describe_rep :: RuntimeRepType -> Maybe SDoc
-- describe_rep IntRep = Just "an IntRep"
-- describe_rep (BoxedRep Lifted) = Just "a lifted"
-- etc
describe_rep rep
| Just (rr_tc, rr_args) <- splitRuntimeRep_maybe rep
= case rr_args of
[lev_ty] | rr_tc `hasKey` boxedRepDataConKey
, Just lev <- levityType_maybe lev_ty
-> case lev of
Lifted -> Just (text "a lifted")
Unlifted -> Just (text "a boxed unlifted")
[] | rr_tc `hasKey` tupleRepDataConTyConKey -> Just (text "a zero-bit")
| starts_with_vowel rr_occ -> Just (text "an" <+> text rr_occ)
| otherwise -> Just (text "a" <+> text rr_occ)
where
rr_occ = occNameString (getOccName rr_tc)
_ -> Nothing -- Must be TupleRep [r1..rn]
| otherwise = Nothing
starts_with_vowel (c:_) = c `elem` ("AEIOU" :: String)
starts_with_vowel [] = False
pprMismatchMsg ctxt (CouldNotDeduce useful_givens (item :| others) mb_extra)
= main_msg $$
case supplementary of
Left infos
-> vcat (map (pprExpectedActualInfo ctxt) infos)
Right other_msg
-> pprMismatchMsg ctxt other_msg
where
main_msg
| null useful_givens
= addArising ct_loc (no_instance_msg <+> missing)
| otherwise
= vcat (addArising ct_loc (no_deduce_msg <+> missing)
: pp_givens useful_givens)
supplementary = case mb_extra of
Nothing
-> Left []
Just (CND_Extra level ty1 ty2)
-> mk_supplementary_ea_msg ctxt level ty1 ty2 orig
ct_loc = errorItemCtLoc item
orig = ctLocOrigin ct_loc
wanteds = map errorItemPred (item:others)
no_instance_msg =
case wanteds of
[wanted] | Just (tc, _) <- splitTyConApp_maybe wanted
-- Don't say "no instance" for a constraint such as "c" for a type variable c.
, isClassTyCon tc -> text "No instance for"
_ -> text "Could not solve:"
no_deduce_msg =
case wanteds of
[_wanted] -> text "Could not deduce"
_ -> text "Could not deduce:"
missing =
case wanteds of
[wanted] -> quotes (ppr wanted)
_ -> pprTheta wanteds
-- | Whether to print explicit kinds (with @-fprint-explicit-kinds@)
-- in an 'SDoc' when a type mismatch occurs to due invisible parts of the types.
-- See Note [Showing invisible bits of types in error messages]
--
-- This function first checks to see if the 'CtOrigin' argument is a
-- 'TypeEqOrigin'. If so, it first checks whether the equality is a visible
-- equality; if it's not, definitely print the kinds. Even if the equality is
-- a visible equality, check the expected/actual types to see if the types
-- have equal visible components. If the 'CtOrigin' is
-- not a 'TypeEqOrigin', fall back on the actual mismatched types themselves.
shouldPprWithInvisibleBits :: Type -> Type -> CtOrigin -> Bool
shouldPprWithInvisibleBits _ty1 _ty2 (TypeEqOrigin { uo_actual = act
, uo_expected = exp
, uo_visible = vis })
| not vis = True -- See tests T15870, T16204c
| otherwise = mayLookIdentical act exp -- See tests T9171, T9144.
shouldPprWithInvisibleBits ty1 ty2 _ct
= mayLookIdentical ty1 ty2
{- Note [Showing invisible bits of types in error messages]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
It can be terribly confusing to get an error message like (#9171)
Couldn't match expected type ‘GetParam Base (GetParam Base Int)’
with actual type ‘GetParam Base (GetParam Base Int)’
The reason may be that the kinds don't match up. Typically you'll get
more useful information, but not when it's as a result of ambiguity.
To mitigate this, when we find a type or kind mis-match:
* See if normally-visible parts of the type would make the two types
look different. This check is made by
`GHC.Core.TyCo.Compare.mayLookIdentical`
* If not, display the types with their normally-visible parts made visible,
by setting flags in the `SDocContext":
Specifically:
- Display kind arguments: sdocPrintExplicitKinds
- Don't default away runtime-reps: sdocPrintExplicitRuntimeReps,
which controls `GHC.Iface.Type.hideNonStandardTypes`
(NB: foralls are always printed by pprType, it turns out.)
As a result the above error message would instead be displayed as:
Couldn't match expected type
‘GetParam @* @k2 @* Base (GetParam @* @* @k2 Base Int)’
with actual type
‘GetParam @* @k20 @* Base (GetParam @* @* @k20 Base Int)’
Which makes it clearer that the culprit is the mismatch between `k2` and `k20`.
Another example of what goes wrong without this: #24553.
-}
{- *********************************************************************
* *
Displaying potential instances
* *
**********************************************************************-}
-- | Directly display the given matching and unifying instances,
-- with a header for each: `Matching instances`/`Potentially matching instances`.
pprPotentialInstances :: (ClsInst -> SDoc) -> PotentialInstances -> SDoc
pprPotentialInstances ppr_inst (PotentialInstances { matches, unifiers }) =
vcat
[ ppWhen (not $ null matches) $
text "Matching instance" <> plural matches <> colon $$
nest 2 (vcat (map ppr_inst matches))
, ppWhen (not $ null unifiers) $
(text "Potentially matching instance" <> plural unifiers <> colon) $$
nest 2 (vcat (map ppr_inst unifiers))
]
-- | Display a summary of available instances, omitting those involving
-- out-of-scope types, in order to explain why we couldn't solve a particular
-- constraint, e.g. due to instance overlap or out-of-scope types.
--
-- To directly display a collection of matching/unifying instances,
-- use 'pprPotentialInstances'.
potentialInstancesErrMsg :: PotentialInstances -> SDoc
-- See Note [Displaying potential instances]
potentialInstancesErrMsg potentials =
sdocOption sdocPrintPotentialInstances $ \print_insts ->
getPprStyle $ \sty ->
potentials_msg_with_options potentials print_insts sty
-- | Display a summary of available instances, omitting out-of-scope ones.
--
-- Use 'potentialInstancesErrMsg' to automatically set the pretty-printing
-- options.
potentials_msg_with_options :: PotentialInstances
-> Bool -- ^ Whether to print /all/ potential instances
-> PprStyle
-> SDoc
potentials_msg_with_options
(PotentialInstances { matches, unifiers })
show_all_potentials sty
| null matches && null unifiers
= empty
| null show_these_matches && null show_these_unifiers
= vcat [ not_in_scope_msg empty
, flag_hint ]
| otherwise
= vcat [ pprPotentialInstances
pprInstance -- print instance + location info
(PotentialInstances
{ matches = show_these_matches
, unifiers = show_these_unifiers })
, overlapping_but_not_more_specific_msg sorted_matches
, nest 2 $ vcat
[ ppWhen (n_in_scope_hidden > 0) $
text "...plus"
<+> speakNOf n_in_scope_hidden (text "other")
, ppWhen (not_in_scopes > 0) $
not_in_scope_msg (text "...plus")
, flag_hint ] ]
where
n_show_matches, n_show_unifiers :: Int
n_show_matches = 3
n_show_unifiers = 2
(in_scope_matches, not_in_scope_matches) = partition inst_in_scope matches
(in_scope_unifiers, not_in_scope_unifiers) = partition inst_in_scope unifiers
sorted_matches = sortBy fuzzyClsInstCmp in_scope_matches
sorted_unifiers = sortBy fuzzyClsInstCmp in_scope_unifiers
(show_these_matches, show_these_unifiers)
| show_all_potentials = (sorted_matches, sorted_unifiers)
| otherwise = (take n_show_matches sorted_matches
,take n_show_unifiers sorted_unifiers)
n_in_scope_hidden
= length sorted_matches + length sorted_unifiers
- length show_these_matches - length show_these_unifiers
-- "in scope" means that all the type constructors
-- are lexically in scope; these instances are likely
-- to be more useful
inst_in_scope :: ClsInst -> Bool
inst_in_scope cls_inst = nameSetAll name_in_scope $
orphNamesOfTypes (is_tys cls_inst)
name_in_scope name
| pretendNameIsInScope name
= True -- E.g. (->); see Note [pretendNameIsInScope] in GHC.Builtin.Names
| Just mod <- nameModule_maybe name
= qual_in_scope (qualName sty mod (nameOccName name))
| otherwise
= True
qual_in_scope :: QualifyName -> Bool
qual_in_scope NameUnqual = True
qual_in_scope (NameQual {}) = True
qual_in_scope _ = False
not_in_scopes :: Int
not_in_scopes = length not_in_scope_matches + length not_in_scope_unifiers
not_in_scope_msg herald =
hang (herald <+> speakNOf not_in_scopes (text "instance")
<+> text "involving out-of-scope types")
2 (ppWhen show_all_potentials $
pprPotentialInstances
pprInstanceHdr -- only print the header, not the instance location info
(PotentialInstances
{ matches = not_in_scope_matches
, unifiers = not_in_scope_unifiers
}))
flag_hint = ppUnless (show_all_potentials
|| (equalLength show_these_matches matches
&& equalLength show_these_unifiers unifiers)) $
text "(use -fprint-potential-instances to see them all)"
-- | Compute a message informing the user of any instances that are overlapped
-- but were not discarded because the instance overlapping them wasn't
-- strictly more specific.
overlapping_but_not_more_specific_msg :: [ClsInst] -> SDoc
overlapping_but_not_more_specific_msg insts
-- Only print one example of "overlapping but not strictly more specific",
-- to avoid information overload.
| overlap : _ <- overlapping_but_not_more_specific
= overlap_header $$ ppr_overlapping overlap
| otherwise
= empty
where
overlap_header :: SDoc
overlap_header
| [_] <- overlapping_but_not_more_specific
= text "An overlapping instance can only be chosen when it is strictly more specific."
| otherwise
= text "Overlapping instances can only be chosen when they are strictly more specific."
overlapping_but_not_more_specific :: [(ClsInst, ClsInst)]
overlapping_but_not_more_specific
= nubOrdBy (comparing (is_dfun . fst))
[ (overlapper, overlappee)
| these <- groupBy ((==) `on` is_cls_nm) insts
-- Take all pairs of distinct instances...
, one:others <- tails these -- if `these = [inst_1, inst_2, ...]`
, other <- others -- then we get pairs `(one, other) = (inst_i, inst_j)` with `i < j`
-- ... such that one instance in the pair overlaps the other...
, let mb_overlapping
| hasOverlappingFlag (overlapMode $ is_flag one)
|| hasOverlappableFlag (overlapMode $ is_flag other)
= [(one, other)]
| hasOverlappingFlag (overlapMode $ is_flag other)
|| hasOverlappableFlag (overlapMode $ is_flag one)
= [(other, one)]
| otherwise
= []
, (overlapper, overlappee) <- mb_overlapping
-- ... but the overlapper is not more specific than the overlappee.
, not (overlapper `more_specific_than` overlappee)
]
more_specific_than :: ClsInst -> ClsInst -> Bool
is1 `more_specific_than` is2
= isJust (tcMatchTys (is_tys is1) (is_tys is2))
ppr_overlapping :: (ClsInst, ClsInst) -> SDoc
ppr_overlapping (overlapper, overlappee)
= text "The first instance that follows overlaps the second, but is not more specific than it:"
$$ nest 2 (vcat $ map pprInstanceHdr [overlapper, overlappee])
{- Note [Displaying potential instances]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
When showing a list of instances for
- overlapping instances (show ones that match)
- no such instance (show ones that could match)
we want to give it a bit of structure. Here's the plan
* Say that an instance is "in scope" if all of the
type constructors it mentions are lexically in scope.
These are the ones most likely to be useful to the programmer.
* Show at most n_show in-scope instances,
and summarise the rest ("plus N others")
* Summarise the not-in-scope instances ("plus 4 not in scope")
* Add the flag -fshow-potential-instances which replaces the
summary with the full list
-}
{- *********************************************************************
* *
Outputting additional solver report information
* *
**********************************************************************-}
-- | Pretty-print an informational message, to accompany a 'TcSolverReportMsg'.
pprExpectedActualInfo :: SolverReportErrCtxt -> ExpectedActualInfo -> SDoc
pprExpectedActualInfo _ (ExpectedActual { ea_expected = exp, ea_actual = act }) =
vcat
[ text "Expected:" <+> ppr exp
, text " Actual:" <+> ppr act ]
pprExpectedActualInfo _
(ExpectedActualAfterTySynExpansion
{ ea_expanded_expected = exp
, ea_expanded_actual = act } )
= vcat
[ text "Type synonyms expanded:"
, text "Expected type:" <+> ppr exp
, text " Actual type:" <+> ppr act ]
pprCoercibleMsg :: CoercibleMsg -> SDoc
pprCoercibleMsg (UnknownRoles ty) =
note $ "We cannot know what roles the parameters to" <+> quotes (ppr ty) <+> "have;" $$
"we must assume that the role is nominal"
pprCoercibleMsg (TyConIsAbstract tc) =
note $ "The type constructor" <+> quotes (pprSourceTyCon tc) <+> "is abstract"
pprCoercibleMsg (OutOfScopeNewtypeConstructor tc dc) =
hang (text "The data constructor" <+> quotes (ppr $ dataConName dc))
2 (sep [ text "of newtype" <+> quotes (pprSourceTyCon tc)
, text "is not in scope" ])
pprWhenMatching :: SolverReportErrCtxt -> WhenMatching -> SDoc
pprWhenMatching ctxt (WhenMatching cty1 cty2 sub_o mb_sub_t_or_k) =
sdocOption sdocPrintExplicitCoercions $ \printExplicitCoercions ->
if printExplicitCoercions
|| not (cty1 `pickyEqType` cty2)
then vcat [ hang (text "When matching" <+> sub_whats)
2 (vcat [ ppr cty1 <+> dcolon <+>
ppr (typeKind cty1)
, ppr cty2 <+> dcolon <+>
ppr (typeKind cty2) ])
, supplementary ]
else text "When matching the kind of" <+> quotes (ppr cty1)
where
sub_t_or_k = mb_sub_t_or_k `orElse` TypeLevel
sub_whats = text (levelString sub_t_or_k) <> char 's'
supplementary =
case mk_supplementary_ea_msg ctxt sub_t_or_k cty1 cty2 sub_o of
Left infos -> vcat $ map (pprExpectedActualInfo ctxt) infos
Right msg -> pprMismatchMsg ctxt msg
pprTyVarInfo :: SolverReportErrCtxt -> TyVarInfo -> SDoc
pprTyVarInfo ctxt (TyVarInfo { thisTyVar = tv1, otherTy = mb_tv2, thisTyVarIsUntouchable = mb_implic })
= vcat [ mk_msg tv1
, maybe empty (pprUntouchableVariable tv1) mb_implic
, case mb_tv2 of { Nothing -> empty; Just tv2 -> mk_msg tv2 } ]
where
mk_msg tv = case tcTyVarDetails tv of
SkolemTv sk_info _ _ -> pprSkols ctxt [(getSkolemInfo sk_info, [tv])]
RuntimeUnk {} -> quotes (ppr tv) <+> text "is an interactive-debugger skolem"
MetaTv {} -> empty
pprAmbiguityInfo :: AmbiguityInfo -> SDoc
pprAmbiguityInfo (Ambiguity prepend_msg (ambig_kvs, ambig_tvs)) = msg
where
msg | any isRuntimeUnkSkol ambig_kvs -- See Note [Runtime skolems]
|| any isRuntimeUnkSkol ambig_tvs
= vcat [ text "Cannot resolve unknown runtime type"
<> plural ambig_tvs <+> pprQuotedList ambig_tvs
, text "Use :print or :force to determine these types"]
| not (null ambig_tvs)
= pp_ambig (text "type") ambig_tvs
| otherwise
= pp_ambig (text "kind") ambig_kvs
pp_ambig what tkvs
| prepend_msg -- "Ambiguous type variable 't0'"
= text "Ambiguous" <+> what <+> text "variable"
<> plural tkvs <+> pprQuotedList tkvs
| otherwise -- "The type variable 't0' is ambiguous"
= text "The" <+> what <+> text "variable" <> plural tkvs
<+> pprQuotedList tkvs <+> isOrAre tkvs <+> text "ambiguous"
pprAmbiguityInfo (NonInjectiveTyFam tc) =
note $ quotes (ppr tc) <+> text "is a non-injective type family"
pprSameOccInfo :: SameOccInfo -> SDoc
pprSameOccInfo (SameOcc same_pkg n1 n2) =
note (ppr_from same_pkg n1 $$ ppr_from same_pkg n2)
where
ppr_from same_pkg nm
| isGoodSrcSpan loc
= hang (quotes (ppr nm) <+> text "is defined at")
2 (ppr loc)
| otherwise -- Imported things have an UnhelpfulSrcSpan
= hang (quotes (ppr nm))
2 (sep [ text "is defined in" <+> quotes (ppr (moduleName mod))
, ppUnless (same_pkg || pkg == mainUnit) $
nest 4 $ text "in package" <+> quotes (ppr pkg) ])
where
pkg = moduleUnit mod
mod = nameModule nm
loc = nameSrcSpan nm
{- *********************************************************************
* *
Outputting HoleError messages
* *
**********************************************************************-}
pprHoleError :: SolverReportErrCtxt -> Hole -> HoleError -> SDoc
pprHoleError _ (Hole { hole_ty, hole_occ = rdr }) (OutOfScopeHole imp_errs _hints)
= out_of_scope_msg $$ vcat (map ppr imp_errs)
where
herald | isDataOcc (rdrNameOcc rdr) = text "Data constructor not in scope:"
| otherwise = text "Variable not in scope:"
out_of_scope_msg -- Print v :: ty only if the type has structure
| boring_type = hang herald 2 (ppr rdr)
| otherwise = hang herald 2 (pp_rdr_with_type rdr hole_ty)
boring_type = isTyVarTy hole_ty
pprHoleError ctxt (Hole { hole_ty, hole_occ}) (HoleError sort other_tvs hole_skol_info) =
vcat [ hole_msg
, tyvars_msg
, case sort of { ExprHole {} -> expr_hole_hint; _ -> type_hole_hint } ]
where
hole_msg = case sort of
ExprHole {} ->
hang (text "Found hole:")
2 (pp_rdr_with_type hole_occ hole_ty)
TypeHole ->
hang (text "Found type wildcard" <+> quotes (ppr hole_occ))
2 (text "standing for" <+> quotes pp_hole_type_with_kind)
ConstraintHole ->
hang (text "Found extra-constraints wildcard standing for")
2 (quotes $ pprType hole_ty) -- always kind Constraint
hole_kind = typeKind hole_ty
pp_hole_type_with_kind
| isLiftedTypeKind hole_kind
|| isCoVarType hole_ty -- Don't print the kind of unlifted
-- equalities (#15039)
= pprType hole_ty
| otherwise
= pprType hole_ty <+> dcolon <+> pprKind hole_kind
tyvars = tyCoVarsOfTypeList hole_ty
tyvars_msg = ppUnless (null tyvars) $
text "Where:" <+> (vcat (map loc_msg other_tvs)
$$ pprSkols ctxt hole_skol_info)
-- Coercion variables can be free in the
-- hole, via kind casts
expr_hole_hint -- Give hint for, say, f x = _x
| lengthFS (occNameFS (rdrNameOcc hole_occ)) > 1 -- Don't give this hint for plain "_"
= text "Or perhaps" <+> quotes (ppr hole_occ)
<+> text "is mis-spelled, or not in scope"
| otherwise
= empty
type_hole_hint
| ErrorWithoutFlag <- cec_type_holes ctxt
= text "To use the inferred type, enable PartialTypeSignatures"
| otherwise
= empty
loc_msg tv
| isTyVar tv
= case tcTyVarDetails tv of
MetaTv {} -> quotes (ppr tv) <+> text "is an ambiguous type variable"
_ -> empty -- Skolems dealt with already
| otherwise -- A coercion variable can be free in the hole type
= ppWhenOption sdocPrintExplicitCoercions $
quotes (ppr tv) <+> text "is a coercion variable"
pp_rdr_with_type :: RdrName -> Type -> SDoc
pp_rdr_with_type occ hole_ty = hang (pprPrefixOcc occ) 2 (dcolon <+> pprType hole_ty)
{- *********************************************************************
* *
Outputting ScopeError messages
* *
**********************************************************************-}
pprScopeError :: RdrName -> NotInScopeError -> SDoc
pprScopeError rdr_name scope_err =
case scope_err of
NotInScope ->
hang (text "Not in scope:")
2 (what <+> quotes (ppr rdr_name))
NotARecordField ->
hang (text "Not in scope:")
2 (text "record field" <+> quotes (ppr rdr_name))
NoExactName name ->
text "The Name" <+> quotes (ppr name) <+> text "is not in scope."
SameName gres ->
assertPpr (length gres >= 2) (text "pprScopeError SameName: fewer than 2 elements" $$ nest 2 (ppr gres))
$ hang (text "Same Name in multiple name-spaces:")
2 (vcat (map pp_one sorted_names))
where
sorted_names = sortBy (leftmost_smallest `on` nameSrcSpan)
$ map greName gres
pp_one name
= hang (pprNameSpace (occNameSpace (getOccName name))
<+> quotes (ppr name) <> comma)
2 (text "declared at:" <+> ppr (nameSrcLoc name))
MissingBinding thing _ ->
sep [ text "The" <+> thing
<+> text "for" <+> quotes (ppr rdr_name)
, nest 2 $ text "lacks an accompanying binding" ]
NoTopLevelBinding ->
hang (text "No top-level binding for")
2 (what <+> quotes (ppr rdr_name) <+> text "in this module")
UnknownSubordinate doc ->
quotes (ppr rdr_name) <+> text "is not a (visible)" <+> doc
NotInScopeTc env ->
vcat[text "GHC internal error:" <+> quotes (ppr rdr_name) <+>
text "is not in scope during type checking, but it passed the renamer",
text "tcl_env of environment:" <+> ppr env]
where
what = pprNonVarNameSpace (occNameSpace (rdrNameOcc rdr_name))
scopeErrorHints :: NotInScopeError -> [GhcHint]
scopeErrorHints scope_err =
case scope_err of
NotInScope -> noHints
NotARecordField -> noHints
NoExactName {} -> [SuggestDumpSlices]
SameName {} -> [SuggestDumpSlices]
MissingBinding _ hints -> hints
NoTopLevelBinding -> noHints
UnknownSubordinate {} -> noHints
NotInScopeTc _ -> noHints
tcSolverReportMsgHints :: SolverReportErrCtxt -> TcSolverReportMsg -> [GhcHint]
tcSolverReportMsgHints ctxt = \case
BadTelescope {}
-> noHints
UserTypeError {}
-> noHints
UnsatisfiableError {}
-> noHints
ReportHoleError hole err
-> holeErrorHints hole err
CannotUnifyVariable mismatch_msg rea
-> mismatchMsgHints ctxt mismatch_msg ++ cannotUnifyVariableHints rea
Mismatch { mismatchMsg = mismatch_msg }
-> mismatchMsgHints ctxt mismatch_msg
FixedRuntimeRepError {}
-> noHints
BlockedEquality {}
-> noHints
ExpectingMoreArguments {}
-> noHints
UnboundImplicitParams {}
-> noHints
AmbiguityPreventsSolvingCt {}
-> noHints
CannotResolveInstance {}
-> noHints
OverlappingInstances {}
-> noHints
UnsafeOverlap {}
-> noHints
mismatchMsgHints :: SolverReportErrCtxt -> MismatchMsg -> [GhcHint]
mismatchMsgHints ctxt msg =
maybeToList [ hint | (exp,act) <- mismatchMsg_ExpectedActuals msg
, hint <- suggestAddSig ctxt exp act ]
mismatchMsg_ExpectedActuals :: MismatchMsg -> Maybe (Type, Type)
mismatchMsg_ExpectedActuals = \case
BasicMismatch { mismatch_ty1 = exp, mismatch_ty2 = act } ->
Just (exp, act)
KindMismatch { kmismatch_expected = exp, kmismatch_actual = act } ->
Just (exp, act)
TypeEqMismatch { teq_mismatch_expected = exp, teq_mismatch_actual = act } ->
Just (exp,act)
CouldNotDeduce { cnd_extra = cnd_extra }
| Just (CND_Extra _ exp act) <- cnd_extra
-> Just (exp, act)
| otherwise
-> Nothing
holeErrorHints :: Hole -> HoleError -> [GhcHint]
holeErrorHints _hole = \case
OutOfScopeHole _ hints
-> hints
HoleError {}
-> noHints
cannotUnifyVariableHints :: CannotUnifyVariableReason -> [GhcHint]
cannotUnifyVariableHints = \case
CannotUnifyWithPolytype {}
-> noHints
OccursCheck {}
-> noHints
SkolemEscape {}
-> noHints
DifferentTyVars {}
-> noHints
RepresentationalEq {}
-> noHints
suggestAddSig :: SolverReportErrCtxt -> TcType -> TcType -> Maybe GhcHint
-- See Note [Suggest adding a type signature]
suggestAddSig ctxt ty1 _ty2
| bndr : bndrs <- inferred_bndrs
= Just $ SuggestAddTypeSignatures $ NamedBindings (bndr :| bndrs)
| otherwise
= Nothing
where
inferred_bndrs =
case getTyVar_maybe ty1 of
Just tv | isSkolemTyVar tv -> find (cec_encl ctxt) False tv
_ -> []
-- 'find' returns the binders of an InferSkol for 'tv',
-- provided there is an intervening implication with
-- ic_given_eqs /= NoGivenEqs (i.e. a GADT match)
find [] _ _ = []
find (implic:implics) seen_eqs tv
| tv `elem` ic_skols implic
, InferSkol prs <- ic_info implic
, seen_eqs
= map fst prs
| otherwise
= find implics (seen_eqs || ic_given_eqs implic /= NoGivenEqs) tv
{- Note [Suggest adding a type signature]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The OutsideIn algorithm rejects GADT programs that don't have a principal
type, and indeed some that do. Example:
data T a where
MkT :: Int -> T Int
f (MkT n) = n
Does this have type f :: T a -> a, or f :: T a -> Int?
The error that shows up tends to be an attempt to unify an
untouchable type variable. So suggestAddSig sees if the offending
type variable is bound by an *inferred* signature, and suggests
adding a declared signature instead.
More specifically, we suggest adding a type sig if we have p ~ ty, and
p is a skolem bound by an InferSkol. Those skolems were created from
unification variables in simplifyInfer. Why didn't we unify? It must
have been because of an intervening GADT or existential, making it
untouchable. Either way, a type signature would help. For GADTs, it
might make it typeable; for existentials the attempt to write a
signature will fail -- or at least will produce a better error message
next time
This initially came up in #8968, concerning pattern synonyms.
-}
{- *********************************************************************
* *
Outputting ImportError messages
* *
**********************************************************************-}
instance Outputable ImportError where
ppr err = note $ case err of
MissingModule mod_name -> "No module named" <+> quoted mod_name <+> "is imported"
ModulesDoNotExport mods occ_name
| mod NE.:| [] <- mods -> "The module" <+> quoted mod <+> "does not export" <+> quoted occ_name
| otherwise -> "Neither" <+> quotedListWithNor (map ppr $ NE.toList mods) <+> "export" <+> quoted occ_name
where
quoted :: Outputable a => a -> SDoc
quoted = quotes . ppr
{- *********************************************************************
* *
Suggested fixes for implication constraints
* *
**********************************************************************-}
-- TODO: these functions should use GhcHint instead.
show_fixes :: [SDoc] -> SDoc
show_fixes [] = empty
show_fixes (f:fs) = sep [ text "Possible fix:"
, nest 2 (vcat (f : map (text "or" <+>) fs))]
ctxtFixes :: Bool -> PredType -> [Implication] -> [SDoc]
ctxtFixes has_ambig_tvs pred implics
| not has_ambig_tvs
, isTyVarClassPred pred -- Don't suggest adding (Eq T) to the context, say
, (skol:skols) <- usefulContext implics pred
, let what | null skols
, SigSkol (PatSynCtxt {}) _ _ <- skol
= text "\"required\""
| otherwise
= empty
= [sep [ text "add" <+> pprParendType pred
<+> text "to the" <+> what <+> text "context of"
, nest 2 $ ppr_skol skol $$
vcat [ text "or" <+> ppr_skol skol
| skol <- skols ] ] ]
| otherwise = []
where
ppr_skol (PatSkol (RealDataCon dc) _) = text "the data constructor" <+> quotes (ppr dc)
ppr_skol (PatSkol (PatSynCon ps) _) = text "the pattern synonym" <+> quotes (ppr ps)
ppr_skol skol_info = ppr skol_info
usefulContext :: [Implication] -> PredType -> [SkolemInfoAnon]
-- usefulContext picks out the implications whose context
-- the programmer might plausibly augment to solve 'pred'
usefulContext implics pred
= go implics
where
pred_tvs = tyCoVarsOfType pred
go [] = []
go (ic : ics)
| implausible ic = rest
| otherwise = ic_info ic : rest
where
-- Stop when the context binds a variable free in the predicate
rest | any (`elemVarSet` pred_tvs) (ic_skols ic) = []
| otherwise = go ics
implausible ic
| null (ic_skols ic) = True
| implausible_info (ic_info ic) = True
| otherwise = False
implausible_info (SigSkol (InfSigCtxt {}) _ _) = True
implausible_info _ = False
-- Do not suggest adding constraints to an *inferred* type signature
pp_givens :: [Implication] -> [SDoc]
pp_givens givens
= case givens of
[] -> []
(g:gs) -> ppr_given (text "from the context:") g
: map (ppr_given (text "or from:")) gs
where
ppr_given herald implic@(Implic { ic_given = gs, ic_info = skol_info })
= hang (herald <+> pprEvVarTheta (mkMinimalBySCs evVarPred gs))
-- See Note [Suppress redundant givens during error reporting]
-- for why we use mkMinimalBySCs above.
2 (sep [ text "bound by" <+> ppr skol_info
, text "at" <+> ppr (getCtLocEnvLoc (ic_env implic)) ])
{- *********************************************************************
* *
CtOrigin information
* *
**********************************************************************-}
levelString :: TypeOrKind -> String
levelString TypeLevel = "type"
levelString KindLevel = "kind"
pprArising :: CtLoc -> SDoc
-- Used for the main, top-level error message
-- We've done special processing for TypeEq, KindEq, givens
pprArising ct_loc
| in_generated_code = empty -- See Note ["Arising from" messages in generated code]
| suppress_origin = empty
| otherwise = pprCtOrigin orig
where
orig = ctLocOrigin ct_loc
in_generated_code = ctLocEnvInGeneratedCode (ctLocEnv ct_loc)
suppress_origin
| isGivenOrigin orig = True
| otherwise = case orig of
TypeEqOrigin {} -> True -- We've done special processing
KindEqOrigin {} -> True -- for TypeEq, KindEq, givens
AmbiguityCheckOrigin {} -> True -- The "In the ambiguity check" context
-- is sufficient; more would be repetitive
_ -> False
-- Add the "arising from..." part to a message
addArising :: CtLoc -> SDoc -> SDoc
addArising ct_loc msg = hang msg 2 (pprArising ct_loc)
pprWithArising :: [Ct] -> SDoc
-- Print something like
-- (Eq a) arising from a use of x at y
-- (Show a) arising from a use of p at q
-- Also return a location for the error message
-- Works for Wanted/Derived only
pprWithArising []
= panic "pprWithArising"
pprWithArising (ct:cts)
| null cts
= addArising loc (pprTheta [ctPred ct])
| otherwise
= vcat (map ppr_one (ct:cts))
where
loc = ctLoc ct
ppr_one ct' = hang (parens (pprType (ctPred ct')))
2 (pprCtLoc (ctLoc ct'))
{- Note ["Arising from" messages in generated code]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Consider code generated when we desugar code before typechecking;
see Note [Rebindable syntax and XXExprGhcRn].
In this code, constraints may be generated, but we don't want to
say "arising from a call of foo" if 'foo' doesn't appear in the
users code. We leave the actual CtOrigin untouched (partly because
it is generated in many, many places), but suppress the "Arising from"
message for constraints that originate in generated code.
-}
{- *********************************************************************
* *
SkolemInfo
* *
**********************************************************************-}
tidySkolemInfo :: TidyEnv -> SkolemInfo -> SkolemInfo
tidySkolemInfo env (SkolemInfo u sk_anon) = SkolemInfo u (tidySkolemInfoAnon env sk_anon)
----------------
tidySkolemInfoAnon :: TidyEnv -> SkolemInfoAnon -> SkolemInfoAnon
tidySkolemInfoAnon env (DerivSkol ty) = DerivSkol (tidyType env ty)
tidySkolemInfoAnon env (SigSkol cx ty tv_prs) = tidySigSkol env cx ty tv_prs
tidySkolemInfoAnon env (InferSkol ids) = InferSkol (mapSnd (tidyType env) ids)
tidySkolemInfoAnon env (UnifyForAllSkol ty) = UnifyForAllSkol (tidyType env ty)
tidySkolemInfoAnon _ info = info
tidySigSkol :: TidyEnv -> UserTypeCtxt
-> TcType -> [(Name,TcTyVar)] -> SkolemInfoAnon
-- We need to take special care when tidying SigSkol
-- See Note [SigSkol SkolemInfo] in "GHC.Tc.Types.Origin"
tidySigSkol env cx ty tv_prs
= SigSkol cx (tidy_ty env ty) tv_prs'
where
tv_prs' = mapSnd (tidyTyCoVarOcc env) tv_prs
inst_env = mkNameEnv tv_prs'
tidy_ty env (ForAllTy (Bndr tv vis) ty)
= ForAllTy (Bndr tv' vis) (tidy_ty env' ty)
where
(env', tv') = tidy_tv_bndr env tv
tidy_ty env ty@(FunTy { ft_mult = w, ft_arg = arg, ft_res = res })
= -- Look under c => t and t1 -> t2
ty { ft_mult = tidy_ty env w
, ft_arg = tidyType env arg
, ft_res = tidy_ty env res }
tidy_ty env ty = tidyType env ty
tidy_tv_bndr :: TidyEnv -> TyCoVar -> (TidyEnv, TyCoVar)
tidy_tv_bndr env@(occ_env, subst) tv
| Just tv' <- lookupNameEnv inst_env (tyVarName tv)
= ((occ_env, extendVarEnv subst tv tv'), tv')
| otherwise
= tidyVarBndr env tv
pprSkols :: SolverReportErrCtxt -> [(SkolemInfoAnon, [TcTyVar])] -> SDoc
pprSkols ctxt zonked_ty_vars
=
let tidy_ty_vars = map (bimap (tidySkolemInfoAnon (cec_tidy ctxt)) id) zonked_ty_vars
in vcat (map pp_one tidy_ty_vars)
where
no_msg = text "No skolem info - we could not find the origin of the following variables" <+> ppr zonked_ty_vars
$$ text "This should not happen, please report it as a bug following the instructions at:"
$$ text "https://gitlab.haskell.org/ghc/ghc/wikis/report-a-bug"
pp_one (UnkSkol cs, tvs)
= vcat [ hang (pprQuotedList tvs)
2 (is_or_are tvs "a" "(rigid, skolem)")
, nest 2 (text "of unknown origin")
, nest 2 (text "bound at" <+> ppr (skolsSpan tvs))
, no_msg
, prettyCallStackDoc cs
]
pp_one (RuntimeUnkSkol, tvs)
= hang (pprQuotedList tvs)
2 (is_or_are tvs "an" "unknown runtime")
pp_one (skol_info, tvs)
= vcat [ hang (pprQuotedList tvs)
2 (is_or_are tvs "a" "rigid" <+> text "bound by")
, nest 2 (pprSkolInfo skol_info)
, nest 2 (text "at" <+> ppr (skolsSpan tvs)) ]
is_or_are [_] article adjective = text "is" <+> text article <+> text adjective
<+> text "type variable"
is_or_are _ _ adjective = text "are" <+> text adjective
<+> text "type variables"
skolsSpan :: [TcTyVar] -> SrcSpan
skolsSpan skol_tvs = foldr1 combineSrcSpans (map getSrcSpan skol_tvs)
{- *********************************************************************
* *
Utilities for expected/actual messages
* *
**********************************************************************-}
mk_supplementary_ea_msg :: SolverReportErrCtxt -> TypeOrKind
-> Type -> Type -> CtOrigin -> Either [ExpectedActualInfo] MismatchMsg
mk_supplementary_ea_msg ctxt level ty1 ty2 orig
| TypeEqOrigin { uo_expected = exp, uo_actual = act } <- orig
, not (ea_looks_same ty1 ty2 exp act)
= mk_ea_msg ctxt Nothing level orig
| otherwise
= Left []
ea_looks_same :: Type -> Type -> Type -> Type -> Bool
-- True if the faulting types (ty1, ty2) look the same as
-- the expected/actual types (exp, act).
-- If so, we don't want to redundantly report the latter
ea_looks_same ty1 ty2 exp act
= (act `looks_same` ty1 && exp `looks_same` ty2) ||
(exp `looks_same` ty1 && act `looks_same` ty2)
where
looks_same t1 t2 = t1 `pickyEqType` t2
|| t1 `eqType` liftedTypeKind && t2 `eqType` liftedTypeKind
-- pickyEqType is sensitive to synonyms, so only replies True
-- when the types really look the same. However,
-- (TYPE 'LiftedRep) and Type both print the same way.
mk_ea_msg :: SolverReportErrCtxt -> Maybe ErrorItem -> TypeOrKind
-> CtOrigin -> Either [ExpectedActualInfo] MismatchMsg
-- Constructs a "Couldn't match" message
-- The (Maybe ErrorItem) says whether this is the main top-level message (Just)
-- or a supplementary message (Nothing)
mk_ea_msg ctxt at_top level
(TypeEqOrigin { uo_actual = act, uo_expected = exp, uo_thing = mb_thing })
| Just thing <- mb_thing
, KindLevel <- level
= Right $ KindMismatch { kmismatch_what = thing
, kmismatch_expected = exp
, kmismatch_actual = act }
| Just item <- at_top
, let ea = EA $ if expanded_syns then Just ea_expanded else Nothing
mismatch = mkBasicMismatchMsg ea item exp act
= Right mismatch
| otherwise
= Left $
if expanded_syns
then [ea,ea_expanded]
else [ea]
where
ea = ExpectedActual { ea_expected = exp, ea_actual = act }
ea_expanded =
ExpectedActualAfterTySynExpansion
{ ea_expanded_expected = expTy1
, ea_expanded_actual = expTy2 }
expanded_syns = cec_expand_syns ctxt
&& not (expTy1 `pickyEqType` exp && expTy2 `pickyEqType` act)
(expTy1, expTy2) = expandSynonymsToMatch exp act
mk_ea_msg _ _ _ _ = Left []
{- Note [Expanding type synonyms to make types similar]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In type error messages, if -fprint-expanded-types is used, we want to expand
type synonyms to make expected and found types as similar as possible, but we
shouldn't expand types too much to make type messages even more verbose and
harder to understand. The whole point here is to make the difference in expected
and found types clearer.
`expandSynonymsToMatch` does this, it takes two types, and expands type synonyms
only as much as necessary. Given two types t1 and t2:
* If they're already same, it just returns the types.
* If they're in form `C1 t1_1 .. t1_n` and `C2 t2_1 .. t2_m` (C1 and C2 are
type constructors), it expands C1 and C2 if they're different type synonyms.
Then it recursively does the same thing on expanded types. If C1 and C2 are
same, then it applies the same procedure to arguments of C1 and arguments of
C2 to make them as similar as possible.
Most important thing here is to keep number of synonym expansions at
minimum. For example, if t1 is `T (T3, T5, Int)` and t2 is `T (T5, T3,
Bool)` where T5 = T4, T4 = T3, ..., T1 = X, it returns `T (T3, T3, Int)` and
`T (T3, T3, Bool)`.
* Otherwise types don't have same shapes and so the difference is clearly
visible. It doesn't do any expansions and show these types.
Note that we only expand top-layer type synonyms. Only when top-layer
constructors are the same we start expanding inner type synonyms.
Suppose top-layer type synonyms of t1 and t2 can expand N and M times,
respectively. If their type-synonym-expanded forms will meet at some point (i.e.
will have same shapes according to `sameShapes` function), it's possible to find
where they meet in O(N+M) top-layer type synonym expansions and O(min(N,M))
comparisons. We first collect all the top-layer expansions of t1 and t2 in two
lists, then drop the prefix of the longer list so that they have same lengths.
Then we search through both lists in parallel, and return the first pair of
types that have same shapes. Inner types of these two types with same shapes
are then expanded using the same algorithm.
In case they don't meet, we return the last pair of types in the lists, which
has top-layer type synonyms completely expanded. (in this case the inner types
are not expanded at all, as the current form already shows the type error)
-}
-- | Expand type synonyms in given types only enough to make them as similar as
-- possible. Returned types are the same in terms of used type synonyms.
--
-- To expand all synonyms, see 'Type.expandTypeSynonyms'.
--
-- See `ExpandSynsFail` tests in tests testsuite/tests/typecheck/should_fail for
-- some examples of how this should work.
expandSynonymsToMatch :: Type -> Type -> (Type, Type)
expandSynonymsToMatch ty1 ty2 = (ty1_ret, ty2_ret)
where
(ty1_ret, ty2_ret) = go ty1 ty2
-- Returns (type synonym expanded version of first type,
-- type synonym expanded version of second type)
go :: Type -> Type -> (Type, Type)
go t1 t2
| t1 `pickyEqType` t2 =
-- Types are same, nothing to do
(t1, t2)
go (TyConApp tc1 tys1) (TyConApp tc2 tys2)
| tc1 == tc2
, tys1 `equalLength` tys2 =
-- Type constructors are same. They may be synonyms, but we don't
-- expand further. The lengths of tys1 and tys2 must be equal;
-- for example, with type S a = a, we don't want
-- to zip (S Monad Int) and (S Bool).
let (tys1', tys2') =
unzip (zipWithEqual "expandSynonymsToMatch" go tys1 tys2)
in (TyConApp tc1 tys1', TyConApp tc2 tys2')
go (AppTy t1_1 t1_2) (AppTy t2_1 t2_2) =
let (t1_1', t2_1') = go t1_1 t2_1
(t1_2', t2_2') = go t1_2 t2_2
in (mkAppTy t1_1' t1_2', mkAppTy t2_1' t2_2')
go ty1@(FunTy _ w1 t1_1 t1_2) ty2@(FunTy _ w2 t2_1 t2_2) | w1 `eqType` w2 =
let (t1_1', t2_1') = go t1_1 t2_1
(t1_2', t2_2') = go t1_2 t2_2
in ( ty1 { ft_arg = t1_1', ft_res = t1_2' }
, ty2 { ft_arg = t2_1', ft_res = t2_2' })
go (ForAllTy b1 t1) (ForAllTy b2 t2) =
-- NOTE: We may have a bug here, but we just can't reproduce it easily.
-- See D1016 comments for details and our attempts at producing a test
-- case. Short version: We probably need RnEnv2 to really get this right.
let (t1', t2') = go t1 t2
in (ForAllTy b1 t1', ForAllTy b2 t2')
go (CastTy ty1 _) ty2 = go ty1 ty2
go ty1 (CastTy ty2 _) = go ty1 ty2
go t1 t2 =
-- See Note [Expanding type synonyms to make types similar] for how this
-- works
let
t1_exp_tys = t1 : tyExpansions t1
t2_exp_tys = t2 : tyExpansions t2
t1_exps = length t1_exp_tys
t2_exps = length t2_exp_tys
dif = abs (t1_exps - t2_exps)
in
followExpansions $
zipEqual "expandSynonymsToMatch.go"
(if t1_exps > t2_exps then drop dif t1_exp_tys else t1_exp_tys)
(if t2_exps > t1_exps then drop dif t2_exp_tys else t2_exp_tys)
-- Expand the top layer type synonyms repeatedly, collect expansions in a
-- list. The list does not include the original type.
--
-- Example, if you have:
--
-- type T10 = T9
-- type T9 = T8
-- ...
-- type T0 = Int
--
-- `tyExpansions T10` returns [T9, T8, T7, ..., Int]
--
-- This only expands the top layer, so if you have:
--
-- type M a = Maybe a
--
-- `tyExpansions (M T10)` returns [Maybe T10] (T10 is not expanded)
tyExpansions :: Type -> [Type]
tyExpansions = unfoldr (\t -> (\x -> (x, x)) `fmap` coreView t)
-- Drop the type pairs until types in a pair look alike (i.e. the outer
-- constructors are the same).
followExpansions :: [(Type, Type)] -> (Type, Type)
followExpansions [] = pprPanic "followExpansions" empty
followExpansions [(t1, t2)]
| sameShapes t1 t2 = go t1 t2 -- expand subtrees
| otherwise = (t1, t2) -- the difference is already visible
followExpansions ((t1, t2) : tss)
-- Traverse subtrees when the outer shapes are the same
| sameShapes t1 t2 = go t1 t2
-- Otherwise follow the expansions until they look alike
| otherwise = followExpansions tss
sameShapes :: Type -> Type -> Bool
sameShapes AppTy{} AppTy{} = True
sameShapes (TyConApp tc1 _) (TyConApp tc2 _) = tc1 == tc2
sameShapes (FunTy {}) (FunTy {}) = True
sameShapes (ForAllTy {}) (ForAllTy {}) = True
sameShapes (CastTy ty1 _) ty2 = sameShapes ty1 ty2
sameShapes ty1 (CastTy ty2 _) = sameShapes ty1 ty2
sameShapes _ _ = False
{-
************************************************************************
* *
\subsection{Contexts for renaming errors}
* *
************************************************************************
-}
inHsDocContext :: HsDocContext -> SDoc
inHsDocContext ctxt = text "In" <+> pprHsDocContext ctxt
pprHsDocContext :: HsDocContext -> SDoc
pprHsDocContext (GenericCtx doc) = doc
pprHsDocContext (TypeSigCtx doc) = text "the type signature for" <+> doc
pprHsDocContext (StandaloneKindSigCtx doc) = text "the standalone kind signature for" <+> doc
pprHsDocContext PatCtx = text "a pattern type-signature"
pprHsDocContext SpecInstSigCtx = text "a SPECIALISE instance pragma"
pprHsDocContext DefaultDeclCtx = text "a `default' declaration"
pprHsDocContext DerivDeclCtx = text "a deriving declaration"
pprHsDocContext (RuleCtx name) = text "the rewrite rule" <+> doubleQuotes (ftext name)
pprHsDocContext (TyDataCtx tycon) = text "the data type declaration for" <+> quotes (ppr tycon)
pprHsDocContext (FamPatCtx tycon) = text "a type pattern of family instance for" <+> quotes (ppr tycon)
pprHsDocContext (TySynCtx name) = text "the declaration for type synonym" <+> quotes (ppr name)
pprHsDocContext (TyFamilyCtx name) = text "the declaration for type family" <+> quotes (ppr name)
pprHsDocContext (ClassDeclCtx name) = text "the declaration for class" <+> quotes (ppr name)
pprHsDocContext ExprWithTySigCtx = text "an expression type signature"
pprHsDocContext TypBrCtx = text "a Template-Haskell quoted type"
pprHsDocContext HsTypeCtx = text "a type argument"
pprHsDocContext HsTypePatCtx = text "a type argument in a pattern"
pprHsDocContext GHCiCtx = text "GHCi input"
pprHsDocContext (SpliceTypeCtx hs_ty) = text "the spliced type" <+> quotes (ppr hs_ty)
pprHsDocContext ClassInstanceCtx = text "GHC.Tc.Gen.Splice.reifyInstances"
pprHsDocContext (ForeignDeclCtx name)
= text "the foreign declaration for" <+> quotes (ppr name)
pprHsDocContext (ConDeclCtx [name])
= text "the definition of data constructor" <+> quotes (ppr name)
pprHsDocContext (ConDeclCtx names)
= text "the definition of data constructors" <+> interpp'SP names
pprConversionFailReason :: ConversionFailReason -> SDoc
pprConversionFailReason = \case
IllegalOccName ctxt_ns occ ->
text "Illegal" <+> pprNameSpace ctxt_ns
<+> text "name:" <+> quotes (text occ)
SumAltArityExceeded alt arity ->
text "Sum alternative" <+> int alt
<+> text "exceeds its arity," <+> int arity
IllegalSumAlt alt ->
vcat [ text "Illegal sum alternative:" <+> int alt
, nest 2 $ text "Sum alternatives must start from 1" ]
IllegalSumArity arity ->
vcat [ text "Illegal sum arity:" <+> int arity
, nest 2 $ text "Sums must have an arity of at least 2" ]
MalformedType typeOrKind ty ->
text "Malformed " <> text ty_str <+> text (show ty)
where ty_str = case typeOrKind of
TypeLevel -> "type"
KindLevel -> "kind"
IllegalLastStatement do_or_lc stmt ->
vcat [ text "Illegal last statement of" <+> pprAHsDoFlavour do_or_lc <> colon
, nest 2 $ ppr stmt
, text "(It should be an expression.)" ]
KindSigsOnlyAllowedOnGADTs ->
text "Kind signatures are only allowed on GADTs"
IllegalDeclaration declDescr bad_decls ->
sep [ text "Illegal" <+> what <+> text "in" <+> descrDoc <> colon
, nest 2 bads ]
where
(what, bads) = case bad_decls of
IllegalDecls (NE.toList -> decls) ->
(text "declaration" <> plural decls, vcat $ map ppr decls)
IllegalFamDecls (NE.toList -> decls) ->
( text "family declaration" <> plural decls, vcat $ map ppr decls)
descrDoc = text $ case declDescr of
InstanceDecl -> "an instance declaration"
WhereClause -> "a where clause"
LetBinding -> "a let expression"
LetExpression -> "a let expression"
ClssDecl -> "a class declaration"
CannotMixGADTConsWith98Cons ->
text "Cannot mix GADT constructors with Haskell 98"
<+> text "constructors"
EmptyStmtListInDoBlock ->
text "Empty stmt list in do-block"
NonVarInInfixExpr ->
text "Non-variable expression is not allowed in an infix expression"
MultiWayIfWithoutAlts ->
text "Multi-way if-expression with no alternatives"
CasesExprWithoutAlts ->
text "\\cases expression with no alternatives"
ImplicitParamsWithOtherBinds ->
text "Implicit parameters mixed with other bindings"
InvalidCCallImpent from ->
text (show from) <+> text "is not a valid ccall impent"
RecGadtNoCons ->
quotes (text "RecGadtC") <+> text "must have at least one constructor name"
GadtNoCons ->
quotes (text "GadtC") <+> text "must have at least one constructor name"
InvalidTypeInstanceHeader tys ->
text "Invalid type instance header:"
<+> text (show tys)
InvalidTyFamInstLHS lhs ->
text "Invalid type family instance LHS:"
<+> text (show lhs)
InvalidImplicitParamBinding ->
text "Implicit parameter binding only allowed in let or where"
DefaultDataInstDecl adts ->
(text "Default data instance declarations"
<+> text "are not allowed:")
$$ ppr adts
FunBindLacksEquations nm ->
text "Function binding for"
<+> quotes (text (TH.pprint nm))
<+> text "has no equations"
pprTyThingUsedWrong :: WrongThingSort -> TcTyThing -> Name -> SDoc
pprTyThingUsedWrong sort thing name =
pprTcTyThingCategory thing <+> quotes (ppr name) <+>
text "used as a" <+> pprWrongThingSort sort
pprWrongThingSort :: WrongThingSort -> SDoc
pprWrongThingSort =
text . \case
WrongThingType -> "type"
WrongThingDataCon -> "data constructor"
WrongThingPatSyn -> "pattern synonym"
WrongThingConLike -> "constructor-like thing"
WrongThingClass -> "class"
WrongThingTyCon -> "type constructor"
WrongThingAxiom -> "axiom"
pprStageCheckReason :: StageCheckReason -> SDoc
pprStageCheckReason = \case
StageCheckInstance _ t ->
text "instance for" <+> quotes (ppr t)
StageCheckSplice t ->
quotes (ppr t)
pprUninferrableTyVarCtx :: UninferrableTyVarCtx -> SDoc
pprUninferrableTyVarCtx = \case
UninfTyCtx_ClassContext theta ->
sep [ text "the class context:", pprTheta theta ]
UninfTyCtx_DataContext theta ->
sep [ text "the datatype context:", pprTheta theta ]
UninfTyCtx_ProvidedContext theta ->
sep [ text "the provided context:" , pprTheta theta ]
UninfTyCtx_TyFamRhs rhs_ty ->
sep [ text "the type family equation right-hand side:" , ppr rhs_ty ]
UninfTyCtx_TySynRhs rhs_ty ->
sep [ text "the type synonym right-hand side:" , ppr rhs_ty ]
UninfTyCtx_Sig exp_kind full_hs_ty ->
hang (text "the kind" <+> ppr exp_kind) 2
(text "of the type signature:" <+> ppr full_hs_ty)
pprPatSynInvalidRhsReason :: PatSynInvalidRhsReason -> SDoc
pprPatSynInvalidRhsReason = \case
PatSynNotInvertible p ->
text "Pattern" <+> quotes (ppr p) <+> text "is not invertible"
PatSynUnboundVar var ->
quotes (ppr var) <+> text "is not bound by the LHS of the pattern synonym"
pprBadFieldAnnotationReason :: BadFieldAnnotationReason -> SDoc
pprBadFieldAnnotationReason = \case
LazyFieldsDisabled ->
text "Lazy field annotations (~) are disabled"
UnpackWithoutStrictness ->
text "UNPACK pragma lacks '!'"
BackpackUnpackAbstractType ->
text "Ignoring unusable UNPACK pragma"
pprSuperclassCycleDetail :: SuperclassCycleDetail -> SDoc
pprSuperclassCycleDetail = \case
SCD_HeadTyVar pred ->
hang (text "one of whose superclass constraints is headed by a type variable:")
2 (quotes (ppr pred))
SCD_HeadTyFam pred ->
hang (text "one of whose superclass constraints is headed by a type family:")
2 (quotes (ppr pred))
SCD_Superclass cls ->
text "one of whose superclasses is" <+> quotes (ppr cls)
pprRoleValidationFailedReason :: Role -> RoleValidationFailedReason -> SDoc
pprRoleValidationFailedReason role = \case
TyVarRoleMismatch tv role' ->
text "type variable" <+> quotes (ppr tv) <+>
text "cannot have role" <+> ppr role <+>
text "because it was assigned role" <+> ppr role'
TyVarMissingInEnv tv ->
text "type variable" <+> quotes (ppr tv) <+> text "missing in environment"
BadCoercionRole co ->
text "coercion" <+> ppr co <+> text "has bad role" <+> ppr role
pprDisabledClassExtension :: Class -> DisabledClassExtension -> SDoc
pprDisabledClassExtension cls = \case
MultiParamDisabled n ->
text howMany <+> text "parameters for class" <+> quotes (ppr cls)
where
howMany | n == 0 = "No"
| otherwise = "Too many"
FunDepsDisabled ->
text "Fundeps in class" <+> quotes (ppr cls)
ConstrainedClassMethodsDisabled sel_id pred ->
vcat [ hang (text "Constraint" <+> quotes (ppr pred)
<+> text "in the type of" <+> quotes (ppr sel_id))
2 (text "constrains only the class type variables")]
pprImportLookup :: ImportLookupReason -> SDoc
pprImportLookup = \case
ImportLookupBad k iface decl_spec ie _ps ->
let
pprImpDeclSpec :: ModIface -> ImpDeclSpec -> SDoc
pprImpDeclSpec iface decl_spec =
quotes (ppr (moduleName $ is_mod decl_spec)) <+> case mi_boot iface of
IsBoot -> text "(hi-boot interface)"
NotBoot -> empty
withContext msgs =
hang (text "In the import of" <+> pprImpDeclSpec iface decl_spec <> colon)
2 (vcat msgs)
in case k of
BadImportNotExported _ ->
vcat
[ text "Module" <+> pprImpDeclSpec iface decl_spec <+>
text "does not export" <+> quotes (ppr ie) <> dot
]
BadImportAvailVar ->
withContext
[ text "an item called"
<+> quotes val <+> text "is exported, but it is not a type."
]
where
val_occ = rdrNameOcc $ ieName ie
val = parenSymOcc val_occ (ppr val_occ)
BadImportAvailTyCon {} ->
withContext
[ text "an item called"
<+> quotes tycon <+> text "is exported, but it is a type."
]
where
tycon_occ = rdrNameOcc $ ieName ie
tycon = parenSymOcc tycon_occ (ppr tycon_occ)
BadImportNotExportedSubordinates ns ->
withContext
[ text "an item called" <+> quotes sub <+> text "is exported, but it does not export any children"
, text "(constructors, class methods or field names) called"
<+> pprWithCommas (quotes . ppr) ns <> dot
]
where
sub_occ = rdrNameOcc $ ieName ie
sub = parenSymOcc sub_occ (ppr sub_occ)
BadImportAvailDataCon dataType_occ ->
withContext
[ text "an item called" <+> quotes datacon
, text "is exported, but it is a data constructor of"
, quotes dataType <> dot
]
where
datacon_occ = rdrNameOcc $ ieName ie
datacon = parenSymOcc datacon_occ (ppr datacon_occ)
dataType = parenSymOcc dataType_occ (ppr dataType_occ)
ImportLookupQualified rdr ->
hang (text "Illegal qualified name in import item:")
2 (ppr rdr)
ImportLookupIllegal ->
text "Illegal import item"
ImportLookupAmbiguous rdr gres ->
hang (text "Ambiguous name" <+> quotes (ppr rdr) <+> text "in import item. It could refer to:")
2 (vcat (map (ppr . greOccName) gres))
pprUnusedImport :: ImportDecl GhcRn -> UnusedImportReason -> SDoc
pprUnusedImport decl = \case
UnusedImportNone ->
vcat [ pp_herald <+> quotes pp_mod <+> text "is redundant"
, nest 2 (text "except perhaps to import instances from"
<+> quotes pp_mod)
, text "To import instances alone, use:"
<+> text "import" <+> pp_mod <> parens empty ]
UnusedImportSome sort_unused ->
sep [ pp_herald <+> quotes (pprWithCommas pp_unused sort_unused)
, text "from module" <+> quotes pp_mod <+> text "is redundant"]
where
pp_mod = ppr (unLoc (ideclName decl))
pp_herald = text "The" <+> pp_qual <+> text "import of"
pp_qual
| isImportDeclQualified (ideclQualified decl) = text "qualified"
| otherwise = empty
pp_unused = \case
UnusedImportNameRegular n ->
pprNameUnqualified n
UnusedImportNameRecField par fld_occ ->
case par of
ParentIs p -> pprNameUnqualified p <> parens (ppr fld_occ)
NoParent -> ppr fld_occ
pprUnusedName :: OccName -> UnusedNameProv -> SDoc
pprUnusedName name reason =
sep [ msg <> colon
, nest 2 $ pprNonVarNameSpace (occNameSpace name)
<+> quotes (ppr name)]
where
msg = case reason of
UnusedNameTopDecl ->
defined
UnusedNameImported mod ->
text "Imported from" <+> quotes (ppr mod) <+> text "but not used"
UnusedNameTypePattern ->
defined <+> text "on the right hand side"
UnusedNameMatch ->
defined
UnusedNameLocalBind ->
defined
defined = text "Defined but not used"
-- When printing the name, take care to qualify it in the same
-- way as the provenance reported by pprNameProvenance, namely
-- the head of 'gre_imp'. Otherwise we get confusing reports like
-- Ambiguous occurrence ‘null’
-- It could refer to either ‘T15487a.null’,
-- imported from ‘Prelude’ at T15487.hs:1:8-13
-- or ...
-- See #15487
pprAmbiguousGreName :: GlobalRdrEnv -> GlobalRdrElt -> SDoc
pprAmbiguousGreName gre_env gre
| IAmRecField fld_info <- greInfo gre
= sep [ text "the field" <+> quotes (ppr occ) <+> parent_info fld_info <> comma
, pprNameProvenance gre ]
| otherwise
= sep [ quotes (pp_qual <> dot <> ppr occ) <> comma
, pprNameProvenance gre ]
where
occ = greOccName gre
parent_info fld_info =
case first_con of
PatSynName ps -> text "of pattern synonym" <+> quotes (ppr ps)
DataConName {} ->
case greParent gre of
ParentIs par
-- For a data family, only reporting the family TyCon can be
-- unhelpful (see T23301). So we give a bit of additional
-- info in that case.
| Just par_gre <- lookupGRE_Name gre_env par
, IAmTyCon tc_flav <- greInfo par_gre
, OpenFamilyFlavour IAmData _ <- tc_flav
-> vcat [ ppr_cons
, text "in a data family instance of" <+> quotes (ppr par) ]
| otherwise
-> text "of record" <+> quotes (ppr par)
NoParent -> ppr_cons
where
cons :: [ConLikeName]
cons = nonDetEltsUniqSet $ recFieldCons fld_info
first_con :: ConLikeName
first_con = head cons
ppr_cons :: SDoc
ppr_cons = hsep [ text "belonging to data constructor"
, quotes (ppr $ nameOccName $ conLikeName_Name first_con)
, if length cons > 1 then parens (text "among others") else empty
]
pp_qual
| gre_lcl gre
= ppr (nameModule $ greName gre)
| Just imp <- headMaybe $ gre_imp gre
-- This 'imp' is the one that
-- pprNameProvenance chooses
, ImpDeclSpec { is_as = mod } <- is_decl imp
= ppr mod
| otherwise
= pprPanic "addNameClassErrRn" (ppr gre)
-- Invariant: either 'lcl' is True or 'iss' is non-empty
pprNonCanonicalDefinition :: LHsSigType GhcRn
-> NonCanonicalDefinition
-> SDoc
pprNonCanonicalDefinition inst_ty = \case
NonCanonicalMonoid sub -> case sub of
NonCanonical_Sappend ->
msg1 "(<>)" "mappend"
NonCanonical_Mappend ->
msg2 "mappend" "(<>)"
NonCanonicalMonad sub -> case sub of
NonCanonical_Pure ->
msg1 "pure" "return"
NonCanonical_ThenA ->
msg1 "(*>)" "(>>)"
NonCanonical_Return ->
msg2 "return" "pure"
NonCanonical_ThenM ->
msg2 "(>>)" "(*>)"
where
msg1 :: String -> String -> SDoc
msg1 lhs rhs =
vcat [ text "Noncanonical" <+>
quotes (text (lhs ++ " = " ++ rhs)) <+>
text "definition detected"
, inst
]
msg2 :: String -> String -> SDoc
msg2 lhs rhs =
vcat [ text "Noncanonical" <+>
quotes (text lhs) <+>
text "definition detected"
, inst
, quotes (text lhs) <+>
text "will eventually be removed in favour of" <+>
quotes (text rhs)
]
inst = instDeclCtxt1 inst_ty
-- stolen from GHC.Tc.TyCl.Instance
instDeclCtxt1 :: LHsSigType GhcRn -> SDoc
instDeclCtxt1 hs_inst_ty
= inst_decl_ctxt (ppr (getLHsInstDeclHead hs_inst_ty))
inst_decl_ctxt :: SDoc -> SDoc
inst_decl_ctxt doc = hang (text "in the instance declaration for")
2 (quotes doc <> text ".")
suggestNonCanonicalDefinition :: NonCanonicalDefinition -> [GhcHint]
suggestNonCanonicalDefinition reason =
[action doc]
where
action = case reason of
NonCanonicalMonoid sub -> case sub of
NonCanonical_Sappend -> move sappendName mappendName
NonCanonical_Mappend -> remove mappendName sappendName
NonCanonicalMonad sub -> case sub of
NonCanonical_Pure -> move pureAName returnMName
NonCanonical_ThenA -> move thenAName thenMName
NonCanonical_Return -> remove returnMName pureAName
NonCanonical_ThenM -> remove thenMName thenAName
move = SuggestMoveNonCanonicalDefinition
remove = SuggestRemoveNonCanonicalDefinition
doc = case reason of
NonCanonicalMonoid _ -> doc_monoid
NonCanonicalMonad _ -> doc_monad
doc_monoid =
"https://gitlab.haskell.org/ghc/ghc/-/wikis/proposal/semigroup-monoid"
doc_monad =
"https://gitlab.haskell.org/ghc/ghc/-/wikis/proposal/monad-of-no-return"
suggestDefaultDeclaration :: Class-> [Type] -> [[Type]] -> [GhcHint]
suggestDefaultDeclaration cls prefix seqs =
[SuggestDefaultDeclaration cls $ supersequence (prefix : seqs)]
where
-- Not exactly the shortest possible supersequence, but it preserves
-- the head sequence as the prefix of the result which is a requirement.
supersequence :: [[Type]] -> [Type]
supersequence [] = []
supersequence ([] : seqs) = supersequence seqs
supersequence ((x : xs) : seqs) =
x : supersequence (xs : (dropHead x <$> seqs))
dropHead x ys@(y : ys')
| tcEqType x y = ys'
| otherwise = ys
dropHead _ [] = []
--------------------------------------------------------------------------------
-- hs-boot mismatch errors
pprBootMismatch :: HsBootOrSig -> BootMismatch -> SDoc
pprBootMismatch boot_or_sig = \case
MissingBootThing nm err ->
let def_or_exp = case err of
MissingBootDefinition -> text "defined in"
MissingBootExport -> text "exported by"
in quotes (ppr nm) <+> text "is exported by the"
<+> ppr_boot_or_sig <> comma
<+> text "but not"
<+> def_or_exp <+> text "the implementing module."
MissingBootInstance boot_dfun ->
hang (text "instance" <+> ppr (idType boot_dfun))
2 (text "is defined in the" <+> ppr ppr_boot_or_sig <> comma <+>
text "but not in the implementing module.")
BadReexportedBootThing name name' ->
withUserStyle alwaysQualify AllTheWay $ vcat
[ text "The" <+> ppr_boot_or_sig
<+> text "(re)exports" <+> quotes (ppr name)
, text "but the implementing module exports a different identifier" <+> quotes (ppr name')
]
BootMismatch boot_thing real_thing err ->
vcat
[ ppr real_thing <+>
text "has conflicting definitions in the module"
, text "and its" <+> ppr_boot_or_sig <> dot,
text "Main module:" <+> real_doc
, (case boot_or_sig of
HsBoot -> text " Boot file:"
Hsig -> text " Hsig file:") <+> boot_doc
, pprBootMismatchWhat boot_or_sig err
]
where
to_doc
= pprTyThingInContext $
showToHeader
{ ss_forall =
case boot_or_sig of
HsBoot -> ShowForAllMust
Hsig -> ShowForAllWhen }
real_doc = to_doc real_thing
boot_doc = to_doc boot_thing
where
ppr_boot_or_sig = case boot_or_sig of
HsBoot -> text "hs-boot file"
Hsig -> text "hsig file"
pprBootMismatchWhat :: HsBootOrSig -> BootMismatchWhat -> SDoc
pprBootMismatchWhat boot_or_sig = \case
BootMismatchedIdTypes {} ->
text "The two types are different."
BootMismatchedTyCons tc1 tc2 errs ->
vcat $ map (pprBootTyConMismatch boot_or_sig tc1 tc2) (NE.toList errs)
pprBootTyConMismatch :: HsBootOrSig -> TyCon -> TyCon
-> BootTyConMismatch -> SDoc
pprBootTyConMismatch boot_or_sig tc1 tc2 = \case
TyConKindMismatch ->
text "The types have different kinds."
TyConRoleMismatch sub_type ->
if sub_type
then
text "The roles are not compatible:" $$
text "Main module:" <+> ppr (tyConRoles tc1) $$
text " Hsig file:" <+> ppr (tyConRoles tc2)
else
text "The roles do not match." $$
if boot_or_sig == HsBoot
then note $ "Roles on abstract types default to" <+> quotes "representational" <+> "in hs-boot files"
else empty
TyConSynonymMismatch {} -> empty -- nothing interesting to say
TyConFlavourMismatch fam_flav1 fam_flav2 ->
whenPprDebug $
text "Family flavours" <+> ppr fam_flav1 <+> text "and" <+> ppr fam_flav2 <+>
text "do not match"
TyConAxiomMismatch ax_errs ->
pprBootListMismatches (text "Type family equations do not match:")
pprTyConAxiomMismatch ax_errs
TyConInjectivityMismatch {} ->
text "Injectivity annotations do not match"
TyConMismatchedClasses _ _ err ->
pprBootClassMismatch boot_or_sig err
TyConMismatchedData _rhs1 _rhs2 err ->
pprBootDataMismatch err
SynAbstractData err ->
pprSynAbstractDataError err
TyConsVeryDifferent ->
empty -- should be obvious to the user what the problem is
pprSynAbstractDataError :: SynAbstractDataError -> SDoc
pprSynAbstractDataError = \case
SynAbsDataTySynNotNullary ->
text "Illegal parameterized type synonym in implementation of abstract data."
SynAbstractDataInvalidRHS bad_sub_tys ->
let msgs = mapMaybe pprInvalidAbstractSubTy (NE.toList bad_sub_tys)
in case msgs of
[] -> herald <> dot
msg:[] -> hang (herald <> colon)
2 msg
_ -> hang (herald <> colon)
2 (vcat $ map (<+> bullet) msgs)
where
herald = text "Illegal implementation of abstract data"
pprInvalidAbstractSubTy = \case
TyConApp tc _
-> assertPpr (isTypeFamilyTyCon tc) (ppr tc) $
Just $ text "Invalid type family" <+> quotes (ppr tc) <> dot
ty@(ForAllTy {})
-> Just $ text "Invalid polymorphic type" <> colon <+> ppr ty <> dot
ty@(FunTy af _ _ _)
| not (af == FTF_T_T)
-> Just $ text "Invalid qualified type" <> colon <+> ppr ty <> dot
_ -> Nothing
pprTyConAxiomMismatch :: BootListMismatch CoAxBranch BootAxiomBranchMismatch -> SDoc
pprTyConAxiomMismatch = \case
MismatchedLength ->
text "The number of equations differs."
MismatchedThing i br1 br2 err ->
hang (text "The" <+> speakNth (i+1) <+> text "equations do not match.")
2 (pprCoAxBranchMismatch br1 br2 err)
pprCoAxBranchMismatch :: CoAxBranch -> CoAxBranch -> BootAxiomBranchMismatch -> SDoc
pprCoAxBranchMismatch _br1 _br2 err =
text "The" <+> what <+> text "don't match."
where
what = case err of
MismatchedAxiomBinders -> text "variables bound in the equation"
MismatchedAxiomLHS -> text "equation left-hand sides"
MismatchedAxiomRHS -> text "equation right-hand sides"
pprBootListMismatches :: SDoc -- ^ herald
-> (BootListMismatch item err -> SDoc)
-> BootListMismatches item err -> SDoc
pprBootListMismatches herald ppr_one errs =
hang herald 2 msgs
where
msgs = case errs of
err :| [] -> ppr_one err
_ -> vcat $ map ((bullet <+>) . ppr_one) $ NE.toList errs
pprBootClassMismatch :: HsBootOrSig -> BootClassMismatch -> SDoc
pprBootClassMismatch boot_or_sig = \case
MismatchedMethods errs ->
pprBootListMismatches (text "The class methods do not match:")
pprBootClassMethodListMismatch errs
MismatchedATs at_errs ->
pprBootListMismatches (text "The associated types do not match:")
(pprATMismatch boot_or_sig) at_errs
MismatchedFunDeps ->
text "The functional dependencies do not match."
MismatchedSuperclasses ->
text "The superclass constraints do not match."
MismatchedMinimalPragmas ->
text "The MINIMAL pragmas are not compatible."
pprATMismatch :: HsBootOrSig -> BootListMismatch ClassATItem BootATMismatch -> SDoc
pprATMismatch boot_or_sig = \case
MismatchedLength ->
text "The number of associated type defaults differs."
MismatchedThing i at1 at2 err ->
pprATMismatchErr boot_or_sig i at1 at2 err
pprATMismatchErr :: HsBootOrSig -> Int -> ClassATItem -> ClassATItem -> BootATMismatch -> SDoc
pprATMismatchErr boot_or_sig i (ATI tc1 _) (ATI tc2 _) = \case
MismatchedTyConAT err ->
hang (text "The associated types differ:")
2 $ pprBootTyConMismatch boot_or_sig tc1 tc2 err
MismatchedATDefaultType ->
text "The types of the" <+> speakNth (i+1) <+>
text "associated type default differ."
pprBootClassMethodListMismatch :: BootListMismatch ClassOpItem BootMethodMismatch -> SDoc
pprBootClassMethodListMismatch = \case
MismatchedLength ->
text "The number of class methods differs."
MismatchedThing _ op1 op2 err ->
pprBootClassMethodMismatch op1 op2 err
pprBootClassMethodMismatch :: ClassOpItem -> ClassOpItem -> BootMethodMismatch -> SDoc
pprBootClassMethodMismatch (op1, _) (op2, _) = \case
MismatchedMethodNames ->
text "The method names" <+> quotes pname1 <+> text "and"
<+> quotes pname2 <+> text "differ."
MismatchedMethodTypes {} ->
text "The types of" <+> pname1 <+> text "are different."
MismatchedDefaultMethods subtype_check ->
if subtype_check
then
text "The default methods associated with" <+> pname1 <+>
text "are not compatible."
else
text "The default methods associated with" <+> pname1 <+>
text "are different."
where
nm1 = idName op1
nm2 = idName op2
pname1 = quotes (ppr nm1)
pname2 = quotes (ppr nm2)
pprBootDataMismatch :: BootDataMismatch -> SDoc
pprBootDataMismatch = \case
MismatchedNewtypeVsData ->
text "Cannot match a" <+> quotes (text "data") <+>
text "definition with a" <+> quotes (text "newtype") <+>
text "definition."
MismatchedConstructors dc_errs ->
pprBootListMismatches (text "The constructors do not match:")
pprBootDataConMismatch dc_errs
MismatchedDatatypeContexts {} ->
text "The datatype contexts do not match."
pprBootDataConMismatch :: BootListMismatch DataCon BootDataConMismatch
-> SDoc
pprBootDataConMismatch = \case
MismatchedLength ->
text "The number of constructors differs."
MismatchedThing _ dc1 dc2 err ->
pprBootDataConMismatchErr dc1 dc2 err
pprBootDataConMismatchErr :: DataCon -> DataCon -> BootDataConMismatch -> SDoc
pprBootDataConMismatchErr dc1 dc2 = \case
MismatchedDataConNames ->
text "The names" <+> pname1 <+> text "and" <+> pname2 <+> text "differ."
MismatchedDataConFixities ->
text "The fixities of" <+> pname1 <+> text "differ."
MismatchedDataConBangs ->
text "The strictness annotations for" <+> pname1 <+> text "differ."
MismatchedDataConFieldLabels ->
text "The record label lists for" <+> pname1 <+> text "differ."
MismatchedDataConTypes ->
text "The types for" <+> pname1 <+> text "differ."
where
name1 = dataConName dc1
name2 = dataConName dc2
pname1 = quotes (ppr name1)
pname2 = quotes (ppr name2)
--------------------------------------------------------------------------------
-- Illegal instance errors
pprIllegalInstance :: IllegalInstanceReason -> SDoc
pprIllegalInstance = \case
IllegalClassInstance head_ty reason ->
pprIllegalClassInstanceReason head_ty reason
IllegalFamilyInstance reason ->
pprIllegalFamilyInstance reason
IllegalFamilyApplicationInInstance inst_ty invis_arg tf_tc tf_args ->
pprWithInvisibleBitsWhen invis_arg $
hang (text "Illegal type synonym family application"
<+> quotes (ppr tf_ty) <+> text "in instance" <> colon)
2 (ppr inst_ty)
where
tf_ty = mkTyConApp tf_tc tf_args
pprIllegalClassInstanceReason :: TypedThing -> IllegalClassInstanceReason -> SDoc
pprIllegalClassInstanceReason head_ty = \case
IllegalInstanceHead reason ->
pprIllegalInstanceHeadReason head_ty reason
IllegalHasFieldInstance has_field_err ->
with_illegal_instance_header head_ty $
pprIllegalHasFieldInstance has_field_err
IllegalSpecialClassInstance cls because_safeHaskell ->
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
IllegalInstanceFailsCoverageCondition cls coverage_failure ->
with_illegal_instance_header head_ty $
pprNotCovered cls coverage_failure
pprIllegalInstanceHeadReason :: TypedThing
-> IllegalInstanceHeadReason -> SDoc
pprIllegalInstanceHeadReason head_ty = \case
InstHeadTySynArgs -> with_illegal_instance_header head_ty $
text "All instance types must be of the form (T t1 ... tn)" $$
text "where T is not a synonym."
InstHeadNonTyVarArgs -> with_illegal_instance_header head_ty $ vcat [
text "All instance types must be of the form (T a1 ... an)",
text "where a1 ... an are *distinct type variables*,",
text "and each type variable appears at most once in the instance head."]
InstHeadMultiParam -> with_illegal_instance_header head_ty $ parens $
text "Only one type can be given in an instance head."
InstHeadAbstractClass clas ->
text "Cannot define instance for abstract class" <+>
quotes (ppr (className clas))
InstHeadNonClass bad_head ->
vcat [ text "Illegal" <+> what_illegal <> dot
, text "Instance heads must be of the form"
, nest 2 $ text "C ty_1 ... ty_n"
, text "where" <+> quotes (char 'C') <+> text "is a class."
]
where
what_illegal = case bad_head of
Just tc ->
text "instance for" <+> ppr (tyConFlavour tc) <+> quotes (ppr $ tyConName tc)
Nothing ->
text "head of an instance declaration:" <+> quotes (ppr head_ty)
with_illegal_instance_header :: TypedThing -> SDoc -> SDoc
with_illegal_instance_header head_ty msg =
hang (hang (text "Illegal instance declaration for")
2 (quotes (ppr head_ty)) <> colon)
2 msg
pprIllegalHasFieldInstance :: IllegalHasFieldInstance -> SDoc
pprIllegalHasFieldInstance = \case
IllegalHasFieldInstanceNotATyCon
-> text "Record data type must be specified."
IllegalHasFieldInstanceFamilyTyCon
-> text "Record data type may not be a data family."
IllegalHasFieldInstanceTyConHasField tc lbl
-> quotes (ppr tc) <+> text "already has a field" <+> quotes (ppr lbl) <> dot
IllegalHasFieldInstanceTyConHasFields tc lbl
-> sep [ ppr_tc <+> text "has fields, and the type" <+> quotes (ppr lbl)
, text "could unify with one of the field labels of" <+> ppr_tc <> dot ]
where ppr_tc = quotes (ppr tc)
pprNotCovered :: Class -> CoverageProblem -> SDoc
pprNotCovered clas
CoverageProblem
{ not_covered_fundep = fd
, not_covered_fundep_inst = (ls, rs)
, not_covered_invis_vis_tvs = undetermined_tvs
, not_covered_liberal = which_cc_failed
} =
pprWithInvisibleBitsWhen (isEmptyVarSet $ pSnd undetermined_tvs) $
vcat [ sep [ text "The"
<+> ppWhen liberal (text "liberal")
<+> text "coverage condition fails in class"
<+> quotes (ppr clas)
, nest 2 $ text "for functional dependency:"
<+> quotes (pprFunDep fd) ]
, sep [ text "Reason: lhs type" <> plural ls <+> pprQuotedList ls
, nest 2 $
(if isSingleton ls
then text "does not"
else text "do not jointly")
<+> text "determine rhs type" <> plural rs
<+> pprQuotedList rs ]
, text "Un-determined variable" <> pluralVarSet undet_set <> colon
<+> pprVarSet undet_set (pprWithCommas ppr)
]
where
liberal = case which_cc_failed of
FailedLICC -> True
FailedICC {} -> False
undet_set = fold undetermined_tvs
illegalInstanceHints :: IllegalInstanceReason -> [GhcHint]
illegalInstanceHints = \case
IllegalClassInstance _ reason ->
illegalClassInstanceHints reason
IllegalFamilyInstance reason ->
illegalFamilyInstanceHints reason
IllegalFamilyApplicationInInstance {} ->
noHints
illegalInstanceReason :: IllegalInstanceReason -> DiagnosticReason
illegalInstanceReason = \case
IllegalClassInstance _ reason ->
illegalClassInstanceReason reason
IllegalFamilyInstance reason ->
illegalFamilyInstanceReason reason
IllegalFamilyApplicationInInstance {} ->
ErrorWithoutFlag
illegalClassInstanceHints :: IllegalClassInstanceReason -> [GhcHint]
illegalClassInstanceHints = \case
IllegalInstanceHead reason ->
illegalInstanceHeadHints reason
IllegalHasFieldInstance has_field_err ->
illegalHasFieldInstanceHints has_field_err
IllegalSpecialClassInstance {} -> noHints
IllegalInstanceFailsCoverageCondition _ coverage_failure ->
failedCoverageConditionHints coverage_failure
illegalClassInstanceReason :: IllegalClassInstanceReason -> DiagnosticReason
illegalClassInstanceReason = \case
IllegalInstanceHead reason ->
illegalInstanceHeadReason reason
IllegalHasFieldInstance has_field_err ->
illegalHasFieldInstanceReason has_field_err
IllegalSpecialClassInstance {} -> ErrorWithoutFlag
IllegalInstanceFailsCoverageCondition _ coverage_failure ->
failedCoverageConditionReason coverage_failure
illegalInstanceHeadHints :: IllegalInstanceHeadReason -> [GhcHint]
illegalInstanceHeadHints = \case
InstHeadTySynArgs ->
[suggestExtension LangExt.TypeSynonymInstances]
InstHeadNonTyVarArgs ->
[suggestExtension LangExt.FlexibleInstances]
InstHeadMultiParam ->
[suggestExtension LangExt.MultiParamTypeClasses]
InstHeadAbstractClass {} ->
noHints
InstHeadNonClass {} ->
noHints
illegalInstanceHeadReason :: IllegalInstanceHeadReason -> DiagnosticReason
illegalInstanceHeadReason = \case
-- These are serious
InstHeadAbstractClass {} ->
ErrorWithoutFlag
InstHeadNonClass {} ->
ErrorWithoutFlag
-- These are less serious (enable an extension)
InstHeadTySynArgs ->
ErrorWithoutFlag
InstHeadNonTyVarArgs ->
ErrorWithoutFlag
InstHeadMultiParam ->
ErrorWithoutFlag
illegalHasFieldInstanceHints :: IllegalHasFieldInstance -> [GhcHint]
illegalHasFieldInstanceHints = \case
IllegalHasFieldInstanceNotATyCon
-> noHints
IllegalHasFieldInstanceFamilyTyCon
-> noHints
IllegalHasFieldInstanceTyConHasField {}
-> noHints
IllegalHasFieldInstanceTyConHasFields {}
-> noHints
illegalHasFieldInstanceReason :: IllegalHasFieldInstance -> DiagnosticReason
illegalHasFieldInstanceReason = \case
IllegalHasFieldInstanceNotATyCon
-> ErrorWithoutFlag
IllegalHasFieldInstanceFamilyTyCon
-> ErrorWithoutFlag
IllegalHasFieldInstanceTyConHasField {}
-> ErrorWithoutFlag
IllegalHasFieldInstanceTyConHasFields {}
-> ErrorWithoutFlag
failedCoverageConditionHints :: CoverageProblem -> [GhcHint]
failedCoverageConditionHints (CoverageProblem { not_covered_liberal = failed_cc })
= case failed_cc of
FailedLICC -> noHints
FailedICC { alsoFailedLICC = failed_licc } ->
-- Turning on UndecidableInstances makes the check liberal,
-- so if the liberal check passes, suggest enabling UndecidableInstances.
if failed_licc
then noHints
else [suggestExtension LangExt.UndecidableInstances]
failedCoverageConditionReason :: CoverageProblem -> DiagnosticReason
failedCoverageConditionReason _ = ErrorWithoutFlag
pprIllegalFamilyInstance :: IllegalFamilyInstanceReason -> SDoc
pprIllegalFamilyInstance = \case
InvalidAssoc reason -> pprInvalidAssoc reason
NotAFamilyTyCon ty_or_data tc ->
vcat [ text "Illegal family instance for" <+> quotes (ppr tc)
, nest 2 $ parens (quotes (ppr tc) <+> text "is not a" <+> what) ]
where
what = ppr ty_or_data <+> text "family"
NotAnOpenFamilyTyCon tc ->
text "Illegal instance for closed family" <+> quotes (ppr tc)
FamilyCategoryMismatch tc ->
text "Wrong category of family instance; declaration was for a" <+> what <> dot
where
what = case tyConFlavour tc of
OpenFamilyFlavour IAmData _ -> text "data family"
_ -> text "type family"
FamilyArityMismatch _ max_args ->
text "Number of parameters must match family declaration; expected"
<+> ppr max_args <> dot
TyFamNameMismatch fam_tc_name eqn_tc_name ->
hang (text "Mismatched type name in type family instance.")
2 (vcat [ text "Expected:" <+> ppr fam_tc_name
, text " Actual:" <+> ppr eqn_tc_name ])
FamInstRHSOutOfScopeTyVars mb_dodgy (NE.toList -> tvs) ->
hang (text "Out of scope type variable" <> plural tvs
<+> pprWithCommas (quotes . ppr) tvs
<+> text "in the RHS of a family instance.")
2 (text "All such variables must be bound on the LHS.")
$$ mk_extra
where
-- mk_extra: #7536: give a decent error message for
-- type T a = Int
-- type instance F (T a) = a
mk_extra = case mb_dodgy of
Nothing -> empty
Just (fam_tc, pats, dodgy_tvs) ->
ppWhen (any (`elemVarSetByKey` dodgy_tvs) (fmap nameUnique tvs)) $
hang (text "The real LHS (expanding synonyms) is:")
2 (pprTypeApp fam_tc (map expandTypeSynonyms pats))
FamInstLHSUnusedBoundTyVars (NE.toList -> bad_qtvs) ->
vcat [ not_bound_msg, not_used_msg, dodgy_msg ]
where
-- Filter to only keep user-written variables,
-- unless none were user-written in which case we report all of them
-- (as we need to report an error).
filter_user tvs
= map ifiqtv
$ case filter ifiqtv_user_written tvs of { [] -> tvs ; qvs -> qvs }
(not_bound, not_used, dodgy)
= case foldr acc_tv ([], [], []) bad_qtvs of
(nb, nu, d) -> (filter_user nb, filter_user nu, filter_user d)
acc_tv tv (nb, nu, d) = case ifiqtv_reason tv of
InvalidFamInstQTvNotUsedInRHS -> (nb, tv : nu, d)
InvalidFamInstQTvNotBoundInPats -> (tv : nb, nu, d)
InvalidFamInstQTvDodgy -> (nb, nu, tv : d)
-- Error message for type variables not bound in LHS patterns.
not_bound_msg
| null not_bound
= empty
| otherwise
= vcat [ text "The type variable" <> plural not_bound <+> pprQuotedList not_bound
<+> isOrAre not_bound <+> text "bound by a forall,"
, text "but" <+> doOrDoes not_bound <+> text "not appear in any of the LHS patterns of the family instance." ]
-- Error message for type variables bound by a forall but not used
-- in the RHS.
not_used_msg =
if null not_used
then empty
else text "The type variable" <> plural not_used <+> pprQuotedList not_used
<+> isOrAre not_used <+> text "bound by a forall," $$
text "but" <+> itOrThey not_used <+>
isOrAre not_used <> text "n't used in the family instance."
-- Error message for dodgy type variables.
-- See Note [Dodgy binding sites in type family instances] in GHC.Tc.Validity.
dodgy_msg
| null dodgy
= empty
| otherwise
= hang (text "Dodgy type variable" <> plural dodgy <+> pprQuotedList dodgy
<+> text "in the LHS of a family instance:")
2 (text "the type variable" <> plural dodgy <+> pprQuotedList dodgy
<+> text "syntactically appear" <> singular dodgy <+> text "in LHS patterns,"
$$ text "but" <+> itOrThey dodgy <+> doOrDoes dodgy <> text "n't appear in an injective position.")
illegalFamilyInstanceHints :: IllegalFamilyInstanceReason -> [GhcHint]
illegalFamilyInstanceHints = \case
InvalidAssoc rea -> invalidAssocHints rea
NotAFamilyTyCon {} -> noHints
NotAnOpenFamilyTyCon {} -> noHints
FamilyCategoryMismatch {} -> noHints
FamilyArityMismatch {} -> noHints
TyFamNameMismatch {} -> noHints
FamInstRHSOutOfScopeTyVars {} -> noHints
FamInstLHSUnusedBoundTyVars {} -> noHints
illegalFamilyInstanceReason :: IllegalFamilyInstanceReason -> DiagnosticReason
illegalFamilyInstanceReason = \case
InvalidAssoc rea -> invalidAssocReason rea
NotAFamilyTyCon {} -> ErrorWithoutFlag
NotAnOpenFamilyTyCon {} -> ErrorWithoutFlag
FamilyCategoryMismatch {} -> ErrorWithoutFlag
FamilyArityMismatch {} -> ErrorWithoutFlag
TyFamNameMismatch {} -> ErrorWithoutFlag
FamInstRHSOutOfScopeTyVars {} -> ErrorWithoutFlag
FamInstLHSUnusedBoundTyVars {} -> ErrorWithoutFlag
pprInvalidAssoc :: InvalidAssoc -> SDoc
pprInvalidAssoc = \case
InvalidAssocInstance rea -> pprInvalidAssocInstance rea
InvalidAssocDefault rea -> pprInvalidAssocDefault rea
pprInvalidAssocInstance :: InvalidAssocInstance -> SDoc
pprInvalidAssocInstance = \case
AssocInstanceMissing name ->
text "No explicit" <+> text "associated type"
<+> text "or default declaration for"
<+> quotes (ppr name)
AssocInstanceNotInAClass fam_tc ->
text "Associated type" <+> quotes (ppr fam_tc) <+>
text "must be inside a class instance"
AssocNotInThisClass cls fam_tc ->
hsep [ text "Class", quotes (ppr cls)
, text "does not have an associated type", quotes (ppr fam_tc) ]
AssocNoClassTyVar cls fam_tc ->
sep [ text "The associated type" <+> quotes (ppr fam_tc <+> hsep (map ppr (tyConTyVars fam_tc)))
, text "mentions none of the type or kind variables of the class" <+>
quotes (ppr cls <+> hsep (map ppr (classTyVars cls)))]
AssocTyVarsDontMatch vis fam_tc exp_tys act_tys ->
pprWithInvisibleBitsWhen (isInvisibleForAllTyFlag vis) $
vcat [ text "Type indexes must match class instance head"
, text "Expected:" <+> pp exp_tys
, text " Actual:" <+> pp act_tys ]
where
pp tys = pprIfaceTypeApp topPrec (toIfaceTyCon fam_tc) $
toIfaceTcArgs fam_tc tys
pprInvalidAssocDefault :: InvalidAssocDefault -> SDoc
pprInvalidAssocDefault = \case
AssocDefaultNotAssoc cls tc ->
hsep [ text "Class", quotes (ppr cls)
, text "does not have an associated type", quotes (ppr tc) ]
AssocMultipleDefaults name ->
text "More than one default declaration for" <+> quotes (ppr name)
AssocDefaultBadArgs fam_tc pat_tys bad_arg ->
let (pat_vis, main_msg) = case bad_arg of
AssocDefaultNonTyVarArg (pat_ty, pat_vis) ->
(pat_vis,
text "Illegal argument" <+> quotes (ppr pat_ty) <+> text "in:")
AssocDefaultDuplicateTyVars dups ->
let (pat_tv, pat_vis) = NE.head dups
in (pat_vis,
text "Illegal duplicate variable" <+> quotes (ppr pat_tv) <+> text "in:")
in pprWithInvisibleBitsWhen (isInvisibleForAllTyFlag pat_vis) $
hang main_msg
2 (vcat [ppr_eqn, suggestion])
where
ppr_eqn :: SDoc
ppr_eqn =
quotes (text "type" <+> ppr (mkTyConApp fam_tc pat_tys)
<+> equals <+> text "...")
suggestion :: SDoc
suggestion = text "The arguments to" <+> quotes (ppr fam_tc)
<+> text "must all be distinct type variables."
invalidAssocHints :: InvalidAssoc -> [GhcHint]
invalidAssocHints = \case
InvalidAssocInstance rea -> invalidAssocInstanceHints rea
InvalidAssocDefault rea -> invalidAssocDefaultHints rea
invalidAssocInstanceHints :: InvalidAssocInstance -> [GhcHint]
invalidAssocInstanceHints = \case
AssocInstanceMissing {} -> noHints
AssocInstanceNotInAClass {} -> noHints
AssocNotInThisClass {} -> noHints
AssocNoClassTyVar {} -> noHints
AssocTyVarsDontMatch {} -> noHints
invalidAssocDefaultHints :: InvalidAssocDefault -> [GhcHint]
invalidAssocDefaultHints = \case
AssocDefaultNotAssoc {} -> noHints
AssocMultipleDefaults {} -> noHints
AssocDefaultBadArgs _ _ bad ->
assocDefaultBadArgHints bad
assocDefaultBadArgHints :: AssocDefaultBadArgs -> [GhcHint]
assocDefaultBadArgHints = \case
AssocDefaultNonTyVarArg {} -> noHints
AssocDefaultDuplicateTyVars {} -> noHints
invalidAssocReason :: InvalidAssoc -> DiagnosticReason
invalidAssocReason = \case
InvalidAssocInstance rea -> invalidAssocInstanceReason rea
InvalidAssocDefault rea -> invalidAssocDefaultReason rea
invalidAssocInstanceReason :: InvalidAssocInstance -> DiagnosticReason
invalidAssocInstanceReason = \case
AssocInstanceMissing {} -> WarningWithFlag (Opt_WarnMissingMethods)
AssocInstanceNotInAClass {} -> ErrorWithoutFlag
AssocNotInThisClass {} -> ErrorWithoutFlag
AssocNoClassTyVar {} -> ErrorWithoutFlag
AssocTyVarsDontMatch {} -> ErrorWithoutFlag
invalidAssocDefaultReason :: InvalidAssocDefault -> DiagnosticReason
invalidAssocDefaultReason = \case
AssocDefaultNotAssoc {} -> ErrorWithoutFlag
AssocMultipleDefaults {} -> ErrorWithoutFlag
AssocDefaultBadArgs _ _ rea ->
assocDefaultBadArgReason rea
assocDefaultBadArgReason :: AssocDefaultBadArgs -> DiagnosticReason
assocDefaultBadArgReason = \case
AssocDefaultNonTyVarArg {} -> ErrorWithoutFlag
AssocDefaultDuplicateTyVars {} -> ErrorWithoutFlag
--------------------------------------------------------------------------------
-- Template Haskell quotes and splices
pprTHError :: THError -> DecoratedSDoc
pprTHError = \case
THSyntaxError err -> pprTHSyntaxError err
THNameError err -> pprTHNameError err
THReifyError err -> pprTHReifyError err
TypedTHError err -> pprTypedTHError err
THSpliceFailed rea -> pprSpliceFailReason rea
AddTopDeclsError err -> pprAddTopDeclsError err
IllegalStaticFormInSplice e ->
mkSimpleDecorated $
sep [ text "static forms cannot be used in splices:"
, nest 2 $ ppr e
]
FailedToLookupThInstName th_type reason ->
mkSimpleDecorated $
case reason of
NoMatchesFound ->
text "Couldn't find any instances of"
<+> text (TH.pprint th_type)
<+> text "to add documentation to"
CouldNotDetermineInstance ->
text "Couldn't work out what instance"
<+> text (TH.pprint th_type)
<+> text "is supposed to be"
AddInvalidCorePlugin plugin ->
mkSimpleDecorated $
hang (text "addCorePlugin: invalid plugin module" <+> quotes (text plugin) )
2 (text "Plugins in the current package can't be specified.")
AddDocToNonLocalDefn doc_loc ->
mkSimpleDecorated $
text "Can't add documentation to" <+> ppr_loc doc_loc <> comma <+>
text "as it isn't inside the current module."
where
ppr_loc (TH.DeclDoc n) = text $ TH.pprint n
ppr_loc (TH.ArgDoc n _) = text $ TH.pprint n
ppr_loc (TH.InstDoc t) = text $ TH.pprint t
ppr_loc TH.ModuleDoc = text "the module header"
ReportCustomQuasiError _ msg -> mkSimpleDecorated $ text msg
pprTHSyntaxError :: THSyntaxError -> DecoratedSDoc
pprTHSyntaxError = mkSimpleDecorated . \case
IllegalTHQuotes expr ->
text "Syntax error on" <+> ppr expr
-- The error message context will say
-- "In the Template Haskell quotation", so no need to repeat that here.
BadImplicitSplice ->
sep [ text "Parse error: module header, import declaration"
, text "or top-level declaration expected." ]
-- The compiler should not mention TemplateHaskell, as the common case
-- is that this is a simple beginner error, for example:
--
-- module M where
-- f :: Int -> Int; f x = x
-- xyzzy
-- g y = f y + 1
--
-- It's unlikely that 'xyzzy' above was intended to be a Template Haskell
-- splice; instead it's probably something mistakenly left in the code.
-- See #12146 for discussion.
IllegalTHSplice ->
text "Unexpected top-level splice."
MismatchedSpliceType splice_type inner_splice_or_bracket ->
inner <+> text "may not appear in" <+> outer <> dot
where
(inner, outer) = case inner_splice_or_bracket of
IsSplice -> case splice_type of
Typed -> (text "Typed splices" , text "untyped brackets")
Untyped -> (text "Untyped splices", text "typed brackets")
IsBracket ->
case splice_type of
Typed -> (text "Untyped brackets", text "typed splices")
Untyped -> (text "Typed brackets" , text "untyped splices")
NestedTHBrackets ->
text "Template Haskell brackets cannot be nested" <+>
text "(without intervening splices)"
pprTHNameError :: THNameError -> DecoratedSDoc
pprTHNameError = \case
NonExactName name ->
mkSimpleDecorated $
hang (text "The binder" <+> quotes (ppr name) <+> text "is not a NameU.")
2 (text "Probable cause: you used mkName instead of newName to generate a binding.")
QuotedNameWrongStage quote ->
mkSimpleDecorated $
sep [ text "Stage error: the non-top-level quoted name" <+> ppr quote
, text "must be used at the same stage at which it is bound." ]
pprTHReifyError :: THReifyError -> DecoratedSDoc
pprTHReifyError = \case
CannotReifyInstance ty
-> mkSimpleDecorated $
hang (text "reifyInstances:" <+> quotes (ppr ty))
2 (text "is not a class constraint or type family application")
CannotReifyOutOfScopeThing th_name
-> mkSimpleDecorated $
quotes (text (TH.pprint th_name)) <+>
text "is not in scope at a reify"
-- Ugh! Rather an indirect way to display the name
CannotReifyThingNotInTypeEnv name
-> mkSimpleDecorated $
quotes (ppr name) <+> text "is not in the type environment at a reify"
NoRolesAssociatedWithThing thing
-> mkSimpleDecorated $
text "No roles associated with" <+> (ppr thing)
CannotRepresentType sort ty
-> mkSimpleDecorated $
hsep [text "Can't represent" <+> sort_doc <+>
text "in Template Haskell:",
nest 2 (ppr ty)]
where
sort_doc = text $
case sort of
LinearInvisibleArgument -> "linear invisible argument"
CoercionsInTypes -> "coercions in types"
pprTypedTHError :: TypedTHError -> DecoratedSDoc
pprTypedTHError = \case
SplicePolymorphicLocalVar ident
-> mkSimpleDecorated $
text "Can't splice the polymorphic local variable" <+> quotes (ppr ident)
TypedTHWithPolyType ty
-> mkSimpleDecorated $
vcat [ text "Illegal polytype:" <+> ppr ty
, text "The type of a Typed Template Haskell expression must" <+>
text "not have any quantification." ]
pprSpliceFailReason :: SpliceFailReason -> DecoratedSDoc
pprSpliceFailReason = \case
SpliceThrewException phase _exn exn_msg expr show_code ->
mkSimpleDecorated $
vcat [ text "Exception when trying to" <+> text phaseStr <+> text "compile-time code:"
, nest 2 (text exn_msg)
, if show_code then text "Code:" <+> ppr expr else empty]
where phaseStr =
case phase of
SplicePhase_Run -> "run"
SplicePhase_CompileAndLink -> "compile and link"
RunSpliceFailure err -> pprRunSpliceFailure Nothing err
pprAddTopDeclsError :: AddTopDeclsError -> DecoratedSDoc
pprAddTopDeclsError = \case
InvalidTopDecl _decl ->
mkSimpleDecorated $
sep [ text "Only function, value, annotation, and foreign import declarations"
, text "may be added with" <+> quotes (text "addTopDecls") <> dot ]
AddTopDeclsUnexpectedDeclarationSplice {} ->
mkSimpleDecorated $
text "Declaration splices are not permitted" <+>
text "inside top-level declarations added with" <+>
quotes (text "addTopDecls") <> dot
AddTopDeclsRunSpliceFailure err ->
pprRunSpliceFailure (Just "addTopDecls") err
pprRunSpliceFailure :: Maybe String -> RunSpliceFailReason -> DecoratedSDoc
pprRunSpliceFailure mb_calling_fn (ConversionFail what reason) =
mkSimpleDecorated . add_calling_fn . addSpliceInfo $
pprConversionFailReason reason
where
add_calling_fn rest =
case mb_calling_fn of
Just calling_fn ->
hang (text "Error in a declaration passed to" <+> quotes (text calling_fn) <> colon)
2 rest
Nothing -> rest
addSpliceInfo = case what of
ConvDec d -> addSliceInfo' "declaration" d
ConvExp e -> addSliceInfo' "expression" e
ConvPat p -> addSliceInfo' "pattern" p
ConvType t -> addSliceInfo' "type" t
addSliceInfo' what item reasonErr = reasonErr $$ descr
where
-- Show the item in pretty syntax normally,
-- but with all its constructors if you say -dppr-debug
descr = hang (text "When splicing a TH" <+> text what <> colon)
2 (getPprDebug $ \case
True -> text (show item)
False -> text (TH.pprint item))
thErrorReason :: THError -> DiagnosticReason
thErrorReason = \case
THSyntaxError err -> thSyntaxErrorReason err
THNameError err -> thNameErrorReason err
THReifyError err -> thReifyErrorReason err
TypedTHError err -> typedTHErrorReason err
THSpliceFailed rea -> spliceFailedReason rea
AddTopDeclsError err -> addTopDeclsErrorReason err
IllegalStaticFormInSplice {} -> ErrorWithoutFlag
FailedToLookupThInstName {} -> ErrorWithoutFlag
AddInvalidCorePlugin {} -> ErrorWithoutFlag
AddDocToNonLocalDefn {} -> ErrorWithoutFlag
ReportCustomQuasiError is_error _ ->
if is_error
then ErrorWithoutFlag
else WarningWithoutFlag
thSyntaxErrorReason :: THSyntaxError -> DiagnosticReason
thSyntaxErrorReason = \case
IllegalTHQuotes{} -> ErrorWithoutFlag
BadImplicitSplice -> ErrorWithoutFlag
IllegalTHSplice{} -> ErrorWithoutFlag
NestedTHBrackets{} -> ErrorWithoutFlag
MismatchedSpliceType{} -> ErrorWithoutFlag
thNameErrorReason :: THNameError -> DiagnosticReason
thNameErrorReason = \case
NonExactName {} -> ErrorWithoutFlag
QuotedNameWrongStage {} -> ErrorWithoutFlag
thReifyErrorReason :: THReifyError -> DiagnosticReason
thReifyErrorReason = \case
CannotReifyInstance {} -> ErrorWithoutFlag
CannotReifyOutOfScopeThing {} -> ErrorWithoutFlag
CannotReifyThingNotInTypeEnv {} -> ErrorWithoutFlag
NoRolesAssociatedWithThing {} -> ErrorWithoutFlag
CannotRepresentType {} -> ErrorWithoutFlag
typedTHErrorReason :: TypedTHError -> DiagnosticReason
typedTHErrorReason = \case
SplicePolymorphicLocalVar {} -> ErrorWithoutFlag
TypedTHWithPolyType {} -> ErrorWithoutFlag
spliceFailedReason :: SpliceFailReason -> DiagnosticReason
spliceFailedReason = \case
SpliceThrewException {} -> ErrorWithoutFlag
RunSpliceFailure {} -> ErrorWithoutFlag
addTopDeclsErrorReason :: AddTopDeclsError -> DiagnosticReason
addTopDeclsErrorReason = \case
InvalidTopDecl {}
-> ErrorWithoutFlag
AddTopDeclsUnexpectedDeclarationSplice {}
-> ErrorWithoutFlag
AddTopDeclsRunSpliceFailure {}
-> ErrorWithoutFlag
thErrorHints :: THError -> [GhcHint]
thErrorHints = \case
THSyntaxError err -> thSyntaxErrorHints err
THNameError err -> thNameErrorHints err
THReifyError err -> thReifyErrorHints err
TypedTHError err -> typedTHErrorHints err
THSpliceFailed rea -> spliceFailedHints rea
AddTopDeclsError err -> addTopDeclsErrorHints err
IllegalStaticFormInSplice {} -> noHints
FailedToLookupThInstName {} -> noHints
AddInvalidCorePlugin {} -> noHints
AddDocToNonLocalDefn {} -> noHints
ReportCustomQuasiError {} -> noHints
thSyntaxErrorHints :: THSyntaxError -> [GhcHint]
thSyntaxErrorHints = \case
IllegalTHQuotes{}
-> [suggestExtension LangExt.TemplateHaskellQuotes]
BadImplicitSplice {}
-> noHints -- NB: don't suggest TemplateHaskell
-- see comments on BadImplicitSplice in pprTHSyntaxError
IllegalTHSplice{}
-> [suggestExtension LangExt.TemplateHaskell]
NestedTHBrackets{}
-> noHints
MismatchedSpliceType{}
-> noHints
thNameErrorHints :: THNameError -> [GhcHint]
thNameErrorHints = \case
NonExactName {} -> noHints
QuotedNameWrongStage {} -> noHints
thReifyErrorHints :: THReifyError -> [GhcHint]
thReifyErrorHints = \case
CannotReifyInstance {} -> noHints
CannotReifyOutOfScopeThing {} -> noHints
CannotReifyThingNotInTypeEnv {} -> noHints
NoRolesAssociatedWithThing {} -> noHints
CannotRepresentType {} -> noHints
typedTHErrorHints :: TypedTHError -> [GhcHint]
typedTHErrorHints = \case
SplicePolymorphicLocalVar {} -> noHints
TypedTHWithPolyType {} -> noHints
spliceFailedHints :: SpliceFailReason -> [GhcHint]
spliceFailedHints = \case
SpliceThrewException {} -> noHints
RunSpliceFailure {} -> noHints
addTopDeclsErrorHints :: AddTopDeclsError -> [GhcHint]
addTopDeclsErrorHints = \case
InvalidTopDecl {}
-> noHints
AddTopDeclsUnexpectedDeclarationSplice {}
-> noHints
AddTopDeclsRunSpliceFailure {}
-> noHints
--------------------------------------------------------------------------------
pprPatersonCondFailure ::
PatersonCondFailure -> PatersonCondFailureContext -> Type -> Type -> SDoc
pprPatersonCondFailure (PCF_TyVar tvs) InInstanceDecl lhs rhs =
hang (occMsg tvs)
2 (sep [ text "in the constraint" <+> quotes (ppr lhs)
, text "than in the instance head" <+> quotes (ppr rhs) ])
where
occMsg tvs = text "Variable" <> plural tvs <+> quotes (pprWithCommas ppr tvs)
<+> pp_occurs <+> text "more often"
pp_occurs | isSingleton tvs = text "occurs"
| otherwise = text "occur"
pprPatersonCondFailure (PCF_TyVar tvs) InTyFamEquation lhs rhs =
hang (occMsg tvs)
2 (sep [ text "in the type-family application" <+> quotes (ppr rhs)
, text "than in the LHS of the family instance" <+> quotes (ppr lhs) ])
where
occMsg tvs = text "Variable" <> plural tvs <+> quotes (pprWithCommas ppr tvs)
<+> pp_occurs <+> text "more often"
pp_occurs | isSingleton tvs = text "occurs"
| otherwise = text "occur"
pprPatersonCondFailure PCF_Size InInstanceDecl lhs rhs =
hang (text "The constraint" <+> quotes (ppr lhs))
2 (sep [ text "is no smaller than", pp_rhs ])
where pp_rhs = text "the instance head" <+> quotes (ppr rhs)
pprPatersonCondFailure PCF_Size InTyFamEquation lhs rhs =
hang (text "The type-family application" <+> quotes (ppr rhs))
2 (sep [ text "is no smaller than", pp_lhs ])
where pp_lhs = text "the LHS of the family instance" <+> quotes (ppr lhs)
pprPatersonCondFailure (PCF_TyFam tc) InInstanceDecl lhs _rhs =
hang (text "Illegal use of type family" <+> quotes (ppr tc))
2 (text "in the constraint" <+> quotes (ppr lhs))
pprPatersonCondFailure (PCF_TyFam tc) InTyFamEquation _lhs rhs =
hang (text "Illegal nested use of type family" <+> quotes (ppr tc))
2 (text "in the arguments of the type-family application" <+> quotes (ppr rhs))
--------------------------------------------------------------------------------
defaultTypesAndImport :: ClassDefaults -> SDoc
defaultTypesAndImport ClassDefaults{cd_types, cd_module = Just cdm} =
hang (parens $ pprWithCommas ppr cd_types)
2 (text "imported from" <+> ppr cdm)
defaultTypesAndImport ClassDefaults{cd_types} = parens (pprWithCommas ppr cd_types)
--------------------------------------------------------------------------------
pprZonkerMessage :: ZonkerMessage -> SDoc
pprZonkerMessage = \case
ZonkerCannotDefaultConcrete frr ->
ppr (frr_context frr) $$
text "cannot be assigned a fixed runtime representation," <+>
text "not even by defaulting."
zonkerMessageHints :: ZonkerMessage -> [GhcHint]
zonkerMessageHints = \case
ZonkerCannotDefaultConcrete {} -> [SuggestAddTypeSignatures UnnamedBinding]
zonkerMessageReason :: ZonkerMessage -> DiagnosticReason
zonkerMessageReason = \case
ZonkerCannotDefaultConcrete {} -> ErrorWithoutFlag
--------------------------------------------------------------------------------
pprTypeSyntaxName :: TypeSyntax -> SDoc
pprTypeSyntaxName TypeKeywordSyntax = "keyword" <+> quotes "type"
pprTypeSyntaxName ForallTelescopeSyntax = "forall telescope"
pprTypeSyntaxName ContextArrowSyntax = "context arrow (=>)"
pprTypeSyntaxName FunctionArrowSyntax = "function type arrow (->)"