Safe Haskell	None
Language	GHC2021

GHC.Driver.Errors.Types

Contents

Constructors
Utility functions

Synopsis

data GhcMessage where
- GhcPsMessage :: PsMessage -> GhcMessage
- GhcTcRnMessage :: TcRnMessage -> GhcMessage
- GhcDsMessage :: DsMessage -> GhcMessage
- GhcDriverMessage :: DriverMessage -> GhcMessage
- GhcUnknownMessage :: UnknownDiagnostic (DiagnosticOpts GhcMessage) -> GhcMessage
data GhcMessageOpts = GhcMessageOpts {
}
data DriverMessage where
- DriverUnknownMessage :: UnknownDiagnostic (DiagnosticOpts DriverMessage) -> DriverMessage
- DriverPsHeaderMessage :: !PsMessage -> DriverMessage
- DriverMissingHomeModules :: UnitId -> [ModuleName] -> !BuildingCabalPackage -> DriverMessage
- DriverUnknownReexportedModules :: UnitId -> [ReexportedModule] -> DriverMessage
- DriverUnknownHiddenModules :: UnitId -> [ModuleName] -> DriverMessage
- DriverUnusedPackages :: [(UnitId, PackageName, Version, PackageArg)] -> DriverMessage
- DriverUnnecessarySourceImports :: !ModuleName -> DriverMessage
- DriverDuplicatedModuleDeclaration :: !Module -> [FilePath] -> DriverMessage
- DriverModuleNotFound :: !ModuleName -> DriverMessage
- DriverFileModuleNameMismatch :: !ModuleName -> !ModuleName -> DriverMessage
- DriverUnexpectedSignature :: !ModuleName -> !BuildingCabalPackage -> GenInstantiations UnitId -> DriverMessage
- DriverFileNotFound :: !FilePath -> DriverMessage
- DriverStaticPointersNotSupported :: DriverMessage
- DriverBackpackModuleNotFound :: !ModuleName -> DriverMessage
- DriverUserDefinedRuleIgnored :: !(RuleDecl GhcTc) -> DriverMessage
- DriverMixedSafetyImport :: !ModuleName -> DriverMessage
- DriverCannotLoadInterfaceFile :: !Module -> DriverMessage
- DriverInferredSafeModule :: !Module -> DriverMessage
- DriverMarkedTrustworthyButInferredSafe :: !Module -> DriverMessage
- DriverInferredSafeImport :: !Module -> DriverMessage
- DriverCannotImportUnsafeModule :: !Module -> DriverMessage
- DriverMissingSafeHaskellMode :: !Module -> DriverMessage
- DriverPackageNotTrusted :: !UnitState -> !UnitId -> DriverMessage
- DriverCannotImportFromUntrustedPackage :: !UnitState -> !Module -> DriverMessage
- DriverRedirectedNoMain :: !ModuleName -> DriverMessage
- DriverHomePackagesNotClosed :: ![UnitId] -> DriverMessage
- DriverInterfaceError :: !IfaceMessage -> DriverMessage
- DriverInconsistentDynFlags :: String -> DriverMessage
- DriverSafeHaskellIgnoredExtension :: !Extension -> DriverMessage
- DriverPackageTrustIgnored :: DriverMessage
- DriverUnrecognisedFlag :: String -> DriverMessage
- DriverDeprecatedFlag :: String -> String -> DriverMessage
- DriverModuleGraphCycle :: [ModuleGraphNode] -> DriverMessage
- DriverInstantiationNodeInDependencyGeneration :: InstantiatedUnit -> DriverMessage
- DriverNoConfiguredLLVMToolchain :: DriverMessage
data DriverMessageOpts = DriverMessageOpts {
- psDiagnosticOpts :: DiagnosticOpts PsMessage
- ifaceDiagnosticOpts :: DiagnosticOpts IfaceMessage
}
type DriverMessages = Messages DriverMessage
data PsMessage = PsHeaderMessage !PsHeaderMessage
type WarningMessages = Messages GhcMessage
type ErrorMessages = Messages GhcMessage
type WarnMsg = MsgEnvelope GhcMessage
ghcUnknownMessage :: (DiagnosticOpts a ~ NoDiagnosticOpts, Diagnostic a, Typeable a) => a -> GhcMessage
hoistTcRnMessage :: Monad m => m (Messages TcRnMessage, a) -> m (Messages GhcMessage, a)
hoistDsMessage :: Monad m => m (Messages DsMessage, a) -> m (Messages GhcMessage, a)
checkBuildingCabalPackage :: DynFlags -> BuildingCabalPackage

Documentation

data GhcMessage where Source #

The umbrella type that encompasses all the different messages that GHC might output during the different compilation stages. See Note [GhcMessage].

Constructors

GhcPsMessage :: PsMessage -> GhcMessage	A message from the parsing phase.
GhcTcRnMessage :: TcRnMessage -> GhcMessage	A message from typecheck/renaming phase.
GhcDsMessage :: DsMessage -> GhcMessage	A message from the desugaring (HsToCore) phase.
GhcDriverMessage :: DriverMessage -> GhcMessage	A message from the driver.
GhcUnknownMessage :: UnknownDiagnostic (DiagnosticOpts GhcMessage) -> GhcMessage	An "escape" hatch which can be used when we don't know the source of the message or if the message is not one of the typed ones. The `Diagnostic` and `Typeable` constraints ensure that if we know, at pattern-matching time, the originating type, we can attempt a cast and access the fully-structured error. This would be the case for a GHC plugin that offers a domain-specific error type but that doesn't want to place the burden on IDEs/application code to "know" it. The `Diagnostic` constraint ensures that worst case scenario we can still render this into something which can be eventually converted into a `DecoratedSDoc`.

Instances

Instances details

Diagnostic GhcMessage Source #

Instance details

Defined in GHC.Driver.Errors.Ppr

Associated Types

type DiagnosticOpts GhcMessage
Instance details Defined in GHC.Driver.Errors.Ppr type DiagnosticOpts GhcMessage = GhcMessageOpts

Methods

diagnosticMessage :: DiagnosticOpts GhcMessage -> GhcMessage -> DecoratedSDoc Source #

diagnosticReason :: GhcMessage -> DiagnosticReason Source #

diagnosticHints :: GhcMessage -> [GhcHint] Source #

diagnosticCode :: GhcMessage -> Maybe DiagnosticCode Source #

Generic GhcMessage Source #

Instance details

Defined in GHC.Driver.Errors.Types

Associated Types

type Rep GhcMessage

Instance details

Defined in GHC.Driver.Errors.Types

type Rep GhcMessage = D1 ('MetaData "GhcMessage" "GHC.Driver.Errors.Types" "ghc-9.12-7e51" 'False) ((C1 ('MetaCons "GhcPsMessage" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 PsMessage)) :+: C1 ('MetaCons "GhcTcRnMessage" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 TcRnMessage))) :+: (C1 ('MetaCons "GhcDsMessage" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 DsMessage)) :+: (C1 ('MetaCons "GhcDriverMessage" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 DriverMessage)) :+: C1 ('MetaCons "GhcUnknownMessage" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (UnknownDiagnostic (DiagnosticOpts GhcMessage)))))))

Methods

from :: GhcMessage -> Rep GhcMessage x #

to :: Rep GhcMessage x -> GhcMessage #

type DiagnosticOpts GhcMessage Source #

Instance details

Defined in GHC.Driver.Errors.Ppr

type DiagnosticOpts GhcMessage = GhcMessageOpts

type Rep GhcMessage Source #

Instance details

Defined in GHC.Driver.Errors.Types

type Rep GhcMessage = D1 ('MetaData "GhcMessage" "GHC.Driver.Errors.Types" "ghc-9.12-7e51" 'False) ((C1 ('MetaCons "GhcPsMessage" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 PsMessage)) :+: C1 ('MetaCons "GhcTcRnMessage" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 TcRnMessage))) :+: (C1 ('MetaCons "GhcDsMessage" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 DsMessage)) :+: (C1 ('MetaCons "GhcDriverMessage" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 DriverMessage)) :+: C1 ('MetaCons "GhcUnknownMessage" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (UnknownDiagnostic (DiagnosticOpts GhcMessage)))))))

data GhcMessageOpts Source #

Constructors

GhcMessageOpts
Fields psMessageOpts :: DiagnosticOpts PsMessage tcMessageOpts :: DiagnosticOpts TcRnMessage dsMessageOpts :: DiagnosticOpts DsMessage driverMessageOpts :: DiagnosticOpts DriverMessage

Instances

Instances details

HasDefaultDiagnosticOpts GhcMessageOpts Source #
Instance details Defined in GHC.Driver.Errors.Ppr Methods defaultOpts :: GhcMessageOpts Source #

data DriverMessage where Source #

A message from the driver.

Constructors

DriverUnknownMessage :: UnknownDiagnostic (DiagnosticOpts DriverMessage) -> DriverMessage	Simply wraps a generic `Diagnostic` message `a`.
DriverPsHeaderMessage :: !PsMessage -> DriverMessage	A parse error in parsing a Haskell file header during dependency analysis
DriverMissingHomeModules :: UnitId -> [ModuleName] -> !BuildingCabalPackage -> DriverMessage	DriverMissingHomeModules is a warning (controlled with -Wmissing-home-modules) that arises when running GHC in --make mode when some modules needed for compilation are not included on the command line. For example, if A imports B, `ghc --make A.hs` will cause this warning, while `ghc --make A.hs B.hs` will not. Useful for cabal to ensure GHC won't pick up modules listed neither in 'exposed-modules' nor in 'other-modules'. Test case: warningsshould_compileMissingMod
DriverUnknownReexportedModules :: UnitId -> [ReexportedModule] -> DriverMessage	DriverUnknown is a warning that arises when a user tries to reexport a module which isn't part of that unit.
DriverUnknownHiddenModules :: UnitId -> [ModuleName] -> DriverMessage	DriverUnknownHiddenModules is a warning that arises when a user tries to hide a module which isn't part of that unit.
DriverUnusedPackages :: [(UnitId, PackageName, Version, PackageArg)] -> DriverMessage	DriverUnusedPackages occurs when when package is requested on command line, but was never needed during compilation. Activated by -Wunused-packages. Test cases: warningsshould_compileUnusedPackages
DriverUnnecessarySourceImports :: !ModuleName -> DriverMessage	DriverUnnecessarySourceImports (controlled with -Wunused-imports) occurs if there are {-# SOURCE #-} imports which are not necessary. See `warnUnnecessarySourceImports` in `Make`. Test cases: warningsshould_compileT10637
DriverDuplicatedModuleDeclaration :: !Module -> [FilePath] -> DriverMessage	DriverDuplicatedModuleDeclaration occurs if a module `A` is declared in multiple files. Test cases: None.
DriverModuleNotFound :: !ModuleName -> DriverMessage	DriverModuleNotFound occurs if a module `A` can't be found. Test cases: None.
DriverFileModuleNameMismatch :: !ModuleName -> !ModuleName -> DriverMessage	DriverFileModuleNameMismatch occurs if a module `A` is defined in a file with a different name. The first field is the name written in the source code; the second argument is the name extracted from the filename. Test cases: modulemod178, driver/bug1677
DriverUnexpectedSignature :: !ModuleName -> !BuildingCabalPackage -> GenInstantiations UnitId -> DriverMessage	DriverUnexpectedSignature occurs when GHC encounters a module `A` that imports a signature file which is neither in the `signatures` section of a '.cabal' file nor in any package in the home modules. Example: - MyStr.hsig is defined, but not added to `signatures` in the '.cabal' file. signature MyStr where data Str - A.hs, which tries to import the signature. module A where import MyStr Test cases: driver/T12955
DriverFileNotFound :: !FilePath -> DriverMessage	DriverFileNotFound occurs when the input file (e.g. given on the command line) can't be found. Test cases: None.
DriverStaticPointersNotSupported :: DriverMessage	DriverStaticPointersNotSupported occurs when the `StaticPointers` extension is used in an interactive GHCi context. Test cases: ghciscriptsStaticPtr
DriverBackpackModuleNotFound :: !ModuleName -> DriverMessage	DriverBackpackModuleNotFound occurs when Backpack can't find a particular module during its dependency analysis. Test cases: -
DriverUserDefinedRuleIgnored :: !(RuleDecl GhcTc) -> DriverMessage	DriverUserDefinedRuleIgnored is a warning that occurs when user-defined rules are ignored. This typically happens when Safe Haskell. Test cases: testssafeHaskellsafeInfered/UnsafeWarn05 testssafeHaskellsafeInfered/UnsafeWarn06 testssafeHaskellsafeInfered/UnsafeWarn07 testssafeHaskellsafeInfered/UnsafeInfered11 testssafeHaskellsafeLanguage/SafeLang03
DriverMixedSafetyImport :: !ModuleName -> DriverMessage	DriverMixedSafetyImport is an error that occurs when a module is imported both as safe and unsafe. Test cases: testssafeHaskellsafeInfered/Mixed03 testssafeHaskellsafeInfered/Mixed02
DriverCannotLoadInterfaceFile :: !Module -> DriverMessage	DriverCannotLoadInterfaceFile is an error that occurs when we cannot load the interface file for a particular module. This can happen for example in the context of Safe Haskell, when we have to load a module to check if it can be safely imported. Test cases: None.
DriverInferredSafeModule :: !Module -> DriverMessage	DriverInferredSafeImport is a warning (controlled by the Opt_WarnSafe flag) that occurs when a module is inferred safe. Test cases: None.
DriverMarkedTrustworthyButInferredSafe :: !Module -> DriverMessage	DriverMarkedTrustworthyButInferredSafe is a warning (controlled by the Opt_WarnTrustworthySafe flag) that occurs when a module is marked trustworthy in SafeHaskell but it has been inferred safe. Test cases: testssafeHaskellsafeInfered/TrustworthySafe02 testssafeHaskellsafeInfered/TrustworthySafe03
DriverInferredSafeImport :: !Module -> DriverMessage	DriverInferredSafeImport is a warning (controlled by the Opt_WarnInferredSafeImports flag) that occurs when a safe-inferred module is imported from a safe module. Test cases: None.
DriverCannotImportUnsafeModule :: !Module -> DriverMessage	DriverCannotImportUnsafeModule is an error that occurs when an usafe module is being imported from a safe one. Test cases: None.
DriverMissingSafeHaskellMode :: !Module -> DriverMessage	DriverMissingSafeHaskellMode is a warning (controlled by the Opt_WarnMissingSafeHaskellMode flag) that occurs when a module is using SafeHaskell features but SafeHaskell mode is not enabled. Test cases: None.
DriverPackageNotTrusted :: !UnitState -> !UnitId -> DriverMessage	DriverPackageNotTrusted is an error that occurs when a package is required to be trusted but it isn't. Test cases: testssafeHaskellcheck/Check01 testssafeHaskellcheck/Check08 testssafeHaskellcheck/Check06 testssafeHaskellcheckpkg01ImpSafeOnly09 testssafeHaskellcheckpkg01ImpSafe03 testssafeHaskellcheckpkg01ImpSafeOnly07 testssafeHaskellcheckpkg01ImpSafeOnly08
DriverCannotImportFromUntrustedPackage :: !UnitState -> !Module -> DriverMessage	DriverCannotImportFromUntrustedPackage is an error that occurs in the context of Safe Haskell when trying to import a module coming from an untrusted package. Test cases: testssafeHaskellcheck/Check09 testssafeHaskellcheckpkg01ImpSafe01 testssafeHaskellcheckpkg01ImpSafe04 testssafeHaskellcheckpkg01ImpSafeOnly03 testssafeHaskellcheckpkg01ImpSafeOnly05 testssafeHaskellflags/SafeFlags17 testssafeHaskellflags/SafeFlags22 testssafeHaskellflags/SafeFlags23 testssafeHaskellghci/p11 testssafeHaskellghci/p12 testssafeHaskellghci/p17 testssafeHaskellghci/p3 testssafeHaskellsafeInfered/UnsafeInfered01 testssafeHaskellsafeInfered/UnsafeInfered02 testssafeHaskellsafeInfered/UnsafeInfered02 testssafeHaskellsafeInfered/UnsafeInfered03 testssafeHaskellsafeInfered/UnsafeInfered05 testssafeHaskellsafeInfered/UnsafeInfered06 testssafeHaskellsafeInfered/UnsafeInfered09 testssafeHaskellsafeInfered/UnsafeInfered10 testssafeHaskellsafeInfered/UnsafeInfered11 testssafeHaskellsafeInfered/UnsafeWarn01 testssafeHaskellsafeInfered/UnsafeWarn03 testssafeHaskellsafeInfered/UnsafeWarn04 testssafeHaskellsafeInfered/UnsafeWarn05 testssafeHaskellunsafeLibs/BadImport01 testssafeHaskellunsafeLibs/BadImport06 testssafeHaskellunsafeLibs/BadImport07 testssafeHaskellunsafeLibs/BadImport08 testssafeHaskellunsafeLibs/BadImport09 testssafeHaskellunsafeLibs/Dep05 testssafeHaskellunsafeLibs/Dep06 testssafeHaskellunsafeLibs/Dep07 testssafeHaskellunsafeLibs/Dep08 testssafeHaskellunsafeLibs/Dep09 testssafeHaskellunsafeLibs/Dep10
DriverRedirectedNoMain :: !ModuleName -> DriverMessage
DriverHomePackagesNotClosed :: ![UnitId] -> DriverMessage
DriverInterfaceError :: !IfaceMessage -> DriverMessage
DriverInconsistentDynFlags :: String -> DriverMessage
DriverSafeHaskellIgnoredExtension :: !Extension -> DriverMessage
DriverPackageTrustIgnored :: DriverMessage
DriverUnrecognisedFlag :: String -> DriverMessage
DriverDeprecatedFlag :: String -> String -> DriverMessage
DriverModuleGraphCycle :: [ModuleGraphNode] -> DriverMessage	DriverModuleGraphCycle is an error that occurs if the module graph contains cyclic imports. Test cases: testsbackpackshould_fail/bkpfail51 testsdriverT20459 testsdriverT24196/T24196 testsdriverT24275/T24275
DriverInstantiationNodeInDependencyGeneration :: InstantiatedUnit -> DriverMessage	DriverInstantiationNodeInDependencyGeneration is an error that occurs if the module graph used for dependency generation contains Backpack `InstantiationNode`s.
DriverNoConfiguredLLVMToolchain :: DriverMessage	DriverNoConfiguredLLVMToolchain is an error that occurs if there is no LLVM toolchain configured but -fllvm is passed as an option to the compiler. Test cases: None.

Instances

Instances details

Diagnostic DriverMessage Source #

Instance details

Defined in GHC.Driver.Errors.Ppr

Associated Types

type DiagnosticOpts DriverMessage
Instance details Defined in GHC.Driver.Errors.Ppr type DiagnosticOpts DriverMessage = DriverMessageOpts

Methods

diagnosticMessage :: DiagnosticOpts DriverMessage -> DriverMessage -> DecoratedSDoc Source #

diagnosticReason :: DriverMessage -> DiagnosticReason Source #

diagnosticHints :: DriverMessage -> [GhcHint] Source #

diagnosticCode :: DriverMessage -> Maybe DiagnosticCode Source #

Generic DriverMessage Source #

Instance details

Defined in GHC.Driver.Errors.Types

Associated Types

type Rep DriverMessage

Instance details

Defined in GHC.Driver.Errors.Types

Methods

from :: DriverMessage -> Rep DriverMessage x #

to :: Rep DriverMessage x -> DriverMessage #

type DiagnosticOpts DriverMessage Source #

Instance details

Defined in GHC.Driver.Errors.Ppr

type DiagnosticOpts DriverMessage = DriverMessageOpts

type Rep DriverMessage Source #

Instance details

Defined in GHC.Driver.Errors.Types

data DriverMessageOpts Source #

Constructors

DriverMessageOpts
Fields psDiagnosticOpts :: DiagnosticOpts PsMessage ifaceDiagnosticOpts :: DiagnosticOpts IfaceMessage

Instances

Instances details

HasDefaultDiagnosticOpts DriverMessageOpts Source #
Instance details Defined in GHC.Driver.Errors.Ppr Methods defaultOpts :: DriverMessageOpts Source #

type DriverMessages = Messages DriverMessage Source #

A collection of driver messages

data PsMessage Source #

Constructors

PsHeaderMessage !PsHeaderMessage

A group of parser messages emitted in Header. See Note [Messages from GHC.Parser.Header].

Instances

Instances details

Diagnostic PsMessage Source #

Instance details

Defined in GHC.Parser.Errors.Ppr

Associated Types

type DiagnosticOpts PsMessage
Instance details Defined in GHC.Parser.Errors.Ppr type DiagnosticOpts PsMessage = NoDiagnosticOpts

Methods

diagnosticMessage :: DiagnosticOpts PsMessage -> PsMessage -> DecoratedSDoc Source #

diagnosticReason :: PsMessage -> DiagnosticReason Source #

diagnosticHints :: PsMessage -> [GhcHint] Source #

diagnosticCode :: PsMessage -> Maybe DiagnosticCode Source #

Generic PsMessage Source #

Instance details

Defined in GHC.Parser.Errors.Types

Associated Types

type Rep PsMessage

Instance details

Defined in GHC.Parser.Errors.Types

Methods

from :: PsMessage -> Rep PsMessage x #

to :: Rep PsMessage x -> PsMessage #

type DiagnosticOpts PsMessage Source #

Instance details

Defined in GHC.Parser.Errors.Ppr

type DiagnosticOpts PsMessage = NoDiagnosticOpts

type Rep PsMessage Source #

Instance details

Defined in GHC.Parser.Errors.Types

type WarningMessages = Messages GhcMessage Source #

A collection of warning messages. INVARIANT: Each GhcMessage in the collection should have SevWarning severity.

type ErrorMessages = Messages GhcMessage Source #

A collection of error messages. INVARIANT: Each GhcMessage in the collection should have SevError severity.

type WarnMsg = MsgEnvelope GhcMessage Source #

A single warning message. INVARIANT: It must have SevWarning severity.

Constructors

ghcUnknownMessage :: (DiagnosticOpts a ~ NoDiagnosticOpts, Diagnostic a, Typeable a) => a -> GhcMessage Source #

Creates a new GhcMessage out of any diagnostic. This function is also provided to ease the integration of #18516 by allowing diagnostics to be wrapped into the general (but structured) GhcMessage type, so that the conversion can happen gradually. This function should not be needed within GHC, as it would typically be used by plugin or library authors (see comment for the GhcUnknownMessage type constructor)

Utility functions

hoistTcRnMessage :: Monad m => m (Messages TcRnMessage, a) -> m (Messages GhcMessage, a) Source #

Abstracts away the frequent pattern where we are calling ioMsgMaybe on the result of 'IO (Messages TcRnMessage, a)'.

hoistDsMessage :: Monad m => m (Messages DsMessage, a) -> m (Messages GhcMessage, a) Source #

Abstracts away the frequent pattern where we are calling ioMsgMaybe on the result of 'IO (Messages DsMessage, a)'.

checkBuildingCabalPackage :: DynFlags -> BuildingCabalPackage Source #

Checks if we are building a cabal package by consulting the DynFlags.