TcPluginM

This module provides an interface for typechecker plugins to access select functions of the TcM, principally those to do with reading parts of the state.

Basic TcPluginM functionality

data TcPluginM a

Instances

Monad TcPluginM

Defined in TcRnTypes

Methods

(>>=) :: TcPluginM a -> (a -> TcPluginM b) -> TcPluginM b

(>>) :: TcPluginM a -> TcPluginM b -> TcPluginM b

return :: a -> TcPluginM a

fail :: String -> TcPluginM a

Functor TcPluginM

Defined in TcRnTypes

Methods

fmap :: (a -> b) -> TcPluginM a -> TcPluginM b

(<$) :: a -> TcPluginM b -> TcPluginM a

MonadFail TcPluginM

Defined in TcRnTypes

Methods

fail :: String -> TcPluginM a

Applicative TcPluginM

Defined in TcRnTypes

Methods

pure :: a -> TcPluginM a

(<*>) :: TcPluginM (a -> b) -> TcPluginM a -> TcPluginM b

liftA2 :: (a -> b -> c) -> TcPluginM a -> TcPluginM b -> TcPluginM c

(*>) :: TcPluginM a -> TcPluginM b -> TcPluginM b

(<*) :: TcPluginM a -> TcPluginM b -> TcPluginM a

tcPluginIO :: IO a -> TcPluginM a

Perform some IO, typically to interact with an external tool.

tcPluginTrace :: String -> SDoc -> TcPluginM ()

Output useful for debugging the compiler.

unsafeTcPluginTcM :: TcM a -> TcPluginM a

This function provides an escape for direct access to the TcM monad. It should not be used lightly, and the provided TcPluginM API should be favoured instead.

Finding Modules and Names

data FindResult

The result of searching for an imported module.

NB: FindResult manages both user source-import lookups (which can result in Module) as well as direct imports for interfaces (which always result in InstalledModule).

Constructors

Found ModLocation Module

The module was found

NoPackage UnitId

The requested package was not found

FoundMultiple [(Module, ModuleOrigin)]

_Error_: both in multiple packages

NotFound

Not found

Fields

• fr_paths :: [FilePath]
• fr_pkg :: Maybe UnitId
• fr_mods_hidden :: [UnitId]
• fr_pkgs_hidden :: [UnitId]
• fr_unusables :: [(UnitId, UnusablePackageReason)]
• fr_suggestions :: [ModuleSuggestion]

findImportedModule :: ModuleName -> Maybe FastString -> TcPluginM FindResult

lookupOrig :: Module -> OccName -> TcPluginM Name

Looking up Names in the typechecking environment

tcLookupGlobal :: Name -> TcPluginM TyThing

tcLookupTyCon :: Name -> TcPluginM TyCon

tcLookupDataCon :: Name -> TcPluginM DataCon

tcLookupClass :: Name -> TcPluginM Class

tcLookup :: Name -> TcPluginM TcTyThing

tcLookupId :: Name -> TcPluginM Id

Getting the TcM state

getTopEnv :: TcPluginM HscEnv

getEnvs :: TcPluginM (TcGblEnv, TcLclEnv)

getInstEnvs :: TcPluginM InstEnvs

getFamInstEnvs :: TcPluginM (FamInstEnv, FamInstEnv)

matchFam :: TyCon -> [Type] -> TcPluginM (Maybe (TcCoercion, TcType))

Type variables

newUnique :: TcPluginM Unique

newFlexiTyVar :: Kind -> TcPluginM TcTyVar

isTouchableTcPluginM :: TcTyVar -> TcPluginM Bool

Zonking

zonkTcType :: TcType -> TcPluginM TcType

zonkCt :: Ct -> TcPluginM Ct

Creating constraints

newWanted :: CtLoc -> PredType -> TcPluginM CtEvidence

Create a new wanted constraint.

newDerived :: CtLoc -> PredType -> TcPluginM CtEvidence

Create a new derived constraint.

newGiven :: CtLoc -> PredType -> EvExpr -> TcPluginM CtEvidence

Create a new given constraint, with the supplied evidence. This must not be invoked from tcPluginInit or tcPluginStop, or it will panic.

newCoercionHole :: PredType -> TcPluginM CoercionHole

Create a fresh coercion hole.

Manipulating evidence bindings

newEvVar :: PredType -> TcPluginM EvVar

Create a fresh evidence variable.

setEvBind :: EvBind -> TcPluginM ()

Bind an evidence variable. This must not be invoked from tcPluginInit or tcPluginStop, or it will panic.

getEvBindsTcPluginM :: TcPluginM EvBindsVar

Access the EvBindsVar carried by the TcPluginM during constraint solving. Returns Nothing if invoked during tcPluginInit or tcPluginStop.