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|
-- | 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.
module GHC.Tc.Plugin (
-- * Basic TcPluginM functionality
TcPluginM,
tcPluginIO,
tcPluginTrace,
unsafeTcPluginTcM,
-- * Finding Modules and Names
Finder.FindResult(..),
findImportedModule,
lookupOrig,
-- * Looking up Names in the typechecking environment
tcLookupGlobal,
tcLookupTyCon,
tcLookupDataCon,
tcLookupClass,
tcLookup,
tcLookupId,
-- * Getting the TcM state
getTopEnv,
getTargetPlatform,
getEnvs,
getInstEnvs,
getFamInstEnvs,
matchFam,
-- * Type variables
newUnique,
newFlexiTyVar,
isTouchableTcPluginM,
-- * Zonking
zonkTcType,
zonkCt,
-- * Creating constraints
newWanted,
newGiven,
newCoercionHole,
-- * Manipulating evidence bindings
newEvVar,
setEvBind,
) where
import GHC.Prelude
import GHC.Platform (Platform)
import qualified GHC.Tc.Utils.Monad as TcM
import qualified GHC.Tc.Solver.Monad as TcS
import qualified GHC.Tc.Utils.Env as TcM
import qualified GHC.Tc.Utils.TcMType as TcM
import qualified GHC.Tc.Instance.Family as TcM
import qualified GHC.Iface.Env as IfaceEnv
import qualified GHC.Unit.Finder as Finder
import GHC.Core.FamInstEnv ( FamInstEnv )
import GHC.Tc.Utils.Monad ( TcGblEnv, TcLclEnv, TcPluginM
, unsafeTcPluginTcM
, liftIO, traceTc )
import GHC.Tc.Types.Constraint ( Ct, CtLoc, CtEvidence(..) )
import GHC.Tc.Utils.TcMType ( TcTyVar, TcType )
import GHC.Tc.Utils.Env ( TcTyThing )
import GHC.Tc.Types.Evidence ( CoercionHole, EvTerm(..)
, EvExpr, EvBindsVar, EvBind, mkGivenEvBind )
import GHC.Types.Var ( EvVar )
import GHC.Unit.Module ( ModuleName, Module )
import GHC.Types.Name ( OccName, Name )
import GHC.Types.TyThing ( TyThing )
import GHC.Core.Reduction ( Reduction )
import GHC.Core.TyCon ( TyCon )
import GHC.Core.DataCon ( DataCon )
import GHC.Core.Class ( Class )
import GHC.Driver.Env ( HscEnv(..) )
import GHC.Utils.Outputable ( SDoc )
import GHC.Core.Type ( Kind, Type, PredType )
import GHC.Types.Id ( Id )
import GHC.Core.InstEnv ( InstEnvs )
import GHC.Types.Unique ( Unique )
import GHC.Types.PkgQual ( PkgQual )
-- | Perform some IO, typically to interact with an external tool.
tcPluginIO :: IO a -> TcPluginM a
tcPluginIO a = unsafeTcPluginTcM (liftIO a)
-- | Output useful for debugging the compiler.
tcPluginTrace :: String -> SDoc -> TcPluginM ()
tcPluginTrace a b = unsafeTcPluginTcM (traceTc a b)
findImportedModule :: ModuleName -> PkgQual -> TcPluginM Finder.FindResult
findImportedModule mod_name mb_pkg = do
hsc_env <- getTopEnv
tcPluginIO $ Finder.findImportedModule hsc_env mod_name mb_pkg
lookupOrig :: Module -> OccName -> TcPluginM Name
lookupOrig mod = unsafeTcPluginTcM . IfaceEnv.lookupOrig mod
tcLookupGlobal :: Name -> TcPluginM TyThing
tcLookupGlobal = unsafeTcPluginTcM . TcM.tcLookupGlobal
tcLookupTyCon :: Name -> TcPluginM TyCon
tcLookupTyCon = unsafeTcPluginTcM . TcM.tcLookupTyCon
tcLookupDataCon :: Name -> TcPluginM DataCon
tcLookupDataCon = unsafeTcPluginTcM . TcM.tcLookupDataCon
tcLookupClass :: Name -> TcPluginM Class
tcLookupClass = unsafeTcPluginTcM . TcM.tcLookupClass
tcLookup :: Name -> TcPluginM TcTyThing
tcLookup = unsafeTcPluginTcM . TcM.tcLookup
tcLookupId :: Name -> TcPluginM Id
tcLookupId = unsafeTcPluginTcM . TcM.tcLookupId
getTopEnv :: TcPluginM HscEnv
getTopEnv = unsafeTcPluginTcM TcM.getTopEnv
getTargetPlatform :: TcPluginM Platform
getTargetPlatform = unsafeTcPluginTcM TcM.getPlatform
getEnvs :: TcPluginM (TcGblEnv, TcLclEnv)
getEnvs = unsafeTcPluginTcM TcM.getEnvs
getInstEnvs :: TcPluginM InstEnvs
getInstEnvs = unsafeTcPluginTcM TcM.tcGetInstEnvs
getFamInstEnvs :: TcPluginM (FamInstEnv, FamInstEnv)
getFamInstEnvs = unsafeTcPluginTcM TcM.tcGetFamInstEnvs
matchFam :: TyCon -> [Type]
-> TcPluginM (Maybe Reduction)
matchFam tycon args = unsafeTcPluginTcM $ TcS.matchFamTcM tycon args
newUnique :: TcPluginM Unique
newUnique = unsafeTcPluginTcM TcM.newUnique
newFlexiTyVar :: Kind -> TcPluginM TcTyVar
newFlexiTyVar = unsafeTcPluginTcM . TcM.newFlexiTyVar
isTouchableTcPluginM :: TcTyVar -> TcPluginM Bool
isTouchableTcPluginM = unsafeTcPluginTcM . TcM.isTouchableTcM
-- Confused by zonking? See Note [What is zonking?] in GHC.Tc.Utils.TcMType.
zonkTcType :: TcType -> TcPluginM TcType
zonkTcType = unsafeTcPluginTcM . TcM.zonkTcType
zonkCt :: Ct -> TcPluginM Ct
zonkCt = unsafeTcPluginTcM . TcM.zonkCt
-- | Create a new Wanted constraint with the given 'CtLoc'.
newWanted :: CtLoc -> PredType -> TcPluginM CtEvidence
newWanted loc pty
= unsafeTcPluginTcM (TcM.newWantedWithLoc loc pty)
-- | Create a new given constraint, with the supplied evidence.
--
-- This should only be invoked within 'tcPluginSolve'.
newGiven :: EvBindsVar -> CtLoc -> PredType -> EvExpr -> TcPluginM CtEvidence
newGiven tc_evbinds loc pty evtm = do
new_ev <- newEvVar pty
setEvBind tc_evbinds $ mkGivenEvBind new_ev (EvExpr evtm)
return CtGiven { ctev_pred = pty, ctev_evar = new_ev, ctev_loc = loc }
-- | Create a fresh evidence variable.
--
-- This should only be invoked within 'tcPluginSolve'.
newEvVar :: PredType -> TcPluginM EvVar
newEvVar = unsafeTcPluginTcM . TcM.newEvVar
-- | Create a fresh coercion hole.
-- This should only be invoked within 'tcPluginSolve'.
newCoercionHole :: PredType -> TcPluginM CoercionHole
newCoercionHole = unsafeTcPluginTcM . TcM.newCoercionHole
-- | Bind an evidence variable.
--
-- This should only be invoked within 'tcPluginSolve'.
setEvBind :: EvBindsVar -> EvBind -> TcPluginM ()
setEvBind tc_evbinds ev_bind = do
unsafeTcPluginTcM $ TcM.addTcEvBind tc_evbinds ev_bind
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