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|
{-# LANGUAGE CPP #-}
-- | 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
FindResult(..),
findImportedModule,
lookupOrig,
-- * Looking up Names in the typechecking environment
tcLookupGlobal,
tcLookupTyCon,
tcLookupDataCon,
tcLookupClass,
tcLookup,
tcLookupId,
-- * Getting the TcM state
getTopEnv,
getEnvs,
getInstEnvs,
getFamInstEnvs,
matchFam,
-- * Type variables
newUnique,
newFlexiTyVar,
isTouchableTcPluginM,
-- * Zonking
zonkTcType,
zonkCt,
-- * Creating constraints
newWanted,
newDerived,
newGiven,
newCoercionHole,
-- * Manipulating evidence bindings
newEvVar,
setEvBind,
getEvBindsTcPluginM
) where
import GHC.Prelude
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.Driver.Finder as Finder
import GHC.Core.FamInstEnv ( FamInstEnv )
import GHC.Tc.Utils.Monad ( TcGblEnv, TcLclEnv, TcPluginM
, unsafeTcPluginTcM, getEvBindsTcPluginM
, liftIO, traceTc )
import GHC.Tc.Types.Constraint ( Ct, CtLoc, CtEvidence(..), ctLocOrigin )
import GHC.Tc.Utils.TcMType ( TcTyVar, TcType )
import GHC.Tc.Utils.Env ( TcTyThing )
import GHC.Tc.Types.Evidence ( TcCoercion, CoercionHole, EvTerm(..)
, EvExpr, EvBind, mkGivenEvBind )
import GHC.Types.Var ( EvVar )
import GHC.Types.Module
import GHC.Types.Name
import GHC.Core.TyCon
import GHC.Core.DataCon
import GHC.Core.Class
import GHC.Driver.Types
import GHC.Utils.Outputable
import GHC.Core.Type
import GHC.Core.Coercion ( BlockSubstFlag(..) )
import GHC.Types.Id
import GHC.Core.InstEnv
import GHC.Data.FastString
import GHC.Types.Unique
-- | 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 -> Maybe FastString -> TcPluginM 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
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 (TcCoercion, TcType))
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.
newWanted :: CtLoc -> PredType -> TcPluginM CtEvidence
newWanted loc pty
= unsafeTcPluginTcM (TcM.newWanted (ctLocOrigin loc) Nothing pty)
-- | Create a new derived constraint.
newDerived :: CtLoc -> PredType -> TcPluginM CtEvidence
newDerived loc pty = return CtDerived { ctev_pred = pty, ctev_loc = loc }
-- | Create a new given constraint, with the supplied evidence. This
-- must not be invoked from 'tcPluginInit' or 'tcPluginStop', or it
-- will panic.
newGiven :: CtLoc -> PredType -> EvExpr -> TcPluginM CtEvidence
newGiven loc pty evtm = do
new_ev <- newEvVar pty
setEvBind $ mkGivenEvBind new_ev (EvExpr evtm)
return CtGiven { ctev_pred = pty, ctev_evar = new_ev, ctev_loc = loc }
-- | Create a fresh evidence variable.
newEvVar :: PredType -> TcPluginM EvVar
newEvVar = unsafeTcPluginTcM . TcM.newEvVar
-- | Create a fresh coercion hole.
newCoercionHole :: PredType -> TcPluginM CoercionHole
newCoercionHole = unsafeTcPluginTcM . TcM.newCoercionHole YesBlockSubst
-- | Bind an evidence variable. This must not be invoked from
-- 'tcPluginInit' or 'tcPluginStop', or it will panic.
setEvBind :: EvBind -> TcPluginM ()
setEvBind ev_bind = do
tc_evbinds <- getEvBindsTcPluginM
unsafeTcPluginTcM $ TcM.addTcEvBind tc_evbinds ev_bind
|
