-- unsafeDeepSeq,
- Closure(..), getClosureData, ClosureType(..), isConstr, isIndirection,
-
- sigmaType
+ Closure(..), getClosureData, ClosureType(..), isConstr, isIndirection
) where
#include "HsVersions.h"
import DataCon
import Type
+import qualified Unify as U
import TypeRep -- I know I know, this is cheating
import Var
import TcRnMonad
import GHC.Arr ( Array(..) )
import GHC.Exts
-
-#if __GLASGOW_HASKELL__ >= 611
import GHC.IO ( IO(..) )
-#else
-import GHC.IOBase ( IO(..) )
-#endif
import Control.Monad
import Data.Maybe
newVar :: Kind -> TR TcType
newVar = liftTcM . newFlexiTyVarTy
--- | Returns the instantiated type scheme ty', and the substitution sigma
--- such that sigma(ty') = ty
-instScheme :: Type -> TR (TcType, TvSubst)
-instScheme ty = liftTcM$ do
- (tvs, _, _) <- tcInstType return ty
- (tvs',_,ty') <- tcInstType (mapM tcInstTyVar) ty
- return (ty', zipTopTvSubst tvs' (mkTyVarTys tvs))
+type RttiInstantiation = [(TcTyVar, TyVar)]
+ -- Associates the typechecker-world meta type variables
+ -- (which are mutable and may be refined), to their
+ -- debugger-world RuntimeUnk counterparts.
+ -- If the TcTyVar has not been refined by the runtime type
+ -- elaboration, then we want to turn it back into the
+ -- original RuntimeUnk
+
+-- | Returns the instantiated type scheme ty', and the
+-- mapping from new (instantiated) -to- old (skolem) type variables
+instScheme :: QuantifiedType -> TR (TcType, RttiInstantiation)
+instScheme (tvs, ty)
+ = liftTcM $ do { (tvs', _, subst) <- tcInstTyVars tvs
+ ; let rtti_inst = [(tv',tv) | (tv',tv) <- tvs' `zip` tvs]
+ ; return (substTy subst ty, rtti_inst) }
+
+applyRevSubst :: RttiInstantiation -> TR ()
+-- Apply the *reverse* substitution in-place to any un-filled-in
+-- meta tyvars. This recovers the original debugger-world variable
+-- unless it has been refined by new information from the heap
+applyRevSubst pairs = liftTcM (mapM_ do_pair pairs)
+ where
+ do_pair (tc_tv, rtti_tv)
+ = do { tc_ty <- zonkTcTyVar tc_tv
+ ; case tcGetTyVar_maybe tc_ty of
+ Just tv | isMetaTyVar tv -> writeMetaTyVar tv (mkTyVarTy rtti_tv)
+ _ -> return () }
-- Adds a constraint of the form t1 == t2
-- t1 is expected to come from walking the heap
addConstraint actual expected = do
traceTR (text "add constraint:" <+> fsep [ppr actual, equals, ppr expected])
recoverTR (traceTR $ fsep [text "Failed to unify", ppr actual,
- text "with", ppr expected])
- (congruenceNewtypes actual expected >>=
- (getConstraints . uncurry unifyType) >> return ())
+ text "with", ppr expected]) $
+ do { (ty1, ty2) <- congruenceNewtypes actual expected
+ ; _ <- captureConstraints $ unifyType ty1 ty2
+ ; return () }
-- TOMDO: what about the coercion?
-- we should consider family instances
-- we quantify existential tyvars as universal,
-- as this is needed to be able to manipulate
-- them properly
- let sigma_old_ty = sigmaType old_ty
+ let quant_old_ty@(old_tvs, old_tau) = quantifyType old_ty
+ sigma_old_ty = mkForAllTys old_tvs old_tau
traceTR (text "Term reconstruction started with initial type " <> ppr old_ty)
term <-
- if isMonomorphic sigma_old_ty
+ if null old_tvs
then do
- new_ty <- go max_depth sigma_old_ty sigma_old_ty hval >>= zonkTerm
- return $ fixFunDictionaries $ expandNewtypes new_ty
+ term <- go max_depth sigma_old_ty sigma_old_ty hval
+ term' <- zonkTerm term
+ return $ fixFunDictionaries $ expandNewtypes term'
else do
- (old_ty', rev_subst) <- instScheme sigma_old_ty
+ (old_ty', rev_subst) <- instScheme quant_old_ty
my_ty <- newVar argTypeKind
- when (check1 sigma_old_ty) (traceTR (text "check1 passed") >>
+ when (check1 quant_old_ty) (traceTR (text "check1 passed") >>
addConstraint my_ty old_ty')
term <- go max_depth my_ty sigma_old_ty hval
- zterm <- zonkTerm term
- let new_ty = termType zterm
- if isMonomorphic new_ty || check2 (sigmaType new_ty) sigma_old_ty
+ new_ty <- zonkTcType (termType term)
+ if isMonomorphic new_ty || check2 (quantifyType new_ty) quant_old_ty
then do
traceTR (text "check2 passed")
- addConstraint (termType term) old_ty'
+ addConstraint new_ty old_ty'
+ applyRevSubst rev_subst
zterm' <- zonkTerm term
- return ((fixFunDictionaries . expandNewtypes . mapTermType (substTy rev_subst)) zterm')
+ return ((fixFunDictionaries . expandNewtypes) zterm')
else do
traceTR (text "check2 failed" <+> parens
- (ppr zterm <+> text "::" <+> ppr new_ty))
+ (ppr term <+> text "::" <+> ppr new_ty))
-- we have unsound types. Replace constructor types in
-- subterms with tyvars
zterm' <- mapTermTypeM
Just (tc, _:_) | tc /= funTyCon
-> newVar argTypeKind
_ -> return ty)
- zterm
+ term
zonkTerm zterm'
traceTR (text "Term reconstruction completed." $$
text "Term obtained: " <> ppr term $$
contents_tv <- newVar liftedTypeKind
contents <- trIO$ IO$ \w -> readMutVar# (unsafeCoerce# a) w
ASSERT(isUnliftedTypeKind $ typeKind my_ty) return ()
- (mutvar_ty,_) <- instScheme $ sigmaType $ mkFunTy
+ (mutvar_ty,_) <- instScheme $ quantifyType $ mkFunTy
contents_ty (mkTyConApp tycon [world,contents_ty])
addConstraint (mkFunTy contents_tv my_ty) mutvar_ty
x <- go (pred max_depth) contents_tv contents_ty contents
cvReconstructType :: HscEnv -> Int -> GhciType -> HValue -> IO (Maybe Type)
cvReconstructType hsc_env max_depth old_ty hval = runTR_maybe hsc_env $ do
traceTR (text "RTTI started with initial type " <> ppr old_ty)
- let sigma_old_ty = sigmaType old_ty
+ let sigma_old_ty@(old_tvs, _) = quantifyType old_ty
new_ty <-
- if isMonomorphic sigma_old_ty
+ if null old_tvs
then return old_ty
else do
(old_ty', rev_subst) <- instScheme sigma_old_ty
(Seq.singleton (my_ty, hval))
max_depth
new_ty <- zonkTcType my_ty
- if isMonomorphic new_ty || check2 (sigmaType new_ty) sigma_old_ty
+ if isMonomorphic new_ty || check2 (quantifyType new_ty) sigma_old_ty
then do
- traceTR (text "check2 passed")
+ traceTR (text "check2 passed" <+> ppr old_ty $$ ppr new_ty)
addConstraint my_ty old_ty'
- new_ty' <- zonkTcType my_ty
- return (substTy rev_subst new_ty')
+ applyRevSubst rev_subst
+ zonkRttiType new_ty
else traceTR (text "check2 failed" <+> parens (ppr new_ty)) >>
return old_ty
traceTR (text "RTTI completed. Type obtained:" <+> ppr new_ty)
-- It is vital for newtype reconstruction that the unification step
-- is done right here, _before_ the subterms are RTTI reconstructed
let myType = mkFunTys subTtypes my_ty
- (signatureType,_) <- instScheme(mydataConType dc)
+ (signatureType,_) <- instScheme (mydataConType dc)
addConstraint myType signatureType
return $ [ appArr (\e->(t,e)) (ptrs clos) i
| (i,t) <- zip [0..] (filter (isLifted |.| isRefType) subTtypes)]
-- improveType <base_type> <rtti_type>
-- The types can contain skolem type variables, which need to be treated as normal vars.
-- In particular, we want them to unify with things.
-improveRTTIType :: HscEnv -> RttiType -> RttiType -> IO (Maybe TvSubst)
-improveRTTIType hsc_env _ty rtti_ty = runTR_maybe hsc_env $ do
- traceTR (text "improveRttiType" <+> fsep [ppr _ty, ppr rtti_ty])
- (ty_tvs, _, _) <- tcInstType return ty
- (ty_tvs', _, ty') <- tcInstType (mapM tcInstTyVar) ty
- (_, _, rtti_ty') <- tcInstType (mapM tcInstTyVar) (sigmaType rtti_ty)
- _ <- getConstraints(unifyType rtti_ty' ty')
- tvs1_contents <- zonkTcTyVars ty_tvs'
- let subst = (uncurry zipTopTvSubst . unzip)
- [(tv,ty) | (tv,ty) <- zip ty_tvs tvs1_contents
- , getTyVar_maybe ty /= Just tv
- --, not(isTyVarTy ty)
- ]
- return subst
- where ty = sigmaType _ty
+improveRTTIType :: HscEnv -> RttiType -> RttiType -> Maybe TvSubst
+improveRTTIType _ base_ty new_ty
+ = U.tcUnifyTys (const U.BindMe) [base_ty] [new_ty]
myDataConInstArgTys :: DataCon -> [Type] -> [Type]
myDataConInstArgTys dc args
| null (dataConExTyVars dc) && null (dataConEqTheta dc) = dataConInstArgTys dc args
| otherwise = dataConRepArgTys dc
-mydataConType :: DataCon -> Type
+mydataConType :: DataCon -> QuantifiedType
-- ^ Custom version of DataCon.dataConUserType where we
-- - remove the equality constraints
-- - use the representation types for arguments, including dictionaries
-- - keep the original result type
mydataConType dc
- = mkForAllTys ((univ_tvs `minusList` map fst eq_spec) ++ ex_tvs) $
- mkFunTys arg_tys $
- res_ty
+ = ( (univ_tvs `minusList` map fst eq_spec) ++ ex_tvs
+ , mkFunTys arg_tys res_ty )
where univ_tvs = dataConUnivTyVars dc
ex_tvs = dataConExTyVars dc
eq_spec = dataConEqSpec dc
-}
-check1 :: Type -> Bool
-check1 ty | (tvs, _, _) <- tcSplitSigmaTy ty = not $ any isHigherKind (map tyVarKind tvs)
+check1 :: QuantifiedType -> Bool
+check1 (tvs, _) = not $ any isHigherKind (map tyVarKind tvs)
where
isHigherKind = not . null . fst . splitKindFunTys
-check2 :: Type -> Type -> Bool
-check2 sigma_rtti_ty sigma_old_ty
+check2 :: QuantifiedType -> QuantifiedType -> Bool
+check2 (_, rtti_ty) (_, old_ty)
| Just (_, rttis) <- tcSplitTyConApp_maybe rtti_ty
= case () of
_ | Just (_,olds) <- tcSplitTyConApp_maybe old_ty
- -> and$ zipWith check2 rttis olds
+ -> and$ zipWith check2 (map quantifyType rttis) (map quantifyType olds)
_ | Just _ <- splitAppTy_maybe old_ty
-> isMonomorphicOnNonPhantomArgs rtti_ty
_ -> True
| otherwise = True
- where (_, _ , rtti_ty) = tcSplitSigmaTy sigma_rtti_ty
- (_, _ , old_ty) = tcSplitSigmaTy sigma_old_ty
-
-- Dealing with newtypes
--------------------------
go l r
-- TyVar lhs inductive case
| Just tv <- getTyVar_maybe l
+ , isTcTyVar tv
+ , isMetaTyVar tv
= recoverTR (return r) $ do
Indirect ty_v <- readMetaTyVar tv
traceTR $ fsep [text "(congruence) Following indirect tyvar:",
zonkTerm :: Term -> TcM Term
-zonkTerm = foldTermM TermFoldM{
- fTermM = \ty dc v tt -> zonkTcType ty >>= \ty' ->
- return (Term ty' dc v tt)
- ,fSuspensionM = \ct ty v b -> zonkTcType ty >>= \ty ->
- return (Suspension ct ty v b)
- ,fNewtypeWrapM= \ty dc t -> zonkTcType ty >>= \ty' ->
- return$ NewtypeWrap ty' dc t
- ,fRefWrapM = \ty t ->
- return RefWrap `ap` zonkTcType ty `ap` return t
- ,fPrimM = (return.) . Prim
- }
+zonkTerm = foldTermM (TermFoldM
+ { fTermM = \ty dc v tt -> zonkRttiType ty >>= \ty' ->
+ return (Term ty' dc v tt)
+ , fSuspensionM = \ct ty v b -> zonkRttiType ty >>= \ty ->
+ return (Suspension ct ty v b)
+ , fNewtypeWrapM = \ty dc t -> zonkRttiType ty >>= \ty' ->
+ return$ NewtypeWrap ty' dc t
+ , fRefWrapM = \ty t -> return RefWrap `ap`
+ zonkRttiType ty `ap` return t
+ , fPrimM = (return.) . Prim })
+
+zonkRttiType :: TcType -> TcM Type
+-- Zonk the type, replacing any unbound Meta tyvars
+-- by skolems, safely out of Meta-tyvar-land
+zonkRttiType = zonkType (mkZonkTcTyVar zonk_unbound_meta)
+ where
+ zonk_unbound_meta tv
+ = ASSERT( isTcTyVar tv )
+ do { tv' <- skolemiseUnboundMetaTyVar tv RuntimeUnk
+ -- This is where RuntimeUnks are born:
+ -- otherwise-unconstrained unification variables are
+ -- turned into RuntimeUnks as they leave the
+ -- typechecker's monad
+ ; return (mkTyVarTy tv') }
--------------------------------------------------------------------------------
-- Restore Class predicates out of a representation type
-- Use only for RTTI types
isMonomorphic :: RttiType -> Bool
isMonomorphic ty = noExistentials && noUniversals
- where (tvs, _, ty') = tcSplitSigmaTy ty
+ where (tvs, _, ty') = tcSplitSigmaTy ty
noExistentials = isEmptyVarSet (tyVarsOfType ty')
noUniversals = null tvs
= tyConTyVars tc \\ dc_vars
tyConPhantomTyVars _ = []
--- Is this defined elsewhere?
--- Generalize the type: find all free tyvars and wrap in the appropiate ForAll.
-sigmaType :: Type -> Type
-sigmaType ty = mkSigmaTy (varSetElems$ tyVarsOfType ty) [] ty
+type QuantifiedType = ([TyVar], Type) -- Make the free type variables explicit
+quantifyType :: Type -> QuantifiedType
+-- Generalize the type: find all free tyvars and wrap in the appropiate ForAll.
+quantifyType ty = (varSetElems (tyVarsOfType ty), ty)
mapMif :: Monad m => (a -> Bool) -> (a -> m a) -> [a] -> m [a]
mapMif pred f xx = sequence $ mapMif_ pred f xx
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