mkWantedConstraints, deCanonicaliseWanted,
makeGivens, makeSolvedByInst,
- CtFlavor (..), isWanted, isGiven, isDerived, isDerivedSC, isDerivedByInst,
+ CtFlavor (..), isWanted, isGiven, isDerived,
isGivenCt, isWantedCt, pprFlavorArising,
isFlexiTcsTv,
import FamInst
import FamInstEnv
-import NameSet ( addOneToNameSet )
-
import qualified TcRnMonad as TcM
import qualified TcMType as TcM
import qualified TcEnv as TcM
( checkWellStaged, topIdLvl, tcLookupFamInst, tcGetDefaultTys )
import TcType
-import Module
import DynFlags
import Coercion
-- these wanteds
| Wanted WantedLoc -- We have no evidence bindings for this constraint.
-data DerivedOrig = DerSC | DerInst
+data DerivedOrig = DerSC | DerInst | DerSelf
-- Deriveds are either superclasses of other wanteds or deriveds, or partially
--- solved wanteds from instances.
+-- solved wanteds from instances, or 'self' dictionaries containing yet wanted
+-- superclasses.
instance Outputable CtFlavor where
ppr (Given _) = ptext (sLit "[Given]")
isDerived (Derived {}) = True
isDerived _ = False
-isDerivedSC :: CtFlavor -> Bool
-isDerivedSC (Derived _ DerSC) = True
-isDerivedSC _ = False
-
-isDerivedByInst :: CtFlavor -> Bool
-isDerivedByInst (Derived _ DerInst) = True
-isDerivedByInst _ = False
-
pprFlavorArising :: CtFlavor -> SDoc
pprFlavorArising (Derived wl _) = pprArisingAt wl
pprFlavorArising (Wanted wl) = pprArisingAt wl
chase_ev assocs trg curr_grav visited (EvCoercion co)
= chase_co assocs trg curr_grav visited co
- chase_ev assocs trg curr_grav visited (EvDFunApp _ _ ev_vars)
- = do { chase_results <- mapM (chase_ev_var assocs trg (curr_grav+1) visited) ev_vars
- ; return (comb_chase_res Nothing chase_results) }
+ chase_ev assocs trg curr_grav visited (EvDFunApp _ _ _ev_vars ev_deps)
+ = do { chase_results <- mapM (chase_ev_var assocs trg (curr_grav+1) visited) ev_deps
+ -- Notice that we chase the ev_deps and not the ev_vars
+ -- See Note [Dependencies in self dictionaries] in TcSimplify
+ ; return (comb_chase_res Nothing chase_results) }
chase_co assocs trg curr_grav visited co
= -- Look for all the coercion variables in the coercion
text "witness" <+> ppr dfun_id
<+> ppr (idType dfun_id) ])
-- Record that this dfun is needed
- ; record_dfun_usage dfun_id
- ; return $ MatchInstSingle (dfun_id, inst_tys)
+ ; return $ MatchInstSingle (dfun_id, inst_tys)
} ;
(matches, unifs) -- More than one matches
-> do { traceTcS "matchClass multiple matches, deferring choice"
}
}
}
- where record_dfun_usage :: Id -> TcS ()
- record_dfun_usage dfun_id
- = do { hsc_env <- getTopEnv
- ; let dfun_name = idName dfun_id
- dfun_mod = ASSERT( isExternalName dfun_name )
- nameModule dfun_name
- ; if isInternalName dfun_name || -- Internal name => defined in this module
- modulePackageId dfun_mod /= thisPackage (hsc_dflags hsc_env)
- then return () -- internal, or in another package
- else do updInstUses dfun_id
- }
-
- updInstUses :: Id -> TcS ()
- updInstUses dfun_id
- = do { tcg_env <- getGblEnv
- ; wrapTcS $ TcM.updMutVar (tcg_inst_uses tcg_env)
- (`addOneToNameSet` idName dfun_id)
- }
-
-matchFam :: TyCon
+
+matchFam :: TyCon
-> [Type]
-> TcS (MatchInstResult (TyCon, [Type]))
matchFam tycon args