import TyCon
import Coercion
import VarSet
-import Var
import Name
import UniqFM
import Outputable
pprFamInst :: FamInst -> SDoc
pprFamInst famInst
= hang (pprFamInstHdr famInst)
- 2 (ptext (sLit "--") <+> pprNameLoc (getName famInst))
+ 2 (vcat [ ifPprDebug (ptext (sLit "Coercion axiom:") <+> pp_ax)
+ , ptext (sLit "--") <+> pprNameLoc (getName famInst)])
+ where
+ pp_ax = case tyConFamilyCoercion_maybe (fi_tycon famInst) of
+ Just ax -> ppr ax
+ Nothing -> ptext (sLit "<not there!>")
pprFamInstHdr :: FamInst -> SDoc
pprFamInstHdr (FamInst {fi_tycon = rep_tc})
-- anything else would be difficult to test for at this stage.
conflicting old_fam_inst subst
| isAlgTyCon fam = True
- | otherwise = not (old_rhs `tcEqType` new_rhs)
+ | otherwise = not (old_rhs `eqType` new_rhs)
where
old_tycon = famInstTyCon old_fam_inst
old_tvs = tyConTyVars old_tycon
go rec_nts ty | Just ty' <- coreView ty -- Expand synonyms
= go rec_nts ty'
- go rec_nts (TyConApp tc tys) -- Expand newtypes
- | Just co_con <- newTyConCo_maybe tc -- See Note [Expanding newtypes]
- = if tc `elem` rec_nts -- in Type.lhs
+ go rec_nts (TyConApp tc tys)
+ | isNewTyCon tc -- Expand newtypes
+ = if tc `elem` rec_nts -- See Note [Expanding newtypes] in Type.lhs
then Nothing
- else let nt_co = mkTyConApp co_con tys
- in add_co nt_co rec_nts' nt_rhs
- where
- nt_rhs = newTyConInstRhs tc tys
- rec_nts' | isRecursiveTyCon tc = tc:rec_nts
- | otherwise = rec_nts
-
- go rec_nts (TyConApp tc tys) -- Expand open tycons
- | isFamilyTyCon tc
- , (ACo co, ty) <- normaliseTcApp env tc tys
- = -- The ACo says "something happened"
- -- Note that normaliseType fully normalises, but it has do to so
- -- to be sure that
- add_co co rec_nts ty
+ else let nt_co = mkAxInstCo (newTyConCo tc) tys
+ in add_co nt_co rec_nts' nt_rhs
+
+ | isFamilyTyCon tc -- Expand open tycons
+ , (co, ty) <- normaliseTcApp env tc tys
+ -- Note that normaliseType fully normalises,
+ -- but it has do to so to be sure that
+ , not (isReflCo co)
+ = add_co co rec_nts ty
+ where
+ nt_rhs = newTyConInstRhs tc tys
+ rec_nts' | isRecursiveTyCon tc = tc:rec_nts
+ | otherwise = rec_nts
go _ _ = Nothing
add_co co rec_nts ty
= case go rec_nts ty of
Nothing -> Just (co, ty)
- Just (co', ty') -> Just (mkTransCoercion co co', ty')
+ Just (co', ty') -> Just (mkTransCo co co', ty')
---------------
-normaliseTcApp :: FamInstEnvs -> TyCon -> [Type] -> (CoercionI, Type)
+normaliseTcApp :: FamInstEnvs -> TyCon -> [Type] -> (Coercion, Type)
normaliseTcApp env tc tys
| isFamilyTyCon tc
, tyConArity tc <= length tys -- Unsaturated data families are possible
= let -- A matching family instance exists
rep_tc = famInstTyCon fam_inst
co_tycon = expectJust "lookupFamInst" (tyConFamilyCoercion_maybe rep_tc)
- co = mkTyConApp co_tycon inst_tys
- first_coi = mkTransCoI tycon_coi (ACo co)
- (rest_coi, nty) = normaliseType env (mkTyConApp rep_tc inst_tys)
- fix_coi = mkTransCoI first_coi rest_coi
+ co = mkAxInstCo co_tycon inst_tys
+ first_coi = mkTransCo tycon_coi co
+ (rest_coi,nty) = normaliseType env (mkTyConApp rep_tc inst_tys)
+ fix_coi = mkTransCo first_coi rest_coi
in
(fix_coi, nty)
- | otherwise
+ | otherwise -- No unique matching family instance exists;
+ -- we do not do anything
= (tycon_coi, TyConApp tc ntys)
where
-- Normalise the arg types so that they'll match
-- when we lookup in in the instance envt
(cois, ntys) = mapAndUnzip (normaliseType env) tys
- tycon_coi = mkTyConAppCoI tc cois
+ tycon_coi = mkTyConAppCo tc cois
---------------
normaliseType :: FamInstEnvs -- environment with family instances
-> Type -- old type
- -> (CoercionI, Type) -- (coercion,new type), where
+ -> (Coercion, Type) -- (coercion,new type), where
-- co :: old-type ~ new_type
-- Normalise the input type, by eliminating *all* type-function redexes
--- Returns with IdCo if nothing happens
+-- Returns with Refl if nothing happens
normaliseType env ty
| Just ty' <- coreView ty = normaliseType env ty'
normaliseType env (AppTy ty1 ty2)
= let (coi1,nty1) = normaliseType env ty1
(coi2,nty2) = normaliseType env ty2
- in (mkAppTyCoI coi1 coi2, mkAppTy nty1 nty2)
+ in (mkAppCo coi1 coi2, mkAppTy nty1 nty2)
normaliseType env (FunTy ty1 ty2)
= let (coi1,nty1) = normaliseType env ty1
(coi2,nty2) = normaliseType env ty2
- in (mkFunTyCoI coi1 coi2, mkFunTy nty1 nty2)
+ in (mkFunCo coi1 coi2, mkFunTy nty1 nty2)
normaliseType env (ForAllTy tyvar ty1)
= let (coi,nty1) = normaliseType env ty1
- in (mkForAllTyCoI tyvar coi, ForAllTy tyvar nty1)
+ in (mkForAllCo tyvar coi, ForAllTy tyvar nty1)
normaliseType _ ty@(TyVarTy _)
- = (IdCo ty,ty)
+ = (Refl ty,ty)
normaliseType env (PredTy predty)
= normalisePred env predty
---------------
-normalisePred :: FamInstEnvs -> PredType -> (CoercionI,Type)
+normalisePred :: FamInstEnvs -> PredType -> (Coercion,Type)
normalisePred env (ClassP cls tys)
- = let (cois,tys') = mapAndUnzip (normaliseType env) tys
- in (mkClassPPredCoI cls cois, PredTy $ ClassP cls tys')
+ = let (cos,tys') = mapAndUnzip (normaliseType env) tys
+ in (mkPredCo $ ClassP cls cos, PredTy $ ClassP cls tys')
normalisePred env (IParam ipn ty)
- = let (coi,ty') = normaliseType env ty
- in (mkIParamPredCoI ipn coi, PredTy $ IParam ipn ty')
+ = let (co,ty') = normaliseType env ty
+ in (mkPredCo $ (IParam ipn co), PredTy $ IParam ipn ty')
normalisePred env (EqPred ty1 ty2)
- = let (coi1,ty1') = normaliseType env ty1
- (coi2,ty2') = normaliseType env ty2
- in (mkEqPredCoI coi1 coi2, PredTy $ EqPred ty1' ty2')
+ = let (co1,ty1') = normaliseType env ty1
+ (co2,ty2') = normaliseType env ty2
+ in (mkPredCo $ (EqPred co1 co2), PredTy $ EqPred ty1' ty2')
\end{code}
projects / ghc-hetmet.git / blobdiff