FamInstEnv: Type checked family instance declarations
\begin{code}
-{-# OPTIONS -w #-}
--- The above warning supression flag is a temporary kludge.
--- While working on this module you are encouraged to remove it and fix
--- any warnings in the module. See
--- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
--- for details
-
module FamInstEnv (
FamInst(..), famInstTyCon, famInstTyVars,
pprFamInst, pprFamInstHdr, pprFamInsts,
import VarSet
import Var
import Name
-import OccName
-import SrcLoc
import UniqFM
import Outputable
import Maybes
famInstTyCon :: FamInst -> TyCon
famInstTyCon = fi_tycon
+famInstTyVars :: FamInst -> TyVarSet
famInstTyVars = fi_tvs
\end{code}
-- See explanation at @InstEnv.bind_fn@.
--
+bind_fn :: TyVar -> BindFlag
bind_fn tv | isTcTyVar tv && isExistentialTyVar tv = Skolem
| otherwise = BindMe
\end{code}
-- to be sure that
add_co co rec_nts ty
- go rec_nts ty = Nothing
+ go _ _ = Nothing
add_co co rec_nts ty
= case go rec_nts ty of
-- No unique matching family instance exists;
-- we do not do anything
- other -> (tycon_coi, TyConApp tc ntys)
+ _ -> (tycon_coi, TyConApp tc ntys)
---------------
normaliseType :: FamInstEnvs -- environment with family instances
-> Type -- old type
normaliseType env ty
| Just ty' <- coreView ty = normaliseType env ty'
-normaliseType env ty@(TyConApp tc tys)
+normaliseType env (TyConApp tc tys)
= normaliseTcApp env tc tys
-normaliseType env ty@(AppTy ty1 ty2)
+normaliseType env (AppTy ty1 ty2)
= let (coi1,nty1) = normaliseType env ty1
(coi2,nty2) = normaliseType env ty2
in (mkAppTyCoI nty1 coi1 nty2 coi2, AppTy nty1 nty2)
-normaliseType env ty@(FunTy ty1 ty2)
+normaliseType env (FunTy ty1 ty2)
= let (coi1,nty1) = normaliseType env ty1
(coi2,nty2) = normaliseType env ty2
in (mkFunTyCoI nty1 coi1 nty2 coi2, FunTy nty1 nty2)
-normaliseType env ty@(ForAllTy tyvar ty1)
+normaliseType env (ForAllTy tyvar ty1)
= let (coi,nty1) = normaliseType env ty1
in (mkForAllTyCoI tyvar coi,ForAllTy tyvar nty1)
-normaliseType env ty@(NoteTy note ty1)
+normaliseType env (NoteTy note ty1)
= let (coi,nty1) = normaliseType env ty1
- in (mkNoteTyCoI note coi,NoteTy note nty1)
-normaliseType env ty@(TyVarTy _)
+ in (coi,NoteTy note nty1)
+normaliseType _ ty@(TyVarTy _)
= (IdCo,ty)
normaliseType env (PredTy predty)
- = normalisePred env predty
+ = normalisePred env predty
---------------
normalisePred :: FamInstEnvs -> PredType -> (CoercionI,Type)