mkSynTy,
- repType, typePrimRep, coreView,
+ repType, typePrimRep, coreView, deepCoreView,
mkForAllTy, mkForAllTys, splitForAllTy_maybe, splitForAllTys,
applyTy, applyTys, isForAllTy, dropForAlls,
tidyTopType, tidyPred,
-- Comparison
- eqType,
+ coreEqType, tcEqType, tcEqTypes, tcCmpType, tcCmpTypes,
+ tcEqPred, tcCmpPred, tcEqTypeX,
-- Seq
seqType, seqTypes,
import CmdLineOpts ( opt_DictsStrict )
import SrcLoc ( noSrcLoc )
import Unique ( Uniquable(..) )
-import Util ( mapAccumL, seqList, lengthIs, snocView )
+import Util ( mapAccumL, seqList, lengthIs, snocView, thenCmp, isEqual )
import Outputable
import UniqSet ( sizeUniqSet ) -- Should come via VarSet
import Maybe ( isJust )
coreView (TyConApp tc tys) = expandNewTcApp tc tys
coreView ty = Nothing
+deepCoreView :: Type -> Type
+-- Apply coreView recursively
+deepCoreView ty
+ | Just ty' <- coreView ty = deepCoreView ty'
+deepCoreView (TyVarTy tv) = TyVarTy tv
+deepCoreView (TyConApp tc tys) = TyConApp tc (map deepCoreView tys)
+deepCoreView (AppTy t1 t2) = AppTy (deepCoreView t1) (deepCoreView t2)
+deepCoreView (FunTy t1 t2) = FunTy (deepCoreView t1) (deepCoreView t2)
+deepCoreView (ForAllTy tv ty) = ForAllTy tv (deepCoreView ty)
+ -- No NoteTy, no PredTy
+
expandNewTcApp :: TyCon -> [Type] -> Maybe Type
-- A local helper function (not exported)
-- Expands *the outermoset level of* a newtype application to
%************************************************************************
%* *
-\subsection{Equality on types}
+ Comparison of types
+ (We don't use instances so that we know where it happens)
%* *
%************************************************************************
-Comparison; don't use instances so that we know where it happens.
-Look through newtypes but not usage types.
+Two flavours:
+
+* tcEqType, tcCmpType do *not* look through newtypes, PredTypes
+* coreEqType *does* look through them
Note that eqType can respond 'False' for partial applications of newtypes.
Consider
newtype Parser m a = MkParser (Foogle m a)
-
Does
Monad (Parser m) `eqType` Monad (Foogle m)
-
Well, yes, but eqType won't see that they are the same.
I don't think this is harmful, but it's soemthing to watch out for.
+First, the external interface
+
+\begin{code}
+coreEqType :: Type -> Type -> Bool
+coreEqType t1 t2 = isEqual $ cmpType (deepCoreView t1) (deepCoreView t2)
+
+tcEqType :: Type -> Type -> Bool
+tcEqType t1 t2 = isEqual $ cmpType t1 t2
+
+tcEqTypes :: [Type] -> [Type] -> Bool
+tcEqTypes tys1 tys2 = isEqual $ cmpTypes tys1 tys2
+
+tcCmpType :: Type -> Type -> Ordering
+tcCmpType t1 t2 = cmpType t1 t2
+
+tcCmpTypes :: [Type] -> [Type] -> Ordering
+tcCmpTypes tys1 tys2 = cmpTypes tys1 tys2
+
+tcEqPred :: PredType -> PredType -> Bool
+tcEqPred p1 p2 = isEqual $ cmpPred p1 p2
+
+tcCmpPred :: PredType -> PredType -> Ordering
+tcCmpPred p1 p2 = cmpPred p1 p2
+
+tcEqTypeX :: RnEnv2 -> Type -> Type -> Bool
+tcEqTypeX env t1 t2 = isEqual $ cmpTypeX env t1 t2
+\end{code}
+
+Now here comes the real worker
+
\begin{code}
-eqType t1 t2 = eq_ty emptyVarEnv t1 t2
+cmpType :: Type -> Type -> Ordering
+cmpType t1 t2 = cmpTypeX rn_env t1 t2
+ where
+ rn_env = mkRnEnv2 (mkInScopeSet (tyVarsOfType t1 `unionVarSet` tyVarsOfType t2))
+
+cmpTypes :: [Type] -> [Type] -> Ordering
+cmpTypes ts1 ts2 = cmpTypesX rn_env ts1 ts2
+ where
+ rn_env = mkRnEnv2 (mkInScopeSet (tyVarsOfTypes ts1 `unionVarSet` tyVarsOfTypes ts2))
+
+cmpPred :: PredType -> PredType -> Ordering
+cmpPred p1 p2 = cmpPredX rn_env p1 p2
+ where
+ rn_env = mkRnEnv2 (mkInScopeSet (tyVarsOfPred p1 `unionVarSet` tyVarsOfPred p2))
--- Look through Notes, PredTy, newtype applications
-eq_ty env t1 t2 | Just t1' <- coreView t1 = eq_ty env t1' t2
-eq_ty env t1 t2 | Just t2' <- coreView t2 = eq_ty env t1 t2'
+cmpTypeX :: RnEnv2 -> Type -> Type -> Ordering -- Main workhorse
-- NB: we *cannot* short-cut the newtype comparison thus:
--- eq_ty env (NewTcApp tc1 tys1) (NewTcApp tc2 tys2)
--- | (tc1 == tc2) = (eq_tys env tys1 tys2)
+-- eqTypeX env (NewTcApp tc1 tys1) (NewTcApp tc2 tys2)
+-- | (tc1 == tc2) = (eqTypeXs env tys1 tys2)
--
-- Consider:
-- newtype T a = MkT [a]
-- but we can only expand saturated newtypes, so just comparing
-- T with [] won't do.
--- The rest is plain sailing
-eq_ty env (TyVarTy tv1) (TyVarTy tv2) = case lookupVarEnv env tv1 of
- Just tv1a -> tv1a == tv2
- Nothing -> tv1 == tv2
-eq_ty env (ForAllTy tv1 t1) (ForAllTy tv2 t2)
- | tv1 == tv2 = eq_ty (delVarEnv env tv1) t1 t2
- | otherwise = eq_ty (extendVarEnv env tv1 tv2) t1 t2
-eq_ty env (AppTy s1 t1) (AppTy s2 t2) = (eq_ty env s1 s2) && (eq_ty env t1 t2)
-eq_ty env (FunTy s1 t1) (FunTy s2 t2) = (eq_ty env s1 s2) && (eq_ty env t1 t2)
-eq_ty env (TyConApp tc1 tys1) (TyConApp tc2 tys2) = (tc1 == tc2) && (eq_tys env tys1 tys2)
-eq_ty env t1 t2 = False
-
-eq_tys env [] [] = True
-eq_tys env (t1:tys1) (t2:tys2) = (eq_ty env t1 t2) && (eq_tys env tys1 tys2)
-eq_tys env tys1 tys2 = False
+cmpTypeX env (TyVarTy tv1) (TyVarTy tv2) = rnOccL env tv1 `compare` rnOccR env tv2
+cmpTypeX env (ForAllTy tv1 t1) (ForAllTy tv2 t2) = cmpTypeX (rnBndr2 env tv1 tv2) t1 t2
+cmpTypeX env (AppTy s1 t1) (AppTy s2 t2) = cmpTypeX env s1 s2 `thenCmp` cmpTypeX env t1 t2
+cmpTypeX env (FunTy s1 t1) (FunTy s2 t2) = cmpTypeX env s1 s2 `thenCmp` cmpTypeX env t1 t2
+cmpTypeX env (PredTy p1) (PredTy p2) = cmpPredX env p1 p2
+cmpTypeX env (TyConApp tc1 tys1) (TyConApp tc2 tys2) = (tc1 `compare` tc2) `thenCmp` cmpTypesX env tys1 tys2
+cmpTypeX env (NoteTy _ t1) t2 = cmpTypeX env t1 t2
+cmpTypeX env t1 (NoteTy _ t2) = cmpTypeX env t1 t2
+
+ -- Deal with the rest: TyVarTy < AppTy < FunTy < TyConApp < ForAllTy < PredTy
+cmpTypeX env (AppTy _ _) (TyVarTy _) = GT
+
+cmpTypeX env (FunTy _ _) (TyVarTy _) = GT
+cmpTypeX env (FunTy _ _) (AppTy _ _) = GT
+
+cmpTypeX env (TyConApp _ _) (TyVarTy _) = GT
+cmpTypeX env (TyConApp _ _) (AppTy _ _) = GT
+cmpTypeX env (TyConApp _ _) (FunTy _ _) = GT
+
+cmpTypeX env (ForAllTy _ _) (TyVarTy _) = GT
+cmpTypeX env (ForAllTy _ _) (AppTy _ _) = GT
+cmpTypeX env (ForAllTy _ _) (FunTy _ _) = GT
+cmpTypeX env (ForAllTy _ _) (TyConApp _ _) = GT
+
+cmpTypeX env (PredTy _) t2 = GT
+
+cmpTypeX env _ _ = LT
+
+-------------
+cmpTypesX :: RnEnv2 -> [Type] -> [Type] -> Ordering
+cmpTypesX env [] [] = EQ
+cmpTypesX env (t1:tys1) (t2:tys2) = cmpTypeX env t1 t2 `compare` cmpTypesX env tys1 tys2
+cmpTypesX env [] tys = LT
+cmpTypesX env ty [] = GT
+
+-------------
+cmpPredX :: RnEnv2 -> PredType -> PredType -> Ordering
+cmpPredX env (IParam n1 ty1) (IParam n2 ty2) = (n1 `compare` n2) `thenCmp` cmpTypeX env ty1 ty2
+ -- Compare types as well as names for implicit parameters
+ -- This comparison is used exclusively (I think) for the
+ -- finite map built in TcSimplify
+cmpPredX env (ClassP c1 tys1) (ClassP c2 tys2) = (c1 `compare` c2) `thenCmp` cmpTypesX env tys1 tys2
+cmpPredX env (IParam _ _) (ClassP _ _) = LT
+cmpPredX env (ClassP _ _) (IParam _ _) = GT
+\end{code}
+
+PredTypes are used as a FM key in TcSimplify,
+so we take the easy path and make them an instance of Ord
+
+\begin{code}
+instance Eq PredType where { (==) = tcEqPred }
+instance Ord PredType where { compare = tcCmpPred }
\end{code}
projects / ghc-hetmet.git / blobdiff