-eqTy :: Type -> Type -> Bool
-
-eqTy t1 t2 =
- eq nullTyVarEnv nullUVarEnv t1 t2
- where
- eq tve uve (TyVarTy tv1) (TyVarTy tv2) =
- tv1 == tv2 ||
- case (lookupTyVarEnv tve tv1) of
- Just tv -> tv == tv2
- Nothing -> False
- eq tve uve (AppTy f1 a1) (AppTy f2 a2) =
- eq tve uve f1 f2 && eq tve uve a1 a2
- eq tve uve (TyConTy tc1 u1) (TyConTy tc2 u2) =
- tc1 == tc2 && eqUsage uve u1 u2
-
- eq tve uve (FunTy f1 a1 u1) (FunTy f2 a2 u2) =
- eq tve uve f1 f2 && eq tve uve a1 a2 && eqUsage uve u1 u2
- eq tve uve (FunTy f1 a1 u1) t2 =
- -- Expand t1 just in case t2 matches that version
- eq tve uve (AppTy (AppTy (TyConTy mkFunTyCon u1) f1) a1) t2
- eq tve uve t1 (FunTy f2 a2 u2) =
- -- Expand t2 just in case t1 matches that version
- eq tve uve t1 (AppTy (AppTy (TyConTy mkFunTyCon u2) f2) a2)
-
- eq tve uve (DictTy c1 t1 u1) (DictTy c2 t2 u2) =
- c1 == c2 && eq tve uve t1 t2 && eqUsage uve u1 u2
- eq tve uve t1@(DictTy _ _ _) t2 =
- eq tve uve (expandTy t1) t2 -- Expand the dictionary and try again
- eq tve uve t1 t2@(DictTy _ _ _) =
- eq tve uve t1 (expandTy t2) -- Expand the dictionary and try again
-
- eq tve uve (SynTy tc1 ts1 t1) (SynTy tc2 ts2 t2) =
- (tc1 == tc2 && and (zipWith (eq tve uve) ts1 ts2) && length ts1 == length ts2)
- || eq tve uve t1 t2
- eq tve uve (SynTy _ _ t1) t2 =
- eq tve uve t1 t2 -- Expand the abbrevation and try again
- eq tve uve t1 (SynTy _ _ t2) =
- eq tve uve t1 t2 -- Expand the abbrevation and try again
-
- eq tve uve (ForAllTy tv1 t1) (ForAllTy tv2 t2) =
- eq (addOneToTyVarEnv tve tv1 tv2) uve t1 t2
- eq tve uve (ForAllUsageTy u1 b1 t1) (ForAllUsageTy u2 b2 t2) =
- eqBounds uve b1 b2 && eq tve (addOneToUVarEnv uve u1 u2) t1 t2
-
- eq _ _ _ _ = False
-
- eqBounds uve [] [] = True
- eqBounds uve (u1:b1) (u2:b2) = eqUVar uve u1 u2 && eqBounds uve b1 b2
- eqBounds uve _ _ = False
+eqType t1 t2 = eq_ty emptyVarEnv t1 t2
+eqKind = eqType -- No worries about looking
+eqUsage = eqType -- through source types for these two
+
+-- Look through Notes
+eq_ty env (NoteTy _ t1) t2 = eq_ty env t1 t2
+eq_ty env t1 (NoteTy _ t2) = eq_ty env t1 t2
+
+-- Look through SourceTy. This is where the looping danger comes from
+eq_ty env (SourceTy sty1) t2 = eq_ty env (sourceTypeRep sty1) t2
+eq_ty env t1 (SourceTy sty2) = eq_ty env t1 (sourceTypeRep sty2)
+
+-- 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