X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypes%2FType.lhs;h=cf38146eb10d59b2c7b16691d72fdd35dba5fab0;hb=8690b84f0bbcae6351d1a664d96db9bc60b81b0f;hp=d80bd52c0ee6cb948ca508af51a93bb04aceebe4;hpb=c4ec8f2a77894af1c6160c4e8ad5625ab62f0bea;p=ghc-hetmet.git

diff --git a/compiler/types/Type.lhs b/compiler/types/Type.lhs
index d80bd52..cf38146 100644
--- a/compiler/types/Type.lhs
+++ b/compiler/types/Type.lhs
@@ -36,7 +36,6 @@ module Type (
 	mkTyConApp, mkTyConTy, 
 	tyConAppTyCon, tyConAppArgs, 
 	splitTyConApp_maybe, splitTyConApp, 
-        splitNewTyConApp_maybe, splitNewTyConApp,
 
         mkForAllTy, mkForAllTys, splitForAllTy_maybe, splitForAllTys, 
 	applyTy, applyTys, applyTysD, isForAllTy, dropForAlls,
@@ -45,7 +44,7 @@ module Type (
 	newTyConInstRhs,
 	
 	-- (Type families)
-        tyFamInsts,
+        tyFamInsts, predFamInsts,
 
         -- (Source types)
         mkPredTy, mkPredTys, mkFamilyTyConApp,
@@ -534,20 +533,6 @@ splitTyConApp_maybe (TyConApp tc tys) = Just (tc, tys)
 splitTyConApp_maybe (FunTy arg res)   = Just (funTyCon, [arg,res])
 splitTyConApp_maybe _                 = Nothing
 
--- | Sometimes we do NOT want to look through a @newtype@.  When case matching
--- on a newtype we want a convenient way to access the arguments of a @newtype@
--- constructor so as to properly form a coercion, and so we use 'splitNewTyConApp'
--- instead of 'splitTyConApp_maybe'
-splitNewTyConApp :: Type -> (TyCon, [Type])
-splitNewTyConApp ty = case splitNewTyConApp_maybe ty of
-			Just stuff -> stuff
-			Nothing	   -> pprPanic "splitNewTyConApp" (ppr ty)
-splitNewTyConApp_maybe :: Type -> Maybe (TyCon, [Type])
-splitNewTyConApp_maybe ty | Just ty' <- tcView ty = splitNewTyConApp_maybe ty'
-splitNewTyConApp_maybe (TyConApp tc tys) = Just (tc, tys)
-splitNewTyConApp_maybe (FunTy arg res)   = Just (funTyCon, [arg,res])
-splitNewTyConApp_maybe _                 = Nothing
-
 newTyConInstRhs :: TyCon -> [Type] -> Type
 -- ^ Unwrap one 'layer' of newtype on a type constructor and it's arguments, using an 
 -- eta-reduced version of the @newtype@ if possible
@@ -902,6 +887,14 @@ tyFamInsts (TyConApp tc tys)
 tyFamInsts (FunTy ty1 ty2)      = tyFamInsts ty1 ++ tyFamInsts ty2
 tyFamInsts (AppTy ty1 ty2)      = tyFamInsts ty1 ++ tyFamInsts ty2
 tyFamInsts (ForAllTy _ ty)      = tyFamInsts ty
+tyFamInsts (PredTy pty)         = predFamInsts pty
+
+-- | Finds type family instances occuring in a predicate type after expanding 
+-- synonyms.
+predFamInsts :: PredType -> [(TyCon, [Type])]
+predFamInsts (ClassP _cla tys) = concat (map tyFamInsts tys)
+predFamInsts (IParam _ ty)     = tyFamInsts ty
+predFamInsts (EqPred ty1 ty2)  = tyFamInsts ty1 ++ tyFamInsts ty2
 \end{code}
 
 
@@ -1162,14 +1155,16 @@ coreEqType t1 t2
 
 \begin{code}
 tcEqType :: Type -> Type -> Bool
--- ^ Type equality on source types. Does not look through @newtypes@ or 'PredType's
+-- ^ Type equality on source types. Does not look through @newtypes@ or 
+-- 'PredType's, but it does look through type synonyms.
 tcEqType t1 t2 = isEqual $ cmpType t1 t2
 
 tcEqTypes :: [Type] -> [Type] -> Bool
 tcEqTypes tys1 tys2 = isEqual $ cmpTypes tys1 tys2
 
 tcCmpType :: Type -> Type -> Ordering
--- ^ Type ordering on source types. Does not look through @newtypes@ or 'PredType's
+-- ^ Type ordering on source types. Does not look through @newtypes@ or 
+-- 'PredType's, but it does look through type synonyms.
 tcCmpType t1 t2 = cmpType t1 t2
 
 tcCmpTypes :: [Type] -> [Type] -> Ordering