X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypes%2FTyCon.lhs;h=1464fabcc7d3aa7223d99b4ed88546b3267f8b33;hb=27897431cf24d4bde04b15947440c7205f2d703c;hp=40cfa069b7a68f737d6ac27502b0e03166dc2287;hpb=feb584b7ffd49827ff2b6e716965cfdcd344570e;p=ghc-hetmet.git

diff --git a/compiler/types/TyCon.lhs b/compiler/types/TyCon.lhs
index 40cfa06..1464fab 100644
--- a/compiler/types/TyCon.lhs
+++ b/compiler/types/TyCon.lhs
@@ -14,9 +14,10 @@ module TyCon(
 	SynTyConRhs(..),
 
 	isFunTyCon, isUnLiftedTyCon, isProductTyCon, 
-	isAlgTyCon, isDataTyCon, isSynTyCon, isNewTyCon, isPrimTyCon,
-	isEnumerationTyCon, isGadtSyntaxTyCon, isOpenTyCon, isAssocTyCon,
-	makeTyConAssoc,
+	isAlgTyCon, isDataTyCon, isSynTyCon, isNewTyCon, isClosedNewTyCon,
+	isPrimTyCon, 
+	isEnumerationTyCon, isGadtSyntaxTyCon, isOpenTyCon,
+	assocTyConArgPoss_maybe, isTyConAssoc, setTyConArgPoss,
 	isTupleTyCon, isUnboxedTupleTyCon, isBoxedTupleTyCon, tupleTyConBoxity,
 	isRecursiveTyCon, newTyConRep, newTyConRhs, newTyConCo,
 	isHiBootTyCon, isSuperKindTyCon,
@@ -68,6 +69,7 @@ import Class		( Class )
 import BasicTypes	( Arity, RecFlag(..), Boxity(..), isBoxed )
 import Name		( Name, nameUnique, NamedThing(getName) )
 import PrelNames	( Unique, Uniquable(..) )
+import Maybe		( isJust )
 import Maybes		( orElse )
 import Outputable
 import FastString
@@ -101,7 +103,12 @@ data TyCon
 					--		   algTyConRhs.NewTyCon
 					-- But not over the data constructors
 
-        tyConIsAssoc :: Bool,           -- for families: declared in a class?
+        tyConArgPoss :: Maybe [Int],    -- for associated families: for each
+					-- tyvar in the AT decl, gives the
+					-- position of that tyvar in the class
+					-- argument list (starting from 0).
+					-- NB: Length is less than tyConArity
+					--     if higher kind signature.
 	
 	algTcSelIds :: [Id],  		-- Its record selectors (empty if none)
 
@@ -143,7 +150,14 @@ data TyCon
 	tyConArity   :: Arity,
 
 	tyConTyVars  :: [TyVar],	-- Bound tyvars
-        tyConIsAssoc :: Bool,           -- for families: declared in a class?
+
+        tyConArgPoss :: Maybe [Int],    -- for associated families: for each
+					-- tyvar in the AT decl, gives the
+					-- position of that tyvar in the class
+					-- argument list (starting from 0).
+					-- NB: Length is less than tyConArity
+					--     if higher kind signature.
+	
 	synTcRhs     :: SynTyConRhs	-- Expanded type in here
     }
 
@@ -404,7 +418,7 @@ mkAlgTyCon name kind tyvars stupid rhs sel_ids parent is_rec gen_info gadt_syn
 	tyConKind	 = kind,
 	tyConArity	 = length tyvars,
 	tyConTyVars	 = tyvars,
-	tyConIsAssoc	 = False,
+	tyConArgPoss	 = Nothing,
 	algTcStupidTheta = stupid,
 	algTcRhs         = rhs,
 	algTcSelIds	 = sel_ids,
@@ -474,7 +488,7 @@ mkSynTyCon name kind tyvars rhs
 	tyConKind = kind,
 	tyConArity = length tyvars,
 	tyConTyVars = tyvars,
-	tyConIsAssoc = False,
+	tyConArgPoss = Nothing,
 	synTcRhs = rhs
     }
 
@@ -537,13 +551,23 @@ isDataTyCon tc@(AlgTyCon {algTcRhs = rhs})
 	OpenNewTyCon  -> False
 	NewTyCon {}   -> False
 	AbstractTyCon -> pprPanic "isDataTyCon" (ppr tc)
-
 isDataTyCon (TupleTyCon {tyConBoxed = boxity}) = isBoxed boxity
 isDataTyCon other = False
 
 isNewTyCon :: TyCon -> Bool
-isNewTyCon (AlgTyCon {algTcRhs = NewTyCon {}}) = True 
-isNewTyCon other			       = False
+isNewTyCon (AlgTyCon {algTcRhs = rhs}) = case rhs of
+					   OpenNewTyCon -> True
+					   NewTyCon {}  -> True
+					   _	        -> False
+isNewTyCon other			= False
+
+-- This is an important refinement as typical newtype optimisations do *not*
+-- hold for newtype families.  Why?  Given a type `T a', if T is a newtype
+-- family, there is no unique right hand side by which `T a' can be replaced
+-- by a cast.
+--
+isClosedNewTyCon :: TyCon -> Bool
+isClosedNewTyCon tycon = isNewTyCon tycon && not (isOpenTyCon tycon)
 
 isProductTyCon :: TyCon -> Bool
 -- A "product" tycon
@@ -580,15 +604,18 @@ isOpenTyCon (AlgTyCon {algTcRhs = OpenDataTyCon }) = True
 isOpenTyCon (AlgTyCon {algTcRhs = OpenNewTyCon  }) = True
 isOpenTyCon _					   = False
 
-isAssocTyCon :: TyCon -> Bool
-isAssocTyCon (AlgTyCon { tyConIsAssoc = isAssoc }) = isAssoc
-isAssocTyCon (SynTyCon { tyConIsAssoc = isAssoc }) = isAssoc
-isAssocTyCon _                                     = False
+assocTyConArgPoss_maybe :: TyCon -> Maybe [Int]
+assocTyConArgPoss_maybe (AlgTyCon { tyConArgPoss = poss }) = poss
+assocTyConArgPoss_maybe (SynTyCon { tyConArgPoss = poss }) = poss
+assocTyConArgPoss_maybe _                                  = Nothing
+
+isTyConAssoc :: TyCon -> Bool
+isTyConAssoc = isJust . assocTyConArgPoss_maybe
 
-makeTyConAssoc :: TyCon -> TyCon
-makeTyConAssoc tc@(AlgTyCon {}) = tc { tyConIsAssoc = True }
-makeTyConAssoc tc@(SynTyCon {}) = tc { tyConIsAssoc = True }
-makeTyConAssoc tc = pprPanic "makeTyConAssoc" (ppr tc)
+setTyConArgPoss :: TyCon -> [Int] -> TyCon
+setTyConArgPoss tc@(AlgTyCon {}) poss = tc { tyConArgPoss = Just poss }
+setTyConArgPoss tc@(SynTyCon {}) poss = tc { tyConArgPoss = Just poss }
+setTyConArgPoss tc _ = pprPanic "setTyConArgPoss" (ppr tc)
 
 isTupleTyCon :: TyCon -> Bool
 -- The unit tycon didn't used to be classed as a tuple tycon
@@ -730,7 +757,10 @@ newTyConRep (AlgTyCon {tyConTyVars = tvs, algTcRhs = NewTyCon { nt_rep = rep }})
 newTyConRep tycon = pprPanic "newTyConRep" (ppr tycon)
 
 newTyConCo :: TyCon -> Maybe TyCon
-newTyConCo (AlgTyCon {tyConTyVars = tvs, algTcRhs = NewTyCon { nt_co = co }}) = co
+newTyConCo (AlgTyCon {tyConTyVars = tvs, algTcRhs = NewTyCon { nt_co = co }})
+  = co
+newTyConCo (AlgTyCon {tyConTyVars = tvs, algTcRhs = OpenNewTyCon})
+  = Nothing
 newTyConCo tycon = pprPanic "newTyConCo" (ppr tycon)
 
 tyConPrimRep :: TyCon -> PrimRep