X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypes%2FTyCon.lhs;h=2e7427c89fe87c6dd87867928e5a646646d61275;hb=36d207aa8c9cedbf58e739178971292048bd41d0;hp=fc27995d95c3d63d8044c9218fe8f7f9a0936e6a;hpb=ab22f4e6456820c1b5169d75f5975a94e61f54ce;p=ghc-hetmet.git

diff --git a/compiler/types/TyCon.lhs b/compiler/types/TyCon.lhs
index fc27995..2e7427c 100644
--- a/compiler/types/TyCon.lhs
+++ b/compiler/types/TyCon.lhs
@@ -13,7 +13,7 @@ module TyCon(
 	tyConPrimRep,
 
 	AlgTyConRhs(..), visibleDataCons, 
-        AlgTyConParent(..), hasParent,
+        AlgTyConParent(..), 
 	SynTyConRhs(..),
 
 	isFunTyCon, isUnLiftedTyCon, isProductTyCon, 
@@ -73,7 +73,6 @@ import Class
 import BasicTypes
 import Name
 import PrelNames
-import Maybe
 import Maybes
 import Outputable
 import FastString
@@ -115,6 +114,8 @@ data TyCon
 					-- argument list (starting from 0).
 					-- NB: Length is less than tyConArity
 					--     if higher kind signature.
+					-- NB: Just _ <=> associated (not
+					--		  toplevel) family
 	
 	algTcSelIds :: [Id],  		-- Its record selectors (empty if none)
 
@@ -173,7 +174,8 @@ data TyCon
 	tyConUnique   :: Unique,
 	tyConName     :: Name,
 	tyConKind     :: Kind,
-	tyConArity    :: Arity,
+	tyConArity    :: Arity,		-- SLPJ Oct06: I'm not sure what the significance
+					--	       of the arity of a primtycon is!
 
 	primTyConRep  :: PrimRep,
 			-- Many primitive tycons are unboxed, but some are
@@ -279,10 +281,6 @@ data AlgTyConParent = -- An ordinary type constructor has no parent.
 						-- the representation type
 						-- with the type instance
 
-hasParent :: AlgTyConParent -> Bool
-hasParent NoParentTyCon = False
-hasParent _other        = True
-
 data SynTyConRhs
   = OpenSynTyCon Kind	-- Type family: *result* kind given
   | SynonymTyCon Type   -- Mentioning head type vars.  Acts as a template for
@@ -545,8 +543,8 @@ isAlgTyCon (TupleTyCon {}) = True
 isAlgTyCon other 	   = False
 
 isDataTyCon :: TyCon -> Bool
--- isDataTyCon returns True for data types that are represented by
--- heap-allocated constructors.
+-- isDataTyCon returns True for data types that are definitely
+-- represented by heap-allocated constructors.
 -- These are srcutinised by Core-level @case@ expressions, and they
 -- get info tables allocated for them.
 --	True for all @data@ types
@@ -558,7 +556,7 @@ isDataTyCon tc@(AlgTyCon {algTcRhs = rhs})
 	DataTyCon {}  -> True
 	OpenNewTyCon  -> False
 	NewTyCon {}   -> False
-	AbstractTyCon -> pprPanic "isDataTyCon" (ppr tc)
+	AbstractTyCon -> False	-- We don't know, so return False
 isDataTyCon (TupleTyCon {tyConBoxed = boxity}) = isBoxed boxity
 isDataTyCon other = False
 
@@ -674,11 +672,24 @@ isCoercionTyCon :: TyCon -> Bool
 isCoercionTyCon (CoercionTyCon {}) = True
 isCoercionTyCon other              = False
 
+-- Identifies implicit tycons that, in particular, do not go into interface
+-- files (because they are implicitly reconstructed when the interface is
+-- read).
+--
+-- Note that 
+--
+-- * associated families are implicit, as they are re-constructed from
+--   the class declaration in which they reside, and 
+-- * family instances are *not* implicit as they represent the instance body
+--   (similar to a dfun does that for a class instance).
+--
 isImplicitTyCon :: TyCon -> Bool
-isImplicitTyCon SynTyCon{}                     = False
-isImplicitTyCon AlgTyCon{algTcParent = parent} = hasParent parent
-isImplicitTyCon other                          = True
-        -- catches: FunTyCon, TupleTyCon, PrimTyCon, 
+isImplicitTyCon tycon | isTyConAssoc tycon           = True
+		      | isSynTyCon tycon	     = False
+		      | isAlgTyCon tycon	     = isClassTyCon tycon ||
+						       isTupleTyCon tycon
+isImplicitTyCon _other                               = True
+        -- catches: FunTyCon, PrimTyCon, 
         -- CoercionTyCon, SuperKindTyCon
 \end{code}