ifCtxt = hsIfaceCtxt (tcdCtxt decl),
ifCons = Unknown, ifRec = NonRecursive,
ifVrcs = [], ifGeneric = False }
+ -- I'm not sure that [] is right for ifVrcs, but
+ -- since we don't use them I'm not going to fiddle
hsIfaceDecl (TyClD decl@(ClassDecl {}))
= IfaceClass { ifName = rdrNameOcc (tcdName decl),
initial_oi :: NameEnv (TyCon, ArgVrcs)
initial_oi = mkNameEnv [(tyConName tc, (tc, initial tc))
| tc <- tycons]
- initial tc = if isAlgTyCon tc && isNothing (tyConDataCons_maybe tc) then
- -- make pessimistic assumption (and warn)
- abstractVrcs tc
- else
- replicate (tyConArity tc) (False,False)
+ initial tc = replicate (tyConArity tc) (False,False)
tcaoFix :: NameEnv (TyCon, ArgVrcs) -- initial ArgVrcs per tycon
-> NameEnv (TyCon, ArgVrcs) -- fixpointed ArgVrcs per tycon
-> ArgVrcs -- new ArgVrcs for tycon
tcaoIter oi tc | isAlgTyCon tc
- = if null data_cons then
- abstractVrcs tc -- Data types with no constructors
- else
- map (\v -> anyVrc (vrcInTy (lookup oi) v) argtys) vs
+ = map (\v -> anyVrc (vrcInTy (lookup oi) v) argtys) vs
where
data_cons = tyConDataCons tc
vs = tyConTyVars tc
Just (_, pms) -> pms
Nothing -> tyConArgVrcs tc
-- We use the already-computed result for tycons not in this SCC
-
-
-abstractVrcs :: TyCon -> ArgVrcs
-abstractVrcs tc =
-#ifdef DEBUG
- pprTrace "Vrc: abstract tycon:" (ppr tc) $
-#endif
- warn_abstract_vrcs `seq` replicate (tyConArity tc) (True,True)
-
-warn_abstract_vrcs
--- we pull the message out as a CAF so the warning only appears *once*
- = trace ("WARNING: tyConArgVrc info inaccurate due to unavailable constructors.\n"
- ++ " Use -fno-prune-tydecls to fix.") $
- ()
\end{code}
= DataCons [datacon] -- Its data constructors, with fully polymorphic types
-- A type can have zero constructors
- | Unknown -- We're importing this data type from an hi-boot file
- -- and we don't know what its constructors are
+ | Unknown -- Used only when We're importing this data type from an
+ -- hi-boot file, so we don't know what its constructors are
visibleDataCons (DataCons cs) = cs
visibleDataCons other = []
tyConDataConDetails :: TyCon -> DataConDetails DataCon
tyConDataConDetails (AlgTyCon {dataCons = cons}) = cons
tyConDataConDetails (TupleTyCon {dataCon = con}) = DataCons [con]
-tyConDataConDetails other = Unknown
+tyConDataConDetails other = pprPanic "tyConDataConDetails" (ppr other)
tyConDataCons :: TyCon -> [DataCon]
-- It's convenient for tyConDataCons to return the