X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcType.lhs;h=7595a75de209b8af7d2cb2751d5f8feb9a9ef807;hb=3092ace710af6d63ea57394eba91d4edc5b7cb91;hp=59286304da952d9e6ea5c806f1d89ebb62be0776;hpb=43f19eec0ec4c507be2391d66ff53e79a8580561;p=ghc-hetmet.git

diff --git a/compiler/typecheck/TcType.lhs b/compiler/typecheck/TcType.lhs
index 5928630..7595a75 100644
--- a/compiler/typecheck/TcType.lhs
+++ b/compiler/typecheck/TcType.lhs
@@ -45,7 +45,8 @@ module TcType (
   tcSplitFunTy_maybe, tcSplitFunTys, tcFunArgTy, tcFunResultTy, tcSplitFunTysN,
   tcSplitTyConApp, tcSplitTyConApp_maybe, tcTyConAppTyCon, tcTyConAppArgs,
   tcSplitAppTy_maybe, tcSplitAppTy, tcSplitAppTys, repSplitAppTy_maybe,
-  tcValidInstHeadTy, tcGetTyVar_maybe, tcGetTyVar,
+  tcInstHeadTyNotSynonym, tcInstHeadTyAppAllTyVars,
+  tcGetTyVar_maybe, tcGetTyVar,
   tcSplitSigmaTy, tcMultiSplitSigmaTy, 
 
   ---------------------------------
@@ -442,17 +443,18 @@ pprSkolTvBinding :: TcTyVar -> SDoc
 -- or nothing if we don't have anything useful to say
 pprSkolTvBinding tv
   = ASSERT ( isTcTyVar tv )
-    ppr_details (tcTyVarDetails tv)
+    quotes (ppr tv) <+> ppr_details (tcTyVarDetails tv)
   where
-    ppr_details (MetaTv TauTv _)   = quotes (ppr tv) <+> ptext SLIT("is a meta type variable")
-    ppr_details (MetaTv BoxTv _)   = quotes (ppr tv) <+> ptext SLIT("is a boxy type variable")
+    ppr_details (MetaTv TauTv _)   	= ptext SLIT("is a meta type variable")
+    ppr_details (MetaTv BoxTv _)   	= ptext SLIT("is a boxy type variable")
     ppr_details (MetaTv (SigTv info) _) = ppr_skol info
     ppr_details (SkolemTv info)		= ppr_skol info
 
-    ppr_skol UnkSkol = empty	-- Unhelpful; omit
-    ppr_skol RuntimeUnkSkol = quotes (ppr tv) <+> ptext SLIT("is an unknown runtime type")
-    ppr_skol info    = quotes (ppr tv) <+> ptext SLIT("is bound by") 
-			<+> sep [pprSkolInfo info, nest 2 (ptext SLIT("at") <+> ppr (getSrcLoc tv))]
+    ppr_skol UnkSkol	    = empty	-- Unhelpful; omit
+    ppr_skol RuntimeUnkSkol = ptext SLIT("is an unknown runtime type")
+    ppr_skol info           = sep [ptext SLIT("is a rigid type variable bound by"),
+				   sep [pprSkolInfo info, 
+					 nest 2 (ptext SLIT("at") <+> ppr (getSrcLoc tv))]]
  
 pprSkolInfo :: SkolemInfo -> SDoc
 pprSkolInfo (SigSkol ctxt)   = pprUserTypeCtxt ctxt
@@ -715,9 +717,16 @@ tcSplitFunTys ty = case tcSplitFunTy_maybe ty of
 					  (args,res') = tcSplitFunTys res
 
 tcSplitFunTy_maybe :: Type -> Maybe (Type, Type)
-tcSplitFunTy_maybe ty | Just ty' <- tcView ty = tcSplitFunTy_maybe ty'
-tcSplitFunTy_maybe (FunTy arg res)  = Just (arg, res)
-tcSplitFunTy_maybe other	    = Nothing
+tcSplitFunTy_maybe ty | Just ty' <- tcView ty           = tcSplitFunTy_maybe ty'
+tcSplitFunTy_maybe (FunTy arg res) | not (isPredTy arg) = Just (arg, res)
+tcSplitFunTy_maybe other	  			= Nothing
+	-- Note the (not (isPredTy arg)) guard
+	-- Consider	(?x::Int) => Bool
+	-- We don't want to treat this as a function type!
+	-- A concrete example is test tc230:
+	--	f :: () -> (?p :: ()) => () -> ()
+	--
+	--	g = f () ()
 
 tcSplitFunTysN
 	:: TcRhoType 
@@ -782,14 +791,24 @@ tcSplitDFunHead tau
 	Just (ClassP clas tys) -> (clas, tys)
 	other -> panic "tcSplitDFunHead"
 
-tcValidInstHeadTy :: Type -> Bool
+tcInstHeadTyNotSynonym :: Type -> Bool
 -- Used in Haskell-98 mode, for the argument types of an instance head
 -- These must not be type synonyms, but everywhere else type synonyms
 -- are transparent, so we need a special function here
-tcValidInstHeadTy ty
+tcInstHeadTyNotSynonym ty
+  = case ty of
+	NoteTy _ ty     -> tcInstHeadTyNotSynonym ty
+	TyConApp tc tys -> not (isSynTyCon tc)
+	FunTy arg res   -> True
+	other		-> False
+
+tcInstHeadTyAppAllTyVars :: Type -> Bool
+-- Used in Haskell-98 mode, for the argument types of an instance head
+-- These must be a constructor applied to type variable arguments
+tcInstHeadTyAppAllTyVars ty
   = case ty of
-	NoteTy _ ty     -> tcValidInstHeadTy ty
-	TyConApp tc tys -> not (isSynTyCon tc) && ok tys
+	NoteTy _ ty     -> tcInstHeadTyAppAllTyVars ty
+	TyConApp _ tys  -> ok tys
 	FunTy arg res   -> ok [arg, res]
 	other		-> False
   where
@@ -1234,7 +1253,7 @@ legalFFITyCon tc
   = isUnLiftedTyCon tc || boxedMarshalableTyCon tc || tc == unitTyCon
 
 marshalableTyCon dflags tc
-  =  (dopt Opt_GlasgowExts dflags && isUnLiftedTyCon tc)
+  =  (dopt Opt_UnliftedFFITypes dflags && isUnLiftedTyCon tc)
   || boxedMarshalableTyCon tc
 
 boxedMarshalableTyCon tc