X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcType.lhs;h=bfff2c8e552a5b9b67c969dff19c4f5ac3294dc8;hb=ad17cf6e34b6ab03f19914e7d2c1262b073db3fa;hp=e7083acb7437cba1235605fce83a16d6e992d82e;hpb=cd290fc88d35d5a32c994664baa56a5eae250e9e;p=ghc-hetmet.git

diff --git a/compiler/typecheck/TcType.lhs b/compiler/typecheck/TcType.lhs
index e7083ac..bfff2c8 100644
--- a/compiler/typecheck/TcType.lhs
+++ b/compiler/typecheck/TcType.lhs
@@ -28,7 +28,8 @@ module TcType (
   UserTypeCtxt(..), pprUserTypeCtxt,
   TcTyVarDetails(..), BoxInfo(..), pprTcTyVarDetails,
   MetaDetails(Flexi, Indirect), SkolemInfo(..), pprSkolTvBinding, pprSkolInfo,
-  isImmutableTyVar, isSkolemTyVar, isMetaTyVar, isBoxyTyVar, isSigTyVar, isExistentialTyVar, 
+  isImmutableTyVar, isSkolemTyVar, isMetaTyVar, isBoxyTyVar, 
+  isSigTyVar, isExistentialTyVar,  isTyConableTyVar,
   metaTvRef, 
   isFlexi, isIndirect, 
 
@@ -478,11 +479,26 @@ instance Outputable MetaDetails where
 %************************************************************************
 
 \begin{code}
-isImmutableTyVar, isSkolemTyVar, isExistentialTyVar, isBoxyTyVar, isMetaTyVar :: TyVar -> Bool
+isImmutableTyVar :: TyVar -> Bool
+
 isImmutableTyVar tv
   | isTcTyVar tv = isSkolemTyVar tv
   | otherwise    = True
 
+isTyConableTyVar, isSkolemTyVar, isExistentialTyVar, 
+  isBoxyTyVar, isMetaTyVar :: TcTyVar -> Bool 
+
+isTyConableTyVar tv	
+	-- True of a meta-type variable tha can be filled in 
+	-- with a type constructor application; in particular,
+	-- not a SigTv
+  = ASSERT( isTcTyVar tv) 
+    case tcTyVarDetails tv of
+	MetaTv BoxTv      _ -> True
+	MetaTv TauTv      _ -> True
+	MetaTv (SigTv {}) _ -> False
+	SkolemTv {}	    -> False
+	
 isSkolemTyVar tv 
   = ASSERT( isTcTyVar tv )
     case tcTyVarDetails tv of