Extended TyCon and friends to represent family declarations

[ghc-hetmet.git] / compiler / typecheck / TcType.lhs

diff --git a/compiler/typecheck/TcType.lhs b/compiler/typecheck/TcType.lhs
index a382808..a53c9ed 100644 (file)
--- a/compiler/typecheck/TcType.lhs
+++ b/compiler/typecheck/TcType.lhs
@@ -169,7 +169,8 @@ import Type         (       -- Re-exports
                          pprType, pprParendType, pprTyThingCategory,
                          pprPred, pprTheta, pprThetaArrow, pprClassPred
                        )
-import TyCon           ( TyCon, isUnLiftedTyCon, isSynTyCon, synTyConDefn, tyConUnique )
+import TyCon           ( TyCon, isUnLiftedTyCon, isSynTyCon, isOpenTyCon,
+                         synTyConDefn, tyConUnique )    
 import DataCon         ( DataCon, dataConStupidTheta, dataConResTys )
 import Class           ( Class )
 import Var             ( TyVar, Id, isCoVar, isTcTyVar, mkTcTyVar, tyVarName, tyVarKind, tcTyVarDetails )
@@ -591,8 +592,9 @@ isTauTy other                 = False
 
 isTauTyCon :: TyCon -> Bool
 -- Returns False for type synonyms whose expansion is a polytype
-isTauTyCon tc | isSynTyCon tc = isTauTy (snd (synTyConDefn tc))
-             | otherwise     = True
+isTauTyCon tc 
+  | isSynTyCon tc && not (isOpenTyCon tc) = isTauTy (snd (synTyConDefn tc))
+  | otherwise                             = True
 
 ---------------
 isBoxyTy :: TcType -> Bool