diff --git a/ghc/interpreter/stgSubst.c b/ghc/interpreter/stgSubst.c
index 98b92f1372cf7d13df4518b217aeb87af49f82bb..07c3d3ecedecfe7701f4a6ade8979090beffa680 100644
--- a/ghc/interpreter/stgSubst.c
+++ b/ghc/interpreter/stgSubst.c
@@ -9,8 +9,8 @@
  * included in the distribution.
  *
  * $RCSfile: stgSubst.c,v $
- * $Revision: 1.8 $
- * $Date: 2000/03/23 14:54:21 $
+ * $Revision: 1.9 $
+ * $Date: 2000/04/28 13:03:47 $
  * ------------------------------------------------------------------------*/
 
 #include "hugsbasictypes.h"
@@ -107,6 +107,7 @@ StgExpr substExpr( List sub, StgExpr e )
             break;
     case STGVAR:
     case NAME:
+    case TUPLE:
             return substVar(sub,e);
     default:
             internal("substExpr");