diff --git a/.gitattributes b/.gitattributes
index 0016ee0e9c82333adaa1fdecdaeae55a42511e1a..884509883fcbc1f5582e5bfa087cfbed75516ab6 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -767,7 +767,6 @@ testfont binary
 /src/object.h foreign_ident
 /src/opcodes.c foreign_ident
 /src/opcodes.h foreign_ident
-/src/operators.c foreign_ident
 /src/operators.h foreign_ident
 /src/patch_cc1.c foreign_ident
 /src/peep.c foreign_ident
diff --git a/src/operators.c b/src/operators.c
index d6e2be45fee7c3b46bf8c2a85c60dc3f17b509c8..9c4cc19d821428b012e48d0dfa4c30704069ec0a 100644
--- a/src/operators.c
+++ b/src/operators.c
@@ -2,7 +2,7 @@
 || This file is part of Pike. For copyright information see COPYRIGHT.
 || Pike is distributed under GPL, LGPL and MPL. See the file COPYING
 || for more information.
-|| $Id: operators.c,v 1.258 2010/05/27 23:16:59 mast Exp $
+|| $Id$
 */
 
 #include "global.h"
@@ -124,7 +124,7 @@ void index_no_free(struct svalue *to,struct svalue *what,struct svalue *ind)
 
 #ifdef AUTO_BIGNUM
   case T_INT:
-    if (ind->type == T_STRING) {
+    if (ind->type == T_STRING && !IS_UNDEFINED (what)) {
       INT_TYPE val = what->u.integer;
 
       convert_svalue_to_bignum(what);