diff --git a/tests/Test_overflow.c b/tests/Test_overflow.c

index b276b6d..8cfe098 100644

--- a/tests/Test_overflow.c

+++ b/tests/Test_overflow.c

@@ -60,7 +60,7 @@ main (int argc, char **argv)

      rejected.  This limitation was introduced with libtasn1 2.12. */

   if (LONG_MAX > INT_MAX)

     {

-      unsigned long num = ((long) UINT_MAX) << 2;

+      unsigned long num = ((unsigned long) UINT_MAX) << 2;

       unsigned char der[20];

       int der_len;

       long l;