unions are not anonymous

diff --git a/tests/89-bit-string-enum-OK.asn1.-P b/tests/89-bit-string-enum-OK.asn1.-P
index 0ab33be..3cd1f35 100644
--- a/tests/89-bit-string-enum-OK.asn1.-P
+++ b/tests/89-bit-string-enum-OK.asn1.-P
@@ -19,7 +19,7 @@
 
 typedef struct T {
 	T_PR present;
-	union {
+	union T_u {
 		BIT_STRING_t	 bs;
 	} choice;