unions are not anonymous

diff --git a/tests/59-choice-extended-OK.asn1.-P b/tests/59-choice-extended-OK.asn1.-P
index 391cbca..f7f8a2c 100644
--- a/tests/59-choice-extended-OK.asn1.-P
+++ b/tests/59-choice-extended-OK.asn1.-P
@@ -23,7 +23,7 @@
 
 typedef struct Choice {
 	Choice_PR present;
-	union {
+	union Choice_u {
 		INTEGER_t	 a;
 		/*
 		 * This type is extensible,