diff --git a/tests/tests-asn1c-compiler/125-bitstring-constraint-OK.asn1.-P b/tests/tests-asn1c-compiler/125-bitstring-constraint-OK.asn1.-P
index f267409..b522fe2 100644
--- a/tests/tests-asn1c-compiler/125-bitstring-constraint-OK.asn1.-P
+++ b/tests/tests-asn1c-compiler/125-bitstring-constraint-OK.asn1.-P
@@ -47,8 +47,7 @@
 	}
 	
 	/* Replace with underlying type checker */
-	td->check_constraints = asn_DEF_BIT_STRING.check_constraints;
-	return td->check_constraints(td, sptr, ctfailcb, app_key);
+	return td->op->check_constraints(td, sptr, ctfailcb, app_key);
 }
 
 /*
@@ -64,17 +63,8 @@
 asn_TYPE_descriptor_t asn_DEF_T = {
 	"T",
 	"T",
-	BIT_STRING_free,
-	BIT_STRING_print,
-	BIT_STRING_compare,
+	&asn_OP_BIT_STRING,
 	T_constraint,
-	BIT_STRING_decode_ber,
-	BIT_STRING_encode_der,
-	BIT_STRING_decode_xer,
-	BIT_STRING_encode_xer,
-	0, 0,	/* No OER support, use "-gen-OER" to enable */
-	0, 0,	/* No PER support, use "-gen-PER" to enable */
-	0,	/* Use generic outmost tag fetcher */
 	asn_DEF_T_tags_1,
 	sizeof(asn_DEF_T_tags_1)
 		/sizeof(asn_DEF_T_tags_1[0]), /* 1 */