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 6bda6a8..627c271 100644
--- a/tests/tests-asn1c-compiler/125-bitstring-constraint-OK.asn1.-P
+++ b/tests/tests-asn1c-compiler/125-bitstring-constraint-OK.asn1.-P
@@ -29,7 +29,7 @@
 /*** <<< CODE [T] >>> ***/
 
 int
-T_constraint(asn_TYPE_descriptor_t *td, const void *sptr,
+T_constraint(const asn_TYPE_descriptor_t *td, const void *sptr,
 			asn_app_constraint_failed_f *ctfailcb, void *app_key) {
 	const BIT_STRING_t *st = (const BIT_STRING_t *)sptr;