diff --git a/pgxn/neon/communicator_new.c b/pgxn/neon/communicator_new.c
index d64e30af96..51a3358bae 100644
--- a/pgxn/neon/communicator_new.c
+++ b/pgxn/neon/communicator_new.c
@@ -344,7 +344,7 @@ callback_set_my_latch_unsafe(void)
  * FIXME: The logic from neon_get_request_lsns() needs to go here, except for
  * the last-written LSN cache stuff, which is managed by the rust code now.
  */
-uint64
+uint64_t
 callback_get_request_lsn_unsafe(void)
 {
 	/*