diff --git a/src/api/api_opt.cpp b/src/api/api_opt.cpp
index d38b5e38c..20d228ebc 100644
--- a/src/api/api_opt.cpp
+++ b/src/api/api_opt.cpp
@@ -148,7 +148,8 @@ extern "C" {
         param_descrs descrs;
         to_optimize_ref(o).collect_param_descrs(descrs);
         to_params(p)->m_params.validate(descrs);
-        to_optimize_ref(o).updt_params(to_param_ref(p));
+        params_ref pr = to_param_ref(p);
+        to_optimize_ref(o).updt_params(pr);
         Z3_CATCH;
     }