diff --git a/src/tests/util/optional.cpp b/src/tests/util/optional.cpp
index b859c4b45..8b02b6885 100644
--- a/src/tests/util/optional.cpp
+++ b/src/tests/util/optional.cpp
@@ -5,6 +5,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Author: Leonardo de Moura
 */
 #include <iostream>
+#include <string>
 #include "util/test.h"
 #include "util/optional.h"
 using namespace lean;
diff --git a/src/util/lazy_list.h b/src/util/lazy_list.h
index f77ce0183..3dc7027ec 100644
--- a/src/util/lazy_list.h
+++ b/src/util/lazy_list.h
@@ -5,6 +5,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Author: Leonardo de Moura
 */
 #pragma once
+#include <utility>
 #include "util/debug.h"
 #include "util/rc.h"
 #include "util/optional.h"