diff --git a/core/safe_refcount.h b/core/safe_refcount.h
index 7519329f2a5..c34d84f55b3 100644
--- a/core/safe_refcount.h
+++ b/core/safe_refcount.h
@@ -36,6 +36,7 @@
 #if !defined(NO_THREADS)
 
 #include <atomic>
+#include <type_traits>
 
 // Design goals for these classes:
 // - No automatic conversions or arithmetic operators,