diff --git a/drape/overlay_tree.cpp b/drape/overlay_tree.cpp
index 57a8a20117..41e9eb8233 100644
--- a/drape/overlay_tree.cpp
+++ b/drape/overlay_tree.cpp
@@ -154,8 +154,9 @@ void OverlayTree::Add(ref_ptr<OverlayHandle> handle)
     }
   }
 
-  int const rank = handle->GetOverlayRank();
-  ASSERT_LESS(rank, static_cast<int>(m_handles.size()), ());
+  ASSERT_GREATER_OR_EQUAL(handle->GetOverlayRank(), 0, ());
+  size_t const rank = static_cast<size_t>(handle->GetOverlayRank());
+  ASSERT_LESS(rank, m_handles.size(), ());
   m_handles[rank].emplace_back(handle);
 }