diff --git a/failtest/ref_5.cpp b/failtest/ref_5.cpp
new file mode 100644
index 0000000..846d527
--- /dev/null
+++ b/failtest/ref_5.cpp
@@ -0,0 +1,16 @@
+#include "../Eigen/Core"
+
+using namespace Eigen;
+
+void call_ref(Ref<VectorXf> a) { }
+
+int main()
+{
+  VectorXf a(10);
+  DenseBase<VectorXf> &ac(a);
+#ifdef EIGEN_SHOULD_FAIL_TO_BUILD
+  call_ref(ac);
+#else
+  call_ref(ac.derived());
+#endif
+}