diff --git a/unsupported/test/cxx11_tensor_fixed_size.cpp b/unsupported/test/cxx11_tensor_fixed_size.cpp
index 4c660de65..e6274f8eb 100644
--- a/unsupported/test/cxx11_tensor_fixed_size.cpp
+++ b/unsupported/test/cxx11_tensor_fixed_size.cpp
@@ -21,7 +21,7 @@ static void test_0d()
   TensorFixedSize<float, Sizes<>, RowMajor> scalar2;
   VERIFY_IS_EQUAL(scalar1.rank(), 0);
   VERIFY_IS_EQUAL(scalar1.size(), 1);
-  VERIFY_IS_EQUAL(array_prod(scalar1.dimensions()), 1);
+  VERIFY_IS_EQUAL(internal::array_prod(scalar1.dimensions()), 1);
 
   scalar1() = 7.0;
   scalar2() = 13.0;