Do not use a reference in range-based for over IndexSet

diff --git a/include/deal.II/numerics/vector_tools_interpolate.templates.h b/include/deal.II/numerics/vector_tools_interpolate.templates.h
index b9dcad1d97676b7a195830e41a5d19d5c2e03f7e..ace617504164f5e9ecb6b04e0b71496b64e615be 100644 (file)
--- a/include/deal.II/numerics/vector_tools_interpolate.templates.h
+++ b/include/deal.II/numerics/vector_tools_interpolate.templates.h
@@ -599,7 +599,7 @@ namespace VectorTools
 
     // Compute the mean value of the sum which has been placed in
     // each entry of the output vector only at locally owned elements.
-    for (const auto &i : data_2.locally_owned_elements())
+    for (const auto i : data_2.locally_owned_elements())
       {
         const number touch_count_i =
           ::dealii::internal::ElementAccess<OutVector>::get(touch_count, i);