Carsten Gräser
--- a/dune/common/rangeutilities.hh
+++ b/dune/common/rangeutilities.hh
      return iterator(rawRange_.end(), &f_);
    }

+    /**
+     * \brief Obtain the size of the range
+     *
+     * This is only available if the underlying range
+     * provides a size() method. In this case size()
+     * just forwards to the underlying range's size() method.
+     *
+     * Attention: Don't select the template parameters explicitly.
+     * They are only used to implement SFINAE.
+     */
+    template<class Dummy=R,
+      class = void_t<decltype(std::declval<Dummy>().size())>>
+    std::size_t size() const