Hello, The range metafunctions currently do not work on range reference types. For example, the following: #include <vector> #include typedef boost::range_iterator::type iter_t; Fails with the errors: In file included from lib/boost/boost/range/iterator.hpp:23:0,                  from lib/boost/boost/range/metafunctions.hpp:18,                  from test4.cpp:2: lib/boost/boost/mpl/eval_if.hpp: In instantiation of 'boost::mpl::eval_if_c, boost::range_mutable_iterator >': lib/boost/boost/range/iterator.hpp:72:63:   instantiated from 'boost::range_iterator' test4.cpp:4:49:   instantiated from here lib/boost/boost/mpl/eval_if.hpp:60:31: error: no type named 'type' in 'boost::mpl::eval_if_c, boost::range_mutable_iterator >::f_ {aka struct boost::range_mutable_iterator}' This behaviour is OK when you are doing things like this: template <typename Range> typename range_iterator<Range>::type some_function(const Range& r) { ... } because when called with a "const vector<T>&" argument, template argument deduction will deduce "Range" to be just "vector<T>", and this is what we call the metafunction on. Likewise, if some_function has a non-const version that takes a "Range&" argument, it works fine too. But in C++0x, rvalue references allow us to kill two birds with one stone and have just one function that accepts both const and non-const references: template <typename Range> typename range_iterator<Range>::type some_function(Range&& r) { ... } However, the template argument deduction rules for rvalue references are different: if the function is called with a "const vector<T>&" parameter, "Range" will be deduced as "const vector<T>&", i.e. the reference is preserved. But now range_iterator gives an error as indicated above, so we have to do something awkward and verbose like this: template <typename Range> typename range_iterator::type some_function(Range&& r) { ... } Could the range metafunctions be modified to accept range reference parameters and remove the reference themselves? Thanks, Nate.