Hello, I am having problems using a multi_index_container in the context of a template class, and I am hoping someone here can help me. This is a condensed example: template<class T> struct C { typedef multi_index_container<T> SomeSet; SomeSet container; // I learned I need typename, since this is an implicit type typedef typename multi_index_container<T>::nth_index<0>::type SomeSetIndex; void f() { SomeSetIndex& index = container.get<0>(); } }; The typedef for SomeSetIndex did not compile. g++-4.2 reported (I stripped something from the message that I think is not relevant): error: non-template 'nth_index' used as template note: use 'multi_index_container<T, [stripped] >::template nth_index' to indicate that it is a template Now I (blindly) tried this declaration: typedef typename multi_index_container<T>::template nth_index<0>::type g++ gets past it, but now reports a syntax error in function f, when index gets initialised. Can someone please explain that first error message to me? Any help is appreciated. -J