Hello, Just installed Boost and Visual Studio 2017 a few days ago. Here is a bug when building with Hana's "basic_tuple.hpp" header with Visual Studio 2017: In basic_tuple.hpp: template <> struct drop_front_impl<basic_tuple_tag> { template <std::size_t N, typename Xs, std::size_t ...i> static constexpr auto drop_front_helper(Xs&& xs, std::index_sequence<i...>) { return hana::make_basic_tuple( detail::ebo_get<detail::bti<i+N>>(static_cast<Xs&&>(xs))... ); } template <typename Xs, typename N> static constexpr auto apply(Xs&& xs, N const&) { constexpr std::size_t len = detail::decay<Xs>::type::size_; return drop_front_helper<N::value>(static_cast<Xs&&>(xs), std::make_index_sequence< N::value < len ? len - N::value : 0 >{}); //<Bug here - line 197 of basic_tuple.hpp } }; Upon building with "basic_tuple.hpp", the line highlighted in green reports an error: "syntax error: unexpected token ')', expected 'id-expression'". Focus on the line above that one: N::value < len ? len - N::value : 0 If you add parentheses, the error goes away: (N::value < len) ? len - N::value : 0 A similar bug occurs - and is fixed likewise - in the "string.hpp" header file at line 275, that is: template <> struct drop_front_impl<string_tag> { ... template <char ...xs, typename N> static constexpr auto apply(string<xs...> const& s, N const&) { return helper<N::value>(s, std::make_index_sequence< N::value < sizeof...(xs) ? sizeof...(xs) - N::value : 0 >{}); //<bug here - line 275 of string.hpp } I'm not sure if this is a Microsoft compiler issue (I will post to them as well), but I feel like someone should add those parentheses (and then some) to the line since it is safer - the "<" can be easily confused for a template bracket instead of a less-than sign by a parser. Daniel Chen Infinera