Building using CMake on my OSX box, as well as using clang on Linux (with stdlib=libc++) fails with static_asserts in test_tuple_transform_each.cc ("unexpected transform_each()ed tuple type"). Upon further investigation, it appears that

decltype(t_transformed) is tuple<const string, const string, const string>

while

decltype(t_expected) is tuple<string, string, string>

I wonder if there is a std::remove_cv missing somewhere.