Seems I can't "unforget" erroneously forgotten files, so will have to forget them and then re-add them
// Copyright 2000 John Maddock (john@johnmaddock.co.uk)
// Copyright 2000 Jeremy Siek (jsiek@lsc.nd.edu)
// Copyright 1999, 2000 Jaakko Jarvi (jaakko.jarvi@cs.utu.fi)
//
// Use, modification and distribution are subject to the Boost Software License,
// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt).
//
// See http://www.boost.org/libs/type_traits for most recent version including documentation.
#ifndef BOOST_TT_CONVERSION_TRAITS_HPP_INCLUDED
#define BOOST_TT_CONVERSION_TRAITS_HPP_INCLUDED
#include <boost/type_traits/is_convertible.hpp>
#endif // BOOST_TT_CONVERSION_TRAITS_HPP_INCLUDED