Jonathan Turkanis wrote:
The case you're interested in is
const std::string h() { return "hello"; } BOOST_STATIC_ASSERT(!BOOST_IS_LVALUE(h()));
which now fails, except on GCC 3.4 :( Are you sure GCC is wrong here?
Not 100% sure, but I'm inclined to think so. The reason is the second overload of lvalue_test2: template<typename T> type_traits::yes_type lvalue_test2( T&, int, typename enable_if< is_const<T> >::type* = 0 ); Given an expression of type "const rvalue-type", the expression will successfully bind to the T& with T deduced as "const rvalue-type". Then, enable_if< is_const<T> > will succeed, so this overload is chosen over the one with the elipses. That's causing the false positive (true negative). Seems to me that Arkadiy has run up against the same problem with BOOST_TYPEOF_PRESERVE_LVALUE, which also gets this case wrong (according to the docs). -- Eric Niebler Boost Consulting www.boost-consulting.com