David B. Held wrote:
"Daniel Wallin" <dalwan01@student.umu.se> wrote in message
No it should work as expected. This specialization forbids construction from lvalues, conversions too.
template<class U, BOOST_CONVERSION_PARAMETERS> struct cant_move_from_const< const smart_ptr<U, BOOST_CONVERSION_POLICIES>
;
I don't see how. This only gets "activated" during a call to:
template <typename P> smart_ptr(P&, cant_move...<>);
But, in this case:
smart_ptr<Base, destructive_copy> p( smart_ptr<Derived, destructive_copy>(new Derived) );
The better match is not smart_ptr(P&) but rather smart_ptr(smart_ptr<U>&), because the latter is more specialized. This seems to totally circumvent your system. Does the conversion c'tor also need to use the cant_move device? I.e.:
template <typename U, policies...> smart_ptr(smart_ptr<U, policies>&p, cant_move..);
No, it doesn't need to be the best match. The error is generated when the overload is considered during overload resolution. Whenever U is substituted by smart_ptr<U, ...> const the compilation fails.
<snip> If you are interested in trying to diagnose the problem yourself, I will try to update the sandbox with my working version.
Yes I can take a look at it. I only have access to gcc3.3.1 and and 2.95.3 though. -- Daniel Wallin