static assert for boost::python::make_constructor

[jfalk]

You get a static assertion when using
boost::python::make_constructor together
with the call policy
return_value_policy<manage_new_object>()

Test case:
=====================================================
#include <boost/python.hpp>

namespace Test {
  using namespace boost::python;

  class Foo {
  };

  Foo *fooCreator() { return new Foo(); }

  BOOST_PYTHON_MODULE(Test)
  {
    class_<Foo>("Foo")
      .def("__init__", make_constructor(fooCreator,
return_value_policy<manage_new_object>()));
  }

} /* namespace Test */

Failure:
=====================================================
/usr/include/boost/python/make_constructor.hpp: In
instantiation of
`boost::python::detail::constructor_policy<boost::python::return_value_policy<boost::python::manage_new_object,
boost::python::default_call_policies> >':
/usr/include/boost/python/make_constructor.hpp:150:  
instantiated from `boost::python::api::object
boost::python::detail::make_constructor_aux(F, const
CallPolicies&, const Sig&) [with F = Test::Foo*(*)(),
CallPolicies =
boost::python::return_value_policy<boost::python::manage_new_object,
boost::python::default_call_policies>, Sig =
boost::mpl::vector1<Test::Foo*>]'
/usr/include/boost/python/make_constructor.hpp:236:  
instantiated from `boost::python::api::object
boost::python::make_constructor(F, const CallPolicies&)
[with F = Test::Foo*(*)(), CallPolicies =
boost::python::return_value_policy<boost::python::manage_new_object,
boost::python::default_call_policies>]'
boost-python-test.cpp:14:   instantiated from here
/usr/include/boost/python/make_constructor.hpp:106:
error: incomplete type `
   boost::STATIC_ASSERTION_FAILURE<false>' does not
have member `value'

Expected Result:
=====================================================
Should compile

[david_abrahams]

Logged In: YES 
user_id=52572

That's the expected behavior.  make_constructor supplies its
own return value policy that does the right thing, and the
assertion exists to let you know that any return value
policy you supply will be ignored. 

Admittedly the error message could be better, but we didn't
have the technology to make that improvement when the code
was written.