[sigc] Expected results of tests/test_functor_traits and visit_each behavior?

[Ryan Beasley <rbeasley vmware com>]

Hi all, 

I'm observing some odd behavior with one of libsigc++'s tests, and I'm wondering whether there's a problem 
with my patch or the test itself.

====
  sigc::visit_each(
    print(),
    sigc::compose(                         > A
      sigc::bind(sigc::ptr_fun3(&foo),    \
                 sigc::ref(a),             > B
                 i),                      /
      sigc::ptr_fun1(&bar)));              > C

  util->check_result(result_stream, "hit all targets: other other ");
====

It appears that unmodified visit_each doesn't dig into sigc::compose's parameters, so it fails to visit each 
of the leaf types individually.  With my patch, I'm observing different visitor output, but which I believe 
to be correct.

  Expected "hit all targets: other other "
  Got      "hit all targets: other trackable int: 1other "

So, who's wrong?  Me, the test, or both?

====
Type of A
---------
  sigc::compose1_functor<B, C>

  Visiting results in
     visit_each<T_action, B>(_A_action, _A_target.functor_); (_A_target.functor_ is instance of B.)
     visit_each<T_action, C>(_A_action, _A_target.get_);     (_A_target.get_ is instance of C.)
     
Type of B
---------
  sigc::bind_functor<
    -1,
    sigc::pointer_functor3<int, int, int, void>,            > type D
    sigc::reference_wrapper<{anonymous}::A>,                > type E
    int, (5 sigc::nils)>

  Visiting results in

    visit_each<T_action, sigc::pointer_functor3<int, int, int, void> >(_A_action, _A_target.functor_);
    visit_each<T_action, sigc::reference_wrapper<{anonymous}::A> >(_A_action, _A_target.bound1_);
    visit_each<T_action, int>(T_action, _A_target.bound2_);

  Visiting type D leads to
    print<D> -> "other"
  
  Visiting type E leads to
     visit_each<{anonymous}::print, sigc::bound_argument<sigc::reference_wrapper<{anonymous}::A> > >
      \--- visit_each<{anonymous}::print, sigc::limit_reference<{anonymous}::A, false> >
       \--- visit_each<{anonymous}::print, {anonymous}::A>
        \--- with_trackable<::A, true> -> "trackable"

  Visiting int leads to
    print<int> -> "int 1"
     
Type of C
---------
  sigc::pointer_functor1<int, void>

  Visiting results in
    visit_each<T_action, sigc::pointer_functor1<int, void> >(_A_action, _A_target.functor_);

    print<C> -> "other"

1. https://bugzilla.gnome.org/show_bug.cgi?id=724496