[Bug c++/7412] [DR 106] References to references

[dgregor at gcc dot gnu dot org]

------- Comment #5 from dgregor at gcc dot gnu dot org  2007-05-30 19:59 -------
The rvalue references patch (PR 29939) also implements reference collapsing as
described in core issue 106.

Unfortunately, however, Wolfgang's test case does not work even with reference
collapsing due to an interaction with library issue 109
(http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#109), which means
that instantiating a binder with a reference type results in errors like the
following:

/Volumes/scratch/dgregor/gcc0x-install/lib/gcc/powerpc-apple-darwin8.9.0/4.3.0/../../../../include/c++/4.3.0/bits/stl_function.h:
In instantiation of 'std::binder2nd<std::pointer_to_binary_function<const int&,
const int&, void> >':
honk.cpp:4:   instantiated from here
/Volumes/scratch/dgregor/gcc0x-install/lib/gcc/powerpc-apple-darwin8.9.0/4.3.0/../../../../include/c++/4.3.0/bits/stl_function.h:445:
error: 'typename _Operation::result_type
std::binder2nd<_Operation>::operator()(typename
_Operation::first_argument_type&) const [with _Operation =
std::pointer_to_binary_function<const int&, const int&, void>]' cannot be
overloaded
/Volumes/scratch/dgregor/gcc0x-install/lib/gcc/powerpc-apple-darwin8.9.0/4.3.0/../../../../include/c++/4.3.0/bits/stl_function.h:439:
error: with 'typename _Operation::result_type
std::binder2nd<_Operation>::operator()(const typename
_Operation::first_argument_type&) const [with _Operation =
std::pointer_to_binary_function<const int&, const int&, void>]'

With some work on the library side, we should be able to fix this problem. But,
I consider that a separate issue.


-- 

dgregor at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dgregor at gcc dot gnu dot
                   |                            |org
   Last reconfirmed|2006-03-05 03:54:05         |2007-05-30 19:59:36
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=7412