Re: PR 4051

[Jason Merrill <jason_merrill at redhat dot com>]

>>>>> "Phil" == Phil Edwards <pedwards@disaster.jaj.com> writes:

> On Wed, Aug 22, 2001 at 07:49:16AM -0300, Alexandre Oliva wrote:
>> Since ostream_iterator is defined in namespace std, the context in
>> which the expression that outputs a pair to the ostream is that
>> namespace, where a number of operator<<s that hide the definition in
>> the global namespace exist.  Since the argumetns have type
>> std::ostream and std::pair<int,int>, Koenig lookup only searches
>> namespace std too.  So, the definition of ::operator<< isn't
>> considered.  Does this make sense to anyone?

> Wow, that's twisted.  :-)  I thought the usual unqualified name lookup rules
> (which hit global scope pretty early) were executed before Koenig lookup.

They are.  But as Alexandre says, the unqualified lookup starts in std,
finds a definition, and stops.  It never hits global scope.

> But yeah, simply surrounding the op<< in the example code with 'namespace std
> {' and '}' allows the code to compile cleanly, even though the function isn't
> a template specialization (and thus has no business being in std).  Weird.

It is a specialization of sorts...

Jason