On 17/01/2008, Richard Guenther wrote:
Well, a language lawyer can probably clear things up. From a look
at the std it looks like w/o a previous declaration the above should
be invalid. And at a different point it suggests the decl becomes
available.
Yes, at the point of instantiation of Foo<int> the friend is declared,
and can then be found by ADL because Foo<int> is an associated type.
The reference parameter 'x' doesn't cause an instantiation, only 'weird' does.
However, see the discussion in section 9.2.2 of Vandevoorde and
Josuttis' C++ Templates book and the footnote saying the standard
isn't exactly clear.