This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 115d. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.
2024-10-26
[Voted into the WP at the March, 2011 meeting as part of paper N3262.]
Consider the following example:
template<class T>
struct A {
template<class U>
friend struct A; // Which A?
};
Presumably the lookup for A in the friend declaration finds the injected-class-name of the template. However, according to 13.8.2 [temp.local] paragraph 1,
The injected-class-name can be used with or without a template-argument-list. When it is used without a template-argument-list, it is equivalent to the injected-class-name followed by the template-parameters of the class template enclosed in <>. When it is used with a template-argument-list, it refers to the specified class template specialization, which could be the current specialization or another specialization.
If that rule applies, then this example is ill-formed (because you can't have a template-argument-list in a class template declaration that is not a partial specialization).
Mike Miller: The injected-class-name has a dual nature, as described in 13.8.2 [temp.local], acting as either a template name or a class name, depending on the context; a template argument list forces the name to be interpreted as a template. It seems reasonable that in this example the injected-class-name has to be understood as referring to the class template; a template header is at least as strong a contextual indicator as a template argument list. However, the current wording doesn't say that.
(See also issue 1004.)
Proposed resolution (November, 2010) [SUPERSEDED]:
This issue is resolved by the resolution of issue 1004.