This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 115e. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.
2024-11-11
[Accepted at the November, 2020 meeting as part of paper P1787R6 and moved to DR at the February, 2021 meeting.]
The status of an example like the following is unclear in the current Standard:
struct B {
void f();
};
template<typename T> struct S: T {
using B::f;
};
9.9 [namespace.udecl] does not deal explicitly with dependent base classes, but does say in paragraph 3,
In a using-declaration used as a member-declaration, the nested-name-specifier shall name a base class of the class being defined. If such a using-declaration names a constructor, the nested-name-specier shall name a direct base class of the class being defined; otherwise it introduces the set of declarations found by member name lookup (6.5.2 [class.member.lookup], 6.5.5.2 [class.qual]).
In the definition of S, B::f is not a dependent name but resolves to an apparently unrelated class. However, because S could be instantiated as S<B>, presumably 13.8 [temp.res] paragraph 8 would apply:
No diagnostic shall be issued for a template definition for which a valid specialization can be generated.
Note also the resolution of issue 515, which permitted a similar use of a dependent base class named with a non-dependent name.