This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 119a. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.
2025-12-20
The grammar fortype-id in 11.3 [class.name] paragraph1 has two problems. First, the fact that we allow anabstract-pack-declarator makes some uses oftype-id(template arguments, alignment specifiers, exception-specifications)ambiguous:T... could be parsed either as atype-id,including the ellipsis, or as thetype-idT with afollowing ellipsis. There does not appear to be any rule todisambiguate these parses.
The other problem is that we do not allow parentheses in anabstract-pack-declarator, which makes
template<typename...Ts> void f(Ts (&...)[4]);
ill-formed because(&...)() is not anabstract-pack-declarator. There is implementation varianceon this point.