This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 112e. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.
[Voted into the WP at the March, 2011 meeting as part of paper N3270.]
According to 13.7.4 [temp.variadic] paragraph 4,
A pack expansion is a sequence of tokens that names one or more parameter packs, followed by an ellipsis.
This is contradicted by 220.127.116.11 [expr.sizeof] paragraph 5, which describes sizeof...(Types) as an expansion, as well as the case where the expansion appears in a declarator like the example given in 18.104.22.168 [dcl.fct] paragraph 13:
template<typename... T> void f(T (* ...t)(int, int));
This is also described as a pack expansion, although it does not fit the syntactic summary.
Proposed resolution (November, 2010):
This issue is resolved by the resolution of issue 778.