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.
[Moved to DR at the October, 2012 meeting.]
The current wording of the Standard does not describe what happens when a decltype-specifier is used as a nested-name-specifier and the type denoted by the decltype-specifier is neither a class type nor an enumeration type. Such nested-name-specifiers should be prohibited, presumably somewhere around paragraphs 8-10 of _N4567_.5.1.1 [expr.prim.general]. (The corresponding prohibition for named types is handled as part of lookup in 6.5.5 [basic.lookup.qual] paragraph 1.)
Proposed resolution (February, 2012):
Add the following immediately after the grammar in _N4567_.5.1.1 [expr.prim.general] paragraph 8 and move the text following that point into a new paragraph:
A nested-name-specifier that denotes a class...