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.
11.9.3 [class.base.init] paragraph 3 singles out base classes when indicating the allowance of typedefs, etc. for the naming of types in a mem-initializer-list. It appears that the omission of the class of the constructor is unintentional.
Rationale (November, 2016):
There was no actual issue; the question was based on a misunderstanding of the current specification.