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.
11.8.5 [class.protected] paragraph 1 begins:
When a friend or a member function of a derived class references a protected nonstatic member of a base class, an access check applies in addition to those described earlier in 11.8 [class.access] .
This was intended to refer to nonstatic member functions and nonstatic data members. However, a protected nested type declared in a base class is, by some definition of the word, a "nonstatic" member, and therefore subject to this additional access check.
Proposed resolution (10/99): change "protected nonstatic member" in the above to "protected nonstatic member function or protected nonstatic data member" to make the intent clear.