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 May, 2015 meeting.]
The grammar in 5.10 [lex.name] includes the production,
The rule for “other implementation-defined characters” is a holdover from before the introduction of universal-character-names, intended to allow the use of non-ASCII national characters in identifiers. However, since all characters outside the basic source character set are now conceptually mapped to universal-character-names in translation phase 1, there is no longer a need for such a provision and it should be removed.
Proposed resolution (April, 2015):
Change the grammar in 5.10 [lex.name] as follows: