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.
The grammar for member-declarator (11.4 [class.mem]) does not, but should, allow for a brace-or-equal-initializer on a bit-field declarator.
Rationale (October, 2015):
Such a change would introduce a new syntactic ambiguity. CWG also felt uncomfortable with a construct that is visually
expression = expression
not being an assignment expression.