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 status at the April, 2013 meeting.]
There does not appear to be any technical difficulty that would require the restriction in 7.5.5 [expr.prim.lambda] paragraph 5 against default arguments in lambda-expressions.
Proposed resolution (August, 2011):
Delete the following sentence from 7.5.5 [expr.prim.lambda] paragraph 5:
Default arguments (126.96.36.199 [dcl.fct.default]) shall not be specified in the parameter-declaration-clause of a lambda-declarator.
Additional note (February, 2012):
EWG requested that the adoption of this proposed resolution be postponed to allow them to discuss it. The issue has thus been returned to "review" status pending EWG action.