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 current wording of 7.5.5 [expr.prim.lambda] paragraphs 15 and 16 does not, but presumably should, indicate that this, if implicitly captured, is always captured by copy and not by reference.
Proposed resolution (February, 2016):
Change 7.5.5 [expr.prim.lambda] paragraph 15 as follows, dividing the existing text into a bulleted list:
An entity is captured by copy if
it is implicitly captured and the capture-default is = or
ifit is explicitly captured with a capture that is not of the form & identifier or & identifier initializer.
For each entity captured by copy...
Notes from the February, 2016 meeting:
Paper P0018 is intended to change this area, so this issue is being returned to "review" status to accommodate those changes.