https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97358
--- Comment #10 from Jason Merrill <jason at gcc dot gnu.org> ---
This doesn't look valid to me. In
[x...] { x; }...
we capture the entire pack, but then try to use only a single element. This
should be rejected because the use of x in the lambda body is not expanded, as
with the clang error for option 3 in comment #7. Probably what they mean is
[x] { x; }...
or, as you say,
[=] { x; }...
