[Bug c++/65301] gcc can't detect some uninit reads in ctor init lists

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65301

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I pointed out other similar cases in
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=18016#c9 when fixing the simple
case of args(args)