[Bug c++/116015] ICE in replace_placeholders_r for simple default member initializer

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116015

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
(Not a regression; previously we rejected the code.)