[Bug c++/88875] [9 regression] initializer_list and explicit ctor

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88875

--- Comment #2 from Nathan Sidwell <nathan at gcc dot gnu.org> ---
That change looks suspicious in its own right -- it ends up mutating the
initializer during the adding of overload candidates.