[Bug c++/89214] [7/8/9 Regression] ICE in digest_init_r, at cp/typeck2.c:1211 with -std=c++17

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89214

--- Comment #6 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Somewhat cleaned up test:

struct A
{
  A (int);
};

struct BB
{
  A v;
};

struct B : BB
{};

B
foo ()
{
  return {{B {{42}}}};
}