[Bug c++/83918] [8 Regression][c++17] ICE on constexpr eval of datatype involving function and variadic template

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83918

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2018-01-18
                 CC|                            |dmalcolm at gcc dot gnu.org,
                   |                            |jakub at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with r256448.

Small formatting cleanup:
constexpr unsigned
foo (unsigned x, unsigned y)
{
  return x > b ? x : y;
}

template <typename, typename> struct A;
template <auto ...> struct B;
template <auto S, auto ... T, auto U, auto ... V>
struct A <B <S, T...>, B <U, V...>>
{
  enum : unsigned
  {
    u = foo (sizeof (S), sizeof (U)),
    v = A <B <T...>, B <V...>>::w,
    w = foo (u, v)
  };
};

template <>
struct A <B <>, B <>>
{
  enum : unsigned { w = 0 };
};

constexpr static const auto v { A <B <1,2,3,4,5,6,7,8,9>,
                                   B <9,8,7,6,5,4,3,2,1>>::w };
static_assert (v == sizeof (int));