https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81862
--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Reduced. But the PR86917 is much simpler, so I'd start with fixing that one.
template <unsigned long...> struct b;
template <typename, typename> struct g;
template <unsigned long... c, unsigned long... d> struct g<b<c...>, b<d...>> {
using e = b<c..., d...>;
};
template <int f>
struct i : g<typename i<f / 2>::e, typename i<f - f / 2>::e> {};
template <> struct i<1> { typedef b<0> e; };
template <typename h, h...> struct j {};
template <typename h, h f, typename = typename i<f>::e> struct o;
template <typename h, h f, unsigned long... k> struct o<h, f, b<k...>> {
typedef j<h, k...> e;
};
template <typename h, h f> using l = typename o<h, f>::e;
template <long... k> using m = j<unsigned long, k...>;
template <long f> using n = l<unsigned long, f>;
struct q {
constexpr q(int) { }
};
template <int p> struct G { typedef q r[p]; };
template <int p> struct H {
typename G<p>::r s;
q operator[](long);
};
template <typename... t> class I {
public:
constexpr I(t... v) : I(v..., n<5>{}) {}
template <unsigned long... w>
constexpr I(t... v, m<w...> x) : u({y(v..., x)[w]...}) {}
template <unsigned long... w> auto y(t..., m<w...>) {
H<5> a{w...};
return a;
}
q u[5];
};
int main() { I<int, bool> c(2, false); }
