[Bug c++/99201] [8/9/10/11 Regression] ICE in tsubst_copy, at cp/pt.c:16581

[kretz at kde dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99201

--- Comment #5 from Matthias Kretz (Vir) <kretz at kde dot org> ---
I reduced it some more:

template <typename RefF>
  auto
  make_tester(const RefF& reffun)
  {
    return [=](auto in) {
      auto&& expected = [&](const auto&... vs) {
        if constexpr (sizeof(in) > 0)
          return [&](auto i) { return reffun(vs[i]...); }(0);
        else
          return [&](auto i) { return reffun(vs[i]...); }(0);
      };
    };
  }

int main()
{
  make_tester([](auto x) { return x; })(0);
  return 0;
}