[Bug c++/121287] ICE: Segfault in tsubst_lambda_expr with decltype of immediately-invoked templated lambda + variadic lambda expansion (GCC 13+)

[mpolacek at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121287

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|needs-reduction             |

--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
// PR c++/121287
// { dg-do compile { target c++20 } }

template <typename _Tp, _Tp...> struct integer_sequence {};
template <long... _Idx>
using index_sequence = integer_sequence<unsigned long, _Idx...>;
template <typename> struct array {};

template <typename = void>
auto
f ()
{
  using Res = decltype([]<unsigned long Idx>(index_sequence<Idx>) {
}(index_sequence<3>{}));
  return []<long...>(index_sequence<>) { array<Res>{}; }({});
}

void
g ()
{
  f ();
}