[Bug c++/87513] [8/9 Regression] ICE in write_expression, at cp/mangle.c:3050

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87513

--- Comment #7 from Martin Liška <marxin at gcc dot gnu.org> ---
Reduced test-case:

$ cat ice.ii
template < int a > struct b { static constexpr int c = a; };
template < typename > struct d;
template < typename > struct e;
template < typename f, typename g > struct e< f g::* > : b< d< f >::c > {};
template < typename h, typename... i > struct d< h(i...) > : b< true > {};
template < typename > class j;
struct k {
  typedef int l;
};
template < bool, bool, typename... > struct m;
template < typename ab, typename n, typename... o >
struct m< false, true, ab, n, o... > : k {};
template < typename ac, typename... i >
struct ad : m< b< false >::c, e< ac >::c, i... > {};
template < typename ac, typename... i >
struct j< ac(i...) > : ad< ac, i... > {};
class p {
public:
  p(char *);
};
class q {
public:
  template < long > void r();
};
class s {
public:
  template < long t >
  auto ae(p) -> typename j< decltype (&q::r< t >)(q, p) >::l;
};
using z = s;
void f() {
  z ag;
  ag.ae< 0 >("");
}