[Bug c++/89419] New: [8/9 Regression] ICE in is_normal_capture_proxy starting with r253601

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89419

            Bug ID: 89419
           Summary: [8/9 Regression] ICE in is_normal_capture_proxy
                    starting with r253601
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jakub at gcc dot gnu.org
  Target Milestone: ---

The following testcase started to ICE with -std=c++17 in r253601:
struct A;
struct B {
  struct C { C (); C (C &); } b;
};
struct D { A operator* (); };
struct A {
  template <typename T> void foo (T x) { x (this); }
};
struct E {
  auto bar () { return e; }
  D e;
};
struct F { B f; int g; };

int
main ()
{
  E e;
  auto f = *e.bar ();
  auto i = [&] { F g; g.g = 1; auto h = [&](auto) { g.g = 0; }; f.foo (h);
return g; };
}