[Bug c++/100899] [10 Regression] internal compiler error: in retrieve_specialization, at cp/pt.c:1240

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100899

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2021-06-07
      Known to fail|                            |10.1.0, 10.2.0, 10.3.0
   Target Milestone|---                         |10.4
            Summary|internal compiler error: in |[10 Regression] internal
                   |retrieve_specialization, at |compiler error: in
                   |cp/pt.c:1240                |retrieve_specialization, at
                   |                            |cp/pt.c:1240
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=99009
                 CC|                            |ppalka at gcc dot gnu.org
      Known to work|                            |11.1.0, 9.4.0

--- Comment #2 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Confirmed.  GCC 9 accepts the testcase.  We began ICEing on it after r10-4719. 
We began accepting it again after r11-7483.

Reduced:

template <typename> class Grammar {
public:
  template <typename...> class Sequence {};
};
enum ValueType {};
class JsonGrammar : Grammar<ValueType> {
  void integer() { Sequence(); }
};