[Bug c++/68724] [4.9/5/6 Regression] ice in unify, at cp/pt.c:19902

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68724

Nathan Sidwell <nathan at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
                 CC|                            |nathan at gcc dot gnu.org
           Assignee|unassigned at gcc dot gnu.org      |nathan at gcc dot gnu.org

--- Comment #2 from Nathan Sidwell <nathan at gcc dot gnu.org> ---
One can turn it into the syntactically correct:
template <typename _Tp, _Tp>
  struct integral_constant {
  };

  struct X : integral_constant < bool, true >{
  };

template <typename _Tp>
struct integral_constant < bool, __is_enum(_Tp)> {
};

but still get the ICE when unify meets an unexpected TRAIT_EXPR.